onsumer instant messaging (CIM) services (aka public IM) such as AOL Messenger, Yahoo! Messenger, and MSN Messenger have achieved critical mass appeal and usage as a convenient and informal method of communication supporting real-time messaging and presence awareness.1,2 Unfortunately, these services are highly vulnerable from a security standpoint. Some of these security problems include threa...

In this study, we investigate the problems of inhomogeneous turbulence. The main goal has been to find the connections between analytic turbulence theories, notably the formalism of the direct interaction approximation (DIA), and turbulence phenomenology. To simplify the results from an inhomogeneous DIA model, we have employed a diagonalization procedure and an assumption of weak inhomogeneity...

La hiperamonemia aguda (HAA) es una urgencia médica que causa daño neurológico y puede conducir a o incluso la muerte. En los pacientes con errores innatos del metabolismo (EIM) se presenta mayor frecuencia, sobre todo en eventos de descompensación metabólica, ameritando atención terapia intensiva. Los EIM principalmente causan HAA incluyen defectos ciclo urea, acidemias orgánicas, oxidación ác...

backgrounds and objectives: the dispersion of particulate matter has been known as the most serious environmental pollution of cement plants. in the present work, dispersion of the particulate matter from stack of kerman cement plant was investigated using computational fluid dynamics (cfd) modeling.materials and methods: in order to study the dispersion of particulate matter from the stack, a ...

The modulation of the North Pacific storm track by tropical convection on intraseasonal time scales (30– 90 days) in boreal winter (December–March) is investigated using the NCEP–NCAR reanalysis and NOAA satellite outgoing longwave radiation (OLR) data. Multivariate empirical orthogonal function (MEOF) analysis and case compositing based upon the principal components (PCs) of the EOFs reveal su...

[1] In this study, scale interaction between synoptic eddies and low-frequency flow is investigated. The synoptic eddy feedback is a key process in sustaining the low-frequency flow. We show clear evidence using NCEP reanalysis data that there is a general underlying rule—the ‘‘left-hand rule’’, governing the synoptic eddy feedback onto low-frequency flow. This rule states that eddy-vorticity f...

Hurricane Opal (1995) crossed the Gulf of Mexico rapidly intensifying to a 130-kt storm, then fortunately weakening before landfall on the Florida panhandle. This intensification was underforecast by the National Hurricane Center. Forecast fields from the 1997 version of the Geophysical Fluid Dynamics Laboratory Hurricane Prediction System (GFDL model) for Hurricane Opal are used to diagnose th...

The dynamical interaction between eddies and shear flow is investigated through a simplified model of vorticity conservation with tilted eddies. Energy is transfered either to the flow or to eddies, depending on the eddy tilt with respect to the flow shear. When eddies are tilted in the shear direction, the system is favorable to shear increase: tilt instability or negative viscosity phenomenon...

The accuracy of large-eddy simulations is limited, among others, by the quality of the subgrid parameterisation and the numerical contamination of the smaller retained flow structures. We review the effects of discretisation and modelling errors from two different perspectives. We first show that spatial discretisation induces its own filter and compare the dynamic importance of this numerical ...