8,849 research outputs found
Local Nodes in Global Networks: The Geography of Knowledge Flows in Biotechnology Innovation
The literature on innovation and interactive learning has tended to emphasize the importance of local networks, inter-firm collaboration and knowledge flows as the principal source of technological dynamism. More recently, however, this view has come to be challenged by other perspectives that argue for the importance of non-local knowledge flows. According to this alternative approach, truly dynamic economic regions are characterized both by dense local social interaction and knowledge circulation, as well as strong inter-regional and international connections to outside knowledge sources and partners. This paper offers an empirical examination of these issues by examining the geography of knowledge flows associated with innovation in biotechnology. We begin by reviewing the growing literature on the nature and geography of innovation in biotechnology research and the commercialization process. Then, focusing on the Canadian biotech industry, we examine the determinants of innovation (measured through patenting activity), paying particular attention to internal resources and capabilities of the firm, as well as local and global flows of knowledge and capital. Our study is based on the analysis of Statistics Canadaâs 1999 Survey of Biotechnology Use and Development, which covers 358 core biotechnology firms. Our findings highlight the importance of in-house technological capability and absorptive capacity as determinants of successful innovation in biotechnology firms. Furthermore, our results document the precise ways in which knowledge circulates, in both embodied and disembodied forms, both locally and globally. We also highlight the role of formal intellectual property transactions (domestic and international) in promoting knowledge flows. Although we document the importance of global networks in our findings, our results also reveal the value of local networks and specific forms of embedding. Local relational linkages are especially important when raising capitalâand the expertise that comes with itâto support innovation. Nevertheless, our empirical results raise some troubling questions about the alleged pre-eminence of the local in fostering innovation
Ablation debris control by means of closed thick film filtered water immersion
The performance of laser ablation generated debris control by means of open immersion techniques have been shown to be limited by flow surface ripple effects on the beam and the action of ablation plume pressure loss by splashing of the immersion fluid. To eradicate these issues a closed technique has been developed which ensured a controlled geometry for both the optical interfaces of the flowing liquid film. This had the action of preventing splashing, ensuring repeatable machining conditions and allowed for control of liquid flow velocity. To investigate the performance benefits of this closed immersion technique bisphenol A polycarbonate samples have been machined using filtered water at a number of flow velocities. The results demonstrate the efficacy of the closed immersion technique: a 93% decrease in debris is produced when machining under closed filtered water immersion; the average debris particle size becomes larger, with an equal proportion of small and medium sized debris being produced when laser machining under closed flowing filtered water immersion; large debris is shown to be displaced further by a given flow velocity than smaller debris, showing that the action of flow turbulence in the duct has more impact on smaller debris. Low flow velocities were found to be less effective at controlling the positional trend of deposition of laser ablation generated debris than high flow velocities; but, use of excessive flow velocities resulted in turbulence motivated deposition. This work is of interest to the laser micromachining community and may aide in the manufacture of 2.5D laser etched patterns covering large area wafers and could be applied to a range of wavelengths and laser types
Engineered Spatial Inversion Symmetry Breaking In An Oxide Heterostructure Built From Isosymmetric Room-Temperature Magnetically Ordered Components
Cloning of the CYP51 gene from the eyespot pathogen Tapesia yallundae indicates that resistance to the DMI fungicide prochloraz is not related to sequence changes in the gene encoding the target site enzyme
The statistical mechanics of combinatorial optimization problems with site disorder
We study the statistical mechanics of a class of problems whose phase space
is the set of permutations of an ensemble of quenched random positions.
Specific examples analyzed are the finite temperature traveling salesman
problem on several different domains and various problems in one dimension such
as the so called descent problem. We first motivate our method by analyzing
these problems using the annealed approximation, then the limit of a large
number of points we develop a formalism to carry out the quenched calculation.
This formalism does not require the replica method and its predictions are
found to agree with Monte Carlo simulations. In addition our method reproduces
an exact mathematical result for the Maximum traveling salesman problem in two
dimensions and suggests its generalization to higher dimensions. The general
approach may provide an alternative method to study certain systems with
quenched disorder.Comment: 21 pages RevTex, 8 figure
Symmetry-preserving matchings
In the literature, the matchings between spacetimes have been most of the
times implicitly assumed to preserve some of the symmetries of the problem
involved. But no definition for this kind of matching was given until recently.
Loosely speaking, the matching hypersurface is restricted to be tangent to the
orbits of a desired local group of symmetries admitted at both sides of the
matching and thus admitted by the whole matched spacetime. This general
definition is shown to lead to conditions on the properties of the preserved
groups. First, the algebraic type of the preserved group must be kept at both
sides of the matching hypersurface. Secondly, the orthogonal transivity of
two-dimensional conformal (in particular isometry) groups is shown to be
preserved (in a way made precise below) on the matching hypersurface. This
result has in particular direct implications on the studies of axially
symmetric isolated bodies in equilibrium in General Relativity, by making up
the first condition that determines the suitability of convective interiors to
be matched to vacuum exteriors. The definition and most of the results
presented in this paper do not depend on the dimension of the manifolds
involved nor the signature of the metric, and their applicability to other
situations and other higher dimensional theories is manifest.Comment: LaTeX, 19 page
A microfluidic chip based model for the study of full thickness human intestinal tissue using dual flow
© 2016 Author(s). The study of inflammatory bowel disease, including Ulcerative Colitis and Crohn's Disease, has relied largely upon the use of animal or cell culture models; neither of which can represent all aspects of the human pathophysiology. Presented herein is a dual flow microfluidic device which holds full thickness human intestinal tissue in a known orientation. The luminal and serosal sides are independently perfused ex vivo with nutrients with simultaneous waste removal for up to 72 h. The microfluidic device maintains the viability and integrity of the tissue as demonstrated through Haematoxylin & Eosin staining, immunohistochemistry and release of lactate dehydrogenase. In addition, the inflammatory state remains in the tissue after perfusion on the device as determined by measuring calprotectin levels. It is anticipated that this human model will be extremely useful for studying the biology and tes ting novel interventions in diseased tissue
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