586 research outputs found
A Method to Determine the In-Air Spatial Spread of Clinical Electron Beams
We propose and analyze in detail a method to measure the in-air spatial
spread parameter of clinical electron beams. Measurements are performed at the
center of the beam and below the adjustable collimators sited in asymmetrical
configuration in order to avoid the distortions due to the presence of the
applicator. The main advantage of our procedure lies in the fact that the dose
profiles are fitted by means of a function which includes, additionally to the
Gaussian step usually considered, a background which takes care of the dose
produced by different mechanisms that the Gaussian model does not account for.
As a result, the spatial spread is obtained directly from the fitting procedure
and the accuracy permits a good determination of the angular spread. The way
the analysis is done is alternative to that followed by the usual methods based
on the evaluation of the penumbra width. Besides, the spatial spread found
shows the quadratic-cubic dependence with the distance to the source predicted
by the Fermi-Eyges theory. However, the corresponding values obtained for the
scattering power are differing from those quoted by ICRU nr. 35 by a factor ~2
or larger, what requires of a more detailed investigation.Comment: 11 pages, 5 Postscript figures, to be published in Medical Physic
arf3DS4: An Integrated Framework for Localization and Connectivity Analysis of fMRI Data
In standard fMRI analysis all voxels are tested in a massive univariate approach, that is, each voxel is tested independently. This requires stringent corrections for multiple comparisons to control the number of false positive tests (i.e., marking voxels as active while they are actually not). As a result, fMRI analyses may suffer from low power to detect activation, especially in studies with high levels of noise in the data, for example developmental or single-subject studies. Activated region fitting (ARF) yields a solution by modeling fMRI data by multiple Gaussian shaped regions. ARF only requires a small number of parameters and therefore has increased power to detect activation. If required, the estimated regions can be directly used as regions of interest in a functional connectivity analysis. ARF is implemented in the R package arf3DS4. In this paper ARF and its implementation are described and illustrated with an example
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Overview of the facility accident analysis for the U.S. Department of Energy Environmental Restoration and Waste Management Programmatic Environmental Impact Statement
An integrated risk-based approach has been developed to address the human health risks of radiological and chemical releases from potential facility accidents in support of the U.S. Department of Energy (DOE) Environmental Restoration and Waste Management (EM) Programmatic Environmental Impact Statement (PEIS). Accordingly, the facility accident analysis has been developed to allow risk-based comparisons of EM PEIS strategies for consolidating the storage and treatment of wastes at different sites throughout the country. The analysis has also been developed in accordance with the latest DOE guidance by considering the spectrum of accident scenarios that could occur in implementing the various actions evaluated in the EM PEIS. The individual waste storage and treatment operations and inventories at each site are specified by the functional requirements defined for each waste management alternative to be evaluated. For each alternative, the accident analysis determines the risk-dominant accident sequences and derives the source terms from the associated releases. This information is then used to perform health effects and risk calculations that are used to evaluate the various alternatives
Everyday experiences of people living with MCI or dementia:A scoping review
Background Increasing attention has been paid to the ‘voice’ of people living with MCI or dementia, but there is a lack of clarity about how everyday life is exercised, lived, and understood from this insider’s perspective. The current study aimed to explore and identify the everyday life experiences, challenges and facilitators, of home living individuals with MCI and dementia. Method Our study adopted a scoping review methodology, guided by the Joanna Briggs Institute Reviewers Manual. Eight databases were searched, resulting in 6345 records, of which 58 papers were included in the review. Only qualitative studies were included, published between 2011 and 2021. Analysis was done by descriptive content analysis. Result Included study characteristics are summarized in Table 1. Our findings were categorized into seven spheres of everyday life: experiences related to the condition, the self, relationships, activities, environment, health and social care, and public opinions [Figure 1, Table 2]. Results show the many disruptions and losses in everyday life and the ways people try to adapt to these changes. Highlighted in every area is the importance of reciprocal relationships and being engaged as citizens in the community in a meaningful way. Included studies showed no differences between groups in the impact on the experience of everyday life, such as between MCI and dementia. Conclusion This review shows that the change of focus from healthcare to all aspects of everyday life provides insight into the insider’s perspective of people living with dementia. The majority of included studies emphasize the social needs of people living with MCI or dementia. All areas of everyday life seem to be closely intertwined and reflect an socioecological model [1], [2], [3]. Furthermore, perhaps one of the defining aspects of MCI according to the current definition, that symptoms do not interfere with daily life, requires more nuance. More research is needed on factors that promote and impede the sense of reciprocity and belonging, as experienced by people living with MCI and dementia
Binomial level densities
It is shown that nuclear level densities in a finite space are described by a
continuous binomial function, determined by the first three moments of the
Hamiltonian, and the dimensionality of the underlying vector space.
Experimental values for Mn, Fe, and Ni are very well
reproduced by the binomial form, which turns out to be almost perfectly
approximated by Bethe's formula with backshift. A proof is given that binomial
densities reproduce the low moments of Hamiltonians of any rank: A strong form
of the famous central limit result of Mon and French. Conditions under which
the proof may be extended to the full spectrum are examined.Comment: 4 pages 2 figures Second version (previous not totally superseeded
Conditions of graphite precipitation in the volcanic-hosted deposits at Borrowdale (Cumbria, UK)
Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu
Highly deformed Ca configurations in Si + C
The possible occurrence of highly deformed configurations in the Ca
di-nuclear system formed in the Si + C reaction is investigated
by analyzing the spectra of emitted light charged particles. Both inclusive and
exclusive measurements of the heavy fragments (A 10) and their
associated light charged particles (protons and particles) have been
made at the IReS Strasbourg {\sc VIVITRON} Tandem facility at bombarding
energies of Si) = 112 MeV and 180 MeV by using the {\sc ICARE}
charged particle multidetector array. The energy spectra, velocity
distributions, and both in-plane and out-of-plane angular correlations of light
charged particles are compared to statistical-model calculations using a
consistent set of parameters with spin-dependent level densities. The analysis
suggests the onset of large nuclear deformation in Ca at high spin.Comment: 33 pages, 11 figure
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State-of-the-art software for window energy-efficiency rating and labeling
Measuring the thermal performance of windows in typical residential buildings is an expensive proposition. Not only is laboratory testing expensive, but each window manufacturer typically offers hundreds of individual products, each of which has different thermal performance properties. With over a thousand window manufacturers nationally, a testing-based rating system would be prohibitively expensive to the industry and to consumers. Beginning in the early 1990s, simulation software began to be used as part of a national program for rating window U-values. The rating program has since been expanded to include Solar Hear Gain Coefficients and is now being extended to annual energy performance. This paper describes four software packages available to the public from Lawrence Berkeley National Laboratory (LBNL). These software packages are used to evaluate window thermal performance: RESFEN (for evaluating annual energy costs), WINDOW (for calculating a product`s thermal performance properties), THERM (a preprocessor for WINDOW that determines two-dimensional heat-transfer effects), and Optics (a preprocessor for WINDOW`s glass database). Software not only offers a less expensive means than testing to evaluate window performance, it can also be used during the design process to help manufacturers produce windows that will meet target specifications. In addition, software can show small improvements in window performance that might not be detected in actual testing because of large uncertainties in test procedures
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