Random planar graphs and the London street network

In this paper we analyse the street network of London both in its primary and dual representation. To understand its properties, we consider three idealised models based on a grid, a static random planar graph and a growing random planar graph. Comparing the models and the street network, we find that the streets of London form a self-organising system whose growth is characterised by a strict interaction between the metrical and informational space. In particular, a principle of least effort appears to create a balance between the physical and the mental effort required to navigate the city

Compatibility of pentoxifylline and parenteral medications

Objective: To investigate the physical and chemical compatibility of pentoxifylline (PTX) with a range of parenteral medications used in neonatal intensive care. Design: PTX and drug solutions were combined in glass vials, inspected for physical incompatibility and evaluated on the basis of PTX concentrations for chemical compatibility. Results: No precipitation, colour change or turbidity was observed in any of the test mixtures. The PTX concentration was approximately 5.5% lower when combined with undiluted calcium gluconate injection (100 mg/mL). The PTX concentration ratios for all other combinations, including diluted calcium gluconate injection (50 mg/mL), were in the range of 99.5%-102%. Conclusion: In simulated Y-site conditions, PTX was found to be compatible with 15 parenteral medications and six total parenteral nutrition solutions. Based on PTX concentration tests, it would be prudent to avoid mixing PTX with undiluted calcium gluconate injection

MetroNet: A Metropolitan Simulation Model Based on Commuting Processes

Part 3: Short PapersInternational audienceThe aim of this work is to identify a set of fundamental rules that govern the interactions within urban systems at the metropolitan scale. For that, we developed an USM (Urban Simulation Model) specifically designed to study the evolution and dynamics of systems of cities. Our model is innovative in its structure: it is a superposition of cellular automata and agent based modeling approaches (that are essentially spatial analyses) and a complex network approach (that is essentially a topological analysis). This implies that in our model, the local activities and interaction of agents give rise to the global urban structure and network that in turn affects the agents’ cognition, behavior, movement and action in the city and so on in circular causality. The model simulates commuting patterns of agents within a metropolis. The agents in our model represent workers who look for working places, the nodes represent urban employment centers, and the links represent commuters. Our results address three issues: the first suggests that the perception of urban boundaries plays a significant role in the metropolitan evolution in terms of network topology. This means that the existence of business centers, located in proximity to each other (but belonging to different municipalities) may lead to the emergence of new centers at the metropolis scale. The second issue concerns urban segregation; our results suggest that the location preferences of the agents regarding proximity to similar/different agents have a major affect not only on the urban morphology but also on the topology of the urban network. The third and last issue concerns the size distributions of agents in our model; these distributions correspond to all types of homogenous distributions observed in real system of cities

Long-read whole genome sequencing and comparative analysis of six strains of the human pathogen Orientia tsutsugamushi

10.1371/journal.pntd.0006566PLoS Neglected Tropical Diseases126e000656