1,000 research outputs found
The spatial dimension of patenting by multinational firms in Europe
We investigate the spatial pattern of patenting by the world’s largest multinational enterprises (MNEs). Based on a summary of the theoretical literature on R&D by MNEs and the spatial nature of knowledge generation and knowledge spillovers, we expect spatial concentration of patenting by these large MNEs. A database is developed that provides information on patenting by European region (we use 125 regions) at the aggregated MNE group level. This database is used to describe a number of features of the spatial pattern of pateting by MNEs in Europe. The main findings in this respect are that MNEs patenting activities are strongly concentrated in a relatively small number of regions and that the share of foreign patenting in total patenting varies greatly by firm. In an attempt to shed light on the mechanisms behind these tendencies, we use patent citations to measure the spatial concentration of knowledge flows and spillovers between firms, and within the same firm between different regional locations. For the majority of cases, we find that units between which patent citations occur are located relatively near to each other, which indeed points to the spatial character of patent citations. This holds for between-firms citations and within-firms citations. Moreover, we find a distinct time pattern associated to knowledge flows (as indicated by patent citations): the spatial scope of these flows first broadens but then narrows down again
Guaranteeing correctness in privacy-friendly outsourcing by certificate validation
With computation power in the cloud becoming a commodity, it is more and more convenient to outsource computations to external computation parties. Assuring confidentiality, even of inputs by mutually distrusting inputters, is possible by distributing computations between different parties using multiparty computation. Unfortunately, this typically only guarantees correctness if a limited number of computation parties are malicious. If correctness is needed when all computation parties are malicious, then one currently needs either fully homomorphic encryption or ``universally verifiable'' multiparty computation; both are impractical for large computations. In this paper, we show for the first time how to achieve practical privacy-friendly outsourcing with correctness guarantees, by using normal multiparty techniques to compute the result of a computation, and then using slower verifiable techniques only to verify that this result was correct. We demonstrate the feasibility of our approach in a linear programming case study. Keywords: secret sharing , threshold cryptography, zero knowledg
Quantum secret sharing with qudit graph states
We present a unified formalism for threshold quantum secret sharing using
graph states of systems with prime dimension. We construct protocols for three
varieties of secret sharing: with classical and quantum secrets shared between
parties over both classical and quantum channels.Comment: 13 pages, 12 figures. v2: Corrected to reflect imperfections of (n,n)
QQ protocol. Also changed notation from to , corrected typos,
updated references, shortened introduction. v3: Updated acknowledgement
Securely computing a similarity measure
The present invention relates to a method and a system of securely computing a measure of similarity for at least two sets of data. A basic idea of the present invention is to securely compare two sets of encrypted data to determine whether the two sets of data resemble each other to a sufficient extent. If the measure of similarity complies with predetermined criteria, the two sets of data from which the encrypted sets of data originate are considered to be identical
Molecular spectrum of TSHβ subunit gene defects in central hypothyroidism in the UK and Ireland.
OBJECTIVE: Homozygous mutations in the TSH beta subunit gene (TSHB) result in severe, isolated, central congenital hypothyroidism (CCH). This entity evades diagnosis in TSH-based congenital hypothyroidism (CH) screening programmes in the UK and Ireland. Accordingly, genetic diagnosis, enabling ascertainment of affected relatives in families, is critical for prompt diagnosis and treatment of the disorder. DESIGN, PATIENTS AND MEASUREMENTS: Four cases of isolated TSH deficiency from three unrelated families in the UK and Ireland were investigated for mutations or deletions in TSHB. Haplotype analysis, to investigate a founder effect, was undertaken in cases with identical mutations (c.373delT). RESULTS: Two siblings in kindred 1 were homozygous for a previously described TSHB mutation (c.373delT). In kindreds 2 and 3, the affected individuals were compound heterozygous for TSHB c.373delT and either a 5·4-kB TSHB deletion (kindred 2, c.1-4389_417*195delinsCTCA) or a novel TSHB missense mutation (kindred 3, c.2T>C, p.Met1?). Neurodevelopmental retardation, following delayed diagnosis and treatment, was present in 3 cases. In contrast, the younger sibling in kindred 1 developed normally following genetic diagnosis and treatment from birth. CONCLUSIONS: This study, including the identification of a second, novel, TSHB deletion, expands the molecular spectrum of TSHB defects and suggests that allele loss may be a commoner basis for TSH deficiency than previously suspected. Delayed diagnosis and treatment of profound central hypothyroidism in such cases result in neurodevelopmental retardation. Inclusion of thyroxine (T4) plus thyroxine-binding globulin (TBG), or free thyroxine (FT4) in CH screening, together with genetic case ascertainment enabling earlier therapeutic intervention, could prevent such adverse sequelae.Wellcome Trust (Grant IDs: 100585/Z/12/Z, 095564/Z/11/Z), National Institute for Health Research Biomedical Research Centre CambridgeThis is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1111/cen.1314
The Ellipticity of the Disks of Spiral Galaxies
The disks of spiral galaxies are generally elliptical rather than circular.
The distribution of ellipticities can be fit with a log-normal distribution.
For a sample of 12,764 galaxies from the Sloan Digital Sky Survey Data Release
1 (SDSS DR1), the distribution of apparent axis ratios in the i band is best
fit by a log-normal distribution of intrinsic ellipticities with ln epsilon =
-1.85 +/- 0.89. For a sample of nearly face-on spiral galaxies, analyzed by
Andersen and Bershady using both photometric and spectroscopic data, the best
fitting distribution of ellipticities has ln epsilon = -2.29 +/- 1.04. Given
the small size of the Andersen-Bershady sample, the two distribution are not
necessarily inconsistent. If the ellipticity of the potential were equal to
that of the light distribution of the SDSS DR1 galaxies, it would produce 1.0
magnitudes of scatter in the Tully-Fisher relation, greater than is observed.
The Andersen-Bershady results, however, are consistent with a scatter as small
as 0.25 magnitudes in the Tully-Fisher relation.Comment: 19 pages, 5 figures; ApJ, accepte
Radio Spectra of Giant Radio Galaxies from RATAN-600 Data
Measurements of the flux densities of the extended components of seven giant
radio galaxies obtained using the RATAN-600 radio telescope at wavelengths of
6.25 and 13 cm ar e presented. The spectra of components of these radio
galaxies are constructed using these new RA TAN-600 data together with data
from the WENSS, NVSS, and GB6 surveys. The spectral indices in the stu died
frequency range are calculated, and the need for detailed estimates of the
integrated contributi on of such objects to the background emission is
demonstrated.Comment: 7 pages, 2 figures, 5 table
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