283 research outputs found

    Testing Supersymmetry with Lepton Flavor Violating tau and mu decays

    Full text link
    In this work the following lepton flavor violating τ\tau and μ\mu decays are studied: τ−→μ−μ−μ+\tau^- \to \mu^- \mu^- \mu^+, τ−→e−e−e+\tau^- \to e^- e^- e^+, μ−→e−e−e+\mu^- \to e^- e^- e^+, τ−→μ−γ\tau^- \to \mu^- \gamma, τ−→e−γ\tau^- \to e^- \gamma and μ−→e−γ\mu^- \to e^- \gamma. We work in a supersymmetric scenario consisting of the minimal supersymmetric standard model particle content, extended by the addition of three heavy right handed Majorana neutrinos and their supersymmetric partners, and where the generation of neutrino masses is done via the seesaw mechanism. Within this context, a significant lepton flavor mixing is generated in the slepton sector due to the Yukawa neutrino couplings, which is transmited from the high to the low energies via the renormalization group equations. This slepton mixing then generates via loops of supersymmetric particles significant contributions to the rates of lj→3lil_j \to 3 l_i and the correlated lj→liγl_j \to l_i \gamma decays. We analize here in full detail these rates in terms of the relevant input parameters, which are the usual minimal supergravity parameters and the seesaw parameters. For the lj→3lil_j \to 3 l_i decays, a full one-loop analytical computation of all the contributing supersymmetric loops is presented. This completes and corrects previous computations in the literature. In the numerical analysis compatibility with the most recent experimental upper bounds on all these τ\tau and μ\mu decays, with the neutrino data, and with the present lower bounds on the supersymmetric particle masses are required. Two typical scenarios with degenerate and hierarchical heavy neutrinos are considered. We will show here that the minimal supergravity and seesaw parameters do get important restrictions from these τ\tau and μ\mu decays in the hierarchical neutrino case.Comment: Version to appear in Physical Review

    Black-box modeling to estimate tissue temperature during radiofrequency catheter cardiac ablation: feasibility study on an agar phantom model

