321 research outputs found

    Vanishing chiral couplings in the large-N_C resonance theory

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    The construction of a resonance theory involving hadrons requires implementing the information from higher scales into the couplings of the effective Lagrangian. We consider the large-Nc chiral resonance theory incorporating scalars and pseudoscalars, and we find that, by imposing LO short-distance constraints on form factors of QCD currents constructed within this theory, the chiral low-energy constants satisfy resonance saturation at NLO in the 1/Nc expansion.Comment: 5 pages, 2 figures. Version published in Physical Review D. Some equations to facilitate the discussion have been adde

    Lepton Flavour Violation in charged leptons within SUSY-seesaw

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    In this paper we review our main results for Lepton Flavour Violating (LFV) semileptonic tau decays and muon-electron conversion in nuclei within the context of two Constrained SUSY-Seesaw Models, the CMSSM and the NUHM. The relevant spectrum is that of the Minimal Supersymmetric Standard Model extended by three right handed neutrinos, νRi\nu_{R_i} and their corresponding SUSY partners, ν~Ri{\tilde \nu}_{R_i}, (i=1,2,3i=1,2,3). We use the seesaw mechanism for neutrino mass generation and choose a parameterisation of this mechanism that allows us to incorporate the neutrino data in our analysis of LFV processes. In addition to the full one-loop results for the rates of these processes, we will also review the set of simple formulas, valid at large tanβ\tan \beta, which are very useful to compare with present experimental bounds. The sensitivity to SUSY and Higgs sectors in these processes will also be discussed. This is a very short summary of the works in Refs. \cite{Arganda:2008jj} and \cite{Arganda:2007jw} to which we refer the reader for more details.Comment: 6 pages, 6 figures. To be published in the proceedings of the Tau08 Conference, Novosibirsk, Russia, 22-25 September 200

    Hadron structure in tau -> KKpi nu_tau decays

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    We analyse the hadronization structure of both vector and axial-vector currents leading to tau -> KKpi nu_tau decays. At leading order in the 1/Nc expansion, and considering only the contribution of the lightest resonances, we work out, within the framework of the resonance chiral Lagrangian, the structure of the local vertices involved in those processes. The couplings in the resonance theory are constrained by imposing the asymptotic behaviour of vector and axial-vector spectral functions ruled by QCD. In this way we predict the hadron spectra and conclude that, contrarily to previous assertions, the vector contribution dominates by far over the axial-vector one in all KKpi charge channels.Comment: 32 pages, 7 figure

    Las fosfatidilinositol 3-cinasas de clase I en la inmunidad: Efecto de inhibidores en respuestas inmunes y autoinmunes

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    Las fosfatidilinositol 3-cinasas (PI3K) de clase I dan lugar a fosfolípidos trifosforilados (PtdIns(3,4,5)P3) que son clave en las señales de crecimiento, diferenciación y la supervivencia de las células y son esenciales para el funcionamiento de la inmunidad innata y adaptativa. Los nuevos inhibidores de PI3K generados para el tratamiento de tumores pueden ser útiles en inmunoterapia, especialmente en enfermedades autoinmunes, y ha de investigarse su impacto en la inmunidad anti tumoral. Se revisa el papel de las PI3K de clase I en las respuestas inmunes adaptativas, y los datos conocidos relativos al efecto de inhibidores en respuestas inmunes adaptativas.Las fosfatidilinositol 3-cinasas (PI3K) de clase I dan lugar a fosfolípidos trifosforilados (PtdIns(3,4,5)P3) que son clave en las señales de crecimiento, diferenciación y la supervivencia de las células y son esenciales para el funcionamiento de la inmunidad innata y adaptativa. Los nuevos inhibidores de PI3K generados para el tratamiento de tumores pueden ser útiles en inmunoterapia, especialmente en enfermedades autoinmunes, y ha de investigarse su impacto en la inmunidad anti tumoral. Se revisa el papel de las PI3K de clase I en las respuestas inmunes adaptativas, y los datos conocidos relativos al efecto de inhibidores en respuestas inmunes adaptativas

