582 research outputs found

    Exciton Gas Compression and Metallic Condensation in a Single Semiconductor Quantum Wire

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    We study the metal-insulator transition in individual self-assembled quantum wires and report optical evidences of metallic liquid condensation at low temperatures. Firstly, we observe that the temperature and power dependence of the single nanowire photoluminescence follow the evolution expected for an electron-hole liquid in one dimension. Secondly, we find novel spectral features that suggest that in this situation the expanding liquid condensate compresses the exciton gas in real space. Finally, we estimate the critical density and critical temperature of the phase transition diagram at nc1×105n_c\sim1\times10^5 cm1^{-1} and Tc35T_c\sim35 K, respectively.Comment: 4 pages, 5 figure

    Umbrales económicos para la araña roja Tetranychus urticae (acari: Tetranychidae) en mandarino

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    Tetranychus urticae es una plaga clave en cítricos, especialmente en mandarina clementina. Se evaluó el daño de este ácaro sobre la producción de 24 árboles de clementino durante tres años consecutivos. Los árboles fueron visitados semanalmente, y se estimó tanto la población de araña roja como la de ácaros fitoseidos, así como la brotación. Al final de cada temporada, se recolectaron las clementinas, se pesaron, y se evaluó el daño ocasionado por T. urticae en fruto. Se encontró una relación negativa entre la densidad de la araña roja y el rendimiento (kg/árbol). Sin embargo, las correlaciones entre el daño en fruto y los diferentes estimadores de araña roja fueron más fuertes. Las regresiones multivariantes destacaron el papel clave que juegan tanto los ácaros fitoseidos como la brotación, que se correlacionaron negativamente con el daño en fruto. El período más corto de muestreo que predijo satisfactoriamente el daño en fruto en la recolección, se extendió desde el 1 agosto hasta mediados de octubre. A efectos de Gestión Integrada de Plagas, se estimó un umbral económico de daños de 31,14 hembras adultas de araña roja en hoja sintomática por m2. Teniendo en cuenta la dinámica poblacional de T. urticae, el umbral de intervención varió de 10 a 15 hembras adultas de araña roja en hoja sintomática por m2 . Cuando se supera este umbral, los agricultores tendrían una ventana de una semana para aplicar cualquiera de las medidas (biológicas o químicas) que disponen contra T. urticae.Este trabajo fue parcialmente finan- ciado por el Ministerio de Ciencia e Innovación (proyectos AGL2011- 30538-C03-01-07464 AGL2004-C03- 01, AGL2005-07155-C03, y AGL2008- 05287-C04-03/AGR). S.P.R. y E.A.F. fueron beneficiarias de una beca pre- doctoral del MICINN y de la UJI, respectivamente

    NEXT-100 Technical Design Report (TDR). Executive Summary

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    In this Technical Design Report (TDR) we describe the NEXT-100 detector that will search for neutrinoless double beta decay (bbonu) in Xe-136 at the Laboratorio Subterraneo de Canfranc (LSC), in Spain. The document formalizes the design presented in our Conceptual Design Report (CDR): an electroluminescence time projection chamber, with separate readout planes for calorimetry and tracking, located, respectively, behind cathode and anode. The detector is designed to hold a maximum of about 150 kg of xenon at 15 bar, or 100 kg at 10 bar. This option builds in the capability to increase the total isotope mass by 50% while keeping the operating pressure at a manageable level. The readout plane performing the energy measurement is composed of Hamamatsu R11410-10 photomultipliers, specially designed for operation in low-background, xenon-based detectors. Each individual PMT will be isolated from the gas by an individual, pressure resistant enclosure and will be coupled to the sensitive volume through a sapphire window. The tracking plane consists in an array of Hamamatsu S10362-11-050P MPPCs used as tracking pixels. They will be arranged in square boards holding 64 sensors (8 times8) with a 1-cm pitch. The inner walls of the TPC, the sapphire windows and the boards holding the MPPCs will be coated with tetraphenyl butadiene (TPB), a wavelength shifter, to improve the light collection.Comment: 32 pages, 22 figures, 5 table

