97 research outputs found
Adapting African Agriculture to Climate Change: Transforming Rural Livelihoods
This book summarizes the evidence from different African countries about the local impacts of climate change, and how farmers are coping with current climate risks. The different contributors show how agricultural systems in developing countries are affected by climate changes and how communities prepare and adapt to these changes
Fungal Infections in Neonatal Intensive Care
Neonates represent a unique and highly vulnerable patient population. Advances in medical technology have improved the survival and quality of life of newborns, particularly those with extreme prematurity or with congenital defects. Furthermore, immunologic immaturity and altered cutaneous barriers play some role in the vulnerability of neonates to nosocomial infections. In this context, the incidence of invasive fungal infections has increased significantly worldwide, representing an important infective complication in patients hospitalized in intensive care units. Invasive fungal infections in Neonatal Intensive Care Unit (NICUs) show high mortality; being species of Candida, the most isolates etiologic agents. The better prognosis of the patient is associated with the early diagnosis and fast treatment. However, guidelines to facilitate the optimal therapy choice for the treatment of neonatal fungal disease do not exist. The current antifungal agents that are available to treat fungemia among newborns and children are based on clinical trials in adults, since there are few comparative studies of antifungal agents in infants. The most commonly used drugs for the treatment of invasive fungal infections in neonates are classified in four different classes: polyene, azoles, analogs of pyrimidines and echinocandins
Time-of-flight and activation experiments on 147Pm and 171Tm for astrophysics
The neutron capture cross section of several key unstable isotopes acting as branching points in the s-process are crucial for stellar nucleosynthesis studies, but they are very challenging to measure due to the difficult production of sufficient sample material, the high activity of the resulting samples, and the actual (n,γ) measurement, for which high neutron fluxes and effective background rejection capabilities are required. As part of a new program to measure some of these important branching points, radioactive targets of 147Pm and 171Tm have been produced by irradiation of stable isotopes at the ILL high flux reactor. Neutron capture on 146Nd and 170Er at the reactor was followed by beta decay and the resulting matrix was purified via radiochemical separation at PSI. The radioactive targets have been used for time-of-flight measurements at the CERN n-TOF facility using the 19 and 185 m beam lines during 2014 and 2015. The capture cascades were detected using a set of four C6D6 scintillators, allowing to observe the associated neutron capture resonances. The results presented in this work are the first ever determination of the resonance capture cross section of 147Pm and 171Tm. Activation experiments on the same 147Pm and 171Tm targets with a high-intensity 30 keV quasi-Maxwellian flux of neutrons will be performed using the SARAF accelerator and the Liquid-Lithium Target (LiLiT) in order to extract the corresponding Maxwellian Average Cross Section (MACS). The status of these experiments and preliminary results will be presented and discussed as well
Characterization of the n-TOF EAR-2 neutron beam
The experimental area 2 (EAR-2) at CERNs neutron time-of-flight facility (n-TOF), which is operational since 2014, is designed and built as a short-distance complement to the experimental area 1 (EAR-1). The Parallel Plate Avalanche Counter (PPAC) monitor experiment was performed to characterize the beam prole and the shape of the neutron 'ux at EAR-2. The prompt γ-flash which is used for calibrating the time-of-flight at EAR-1 is not seen by PPAC at EAR-2, shedding light on the physical origin of this γ-flash
New measurement of the 242Pu(n,γ) cross section at n-TOF-EAR1 for MOX fuels : Preliminary results in the RRR
The spent fuel of current nuclear reactors contains fissile plutonium isotopes that can be combined with 238U to make mixed oxide (MOX) fuel. In this way the Pu from spent fuel is used in a new reactor cycle, contributing to the long-term sustainability of nuclear energy. The use of MOX fuels in thermal and fast reactors requires accurate capture and fission cross sections. For the particular case of 242Pu, the previous neutron capture cross section measurements were made in the 70's, providing an uncertainty of about 35% in the keV region. In this context, the Nuclear Energy Agency recommends in its "High Priority Request List" and its report WPEC-26 that the capture cross section of 242Pu should be measured with an accuracy of at least 7-12% in the neutron energy range between 500 eV and 500 keV. This work presents a brief description of the measurement performed at n-TOF-EAR1, the data reduction process and the first ToF capture measurement on this isotope in the last 40 years, providing preliminary individual resonance parameters beyond the current energy limits in the evaluations, as well as a preliminary set of average resonance parameters
Conteúdo de carbono orgânico em planossolo háplico sob sistemas de manejo do arroz irrigado
Farelo de licuri em dietas para alevinos de tambaqui (Colossoma Macropomum, Cuvier, 1818)
Radiative Neutron Capture Cross-Section Measurement of Ge Isotopes at n_TOF CERN Facility and Its Importance for Stellar Nucleosynthesis
This work was supported by the Austrian Science Fund FWF (J3503), the Adolf Messer Foundation (Germany), the UK Science and Facilities Council (ST/M006085/1), and the European Research Council ERC-2015-StG No. 677497. We also acknowledge the support of the National Science Centre, Poland, under the grant UMO-2016/22/M/ST2/00183, the MSMT of the Czech Republic and the Croatian Science Foundation under the project IP-2018-01-8570.This manuscript summarizes the results of radiative neutron capture cross-section measurements on two stable germanium isotopes, Ge-70 and Ge-73. Experiments were performed at the n_TOF facility at CERN via the time-of-flight technique, over a wide neutron energy range, for all stable germanium isotopes (70,72,73,74, and 76). Results for Ge-70 [Phys. Rev. C 100, 045804 (2019)] and Ge-73 [Phys. Lett. B 790, 458 (2019)] are already published. In the field of nuclear structure, such measurements allow to study excited levels close to the neutron binding energy and to obtain information on nuclear properties. In stellar nucleosynthesis research, neutron induced reactions on germanium are of importance for nucleosynthesis in the weak component of the slow neutron capture processes.Austrian Science Fund (FWF)
J3503Adolf Messer Foundation (Germany)UK Science and Facilities Council
ST/M006085/1European Research Council (ERC)European Commission
677497National Science Centre, Poland
UMO-2016/22/M/ST2/00183Ministry of Education, Youth & Sports - Czech RepublicCroatian Science Foundation
IP-2018-01-857
Intoxicação experimental por Simarouba versicolor (Simaroubaceae) em ovinos e indução de resistência ao consumo da planta
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