Searchability of Networks

We investigate the searchability of complex systems in terms of their interconnectedness. Associating searchability with the number and size of branch points along the paths between the nodes, we find that scale-free networks are relatively difficult to search, and thus that the abundance of scale-free networks in nature and society may reflect an attempt to protect local areas in a highly interconnected network from nonrelated communication. In fact, starting from a random node, real-world networks with higher order organization like modular or hierarchical structure are even more difficult to navigate than random scale-free networks. The searchability at the node level opens the possibility for a generalized hierarchy measure that captures both the hierarchy in the usual terms of trees as in military structures, and the intrinsic hierarchical nature of topological hierarchies for scale-free networks as in the Internet.Comment: 9 pages, 10 figure

A simple model for self organization of bipartite networks

We suggest a minimalistic model for directed networks and suggest an application to injection and merging of magnetic field lines. We obtain a network of connected donor and acceptor vertices with degree distribution $1/s^2$, and with dynamical reconnection events of size $\Delta s$ occurring with frequency that scale as $1/\Delta s^3$. This suggest that the model is in the same universality class as the model for self organization in the solar atmosphere suggested by Hughes et al.(PRL {\bf 90} 131101)

Do the clothes make the criminal? The influence of clothing match on identification accuracy in showups

Showups, a single suspect identification, are thought to be a more suggestive procedure than traditional lineups by the U.S. Supreme Court and social science researchers. Previous research typically finds that a clothing match in showup identifications increases false identifications. However, these experiments do not allow for a determination of whether this increase arises from a change in response bias, reduced discriminability, or both. In the present study, participants viewed a mock crime video and made a showup identification with either a clothing match or mismatch. Contrary to prior research, the best discriminability occurred when the guilty and innocent suspects wore clothing that matched the clothing worn during the crime. A clothing match also resulted in a more liberal response bias. The results are consistent with the principle of encoding specificity and the outshining hypothesis, as instantiated in the item, context, ensemble theory. Practical implications are discussed

Heat, Heat Waves, and Hospital Admissions among the Elderly in the United States, 1992–2006

Background: Heat-wave frequency, intensity, and duration are increasing with global climate change. The association between heat and mortality in the elderly is well documented, but less is known regarding associations with hospital admissions. Objectives: Our goal was to determine associations between moderate and extreme heat, heat waves, and hospital admissions for nonaccidental causes among Medicare beneficiaries ≥ 65 years of age in 114 cities across five U.S. climate zones. Methods: We used Medicare inpatient billing records and city-specific data on temperature, humidity, and ozone from 1992 through 2006 in a time-stratified case-crossover design to estimate the association between hospitalization and moderate [90th percentile of apparent temperature (AT)] and extreme (99th percentile of AT) heat and heat waves (AT above the 95th percentile over 2–8 days). In sensitivity analyses, we additionally considered confounding by ozone and holidays, different temperature metrics, and alternate models of the exposure–response relationship. Results: Associations between moderate heat and hospital admissions were minimal, but extreme heat was associated with a 3% (95% CI: 2%, 4%) increase in all-cause hospital admissions over the subsequent 8 days. In cause-specific analyses, extreme heat was associated with increased hospitalizations for renal (15%; 95% CI: 9%, 21%) and respiratory (4%; 95% CI: 2%, 7%) diseases, but not for cardiovascular diseases. An added heat-wave effect was observed for renal and respiratory admissions. Conclusion: Extreme heat is associated with increased hospital admissions, particularly for renal causes, among the elderly in the United States. Citation: Gronlund CJ, Zanobetti A, Schwartz JD, Wellenius GA, O’Neill MS. 2014. Heat, heat waves, and hospital admissions among the elderly in the United States, 1992–2006. Environ Health Perspect 122:1187–1192; http://dx.doi.org/10.1289/ehp.120613

ROCs in Eyewitness Identification:Instructions versus Confidence Ratings

From the perspective of signal-detection theory, different lineup instructions may induce different levels of response bias (Clark, 2005). If so, then collecting correct and false identification rates across different instructional conditions will trace out the ROC – the same ROC that, theoretically, could also be traced out from a single instruction condition in which each eyewitness decision is accompanied by a confidence rating. We tested whether the two approaches do in fact yield the same ROC. Participants were assigned to a confidence rating condition or to an instructional biasing condition (liberal, neutral, unbiased, or conservative). After watching a video of a mock crime, participants were presented with instructions followed by a 6-person simultaneous photo lineup. The ROCs from both methods were similar, but they were not exactly the same. These findings have potentially important policy implications for how the legal system should go about controlling eyewitness response bias

Age differences (or lack thereof) in discriminability for lineups and showups

Previous research reveals that showups are an inferior eyewitness identification procedure to lineups, but no single study has compared younger and older adults' identification decisions for both of these procedures. We had witnesses watch a mock crime video and then make an identification decision from a fair lineup, a biased lineup, or a showup that contained the perpetrator or a designated innocent suspect. Receiver operating characteristic (ROC) analysis showed that identification accuracy was higher from a lineup than from a showup for both age groups, even if the lineup was biased. In addition, calibration curves revealed that witnesses were underconfident when choosing from a fair lineup but overconfident when choosing from a showup. These results reinforce prior research asserting the superiority of lineups over showups

A pedagogy of friendship: young children's friendships and how schools can support them?

