Geographic constraints on social network groups

Social groups are fundamental building blocks of human societies. While our social interactions have always been constrained by geography, it has been impossible, due to practical difficulties, to evaluate the nature of this restriction on social group structure. We construct a social network of individuals whose most frequent geographical locations are also known. We also classify the individuals into groups according to a community detection algorithm. We study the variation of geographical span for social groups of varying sizes, and explore the relationship between topological positions and geographic positions of their members. We find that small social groups are geographically very tight, but become much more clumped when the group size exceeds about 30 members. Also, we find no correlation between the topological positions and geographic positions of individuals within network communities. These results suggest that spreading processes face distinct structural and spatial constraints.Comment: 10 pages, 5 figure

Netlang: A software for the linguistic analysis of corpora by means of complex networks

To date there is no software that directly connects the linguistic analysis of a conversation to a network program. Networks programs are able to extract statistical information from data basis with information about systems of interacting elements. Language has also been conceived and studied as a complex system. However, most proposals do not analyze language according to linguistic theory, but use instead computational systems that should save time at the price of leaving aside many crucial aspects for linguistic theory. Some approaches to network studies on language do apply precise linguistic analyses, made by a linguist. The problem until now has been the lack of interface between the analysis of a sentence and its integration into the network that could be managed by a linguist and that could save the analysis of any language. Previous works have used old software that was not created for these purposes and that often produced problems with some idiosyncrasies of the target language. The desired interface should be able to deal with the syntactic peculiarities of a particular language, the options of linguistic theory preferred by the user and the preservation of morpho-syntactic information (lexical categories and syntactic relations between items). Netlang is the first program able to do that. Recently, a new kind of linguistic analysis has been developed, which is able to extract a complexity pattern from the speaker's linguistic production which is depicted as a network where words are inside nodes, and these nodes connect each other by means of edges or links (the information inside the edge can be syntactic, semantic, etc.). The Netlang software has become the bridge between rough linguistic data and the network program. Netlang has integrated and improved the functions of programs used in the past, namely the DGA annotator and two scripts (ToXML.pl and Xml2Pairs.py) used for transforming and pruning data. Netlang allows the researcher to make accurate linguistic analysis by means of syntactic dependency relations between words, while tracking record of the nature of such syntactic relationships (subject, object, etc). The Netlang software is presented as a new tool that solve many problems detected in the past. The most important improvement is that Netlang integrates three past applications into one program, and is able to produce a series of file formats that can be read by a network program. Through the Netlang software, the linguistic network analysis based on syntactic analyses, characterized for its low cost and the completely non-invasive procedure aims to evolve into a sufficiently fine grained tool for clinical diagnosis in potential cases of language disorders

Mast Cells and Immunological Skin Diseases

Mast cells play an important role in both adaptive and innate immunity, and a large body of literature demonstrates their functions in skin immunity. This article reviews the literature on the role of this cell type in the pathogenesis of a number of immunological skin diseases, including contact dermatitis, atopic dermatitis, immunobullous disease, scleroderma, and chronic graft-vs.-host disease. In all these diseases, mast cells are noted to increase in number and undergo degranulation in the affected skin, and in some cases, their specific mediators are detected. Elucidation of the contribution of mast cells to the pathogenesis of these diseases has been aided significantly by the use of animal models, especially mouse models. The studies of mast cell-deficient mice in conjunction with normal congenic mice have been particularly fruitful, although in some cases, such as contact dermatitis, a definitive conclusion has not been achieved despite extensive efforts. The role of mast cells in atopic dermatitis has also been suggested by studies of gene polymorphism, which have linked some of the mast cell-related genes to the disease. In the case of scleroderma and chronic graft-vs.-host disease, the function of mast cells in fibrosis is further supported by the ability of these cells and their mediators to induce activation and proliferation of fibroblasts. Therapies targeting mast cells may prove beneficial for treatment of these inflammatory and autoimmune diseases