Simplification of networks by conserving path diversity and minimisation of the search information.

Alternative paths in a network play an important role in its functionality as they can maintain the information flow under node/link failures. In this paper we explore the navigation of a network taking into account the alternative paths and in particular how can we describe this navigation in a concise way. Our approach is to simplify the network by aggregating into groups the nodes that do not contribute to alternative paths. We refer to these groups as super-nodes, and describe the post-aggregation network with super-nodes as the skeleton network. We present a method to describe with the least amount of information the paths in the super-nodes and skeleton network. Applying our method to several real networks we observed that there is scaling behaviour between the information required to describe all the paths in a network and the minimal information to describe the paths of its skeleton. We show how from this scaling we can evaluate the information of the paths for large networks with less computational cost

Likelihood-based approach to discriminate mixtures of network models that vary in time.

Discriminating between competing explanatory models as to which is more likely responsible for the growth of a network is a problem of fundamental importance for network science. The rules governing this growth are attributed to mechanisms such as preferential attachment and triangle closure, with a wealth of explanatory models based on these. These models are deliberately simple, commonly with the network growing according to a constant mechanism for its lifetime, to allow for analytical results. We use a likelihood-based framework on artificial data where the network model changes at a known point in time and demonstrate that we can recover the change point from analysis of the network. We then use real datasets and demonstrate how our framework can show the changing importance of network growth mechanisms over time

Using a Bayesian approach to reconstruct graph statistics after edge sampling

Often, due to prohibitively large size or to limits to data collecting APIs, it is not possible to work with a complete network dataset and sampling is required. A type of sampling which is consistent with Twitter API restrictions is uniform edge sampling. In this paper, we propose a methodology for the recovery of two fundamental network properties from an edge-sampled network: the degree distribution and the triangle count (we estimate the totals for the network and the counts associated with each edge). We use a Bayesian approach and show a range of methods for constructing a prior which does not require assumptions about the original network. Our approach is tested on two synthetic and three real datasets with diverse sizes, degree distributions, degree-degree correlations and triangle count distributions

Is the Rehbein procedure obsolete in the treatment of Hirschsprung’s disease?

Contains fulltext : 87916.pdf (publisher's version ) (Closed access)PURPOSE: After 25 years of practice and positive results of the Rehbein-procedure (RB) for children with Hirschsprung Disease (HD), we changed to the less invasive transanal endorectal pull through (TERPT). The aim of this study was to compare short- and mid-term complications of these two procedures in our patients with HD. METHODS: Retrospective data of 50 HD patients were analyzed. Of these patients, 25 underwent RB (2000-2006) and in 25 the TERPT was performed (2005-2009). Medical records were reviewed to score complications and outcomes. Differences were analyzed using Chi-Square and Mann-Whitney U tests. RESULTS: All RB patients (100%) were given a colostomy compared with four patients (16%) in the TERPT group (p < 0.001). The average age at surgery in the RB group was 191 days whereas this was 72 days in the TERPT group (p < 0.01). The mean length of time of surgery in the RB group (158 min) was not significantly different from that in the TERPT group (183 min). Ganglion cells were located in all specimens at the proximal end of the specimens. The median time to first feeding significantly decreased from 2 days (range 1-11) in the RB group to 1 day (range 1-3) in the TERPT group (p < 0.01). The median length of hospital stay decreased in the TERPT group (8 days) compared with the RB group (10 days) (p < 0.001). There was a significant reduction in postoperative obstructive symptoms during the first 6 months in the TERPT group (48%) compared with the RB group (84%) (p = 0.016). Postoperative enterocolitis decreased from 40% in the RB group to 24% in the TERPT group although this was not statistically significant. CONCLUSIONS: The introduction of TERPT reduced the need for colostomies; it shortened days to first feeding after surgery and reduced hospital stay. It also improved short-term outcome with less obstructive symptoms. We recommend TERPT surgery as a first choice in children with HD. we consider the RB now to be obsolete.1 november 201

Diversity in the Architecture of ATLs, a Family of Plant Ubiquitin-Ligases, Leads to Recognition and Targeting of Substrates in Different Cellular Environments

Ubiquitin-ligases or E3s are components of the ubiquitin proteasome system (UPS) that coordinate the transfer of ubiquitin to the target protein. A major class of ubiquitin-ligases consists of RING-finger domain proteins that include the substrate recognition sequences in the same polypeptide; these are known as single-subunit RING finger E3s. We are studying a particular family of RING finger E3s, named ATL, that contain a transmembrane domain and the RING-H2 finger domain; none of the member of the family contains any other previously described domain. Although the study of a few members in A. thaliana and O. sativa has been reported, the role of this family in the life cycle of a plant is still vague. To provide tools to advance on the functional analysis of this family we have undertaken a phylogenetic analysis of ATLs in twenty-four plant genomes. ATLs were found in all the 24 plant species analyzed, in numbers ranging from 20–28 in two basal species to 162 in soybean. Analysis of ATLs arrayed in tandem indicates that sets of genes are expanding in a species-specific manner. To get insights into the domain architecture of ATLs we generated 75 pHMM LOGOs from 1815 ATLs, and unraveled potential protein-protein interaction regions by means of yeast two-hybrid assays. Several ATLs were found to interact with DSK2a/ubiquilin through a region at the amino-terminal end, suggesting that this is a widespread interaction that may assist in the mode of action of ATLs; the region was traced to a distinct sequence LOGO. Our analysis provides significant observations on the evolution and expansion of the ATL family in addition to information on the domain structure of this class of ubiquitin-ligases that may be involved in plant adaptation to environmental stress

Auditory event-related potentials

Auditory event related potentials are electric potentials (AERP, AEP) and magnetic fields (AEF) generated by the synchronous activity of large neural populations in the brain, which are time-locked to some actual or expected sound event