3,972 research outputs found
Fostering University-Industry R&D Collaborations in European Union Countries
This paper advances our understanding of university-industry research and development (R&D) collaborations. These strategic relationships are a dimension of entrepreneurial activity, and they are thus important drivers of economic growth and development. Business collaboration with universities increases the efficiency and effectiveness of industrial investments. Previous studies have found that universities are more likely to collaborate with industry if the business is mature and large, is engaged in exploratory internal R&D, and there are not major intellectual property (IP) issues between both parties. Businesses gain from such collaborations through increased commercialisation probabilities and economies of technological scope. Based on publicly available data collected by the Science-to-Business Marketing Research Centre of Germany as part of a European Commission project, our paper focuses on two key questions. First, why are there cross-country differences in the extent to which universities collaborate with business in R&D? Second, are there covariates with these differences that might offer insight into policy prescriptions and policy levers for enhancing the extent to which such collaboration takes place? We find that access is positive and statistically significant in relation to fostering university-business R&D collaborations. Our results, albeit that they are tempered by a small sample of data, have implications how national innovation systems support further harmonization of IP regimes across universities and how universities prioritise their own investments and incentives
Cell Surface Labeling of Escherichia coli via Copper(I)-Catalyzed [3+2] Cycloaddition
Labeling of the cell surface of Escherichia coli was accomplished by expression of a recombinant outer membrane protein, OmpC, in the presence of the unnatural amino acid azidohomoalanine, which acts as a methionine surrogate. The surface-exposed azide moieties of whole cells were biotinylated via Cu(1)-catalyzed [3+2] azide-alkyne cycloaddition. The specificity of labeling of both wild-type OmpC and a mutant containing additional methionine sites for azidohomoalanine incorporation was confirmed by Western blotting. Flow cytometry was performed to examine the specificity of the labeling. Cells that express the mutant form of OmpC in the presence of azidohomoalanine, which were biotinylated and stained with fluorescent avidin, exhibit a mean fluorescence 10-fold higher than the background. Incorporation of an unnatural amino acid can thus be determined on a single-cell basis
Questioning the Logic of Broken Windows: Some People “See” More Local Incivilities than Others
Many attribute New York’s massive fall in crime that began in the early 1990s to the implementation of the “broken windows” policing policy that sought to reduce “incivilities” – the social and physical indicators of neighborhood deterioration. In new research, Nathan W. Link and James M. Kelly examine the common wisdom that urban incivility leads to fear of crime. They argue that some people can be more “tuned in” to incivilities in their environment than others, and that those who are more generally fearful perceive greater incivilities
A photonic crystal cavity-optical fiber tip nanoparticle sensor for biomedical applications
We present a sensor capable of detecting solution-based nanoparticles using
an optical fiber tip functionalized with a photonic crystal cavity. When sensor
tips are retracted from a nanoparticle solution after being submerged, we find
that a combination of convective fluid forces and optically-induced trapping
cause an aggregation of nanoparticles to form directly on cavity surfaces. A
simple readout of quantum dot photoluminescence coupled to the optical fiber
shows that nanoparticle presence and concentration can be detected through
modified cavity properties. Our sensor can detect both gold and iron oxide
nanoparticles and can be utilized for molecular sensing applications in
biomedicine.Comment: 13 pages, 5 figure
Medium-Energy Gamma-Ray Astrophysics with the 3-DTI Gamma-Ray Telescope
Gamma-ray observations in the medium energy range (0.50-50.0 MeV) are central to unfolding many outstanding questions in astrophysics. The challenges of medium-energy gamma-ray observations, however, are the low photon statistics and large backgrounds. We review these questions, address the telescope technology requirements, and describe our development of the 3-Dimensional Track Imaging (3-DTI) Compton telescope and its performance for a new mediumenergy gamma-ray mission. The 3-DTI is a large-volume time projection chamber (TPC) with a 2-dimensional gas micro-well detector (MWD) readout
Introduction of an Aliphatic Ketone into Recombinant Proteins in a Bacterial Strain that Overexpresses an Editing-Impaired Leucyl-tRNA Synthetase
