The impact of university patenting on the technological specialization of European regions: a technology-level analysis

This study investigates the relationship between the entry of universities into a new technology field and the innovative activities of firms located in the same geographical area. We aim to assess the presence of a significant correlation between academic research and technological specialization. The empirical setting is based on a dataset of 846,440 patent families, the output of 256 European regions and 428 local universities. The results of the fixed-effect models indicate a robust and positive relationship between the technological entry of academic institutions and the specialization of the region in the same domain. Furthermore, the technological distance between the portfolio of inventions filed by universities and that of co-localized firms is negatively correlated with the subsequent specialization of the hosting region, and this relationship is amplified by the entry of local academies. Several robustness checks have been performed. In particular, the results are tested on sub-samples that distinguish technology fields with lower and higher complexity and geographical regions with lower and higher innovative performance. The technological entry of universities has an additional positive effect for the strong and leading innovators whereas no significant premium or penalty was found for high and low-tech areas. This suggests that the entry of academic institutions into new technology fields occurring in a highly developed innovation ecosystem is more conducive to subsequent industrial specialization thanks to existing collaborations and transmission channels

Quantum cascade photonic crystal surface emitting injection laser

A surface emitting quantum cascade injection laser is presented. Direct surface emission is obtained by using a 2D photonic-band-gap structure that simultaneously acts as a microcavity. The approach may allow miniaturization and on-chip-integration of the devices

Fabrication methods for a quantum cascade photonic crystal surface emitting laser

Conventional quantum cascade (QC) lasers are intrinsically edge-emitting devices with mode confinement achieved via a standard mesa stripe configuration. Surface emission in edge emitting QC lasers has therefore necessitated redirecting the waveguided laser emission using a second order grating. This paper describes the methods used to fabricate a 2D photonic crystal (PC) structure with or without a central defect superimposed on an electrically pumped QC laser structure with the goal of achieving direct surface emission. A successful systematic study of PC hole radius and spacing was performed using e-beam lithography. This PC method offers the promise of a number of interesting applications, including miniaturization and integration of QC lasers

Crestal or 1.5 Mm Subcrestal Positioning of Transmucosal Dental Implants with Cemented or Screw-retained Crowns in Posterior Jaws: 4-month Data from a Single Centre Randomised Controlled Trial

OBJECTIVES. To compare crestal versus 1.5 mm subcrestal positioning of single transmu-cosal dental implants and screw-retained versus cemented crowns. MATERIALS AND METHODS. One hundred and sixty partially edentulous patients requiring one single implant-supported crown in the premolar/molar area were randomly allocated to four arms: crestal positioning and screw-retained crown (Group 1, 40 patients); crestal positioning and cement-retained crown (Group 2, 40 patients); 1.5 mm subcrestal positioning and screw-retained crown (Group 3, 40 patients); or 1.5 mm subcrestal positioning and cement-retained crown (Group 4, 40 patients) by a single operator. After an unloaded healing period of 3 months, definitive metal-ceramic crowns were delivered, and patients were followed up to 4 months after loading. Outcome measures were: crown and implant failures, complications, aesthetics assessed using the pink aesthetic score (PES), peri-implant marginal bone level changes and patient satisfaction, all recorded, when possible, by blinded assessors. RESULTS. At four months post-loading, four patients dropped out (two from Group 1 and one each from Groups 2 and 3, respectively). Two implants each failed in Groups 2 and 4, but there were no statistically significant differences between groups (P = 1.000). Complications affected four patients from Group 1, one from Group 2, two from Group 3 and six from Group 4, but between-group differences were not statistically significant (P = 0.207). The mean pink aesthetic scores were 10.30 ± 2.13 (Group 1), 10.22 ± 2.76 (Group 2), 10.47 ± 2.96 (Group 3), and 10.51 ± 2.24 (Group 4), respectively, with no statistically significant differences between groups (P = 0.9541). Likewise, there were no statistically significant differences in peri-implant marginal bone loss at 4 months after loading between groups (P = 0.9011:-0.21 mm ± 0.28 for Group 1,-0.25 mm ± 0.27 for Group 2,-0.28 mm ± 0.57 for Group 3 and-0.24 mm ± 0.26 for Group 4). Furthermore, there were no differences in patient satisfaction in terms of either function (P = 0.400) or aesthetics (P = 1.000), and all patients would undergo the same intervention again. CONCLUSIONS. No appreciable statistical or clinical differences were found between cre-stal or 1.5 mm subcrestal placement of transmucosal implants in posterior jaws or between rehabilitation with screw-retained or cement-retained crowns. However, longer follow-ups are required in order to formulate reliable clinical recommendations. CONFLICT OF INTEREST STATEMENT. GlobalD (Brignais, France), the manufacturer of the implants used in this investigation, partially funded this trial and donated the implants and the prosthetic components. However, all data belongs to the authors and the sponsor by no means interfered with the conduct of the trial or the publication of its results

