Shaping the formation of university-industry research collaborations: what type of proximity does really matter?

Research collaborations between universities and industry (U-I) are considered to be one important channel of potential localized knowledge spillovers (LKS). These collaborations favour both intended and unintended flows of knowledge and facilitate learning processes between partners from different organizations. Despite the copious literature on LKS, still little is known about the factors driving the formation of U-I research collaborations and, in particular, about the role that geographical proximity plays in the establishment of such relationships. Using collaborative research grants between universities and business firms awarded by the UK Engineering and Physical Sciences Research Council (EPSRC), in this article we disentangle some of the conditions under which different kinds of proximity contribute to the formation of U-I research collaborations, focusing in particular on clustering and technological complementarity among the firms participating in such partnerships

Ena/VASP function in retinal axons is required for terminal arborization but not pathway navigation

The Enabled/vasodilator-stimulated phosphoprotein (Ena/VASP) family of proteins is required for filopodia formation in growth cones and plays a crucial role in guidance cue-induced remodeling of the actin cytoskeleton. In vivo studies with pharmacological inhibitors of actin polymerization have previously provided evidence for the view that filopodia are needed for growth cone navigation in the developing visual pathway. Here we have re-examined this issue using an alternative strategy to generate growth cones without filopodia in vivo by artificially targeting Xena/XVASP (Xenopus homologs of Ena/VASP) proteins to mitochondria in retinal ganglion cells (RGCs). We used the specific binding of the EVH1 domain of the Ena/VASP family of proteins with the ligand motif FP4 to sequester the protein at the mitochondria surface. RGCs with reduced function of Xena/XVASP proteins extended fewer axons out of the eye and possessed dynamic lamellipodial growth cones missing filopodia that advanced slowly in the optic tract. Surprisingly, despite lacking filopodia, the axons navigated along the optic pathway without obvious guidance errors, indicating that the Xena/XVASP family of proteins and filopodial protrusions are non-essential for pathfinding in retinal axons. However, depletion of Xena/XVASP proteins severely impaired the ability of growth cones to form branches within the optic tectum, suggesting that this protein family, and probably filopodia, plays a key role in establishing terminal arborizations

Diagnosis and treatment of thoracic aortic intramural hematoma

AbstractPurpose: This report reviews our recent experience with nine patients who had intramural hematoma of the thoracic aorta.Methods: This was a retrospective study of all patients who had intramural hematoma at our institution from 1989 to 1994. Patients who had identifiable intimal flap, tear, or penetrating aortic ulcer were excluded from the study.Results: Among these nine elderly patients (mean age, 76 years), the most common presentation was chest or back pain. Intramural hematoma was diagnosed by a variety of high-resolution imaging techniques. The descending thoracic aorta alone was involved in seven patients, whereas the ascending aorta was affected in the other two patients. One patient had evidence of an aneurysm (5.0 cm diameter) in the region of the hematoma. All patients were initially managed nonsurgically with blood pressure control. Both patients who had ascending aortic involvement had progression of aortic hematoma, which resulted in death in one case and in successful surgery in the other. Six of the seven patients who had descending aortic involvement alone were successfully managed without aortic surgery. The patient who had intramural hematoma and associated aortic aneurysm, however, had severe, recurrent pain and underwent successful aortic replacement. Another patient had recurrent pain associated with hypertension, but was successfully managed nonsurgically with antihypertensive therapy. All eight survivors are doing well at a median follow-up of 19 months.Conclusions: Intramural hematoma appears to be a distinct entity, although overlap with aortic dissection or penetrating aortic ulcer exists. Aggressive control of blood pressure with intensive care unit monitoring has been our initial management. Patients who have involvement of the descending thoracic aorta alone can frequently be managed without surgery in the absence of coexisting aneurysmal dilatation or disease progression. Our experience suggests that a more aggressive approach with early surgery is warranted in patients who have ascending aortic involvement or those who have coexisting aneurysm and intramural hematoma. (J Vasc Surg 1996;24;1022-9.

Calculation of the positron bound state with the copper atom

A new relativistic method for calculation of positron binding to atoms is presented. The method combines a configuration interaction treatment of the valence electron and the positron with a many-body perturbation theory description of their interaction with the atomic core. We apply this method to positron binding by the copper atom and obtain the binding energy of 170 meV (+ - 10%). To check the accuracy of the method we use a similar approach to calculate the negative copper ion. The calculated electron affinity is 1.218 eV, in good agreement with the experimental value of 1.236 eV. The problem of convergence of positron-atom bound state calculations is investigated, and means to improve it are discussed. The relativistic character of the method and its satisfactory convergence make it a suitable tool for heavier atoms.Comment: 15 pages, 5 figures, RevTe

Positron and positronium affinities in the work-formalism Hartree-Fock approximation

Positron binding to anions is investigated within the work formalism proposed by Harbola and Sahni for the halide anions and the systems Li^- through O^- excluding Be^- and N^-. The toal ground-state energies of the anion-positron bound systems are empirically found to be an upper bound to the Hartree-Fock energies. The computed expectation values as well as positron and positronium affinities are in good agreement with their restricted Hartree-Fock counterparts. Binding of a positron to neutral species is also investigated using an iterative method.Comment: 12 pages, to appear in Physical Review

Communities and patterns of scientific collaboration in Business and Management

This is the author's accepted version of this article deposited at arXiv (arXiv:1006.1788v2 [physics.soc-ph]) and subsequently published in Scientometrics October 2011, Volume 89, Issue 1, pp 381-396. The final publication is available at link.springer.com http://link.springer.com/article/10.1007%2Fs11192-011-0439-1Author's note: 17 pages. To appear in special edition of Scientometrics. Abstract on arXiv meta-data a shorter version of abstract on actual paper (both in journal and arXiv full pape

Community structure and patterns of scientific collaboration in Business and Management

This is the author's accepted version of this article deposited at arXiv (arXiv:1006.1788v2 [physics.soc-ph]) and subsequently published in Scientometrics October 2011, Volume 89, Issue 1, pp 381-396. The final publication is available at link.springer.com http://link.springer.com/article/10.1007%2Fs11192-011-0439-1Author's note: 17 pages. To appear in special edition of Scientometrics. Abstract on arXiv meta-data a shorter version of abstract on actual paper (both in journal and arXiv full pape

Performance-based financing as a health system reform : mapping the key dimensions for monitoring and evaluation

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