The Incremental Cooperative Design of Preventive Healthcare Networks

This document is the Accepted Manuscript version of the following article: Soheil Davari, 'The incremental cooperative design of preventive healthcare networks', Annals of Operations Research, first published online 27 June 2017. Under embargo. Embargo end date: 27 June 2018. The final publication is available at Springer via http://dx.doi.org/10.1007/s10479-017-2569-1.In the Preventive Healthcare Network Design Problem (PHNDP), one seeks to locate facilities in a way that the uptake of services is maximised given certain constraints such as congestion considerations. We introduce the incremental and cooperative version of the problem, IC-PHNDP for short, in which facilities are added incrementally to the network (one at a time), contributing to the service levels. We first develop a general non-linear model of this problem and then present a method to make it linear. As the problem is of a combinatorial nature, an efficient Variable Neighbourhood Search (VNS) algorithm is proposed to solve it. In order to gain insight into the problem, the computational studies were performed with randomly generated instances of different settings. Results clearly show that VNS performs well in solving IC-PHNDP with errors not more than 1.54%.Peer reviewe

Dust environment and dynamical history of a sample of short-period comets: II. 81P/Wild 2 and 103P/Hartley 2

Aims. This paper is a continuation of the first paper in this series, where we presented an extended study of the dust environment of a sample of short-period comets and their dynamical history. On this occasion, we focus on comets 81P/Wild 2 and 103P/Hartley 2, which are of special interest as targets of the spacecraft missions Stardust and EPOXI. Methods. As in the previous study, we used two sets of observational data: a set of images, acquired at Sierra Nevada and Lulin observatories, and the Afρ data as a function of the heliocentric distance provided by the amateur astronomical association Cometas-Obs. The dust environment of comets (dust loss rate, ejection velocities, and size distribution of the particles) was derived from our Monte Carlo dust tail code. To determine their dynamical history we used the numerical integrator Mercury 6.2 to ascertain the time spent by these objects in the Jupiter family Comet region. Results. From the dust analysis, we conclude that both 81P/Wild 2 and 103P/Hartley 2 are dusty comets, with an annual dust production rate of 2.8 × 109 kg yr-1 and (0.4-1.5) × 109 kg yr-1, respectively. From the dynamical analysis, we determined their time spent in the Jupiter family Comet region as ~40 yr in the case of 81P/Wild 2 and ~1000 yr for comet 103P/Hartley 2. These results imply that 81P/Wild 2 is the youngest and the most active comet of the eleven short-period comets studied so far, which tends to favor the correlation between the time spent in JFCs region and the comet activity previously discussed

25th annual computational neuroscience meeting: CNS-2016

The same neuron may play different functional roles in the neural circuits to which it belongs. For example, neurons in the Tritonia pedal ganglia may participate in variable phases of the swim motor rhythms [1]. While such neuronal functional variability is likely to play a major role the delivery of the functionality of neural systems, it is difficult to study it in most nervous systems. We work on the pyloric rhythm network of the crustacean stomatogastric ganglion (STG) [2]. Typically network models of the STG treat neurons of the same functional type as a single model neuron (e.g. PD neurons), assuming the same conductance parameters for these neurons and implying their synchronous firing [3, 4]. However, simultaneous recording of PD neurons shows differences between the timings of spikes of these neurons. This may indicate functional variability of these neurons. Here we modelled separately the two PD neurons of the STG in a multi-neuron model of the pyloric network. Our neuron models comply with known correlations between conductance parameters of ionic currents. Our results reproduce the experimental finding of increasing spike time distance between spikes originating from the two model PD neurons during their synchronised burst phase. The PD neuron with the larger calcium conductance generates its spikes before the other PD neuron. Larger potassium conductance values in the follower neuron imply longer delays between spikes, see Fig. 17.Neuromodulators change the conductance parameters of neurons and maintain the ratios of these parameters [5]. Our results show that such changes may shift the individual contribution of two PD neurons to the PD-phase of the pyloric rhythm altering their functionality within this rhythm. Our work paves the way towards an accessible experimental and computational framework for the analysis of the mechanisms and impact of functional variability of neurons within the neural circuits to which they belong

