3,278 research outputs found

    Ostrácodos de Antofagasta de la Sierra, Puna catamarqueña, Argentina: su aporte a las interpretaciones paleolimnológicas del Holoceno

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    La Puna catamarqueña es un ámbito importante para los estudios paleoclimáticos. La concentración de agua y alimento en los humedales de esta zona hiperárida hace que los mismos tengan un rol esencial como centro de recursos para animales y las sociedades humanas. Por ello, el reconocimiento de los cambios paleoambientales tiene gran importancia en la comprensión de los patrones de ocupación humana durante el Holoceno relacionado con la disponibilidad de recursos. Se describen aquí asociaciones de ostrácodos actuales de humedales de Antofagasta de la Sierra, Puna catamarqueña, a fin de aportar datos para la interpretación de registros paleolimnológicos holocenos. Se analizaron las asociaciones de seis ambientes acuáticos diferentes por encima del piso de los 3400 msnm, lénticos y lóticos, considerando su heterogeneidad espacial. Este tipo de estudios son importantes para el avance de las investigaciones paleolimnológicas y paleoclimáticas de esta zona en donde la cantidad de datos disponibles es escasa. Entre las especies reconocidas, la especie de mayor distribución es Hemicypris panningi (Brehm). Habita vegas con abundante vegetación, tanto en facies de aguas estancadas como corrientes. Otra especie con una amplia distribución es Penthesilenula kohanga (Rossetti, Eagar y Martens). El análisis de las asociaciones recuperadas permite afirmar que la diversidad y composición específica de vegas de fondo de cuenca, lagunas y vegas de quebradas de altura (por encima de los 4000 msnm) presentan diferencias notables. Las vegas de fondo son los sitios más biodiversos, y están dominados por Hemicypris panningi y Penthesilenula kohanga. Por su parte, en las vegas de quebradas de altura, la biodiversidad es menor y se hallan presentes exclusivamente Heterocypris incongruens (Ramdohr) y Hemicypris panningi, mientras que en los ambientes lagunares se hallan presentes Paracandona sp. y Eucypris sp. aff. cecryphalium Cusminsky y Whatley.Simposio VIII: Paleoentomología y paleolimnología: objetivos particulares y comunesFacultad de Ciencias Naturales y Muse

    Leaf Anatomy and Photochemical Behaviour of Solanum lycopersicum

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    Plants can be exposed to ionising radiation not only in Space but also on Earth, due to specific technological applications or after nuclear disasters. The response of plants to ionising radiation depends on radiation quality/quantity and/or plant characteristics. In this paper, we analyse some growth traits, leaf anatomy, and ecophysiological features of plants of Solanum lycopersicum L. “Microtom” grown from seeds irradiated with increasing doses of X-rays (0.3, 10, 20, 50, and 100 Gy). Both juvenile and compound leaves from plants developed from irradiated and control seeds were analysed through light and epifluorescence microscopy. Digital image analysis allowed quantifying anatomical parameters to detect the occurrence of signs of structural damage. Fluorescence parameters and total photosynthetic pigment content were analysed to evaluate the functioning of the photosynthetic machinery. Radiation did not affect percentage and rate of seed germination. Plants from irradiated seeds accomplished the crop cycle and showed a more compact habitus. Dose-depended tendencies of variations occurred in phenolic content, while other leaf anatomical parameters did not show distinct trends after irradiation. The sporadic perturbations of leaf structure, observed during the vegetative phase, after high levels of radiation were not so severe as to induce any significant alterations in photosynthetic efficiency

    RenalGuard system in high-risk patients for contrast-induced acute kidney injury.

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    BACKGROUND: High urine flow rate (UFR) has been suggested as a target for effective prevention of contrast-induced acute kidney injury (CI-AKI). The RenalGuard therapy (saline infusion plus furosemide controlled by the RenalGuard system) facilitates the achievement of this target. METHODS: Four hundred consecutive patients with an estimated glomerular filtration rate ≤30 mL/min per 1.73 m(2) and/or a high predicted risk (according to the Mehran score ≥11 and/or the Gurm score >7%) treated by the RenalGuard therapy were analyzed. The primary end points were (1) the relationship between CI-AKI and UFR during preprocedural, intraprocedural, and postprocedural phases of the RenalGuard therapy and (2) the rate of acute pulmonary edema and impairment in electrolytes balance. RESULTS: Urine flow rate was significantly lower in the patients with CI-AKI in the preprocedural phase (208 ± 117 vs 283 ± 160 mL/h, P 0.32 mg/kg (HR 5.03, 95% CI 2.33-10.87, P < .001) were independent predictors of CI-AKI. Pulmonary edema occurred in 4 patients (1%). Potassium replacement was required in 16 patients (4%). No patients developed severe hypomagnesemia, hyponatremia, or hypernatremia. CONCLUSIONS: RenalGuard therapy is safe and effective in reaching high UFR. Mean intraprocedural UFR ≥450 mL/h should be the target for optimal CI-AKI prevention

