Age-dependent differences in human brain activity using a face- and location-matching task: An fMRI study

Purpose: To evaluate the differences of cortical activation patterns in young and elderly healthy subjects for object and spatial visual processing using a face- and location-matching task. Materials and Methods: We performed a face- and a location-matching task in 15 young (mean age: 28 +/- 9 years) and 19 elderly (mean age: 71 +/- 6 years) subjects. Each experiment consisted of 7 blocks alternating between activation and control condition. For face matching, the subjects had to indicate whether two displayed faces were identical or different. For location matching, the subjects had to press a button whenever two objects had an identical position. For control condition, we used a perception task with abstract images. Functional imaging was performed on a 1.5-tesla scanner using an EPI sequence. Results: In the face-matching task, the young subjects showed bilateral (right 1 left) activation in the occipito-temporal pathway (occipital gyrus, inferior and middle temporal gyrus). Predominantly right hemispheric activations were found in the fusiform gyrus, the right dorsolateral prefrontal cortex (inferior and middle frontal gyrus) and the superior parietal gyrus. In the elderly subjects, the activated areas in the right fronto-lateral cortex increased. An additional activated area could be found in the medial frontal gyrus (right > left). In the location-matching task, young subjects presented increased bilateral (right > left) activation in the superior parietal lobe and precuneus compared with face matching. The activations in the occipito-temporal pathway, in the right fronto-lateral cortex and the fusiform gyrus were similar to the activations found in the face-matching task. In the elderly subjects, we detected similar activation patterns compared to the young subjects with additional activations in the medial frontal gyrus. Conclusion: Activation patterns for object-based and spatial visual processing were established in the young and elderly healthy subjects. Differences between the elderly and young subjects could be evaluated, especially by using a face-matching task. Copyright (c) 2007 S. Karger AG, Basel

Noncompaction of the Ventricular Myocardium Is Associated with a De Novo Mutation in the β-Myosin Heavy Chain Gene

Noncompaction of the ventricular myocardium (NVM) is the morphological hallmark of a rare familial or sporadic unclassified heart disease of heterogeneous origin. NVM results presumably from a congenital developmental error and has been traced back to single point mutations in various genes. The objective of this study was to determine the underlying genetic defect in a large German family suffering from NVM. Twenty four family members were clinically assessed using advanced imaging techniques. For molecular characterization, a genome-wide linkage analysis was undertaken and the disease locus was mapped to chromosome 14ptel-14q12. Subsequently, two genes of the disease interval, MYH6 and MYH7 (encoding the α- and β-myosin heavy chain, respectively) were sequenced, leading to the identification of a previously unknown de novo missense mutation, c.842G>C, in the gene MYH7. The mutation affects a highly conserved amino acid in the myosin subfragment-1 (R281T). In silico simulations suggest that the mutation R281T prevents the formation of a salt bridge between residues R281 and D325, thereby destabilizing the myosin head. The mutation was exclusively present in morphologically affected family members. A few members of the family displayed NVM in combination with other heart defects, such as dislocation of the tricuspid valve (Ebstein's anomaly, EA) and atrial septal defect (ASD). A high degree of clinical variability was observed, ranging from the absence of symptoms in childhood to cardiac death in the third decade of life. The data presented in this report provide first evidence that a mutation in a sarcomeric protein can cause noncompaction of the ventricular myocardium

Current status of the multinational Arabidopsis community

The multinational Arabidopsis research community is highly collaborative and over the past thirty years these activities have been documented by the Multinational Arabidopsis Steering Committee (MASC). Here, we (a) highlight recent research advances made with the reference plant Arabidopsis thaliana; (b) provide summaries from recent reports submitted by MASC subcommittees, projects and resources associated with MASC and from MASC country representatives; and (c) initiate a call for ideas and foci for the “fourth decadal roadmap,” which will advise and coordinate the global activities of the Arabidopsis research community

Flexible and reconfigurable support for fault-tolerant object replication

Using object-based middleware infrastructures is popular for the development of services in distributed systems. Active object replication is a suitable strategy to increase the availability of such services. Existing replication architectures, however, show some deficiencies in their flexibility and reconfigurability. This thesis presents the FTflex architecture, which extends the CORBA-based Aspectix middleware with flexible and reconfigurable replication mechanisms. The contributions of this thesis support the development of replicated objects, enable a deterministic execution of object methods with multiple threads, and provide a flexible and dynamically reconfigurable group communication system. First of all, this thesis designs an efficient replication architecture on the basis of fragmented objects. The presented solution offers transparency for clients and allows the relocation of parts of the service functionality to the client side. The developer of a replicated object can use semantic annotations to optimize the replication strategies. A tool for automated code generation simplifies application development. Second, this thesis addresses the concurrent execution of object methods. The FTflex architecture provides new strategies that ensure determinism even if multiple threads want to access the shared object state concurrently. FTflex uses source code analysis and transformation as a novel way to influence the thread coordination in the replica code. The third contribution of this thesis is a reconfigurable, consensus-based group communication system, which is used as a basis for active replication. This system supports variable failure models, ranging from crash-stop to Byzantine. A significant advantage of the system is its transparent support for consistent reconfigurations at runtime. In addition, the system offers internal instrumentation as a basis for autonomous adaptation and self-optimization

Towards intrusion-resilient security monitoring in multi-cloud infrastructures

Multi-cloud architectures enable the design of resilient distributed Service applications. Such applications can benefit from a combination of intrusion-tolerant replication across clouds with intrusion detection and analysis mechanisms. Such mechanisms enable the detection of attacks that affect multiple replicas and thus exceed the intrusion masking capability,and in addition support fast reaction and recovery from local intrusions. In this work-in-progress paper we present a security Analysis on which an Intrusion detection and analysis service can be based on. We sketch the architecture of such a cross-cloud intrusion detection architecture that combines a set of wellknown mechanisms. The goal of our approach is obtaining a resource-efficient Service with optimal resilience against malicious attacks