482 research outputs found

    A Mixed Hybrid Algorithm for Integral Wind Farm Optimum Design

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    . Nowadays, the weight of the generation of renewable energies has grown spectacularly with regard to other conventional energies. This is due to diverse factors: a bigger environmental concern (Kyoto protocol, white-book in EU, etc.), the raising prices of the traditional fuels, etc. On the other hand, wind power has experienced a bigger grown, among the renewable energies. That is why the development of an effective tool for the design and lay-out of wind farms has a special relevance. This paper present a mix of evolutionary algorithms to look for the optimum integral design of the wind park taking into account all the part involved: number of wind generators, the type and the height of the wind generators, its location, the number and location of substations, the best layout of lowvoltage and high-voltage lines among wind generators, substations and the existing transmission lines, etc. Due to problem complexity, and as a first approach, the global optimization problem has been splitted in two main (uncoupled) parts, first the wind generators lay out and then the network configurationMinisterio de Ciencia y Tecnología ENE2004-03342/CONMinisterio de Ciencia y Tecnología DPI2002-04416-C04-02Junta de Andalucía ACC-1021-TIC-200

    Efficacy of direct current generated by multiple-electrode arrays on F3II mammary carcinoma: experiment and mathematical modeling

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    BACKGROUND: The modified Gompertz equation has been proposed to fit experimental data for direct current treated tumors when multiple-straight needle electrodes are individually inserted into the base perpendicular to the tumor long axis. The aim of this work is to evaluate the efficacy of direct current generated by multiple-electrode arrays on F3II mammary carcinoma that grow in the male and female BALB/c/Cenp mice, when multiple-straight needle electrodes and multiple-pairs of electrodes are inserted in the tumor. METHODS: A longitudinal and retrospective preclinical study was carried out. Male and female BALB/c/Cenp mice, the modified Gompertz equation, intensities (2, 6 and 10 mA) and exposure times (10 and 20 min) of direct current, and three geometries of multiple-electrodes (one formed by collinear electrodes and two by pair-electrodes) were used. Tumor volume and mice weight were measured. In addition, the mean tumor doubling time, tumor regression percentage, tumor growth delay, direct current overall effectiveness and mice survival were calculated. RESULTS: The greatest growth retardation, mean doubling time, regression percentage and growth delay of the primary F3II mammary carcinoma in male and female mice were observed when the geometry of multiple-pairs of electrodes was arranged in the tumor at 45, 135, 225 and 325o and the longest exposure time. In addition, highest direct current overall effectiveness (above 66%) was observed for this EChT scheme. CONCLUSIONS: It is concluded that electrochemical therapy may be potentially addressed to highly aggressive and metastic primary F3II murine mammary carcinoma and the modified Gompertz equation may be used to fit data of this direct current treated carcinoma. Additionally, electrochemical therapy effectiveness depends on the exposure time, geometry of multiple-electrodes and ratio between the direct current intensity applied and the polarization current induced in the tumor

    Steppes, savannahs, forests and phytodiversity reservoirs during the Pleistocene in the Iberian Peninsula

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    A palaeobotanical analysis of the Pleistocene floras and vegetation in the Iberian Peninsula shows the existence of patched landscapes with Pinus woodlands, deciduous and mixed forests, parklands (savannah-like), shrublands, steppes and grasslands. Extinctions of Arctotertiary woody taxa are recorded during the Early and Middle Pleistocene, but glacial refugia facilitated the survival of a number of temperate, Mediterranean and Ibero-North African woody angiosperms. The responses of Iberian vegetation to climatic changes during the Pleistocene have been spatially and temporarily complex, including rapid changes of vegetation in parallel to orbital and suborbital variability, and situations of multi-centennial resilience or accommodation to climatic changes. Regional characteristics emerged as soon as for the Middle Pleistocene, if not earlier: Ericaceae in the Atlantic coast indicating wetter climate, thermo-mediterranean elements in the south as currently, and broad-leaf trees in the northeastern. Overall, steppe landscapes and open Pinus woodlands prevailed over many continental regions during the cold spells of the Late Pleistocene. The maintenance of a high phytodiversity during the glacials was linked to several refuge zones in the coastal shelves of the Mediterranean and intramountainous valleys. Northern Iberia, especially on coastal areas, was also patched with populations of tree species, and this is not only documented by palaeobotanical data (pollen, charcoal) but also postulated by phylogeographical models