    Full text link
    This is an author-created, un-copyedited versíon of an article published in Physiological Measurement. IOP Publishing Ltd is not responsíble for any errors or omissíons in this versíon of the manuscript or any versíon derived from it. The Versíon of Record is available online at http://doi.org/10.1088/0967-3334/31/4/009[EN] The aim of this work was to study linear deterministic models to predict tissue temperature during radiofrequency cardiac ablation (RFCA) by measuring magnitudes such as electrode temperature, power and impedance between active and dispersive electrodes. The concept involves autoregressive models with exogenous input (ARX), which is a particular case of the autoregressive moving average model with exogenous input (ARMAX). The values of the mode parameters were determined from a least-squares fit of experimental data. The data were obtained from radiofrequency ablations conducted on agar models with different contact pressure conditions between electrode and agar (0 and 20 g) and different flow rates around the electrode (1, 1.5 and 2 L min¿1). Half of all the ablations were chosen randomly to be used for identification (i.e. determination of model parameters) and the other half were used for model validation. The results suggest that (1) a linear model can be developed to predict tissue temperature at a depth of 4.5 mm during RF cardiac ablation by using the variables applied power, impedance and electrode temperature; (2) the best model provides a reasonably accurate estimate of tissue temperature with a 60% probability of achieving average errors better than 5 °C; (3) substantial errors (larger than 15 °C) were found only in 6.6% of cases and were associated with abnormal experiments (e.g. those involving the displacement of the ablation electrode) and (4) the impact of measuring impedance on the overall estimate is negligible (around 1 °C).This work was supported by the 'Plan Nacional de Investigacion Cientifica, Desarrollo e Innovacion Tecnologica del Ministerio de Educacion y Ciencia' of Spain (TEC200801369/ TEC) and by an R&D contract (CSIC-20060633) between Edwards Lifescience Ltd and the Spanish National Research Council (CSIC). The English revision and correction of this paper was funded by the Universidad Politecnica de Valencia, Spain. We thank L Melecio for his invaluable technical support in conducting the experiments.Blasco-Giménez, R.; Lequerica, JL.; Herrero, M.; Hornero, F.; Berjano, E. (2010). Black-box modeling to estimate tissue temperature during radiofrequency catheter cardiac ablation: feasibility study on an agar phantom model. Physiological Measurement. 31(4):581-594. https://doi.org/10.1088/0967-3334/31/4/009S581594314Hong Cao, Tungjitkusolmun, S., Young Bin Choy, Jang-Zern Tsai, Vorperian, V. R., & Webster, J. G. (2002). Using electrical impedance to predict catheter-endocardial contact during RF cardiac ablation. IEEE Transactions on Biomedical Engineering, 49(3), 247-253. doi:10.1109/10.983459Hong Cao, Vorperian, V. R., Jang-Zem Tsai, Tungjitkusolmun, S., Eung Je Woo, & Webster, J. G. (2000). Temperature measurement within myocardium during in vitro RF catheter ablation. IEEE Transactions on Biomedical Engineering, 47(11), 1518-1524. doi:10.1109/10.880104Hamner, C. E., Potter, D. D., Cho, K. R., Lutterman, A., Francischelli, D., Sundt, T. M., & Schaff, H. V. (2005). Irrigated Radiofrequency Ablation With Transmurality Feedback Reliably Produces Cox Maze Lesions In Vivo. The Annals of Thoracic Surgery, 80(6), 2263-2270. doi:10.1016/j.athoracsur.2005.06.017HARTUNG, W. M., BURTON, M. E., DEAM, A. G., WALTER, P. F., McTEAGUE, K., & LANGBERG, J. J. (1995). Estimation of Temperature During Radiofrequency Catheter Ablation Using Impedance Measurements. Pacing and Clinical Electrophysiology, 18(11), 2017-2021. doi:10.1111/j.1540-8159.1995.tb03862.xDing Sheng He, Bosnos, M., Mays, M. Z., & Marcus, F. (2003). Assessment of myocardial lesion size during in vitro radio frequency catheter ablation. IEEE Transactions on Biomedical Engineering, 50(6), 768-776. doi:10.1109/tbme.2003.812161KO, W.-C., HUANG, S. K. S., LIN, J.-L., SHAU, W.-Y., LAI, L.-P., & CHEN, P. H. (2001). New Method for Predicting Efficiency of Heating by Measuring Bioimpedance During Radiofrequency Catheter Ablation in Humans. Journal of Cardiovascular Electrophysiology, 12(7), 819-823. doi:10.1046/j.1540-8167.2001.00819.xLabonte, S. (1994). Numerical model for radio-frequency ablation of the endocardium and its experimental validation. IEEE Transactions on Biomedical Engineering, 41(2), 108-115. doi:10.1109/10.284921Lai, Y.-C., Choy, Y. B., Haemmerich, D., Vorperian, V. R., & Webster, J. G. (2004). Lesion Size Estimator of Cardiac Radiofrequency Ablation at Different Common Locations With Different Tip Temperatures. IEEE Transactions on Biomedical Engineering, 51(10), 1859-1864. doi:10.1109/tbme.2004.831529Lequerica, J. L., Berjano, E. J., Herrero, M., Melecio, L., & Hornero, F. (2008). A cooled water-irrigated intraesophageal balloon to prevent thermal injury during cardiac ablation: experimental study based on an agar phantom. Physics in Medicine and Biology, 53(4), N25-N34. doi:10.1088/0031-9155/53/4/n01Mattingly, M., Bailey, E. A., Dutton, A. W., Roemer, R. B., & Devasia, S. (1998). Reduced-order modeling for hyperthermia: an extended balanced-realization-based approach. IEEE Transactions on Biomedical Engineering, 45(9), 1154-1162. doi:10.1109/10.709559PILCHER, T. A., SANFORD, A. L., SAUL, J. P., & HAEMMERICH, D. (2006). Convective Cooling Effect on Cooled-Tip Catheter Compared to Large-Tip Catheter Radiofrequency Ablation. Pacing and Clinical Electrophysiology, 29(12), 1368-1374. doi:10.1111/j.1540-8159.2006.00549.xRodríguez, I., Lequerica, J. L., Berjano, E. J., Herrero, M., & Hornero, F. (2007). Esophageal temperature monitoring during radiofrequency catheter ablation: experimental study based on an agar phantom model. Physiological Measurement, 28(5), 453-463. doi:10.1088/0967-3334/28/5/001SCHUMACHER, B., EICK, O., WITTKAMPF, F., PEZOLD, C., TEBBENJOHANNS, J., JUNG, W., & LUDERITZ, B. (1999). Temperature Response Following Nontraumatic Low Power Radiofrequency Application. Pacing and Clinical Electrophysiology, 22(2), 339-343. doi:10.1111/j.1540-8159.1999.tb00448.xTeixeira, C. A., Ruano, A. E., Ruano, M. G., Pereira, W. C. A., & Negreira, C. (2006). Non-invasive temperature prediction of in vitro therapeutic ultrasound signals using neural networks. Medical & Biological Engineering & Computing, 44(1-2), 111-116. doi:10.1007/s11517-005-0004-2Teixeira, C. A., Ruano, M. G., Ruano, A. E., & Pereira, W. C. A. (2008). A Soft-Computing Methodology for Noninvasive Time-Spatial Temperature Estimation. IEEE Transactions on Biomedical Engineering, 55(2), 572-580. doi:10.1109/tbme.2007.90102