    Can we predict development of impulsive-compulsive behaviours in Parkinson's disease?

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    OBJECTIVE: To determine clinical and structural imaging predictors of impulsive-compulsive behaviour (ICB) in de novo Parkinson's disease (PD). METHODS: From a cohort of 1116 subjects from the Parkinson's Progression Marker Initiative database, we created a subcohort of 42 de novo PD without ICB at baseline with available 3T MRI and who developed ICB during follow-up. PD-ICB were matched for age, gender and disease duration to 42 patients with PD without ICB over follow-up (PD-no-ICB) and 42 healthy controls (HCs). Baseline demographic and clinical predictors of ICB were analysed. For the longitudinal neuroimaging analysis, we selected 27 patients with PD-ICB with available neuroimaging after ICB onset, who were matched with 32 PD-no-ICB and 35 HCs. Baseline and longitudinal structural differences were compared using voxel-based morphometry and voxel-based quantification. RESULTS: People who went on to develop ICB had more severe anxiety, worse autonomic and global cognitive functions and were more likely to have rapid eye movement sleep behaviour disorder. Logistic regression confirmed that worse autonomic and cognitive functions were predictors of ICB. We could not find any morphological feature on baseline MRI that predicted later onset of ICB. When comparing PD groups at follow-up, a small region of increased atrophy in the anterior limb of the left internal capsule adjacent to the head of the left caudate nucleus was found in PD-ICB, but not surviving correction for multiple comparisons. CONCLUSIONS: Worse autonomic and cognitive functions predict development of ICB at the time of PD diagnosis. Structural imaging fails to identify morphological features associated with the development of ICB

    A global fit to determine the pseudoscalar mixing angle and the gluonium content of the eta' meson

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    We update the values of the eta-eta' mixing angle and of the eta' gluonium content by fitting our measurement R_phi = BR(phi to eta' gamma)/ BR(phi to eta gamma) together with several vector meson radiative decays to pseudoscalars (V to P gamma), pseudoscalar mesons radiative decays to vectors (P to V gamma) and the eta' to gamma gamma, pi^0 to gamma gamma widths. From the fit we extract a gluonium fraction of Z^2_G = 0.12 +- 0.04, the pseudoscalar mixing angle psi_P = (40.4 +- 0.6) degree and the phi-omega mixing angle psi_V = (3.32 +- 0.09) degree. Z^2_G and psi_P are fairly consistent with those previously published. We also evaluate the impact on the eta' gluonium content determination of future experimental improvements of the eta' branching ratios and decay width.Comment: 13 pages, 7 figures to submit to JHE

    Measurement of the neutron detection efficiency of a 80% absorber - 20% scintillating fibers calorimeter

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    The neutron detection efficiency of a sampling calorimeter made of 1 mm diameter scintillating fibers embedded in a lead/bismuth structure has been measured at the neutron beam of the The Svedberg Laboratory at Uppsala. A significant enhancement of the detection efficiency with respect to a bulk organic scintillator detector with the same thickness is observed.Comment: 10 pages, 7 figure

    Measurement of neutron detection efficiency between 22 and 174 MeV using two different kinds of Pb-scintillating fiber sampling calorimeters

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    We exposed a prototype of the lead-scintillating fiber KLOE calorimeter to neutron beam of 21, 46 and 174 MeV at The Svedberg Laboratory, Uppsala, to study its neutron detection efficiency. This has been found larger than what expected considering the scintillator thickness of the prototype. %To check our method, we measured also the neutron %detection efficiency of a 5 cm thick NE110 scintillator. We show preliminary measurement carried out with a different prototype with a larger lead/fiber ratio, which proves the relevance of passive material to neutron detection efficiency in this kind of calorimeters
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