Many phylogenetic comparative methods that are currently widely used in the scientific literature assume a Brownian motion model for trait evolution, but the suitability of that model is rarely tested, and a number of important factors might affect whether this model is appropriate or not. For instance, we might expect evolutionary change in adaptive radiations to be driven by the availability ...

The Arctic is the endpoint of many climatic gradients and is presently occupied by c. 2200 vascular plant species. Glaciation started in the Middle Eocene but a significant expansion of the Greenland ice shield occurred only c. 3.2 million yr ago, leading to the expansion of the treeless circumpolar arctic tundra. Available molecular phylogenetic studies were evaluated for 148 of 374 genera occ...

Many types of invisible electromagnetic waves are produced in our atmosphere. When these radiations penetrate our body, electric fields are induced inside the body, resulting in the absorption of power, which is different for different body parts and also depends on the frequency of radiations. Higher power absorption may result into health problems. In this communication, effects of electromag...

Diversity is a fundamental, yet threatened, property of ecological systems. The idea that diversity can itself favour diversification, in an autocatalytic process, is very appealing but remains controversial. Here, we study a generalized model of ecological communities and investigate how the level of initial diversity influences the possibility of evolutionary diversification. We show that eve...

New measurements of galaxy clustering and background radiations can provide improved constraints on the isotropy and homogeneity of the Universe on scales larger than 100 h Mpc. In particular, the angular distribution of radio sources and the X-Ray Background probe density fluctuations on scales intermediate between those explored by galaxy surveys and Cosmic Microwave Background experiments. O...

In multiple sclerosis, microstructural damage of normal-appearing brain tissue is an important feature of its pathology. Understanding these mechanisms is vital to help develop neuroprotective strategies. The visual pathway is a key model to study mechanisms of damage and recovery in demyelination. Anterograde trans-synaptic degeneration across the lateral geniculate nuclei has been suggested a...

INCE 1927 numerous investigators have subjected various plants and animals to radiations of different ion density to determine the relative biological effectiveness (RBE) of the different radiations. Usually it was found that the RBE increased as the linear energy transfer (LET-energy in electron volts dissipated per micron of tissue traversed by ionizing particles) or ion density of the radiat...