Super-lattice, rhombus, square, and hexagonal standing waves in magnetically driven ferrofluid surface

Standing wave patterns that arise on the surface of ferrofluids by (single frequency) parametric forcing with an ac magnetic field are investigated experimentally. Depending on the frequency and amplitude of the forcing, the system exhibits various patterns including a superlattice and subharmonic rhombuses as well as conventional harmonic hexagons and subharmonic squares. The superlattice arises in a bicritical situation where harmonic and subharmonic modes collide. The rhombic pattern arises due to the non-monotonic dispersion relation of a ferrofluid

The emotional review–reward effect: how do reviews increase impulsivity?

A growing reliance on customer reviews prompts firms to develop strategies to encourage customers to post online reviews of their products. However, little research investigates the behavioral consequences of writing a review. The act of sharing personal opinions through reviews is a rewarding experience and makes customers feel socially connected. With an application of reverse alliesthesia theory, the current study predicts that such rewarding experiences drive online reviewers to seek other rewards, such as impulsive buying. Three lab-based and two field studies demonstrate such an emotional review–reward effect: sharing emotional inf ormation in the public realm of customer reviews, rather than forming similar opinions privately, drives participants to make more impulsive buying decisions

Live attenuated influenza viruses produced in a suspension process with avian AGE1.CR.pIX cells

Background: Current influenza vaccines are trivalent or quadrivalent inactivated split or subunit vaccines administered intramuscularly, or live attenuated influenza vaccines (LAIV) adapted to replicate at temperatures below body temperature and administered intranasally. Both vaccines are considered safe and efficient, but due to differences in specific properties may complement each other to ensure reliable vaccine coverage. By now, licensed LAIV are produced in embryonated chicken eggs. In the near future influenza vaccines for human use will also be available from adherent MDCK or Vero cell cultures, but a scalable suspension process may facilitate production and supply with vaccines. Results: We evaluated the production of cold-adapted human influenza virus strains in the duck suspension cell line AGE1.CR.pIX using a chemically-defined medium. One cold-adapted A (H1N1) and one cold-adapted B virus strain was tested, as well as the reference strain A/PR/8/34 (H1N1). It is shown that a medium exchange is not required for infection and that maximum virus titers are obtained for 1x10-6 trypsin units per cell. 1 L bioreactor cultivations showed that 4x106 cells/mL can be infected without a cell density effect achieving titers of 1x108 virions/mL after 24 h. Conclusions: Overall, this study demonstrates that AGE1.CR.pIX cells support replication of LAIV strains in a chemically-defined medium using a simple process without medium exchanges. Moreover, the process is fast with peak titers obtained 24 h post infection and easily scalable to industrial volumes as neither microcarriers nor medium replacements are required. © 2012 Lohr et al.; licensee BioMed Central Ltd. [accessed 2013 November 18th

Cutting through Content Clutter: How Speech and Image Acts Drive Consumer Sharing of Social Media Brand Messages

Consumer-to-consumer brand message sharing is pivotal for effective social media marketing. Even as companies join social media conversations and generate millions of brand messages, it remains unclear what, how, and when brand messages stand out and prompt sharing by consumers. With a conceptual extension of speech act theory, this study offers a granular assessment of brands’ message intentions (i.e., assertive, expressive, or directive) and the effects on consumer sharing. A text mining study of more than two years of Facebook posts and Twitter tweets by well-known consumer brands empirically demonstrates the impacts of distinct message intentions on consumers’ message sharing. Specifically, the use of rhetorical styles (alliteration and repetitions) and cross-message compositions enhance consumer message sharing. As a further extension, an image-based study demonstrates that the presence of visuals, or so-called image acts, increases the ability to account for message sharing. The findings explicate brand message sharing by consumers and thus offer guidance to content managers for developing more effective conversational strategies in social media marketing

Take their word for it: The symbolic role of linguistic style matches in user communities

User communities are increasingly becoming an essential element of companies' business processes. However, reaping the benefits of such social systems does not always prove effective, often because companies fail to stimulate members' collaboration continuously or neglect their social integration. Following communication accommodation theory, the authors posit that members' communication style alignment symbolically reflects their community identification and affects subsequent participation behavior. This research uses text mining to extract the linguistic style properties of 74,246 members' posts across 37 user communities. Two mixed multilevel Poisson regression models show that when members' linguistic style matches with the conventional community style, it signals their community identification and affects their participation quantity and quality. Drawing on an expanded view of organizational identification, the authors consider dynamics in members' social identification by examining trends and reversals in linguistic style match developments. Whereas a stronger trend of alignment leads to greater participation quantity and quality, frequent reversals suggest lower participation quantity. At a community level, greater synchronicity in the linguistic style across all community members fosters individual members' participation behavior

Leptospirosis followed by Kawasaki-like disease: case report from an adult Swiss patient and review of the literature

Kawasaki disease (KD) is a vasculitis that mostly occurs in children, but rare cases in adults have been reported. We describe the case of a 43-year-old Swiss male who developed symptoms compatible with KD 7 weeks after leptospirosis, which was presumably acquired after swimming in a creek in the Swiss Alps. We performed a literature review and identified 10 other cases (all in children), in which Kawasaki-like disease was diagnosed in the context of leptospirosis. Outcome was favourable in most cases, including our patient. This exceptional case demonstrates both the possibility of autochthonous cases of leptospirosis in Switzerland as well as a possible association of leptospirosis with Kawasaki-like disease

Logics of Finite Hankel Rank

We discuss the Feferman-Vaught Theorem in the setting of abstract model theory for finite structures. We look at sum-like and product-like binary operations on finite structures and their Hankel matrices. We show the connection between Hankel matrices and the Feferman-Vaught Theorem. The largest logic known to satisfy a Feferman-Vaught Theorem for product-like operations is CFOL, first order logic with modular counting quantifiers. For sum-like operations it is CMSOL, the corresponding monadic second order logic. We discuss whether there are maximal logics satisfying Feferman-Vaught Theorems for finite structures.Comment: Appeared in YuriFest 2015, held in honor of Yuri Gurevich's 75th birthday. The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-23534-9_1

Critical exponents of directed percolation measured in spatiotemporal intermittency

A new experimental system showing a transition to spatiotemporal intermittency is presented. It consists of a ring of hundred oscillating ferrofluidic spikes. Four of five of the measured critical exponents of the system agree with those obtained from a theoretical model of directed percolation.Comment: 7 pages, 12 figures, submitted to PR

Wave Number of Maximal Growth in Viscous Magnetic Fluids of Arbitrary Depth

An analytical method within the frame of linear stability theory is presented for the normal field instability in magnetic fluids. It allows to calculate the maximal growth rate and the corresponding wave number for any combination of thickness and viscosity of the fluid. Applying this method to magnetic fluids of finite depth, these results are quantitatively compared to the wave number of the transient pattern observed experimentally after a jump--like increase of the field. The wave number grows linearly with increasing induction where the theoretical and the experimental data agree well. Thereby a long-standing controversy about the behaviour of the wave number above the critical magnetic field is tackled.Comment: 19 pages, 15 figures, RevTex; revised version with a new figure and references added. submitted to Phys Rev