Dynamic polarizability of rotating particles in electrorheological fluids

A rotating particle in electrorheological (ER) fluid leads to a displacement of its polarization charges on the surface which relax towards the external applied field ${\bf E}_0$, resulting in a steady-state polarization at an angle with respect to ${\bf E}_0$. This dynamic effect has shown to affect the ER fluids properties dramatically. In this paper, we develop a dynamic effective medium theory (EMT) for a system containing rotating particles of finite volume fraction. This is a generalization of established EMT to account for the interactions between many rotating particles. While the theory is valid for three dimensions, the results in a special two dimensional configuration show that the system exhibits an off-diagonal polarization response, in addition to a diagonal polarization response, which resembles the classic Hall effect. The diagonal response monotonically decreases with an increasing rotational speed, whereas the off-diagonal response exhibits a maximum at a reduced rotational angular velocity $\omega_0$ comparing to the case of isolated rotating particles. This implies a way of measurement on the interacting relaxation time. The dependencies of the diagonal and off-diagonal responses on various factors, such as $\omega_0$, the volume fraction, and the dielectric contrast, are discussed.Comment: 6 pages, 4 figures, accepted to J. Phys. Chem.

Global respiratory syncytial virus–related infant community deaths

Background Respiratory syncytial virus (RSV) is a leading cause of pediatric death, with >99% of mortality occurring in low- and lower middle-income countries. At least half of RSV-related deaths are estimated to occur in the community, but clinical characteristics of this group of children remain poorly characterized. Methods The RSV Global Online Mortality Database (RSV GOLD), a global registry of under-5 children who have died with RSV-related illness, describes clinical characteristics of children dying of RSV through global data sharing. RSV GOLD acts as a collaborative platform for global deaths, including community mortality studies described in this supplement. We aimed to compare the age distribution of infant deaths <6 months occurring in the community with in-hospital. Results We studied 829 RSV-related deaths <1 year of age from 38 developing countries, including 166 community deaths from 12 countries. There were 629 deaths that occurred <6 months, of which 156 (25%) occurred in the community. Among infants who died before 6 months of age, median age at death in the community (1.5 months; IQR: 0.8−3.3) was lower than in-hospital (2.4 months; IQR: 1.5−4.0; P < .0001). The proportion of neonatal deaths was higher in the community (29%, 46/156) than in-hospital (12%, 57/473, P < 0.0001). Conclusions We observed that children in the community die at a younger age. We expect that maternal vaccination or immunoprophylaxis against RSV will have a larger impact on RSV-related mortality in the community than in-hospital. This case series of RSV-related community deaths, made possible through global data sharing, allowed us to assess the potential impact of future RSV vaccines

Abstract Location Updating Strategies in Moving Object Databases

com Recent advances in wireless, communication systems have led to important new applications of Moving object databases (MOD). Typical application examples of moving object databases (MOD) might include mobile computing, mobile E-Commerce, Traffic police, taxi dispatchers and weather reporting services. The mobile computing capabilities allow users to manage their work while they are moving. In order to manage such moving objects in database management systems (DBMS) an updating strategy for moving object is required. In the literature there are many location updating polices. The dead-reckoning policy is the most common updating strategy for moving object. This policy can be divided into two major classes, namely the plain dead-reckoning (pdr) and adaptive dead-reckoning (adr). In this paper the problem of maintaining the current location of moving object in databases and the required updating strategy for moving object will be investigated. An implementation of deviation updating strategy will be introduced. This implementation is based on the generation of spatial-temporal data for the moving objects (e.g. cars).Where the moving objects are moving through a network street. Finally a complete comparison of the predicted moving object path and the actual path is given