2,211 research outputs found

    Knowledge Flows through Informal Contacts in Industrial Clusters Myths or Realities?

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    The role of informal networks in the development of regional clusters has received a lot of attention in the literature recently. Informal contact between employees in different firms is argued to be one of the main carriers of knowledge between firms in a cluster. This paper empirically examines the role of informal contacts in a specific cluster. In a recent questionnaire, we ask a sample of engineers in a regional cluster of wireless communication firms in Northern Denmark, a series of questions on informal networks. We analyze whether the engineers actually acquire valuable knowledge through these networks. We find that the engineers do share even valuable knowledge with informal contacts. This shows that informal contacts are important channels of knowledge diffusion.Informal contacts, regional clusters, communication technology

    Entry by Spinoff in a High-tech Cluster

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    Recently empirical studies have focused on how capabilities of new entering firms are important for the evolution of industries over time. The performance of new entrants appears to be significantly influenced by their pre-entry background. The general impression of the literature is that firms founded by former employees of successful incumbents have shown larger propensities to survive than other categories of new entrants. In the present paper, we use this approach to study the emergence and growth over the past three decades of a wireless telecommunications cluster around Aalborg in North Jutland, Denmark (NorCOM). The aim is to analyse the dominating forces behind the growth of NorCOM using detailed information about the founding events and organizational background of the individual entrants in the cluster. We show that the technological successes of firms in the region have powered a spinoff process, which can account for the majority of the growth in number of firms and employment in the cluster.Clusters, Spinoffs, Evolution of Industries, Entrepreneurs

    Entrepreneurial Founder Effects in the Growth of Regional Clusters How Early Success is a Key Determinant

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    How can the growth of regional clusters be explained? This paper studies in great detail the growth of the wireless communication cluster in Northern Denmark. Unlike the dominant theories, we argue that initial success of the first firms are the main driving force behind the generation of new firms that eventually lead to the formation of clusters. The success of the first firms tends to generate spin-offs, which become successful themselves due to the background of the founders.Agglomeration, Clusters, Spin-offs, Knowledge Diffusion

    EEG source imaging assists decoding in a face recognition task

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    EEG based brain state decoding has numerous applications. State of the art decoding is based on processing of the multivariate sensor space signal, however evidence is mounting that EEG source reconstruction can assist decoding. EEG source imaging leads to high-dimensional representations and rather strong a priori information must be invoked. Recent work by Edelman et al. (2016) has demonstrated that introduction of a spatially focal source space representation can improve decoding of motor imagery. In this work we explore the generality of Edelman et al. hypothesis by considering decoding of face recognition. This task concerns the differentiation of brain responses to images of faces and scrambled faces and poses a rather difficult decoding problem at the single trial level. We implement the pipeline using spatially focused features and show that this approach is challenged and source imaging does not lead to an improved decoding. We design a distributed pipeline in which the classifier has access to brain wide features which in turn does lead to a 15% reduction in the error rate using source space features. Hence, our work presents supporting evidence for the hypothesis that source imaging improves decoding

    An Improved Algorithm for RNA Secondary Structure Prediction

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    Though not as abundant in known biological processes as proteins,RNA molecules serve as more than mere intermediaries betweenDNA and proteins, e.g. as catalytic molecules. Furthermore,RNA secondary structure prediction based on free energyrules for stacking and loop formation remains one of the few majorbreakthroughs in the field of structure prediction. We present anew method to evaluate all possible internal loops of size at mostk in an RNA sequence, s, in time O(k|s|^2); this is an improvementfrom the previously used method that uses time O(k^2|s|^2).For unlimited loop size this improves the overall complexity ofevaluating RNA secondary structures from O(|s|^4) to O(|s|^3) andthe method applies equally well to finding the optimal structureand calculating the equilibrium partition function. We use ourmethod to examine the soundness of setting k = 30, a commonlyused heuristic