    Dificultades algebraicas en la resolución de problemas por transferencia

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    La enseñanza de resolución de problemas en ciencias y matemáticas se realiza en general mediante estrategias de transferencia (transfer): se resuelve y explica un conjunto de problemas y después se pide a los estudiantes que resuelvan otros problemas análogos a los ejemplos trabajados. Los profesores de Secundaria con frecuencia asumen que las relaciones analógicas entre los problemas resueltos y los problemas propuestos son sencillas de comprender y establecer, y atribuyen el fracaso a la falta de dominio de los procedimientos matemáticos de resolución. En este trabajo se realiza un experimento para probar si esta atribución causal es adecuada o no. Los resultados demuestran que la causa principal de las dificultades debe tener su origen en la construcción de un modelo de la situación y/o de un modelo del problema, adecuados

    Evidence of topological superconductivity in planar Josephson junctions

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    Majorana zero modes are quasiparticle states localized at the boundaries of topological superconductors that are expected to be ideal building blocks for fault-tolerant quantum computing. Several observations of zero-bias conductance peaks measured in tunneling spectroscopy above a critical magnetic field have been reported as experimental indications of Majorana zero modes in superconductor/semiconductor nanowires. On the other hand, two dimensional systems offer the alternative approach to confine Ma jorana channels within planar Josephson junctions, in which the phase difference {\phi} between the superconducting leads represents an additional tuning knob predicted to drive the system into the topological phase at lower magnetic fields. Here, we report the observation of phase-dependent zero-bias conductance peaks measured by tunneling spectroscopy at the end of Josephson junctions realized on a InAs/Al heterostructure. Biasing the junction to {\phi} ~ {\pi} significantly reduces the critical field at which the zero-bias peak appears, with respect to {\phi} = 0. The phase and magnetic field dependence of the zero-energy states is consistent with a model of Majorana zero modes in finite-size Josephson junctions. Besides providing experimental evidence of phase-tuned topological superconductivity, our devices are compatible with superconducting quantum electrodynamics architectures and scalable to complex geometries needed for topological quantum computing.Comment: main text and extended dat

    A user-centered chatbot to identify and interconnect individual, social and environmental risk factors related to overweight and obesity

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    [EN] The objective of this study was to assess the feasibility of using a user-centered chatbotfor collecting linked data to study overweight and obesity causes ina target population. In total 980 people participated in the feasibility study organized in three studies: (1) within a group of university students (88 participants), (2) in a small town (422 participants), and (3) within a university community (470 participants). We gathered self-reported data through the Wakamola chatbot regarding participants diet, physical activity, social network, living area, obesity-associated diseases, and sociodemographic data. For each study, we calculated the mean Body Mass Index (BMI) and number of people in each BMI level. Also, we defined and calculated scores (1-100 scale) regarding global health, BMI, alimentation, physical activity and social network. Moreover, we graphically represented obesity risk for living areas and the social network with nodes colored by BMI. Students group results: Mean BMI 21.37 (SD 2.57) (normal weight), 8 people underweight, 5 overweight, 0 obesity, global health status 78.21, alimentation 63.64, physical activity 65.08 and social 26.54, 3 areas with mean BMI level of obesity, 17 with overweight level. Small town ' s study results: Mean BMI 25.66 (SD 4.29) (overweight), 2 people underweight, 63 overweight, 26 obesity, global health status 69.42, alimentation 64.60, physical activity 60.61 and social 1.14, 1 area with mean BMI in normal weight; University ' s study results: Mean BMI 23.63 (SD 3.7) (normal weight), 22 people underweight, 86 overweight, 28 obesity, global health status 81.03, alimentation 81.84, physical activity 70.01 and social 1.47, 3 areas in obesity level, 19 in overweight level. Wakamola is a health care chatbot useful to collect relevant data from populations in the risk of overweight and obesity. Besides, the chatbot provides individual self-assessment of BMI and general status regarding the style of living. Moreover, Wakamola connects users in a social network to help the study of O & O ' s causes from an individual, social and socio-economic perspective.Funding for this study was provided by the authors' various departments, and partially by the Crowd Health Project (Collective Wisdom Driving Public Health Policies [727560]).Asensio-Cuesta, S.; Blanes-Selva, V.; Conejero, JA.; Portolés, M.; Garcia-Gomez, JM. (2022). A user-centered chatbot to identify and interconnect individual, social and environmental risk factors related to overweight and obesity. Informatics for Health and Social Care. 47(1):38-52. https://doi.org/10.1080/17538157.2021.1923501385247