Children’s friendships are often neglected by teachers and researchers. This phenomenological study conducted with seven children aged five and six years explores young children’s perceptions of their everyday friendship experiences. This multi-method study used role play interviews, drawings and persona doll scenarios to consider children’s everyday experiences of friendship in school. The paper discusses the importance of socio-cultural aspects of children’s friendship including: imaginary friends; losing friends; protecting time and space to develop friendships and children’s routines and practices as they form and maintain friendships. Data and findings are discussed, leading to an original conceptual framework: a ‘Pedagogy of Friendship’. This is designed to help children make meaning from their friendship experiences and also provide practitioners with the opportunity to nurture and scaffold children through their friendship experiences in schools. We suggest that there is a need to raise the profile of children’s friendships in early childhood education and generate an educational perspective on friendship. Finally we conclude that listening to children’s views of friendship indicates that the application of the framework of a ‘Pedagogy of Friendship’ would be beneficial to children’s all round learning and development. Keywords - children's perceptions, phenomenology, friendship, key stage one, Pedagogy of Friendshi

Boundaries of Semantic Distraction: Dominance and Lexicality Act at Retrieval

Three experiments investigated memory for semantic information with the goal of determining boundary conditions for the manifestation of semantic auditory distraction. Irrelevant speech disrupted the free recall of semantic category-exemplars to an equal degree regardless of whether the speech coincided with presentation or test phases of the task (Experiment 1) and occurred regardless of whether it comprised random words or coherent sentences (Experiment 2). The effects of background speech were greater when the irrelevant speech was semantically related to the to-be-remembered material, but only when the irrelevant words were high in output dominance (Experiment 3). The implications of these findings in relation to the processing of task material and the processing of background speech is discussed

Consensus on Upper Gastrointestinal Endoscopy Key Performance Indicators to Reduce Post Endoscopy Upper Gastrointestinal Cancer

Background: Upper gastrointestinal (UGI) endoscopy lacks established key performance indicators. Up to three‐fold variation in post endoscopy upper gastrointestinal cancer rates has been observed among endoscopy providers in England, highlighting the need for standardisation of UGI endoscopy practices. Objective: We aimed to achieve consensus on evidence‐based key performance indicators to reduce post endoscopy upper gastrointestinal cancer. Methods: Modified nominal group technique was employed in two consensus workshops, with representation from clinicians, patients and relatives, moderated by James Lind Alliance facilitators. Potential indicators were identified from the umbrella systematic review, English provider post endoscopy upper gastrointestinal cancer rates, and differences in endoscopy practices from the National Endoscopy Database between providers with the highest (worst) and lowest (best) post endoscopy upper gastrointestinal cancer rates. KPIs were categorised as provider or endoscopist/procedure related and ranked as of major or minor importance. Minimum standards were proposed where possible. Results: Participants included 14 clinicians (gastroenterologists and UGI surgeons), 3 nurse endoscopists, 2 UGI cancer nurse specialists, 14 patients, their relatives and representatives from patient support groups and four observers. Endoscopy provider related major key performance indicators and proposed standards included monitoring post endoscopy upper gastrointestinal cancer rates (minimum standard ≤ 7%); less intense endoscopy lists (maximum 10 ‘points’ per list [one point is equivalent to 15 min]); endoscopy provider accreditation (all providers); and premalignant condition surveillance on dedicated lists by endoscopists with adequate training (> 90% surveillance endoscopies). Endoscopist/procedure related major key performance indicators included: examination time ≥ 7 min; training in early UGI neoplasia recognition (all endoscopists); mucosal view quality recorded and cleansing agents used if not excellent (> 90% endoscopies); intravenous sedation offered to all appropriate patients; recommended number of biopsies from cancer associated or premalignant lesions (> 90% endoscopy where such lesions identified); and endoscopists' annual UGI endoscopy volume > 100 (all endoscopists). Conclusion: This study offers a consensus on the key performance indicators and minimum standards that should be used to improve UGI endoscopy quality and reduce post endoscopy upper gastrointestinal cancer

Strategies to Reduce the Harmful Effects of Extreme Heat Events: A Four-City Study

Extreme heat events (EHEs) are becoming more intense, more frequent and longer lasting in the 21st century. These events can disproportionately impact the health of low-income, minority, and urban populations. To better understand heat-related intervention strategies used by four U.S. cities, we conducted 73 semi-structured interviews with government and non-governmental organization leaders representing public health, general social services, emergency management, meteorology, and the environmental planning sectors in Detroit, MI; New York City, NY; Philadelphia, PA and Phoenix, AZ—cities selected for their diverse demographics, climates, and climate adaptation strategies. We identified activities these leaders used to reduce the harmful effects of heat for residents in their city, as well as the obstacles they faced and the approaches they used to evaluate these efforts. Local leaders provided a description of how local context (e.g., climate, governance and city structure) impacted heat preparedness. Despite the differences among study cities, political will and resource access were critical to driving heat-health related programming. Upon completion of our interviews, we convened leaders in each city to discuss these findings and their ongoing efforts through day-long workshops. Our findings and the recommendations that emerged from these workshops could inform other local or national efforts towards preventing heat-related morbidity and mortality