Dry season rainfall as a source of transpired water in a seasonal, evergreen forest in the western Amazon region inferred by water stable isotopes

The present work aimed to investigate the potential sources of water for plants in an area of evergreen forest located in western Amazonia (Rebio Jaru). We used natural abundance of water isotopes - δ2H and δ18O - to trace the main source of water to plants in the beginning of the dry period (May 2016) and in the end of the dry period/transition to the wet period (October 2016) following a severe El Niño drought (ENSO 2015/16). Soil samples were collected in a soil profile up to 4 m depth. Plant samples from 18 trees (14 species) were collected in May and in October 2016. Rainwater and river water samples were collected between September 2015 and February 2017. We found that, at the end of the dry period/transition to the wet period (i.e., October 2016), the average plant xylem signal was more enriched (δ2H: -20.0 ± 8.1 ‰; δ18O: -1.13 ± 1.88 ‰) than in May 2016 (δ2H: -36.7 ± 5.6 ‰; δ18O: -3.50 ± 1.30 ‰), the onset of the dry period. The averaged isotopic soil signal in May 2016 (δ2H: -35.4 ± 5.90 ‰; δ18O: -5.19 ± 0.70 ‰) is slightly more depleted than in October (δ2H: -27.6 ± 13.8 ‰; δ18O: -4.35 ± 1.73 ‰) and, in general, more depleted than the xylem signal. In the dual isotope space, the xylem signal at the beginning of the dry period follows the rainfall signal of the wet period, while the xylem signal at the end of the dry period/transition to wet period follows the signal of the dry season rainfall, suggesting plants mostly transpires a most recent rainwater. Contrary to what was expected, we did not find evidence in the xylem signal of the water stored in the soil pores, which suggests that, to attend the water demands of the dry period, plants do not use the water from past periods stored in the soil layers

Modelling the action potential propagation in a heart with structural heterogeneities: From high‐resolution MRI to numerical simulations

International audienceMathematical modelling and numerical simulation in cardiac electrophysiology have already been studied extensively. However, there is a clear lack of techniques and methodologies for studying the propagation of action potential in a heart with structural defects. In this article, we present a modified version of the bidomain model, derived using homogenisation techniques with the assumption of existence of diffusive inclusions in the cardiac tissue. The diffusive inclusions represent regions without electrically active myocytes, for example, fat, fibrosis, and so forth. We present an application of this model to a rat heart. Starting from high-resolution MRI, the geometry of the heart is built and meshed using image processing techniques. We perform a study of the effects of tissue heterogeneities induced by diffusive inclusions on the velocity and shape of the depolarisation wavefront. We present several test cases with different geometries of diffusive inclusions. We reach the conclusion that the conduction velocity is not affected in the best cases, while it is affected by up to 76% in the worst case scenario. Additionally, the shape of the wavefront was affected in some cases

Nitrogen donor ligands and their coordination compounds as a tool for treatment of multi drug resistant tumors

In our previous work we prepared several libraries of compounds: organic ligands with N-donor atoms (in some cases with additional chalcogen donor atoms) and corresponding metal complexes. These compounds have been tested against various cancer and cancer stem cells (CSCs) and the most potent compounds have been identified. For selected compounds a detailed mechanistic study regarding antitumor activity has been performed together with in silico and experimental molecular target(s) identification. The most promising results will be presented. A novel line of our research represents building of drug delivery systems based on coordination polymers (CPs). CPs represent assembly of different building blocks - metals and organic linkers, with different porosities and dimensionalities (from 1D to 3D). CPs have demonstrated inimitable advantages in drug delivery systems. These advantages are nontoxicity, well-controlled drug release and stability, which can be the most pivotal characteristics of every efficient carrier. The mentioned properties make CPs one of the most applicable carriers in anticancer drug delivery systems. A novel class of Ag-based 1D-3D CPs with organic thiocyanates and substituted thiomorpholine ligands has been developed in collaboration of several groups. Studies of their drug delivery properties are in progress