1,721 research outputs found

    Production of α\alpha-particle condensate states in heavy-ion collisions

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    The fragmentation of quasi-projectiles from the nuclear reaction 40Ca^{40}Ca + 12C^{12}C at 25 MeV/nucleon was used to produce excited states candidates to α\alpha-particle condensation. The experiment was performed at LNS-Catania using the CHIMERA multidetector. Accepting the emission simultaneity and equality among the α\alpha-particle kinetic energies as experimental criteria for deciding in favor of the condensate nature of an excited state, we analyze the 02+0_2^+ and 22+2_2^+ states of 12^{12}C and the 06+0_6^+ state of 16^{16}O. A sub-class of events corresponding to the direct 3-α\alpha decay of the Hoyle state is isolated.Comment: contribution to the 2nd Workshop on "State of the Art in Nuclear Cluster Physics" (SOTANCP2), Universite Libre de Bruxelles (Belgium), May 25-28, 2010, to be published in the International Journal of Modern Physics

    Alpha-particle condensation in excited 12C

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    The fragmentation of quasi-projectiles from the nuclear reaction 40Ca^{40}Ca+12C^{12}C at 25 MeV/nucleon was used to produce excited states candidates to α\alpha-particle condensation. The methodology relies on high granularity 4π\pi detection coupled to correlation function techniques. Under the assumption that the equality among the kinetic energies of the emitted α\alpha-particles and the emission simultaneity constitutes a reliable fingerprint of α\alpha condensation, we identify several tens of events corresponding to the deexcitation of the Hoyle state of 12^{12}C which fulfill the condition.Comment: 5 pages, 3 figure

    Probing clustering in excited alpha-conjugate nuclei

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    15 pages, 6 figures, accepted in Physics Letters B; International audience; The fragmentation of quasi-projectiles from the nuclear reaction 40^{40}Ca+12^{12}C at 25 MeV per nucleon bombarding energy was used to produce α\alpha-emission sources. From a careful selection of these sources provided by a complete detection and from comparisons with models of sequential and simultaneous decays, evidence in favor of α\alpha-particle clustering from excited 16O^{16}O, 20Ne^{20}Ne and 24Mg^{24}Mg is reported

    Evidence for α\alpha-particle condensation in nuclei from the Hoyle state deexcitation

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    The fragmentation of quasi-projectiles from the nuclear reaction 40^{40}Ca+12^{12}C at 25 MeV/nucleon was used to produce excited states candidates to α\alpha-particle condensation. Complete kinematic characterization of individual decay events, made possible by a high-granularity 4π\pi charged particle multi-detector, reveals that 7.5±\pm4.0% of the particle decays of the Hoyle state correspond to direct decays in three equal-energy α\alpha-particles.Comment: Phys. Lett. B, in pres

    Propuesta de un nuevo modelo microquirúrgico para el estudio de la endometriosis inducida en rata Wistar. Resultados preliminares

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    The current knowledge status on the patogenesis of endometriosis as well as devastating consequences of disease evolution in women's reproductive health, have promoted researchers advances in a great manner during last years. The immunologic and neangiogenesis systems implication have opened new ways of knowledge over classic theories from the beginning of the xx century. The experimental resesearch, using animal induction models. Below we explain the first steps a new induction model ("PGR1-HotDog"), based on Wistar rats using a new disease autogeneration system, created for te study of the early stages of the endometriosis

    Overview of recent TJ-II stellarator results

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    The main results obtained in the TJ-II stellarator in the last two years are reported. The most important topics investigated have been modelling and validation of impurity transport, validation of gyrokinetic simulations, turbulence characterisation, effect of magnetic configuration on transport, fuelling with pellet injection, fast particles and liquid metal plasma facing components. As regards impurity transport research, a number of working lines exploring several recently discovered effects have been developed: the effect of tangential drifts on stellarator neoclassical transport, the impurity flux driven by electric fields tangent to magnetic surfaces and attempts of experimental validation with Doppler reflectometry of the variation of the radial electric field on the flux surface. Concerning gyrokinetic simulations, two validation activities have been performed, the comparison with measurements of zonal flow relaxation in pellet-induced fast transients and the comparison with experimental poloidal variation of fluctuations amplitude. The impact of radial electric fields on turbulence spreading in the edge and scrape-off layer has been also experimentally characterized using a 2D Langmuir probe array. Another remarkable piece of work has been the investigation of the radial propagation of small temperature perturbations using transfer entropy. Research on the physics and modelling of plasma core fuelling with pellet and tracer-encapsulated solid-pellet injection has produced also relevant results. Neutral beam injection driven Alfvénic activity and its possible control by electron cyclotron current drive has been examined as well in TJ-II. Finally, recent results on alternative plasma facing components based on liquid metals are also presentedThis work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 under Grant Agreement No. 633053. It has been partially funded by the Ministerio de Ciencia, Inovación y Universidades of Spain under projects ENE2013-48109-P, ENE2015-70142-P and FIS2017-88892-P. It has also received funds from the Spanish Government via mobility grant PRX17/00425. The authors thankfully acknowledge the computer resources at MareNostrum and the technical support provided by the Barcelona S.C. It has been supported as well by The Science and Technology Center in Ukraine (STCU), Project P-507F

    Choice of the initial antiretroviral treatment for HIV-positive individuals in the era of integrase inhibitors

