9,477 research outputs found
Harvesting Entities from the Web Using Unique Identifiers -- IBEX
In this paper we study the prevalence of unique entity identifiers on the
Web. These are, e.g., ISBNs (for books), GTINs (for commercial products), DOIs
(for documents), email addresses, and others. We show how these identifiers can
be harvested systematically from Web pages, and how they can be associated with
human-readable names for the entities at large scale.
Starting with a simple extraction of identifiers and names from Web pages, we
show how we can use the properties of unique identifiers to filter out noise
and clean up the extraction result on the entire corpus. The end result is a
database of millions of uniquely identified entities of different types, with
an accuracy of 73--96% and a very high coverage compared to existing knowledge
bases. We use this database to compute novel statistics on the presence of
products, people, and other entities on the Web.Comment: 30 pages, 5 figures, 9 tables. Complete technical report for A.
Talaika, J. A. Biega, A. Amarilli, and F. M. Suchanek. IBEX: Harvesting
Entities from the Web Using Unique Identifiers. WebDB workshop, 201
Modeling Quantum Optical Components, Pulses and Fiber Channels Using OMNeT++
Quantum Key Distribution (QKD) is an innovative technology which exploits the
laws of quantum mechanics to generate and distribute unconditionally secure
cryptographic keys. While QKD offers the promise of unconditionally secure key
distribution, real world systems are built from non-ideal components which
necessitates the need to model and understand the impact these non-idealities
have on system performance and security. OMNeT++ has been used as a basis to
develop a simulation framework to support this endeavor. This framework,
referred to as "qkdX" extends OMNeT++'s module and message abstractions to
efficiently model optical components, optical pulses, operating protocols and
processes. This paper presents the design of this framework including how
OMNeT++'s abstractions have been utilized to model quantum optical components,
optical pulses, fiber and free space channels. Furthermore, from our toolbox of
created components, we present various notional and real QKD systems, which
have been studied and analyzed.Comment: Published in: A. F\"orster, C. Minkenberg, G. R. Herrera, M. Kirsche
(Eds.), Proc. of the 2nd OMNeT++ Community Summit, IBM Research - Zurich,
Switzerland, September 3-4, 201
A second eigenvalue bound for the Dirichlet Schroedinger operator
Let be the th eigenvalue of the Schr\"odinger
operator with Dirichlet boundary conditions on a bounded domain and with the positive potential . Following the spirit of the
Payne-P\'olya-Weinberger conjecture and under some convexity assumptions on the
spherically rearranged potential , we prove that . Here denotes the ball, centered at the
origin, that satisfies the condition .
Further we prove under the same convexity assumptions on a spherically
symmetric potential , that decreases
when the radius of the ball increases.
We conclude with several results about the first two eigenvalues of the
Laplace operator with respect to a measure of Gaussian or inverted Gaussian
density
Optical imaging of resonant electrical carrier injection into individual quantum dots
We image the micro-electroluminescence (EL) spectra of self-assembled InAs
quantum dots (QDs) embedded in the intrinsic region of a GaAs p-i-n diode and
demonstrate optical detection of resonant carrier injection into a single QD.
