3,973 research outputs found
Thermoluminescent detectors applied in individual monitoring of radiation workers in Europe—a review based on the EURADOS questionnaire
Among the activities of EURADOS Working Group 2 formed by experts from several European countries is the harmonisation of individual monitoring as part of radiation protection of occupationally exposed persons. Here, we provide information about thermoluminescent detectors (TLDs) applied by the European dosimetric services and the dosimetric characteristics of dosemeters in which these detectors are applied. Among 91 services from 29 countries which responded to the EURADOS questionnaire, 61 apply dosemeters with TLDs for the determination of personal dose equivalent Hp(10) for photons and beta radiation, and 16 services use TLDs for neutron albedo dosemeters. Those most frequently used are standard lithium fluoride TLDs (mainly TLD-100, TLD-700, Polish MTS-N and MTS-7, Russian DTG-4), high-sensitive lithium fluoride (GR-200, MCP-N) and lithium borate TLDs. Some services use calcium sulphate and calcium fluoride detectors. For neutron dosimetry, most services apply pairs of LiF:Mg,Ti TLDs with 6Li and 7Li. The characteristics (energy response) of individual dosemeters are mainly related to the energy response of the detectors and filters applied. The construction of filters in dosemeters applied for measurements of Hp(10) and their energy response are also reviewe
A method for the deliberate and deliberative selection of policy instrument mixes for climate change adaptation
Policy instruments can help put climate adaptation plans into action. Here, we propose a method for the systematic assessment and selection of policy instruments for stimulating adaptation action. The multi-disciplinary set of six assessment criteria is derived from economics, policy, and legal studies. These criteria are specified for the purpose of climate adaptation by taking into account four challenges to the governance of climate adaptation: uncertainty, spatial diversity, controversy, and social complexity. The six criteria and four challenges are integrated into a step-wise method that enables the selection of instruments starting from a generic assessment and ending with a specific assessment of policy instrument mixes for the stimulation of a specific adaptation measure. We then apply the method to three examples of adaptation measures. The method’s merits lie in enabling deliberate choices through a holistic and comprehensive set of adaptation specific criteria, as well as deliberative choices by offering a stepwise method that structures an informed dialog on instrument selection. Although the method was created and applied by scientific experts, policy-makers can also use the method
Skin, Thermal and Umbilical Cord Care Practices for Neonates in Southern, Rural Zambia: A Qualitative Study
Background: In Choma District, southern Zambia, the neonatal mortality rate is approximately 40 per 1000 live births and, although the rate is decreasing, many deliveries take place outside of formal facilities. Understanding local practices during the postnatal period is essential for optimizing newborn care programs. Methods: We conducted 36 in-depth interviews, five focus groups and eight observational sessions with recently-delivered women, traditional birth attendants, and clinic and hospital staff from three sites, focusing on skin, thermal and cord care practices for newborns in the home. Results: Newborns were generally kept warm by application of hats and layers of clothing. While thermal protection is provided for preterm and small newborns, the practice of nighttime bathing with cold water was common. The vernix was considered important for the preterm newborn but dangerous for HIV-exposed infants. Mothers applied various substances to the skin and umbilical cord, with special practices for preterm infants. Applied substances included petroleum jelly, commercial baby lotion, cooking oil and breastmilk. The most common substances applied to the umbilical cord were powders made of roots, burnt gourds or ash. To ward off malevolent spirits, similar powders were reportedly placed directly into dermal incisions, especially in ill children. Conclusions: Thermal care for newborns is commonly practiced but co-exists with harmful practices. Locally appropriate behavior change interventions should aim to promote chlorhexidine in place of commonly-reported application of harmful substances to the skin and umbilical cord, reduce bathing of newborns at night, and address the immediate bathing of HIV-infected newborns
Memory effects induced by initial switching conditions
Initial-switching refers to the way in which the decay of an initially
confined state begins, as the barrier isolating it from the exterior is
relaxed. We study these effects in the context of Longhi's version of the
Fano-Anderson model. Most authors assume the sudden approximation where the
coupling is turned on instantaneously. We consider a finite rise time T, both
numerically and analytically. When the coupling is ramped up linearly over a
switching time T, we show that the asymptotic survival amplitude acquires a
phase T and is modulated by a factor (sin T)/T. Several other results relating
to the solution of the model are obtained. All site amplitudes have the same
decay constant during the exponential decay regime. In the asymptotic regime,
the amplitude and phase of decay oscillations depend on the initial-switching
profile, but the period does not.Comment: 12 pages, 10 figures, accepted by Phys. Rev.
