Coherent Moving States in Highway Traffic (Originally: Moving Like a Solid Block)

Recent advances in multiagent simulations have made possible the study of realistic traffic patterns and allow to test theories based on driver behaviour. Such simulations also display various empirical features of traffic flows, and are used to design traffic controls that maximise the throughput of vehicles in heavily transited highways. In addition to its intrinsic economic value, vehicular traffic is of interest because it may throw light on some social phenomena where diverse individuals competitively try to maximise their own utilities under certain constraints. In this paper, we present simulation results that point to the existence of cooperative, coherent states arising from competitive interactions that lead to a new phenomenon in heterogeneous highway traffic. As the density of vehicles increases, their interactions cause a transition into a highly correlated state in which all vehicles practically move with the same speed, analogous to the motion of a solid block. This state is associated with a reduced lane changing rate and a safe, high and stable flow. It disappears as the vehicle density exceeds a critical value. The effect is observed in recent evaluations of Dutch traffic data.Comment: Submitted on April 21, 1998. For related work see http://www.theo2.physik.uni-stuttgart.de/helbing.html and http://www.parc.xerox.com/dynamics

Preoperative computed tomography staging of nonmetastatic colon cancer predicts outcome: implications for clinical trials

Colon cancer patients routinely undergo preoperative computed tomography (CT) scanning, but local staging is thought to be inaccurate. We aimed to determine if clinical outcome could be predicted from radiological features of the primary tumour. Consecutive patients at one hospital undergoing primary resection for colon cancer during 2000–2004 were included. Patients with visible metastases were excluded. Preoperative CT scans were reviewed independently by two radiologists blinded to histological stage and outcome. Images of the primary tumour were evaluated according to conventional TNM criteria and patients were stratified into ‘good' or ‘poor' prognosis groups. Comparison was made between prognostic group and actual clinical outcome. Hundred and twenty-six preoperative CT scans were reviewed. T-stage and nodal status was correctly predicted in only 60 and 62%, respectively. However, inter-observer agreement for prognostic group was 79% (κ=0.59) and 3-year relapse-free survival was 71 and 43% for the CT-predicted ‘good' and ‘poor' groups, respectively (P<0.0066). This compared favourably with 75 vs 43% for histology-predicted prognostic groups. Computed tomography is a robust method for stratifying patients preoperatively, with similar accuracy to histopathology for predicting outcome. Recognition of poor prognosis tumours preoperatively may permit investigation into the future use of neo-adjuvant therapy in colon cancer

Complex Dynamics of Bus, Tram and Elevator Delays in Transportation System

It is necessary and important to operate buses and trams on time. The bus schedule is closely related to the dynamic motion of buses. In this part, we introduce the nonlinear maps for describing the dynamics of shuttle buses in the transportation system. The complex motion of the buses is explained by the nonlinear-map models. The transportation system of shuttle buses without passing is similar to that of the trams. The transport of elevators is also similar to that of shuttle buses with freely passing. The complex dynamics of a single bus is described in terms of the piecewise map, the delayed map, the extended circle map and the combined map. The dynamics of a few buses is described by the model of freely passing buses, the model of no passing buses, and the model of increase or decrease of buses. The nonlinear-map models are useful to make an accurate estimate of the arrival time in the bus transportation

Individual and setting level predictors of the implementation of a skin cancer prevention program: a multilevel analysis

<p>Abstract</p> <p>Background</p> <p>To achieve widespread cancer control, a better understanding is needed of the factors that contribute to successful implementation of effective skin cancer prevention interventions. This study assessed the relative contributions of individual- and setting-level characteristics to implementation of a widely disseminated skin cancer prevention program.</p> <p>Methods</p> <p>A multilevel analysis was conducted using data from the Pool Cool Diffusion Trial from 2004 and replicated with data from 2005. Implementation of Pool Cool by lifeguards was measured using a composite score (implementation variable, range 0 to 10) that assessed whether the lifeguard performed different components of the intervention. Predictors included lifeguard background characteristics, lifeguard sun protection-related attitudes and behaviors, pool characteristics, and enhanced (<it>i.e</it>., more technical assistance, tailored materials, and incentives are provided) versus basic treatment group.</p> <p>Results</p> <p>The mean value of the implementation variable was 4 in both years (2004 and 2005; SD = 2 in 2004 and SD = 3 in 2005) indicating a moderate implementation for most lifeguards. Several individual-level (lifeguard characteristics) and setting-level (pool characteristics and treatment group) factors were found to be significantly associated with implementation of Pool Cool by lifeguards. All three lifeguard-level domains (lifeguard background characteristics, lifeguard sun protection-related attitudes and behaviors) and six pool-level predictors (number of weekly pool visitors, intervention intensity, geographic latitude, pool location, sun safety and/or skin cancer prevention programs, and sun safety programs and policies) were included in the final model. The most important predictors of implementation were the number of weekly pool visitors (inverse association) and enhanced treatment group (positive association). That is, pools with fewer weekly visitors and pools in the enhanced treatment group had significantly higher program implementation in both 2004 and 2005.</p> <p>Conclusions</p> <p>More intense, theory-driven dissemination strategies led to higher levels of implementation of this effective skin cancer prevention program. Issues to be considered by practitioners seeking to implement evidence-based programs in community settings, include taking into account both individual-level and setting-level factors, using active implementation approaches, and assessing local needs to adapt intervention materials.</p

