Puzzling the pieces

Lck activation: puzzling the pieces together

T cells are central players in the immune defense, but if deregulated they may also mediate the development of pathological conditions and diseases. Therefore, how T-cell functions are regulated is the focus of intense research since many years. Important steps forward in our understanding of the molecular mechanisms underlying T-cell biology have been made recently. These advances have allowed...

Puzzling About Partial Glucagon Responses to Hypoglycemia in Intrahepatic Islet Recipients: Missing Pieces

Fifteen years ago, Shapiro et al. (1), at the University of Alberta in Edmonton, Canada, published an article in the New England Journal of Medicine that caused great excitement. They reported that seven consecutive recipients with type 1 diabetes who had received intrahepatic infusions of human islet allografts maintained normal levels of HbA1c for more than 1 year after transplant (4.4–14.9 m...

Puzzling Permutations

We show how to describe and analyse multistage interconnection networks in a relational framework. We give simple elegant descriptions of butterfly networks, using only two functions for building networks from smaller networks. By studying the algebra of these functions, we can give a clear account of the properties of networks, without resorting to the standard methods of reasoning in terms of...

Pulling the Pieces Together:

The puzzling MILAGRO hot spots

We discuss the reported detection by the MILAGRO experiment of localised hot spots in the cosmic ray arrival distribution and the difficulty of interpreting these observations. A model based on secondary neutron production in the heliotail is shown to fail. An alternative model based on loss-cone leakage through a magnetic trap from a local source region is proposed.