    Chronic lymphocytic leukemia patients with IGH translocations are characterized by a distinct genetic landscape with prognostic implications

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    Chromosome 14q32 rearrangements/translocations involving the immunoglobulin heavy chain (IGH) are rarely detected in chronic lymphocytic leukemia (CLL). The prognostic significance of the IGH translocation is controversial and its mutational profile remains unknown. Here, we present for the first time a comprehensive next-generation sequencing (NGS) analysis of 46 CLL patients with IGH rearrangement (IGHR-CLLs) and we demonstrate that IGHR-CLLs have a distinct mutational profile with recurrent mutations in NOTCH1, IGLL5, POT1, BCL2, FBXW7, ZMYM3, MGA, BRAF and HIST1H1E genes. Interestingly, BCL2 and FBXW7 mutations were significantly associated with this subgroup and almost half of BCL2, IGLL5 and HISTH1E mutations reported were previously identified in non-Hodgkin lymphomas. Notably, IGH/BCL2 rearrangements were associated with a lower mutation frequency and carried BCL2 and IGLL5 mutations, while the other IGHR-CLLs had mutations in genes related to poor prognosis (NOTCH1, SF3B1 and TP53) and shorter time to first treatment (TFT). Moreover, IGHR-CLLs patients showed a shorter TFT than CLL patients carrying 13q-, normal fluorescence in situ hybridization (FISH) and +12 CLL, being this prognosis particularly poor when NOTCH1, SF3B1, TP53, BIRC3 and BRAF were also mutated. The presence of these mutations not only was an independent risk factor within IGHR-CLLs, but also refined the prognosis of low-risk cytogenetic patients (13q-/normal FISH). Hence, our study demonstrates that IGHR-CLLs have a distinct mutational profile from the majority of CLLs and highlights the relevance of incorporating NGS and the status of IGH by FISH analysis to refine the risk-stratification CLL model

    Small-scale solar magnetic fields

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    As we resolve ever smaller structures in the solar atmosphere, it has become clear that magnetism is an important component of those small structures. Small-scale magnetism holds the key to many poorly understood facets of solar magnetism on all scales, such as the existence of a local dynamo, chromospheric heating, and flux emergence, to name a few. Here, we review our knowledge of small-scale photospheric fields, with particular emphasis on quiet-sun field, and discuss the implications of several results obtained recently using new instruments, as well as future prospects in this field of research.Comment: 43 pages, 18 figure

    Length of carotid stenosis predicts peri-procedural stroke or death and restenosis in patients randomized to endovascular treatment or endarterectomy.

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    BACKGROUND: The anatomy of carotid stenosis may influence the outcome of endovascular treatment or carotid endarterectomy. Whether anatomy favors one treatment over the other in terms of safety or efficacy has not been investigated in randomized trials. METHODS: In 414 patients with mostly symptomatic carotid stenosis randomized to endovascular treatment (angioplasty or stenting; n = 213) or carotid endarterectomy (n = 211) in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS), the degree and length of stenosis and plaque surface irregularity were assessed on baseline intraarterial angiography. Outcome measures were stroke or death occurring between randomization and 30 days after treatment, and ipsilateral stroke and restenosis ≥50% during follow-up. RESULTS: Carotid stenosis longer than 0.65 times the common carotid artery diameter was associated with increased risk of peri-procedural stroke or death after both endovascular treatment [odds ratio 2.79 (1.17-6.65), P = 0.02] and carotid endarterectomy [2.43 (1.03-5.73), P = 0.04], and with increased long-term risk of restenosis in endovascular treatment [hazard ratio 1.68 (1.12-2.53), P = 0.01]. The excess in restenosis after endovascular treatment compared with carotid endarterectomy was significantly greater in patients with long stenosis than with short stenosis at baseline (interaction P = 0.003). Results remained significant after multivariate adjustment. No associations were found for degree of stenosis and plaque surface. CONCLUSIONS: Increasing stenosis length is an independent risk factor for peri-procedural stroke or death in endovascular treatment and carotid endarterectomy, without favoring one treatment over the other. However, the excess restenosis rate after endovascular treatment compared with carotid endarterectomy increases with longer stenosis at baseline. Stenosis length merits further investigation in carotid revascularisation trials

    Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum

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    We report a first measurement for ultra-high energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the `ankle' at lg(E/eV)=18.519.0\lg(E/{\rm eV})=18.5-19.0 differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass A>4A > 4. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report Numbe

    Anisotropy studies around the galactic centre at EeV energies with the Auger Observatory

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    Data from the Pierre Auger Observatory are analyzed to search for anisotropies near the direction of the Galactic Centre at EeV energies. The exposure of the surface array in this part of the sky is already significantly larger than that of the fore-runner experiments. Our results do not support previous findings of localized excesses in the AGASA and SUGAR data. We set an upper bound on a point-like flux of cosmic rays arriving from the Galactic Centre which excludes several scenarios predicting sources of EeV neutrons from Sagittarius AA. Also the events detected simultaneously by the surface and fluorescence detectors (the `hybrid' data set), which have better pointing accuracy but are less numerous than those of the surface array alone, do not show any significant localized excess from this direction.Comment: Matches published versio

    Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}=2.76 TeV

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    The elliptic, v2v_2, triangular, v3v_3, and quadrangular, v4v_4, azimuthal anisotropic flow coefficients are measured for unidentified charged particles, pions and (anti-)protons in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV with the ALICE detector at the Large Hadron Collider. Results obtained with the event plane and four-particle cumulant methods are reported for the pseudo-rapidity range η<0.8|\eta|<0.8 at different collision centralities and as a function of transverse momentum, pTp_{\rm T}, out to pT=20p_{\rm T}=20 GeV/cc. The observed non-zero elliptic and triangular flow depends only weakly on transverse momentum for pT>8p_{\rm T}>8 GeV/cc. The small pTp_{\rm T} dependence of the difference between elliptic flow results obtained from the event plane and four-particle cumulant methods suggests a common origin of flow fluctuations up to pT=8p_{\rm T}=8 GeV/cc. The magnitude of the (anti-)proton elliptic and triangular flow is larger than that of pions out to at least pT=8p_{\rm T}=8 GeV/cc indicating that the particle type dependence persists out to high pTp_{\rm T}.Comment: 16 pages, 5 captioned figures, authors from page 11, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186

    Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm{NN}}} = 2.76 TeV

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    The inclusive transverse momentum (pTp_{\rm T}) distributions of primary charged particles are measured in the pseudo-rapidity range η<0.8|\eta|<0.8 as a function of event centrality in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm{NN}}}=2.76 TeV with ALICE at the LHC. The data are presented in the pTp_{\rm T} range 0.15<pT<500.15<p_{\rm T}<50 GeV/cc for nine centrality intervals from 70-80% to 0-5%. The Pb-Pb spectra are presented in terms of the nuclear modification factor RAAR_{\rm{AA}} using a pp reference spectrum measured at the same collision energy. We observe that the suppression of high-pTp_{\rm T} particles strongly depends on event centrality. In central collisions (0-5%) the yield is most suppressed with RAA0.13R_{\rm{AA}}\approx0.13 at pT=6p_{\rm T}=6-7 GeV/cc. Above pT=7p_{\rm T}=7 GeV/cc, there is a significant rise in the nuclear modification factor, which reaches RAA0.4R_{\rm{AA}} \approx0.4 for pT>30p_{\rm T}>30 GeV/cc. In peripheral collisions (70-80%), the suppression is weaker with RAA0.7R_{\rm{AA}} \approx 0.7 almost independently of pTp_{\rm T}. The measured nuclear modification factors are compared to other measurements and model calculations.Comment: 17 pages, 4 captioned figures, 2 tables, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/284
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