    Form Factors in the radiative pion decay

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    We perform an analysis of the form factors that rule the structure-dependent amplitude in the radiative pion decay. The resonance contributions to pion -> e nu_e gamma decays are computed through the proper construction of the vector and axial-vector form factors by setting the QCD driven asymptotic properties of the three-point Green functions VVP and VAP, and by demanding the smoothing of the form factors at high transfer of momentum. A comparison between theoretical and experimental determinations of the form factors is also carried out. We also consider and evaluate the role played by a non-standard tensor form factor. We conclude that, at present and due to the hadronic incertitudes, the search for New Physics in this process is not feasible.Comment: 14 pages, no figures. Typos corrected. Accepted for publication in The European Physical Journal

    Tailoring hierarchical meso- macroporous 3D scaffolds: from nano to macro

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    Bone tissue regeneration requires the use of 3D scaffolds which mimic the architecture of the natural extracellular matrix, creating an adequate microenvironment for bone cell growth. Such 3D scaffolds need surface properties suitable for biological recognition in the early stage of cell adhesion, necessary to ensure complete cell colonization, retained cell functionality, and subsequently bone regeneration. Herein, hierarchical 3D scaffolds based on new hydroxyapatite/mesoporous glass nanocomposite bioceramic (MGHA) exhibiting different scales of porosity have been synthesized. These 3D scaffolds possess: (i) highly ordered mesopores with diameters of 10 nm; (ii) macropores with diameters in the 30-80 mu m range with interconnections of 1-10 mu m; and (iii) large macropores of ca. 500 mu m. To improve their surface properties, 3D scaffolds were modified through direct functionalization with amine propyl groups, which notably improve preosteoblast adhesion, proliferation (2.3 fold), differentiation (4.8 fold) and further cell colonization of these scaffolds. The observed enhancement can be related to these amine groups which favour early adhesion, e. g., based on nonspecific protein adsorption as was demonstrated by ellipsometry. These results suggest that the combination of hierarchical structure design and amine surface modification of hydroxyapatite/mesoporous nanocomposite scaffolds yields a double increase in cell proliferation, as well as a quadruple increase in cell differentiation, demonstrating the potential of these nanocomposite materials for bone tissue regeneration purposes

    La pérdida específica de células T de la subunidad catalítica p110? de PI-3-linasa da como resultado una producción mejorada de citocinas y una respuesta antitumoral

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    Class IA phosphatidylinositol 3-kinase (PI3K) catalytic subunits p110? and p110? are targets in cancer therapy expressed at high levels in T lymphocytes. The role of p110? PI3K in normal or pathological immune responses is well established, yet the importance of p110? subunits in T cell-dependent immune responses is not clear. To address this problem, mice with p110? conditionally deleted in CD4+ and CD8+ T lymphocytes (p110??/??T) were used. p110??/??T mice show normal development of T cell subsets, but slightly reduced numbers of CD4+ T cells in the spleen. “In vitro,” TCR/CD3 plus CD28 activation of naive CD4+ and CD8+ p110??/??T T cells showed enhanced effector function, particularly IFN-? secretion, T-bet induction, and Akt, Erk, or P38 activation. Tfh derived from p110??/??T cells also have enhanced responses when compared to normal mice, and IL-2 expanded p110??/??T CD8+ T cells had enhanced levels of LAMP-1 and Granzyme B. By contrast, the expansion of p110??/??T iTreg cells was diminished. Also, p110??/??T mice had enhanced anti-keyhole limpet hemocyanin (KLH) IFN-?, or IL-4 responses and IgG1 and IgG2b anti-KLH antibodies, using CFA or Alum as adjuvant, respectively. When compared to WT mice, p110??/??T mice inoculated with B16.F10 melanoma showed delayed tumor progression. The percentage of CD8+ T lymphocytes was higher and the percentage of Treg cells lower in the spleen of tumor-bearing p110??/??T mice. Also, IFN-? production in tumor antigen-activated spleen cells was enhanced. Thus, PI3K p110? plays a significant role in antigen activation and differentiation of CD4+ and CD8+ T lymphocytes modulating antitumor immunity
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