    Dose–Sensitivity, Conserved Non-Coding Sequences, and Duplicate Gene Retention through Multiple Tetraploidies in the Grasses

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    Whole genome duplications, or tetraploidies, are an important source of increased gene content. Following whole genome duplication, duplicate copies of many genes are lost from the genome. This loss of genes is biased both in the classes of genes deleted and the subgenome from which they are lost. Many or all classes are genes preferentially retained as duplicate copies are engaged in dose sensitive protein–protein interactions, such that deletion of any one duplicate upsets the status quo of subunit concentrations, and presumably lowers fitness as a result. Transcription factors are also preferentially retained following every whole genome duplications studied. This has been explained as a consequence of protein–protein interactions, just as for other highly retained classes of genes. We show that the quantity of conserved noncoding sequences (CNSs) associated with genes predicts the likelihood of their retention as duplicate pairs following whole genome duplication. As many CNSs likely represent binding sites for transcriptional regulators, we propose that the likelihood of gene retention following tetraploidy may also be influenced by dose–sensitive protein–DNA interactions between the regulatory regions of CNS-rich genes – nicknamed bigfoot genes – and the proteins that bind to them. Using grass genomes, we show that differential loss of CNSs from one member of a pair following the pre-grass tetraploidy reduces its chance of retention in the subsequent maize lineage tetraploidy

    Automated Conserved Non-Coding Sequence (CNS) Discovery Reveals Differences in Gene Content and Promoter Evolution among Grasses

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    Conserved non-coding sequences (CNS) are islands of non-coding sequence that, like protein coding exons, show less divergence in sequence between related species than functionless DNA. Several CNSs have been demonstrated experimentally to function as cis-regulatory regions. However, the specific functions of most CNSs remain unknown. Previous searches for CNS in plants have either anchored on exons and only identified nearby sequences or required years of painstaking manual annotation. Here we present an open source tool that can accurately identify CNSs between any two related species with sequenced genomes, including both those immediately adjacent to exons and distal sequences separated by \u3e12 kb of non-coding sequence. We have used this tool to characterize new motifs, associate CNSs with additional functions, and identify previously undetected genes encoding RNA and protein in the genomes of five grass species. We provide a list of 15,363 orthologous CNSs conserved across all grasses tested. We were also able to identify regulatory sequences present in the common ancestor of grasses that have been lost in one or more extant grass lineages. Lists of orthologous gene pairs and associated CNSs are provided for reference inbred lines of arabidopsis, Japonica rice, foxtail millet, sorghum, brachypodium, and maize

    Evolution of Plant P-Type ATPases

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    Five organisms having completely sequenced genomes and belonging to all major branches of green plants (Viridiplantae) were analyzed with respect to their content of P-type ATPases encoding genes. These were the chlorophytes Ostreococcus tauri and Chlamydomonas reinhardtii, and the streptophytes Physcomitrella patens (a non-vascular moss), Selaginella moellendorffii (a primitive vascular plant), and Arabidopsis thaliana (a model flowering plant). Each organism contained sequences for all five subfamilies of P-type ATPases. Whereas Na+ and H+ pumps seem to mutually exclude each other in flowering plants and animals, they co-exist in chlorophytes, which show representatives for two kinds of Na+ pumps (P2C and P2D ATPases) as well as a primitive H+-ATPase. Both Na+ and H+ pumps also co-exist in the moss P. patens, which has a P2D Na+-ATPase. In contrast to the primitive H+-ATPases in chlorophytes and P. patens, the H+-ATPases from vascular plants all have a large C-terminal regulatory domain as well as a conserved Arg in transmembrane segment 5 that is predicted to function as part of a backflow protection mechanism. Together these features are predicted to enable H+ pumps in vascular plants to create large electrochemical gradients that can be modulated in response to diverse physiological cues. The complete inventory of P-type ATPases in the major branches of Viridiplantae is an important starting point for elucidating the evolution in plants of these important pumps
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