Like leucine? A leucine analogue containing a ketone has been incorporated into proteins in E. coli. Only E. coli strains overexpressing an editing-deficient leucyl-tRNA synthetase were capable of synthesizing proteins with the aliphatic ketone amino acid. Modification of ketone-containing proteins under mild conditions has been demonstrated
Simulated Performance of 3-DTI Gamma-Ray Telescope Concepts
We present Monte Carlo simulations of two astronomical gamma-ray telescope concepts based on the ThreeDimensional Track Imager (3- DTI) detector. The 3-DTI consists of a time projection chamber with two-dimensional, crossedstrip micro-well detector readout. The full three- dimensional reconstruction of charged-particle tracks in the gas volume is obtained from transient digitizers, which record the time signature of the charge collected in the wells of each strip. Such detectors hold great promise for advanced Compton telescope (ACT) and advanced pair telescope (APT) concepts due to the very precise measurement of charged particle momenta that is possible (Compton recoil electrons and electron-positron pairs, respectively). We have investigated the performance of baseline ACT and APT designs based on the 3-DTI detector using simulation tools based on GEANT3 and GEANT4, respectively. We present the expected imaging, spectroscopy, polarimetry, and background performance of each design
Exploring Halo Substructure with Giant Stars IV: The Extended Structure of the Ursa Minor Dwarf Spheroidal
We present a large area photometric survey of the Ursa Minor dSph. We
identify UMi giant star candidates extending to ~3 deg from the center of the
dSph. Comparison to previous catalogues of stars within the tidal radius of UMi
suggests that our photometric luminosity classification is 100% accurate. Over
a large fraction of the survey area, blue horizontal branch stars associated
with UMi can also be identified. The spatial distribution of both the UMi giant
stars and the BHB stars are remarkably similar, and a large fraction of both
samples of stars are found outside the tidal radius of UMi. An isodensity
contour map of the stars within the tidal radius of UMi reveals two
morphological peculiarities: (1) The highest density of dSph stars is offset
from the center of symmetry of the outer isodensity contours. (2) The overall
shape of the outer contours appear S-shaped. We find that previously determined
King profiles with ~50' tidal radii do not fit well the distribution of our UMi
stars. A King profile with a larger tidal radius produces a reasonable fit,
however a power law with index -3 provides a better fit for radii > 20'. The
existence of UMi stars at large distances from the core of the galaxy, the
peculiar morphology of the dSph within its tidal radius, and the shape of its
surface density profile all suggest that UMi is evolving significantly due to
the tidal influence of the Milky Way. However, the photometric data on UMi
stars alone does not allow us to determine if the candidate extratidal stars
are now unbound or if they remain bound to the dSph within an extended dark
matter halo. (Abridged)Comment: accepted by AJ, 32 pages, 15 figures, emulateapj5 styl
Exploring Halo Substructure with Giant Stars. VI. Extended Distributions of Giant Stars Around the Carina Dwarf Spheroidal Galaxy -- How Reliable Are They?
The question of the existence of active tidal disruption around various dSph
galaxies remains controversial. That debate often centers on the nature (bound
vs. unbound) of extended populations of stars. However, the more fundamental
issue of the very existence of the extended populations is still contentious.
We present an evaluation of the debate centering on one particular dSph,
Carina, for which claims both for and against the existence of stars beyond the
King radius have been made. Our review includes an examination of all previous
studies bearing on the Carina radial profile and shows that the survey method
which achieves the highest detected dSph signal-to-background in the outer
parts of the galaxy is the Washington M, T2 + DDO51 (MTD) filter approach from
Paper II in this series. We then address statistical methods used to evaluate
the reliability of MTD surveys in the presence of photometric errors and for
which a new, a posteriori statistical analysis methodology is provided.
Finally, these statistical methods are tested by new spectroscopy of stars in
the MTD-selected Carina candidate sample. Of 74 candidate giants with follow-up
spectroscopy, the MTD technique identified 61 new Carina members, including 8
stars outside the King radius. From a sample of 29 stars not initially
identified as candidate Carina giants but that lie just outside of our
selection criteria, 12 have radial velocities consistent with membership,
including 5 extratidal stars. Carina is shown to have an extended population of
giant stars extending to a major axis radius of 40' (1.44x the nominal King
radius).Comment: 56 pages, 10 figures. Submitted to the Astronomical Journal, 2004 Sep
2
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