It has been proposed that human cooperation is unique among animals for its scale and complexity, its altruistic nature and its occurrence among large groups of individuals that are not closely related or are even strangers. One potential solution to this puzzle is that the unique aspects of human cooperation evolved as a result of high levels of lethal competition (i.e. warfare) between geneti...

Numerical differentiation of noisy measurement data represents a problem frequently encountered in the field of gait analysis. There are two major determinants of the quality in calculated derivatives, namely the quality of the measurement data and the quality of the used differentiation technique. The quality of the measurement data, with respect to the maximum precision that can be obtained i...

During development, cells transition from a pluripotent to a differentiated state, generating all the different types of cells in the body. Development is generally considered an irreversible process, meaning that a differentiated cell is thought to be unable to return to the pluripotent state. However, it is now possible to reprogrammature cells to pluripotency. It is generally thought that re...

The sensory epithelium of the mammalian cochlea is composed of a regular mosaic of sensory hair cells and nonsensory supporting cells. During development, differentiation occurs in a gradient that progresses along the axis of the cochlea from base to apex. To begin to identify some of the factors that regulate this developmental process, the potential roles of planar and vertical signals were e...

A dynamic model for cell differentiation, where cells with internal chemical reaction dynamics interact with each other and replicate was studied. It led to spontaneous differentiation of cells and determination, as discussed in the isologous diversification. The following features of the differentiation were obtained: (1) hierarchical differentiation from a 'stem' cell to other cell types, wit...

Naive CD4(+) cells differentiate into T helper (Th1, Th2, Th9, Th17) and regulatory T (Treg) cells to execute their immunologic function. Whereas TGF-β suppresses Th1 and Th2 cell differentiation, this cytokine promotes Th9, Th17 and Foxp3(+) regulatory T cells depending upon the presence of other cytokines. IL-6 promotes Th17, but suppresses regulatory T cell differentiation. Moreover, natural...

MicroRNA are important regulators of CD4 T cell differentiation, altering the balance between the immunogenic and tolerogenic pathways. Studies in mice with microRNA-deficient T cells have revealed defects in differentiation into the regulatory T cell lineage; however, the individual microRNA responsible have remained elusive. A recent paper in The EMBO Journal uses a systematic screen to find ...

We employ a vertical differentiation model to examine the potential bias in pricing-to-market results when using export unit values aggregating differentiated products. Our results show that: (i) false evidence of pricing-to-market is always found when using unit values, whether the law of one price holds or not; and (ii) the size of the bias increases with the level of product differentiation....

We model a supply chain consisting of a production facility, a distribution center and two differentiated markets. Demand information is used to mitigate the effects of uncertainty in the output markets. We study the firm’s operational performance under alternative business processes, comparing early and delayed product differentiation. The comparison yields the value of postponement. Our resul...

Yan is an ETS-domain transcription factor responsible for maintaining Drosophila eye cells in a multipotent state. Yan is at the core of a regulatory network that determines the time and place in which cells transit from multipotency to one of several differentiated lineages. Using a fluorescent reporter for Yan expression, we observed a biphasic distribution of Yan in multipotent cells, with a...