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Biomedical subjects

A Grabowski

Publications and source records attributed to A Grabowski.

14 recordsLinked to original sources

Evolution of a social network: the role of cultural diversity.

We present a simple deterministic and based on local rules model of evolving social network, which leads to a network with the properties of a real social system, e.g., small-world topology and assortative mixing. The state of an individual Si is characterized by the values of Q cultural features, drawn from Gaussian distribution with variance sigma. The other control parameter is sociability Ti, which describes the maximal number of connections of an individual. The state of individuals and connections between them evolve in time. As results from numerical computations, an initial diversity of cultural features in a community has an essential influence on an evolution of social network. It was found that for a critical value of control parameter sigma c(Q) there is a structural transition and a hierarchical network with small-world topology of connections and a high clustering coefficient emerges. The emergence of small-world properties can be related to the creation of subculture groups in a community. The power-law relation between the clustering coefficient of a node and its connectivity C(k) approximately k-beta was observed in the case of a scale-free distribution of sociability Ti and a high enough cultural diversity in a population.

Journal Article↗

[Bilateral cervical arterial dissection as a sign of proximal aortic dissection: a rare cause of recidivating TIA].

Proximal aortic dissection is a life-threatening disease. In addition to other complications, involvement of the brain-supplying arteries can lead to acute cerebral ischemia. In the presented case, only the patient's clinical course and duplex sonography, which showed bilateral cervical arterial dissections, led to the diagnosis of aortic dissection. This case emphasizes that early ultrasound examination is crucial in patients with suspected cerebral ischemia.

Aortic Dissection↗

Epidemic spreading in a hierarchical social network.

A model of epidemic spreading in a population with a hierarchical structure of interpersonal interactions is described and investigated numerically. The structure of interpersonal connections is based on a scale-free network. Spatial localization of individuals belonging to different social groups, and the mobility of a contemporary community, as well as the effectiveness of different interpersonal interactions, are taken into account. Typical relations characterizing the spreading process, like a range of epidemic and epidemic curves, are discussed. The influence of preventive vaccinations on the spreading process is investigated. The critical value of preventively vaccinated individuals that is sufficient for the suppression of an epidemic is calculated. Our results are compared with solutions of the master equation for the spreading process and good agreement of the character of this process is found.

Animals↗