A minimal stochastic model for influenza evolution

We introduce and discuss a minimal individual-based model for influenza dynamics. The model takes into account the effects of specific immunization against viral strains, but also infectivity randomness and the presence of a short-lived strain transcending immunity recently suggested in the literature. We show by simulations that the resulting model exhibits substitution of viral strains along the years, but that their divergence remains bounded. We also show that dropping any of these features results in a drastically different behavior, leading either to the extinction of the disease, to the proliferation of the viral strains, or to their divergence

Pemanfaatan Tempat Pendaratan Ikan (Tpi) di Kecamatan Rangsang Kabupaten Kepulauan Meranti

Building Fish Landing Places (TPI) that ther stimuli are buildings constructed for thefishermen land their catch of fish. These buildings have been built but not yet enabled bythe local government, especially the Department of Marine and Fisheries Meranti IslandsRegency. This is because the Department has the authority to regulate and supervise theactivities of marine and fisheries. Peneliitian purpose of this is to know the problemsfaced by the Department of Marine and Fisheries in the functioning of Fish LandingPlaces (TPI).Arrangement is to create a way to make a pekerjan have goals, direction to be achieved,sby knowing the existing procedures. This study used a qualitative descriptive method.Data were obtained from the interview data, documentary studies, and field observations.Informants in this study are those relating to the discussion of the function of FishLanding Places (TPI) is.The results showed that in the discussion of the function of pemanfaataan Fish LandingPlaces (TPI) is not able to function because of the absence of directives from the centralgovernment to the regions, and because of inadequate facilities. Furthermore, theconstraints for the fishermen are long distance and weather influences.Keywords. Place Pendaratn Fish, Function Department, Local Governmen

Electrical modeling of the photoelectric effect induced by a pulsed laser applied to an SRAM cell

International audienceThis abstract presents an electrical model of an SRAM cell exposed to a pulsed Photoelectrical Laser Stimulation (PLS), based on our past model of MOS transistor under laser illumination. The validity of our model is assessed by the very good correlation obtained between measurements and electrical simulation. These simulations are capable to explain some specific points. For example, in theory, a SRAM cell under PLS have four sensitive areas. But in measurements only three areas were revealed. A hypothesis was presented in this paper and confirm by electrical simulation. The specific topology of the cell masks one sensitive area. Therefore the electrical model could be used as a tool of characterization of a CMOS circuits under PLS

On the accuracy of language trees

Historical linguistics aims at inferring the most likely language phylogenetic tree starting from information concerning the evolutionary relatedness of languages. The available information are typically lists of homologous (lexical, phonological, syntactic) features or characters for many different languages. From this perspective the reconstruction of language trees is an example of inverse problems: starting from present, incomplete and often noisy, information, one aims at inferring the most likely past evolutionary history. A fundamental issue in inverse problems is the evaluation of the inference made. A standard way of dealing with this question is to generate data with artificial models in order to have full access to the evolutionary process one is going to infer. This procedure presents an intrinsic limitation: when dealing with real data sets, one typically does not know which model of evolution is the most suitable for them. A possible way out is to compare algorithmic inference with expert classifications. This is the point of view we take here by conducting a thorough survey of the accuracy of reconstruction methods as compared with the Ethnologue expert classifications. We focus in particular on state-of-the-art distance-based methods for phylogeny reconstruction using worldwide linguistic databases. In order to assess the accuracy of the inferred trees we introduce and characterize two generalizations of standard definitions of distances between trees. Based on these scores we quantify the relative performances of the distance-based algorithms considered. Further we quantify how the completeness and the coverage of the available databases affect the accuracy of the reconstruction. Finally we draw some conclusions about where the accuracy of the reconstructions in historical linguistics stands and about the leading directions to improve it.Comment: 36 pages, 14 figure

Modeling microevolution in a changing environment: The evolving quasispecies and the Diluted Champion Process

Several pathogens use evolvability as a survival strategy against acquired immunity of the host. Despite their high variability in time, some of them exhibit quite low variability within the population at any given time, a somehow paradoxical behavior often called the evolving quasispecies. In this paper we introduce a simplified model of an evolving viral population in which the effects of the acquired immunity of the host are represented by the decrease of the fitness of the corresponding viral strains, depending on the frequency of the strain in the viral population. The model exhibits evolving quasispecies behavior in a certain range of its parameters, ans suggests how punctuated evolution can be induced by a simple feedback mechanism.Comment: 15 pages, 12 figures. Figures redrawn, some additional clarifications in the text. To appear in Journal of Statistical Mechanics: Theory and Experimen

Off-shore and underwater sampling of aquatic environments with the aerial-aquatic drone MEDUSA

Monitoring of aquatic habitats for water quality and biodiversity requires regular sampling, often in off-shore locations and underwater. Such sampling is commonly performed manually from research vessels, or if autonomous, is constrained to permanent installations. Consequentially, high frequency ecological monitoring, such as for harmful algal blooms, are limited to few sites and/or temporally infrequent. Here, we demonstrate the use of MEDUSA, an Unmanned Aerial-Aquatic Vehicle which is capable of performing underwater sampling and inspection at up to 10 m depth, and is composed of a multirotor platform, a tether management unit and a tethered micro Underwater Vehicle. The system is validated in the task of vertical profiling of Chlorophyll-a levels in freshwater systems by means of a custom solid sample filtering mechanism. This mechanism can collect up to two independent samples per mission by pumping water through a pair of glass-fibre GF/F filters. Chlorophyll levels measured from the solid deposits on the filters are consistent and on par with traditional sampling methods, highlighting the potential of using UAAVs to sample aquatic locations at high frequency and high spatial resolution

Permeability of anti-fouling PEGylated surfaces probed by fluorescence correlation spectroscopy

The present work reports on in situ observations of the interaction of organic dye probe molecules and dye-labeled protein with different poly(ethylene glycol) (PEG) architectures (linear, dendron, and bottle brush). Fluorescence correlation spectroscopy (FCS) and single molecule event analysis were used to examine the nature and extent of probe朠EG interactions. The data support a sieve-like model in which size-exclusion principles determine the extent of probe朠EG interactions. Small probes are trapped by more dense PEG architectures and large probes interact more with less dense PEG surfaces. These results, and the tunable pore structure of the PEG dendrons employed in this work, suggest the viability of electrochemically-active materials for tunable surfaces