Community detection and role identification in directed networks: understanding the Twitter network of the care.data debate

With the rise of social media as an important channel for the debate and discussion of public affairs, online social networks such as Twitter have become important platforms for public information and engagement by policy makers. To communicate effectively through Twitter, policy makers need to understand how influence and interest propagate within its network of users. In this chapter we use graph-theoretic methods to analyse the Twitter debate surrounding NHS Englands controversial care.data scheme. Directionality is a crucial feature of the Twitter social graph - information flows from the followed to the followers - but is often ignored in social network analyses; our methods are based on the behaviour of dynamic processes on the network and can be applied naturally to directed networks. We uncover robust communities of users and show that these communities reflect how information flows through the Twitter network. We are also able to classify users by their differing roles in directing the flow of information through the network. Our methods and results will be useful to policy makers who would like to use Twitter effectively as a communication medium

Spiking Neural P Systems with Structural Plasticity: Attacking the Subset Sum Problem

Spiking neural P systems with structural plasticity (in short, SNPSP systems) are models of computations inspired by the function and structure of biological neurons. In SNPSP systems, neurons can create or delete synapses using plasticity rules. We report two families of solutions: a non-uniform and a uniform one, to the NP-complete problem Subset Sum using SNPSP systems. Instead of the usual rule-level nondeterminism (choosing which rule to apply) we use synapse-level nondeterminism (choosing which synapses to create or delete). The nondeterminism due to plasticity rules have the following improvements from a previous solution: in our non-uniform solution, plasticity rules allowed for a normal form to be used (i.e. without forgetting rules or rules with delays, system is simple, only synapse-level nondeterminism); in our uniform solution the number of neurons and the computation steps are reduced.Ministerio de Economía y Competitividad TIN2012-3743

Almost reducibility for finitely differentiable SL(2,R)-valued quasi-periodic cocycles

Quasi-periodic cocycles with a diophantine frequency and with values in SL(2,R) are shown to be almost reducible as long as they are close enough to a constant, in the topology of k times differentiable functions, with k great enough. Almost reducibility is obtained by analytic approximation after a loss of differentiability which only depends on the frequency and on the constant part. As in the analytic case, if their fibered rotation number is diophantine or rational with respect to the frequency, such cocycles are in fact reducible. This extends Eliasson's theorem on Schr\"odinger cocycles to the differentiable case

Probabilistic Guarded P Systems, A New Formal Modelling Framework

Multienvironment P systems constitute a general, formal framework for modelling the dynamics of population biology, which consists of two main approaches: stochastic and probabilistic. The framework has been successfully used to model biologic systems at both micro (e.g. bacteria colony) and macro (e.g. real ecosystems) levels, respectively. In this paper, we extend the general framework in order to include a new case study related to P. Oleracea species. The extension is made by a new variant within the probabilistic approach, called Probabilistic Guarded P systems (in short, PGP systems). We provide a formal definition, a simulation algorithm to capture the dynamics, and a survey of the associated software.Ministerio de Economía y Competitividad TIN2012- 37434Junta de Andalucía P08-TIC-0420

Spectroscopic ellipsometry study of barrier width effect in self-organized InGaAs/GaAs QDs laser diodes

Molecular beam epitaxy (MBE) is used to grow InGaAs/GaAs quantum dots (QDs) laser diodes (LDs) with different barrier widths (5, 10 and 15 nm) at 580 ºC on GaAs substrates. Optical properties of the InGaAs/GaAs QDs LDs have been investigated by using the spectroscopic ellipsometry (SE) technique. A general oscillator optical model has been utilized to fit the experimental data in order to obtain the LD layer thicknesses, refractive index and absorption coefficient. The dielectric function, the energy band gap and the surface and volume energy loss functions are computed in the energy range 1-6 eV. The optical properties of the deposited InGaAs/GaAs QDs LDs are found to be affected by the barrier width, which give more insight into carriers dynamics and optical parameters in these devices. The refractive indices, the extinction coefficients and the dielectric constants of the LDs with barrier widths 15 and 10 nm are relatively larger than those of the LD with barrier width 5 nm. These indicate that optical properties of LDs with larger barrier widths (15 and 10 nm) will be improved. The interband transition energies in the three devices have calculated and identified. Two energy gaps at 1.04 and ~1.37 eV are obtained for all the heterostructures which indicates that fabricated LDs may be operating for a wavelength of 1.23 m at room temperature