Resonant tunneling of electrons and holes into the QDs at bias voltages below
the flat-band condition leads to sharp EL lines characteristic of individual
QDs, accompanied by a spatial fragmentation of the surface EL emission into
small and discrete light- emitting areas, each with its own spectral
fingerprint and Stark shift. We explain this behavior in terms of Coulomb
interaction effects and the selective excitation of a small number of QDs
within the ensemble due to preferential resonant tunneling paths for carriers.Comment: 4 page
Comparative imipenem treatment of Staphylococcus aureus endocarditis in the rat
The efficacy of imipenem alone or in association with gentamicin against Staphylococcus aureus experimental endocarditis was compared to the efficacy of cloxacillin alone or in association with gentamicin. Parenteral treatment was started 24 h after intravenous bacterial challenge of rats with catheter-induced aortic valve vegetations. The cloxacillin MIC and MBC for Staph. aureus were 0.125 and 32 mg/l and the imipenem MIC and MBC 0.008 and 8 mg/l, respectively. In-vitro killing curves showed a synergistic effect between cloxacillin and gentamicin, and an additive effect between imipenem and gentamicin. Only large doses of cloxacillin (400 mg/kg tid) (producing serum levels above those obtained after intravenous injection of 2 g in man) achieved results comparable to those of imipenem 80 mg/kg tid (producing serum levels similar to those obtained after an intravenous dose of 750 mg in man) in reducing the bacterial numbers in vegetations after 3 and 5 days of treatment. There was a significantly greater reduction of bacterial numbers in vegetations after treatment with the association of cloxacillin and gentamicin than with cloxacillin alone. In contrast, the addition of gentamicin to imipenem did not improve significantly the results of treatment with imipenem alone, but imipenem alone was as good as the combination cloxacillin and gentamicin after 5 days of treatment. We conclude that imipenem is a highly bactericidal drug in this animal model, worth considering for clinical trials in the treatment of Staph. aureus infection
Gene identification for the cblD defect of vitamin B12 metabolism
Background Vitamin B12 (cobalamin) is an essential cofactor in several metabolic pathways. Intracellular conversion of cobalamin to its two coenzymes, adenosylcobalamin in mitochondria and methylcobalamin in the cytoplasm, is necessary for the homeostasis of methylmalonic acid and homocysteine. Nine defects of intracellular cobalamin metabolism have been defined by means of somatic complementation analysis. One of these defects, the cblD defect, can cause isolated methylmalonic aciduria, isolated homocystinuria, or both. Affected persons present with multisystem clinical abnormalities, including developmental, hematologic, neurologic, and metabolic findings. The gene responsible for the cblD defect has not been identified.
Methods We studied seven patients with the cblD defect, and skin fibroblasts from each were investigated in cell culture. Microcell-mediated chromosome transfer and refined genetic mapping were used to localize the responsible gene. This gene was transfected into cblD fibroblasts to test for the rescue of adenosylcobalamin and methylcobalamin synthesis.
Results The cblD gene was localized to human chromosome 2q23.2, and a candidate gene, designated MMADHC (methylmalonic aciduria, cblD type, and homocystinuria), was identified in this region. Transfection of wild-type MMADHC rescued the cellular phenotype, and the functional importance of mutant alleles was shown by means of transfection with mutant constructs. The predicted MMADHC protein has sequence homology with a bacterial ATP-binding cassette transporter and contains a putative cobalamin binding motif and a putative mitochondrial targeting sequence.
Conclusions Mutations in a gene we designated MMADHC are responsible for the cblD defect in vitamin B12 metabolism. Various mutations are associated with each of the three biochemical phenotypes of the disorder
Controversies in the Use of Passive Immunotherapy for Bacterial Infections in the Critically Ill Patient
Several preparations of standard immunoglobulins for intravenous use have been tested as adjunctive therapy for bacterial infections in premature neonates and in critically ill adults after major surgery, trauma, and burn. The use of intravenous immunoglobulins in these settings is controversial because the efficacy and cost-effectiveness of this treatment are still not definitively established. Specific preparations of immunoglobulins against Pseudomonas aeruginosa for intramuscular administration have shown promising efficacy, and preparations for intravenous administration are now under investigation. Cross-protection against a wide range of gram-negative infections has been attempted by the administration of antiserum to the core glycolipid of lipopolysaccharide prepared from volunteers immunized with the J5 mutant of Escherichia coli 0111. Treatment with this preparation improved the survival rate of patients with gram-negative bacteremia and, when administered prophylactically to high-risk surgical patients, prevented shock and death related to gram-negative infections. The mechanism of protection of the J5 antiserum is not clearly understood because of our inability to measure the actual protective antibody in polyclonal J5 antiserum. Thus, the preparation of readily available cross-protective hyperimmune immunoglobulins is hampered because there is presently no method of selecting appropriate donors or high-titered plasma pool
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