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We present a method, called opportunistic scheduling, for exploiting the time-varying nature of the radio environment to increase the overall performance of the system under certain QoS/fairness requirements of users. We first introduce a general framework for opportunistic scheduling, and then identify three general categories of scheduling problems under(More)
Erythropoietin (EPO) is the principal growth factor regulating the production of circulating erythrocytes. We introduced null mutations into both Epo and the EPO receptor (EpoR) gene. Both heterozygotes appeared normal. Homozygous animals exhibited reduced primitive erythropoiesis and died around embryonic day 13, owing to failure of definitive fetal liver(More)
—In cognitive wireless networks where secondary users (SUs) opportunistically access spectral white spaces of primary users (PUs), there exists an inherent tradeoff between sensing and transmission due to the competing goals of PU protection and SU access maximization. This paper studies means of sensing-transmission for SUs to better manage the competing(More)
In this paper we investigate efficient strategies for supporting on-demand information dissemination and gathering in large-scale vwireless sensor networks. In particular, we propose a "comb-needle" discovery support model resembling an ancient method: use a comb to help find a needle in sands or a haystack. The model combines push and pull for information(More)
We consider wireless ad hoc networks with a large number of users. Subsets of users might be interested in identical information, and so we have a regime in which several multicast sessions may coexist. We first calculate an upper-bound on the achievable transmission rate per multicast flow as a function of the number of multicast sources in such a network.(More)
—Enabled by regulatory initiatives and radio technology advances, opportunistic spectrum access has the potential to mitigate spectrum scarcity and satisfy the increasing demand for spectrum. In this paper, we consider a scenario where secondary users can opportunistically access unused spectrum vacated by idle primaries. We introduce two metrics to protect(More)
Here we show that conditional deletion of Pten in a subpopulation of adult neural stem cells in the subependymal zone (SEZ) leads to persistently enhanced neural stem cell self-renewal without sign of exhaustion. These Pten null SEZ-born neural stem cells and progenies can follow the endogenous migration, differentiation, and integration pathways and(More)
Development of the central nervous system is controlled by both intrinsic and extrinsic signals that guide neuronal migration to form laminae. Although defects in neuronal mobility have been well documented as a mechanism for abnormal laminar formation, the role of radial glia, which provide the environmental cues, in modulating neuronal migration is less(More)