The impact of disseminating the whole-community project '10,000 Steps': a RE-AIM analysis

<p>Abstract</p> <p>Background</p> <p>There are insufficient research reports on the wide-scale dissemination of effective whole-community physical activity (PA) programs. The purpose of this paper is to evaluate the impact of the wide-scale dissemination of '10,000 Steps', using the RE-AIM framework.</p> <p>Methods</p> <p>Dissemination efforts targeted a large region of Belgium and were concentrated on media strategies and peer networks of specific professional organizations, such as local health promotion services. Heads of department of 69 organizations received an on-line survey to assess project awareness, adoption, implementation and intended continuation of '10,000 Steps'. On the individual level, 755 citizens living in the work area of the organizations were interviewed for project awareness and PA levels. Measures were structured according to the RE-AIM dimensions (reach, effectiveness, adoption, implementation, maintenance). Independent sample <it>t </it>and chi-square tests were used to compare groups for representativeness at the organizational and individual level, and for individual PA differences.</p> <p>Results</p> <p>Of all organizations, 90% was aware of '10,000 Steps' (effectiveness - organizational level) and 36% adopted the project (adoption). The global implementation score was 52%. One third intended to continue the project in the future (maintenance) and 48% was still undecided. On the individual level, 35% of citizens were aware of '10,000 Steps' (reach). They reported significantly higher leisure-time PA levels than those not aware of '10,000 Steps' (256 ± 237 and 207 ± 216 min/week, respectively; <it>t </it>= -2.8; p < .005) (effectiveness - individual level). When considering representativeness, adoption of '10.000 Steps' was independent of most organizational characteristics, except for years of experience in PA promotion (7.6 ± 4.6 and 2.9 ± 5.9 years for project staff and non-project staff members, respectively; <it>t </it>= 2.79; <it>p </it>< 0.01). Project awareness in citizens was independent of all demographic characteristics.</p> <p>Conclusions</p> <p>'10,000 Steps' shows potential for wide-scale dissemination but a supportive linkage system seems recommended to encourage adoption levels and high quality implementation.</p

Developing cancer warning statements for alcoholic beverages

Background: There is growing evidence of the increased cancer risk associated with alcohol consumption, but this is not well understood by the general public. This study investigated the acceptability among drinkers of cancer warning statements for alcoholic beverages. Methods: Six focus groups were conducted with Australian drinkers to develop a series of cancer-related warning statements for alcohol products. Eleven cancer warning statements and one general health warning statement were subsequently tested on 2,168 drinkers via an online survey. The statements varied by message frame (positive vs negative), cancer reference (general vs specific), and the way causality was communicated (‘increases risk of cancer’ vs ‘can cause cancer’). Results: Overall, responses to the cancer statements were neutral to favorable, indicating that they are unlikely to encounter high levels of negative reaction from the community if introduced on alcoholic beverages. Females, younger respondents, and those with higher levels of education generally found the statements to be more believable, convincing, and personally relevant. Positively framed messages, those referring to specific forms of cancer, and those using ‘increases risk of cancer’ performed better than negatively framed messages, those referring to cancer in general, and those using the term ‘can cause cancer’. Conclusion: Cancer warning statements on alcoholic beverages constitute a potential means of increasing awareness about the relationship between alcohol consumption and cancer risk

A high fat diet increases mitochondrial fatty acid oxidation and uncoupling to decrease efficiency in rat heart

Elevated levels of cardiac mitochondrial uncoupling protein 3 (UCP3) and decreased cardiac efficiency (hydraulic power/oxygen consumption) with abnormal cardiac function occur in obese, diabetic mice. To determine whether cardiac mitochondrial uncoupling occurs in non-genetic obesity, we fed rats a high fat diet (55% kcal from fat) or standard laboratory chow (7% kcal from fat) for 3 weeks, after which we measured cardiac function in vivo using cine MRI, efficiency in isolated working hearts and respiration rates and ADP/O ratios in isolated interfibrillar mitochondria; also, measured were medium chain acyl-CoA dehydrogenase (MCAD) and citrate synthase activities plus uncoupling protein 3 (UCP3), mitochondrial thioesterase 1 (MTE-1), adenine nucleotide translocase (ANT) and ATP synthase protein levels. We found that in vivo cardiac function was the same for all rats, yet oxygen consumption was 19% higher in high fat-fed rat hearts, therefore, efficiency was 21% lower than in controls. We found that mitochondrial fatty acid oxidation rates were 25% higher, and MCAD activity was 23% higher, in hearts from rats fed the high fat diet when compared with controls. Mitochondria from high fat-fed rat hearts had lower ADP/O ratios than controls, indicating increased respiratory uncoupling, which was ameliorated by GDP, a UCP3 inhibitor. Mitochondrial UCP3 and MTE-1 levels were both increased by 20% in high fat-fed rat hearts when compared with controls, with no significant change in ATP synthase or ANT levels, or citrate synthase activity. We conclude that increased cardiac oxygen utilisation, and thereby decreased cardiac efficiency, occurs in non-genetic obesity, which is associated with increased mitochondrial uncoupling due to elevated UCP3 and MTE-1 levels