1,935 research outputs found

    Charged Current Neutrino Cross Section and Tau Energy Loss at Ultra-High Energies

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    We evaluate both the tau lepton energy loss produced by photonuclear interactions and the neutrino charged current cross section at ultra-high energies, relevant to neutrino bounds with Earth-skimming tau neutrinos, using different theoretical and phenomenological models for nucleon and nucleus structure functions. The theoretical uncertainty is estimated by taking different extrapolations of the structure function F2 to very low values of x, in the low and moderate Q2 range for the tau lepton interaction and at high Q2 for the neutrino-nucleus inelastic cross section. It is at these extremely low values of x where nuclear shadowing and parton saturation effects are unknown and could be stronger than usually considered. For tau and neutrino energies E=10^9 GeV we find uncertainties of a factor 4 for the tau energy loss and of a factor 2 for the charged current neutrino-nucleus cross section.Comment: 20 pages and 11 figure

    Penalized regression on principal manifolds with application to combustion modelling

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    For multivariate regression problems featuring strong and non–linear dependency patterns between the involved predictors, it is attractive to reduce the dimension of the estimation problem by approximating the predictor space through a principal surface (or manifold). In this work, a new approach for non- parametric regression onto the fitted manifold is provided. The proposed penal- ized regression technique is applied onto data from a simulated combustion sys- tem, and is shown, in this application, to compare well with competing regression routines

    A mulher e o cancro do pulmão**Textos referentes à mesa-redonda com o mesmo título organizada pela Comissão de Trabalho de «Pneumologia Oncológica». Coimbra, 13 de Abril de 2002

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    ABSTRACTThe epidemiology of lung cancer has changed in the last years in several countries all over the world. In the 19th century, the lung cancer was rare but it incidence increase drastically during the 20th century, and the tendency is to continue in the 20th century. Actually the lung cancer’s incidence and mortality are higher in the developed countries, especially in Europe and Unites States of America, with a increasing in the women incidence. These geographic differences and gender differences are related with smoking habits.Women begin to smoke earlier and have more difficulty to stop, because of problems related with obesity; they have more sensibility to the carcinogens and the risk of lung cancer is 1,5 times higher than the men with the same habits.Adenocarcinoma is the more frequent histological type in young people, in the total of the women and in non-smokers.Many factors since tobacco, home and professional pollution, nutritional, associated diseases even genetic and hormonal factors have been investigated to define its influence in development in women lung cancer.It specificity in women with lung cancer is the comum problem for the medical people to treat this disease (pathology).The literature about this problem is not clear, and is necessary to advance with many studies in this arca with the objective to clarify this important question.REV PORT PNEUMOL 2003; IX (3): 225-24

    Next-to-next-to-leading order fits to CCFR'97 xF3xF_3 data and infrared renormalons

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    We briefly summarize the outcomes of our recent improved fits to the experimental data of CCFR collaboration for xF3xF_3 structure function of νN\nu N deep-inelastic scattering at the next-to-next-to-leading order. Special attention is paid to the extraction of αs(MZ)\alpha_s(M_Z) and the parameter of the infrared renormalon model for 1/Q21/Q^2-correction at different orders of perturbation theory. The results can be of interest for planning similar studies using possible future data of Neutrino Factories.Comment: 3 pages, presented at WG3 of 4th NuFact'02 Workshop, London 1-6 July, 200

    Forebulge migration in the foreland basin system of the central-southern Apennine fold-thrust belt (Italy): New high-resolution Sr-isotope dating constraints

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    The Apennines are a retreating collisional belt where the foreland basin system, across large domains, is floored by a subaerial forebulge unconformity developed due to forebulge uplift and erosion. This unconformity is overlain by a diachronous sequence of three lithostratigraphic units made of (a) shallow-water carbonates, (b) hemipelagic marls and shales and (c) siliciclastic turbidites. Typically, the latter two have been interpreted regionally as the onset of syn-orogenic deposition in the foredeep depozone, whereas little attention has been given to the underlying unit. Accordingly, the rate of migration of the central-southern Apennine fold-thrust belt-foreland basin system has been constrained, so far, exclusively considering the age of the hemipelagites and turbidites, which largely post-date the onset of foredeep depozone. In this work, we provide new high-resolution ages obtained by strontium isotope stratigraphy applied to calcitic bivalve shells sampled at the base of the first syn-orogenic deposits overlying the Eocene-Cretaceous pre-orogenic substratum. Integration of our results with published data indicates progressive rejuvenation of the strata sealing the forebulge unconformity towards the outer portions of the fold-thrust belt. In particular, the age of the forebulge unconformity linearly scales with the pre-orogenic position of the analysed sites, pointing to an overall constant migration velocity of the forebulge wave in the last 25 Myr

    The direct renin inhibitor aliskiren improves vascular remodelling in transgenic rats harbouring human renin and angiotensinogen genes

