We investigate the evolution of a universe with a decaying cosmological term (vacuum energy) that is assumed to be a function of the scale factor. In this model, while the cosmological term increases to the early universe, the radiation energy density is lower than the model with the cosmological "constant". We find that the effects of the decaying cosmological term on the expansion rate at the...

Some recent analyses of language as a transmission medium have fruitfully applied information theory in various ways to sequences of words. In most cases, the information contained in a word is defined as a function of that word's local context (e.g., its probability conditioned on the preceding word). A central assumption in much of this work is the important role of context. For example, the ...

Evolution of conspicuous signals may be constrained if animal coloration has nonsignaling as well as signaling functions. In aposematic wood tiger moth (Parasemia plantaginis) larvae, the size of a warning signal (orange patch on black body) varies phenotypically and genetically. Although a large warning signal is favored as an antipredator defense, we hypothesized that thermoregulation may con...

Nutrient pollution presents a serious threat to biodiversity conservation. In terrestrial ecosystems, the deleterious effects of nitrogen pollution are increasingly understood and several mitigating environmental policies have been developed. Compared to nitrogen, the effects of increased phosphorus have received far less attention, although some studies have indicated that phosphorus pollution...

Adaptive radiation of a lineage into a range of organisms with different niches underpins the evolution of life's diversity. Although the role of the environment in shaping adaptive radiation is well established, theory predicts that the evolvability and niche of the founding ancestor are also of importance. Direct demonstration of a causal link requires resolving the independent effects of the...

In the Maximum cost m′-subgraph problem we are given an undirected simple graph G(V,E) with weights w(v) on the vertices. The goal is to select a set U ⊆ V so that the number of edges with at least one endpoint in U is at most m′ with maximum weight W ∗. In [11] a ratio 3 approximation is given for problem. We improve this result by giving a 2 + approximation for the problem, for every constant...

Scientific cognition is a hard-won achievement, both from a historical point of view and a developmental point of view. Here, I review seven facets of lay cognition that run counter to, and often impede, scientific cognition: incompatible folk theories, missing ontologies, tolerance for shallow explanations, tolerance for contradictory explanations, privileging explanation over empirical data, ...

The development and implementation of new materials and manufacturing processes for aerospace application is often hindered by the high cost and long time span associated with current qualification procedures. The data requirements necessary for material and process qualification are extensive and often require millions of dollars and multiple years to complete. Furthermore, these qualification...

Aims. We present the results of multi epochs imaging observations of the companion to the planetary host Gliese 86. Associated to radial velocity measurements, this study aimed at characterizing dynamically the orbital properties and the mass of this companion (here after Gliese 86 B), but also at investigating the possible history of this particular system. Methods. We used the adaptive optics...

Primary production must constrain the amount of fish and invertebrates available to expanding fisheries; however the degree of limitation has only been demonstrated at regional scales to date. Here we show that phytoplanktonic primary production, estimated from an ocean-colour satellite (SeaWiFS), is related to global fisheries catches at the scale of Large Marine Ecosystems, while accounting f...