The Effects of Neonatal Immune System Activation with Lipopolysaccharide on Adolescent and Adult Anxiety Behaviours in Male and Female Rats

The present study examined the effects of neonatal (postnatal days 3 and 5) acute immune system activation with lipopolysaccharide (LPS) on adolescent and adult anxiety behaviours. The major findings suggest that neonatal LPS does not have general long-lasting effects on adolescent anxiety and locomotor behaviours. Rather, early endotoxin treatment has highly specific effects on certain anxiety behaviours that vary depending on the development period. Moreover, neonatal LPS does not seem to influence adult voluntary and non-voluntary locomotor activity or anhedonia, independent of, or in response to, an adult immune challenge. Finally, sex differences were observed in various responses in adulthood, independent of neonatal drug treatment. The findings of this study provide a better understanding of adolescent and adult behavioural outcomes in response to endotoxin, and suggest that early exposure to pathogens may not be a significant risk factor in the general development of later anxiety disorders

Complexity and hierarchical game of life

Hierarchical structure is an essential part of complexity, important notion relevant for a wide range of applications ranging from biological population dynamics through robotics to social sciences. In this paper we propose a simple cellular-automata tool for study of hierarchical population dynamics

Waiting time phenomena forced by critical boundary conditions in classical diffusion problems

This paper revisits some very classical initial-boundary value problems for parabolic equations, providing simple examples in which the occurrence of flux discontinuities at the boundary when the unknown function reaches some critical value may give rise to a waiting time phenomenon. A physical interpretation could be a modification of the surface of the considered body taking place at the mentioned critical value, affecting the way the body interacts with the surroundings. The waiting time, whose length (finite or infinite) is a priori unknown allows the system to evolve gradually through the critical state. Some numerical simulations are also presented

Overlimiting Current and Shock Electrodialysis in Porous Media

Most electrochemical processes, such as electrodialysis, are limited by diffusion, but in porous media, surface conduction and electro-osmotic flow also contribute to ionic fluxes. In this paper, we report experimental evidence for surface-driven over-limiting current (faster than diffusion) and deionization shocks (propagating salt removal) in a porous medium. The apparatus consists of a silica glass frit (1 mm thick with 500 nm mean pore size) in an aqueous electrolyte (CuSO$_4$ or AgNO$_3$) passing ionic current from a reservoir to a cation-selective membrane (Nafion). The current-voltage relation of the whole system is consistent with a proposed theory based on the electro-osmotic flow mechanism over a broad range of reservoir salt concentrations (0.1 mM - 1.0 M), after accounting for (Cu) electrode polarization and pH-regulated silica charge. Above the limiting current, deionized water ($\approx 10 \mu$ $M$) can be continuously extracted from the frit, which implies the existence of a stable shock propagating against the flow, bordering a depleted region that extends more than 0.5mm across the outlet. The results suggest the feasibility of "shock electrodialysis" as a new approach to water desalination and other electrochemical separations.Comment: 39 pages, 9 fig

Effect of concentration polarization on permselectivity

In this paper, the variation of permselectivity in the course of concentration polarization is systematically analyzed for a three-layer membrane system consisting of a nonperfectly permselective ion exchange membrane, homogeneous or heterogeneous, flanked by two diffusion layers of a binary univalent electrolyte. For a heterogeneous membrane, an ionic transport model is proposed, which is amenable to analytical treatment. In this model, assuming a constant fixed charge in the membrane and disregarding water splitting, the entire transport problem is reduced to solution of a single algebraic equation for the counterion transport number. It is concluded that for both types of membrane the concentration polarization may significantly affect the permselectivity of the system through the effects of the induced nonuniformity of the coion diffusion flux in the membrane (convexity of the coion concentration profile) and varying membrane-solution interface concentration. While the former is significant for low membrane fixed charge density, for a heterogeneous membrane, the latter might be considerably affected by the flux focusing effect at the permeable membrane segments.United States-Israel Binational Science Foundation (Grant 2010199

Electro-osmotic Instability of Concentration Enrichment in Curved Geometries for an Aqueous Electrolyte

We report that an electro-osmotic instability of concentration enrichment in curved geometries for an aqueous electrolyte, as opposed to the well-known one, is initiated exclusively at the enriched interface (anode), rather than at the depleted one (cathode). For this instability, the limitation of unrealistically high material Peclet number in planar geometry is eliminated by the strong electric field arising from the line charge singularity. In a model setup of concentric circular electrodes, we show by stability analysis, numerical simulation, and experimental visualization that instability occurs at the inner anode, below a critical radius of curvature. The stability criterion is also formulated in terms of a critical electric field and extended to arbitrary (2d) geometries by conformal mapping. This discovery suggests that transport may be enhanced in processes limited by salt enrichment, such as reverse osmosis, by triggering this instability with needle-like electrodes.Comment: 5 pages, 4 figure

Lo spirito del male

In questo volume Nathalie Zaltzman -membro fondatore del IV Gruppo e co-redattrice della Rivista Topique- esplora il rapporto tra il Kulturarbeit e la dimensione del male, presentandoci il progredire di una riflessione da lungo tempo praticata sulle questioni della civilizzazione e delle sue oscurità. Avvalendosi di appassionanti incursioni nella letteratura, con un procedere dialettico dell’argomentazione in cui le domande sono veri strumenti di pensiero e con una prosa dialogica e a tratti spumeggiante, Zaltzman ci mostra i punti di vulnerabilità del Kulturarbeit, alla ricerca di una leva in grado di scardinare quella resilienza della dimensione del male refrattaria ad ogni progresso di civiltà. Il movimento è circolare: dopo aver isolato le due direzioni di analisi freudiana -civilizzazione e Kulturarbeit- che vanno a tessere la trama del saggio, si entra nel vivo della questione sullo spirito del male che dopo un lungo détour esplorativo -sul rapporto tra le rappresentazioni dell’umano, il progresso dell’opera di civiltà rivelato dalla nascita della nozione di crimine contro l’umanità e la dimensione del male-, viene ripresa ed arricchita dalla proposta di una topica del male. La problematica in gioco, la cui complessità apre più questioni di quante ne possa risolvere -come segnalato dalla scelta di titolare i due ultimi capitoli: Perplessità-, sembra trovare una sortita nel mantenimento del focus sul legame tra ontogenetico e filogenetico, tra individuale e collettivo