Entrepreneurship education: the effects of challenge-based learning on the entrepreneurial mindset of university students

The aim of this paper is to investigate the implications of Challenge-Based Learning programs on entrepreneurial skills, and on the mindset and intentions of university students, through a quantitative approach. Resorting to an original database, we analyzed the pre-and post-levels of entrepreneurial skills, mindset and intention of 127 students who attended a Challenge-Based Learning program. Results show a positive and significant effect of Challenge-Based Learning programs on the entrepreneurial mindset and skills—that is, financial literacy, creativity, and planning—of the students

Challenge-based learning as a practice for engineering education to develop students' entrepreneurial mindset

This paper aims to investigate the implications of Challenge Based Learning programs on entrepreneurial skills, mindset and intentions of university students using a quantitative approach. Using an original database, we analyzed pre and post levels of entrepreneurial skills, mindset and intention of 127 students who attended a Challenge Based Learning program. Results show a positive and significant effect of Challenge Based Learning programs on entrepreneurial mindset and skills – such as financial literacy, creativity and planning – of the students. Moreover, results show a positive but non-significative effect on entrepreneurial intention

Contraction of cross-linked actomyosin bundles

Cross-linked actomyosin bundles retract when severed in vivo by laser ablation, or when isolated from the cell and micromanipulated in vitro in the presence of ATP. We identify the time scale for contraction as a viscoelastic time tau, where the viscosity is due to (internal) protein friction. We obtain an estimate of the order of magnitude of the contraction time tau ~ 10-100 s, consistent with available experimental data for circumferential microfilament bundles and stress fibers. Our results are supported by an exactly solvable, hydrodynamic model of a retracting bundle as a cylinder of isotropic, active matter, from which the order of magnitude of the active stress is estimated.Comment: To be published in Physical Biolog

Far-infrared surface-plasmon quantum-cascade lasers at 21.5 mu m and 24 mu m wavelengths

Quantum-cascade lasers operating above 20 mum (at lambda similar to 21.5 mum and lambda similar to 24 mum) wavelength are reported. Pulsed operation was obtained up to 140 K and with a peak power of a few milliwatts at cryogenic temperatures. Laser action originates from interminiband transitions in "chirped" superlattice active regions. The waveguides are based on surface-plasmon modes confined at a metal-semiconductor interface. The wavelengths were chosen in order to avoid major phonon absorption bands, which are particularly strong at energies just above the reststrahlen band. We also report on a 21.5-mum-wavelength laser based on a two-sided interface-plasmon waveguide. (C) 2001 American Institute of Physics

Far-field engineering of metal -metal terahertz quantum cascade lasers with integrated horn antennas

The far-field of metal-metal terahertz quantum cascade lasers is greatly improved through integrated and stable planar horn antennas on top of the QCL ridge. The antenna structures introduce a gradual change in the high modal confinement of metal-metal waveguides and permit an improved far-field, showing a five times increase in the emitted output power. The two dimensional far-field patterns are measured at 77K and compared to electromagnetic simulations. The influence of parasitic high order transverse modes are restricted through the engineering of antenna structure (ridge and antenna width) to couple out the fundamental mode only