We consider the kinetic Cucker-Smale model with local alignment as a mesoscopic description for the flocking dynamics. The local alignment was first proposed by Karper, Mellet and Trivisa [29], as a singular limit of a normalized non-symmetric alignment introduced by Motsch and Tadmor [32]. The existence of weak solutions to this model is obtained in [29]. The time-asymptotic flocking behavior is shown in this article. Our main contribution is to provide a rigorous derivation from mesoscopic to macroscopic description for the Cucker-Smale flocking models. More precisely, we prove the hydrodynamic limit of the kinetic Cucker-Smale model with local alignment towards the pressureless Euler system with nonlocal alignment, under a regime of strong local alignment. Based on the relative entropy method, a main difficulty in our analysis comes from the fact that the entropy of the limit system has no strict convexity in terms of density variable. To overcome this, we combine relative entropy quantities with the 2-Wasserstein distance.

bThe accumulation of viral RNA depends on many host cellular factors. The hexagonal peroxisome (Hex1) protein is a fungal protein that is highly expressed when the DK21 strain of Fusarium graminearum virus 1 (FgV1) infects its host, and Hex1 affects the accumulation of FgV1 RNA. The Hex1 protein is the major constituent of the Woronin body (WB), which is a peroxisome-derived electron-dense core organelle that seals the septal pore in response to hyphal wounding. To clarify the role of Hex1 and the WB in the relationship between FgV1 and Fusarium graminearum, we generated targeted gene deletion and overexpression mutants. Although neither HEX1 gene deletion nor overexpression substantially affected vegetative growth, both changes reduced the production of asexual spores and reduced virulence on wheat spikelets in the absence of FgV1 infection. However, the vegetative growth of deletion and overexpression mutants was increased and decreased, respectively, upon FgV1 infection compared to that of an FgV1-infected wild-type isolate. Viral RNA accumulation was significantly decreased in deletion mutants but was significantly increased in overexpression mutants compared to the viral RNA accumulation in the virus-infected wild-type control. Overall, these data indicate that the HEX1 gene plays a direct role in the asexual reproduction and virulence of F. graminearum and facilitates viral RNA accumulation in the FgV1-infected host fungus.T he interactions between viral elements and host factors are important for maintaining the infection cycles of RNA viruses in host cells. Viruses utilize numerous host factors that play essential roles in virus infection. Therefore, understanding the role(s) of host factors can provide insight into the molecular mechanism(s) of host and virus interactions. Relative to host factors affecting RNA viruses of animals and plants, host factors affecting fungal viruses (mycoviruses) are poorly understood.Several host and viral components required for virus life in cells have been identified and characterized in the model organism Saccharomyces cerevisiae. The knowledge obtained by studying S. cerevisiae as a host for several double-stranded RNA (dsRNA) and single-stranded RNA (ssRNA) viruses has greatly extended our understanding of mycovirus-host interaction (1). With respect to filamentous fungi, the host factors required for mycovirus replication and symptom induction have been well described for the interaction between the prototypic hypovirus Cryphonectria hypovirus 1 strain EP713 (CHV1) and its host, the chestnut blight fungus (Cryphonectria parasitica). One of these host factors, NAM-1, modulates symptom induction in the fungus in response to CHV1 infection (2). The hypovirus-responsive host transcription factor gene pro1 is required for female fertility of C. parasitica, development of its asexual spores, and the maintenance of CHV1 infection (3). The host gene Cpbir1 (bir1 of C. parasitica), which encodes the IAP (inhibitor of apoptosis protein) CpBir1 and which is required for fungal...

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Abstract. We study the contraction properties (up to shift) for admissible RankineHugoniot discontinuities of n × n systems of conservation laws endowed with a convex entropy. We first generalize the criterion developed in [47], using the spatially inhomogeneous pseudo-distance introduced in [50]. Our generalized criterion guarantees the contraction property for extremal shocks of a large class of systems, including the Euler system. Moreover, we introduce necessary conditions for contraction, specifically targeted for intermediate shocks. As an application, we show that intermediate shocks of the two-dimensional isentropic magnetohydrodynamics do not verify any of our contraction properties. We also investigate the contraction properties, for contact discontinuities of the Euler system, for a certain range of contraction weights. All results do not involve any smallness condition on the initial perturbation, nor on the size of the shock.