    Improved prediction of the optical properties in pi-conjugated polymers: the case of benzochalcogenodiazole-based copolymers with different heteroatom substitution

    Get PDF
    Donor−acceptor (D−A) approach to conjugated polymer design has become a widely used method for preparing conjugated polymers with narrow band gaps.1 One outstanding D−A polymer is poly(cyclopentadithiophene)benzothiadiazole, PCPDTBT (P1 in Figure 1), for which power conversion efficiencies in solar cells of 4.5-5.5% are reported.2 In this work, we use resonance Raman (RR) and density functional theory (DFT) calculations to investigate the tuning of the electronic and structural properties of cyclopentadithiophene-benzochalcogenodiazole D−A polymers, wherein a single atom in the benzochalcogenodiazole unit is varied from sulfur to selenium to tellurium (Fig. 1).3 Sophisticated DFT calculations have been carried out using long-range corrected functionals, considering both tuned and default range-separation parameters, aiming at predicting their optical and charge transport properties. In addition, the nature of the electronic excitation is described by analyzing the enhancement pattern in the RR spectra using Raman excitation wavelengths coincident with the various transitions in the copolymers.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    Semen parameters can be predicted from environmental factors and lifestyle using artificial intelligence methods

    Get PDF
    Fertility rates have dramatically decreased in the last two decades, especially in men. It has been described that environmental factors as well as life habits may affect semen quality. In this paper we use artificial intelligence techniques in order to predict semen characteristics resulting from environmental factors, life habits, and health status, with these techniques constituting a possible decision support system that can help in the study of male fertility potential. A total of 123 young, healthy volunteers provided a semen sample that was analyzed according to the World Health Organization 2010 criteria. They also were asked to complete a validated questionnaire about life habits and health status. Sperm concentration and percentage of motile sperm were related to sociodemographic data, environmental factors, health status, and life habits in order to determine the predictive accuracy of a multilayer perceptron network, a type of artificial neural network. In conclusion, we have developed an artificial neural network that can predict the results of the semen analysis based on the data collected by the questionnaire. The semen parameter that is best predicted using this methodology is the sperm concentration. Although the accuracy for motility is slightly lower than that for concentration, it is possible to predict it with a significant degree of accuracy. This methodology can be a useful tool in early diagnosis of patients with seminal disorders or in the selection of candidates to become semen donors.This study was partially funded by Vicerrectorado de Investigación, University of Alicante, Alicante, Spain (Vigrob-137)

    A new Method for determining Compound Specific Carbon Isotope of Chlorinated Solvents in Porewater

    Get PDF
    A new method for the extraction of chlorinated solvents (CSs) from porewater with dimethylacetamide (DMA) used as a solvent and the determination of δ13C by gas chromatography-isotope ratio mass spectrometry (GC-IRMS) with solid-phase microextraction (SPME) are presented. This method was used for the determination of δ13C of chloroethenes and chloromethanes. The extraction of the CSs from porewater with DMA led to a minimal loss of mass of solvent and chlorinated compounds. The accuracy of the method was verified with the analysis of the pure injected compounds using elemental analyser - isotope ratio mass spectrometry (EA-IRMS). It has been effectively applied in a study area in saturated soil samples of a pollutant source zone of perchloroethylene (PCE) and trichloroethylene (TCE). The limit of quantification of the new method was 0.034 µg/g for PCE and TCE for 10-20 g of soil sample. This new method allows for compound-specific isotope analysis (CSIA) of CSs in porewater, which can be beneficial in sites where the identification of contamination sources and the behaviour of the contaminants are not clear

    Flood Hazard Management in Public Mountain Recreation Areas vs. Ungauged Fluvial Basins. Case Study of the Caldera de Taburiente National Park, Canary Islands (Spain)