Neuroimmunology - the past, present and future

Neuroimmunology as a separate discipline has its roots in the fields of neurology, neuroscience and immunology. Early studies of the brain by Golgi and Cajal, the detailed clinical and neuropathology studies of Charcot and Thompson’s seminal paper on graft acceptance in the central nervous system, kindled a now rapidly expanding research area, with the aim of understanding pathological mechanisms of inflammatory components of neurological disorders. While neuroimmunologists originally focused on classical neuroinflammatory disorders, such as multiple sclerosis and infections, there is strong evidence to suggest that the immune response contributes to genetic white matter disorders, epilepsy, neurodegenerative diseases, neuropsychiatric disorders, peripheral nervous system and neuro‐oncological conditions, as well as ageing. Technological advances have greatly aided our knowledge of how the immune system influences the nervous system during development and ageing, and how such responses contribute to disease as well as regeneration and repair. Here, we highlight historical aspects and milestones in the field of neuroimmunology and discuss the paradigm shifts that have helped provide novel insights into disease mechanisms. We propose future perspectives including molecular biological studies and experimental models that may have the potential to push many areas of neuroimmunology. Such an understanding of neuroimmunology will open up new avenues for therapeutic approaches to manipulate neuroinflammation

L'inhibition de l'entartrage par les eaux géothermales du sud tunisien. Étude sur site

Une nappe d'eaux fossiles à grande profondeur (800 à 2 700 mètres) a été mise en exploitation dans le Sud-Tunisien pour alimenter une usine d'osmose inverse située à Gabès ayant une production de 15 000 m3 /jour, afin de lutter contre la désertification par irrigation et d'assurer le chauffage de serres pour la production de primeurs. La grande dureté (TH de l'ordre de 100 à 140 °F) de ces eaux géothermales a pour conséquence le colmatage rapide des conduites de distribution : 40 à 50 tonnes de tartre par forage, constitué essentiellement de carbonate de calcium, précipitent chaque année. Ce tartre est constitué d'aragonite comme le montrent la microscopie électronique à balayage et la diffraction des rayons X. Une technique électrochimique, la chronoélectrogravimétrie, permet d'étudier l'inhibition de l'entartrage par des composés de la famille des phosphates inorganiques, des phosphonates organiques et des polycarboxylates. La concentration efficace de chacun de ces inhibiteurs agissant par effet de seuil a été déterminée : elle est de l'ordre de 1,1 à 1,5 mg.l-1 pour l'eau du forage de EL HAMMA. Un essai sur le site de EL MANSOURA a été effectué en privilégiant un inhibiteur produit industriellement dans le Sud-Tunisien, le triphosphate de sodium. A la concentration de 1 mg.l-1 il évite l'entartrage du système de refroidissement de type cascade - piscines et des conduites de distribution.Deep fossil waters are used in Southern Tunisia (Gabès, Kébili, Tozeur) for the Gabès reverse osmosis plant, which delivers a flow rate of 15 000 m3 /day for irrigation and for heating greenhouses used for the production of early fruits and vegetables. Drilling depths vary between 800 and 2 700 meters. Water emerges under a pressure of ca. 20 bars and has a temperature between 50 and 73 °C. Mean flow rate is 7 800 m3 /day.Intake water at the Gabès plant has a salinity of 3.3 g.l-1 ; after reverse osmosis the salinity is less than 0.1 g.l-1. Water used for irrigation has to be cooled. Geothermal waters are characterized by high concentrations of calcium, magnesium, sulphate and chloride. Bicarbonate anions are present at limited concentrations (approx. 2.10-3 mol.l-1) that are, however, sufficient for the formation of large quantities of scale - 40 to 50 tons per year for each drilling. At the outlet of the drill hole, pressure decreases strongly, liberating carbon dioxide to the atmosphere. Water pH increases and the following equilibrium is displaced to the right, with scale precipitation : Ca2+ + 2HCO3-CO2 (g) + CaCO3(s) + H2OScale precipitation has two consequences :- the plugging of distribution pipes: a 85% reduction of the pipe has been observed, after four years, for an initial diameter of 15 cm; - water cooling installations such as cooling towers or pool systems are blocked by large quantities of scale, which have to be removed regularly. Scales have been analysed through inductively coupled plasma spectroscopy and thermogravimetry: calcium carbonate may represent, depending on the origin of the drilling water, 60 to 95% by weight of the solid. Iron oxides, silica, calcium phosphate and aluminum are present. Scanning electron microscopy and X-ray diffraction show that calcium carbonate precipitates in the form of aragonite. This is due to two reasons: the temperature at the drilling outlet is greater than 60 °C and the high magnesium concentration favours aragonite formation. Scale inhibition is possible through the use of certain chemicals such as phosphates, organic phosphonates and polycarboxylates.Chronoelectrogravimetry was used as the experimental method to determine the inhibitor concentration able to suppress scale precipitation. Dissolved oxygen is electrochemically reduced on a gold electrode; hydroxide anions are produced in the vicinity of the electrode and calcium carbonate precipitates according to:4Ca2+ + 4HCO3- + O2 + 4e -> 4CaCO3(s) + 2H2OThe gold electrode is deposited on the quartz disk of a recording microbalance. The electrode is polarized at - 1 V/SCE with a three-electrode potentiostatic device and the weight of CaCO3 deposited is recorded versus time.Four inhibitors have been studied :- PERMATREAT 191, which is the sodium salt of aminotris(methylenephosphonic) acid N(CH2COONa)3; - a proprietary organic phosphonate with high resistance to chlorine oxidation (DEQUEST 6004) ; - phosphonobutanetricarboxylic acid (DEQUEST 7000, BAYHIBIT-AM) ; - a copolymer of acrylic acid and acrylamidopropanesulfonic acid (FERROPHOS 5248). Breakthrough effects are obtained in the case of EL HAMMA water for the following concentrations: PERMATREAT 191: 1.1 mg.l-1 ; DEQUEST 6004: 1.5 mg.l-1 ; DEQUEST 7000: 1.3 mg.l-1 ; FERROPHOS 5248: 1.4 mg.l-1. These concentrations are low and, as a consequence, these inhibitors can be used for antiscale action even with high water flow rates.A field experiment was carried out on the EL MANSOURA drilling where water is cooled in three pools (input water: 5 184 m3 /day, temperature: 60 °C). For economical reasons the chosen inhibitor was sodium triphosphate Na5 P3 O10, which is produced industrially in Southern Tunisia. By chronoelectrogravimetry it has been shown that, with EL MANSOURA water, a breakthrough effect is obtained with a sodium triphosphate concentration of 0.75 mg.l-1.A dosing pump was used to inject sodium triphosphate in such a way that the inhibitor concentration would be 1 mg.l-1 in one of three pools, the two others not being treated. After four months a scale deposit of 23 cm was obtained in the untreated pools and the pipe diameter was reduced by 39%. In the treated pool scale deposit was not observed and the pipe diameter remained unchanged. In the untreated basins, examination of scale with electron scanning microscopy revealed that it was aragonite; in the treated basin, the precipitate was amorphous and an X-ray diffraction pattern with no characteristic bands was obtained.Some algal development was observed in the pool due to phosphate addition but this development was not a nuisance after the four month period. However, it could be suppressed by the use of an organic phosphonate or polycarboxylate as scale inhibitor

