Cellular Models for River Networks

A cellular model introduced for the evolution of the fluvial landscape is revisited using extensive numerical and scaling analyses. The basic network shapes and their recurrence especially in the aggregation structure are then addressed. The roles of boundary and initial conditions are carefully analyzed as well as the key effect of quenched disorder embedded in random pinning of the landscape surface. It is found that the above features strongly affect the scaling behavior of key morphological quantities. In particular, we conclude that randomly pinned regions (whose structural disorder bears much physical meaning mimicking uneven landscape-forming rainfall events, geological diversity or heterogeneity in surficial properties like vegetation, soil cover or type) play a key role for the robust emergence of aggregation patterns bearing much resemblance to real river networks.Comment: 7 pages, revtex style, 14 figure

High contrast microstructural visualisation of natural acellular matrices by means of phase-based x-ray tomography

Acellular scaffolds obtained via decellularization are a key instrument in regenerative medicine both per se and to drive the development of future-generation synthetic scaffolds that could become available off-the-shelf. In this framework, imaging is key to the understanding of the scaffolds’ internal structure as well as their interaction with ells and other organs, including ideally post-implantation. Scaffolds of a wide range of intricate organs (oesophagus, lung, liver and small intestine) were imaged with x-ray phase contrast computed tomography (PC-CT). Image quality was sufficiently high to visualize scaffold micro architecture and to detect major anatomical features, such as the oesophageal mucosal-submucosal separation, pulmonary alveoli and intestinal villi. These results are a long-sought step for the field of regenerative medicine: until now, histology and scanning electron microscopy have been the gold standard to study the scaffold structure. However, they are both destructive: hence, they are not suitable for imaging scaffolds prior to transplantation, and have no prospect for post-transplantation use. PC-CT, on the other hand, is non-destructive, 3D and fully quantitative. Importantly, not only do we demonstrate achievement of high image quality at two different synchrotron facilities, but also with commercially available x-ray equipment, which makes the method instantly available worldwide to any research laboratory

Determinants of out-of-hours service users' potentially inappropriate referral or non-referral to an emergency department: a retrospective cohort study in a local health authority, Veneto Region, Italy

BACKGROUND: A growing presence of inappropriate patients has been recognised as one of the main factors influencing emergency department (ED) overcrowding, which is a very widespread problem all over the world. On the other hand, out-of-hours (OOH) physicians must avoid delaying the diagnostic and therapeutic course of patients with urgent medical conditions. The aim of this study was to analyse the appropriateness of patient management by OOH services, in terms of their potentially inappropriate referral or non-referral of non-emergency cases to the ED. METHODS: This was an observational retrospective cohort study based on data collected in 2011 by the local health authority No. 4 in the Veneto Region (Italy). After distinguishing between patients contacting the OOH service who were or were not referred to the ED, and checking for patients actually presenting to the ED within 24\u2005hours thereafter, these patients' medical management was judged as potentially appropriate or inappropriate. RESULTS: The analysis considered 22\u2005662 OOH service contacts recorded in 2011. The cases of potentially inappropriate non-referral to the ED were 392 (1.7% of all contacts), as opposed to 1207 potentially inappropriate referrals (5.3% of all contacts). Age, nationality, type of disease and type of intervention by the OOH service were the main variables associated with the appropriateness of patient management. CONCLUSIONS: These findings may be useful for pinpointing the factors associated with a potentially inappropriate patient management by OOH services and thus contribute to improving the deployment of healthcare and the quality of care delivered by OOH services

Linking Community Participatory Research to Global Policymaking: Lessons Learned

The past two decades saw a proliferation of opportunities for the perspectives of people experiencing poverty and marginalisation to input into global policymaking spaces. So far these efforts have been contested, with attempts to embed participatory methodologies facilitating only limited consultation and falling into many pitfalls. While Participate was built on learning from previous attempts to influence global policy, we aimed to further understand participatory processes, and advance practical mechanisms for participation at every level of decision-making, from local to national and global. Participate emphasises the interactions between these levels and the importance of impacting multiple levels in order to create lasting, transformative change. This chapter describes what has been learnt about bringing the voices on the ground into global policymaking. We examine how and by whom the knowledge and evidence created were used, and the barriers and challenges to embedding this knowledge into global policy processes, through the following questions: • What have been the challenges to embedding participatory processes into global policy spaces? • What have these pathways of influence looked like, and what are some of the key lessons learned from these

Disorder-induced critical behavior in driven diffusive systems

Using dynamic renormalization group we study the transport in driven diffusive systems in the presence of quenched random drift velocity with long-range correlations along the transport direction. In dimensions $d\mathopen< 4$ we find fixed points representing novel universality classes of disorder-dominated self-organized criticality, and a continuous phase transition at a critical variance of disorder. Numerical values of the scaling exponents characterizing the distributions of relaxation clusters are in good agreement with the exponents measured in natural river networks