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    In the present study, we tested the hypothesis that chronic treatment with the direct rennin inhibitor aliskiren improves the remodelling of resistance arteries in dTGR (double-transgenic rats). dTGR (5 weeks) were treated with aliskiren (3 mg/kg of body mass per day) or ramipril (1 mg/kg of body mass per day) for 14 days and compared with age-matched vehicle-treated dTGR. BP (blood pressure) was similarly reduced in both aliskiren-treated and ramipril-treated rats compared with control dTGR (167± 1 and 169± 2 mmHg compared with 197± 4 mmHg respectively; P<0.05). The M/L (media-to-lumen) ratio assessed on pressurized preparations was equally reduced in aliskiren-treated and ramipril-treated rats compared with controls (6.3± 0.5 and 6.4±0.2% compared with 9.8± 0.4% respectively; P<0.05). Endothelium-dependent and -independent relaxations were similar among the groups. L-NAME (NG-nitro-L-arginine methyl ester) significantly reduced acetylcholine-induced dilation in drug-treated dTGR. This effect was significantly more prominent in aliskiren-treated rats. eNOS (endothelial NO synthase) expression showed a 2-fold increase only in aliskiren-treated dTGR as compared with controls (P<0.01) and ramipril-treated dTGR (P<0.05). Plasma nitrite, as an index of NO production, was significantly increased in dTGR treated with either aliskiren or ramipril compared with controls. Only aliskiren induced a 2-fold increase in plasma nitrite, which was significantly greater than that induced by ramipril (P<0.05). gp91phox expression and ROS (reactive oxygen species) production in aorta were significantly and similarly reduced by both drugs. In conclusion, equieffective hypotensive doses of aliskiren or ramipril reduced the M/L ratio of mesenteric arteries and improved oxidative stress in dTGR. However, only aliskiren increased further NO production in the vasculature. Hence, in dTGR, direct renin inhibition induces favourable effects similar to that induced by ACE (angiotensin-converting enzyme) inhibition in improving vascular remodelling through different mechanisms. © The Authors Journal compilation. 2013 Biochemical Society

    Zn-Fe flower-like nanoparticles growth by gas condensation

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    Bimetallic nanoparticles have gained attention in the last decade due to their unusual characteristics compared to monometallic counterparts. However, production of such particles with controlled morphologies and composition need to be explored and the mechanisms understood. In this work, we demonstrate a fast and simple process to obtain flower-like Zn-Fe (Zinc-Iron) nanoparticles (NPs) using a hybrid system based on the combination of conventional magnetron sputtering and a cluster beam source. The morphology and structure were characterized by Scanning transmission electron microscopy (STEM), while the chemical composition was evaluated by simultaneous acquisition of Energy-dispersive X-ray spectroscopy (EDS) and Electron energy loss spectroscopy (EELS). Besides, molecular dynamic simulations were used to model the nanoparticle collisions during the simultaneous production, revealing the formation mechanisms of the flower-like nanoparticles.The authors thank the financial support by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/04650/2020 and by project NANOXYPACK cofinanced via FEDER (PT2020) POCI-01-0145-FEDER-030789.info:eu-repo/semantics/publishedVersio

    Blackwell-Optimal Strategies in Priority Mean-Payoff Games

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    We examine perfect information stochastic mean-payoff games - a class of games containing as special sub-classes the usual mean-payoff games and parity games. We show that deterministic memoryless strategies that are optimal for discounted games with state-dependent discount factors close to 1 are optimal for priority mean-payoff games establishing a strong link between these two classes

    Role of Duplex Scan in Endoleak Detection After Endoluminal Abdominal Aortic Aneurysm Repair

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    AbstractObjective: to validate the role of duplex scan in endoleak detection in postoperative surveillance of endoluminal abdominal aneurysm repair (EAAR). Patients and methods between April 1997 and March 1999, 103 patients were eligible for duplex and computed tomography (CT) scan after EAAR. Mean follow-up was 8 months (range 1–24 months). The study protocol comprised concurrent examination with colour-duplex and CT scan at 1, 6, and 12 months after EAAR, for a total of 198 concurrent examinations. All duplex scan examinations were performed by two vascular surgeons with the same machine (ATL HDI 3000). Interobserver agreement in endoleak detection (κ=1) and in type of endoleak (κ=0.7) was evaluated in 50 random duplex examinations. Endoleak detection was examined comparatively in duplex and CT scan, the latter being the gold standard. Sensitivity and specificity tests together with negative- and positive-predictive values (NPV and PPV) were calculated. Results duplex scan was not feasible in one patient. On CT scan the endoleak rate was 4% at one month, 3% at 6 months, and 4% at one year. Overall, CT scan detected 12 endoleaks. With respect to endoleak detection, duplex scan revealed a great ability in ruling out false-negative results (sensitivity 91.7%, NPV 99.4%), but overestimated the presence of endoleak (specificity 98.4%, PPV 78.6%). Regarding type of endoleak, the ability of duplex scan to identify the source of endoleak was low (sensitivity 66.7%). Conclusions duplex scan, if validated, appears to be a reliable means for excluding the presence of endoleak after EAAR
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