Differential ambiguity reduces grouping of metastable objects

Two coaxial, ambiguously rotating objects tend to be perceived as corotating. Such grouping could be the consequence of bottom-up, cooperative interactions between the stimuli, or the top-down selection of object properties consistent with a model of the objects or scene. However, we find that the coupling between an ambiguous and unambiguous object is sharply reduced, presenting a challenge for both explanations of grouping. We describe experiments that support the idea that top-down feedback is necessary to select and stabilize a perceptual interpretation for ambiguous figures. Reduced coupling between objects of differing ambiguity can be explained if the feedback is global and proportional to ambiguity.     

Imaging characteristics of an amorphous silicon flat-panel detector for digital chest radiography

PURPOSE: To evaluate the imaging characteristics of an amorphous silicon flat-panel detector (FPD) for digital chest radiography. MATERIALS AND METHODS: The 41 x 41-cm digital FPD is constructed on a single monolithic glass substrate with a structured cesium iodide scintillator layer and an amorphous silicon thin-film transistor array for image readout. Basic imaging characteristics of the FPD and associated image processing system were assessed on acquired images, including linearity, repeatability, uniformity of response, modulation transfer function (MTF), noise power spectrum, detective quantum efficiency (DQE), contrast sensitivity, and scatter content. Results with the FPD system were compared to those with a storage phosphor computed radiography (CR) system. RESULTS: Images obtained with the FPD demonstrated excellent uniformity, repeatability, and linearity, as well as MTF and DQE that were superior to those with the storage phosphor CR system. The contrast and scatter content of images acquired with the FPD were equivalent to those acquired with the storage phosphor system. CONCLUSION: The FPD provides radiographic images with excellent inherent physical image quality.     

Specific Unwillingness to Donate Eyes: The Impact of Disfigurement,Knowledge and Procurement on Corneal Donation

Although willingness, attitudes and beliefs surrounding solid‐organ donation have been extensively investigated, much less is known about corneal donation. Despite evidence that a substantial number of families who agree to multiorgan donation also specifically refuse corneal donation, it is unclear why this occurs and what can be done to increase rates of corneal donation. We conducted a survey of 371 Australian adults regarding their views on corneal donation. Although willingness to donate corneas generally reflected a person's willingness to donate all of one's organs, unwillingness to donate corneas appeared to be due to other factors. Specifically, decisions not to donate appear to be driven by a range of concerns surrounding disfigurement. The survey also provides eye banks with reassurance about the acceptability of whole globe procurement, and recognition that research into blindness is a highly valued part of corneal donation. Finally, the survey identifies that many individuals see benefit in having their family engaged in the decision‐making process, suggesting that decisions about donation are more complex than a simple appeal to the autonomy of the deceased.     

A knowledge management tool for public health: health-evidence.ca

Background

The ultimate goal of knowledge translation and exchange (KTE) activities is to facilitate incorporation of research knowledge into program and policy development decision making. Evidence-informed decision making involves translation of the best available evidence from a systematically collected, appraised, and analyzed body of knowledge. Knowledge management (KM) is emerging as a key factor contributing to the realization of evidence-informed public health decision making. The goal of health-evidence.ca is to promote evidence-informed public health decision making through facilitation of decision maker access to, retrieval, and use of the best available synthesized research evidence evaluating the effectiveness of public health interventions.

Methods

The systematic reviews that populate health evidence.ca are identified through an extensive search (1985-present) of 7 electronic databases: MEDLINE, EMBASE, CINAHL, PsycINFO, Sociological Abstracts, BIOSIS, and SportDiscus; handsearching of over 20 journals; and reference list searches of all relevant reviews. Reviews are assessed for relevance and quality by two independent reviewers. Commonly-used public health terms are used to assign key words to each review, and project staff members compose short summaries highlighting results and implications for policy and practice.

Results

As of June 2010, there are 1913 reviews in the health-evidence.ca registry in 21 public health and health promotion topic areas. Of these, 78% have been assessed as being of strong or moderate methodological quality. Health-evidence.ca receives approximately 35,000 visits per year, 20,596 of which are unique visitors, representing approximately 100 visits per day. Just under half of all visitors return to the site, with the average user spending six minutes and visiting seven pages per visit. Public health nurses, program managers, health promotion workers, researchers, and program coordinators are among the largest groups of registered users, followed by librarians, dieticians, medical officers of health, and nutritionists. The majority of users (67%) access the website from direct traffic (e.g., have the health-evidence.ca webpage bookmarked, or type it directly into their browser).

Conclusions

Consistent use of health-evidence.ca and particularly the searching for reviews that correspond with current public health priorities illustrates that health-evidence.ca may be playing an important role in achieving evidence-informed public health decision making.     

Facilitating access to pre-processed research evidence in public health

Background  

Evidence-informed decision making is accepted in Canada and worldwide as necessary for the provision of effective health services. This process involves: 1) clearly articulating a practice-based issue; 2) searching for and accessing relevant evidence; 3) appraising methodological rigor and choosing the most synthesized evidence of the highest quality and relevance to the practice issue and setting that is available; and 4) extracting, interpreting, and translating knowledge, in light of the local context and resources, into practice, program and policy decisions. While the public health sector in Canada is working toward evidence-informed decision making, considerable barriers, including efficient access to synthesized resources, exist.     

Small proportions: what to report for confidence intervals?

The original article to which this Erratum refers was published in Pharmacoepidemiology and Drug Safety 2005; 14: 239–247.     

Urban epizootic of rabies in Mexico: epidemiology and impact of animal bite injuries.

From 1 July 1987 to 31 December 1988, a total of 317 animals (91% of which were dogs) were confirmed to have rabies in Hermosillo, Mexico. The median age of rabid dogs was 1 year, 69% were male, and 98% were owned. The epizootic started in the southern areas of the city, rapidly involved the entire city, and persisted mainly in lower socioeconomic status areas. The area of the city and mean household size were significant predictor variables for the population density of rabid dogs around household clusters (Poisson linear regression, P < 0.001 and P = 0.03, resp). Approximately 2.5% of city residents were bitten by dogs in 1987, with the rate of reported dog bite injuries being positively correlated with mean household size and the proportion of households that owned dogs. Visits to the city health centre for evaluation of possible exposures to rabies increased by 135% after the start of the epizootic; approximately 273 per 100,000 city residents were administered a full or partial course of rabies post-exposure prophylaxis in 1987. Children were at greatest risk for exposures to rabies, accounting for 60% of all reported animal bite injuries evaluated at the health centre. Also they were more likely than older persons to have received bite injuries to the head, face, and neck (odds ratio = 21.6, 95% confidence interval = 5.4, 186.5).     

Effects and Clinical Significance of GII.4 Sydney Norovirus,United States, 2012–2013

During 2012, global detection of a new norovirus (NoV) strain, GII.4 Sydney, raised concerns about its potential effect in the United States. We analyzed data from NoV outbreaks in 5 states and emergency department visits for gastrointestinal illness in 1 state during the 2012–13 season and compared the data with those of previous seasons. During August 2012–April 2013, a total of 637 NoV outbreaks were reported compared with 536 and 432 in 2011–2012 and 2010–2011 during the same period. The proportion of outbreaks attributed to GII.4 Sydney increased from 8% in September 2012 to 82% in March 2013. The increase in emergency department visits for gastrointestinal illness during the 2012–13 season was similar to that of previous seasons. GII.4 Sydney has become the predominant US NoV outbreak strain during the 2012–13 season, but its emergence did not cause outbreak activity to substantially increase from that of previous seasons.