Global regularity properties of steady shear thinning flows

In this paper we study the regularity of weak solutions to systems of p-Stokes type, describing the motion of some shear thinning fluids in certain steady regimes. In particular we address the problem of regularity up to the boundary improving previous results especially in terms of the allowed range for the parameter p

Site Selection For Oyster Habitat Rehabilitation In The Virginia Portion Of The Chesapeake Bay: A Commentary

A significant body of knowledge has been generated during the past decade on disease tolerance of the native oyster Crassostrea virginica. A major opportunity to move into a large-scale field application phase of that knowledge has been presented by a 10-y commitment by the U.S. Army Corps of Engineers (ACOE) to a partnership in Virginia focused on widespread restoration of oyster resources for ecological purposes. The partnership involves ACOE, the Virginia Institute of Marine Science (VIMS), the Virginia Marine Resources Commission (VMRC), and the Chesapeake Bay Foundation (CBF). This collaboration will effect a sequenced restoration effort involving site selection, site restoration. brood stock addition from known genetic lines, evaluation of the stock in the new location for disease tolerance and/or contribution to Cumulative recruitment, and, through adaptive management, will seek to optimize the widespread restoration of the oyster populations in Virginia. This contribution focuses on the importance of site selection in this effort, paying particular attention to the roles of (1) demographics and disease status on fecundity of brood stock, (2) larval feeding and growth rate in high-turbidity conditions typical of low-salinity sanctuaries from disease, (3) ontogenetic changes in larval behavior in such conditions, and (4) the role of estuarine circulation in retaining larvae in regions suitable for subsequent recruitment. We argue that while efforts to develop disease-tolerant brood stock may contribute to restoration efforts. without parallel guiding knowledge of items 1-4 above. efforts at restoration will at best be serendipitous, at worst be doomed to failure, and that site selection in restoration is crucial to success

#ShamimaBegum: An analysis of social media narratives relating to female terrorist actors

This study explores the constructions of gender in social media narratives regarding Shamima Begum, a British born woman who travelled to Syria to join Islamic State of Iraq and Syria (ISIS). Using the Twitter hashtag #ShamimaBegum – developed in response to Begum’s expressed interest in returning to the United Kingdom to give birth to her third child – we employ critical discourse analysis to examine social media users’ responses to Begum’s case across a 3-week period. We portray how the vernacular narratives constructing femininity, gender, and their relation to terrorist activity are built on the expectation that the female actor should express remorse for her actions and is judged according to certain perceptions of maternalism, religion, and victimhood. We also explore the absence of considered agency in the narratives about women engaging in and disengaging from violent activities, demonstrating the weight of race, religion, and gender in shaping narratives surrounding perceived violent women.info:eu-repo/semantics/acceptedVersio

Rapid Spatial Learning Controls Instinctive Defensive Behavior in Mice

Instinctive defensive behaviors are essential for animal survival. Across the animal kingdom, there are sensory stimuli that innately represent threat and trigger stereotyped behaviors such as escape or freezing [1–4]. While innate behaviors are considered to be hard-wired stimulus-responses [5], they act within dynamic environments, and factors such as the properties of the threat [6–9] and its perceived intensity [1, 10, 11], access to food sources [12–14], and expectations from past experience [15, 16] have been shown to influence defensive behaviors, suggesting that their expression can be modulated. However, despite recent work [2, 4, 17–21], little is known about how flexible mouse innate defensive behaviors are and how quickly they can be modified by experience. To address this, we have investigated the dependence of escape behavior on learned knowledge about the spatial environment and how the behavior is updated when the environment changes acutely. Using behavioral assays with innately threatening visual and auditory stimuli, we show that the primary goal of escape in mice is to reach a previously memorized shelter location. Memory of the escape target can be formed in a single shelter visit lasting less than 20 s, and changes in the spatial environment lead to a rapid update of the defensive action, including changing the defensive strategy from escape to freezing. Our results show that although there are innate links between specific sensory features and defensive behavior, instinctive defensive actions are surprisingly flexible and can be rapidly updated by experience to adapt to changing spatial environments

Symmetry-Breaking and Percolation Transitions in a Surface Reaction Model with Superlattice Ordering

A symmetry-breaking order-disorder transition of the Ising type is found in a nonequilibrium surface reaction model for CO oxidation incorporating superlattice ordering of adsorbed oxygen. We relate this transition to the percolation of superlattice domains of oxygen, and discuss the consequences for chemical diffusion of coadsorbed CO. The latter constitutes a new type of problem involving transport in disordered media

Transitions between strongly correlated and random steady-states for catalytic CO-oxidation on surfaces at high-pressure

We explore simple lattice-gas reaction models for CO-oxidation on 1D and 2D periodic arrays of surface adsorption sites with CO adsorption and desorption, dissociative O2 adsorption and recombinative desorption (at low rate), and CO + O reaction to form CO2. Adspecies interactions are neglected, and adspecies diffusion is effectively absent. The models are motivated by studies of CO-oxidation on RuO2(110) at high-pressures. Despite the lack of adspecies interactions, negligible adspecies diffusion results in kinetically induced spatial correlations. A transition occurs from a random primarily CO-populated steady-state at high CO-partial pressure, pCO, to a strongly correlated near-O-covered steady-state for low pCO as noted by Matera et al. [J. Chem. Phys. 134, 064713 (2011)]. In addition, we identify a second transition to a random near-O-covered steady-state at very low pCO. Furthermore, we identify and analyze the slow diffusive dynamics for very low pCO and provide a detailed characterization of the crossover to the strongly correlated O-covered steady-state as well as of the spatial correlations in that state