A model for single electron decays from a strongly isolated quantum dot
Recent measurements of electron escape from a non-equilibrium charged quantum
dot are interpreted within a 2D separable model. The confining potential is
derived from 3D self-consistent Poisson-Thomas-Fermi calculations. It is found
that the sequence of decay lifetimes provides a sensitive test of the confining
potential and its dependence on electron occupation.Comment: 9 pages, 10 figure
Field-induced magnetic transitions in the quasi-two-dimensional heavy-fermion antiferromagnets Ce_{n}RhIn_{3n+2} (n=1 or 2)
We have measured the field-dependent heat capacity in the tetragonal
antiferromagnets CeRhIn and CeRhIn, both of which have an
enhanced value of the electronic specific heat coefficient
mJ/mol-Ce K above . For the specific heat data at zero
applied magnetic field are consistent with the existence of an anisotropic
spin-density wave opening a gap in the Fermi surface for CeRhIn while
CeRhIn shows behavior consistent with a simple antiferromagnetic
magnon. From these results, the magnetic structure, in a manner similar to the
crystal structure, appears more two-dimensional in CeRhIn than in
CeRhIn where only about 12% of the Fermi surface remains ungapped
relative to 92% for CeRhIn. When both compounds behave in a
manner expected for heavy fermion systems as both and the electronic
heat capacity decrease as field is applied. When the field is applied in the
tetragonal basal plane (), CeRhIn and CeRhIn have very
similar phase diagrams which contain both first- and second-order field-induced
magnetic transitions .Comment: 15 pages, 4 figure
Individual monitoring for internal exposures in Europe: Conclusions of an EURADOS action
Once the EC Directive 96/29 has been implemented into national regulation across Europe, the coordination of dosimetry laboratories for the monitoring of occupational exposures becomes the principal aim to achieve. Within this framework the European Radiation Dosimetry Group, EURADOS, carried out an Action on ‘Harmonisation of Individual Monitoring' (2000-2004) to promote coordination in the field of individual monitoring of occupational exposures throughout Europe. With reference to internal exposures, the main aims were the completion of a catalogue of internal dosimetry services and an inventory of methods and techniques used for individual monitoring at European internal dosimetry facilities. At the end of this EURADOS Action, a report was published in Radiation Protection Dosimetry in 2004. The information collected related to various topics: the equipments used for the measurement of internal exposures, calibration and sensitivity data, the methods applied for the assessment of internal doses, Quality Control procedures, Quality Assurance Programmes in the facilities and legal requirements. The information to be presented here will give a general overview of the actual status of individual monitoring for internal exposures in Europ
A compact and reconfigurable silicon nitride time-bin entanglement circuit
Photonic chip based time-bin entanglement has attracted significant attention
because of its potential for quantum communication and computation. Useful
time-bin entanglement systems must be able to generate, manipulate and analyze
entangled photons on a photonic chip for stable, scalable and reconfigurable
operation. Here we report the first time-bin entanglement photonic chip that
integrates time-bin generation, wavelength demultiplexing and entanglement
analysis. A two-photon interference fringe with an 88.4% visibility is measured
(without subtracting any noise), indicating the high performance of the chip.
Our approach, based on a silicon nitride photonic circuit, which combines the
low-loss characteristic of silica and tight integration features of silicon,
paves the way for scalable real-world quantum information processors.Comment: 4 pages, 5 figure
Angioscopic versus angiographic detection of initial detection of intimal dissection and intracoronary thrombus
AbstractObjectives. This study was undertaken to compare coronary angioscopy with angiography for the detection of intimal dissection and intracoronary thrombus.Background. It has been demonstrated previously that coronary angioscopy provides more intravascular detail than cineangiography. Both imaging methods have to be compared directly to assess the additional diagnostic value of angioscopy.Methods. The angiograms and videotapes of 52 patients who had undergone angioscopy were reviewed independently by two observers unaware of other findings. Classic angiographic definitions were used for dissection and thrombus. Angioscopic dissection was defined as visible cracks or fissures on the lumen surface or mobile protruding structures that are contiguous with the vessel wall. Angioscopic thrombus was defined as a red, white or mixed red and white intraluminal mass.Results. Angiography and angioscopy were in agreement in 40.4% of cases in the absence of thrombus and in 11.5% in the presence of thrombus. No fewer than 25 (48.1%) angioscopically observed thrombi remained undetected at angiography. With angioscopy as the standard, although the specificity of angiography for thrombus was 100%, sensitivity was very low at 19%. Angioscopic dissection was present in 40 patients (76.9%) versus angiographic dissection in 15 patients (28.8%). With regard to dissection, there was no correlation between the two imaging methods (rΦ= 0.15, p = 0.29).Conclusions. Coronary angiography underestimates the presence of intracoronary thrombus. Angioscopy and angiography are complementary techniques for detecting and grading intima1dissections
Applications of cyclotron based ion scattering
Ion scattering experiments have been performed with a 3-30 MeV AVF cyclotron. The wide range of available energies combined with proper beam handling allows many scattering techniques to perform. At first an example of ordinary Rutherford backscattering spectrometry will be demonstrated on model catalysts as studied in surface chemistry. High energy backscattering spectrometIy with 8.8 MeV He ions, which enhances the sensitivity for oxygen, has been applied to study the oxygen removal from corroded archaeological artefacts upon treatment with a H, plasma. Elastic recoil detection analysis will be shown feasible with He ions having incident energies between 10 and 15 MeV once combined with a thin film detector. The development of a setup for ion channeling experiments with the cyclotron is reported and first results promise to increase the angular resolution in lattice deformation studies
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