Application of Bioactive Thermal Proteome Profiling to Decipher the Mechanism of Action of the Lipid Lowering 132-Hydroxy-pheophytin Isolated from a Marine Cyanobacteria

The acceleration of the process of understanding the pharmacological application of new marine bioactive compounds requires identifying the compound protein targets leading the molecular mechanisms in a living cell. The thermal proteome profiling (TPP) methodology does not fulfill the requirements for its application to any bioactive compound lacking chemical and functional characterization. Here, we present a modified method that we called bTPP for bioactive thermal proteome profiling that guarantees target specificity from a soluble subproteome. We showed that the precipitation of the microsomal fraction before the thermal shift assay is crucial to accurately calculate the melting points of the protein targets. As a probe of concept, the protein targets of 132-hydroxy-pheophytin, a compound previously isolated from a marine cyanobacteria for its lipid reducing activity, were analyzed on the hepatic cell line HepG2. Our improved method identified 9 protein targets out of 2500 proteins, including 3 targets (isocitrate dehydrogenase, aldehyde dehydrogenase, phosphoserine aminotransferase) that could be related to obesity and diabetes, as they are involved in the regulation of insulin sensitivity and energy metabolism. This study demonstrated that the bTPP method can accelerate the field of biodiscovery, revealing protein targets involved in mechanisms of action (MOA) connected with future applications of bioactive compounds.This project received funding from the ERA-NET Marine Biotechnology project CYANOBESITY that it is cofounding from FORMAS, Sweden grant nr. 2016-02004 (SC), FCT Foundation of Science and Technology, Portugal, grant number ERA-MBT/0001/2015 (RU). This work has also been funded by IKERBASQUE (SC), Basque Government grant IT-971-16 (SC and OF), and FCT grants SFRH/BPD/112287/2015, SFRH/BD/116009/2016, FCT strategic fund (UID/Multi/04423/2019) (RU and SF)