Dynamic Gene Expression in the Human Cerebral Cortex Distinguishes Children from Adults

In comparison with other primate species, humans have an extended juvenile period during which the brain is more plastic. In the current study we sought to examine gene expression in the cerebral cortex during development in the context of this adaptive plasticity. We introduce an approach designed to discriminate genes with variable as opposed to uniform patterns of gene expression and found that greater inter-individual variance is observed among children than among adults. For the 337 transcripts that show this pattern, we found a significant overrepresentation of genes annotated to the immune system process (pFDR≅0). Moreover, genes known to be important in neuronal function, such as brain-derived neurotrophic factor (BDNF), are included among the genes more variably expressed in childhood. We propose that the developmental period of heightened childhood neuronal plasticity is characterized by more dynamic patterns of gene expression in the cerebral cortex compared to adulthood when the brain is less plastic. That an overabundance of these genes are annotated to the immune system suggests that the functions of these genes can be thought of not only in the context of antigen processing and presentation, but also in the context of nervous system development

Retrieving Complex Objects with HySpirit

Traditional Information Retrieval (IR) considers documents as atomic units. In this paper, we show the retrieval of the components of the documents which satisfy best the information need. This finer granularity eases the browsing of the retrieval result. The approach supports multimedia and networked IR since multimedia documents are composed of other objects and networks combine several collections comprising the documents. We gain a unified view on networks, databases, and multimedia documents by considering them as complex objects --- retrieval among a heterogeneous document corpus can be modeled appropriately. We present a probabilistic retrieval function where the initial estimation of probabilistic parameters is based on the logical structure of documents and the retrieval process is described as probabilistic logical inference. Probabilistic parameters and the retrieval process are represented in probabilistic Datalog programs which are executed by HySpirit --- a system for pro..

Abstract Retrieval of Complex Objects Using a Four-Valued Logic

The aggregated structure of documents plays a key role in full-text, multimedia, and network Information Retrieval (IR). Considering aggregation provides new querying fa-cilities and improves retrieval effectiveness. We present a knowledge representation for IR purposes which pays spe-cial attention to this aggregated structure of objects. In ad-dition, further features of objects can be described. Thus, the structure of full-text documents, the heterogeneity and the spatial and temporal relationships of objects typical for multimedia IR, and meta information for network IR are representable within one integrated framework. The model we propose allows for querying on the con-tent of documents (objects) as well as on other features. The query result may contain objects having different types. Instead of retrieving only whole documents, the retrieval process determines the least aggregated entities that imply the query.

A Descriptive Approach to Classification

Abstract. Nowadays information systems are required to be more adaptable and flexible than before to deal with the rapidly increasing quantity of available data and changing information needs. Text Classification (TC) is a useful task that can help to solve different problems in different fields. This paper investigates the application of descriptive approaches for modelling classification. The main objectives are increasing abstraction and flexibility so that expert users are able to customise specific strategies for their needs. The contribution of this paper is two-fold. Firstly, it illustrates that the modelling of classifiers in a descriptive approach is possible and it leads to a close definition w.r.t. mathematical formulations. Moreover, the automatic translation from PDatalog to mathematical formulation is discussed. Secondly, quality and efficiency results prove the approach feasibility for real-scale collections.