A discrete time neural network model with spiking neurons II. Dynamics with noise

We provide rigorous and exact results characterizing the statistics of spike trains in a network of leaky integrate and fire neurons, where time is discrete and where neurons are submitted to noise, without restriction on the synaptic weights. We show the existence and uniqueness of an invariant measure of Gibbs type and discuss its properties. We also discuss Markovian approximations and relate them to the approaches currently used in computational neuroscience to analyse experimental spike trains statistics.Comment: 43 pages - revised version - to appear il Journal of Mathematical Biolog

A view of Neural Networks as dynamical systems

We consider neural networks from the point of view of dynamical systems theory. In this spirit we review recent results dealing with the following questions, adressed in the context of specific models. 1. Characterizing the collective dynamics; 2. Statistical analysis of spikes trains; 3. Interplay between dynamics and network structure; 4. Effects of synaptic plasticity.Comment: Review paper, 51 pages, 10 figures. submitte

Evaluation and phylogenetic analysis of regular rabies virus vaccine strains

Background: This study aimed to evaluate Rabies virus vaccine strains. The obtained results may be helpful for vaccine producers and researchers to compare the strains with wild type and other vaccine strains and select the correct strain to challenge their products. Methods: Fourteen rabies virus vaccine strains were compared with each other. The full genomes of the selected strains were taken from the GenBank and the N, P and G genes were labeled. The major and minor antigenic sites of these sequences were identified and contrasted with each other. The identity matrix was designed for rabies virus full genome, N and G genes. In addition, the phylogenetic tree was drawn based on rabies virus N gene for deep analysis. Results: Although there were no significant differences between antigenic sites in N, P, and G genes, there were noticeable differences for full genome identity matrix and this significant difference can also be observed in N and G identity matrix. In the phylogenetic tree, the Iranian sequences were distant from currently applied vaccine strains. Conclusion: It is necessary to pay attention to the results shown in phylogenetic tree because they warn us about distance between the Iranian sequences and current strains used in applied vaccines. In addition, the obtained results help vaccine producers to choose a correct strain to challenge their product and evaluate their vaccine potency. © 2018 The Author(s)

Evaluation and Phylogenetic Analysis of Regular Rabies Virus Vaccine Strains

Background: This study aimed to evaluate Rabies virus vaccine strains. The obtained results may be helpful for vaccine producers and researchers to compare the strains with wild type and other vaccine strains and select the correct strain to challenge their products.Methods: Fourteen rabies virus vaccine strains were compared with each other. The full genomes of the selected strains were taken from the GenBank and the N, P and G genes were labeled. The major and minor antigenic sites of these sequences were identified and contrasted with each other. The identity matrix was designed for rabies virus full genome, N and G genes. In addition, the phylogenetic tree was drawn based on rabies virus N gene for deep analysis.Results: Although there were no significant differences between antigenic sites in N, P, and G genes, there were noticeable differences for full genome identity matrix and this significant difference can also be observed in N and G identity matrix. In the phylogenetic tree, the Iranian sequences were distant from currently applied vaccine strains.Conclusion: It is necessary to pay attention to the results shown in phylogenetic tree because they warn us about distance between the Iranian sequences and current strains used in applied vaccines. In addition, the obtained results help vaccine producers to choose a correct strain to challenge their product and evaluate their vaccine potency

The overwintering of Antarctic krill, Euphausia superba, from an ecophysiological perspective

A major aim of this review is to determine which physiological functions are adopted by adults and larvae to survive the winter season with low food supply and their relative importance. A second aim is to clarify the extent to which seasonal variation in larval and adult krill physiology is mediated by environmental factors with a strong seasonality, such as food supply or day light. Experimental studies on adult krill have demonstrated that speciWc physiological adaptations during autumn and winter, such as reduced metabolic rates and feeding activity, are not caused simply by the scarcity of food, as was previously assumed. These adaptations appear to be inXuenced by the local light regime. The physiological functions that larval krill adopt during winter (reduced metabolism, delayed development, lipid utilisation, and variable growth rates) are, in contrast to the adults, under direct control by the available food supply. During winter, the adults often seem to have little association with sea ice (at least until early spring). The larvae, however, feed within sea ice but mainly on the grazers of the ice algal community rather than on the algae themselves. In this respect, a miss-match in timing of the occurrence of the last phytoplankton blooms in autumn and the start of the sea ice formation, as has been increasingly observed in the west Antarctic Peninsula (WAP) region, will impact larval krill development during winter in terms of food supply and consequently the krill stock in this region

Physiology of Euphausia superba

Since the 1920s, E. superba is one of the best studied species in the Southern Ocean in terms of their general biology. The main driver for this research focus has been the fisheries’ requirements for stock forecasting and conservation measures. Nowadays this is joined by concerns over climate change effects and the requirement to take a more holistic over view to understand food web structures. So far, however, we do not have a clear understanding of the physiological response of krill and hence their adaptability to cope with ongoing environmental changes, caused by the anthropogenic carbon emissions. This is due to the extreme lack of intense studies on krill physiology, especially of their larval stages in relation to their seasonal environment. A major aim of this book chapter is on the one hand to summaries how physiological functions such as lipid accumulation and utilisation, metabolic activity and growth change with ontogeny and season and to demonstrate which environmental factors are the main drivers for seasonal variability of these functions in adult and larval krill. On the other hand, we draw the attention to the importance of photoperiod (day length) as an entrainment cue for endogenous rhythms and clocks in the life cycle of krill. Furthermore, we give an overview of the current knowledge on the impact of elevated seawater temperature and ocean acidification on krill

Zooplankton II. Macroplankton and Long-Term Series

International audienc