    NLRP3 inflammasome activation and symptom burden in KRAS-mutated CMML patients is reverted by IL-1 blocking therapy

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    Chronic myelomonocytic leukemia (CMML) is frequently associated with mutations in the rat sarcoma gene (RAS), leading to worse prognosis. RAS mutations result in active RAS-GTP proteins, favoring myeloid cell proliferation and survival and inducing the NLRP3 inflammasome together with the apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), which promote caspase-1 activation and interleukin (IL)-1(3 release. Here, we report, in a cohort of CMML patients with mutations in KRAS, a constitutive activation of the NLRP3 inflammasome in monocytes, evidenced by ASC oligomerization and IL-1(3 release, as well as a specific inflammatory cytokine signature. Treatment of a CMML patient with a KRASG12D mutation using the IL-1 receptor blocker anakinra inhibits NLRP3 inflammasome activation, reduces monocyte count, and improves the patient's clinical status, enabling a stem cell transplant. This reveals a basal inflammasome activation in RAS-mutated CMML patients and suggests potential therapeutic applications of NLRP3 and IL-1 blockers

    Study of Leading Hadrons in Gluon and Quark Fragmentation

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    The study of quark jets in e+e- reactions at LEP has demonstrated that the hadronisation process is reproduced well by the Lund string model. However, our understanding of gluon fragmentation is less complete. In this study enriched quark and gluon jet samples of different purities are selected in three-jet events from hadronic decays of the Z collected by the DELPHI experiment in the LEP runs during 1994 and 1995. The leading systems of the two kinds of jets are defined by requiring a rapidity gap and their sum of charges is studied. An excess of leading systems with total charge zero is found for gluon jets in all cases, when compared to Monte Carlo Simulations with JETSET (with and without Bose-Einstein correlations included) and ARIADNE. The corresponding leading systems of quark jets do not exhibit such an excess. The influence of the gap size and of the gluon purity on the effect is studied and a concentration of the excess of neutral leading systems at low invariant masses (<~ 2 GeV/c^2) is observed, indicating that gluon jets might have an additional hitherto undetected fragmentation mode via a two-gluon system. This could be an indication of a possible production of gluonic states as predicted by QCD.Comment: 19 pages, 6 figures, Accepted by Phys. Lett.

    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

    Available evidence and outcome of off-label use of rituximab in clinical practice

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    Purpose: To analyze the therapeutic indications for off-label use of rituximab, the available evidence for its use, the outcomes, and the cost. Methods: This was a retrospective analysis of patients treated with rituximab for off-label indications from January 2007 to December 2009 in two tertiary hospitals. Information on patient characteristics, medical conditions, and therapeutic responses was collected from medical records. Available evidence for the efficacy of rituximab in each condition was reviewed, and the cost of treatment was calculated. Results: A total of 101 cases of off-label rituximab use were analyzed. The median age of the patients involved was 53 [interquartile range (IQR) 37.5-68.0] years; 55.4 % were women. The indications for prescribing rituximab were primarily hematological diseases (46 %), systemic connective tissue disorders (27 %), and kidney diseases (20 %). Available evidence supporting rituximab treatment for these indications mainly came from individual cohort studies (53.5 % of cases) and case series (25.7 %). The short-term outcome (median 3 months, IQR 2-4 months) was a complete response in 38 % of cases and partial response in 32.6 %. The highest short-term responses were observed for systemic lupus erythematosus and membranous glomerulonephritis, and the lowest was for neuromyelitis optica, idiopathic thrombocytopenic purpura, and miscellaneous indications. Some response was maintained in long-term follow-up (median 23 months IQR 12-30months) in 69.2%of patients showing a short-term response. Median cost per patient was 5,187.5 (IQR 5,187.5-7,781.3). Conclusions: In our study, off-label rituximab was mainly used for the treatment of hematological, kidney, and systemic connective tissue disorders, and the response among our patient cohort was variable depending on the specific disease. The level of evidence supporting the use of rituximab for these indications was low and the cost was very high. We conclude that more clinical trials on the off-label use of rituximab are needed, although these may be difficult to conduct in some rare diseases. Data from observational studies may provide useful information to assist prescribing in clinical practice
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