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    BACKGROUND: We aimed to describe the most frequently prescribed initial antiretroviral therapy (ART) regimens in recent years in HIV-positive persons in the Cohort of the Spanish HIV/AIDS Research Network (CoRIS) and to investigate factors associated with the choice of each regimen. METHODS: We analyzed initial ART regimens prescribed in adults participating in CoRIS from 2014 to 2017. Only regimens prescribed in >5% of patients were considered. We used multivariable multinomial regression to estimate Relative Risk Ratios (RRRs) for the association between sociodemographic and clinical characteristics and the choice of the initial regimen. RESULTS: Among 2874 participants, abacavir(ABC)/lamivudine(3TC)/dolutegavir(DTG) was the most frequently prescribed regimen (32.1%), followed by tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC)/elvitegravir(EVG)/cobicistat(COBI) (14.9%), TDF/FTC/rilpivirine (RPV) (14.0%), tenofovir alafenamide (TAF)/FTC/EVG/COBI (13.7%), TDF/FTC+DTG (10.0%), TDF/FTC+darunavir/ritonavir or darunavir/cobicistat (bDRV) (9.8%) and TDF/FTC+raltegravir (RAL) (5.6%). Compared with ABC/3TC/DTG, starting TDF/FTC/RPV was less likely in patients with CD4100.000 copies/mL. TDF/FTC+DTG was more frequent in those with CD4100.000 copies/mL. TDF/FTC+RAL and TDF/FTC+bDRV were also more frequent among patients with CD4<200 cells//muL and with transmission categories other than men who have sex with men. Compared with ABC/3TC/DTG, the prescription of other initial ART regimens decreased from 2014-2015 to 2016-2017 with the exception of TDF/FTC+DTG. Differences in the choice of the initial ART regimen were observed by hospitals' location. CONCLUSIONS: The choice of initial ART regimens is consistent with Spanish guidelines' recommendations, but is also clearly influenced by physician's perception based on patient's clinical and sociodemographic variables and by the prescribing hospital location

    Lack of evidence for KRAS oncogenic mutations in triple-negative breast cancer

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    <p>Abstract</p> <p>Background</p> <p>Mutational analysis of the <it>KRAS </it>gene has recently been established as a complementary <it>in vitro </it>diagnostic tool for the identification of patients with colorectal cancer who will not benefit from anti-epidermal growth factor receptor (EGFR) therapies. Assessment of the mutation status of <it>KRAS </it>might also be of potential relevance in other EGFR-overexpressing tumors, such as those occurring in breast cancer. Although <it>KRAS </it>is mutated in only a minor fraction of breast tumors (5%), about 60% of the basal-like subtype express EGFR and, therefore could be targeted by EGFR inhibitors. We aimed to study the mutation frequency of <it>KRAS </it>in that subtype of breast tumors to provide a molecular basis for the evaluation of anti-EGFR therapies.</p> <p>Methods</p> <p>Total, genomic DNA was obtained from a group of 35 formalin-fixed paraffin-embedded, triple-negative breast tumor samples. Among these, 77.1% (27/35) were defined as basal-like by immunostaining specific for the established surrogate markers cytokeratin (CK) 5/6 and/or EGFR. <it>KRAS </it>mutational status was determined in the purified DNA samples by Real Time (RT)-PCR using primers specific for the detection of wild-type <it>KRAS </it>or the following seven oncogenic somatic mutations: Gly12Ala, Gly12Asp, Gly12Arg, Gly12Cys, Gly12Ser, Gly12Val and Gly13Asp.</p> <p>Results</p> <p>We found no evidence of <it>KRAS </it>oncogenic mutations in all analyzed tumors.</p> <p>Conclusions</p> <p>This study indicates that <it>KRAS </it>mutations are very infrequent in triple-negative breast tumors and that EGFR inhibitors may be of potential benefit in the treatment of basal-like breast tumors, which overexpress EGFR in about 60% of all cases.</p

    A fast, very-high-energy γ -ray flare from BL Lacertae during a period of multi-wavelength activity in June 2015

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    The mechanisms producing fast variability of the γ-ray emission in active galactic nuclei (AGNs) are under debate. The MAGIC telescopes detected a fast, very-high-energy (VHE, E &gt; 100 GeV) γ-ray flare from BL Lacertae on 2015 June 15. The flare had a maximum flux of (1.5 ± 0.3) × 10-10 photons cm-2 s-1 and halving time of 26 ± 8 min. The MAGIC observations were triggered by a high state in the optical and high-energy (HE, E &gt; 100 MeV) γ-ray bands. In this paper we present the MAGIC VHE γ-ray data together with multi-wavelength data from radio, optical, X-rays, and HE γ rays from 2015 May 1 to July 31. Well-sampled multi-wavelength data allow us to study the variability in detail and compare it to the other epochs when fast, VHE γ-ray flares have been detected from this source. Interestingly, we find that the behaviour in radio, optical, X-rays, and HE γ-rays is very similar to two other observed VHE γ-ray flares. In particular, also during this flare there was an indication of rotation of the optical polarization angle and of activity at the 43 GHz core. These repeating patterns indicate a connection between the three events. We also test modelling of the spectral energy distribution based on constraints from the light curves and VLBA observations, with two different geometrical setups of two-zone inverse Compton models. In addition we model the γ-ray data with the star-jet interaction model. We find that all of the tested emission models are compatible with the fast VHE γ-ray flare, but all have some tension with the multi-wavelength observations
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