130 research outputs found
The Computation of Surface Lightness in Simple and Complex Scenes
The present thesis examined how reflectance properties and the complexity of surface mesostructure (small-scale surface relief) influence perceived lightness in centresurround displays. Chapters 2 and 3 evaluated the role of surface relief, gloss, and interreflections on lightness constancy, which was examined across changes in background albedo and illumination level. For surfaces with visible mesostructure (“rocky” surfaces), lightness constancy across changes in background albedo was better for targets embedded in glossy versus matte surfaces. However, this improved lightness constancy for gloss was not observed when illumination varied. Control experiments compared the matte and glossy rocky surrounds to two control displays, which matched either pixel histograms or a phase-scrambled power spectrum. Lightness constancy was improved for rocky glossy displays over the histogram-matched displays, but not compared to phase-scrambled variants of these images with equated power spectrums. The results were similar for surfaces rendered with 1, 2, 3 and 4 interreflections. These results suggest that lightness perception in complex centre-surround displays can be explained by the distribution of contrast across space and scale, independently of explicit information about surface shading or specularity. The results for surfaces without surface relief (“homogeneous” surfaces) differed qualitatively to rocky surfaces, exhibiting abrupt steps in perceived lightness at points at which the targets transitioned from being increments to decrements. Chapter 4 examined whether homogeneous displays evoke more complex mid-level representations similar to conditions of transparency. Matching target lightness in a homogeneous display to that in a textured or rocky display required varying both lightness and transmittance of the test patch on the textured display to obtain the most satisfactory matches. However, transmittance was only varied to match the contrast of targets against homogeneous surrounds, and not to explicitly match the amount of transparency perceived in the displays. The results suggest perceived target-surround edge contrast differs between homogeneous and textured displays. Varying the mid-level property of transparency in textured displays provides a natural means for equating both target lightness and the unique appearance of the edge contrast in homogeneous displays
Workshop Report: Concepts and methods in the economics of nutrition - Gateways to better economic evaluation of nutrition interventions
Improving health through better nutrition of the population may contribute to enhanced efficiency and sustainability of healthcare systems. A recent expert meeting investigated in detail a number of methodological aspects related to the discipline of nutrition economics. The role of nutrition in health maintenance and in the prevention of non-communicable diseases is now generally recognised. However, the main scope of those seeking to contain healthcare expenditures tends to focus on the management of existing chronic diseases. Identifying additional relevant dimensions to measure and the context of use will become increasingly important in selecting and developing outcome measurements for nutrition interventions. The translation of nutrition-related research data into public health guidance raises the challenging issue of carrying out more pragmatic trials in many areas where these would generate the most useful evidence for health policy decision-making. Nutrition exemplifies all the types of interventions and policy which need evaluating across the health field. There is a need to start actively engaging key stakeholders in order to collect data and to widen health technology assessment approaches for achieving a policy shift from evidence-based medicine to evidence-based decision-making in the field of nutrition
Nutrition economics – characterising the economic and health impact of nutrition
There is a new merging of health economics and nutrition disciplines to assess the impact of diet on health and disease prevention and to characterise the health and economic aspects of specific changes in nutritional behaviour and nutrition recommendations. A rationale exists for developing the field of nutrition economics which could offer a better understanding of both nutrition, in the context of having a significant influence on health outcomes, and economics, in order to estimate the absolute and relative monetary impact of health measures. For this purpose, an expert meeting assessed questions aimed at clarifying the scope and identifying the key issues that should be taken into consideration in developing nutrition economics as a discipline that could potentially address important questions. We propose a first multidisciplinary outline for understanding the principles and particular characteristics of this emerging field. We summarise here the concepts and the observations of workshop participants and propose a basic setting for nutrition economics and health outcomes research as a novel discipline to support nutrition, health economics and health policy development in an evidence and health-benefit-based manner
The VIMOS VLT Deep Survey: The build-up of the colour-density relation
We investigate the redshift and luminosity evolution of the galaxy
colour-density relation using the data from the First Epoch VIMOS-VLT Deep
Survey (VVDS). The size (6582 galaxies), depth (I_AB<=24) and redshift sampling
rate of the survey enable us to reconstruct the 3D galaxy environment on
relatively local scales (R=5 Mpc) up to z~1.5. Particular attention has been
devoted to calibrate a density reconstruction scheme, which factors out survey
selection effects and reproduces in an unbiased way the underlying `real'
galaxy environment. While at lower redshift we confirm the existence of a steep
colour-density relation, with the fraction of the reddest(/bluest) galaxies of
the same luminosity increasing(/decreasing) as a function of density, this
trend progressively disappears in the highest redshift bins investigated. The
rest frame u*-g' colour-magnitude diagram shows a bimodal pattern in both low
and high density environments up to z~1.5. We find that the bimodal
distribution is not universal but strongly depends upon environment: at lower
redshifts the colour-magnitude diagrams in low and high density regions are
significantly different while the progressive weakening of the colour-density
relation causes the two bimodal distributions to nearly mirror each other in
the highest redshift bin investigated. Both the colour-density and the
colour-magnitude-density relations appear to be a transient, cumulative product
of genetic and environmental factors operating over at least a period of 9 Gyr.