    Get PDF
    Las Angustias River is an ungauged stream in the Caldera de Taburiente National Park (Spain), where frequent intense flash-flood events occur. The aim of this research is to analyze the flood hazard at the Playa de Taburiente. Based on the limited information available (short time-series of daily precipitation), a statistical frequency analysis of 24 h rainfall was completed and the precipitation results were transformed into surface runoff. To determine if the model underestimates the flows that are generated in the basin, the dendro-geomorphological information available was used to calibrate results. The results of the HMS model were significantly lower. At this point, both the rainfall data and the rainfall-runoff model were re-analyzed to maximize the rainfall intensity values and the runoff generated (increasing the CN value for the basin). For the 1997 flood event, a 1250 m3·s−1 flood minimizes the RMSE for the disturbed tree sample; this flow value also clearly exceeds any peak flow derived from the rainfall-runoff analysis. It is only when rainfall intensity and surface runoff are maximized that the peak flows obtained approximate those associated with dendro-geomorphological data. The results highlight the difficulties of flood hazard management in ungauged torrential basins in mountain recreational areas (such as National Parks). Thus, in the absence of flow records, when considering the maximum rainfall intensity scenario may be a useful and effective tool for flood risk management

    Natural attenuation of pools and plumes of carbon tetrachloride and chloroform in the transition zone to bottom aquitards and the microorganisms involved in their degradation

    Full text link
    In the transition zone between aquifers and aquitards, DNAPL pools of carbon tetrachloride and chloroform accumulate because of heterogeneity in this zone. Natural attenuation occurs at pools and plumes, indicating that remediation might be possible. The aims of the study were: i) to assess the role of heterogeneity in the natural attenuation of these compounds, ii) determine degradation processes within this zone, and iii) identify dechlorinating microorganisms. For this, groundwater concentrations, redox-sensitive parameters, CSIA isotopic and DGGE molecular techniques were used. The main findings at depth of the transition zone were: (1) the important key control played by heterogeneity on natural attenuation of contaminants. (2) Heterogeneity caused the highly anoxic environment and dominant sulfate-reducing conditions, which accounts for more efficient natural attenuation. (3) Heterogeneity also explains that the transition zone constitutes an ecotone. (4) The bacteria size exclusion is governed by the pore throat threshold and determines the penetration of dechlorinating microorganisms into the finest sediments, which is relevant, since it implies the need to verify whether microorganisms proposed for bioremediation can penetrate these materials. (5) Reductive dechlorination caused the natural attenuation of contaminants in groundwater and porewater of fine sediments. In the case of carbon tetrachloride, it was an abiotic process biogenically mediated by A. suillum, a bacterium capable of penetrating the finest sediments. In the case of chloroform, it was a biotic process performed by a Clostridiales bacterium, which is unable to penetrate the finest materials. (6) Both microorganisms have potential to be biostimulated to dechlorinate contaminants in the source and the plume in the transition zone. These outcomes are particularly relevant given the longevity of DNAPL sources and have considerable environmental implications as many supply wells in industrial areas exploit aquifers contaminated by chlorinated solvents emerging from DNAPL pools accumulated on the low-conductivity layers in transition zones

    Lepton flavor violating Higgs boson decays from massive seesaw neutrinos

    Full text link
    Lepton flavor violating Higgs boson decays are studied within the context of seesaw models with Majorana massive neutrinos. Two models are considered: The SM-seesaw, with the Standard Model Particle content plus three right handed neutrinos, and the MSSM-seesaw, with the Minimal Supersymmetric Standard Model particle content plus three right handed neutrinos and their supersymmetric partners. The widths for these decays are derived from a full one-loop diagrammatic computation in both models, and they are analyzed numerically in terms of the seesaw parameters, namely, the Dirac and Majorana mass matrices. Several possible scenarios for these mass matrices that are compatible with neutrino data are considered. In the SM-seesaw case, very small branching ratios are found for all studied scenarios. These ratios are explained as a consequence of the decoupling behaviour of the heavy right handed neutrinos. In contrast, in the MSSM-seesaw case, sizeable branching ratios are found for some of the leptonic flavor violating decays of the MSSM neutral Higgs bosons and for some choices of the seesaw matrices and MSSM parameters. The relevance of the two competing sources of lepton flavor changing interactions in the MSSM-seesaw case is also discussed. The non-decoupling behaviour of the supersymmetric particles contributing in the loop-diagrams is finally shown.Comment: 44pgs. Version to appear in Phys.Rev.
    • …
    corecore