Using two climate-vegetation model simulations from the Fast Ocean Atmosphere Model (FOAM) and the Community Climate System Model (CCSM, version 2), we investigate vegetation-precipitation feedbacks across North Africa during the mid-Holocene. From mid-Holocene snapshot runs of FOAM and CCSM2, we detect a negative feedback at the annual timescale with our statistical analysis. Using the Monte- Carlo bootstrap method, the annual negative feedback is further confirmed to be significant in both simulations. Additional analysis shows that this negative interaction is partially caused by the competition between evaporation and transpiration in North African grasslands. Furthermore, we find the feedbacks decrease with increasing timescales, and change signs from positive to negative at increasing timescales in FOAM. The proposed mechanism for this sign switch is associated with the different persistent timescales of upper and lower soil water contents, and their interactions with vegetation and atmospheric precipitation.

In order to create a successful grid infrastructure, sites and resource providers must be able to publish information about their underlying resources and services. This information makes it easier for users and virtual organizations to make intelligent decisions about resource selection and scheduling, and can be used by the grid infrastructure for accounting and troubleshooting services. However, such an outbound stream may include data deemed sensitive by a resource-providing site, exposing potential security vulnerabilities or private user information to the world at large, including malicious entities. This study analyzes the various vectors of information being published from sites to grid infrastructures. In particular, it examines the data being published to, and collected by the Open Science Grid, including resource selection, monitoring, accounting, troubleshooting, logging and site verification data. We analyze the risks and potential threat models posed by the publication and collection of such data. We also offer some recommendations and best practices for sites and grid infrastructures to manage and protect sensitive data.