These findings support an evolutionary scenario in which star formation/gas
depletion processes are accelerated in more luminous objects and in high
density environments: star formation activity is shifting with cosmic time
towards lower luminosity (downsizing), and out of high density environments.Comment: 17 pages, 10 figures, figures added, accepted by A&
The LAGUNA design study- towards giant liquid based underground detectors for neutrino physics and astrophysics and proton decay searches
The feasibility of a next generation neutrino observatory in Europe is being
considered within the LAGUNA design study. To accommodate giant neutrino
detectors and shield them from cosmic rays, a new very large underground
infrastructure is required. Seven potential candidate sites in different parts
of Europe and at several distances from CERN are being studied: Boulby (UK),
Canfranc (Spain), Fr\'ejus (France/Italy), Pyh\"asalmi (Finland),
Polkowice-Sieroszowice (Poland), Slanic (Romania) and Umbria (Italy). The
design study aims at the comprehensive and coordinated technical assessment of
each site, at a coherent cost estimation, and at a prioritization of the sites
within the summer 2010.Comment: 5 pages, contribution to the Workshop "European Strategy for Future
Neutrino Physics", CERN, Oct. 200
Health care costs for the treatment of breast cancer recurrent events: estimates from a UK-based patient-level analysis
Cost pressures and the need to demonstrate cost-effectiveness of new interventions require consideration of the costs of treating disease. This study presents analyses of resource use data covering 199 postmenopausal women who experienced a breast cancer recurrent event between 1991 and 2004 and were treated at the Western General Hospital, Edinburgh. Aggregate (5-year) treatment costs for alternative recurrent events were estimated, as well as the annual costs incurred by patients experiencing contralateral, locoregional, or distant recurrence, who remained alive without further recurrence for a year. The 95% confidence intervals for the 5-year costs of recurrence ranged from £10 000 to £37 000 for locoregional recurrence, and £14 500–£20 000 for distant recurrence. No evidence of significant variations in these costs across time periods between 1991 and 2004 was identified. Annual costs for patients remaining in the same health state showed high initial costs for contralateral and locoregional recurrence, with low costs in subsequent years, while costs associated with distant recurrence declined at a slower rate and plateaued at 4–5 years post-diagnosis. The cost estimates presented in this paper not only inform the magnitude of the resource consequences of breast cancer recurrences, but they are also better suited to informing cost-effectiveness analyses, which have a far greater role in allocating health-care resources
Identification of nine sequence types of the 16S rRNA genes of Campylobacter jejuni subsp. jejuni isolated from broilers
<p>Abstract</p> <p>Background</p> <p>Campylobacter is the most commonly reported bacterial cause of enteritis in humans in the EU Member States and other industrialized countries. One significant source of infection is broilers and consumption of undercooked broiler meat. <it>Campylobacter jejuni </it>is the <it>Campylobacter </it>sp. predominantly found in infected humans and colonized broilers. Sequence analysis of the 16S rRNA gene is very useful for identification of bacteria to genus and species level. The objectives in this study were to determine the degree of intraspecific variation in the 16S rRNA genes of <it>C. jejuni </it>and <it>C. coli </it>and to determine whether the 16S rRNA sequence types correlated with genotypes generated by PFGE analysis of <it>Sma</it>I restricted genomic DNA of the strains.</p> <p>Methods</p> <p>The 16S rRNA genes of 45 strains of <it>C. jejuni </it>and two <it>C. coli </it>strains isolated from broilers were sequenced and compared with 16S rRNA sequences retrieved from the Ribosomal Database Project or GenBank. The strains were also genotyped by PFGE after digestion with <it>Sma</it>I.</p> <p>Results</p> <p>Sequence analyses of the 16S rRNA genes revealed nine sequence types of the <it>Campylobacter </it>strains and the similarities between the different sequence types were in the range 99.6–99.9%. The number of nucleotide substitutions varied between one and six among the nine 16S rRNA sequence types. One of the nine 16S rRNA sequence profiles was common to 12 of the strains from our study and two of these were identified as <it>Campylobacter coli </it>by PCR/REA. The other 10 strains were identified as <it>Campylobacter jejuni</it>. Five of the nine sequence types were also found among the <it>Campylobacter </it>sequences deposited in GenBank. The three 16S rRNA genes in the analysed strains were identical within each individual strain for all 47 strains.</p> <p>Conclusion</p> <p><it>C. jejuni </it>and <it>C. coli </it>seem to lack polymorphisms in their 16S rRNA gene, but phylogenetic analysis based on 16S rRNA sequences was not always sufficient for differentiation between <it>C. jejuni </it>and <it>C. coli</it>. The strains were grouped in two major clusters according to 16S rRNA, one cluster with only <it>C. jejuni </it>and the other with both <it>C. jejuni </it>and <it>C. coli</it>. Genotyping of the 47 strains by PFGE after digestion with <it>Sma</it>I resulted in 22 subtypes. A potential correlation was found between the <it>Sma</it>I profiles and the 16S rRNA sequences, as a certain <it>Sma</it>I type only appeared in one of the two major phylogenetic groups.</p
Proteins from Avastin® (bevacizumab) Show Tyrosine Nitrations for which the Consequences Are Completely Unclear
Avastin® (bevacizumab) is a protein drug widely used for cancer treatment although its further use is questionable due to serious side effects reported. As no systematic proteomic study on posttranslational modifications (PTMs) was reported so far, it was the aim of the current study to use a gel-based proteomics method for determination of Avastin®-protein(s)
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