acceptance model and the theory of planned behavior, the model of PC utilization, the innovation diffusion theory, and the social cognitive theory. Using data from four organizations over a six-month period with three points of measurement, the eight models explained between 17 percent and 53 percent

and reconstruction based on spline kernels. The key in all constructions is to identify the innovative part of a signal (e.g., time instants and weights of Diracs) using an annihilating or locator filter: a device well known in spectral analysis and error-correction coding. This leads to standard computational

The processes responsible for the evolution of key innovations, whereby lineages acquire qualitatively new functions that expand their ecological opportunities, remain poorly understood. We examined how a virus, bacteriophage l, evolved to infect its host, Escherichia coli, through a novel pathway

review principles that show promise for allowing engineers to enhance human---computer interaction through an elegant coupling of automated services with direct manipulation. Key ideas will be highlighted in terms of the LookOut system for scheduling and meeting management. Keywords Intelligent agents

statistical power, tests of symmetry. The effect of key innovations (e.g., phytophagy in insects, Mitter et al. 1988; viviparity in fishes, Slowinski and Guyer 1993) on speciation rates has been a major focus of evolutionary biology in recent years (Sanderson and Donoghue 1996). Much

Since benchmarks drive computer science research and industry product development, which ones we use and how we evaluate them are key questions for the community. Despite complex runtime tradeoffs due to dynamic compilation and garbage collection required for Java programs, many evaluations still

with formally demonstrable convergence properties. Abstract-Integer programming has benefited from many innovations in models and methods. Some of the promising directions for elaborating these innovations in the future may be viewed from a framework that links the perspectives of artificial intelligence

at intermediate (proxy) nodes. Rather, it fully complies with the end-to-end TCP design principle. The key innovative idea is to continuously measure at the TCP source the rate of the connection by monitoring the

A number of methods have been developed to infer differential rates of species diversification through time and among clades using time-calibrated phylogenetic trees. However, we lack a general framework that can delineate and quantify heterogeneous mixtures of dynamic processes within single phylogenies. I developed a method that can identify arbitrary numbers of time-varying diversification processes on phylogenies without specifying their locations in advance. The method uses reversible-jump Markov Chain Monte Carlo to move between model subspaces that vary in the number of distinct diversification regimes. The model assumes that changes in evolutionary regimes occur across the branches of phylogenetic trees under a compound Poisson process and explicitly accounts for rate variation through time and among lineages. Using simulated datasets, I demonstrate that the method can be used to quantify complex mixtures of time-dependent, diversity-dependent, and constant-rate diversification processes. I compared the performance of the method to the MEDUSA model of rate variation among lineages. As an empirical example, I analyzed the history of speciation and extinction during the radiation of modern whales. The method described here will greatly facilitate the exploration of macroevolutionary dynamics across large phylogenetic trees, which may have been shaped by heterogeneous mixtures of distinct evolutionary processes.

The mouse Xin repeat-containing proteins (mXina and mXinb) localize to the intercalated disc in the heart. mXina is able to bundle actin filaments and to interact with b-catenin, suggesting a role in linking the actin cytoskeleton to N-cadherin/bcatenin adhesion. mXina-null mouse hearts display progressively ultrastructural alterations at the intercalated discs, and develop cardiac hypertrophy and cardiomyopathy with conduction defects. The up-regulation of mXinb in mXina-deficient mice suggests a partial compensation for the loss of mXina. To elucidate the evolutionary relationship between these proteins and to identify the origin of Xin, a phylogenetic analysis was done with 40 vertebrate Xins. Our results show that the ancestral Xin originated prior to the emergence of lamprey and subsequently underwent gene duplication early in the vertebrate lineage. A subsequent teleost-specific genome duplication resulted in most teleosts encoding at least three genes. All Xins contain a highly conserved b-catenin-binding domain within the Xin repeat region. Similar to mouse Xins, chicken, frog and zebrafish Xins also co-localized with b-catenin to structures that appear to be the intercalated disc. A putative DNA-binding domain in the N-terminus of all Xins is strongly conserved, whereas the previously characterized Mena/VASP-binding domain is a derived trait found only in Xinas from placental mammals. In the C-terminus, Xinas and Xinbs are more divergent relative to each other but each isoform from mammals shows a high degree of within-isoform sequence identity. This suggests different but conserved functions for mammalian Xina and Xinb. Interestingly, the origin of