AbstractRectal injuries are rare sequelae of blunt force abdominal trauma and are notorious for delayed recognition with resulting high morbidity and mortality. The management of traumatic colorectal ...injury is mired in old dogma and until recently mandated faecal diversion. Here we present a case of extraperitoneal rectal perforation successfully managed conservatively following blunt trauma.
A fast ionization chamber for fission cross-section measurements at n_TOF Calviani, M.; Cennini, P.; Karadimos, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2008, Letnik:
594, Številka:
2
Journal Article
Recenzirano
An ionization chamber with fast timing properties was built at CERN for measuring fission cross-sections of minor actinides at the n_TOF neutron beam. The design of this new chamber and of the ...front-end electronics was optimized to match the innovative features of the n_TOF facility, in particular the high instantaneous neutron flux and low background. For the most radioactive isotopes, a special version of the chamber, designed according to the ISO2919 standards, was built in order to comply with the radioprotection requirements at CERN. The detector and front-end electronics are here described, together with the simulated and measured response to fission fragments and α-particles. The performances of the chamber during the first measurement campaign at n_TOF are presented, focusing in particular on the fast time response, the good background rejection capability, low-background and high detection efficiency.
To satisfy the world's constantly increasing demand for energy, a suitable mix of different energy sources has to be devised. In this scenario, an important role could be played by nuclear energy, ...provided that major safety, waste and proliferation issues affecting current nuclear reactors are satisfactorily addressed. To this purpose, a large effort has been under way for a few years towards the development of advanced nuclear systems with the aim of closing the fuel cycle. Generation IV reactors, with full or partial waste recycling capability, accelerator driven systems, as well as new fuel cycles are the main options being investigated. The design of advanced systems requires improvements in basic nuclear data, such as cross-sections for neutron-induced reactions on actinides. In this paper, the main concepts of advanced reactor systems are described, together with the related needs of new and accurate nuclear data. The present activity in this field at the neutron facility n_TOF at CERN is discussed.
Neutron-induced reaction cross-sections of actinides have been obtained at CERN n_TOF to improve the accuracy of basic data needed for the design of advanced nuclear energy systems.
The n_TOF Collaboration has built and commissioned a high-performance detector for
(
n
,
γ
)
measurements called the Total Absorption Calorimeter (TAC). The TAC was especially designed for measuring ...neutron capture cross-sections of low-mass and/or radioactive samples with the accuracy required for nuclear technology and stellar nucleosynthesis. We present a detailed description of the TAC and discuss its overall performance in terms of energy and time resolution, background discrimination, detection efficiency and neutron sensitivity.
In this study, we attempt to optimize the use of strobilurin fungicides by testing the efficacy of azoxystrobin, kresoxim-methyl, pyraclostrobin, and trifloxystrobin under field conditions, by ...testing for the most efficient partners in fungicide mixtures, and by testing control efficacy of strobilurin fungicides applied at several application times to determine the better options for disease management. Results showed that trifloxystrobin was the most efficient strobilurin fungicide, followed by pyraclostrobin. Azoxystrobin provided a modest to poor control efficacy, whereas kresoxim-methyl provided only poor disease control efficacy. Mixtures of azoxystrobin and trifloxystrobin with either chlorothalonil or maneb and difenoconazole or flutriafol were tested for their efficacy in controlling the disease. The results showed that the azoxystrobin-containing mixtures provided significantly better control compared with that obtained by single applications of each mixture component. The mixtures of trifloxystrobin with maneb or with difenoconazole or flutriafol provided control efficacy similar to that obtained by single applications of trifloxystrobin, whereas the mixture of trifloxystrobin and chlorothalonil provided significantly lower control efficacy compared with the other trifloxystrobin-containing mixtures tested. For both strobilurin fungicides tested, the calculated ratio between the observed and the expected control efficacy ranged around the value of 1, suggesting additive interactions between the mixtures' components. To determine the most appropriate time for strobilurin fungicides application, trifloxystrobin was applied as the first two, the middle two, or the final two consecutive treatments of six fungicide applications. The remaining fungicide treatments in the spray schedules were carried out by applying the systemic fungicide difenoconazole. Results showed that a higher control efficacy was obtained when trifloxystrobin was applied in either of the earlier applications.
Analysis of the FIC detector data at the n_TOF facility Karadimos, D.; Vlastou, R.; Ioannides, K. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
08/2010, Letnik:
268, Številka:
16
Journal Article
Recenzirano
Fission cross-section measurements with the Fast Ionization Chamber (FIC) at the CERN n_TOF facility were challenged by intense signals due to γ-rays and ultra-relativistic particles from the impact ...of the 20
GeV proton pulses on the neutron spallation target. A method for analyzing the data taken with Flash Analog to Digital Converters (FADC) was developed to treat these problems in an automated way to provide a reliable background subtraction and a fit routine for identifying fission events even at high energies. The analysis is illustrated at the example of the fission cross-section of
238U relative to that of
235U in the energy range from 40
keV to 300
MeV.
Powdery mildew, caused by
Erysiphe betae, is a major foliar disease of sugar beet in areas with dry and relatively warm weather, worldwide. Four fungicides—azoxystrobin, kresoxim-methyl, ...pyraclostrobin and trifloxystrobin—were evaluated, at three application doses (100, 150 and 200
g
a.i.
ha
−1), for control of the disease. Trifloxystrobin and kresoxim-methyl were the most effective with control efficacy values higher than 94% compared to the control treatment even when applied at the lowest application dose of 100
g
a.i.
ha
−1. Azoxystrobin and pyraclostrobin had poor to modest activity against the disease even at the highest application dose. Disease severity, in terms of area under the disease progress curve values, was significantly correlated with decreased root yield, while no significant correlation existed between disease severity and sugar content of the roots or sucrose yield. In addition, the efficacy of tank mixtures of each of the strobilurin fungicides applied at 100
g
a.i.
ha
−1 with either of two sterol demethylation-inhibiting fungicides, difenoconazole and cyproconazole applied at 62.5 and 25
g
a.i.
ha
−1, respectively, was evaluated. The mixtures of azoxystrobin and pyraclostrobin with either difenoconazole or cyproconazole provided better control efficacy compared to single applications of each mixture partner, while the tank mixtures of trifloxystrobin and kresoxim-methyl with either difenoconazole or cyproconazole provided better control efficacy compared to single applications of difenoconazole or cyproconazole and similar control efficacy compared to that obtained by single applications of the strobilurin fungicides.
Twenty commercial sugar beet varieties were grown at two sites in central Greece during the 2001 growing season (March to October), in a completely randomized block design with three replications. ...Carbon isotope discrimination (Δ) in sugar beet leaves was found to be affected by site and marginally by variety. No relation was found between fresh root yield and Δ, but significant correlations were found between Δ and sucrose content (positive) and between Δ and root α-amino-N (negative). Also, the harvest index, determined at one site, was negatively correlated with Δ.
The ratio of the neutron-induced fission cross-sections of
243
Am and
235
U was measured in the energy range from 0.5 to 20 MeV with uncertainties of ≈ 4%. The experiment was performed at the CERN ...n_TOF facility using a fast ionization chamber. With the good counting statistics that could be achieved thanks to the high instantaneous flux and the low backgrounds, the present results are useful for resolving discrepancies in previous data sets and are important for future reactors with improved fuel burn-up.
PDF
