139 research outputs found
Radio measurements for determining the energy scale of cosmic rays
This work is about Tunka-Rex, a radio detector for air showers in Siberia. After calibrating the detector and developing a reconstruction method for air shower events, three results are presented, obtained from the 2012-2014 data of Tunka-Rex:
- a method for measuring the energy with a single antenna station.
- a validation of the CoREAS code for simulation of radio emission.
- a comparison of dofferent experiments\u27s energy scales via the radio signal
Complying with Data Handling Requirements in Cloud Storage Systems
In past years, cloud storage systems saw an enormous rise in usage. However,
despite their popularity and importance as underlying infrastructure for more
complex cloud services, today's cloud storage systems do not account for
compliance with regulatory, organizational, or contractual data handling
requirements by design. Since legislation increasingly responds to rising data
protection and privacy concerns, complying with data handling requirements
becomes a crucial property for cloud storage systems. We present PRADA, a
practical approach to account for compliance with data handling requirements in
key-value based cloud storage systems. To achieve this goal, PRADA introduces a
transparent data handling layer, which empowers clients to request specific
data handling requirements and enables operators of cloud storage systems to
comply with them. We implement PRADA on top of the distributed database
Cassandra and show in our evaluation that complying with data handling
requirements in cloud storage systems is practical in real-world cloud
deployments as used for microblogging, data sharing in the Internet of Things,
and distributed email storage.Comment: 14 pages, 11 figures; revised manuscript, accepted for publication in
IEEE Transactions on Cloud Computin
Формування конкурентних переваг підприємства в умовах зовнішньоекономічної діяльності
Abstract Background Whole genome sequencing has become fast, accurate, and cheap, paving the way towards the large-scale collection and processing of human genome data. Unfortunately, this dawning genome era does not only promise tremendous advances in biomedical research but also causes unprecedented privacy risks for the many. Handling storage and processing of large genome datasets through cloud services greatly aggravates these concerns. Current research efforts thus investigate the use of strong cryptographic methods and protocols to implement privacy-preserving genomic computations. Methods We propose Fhe-Bloom and Phe-Bloom, two efficient approaches for genetic disease testing using homomorphically encrypted Bloom filters. Both approaches allow the data owner to securely outsource storage and computation to an untrusted cloud. Fhe-Bloom is fully secure in the semi-honest model while Phe-Bloom slightly relaxes security guarantees in a trade-off for highly improved performance. Results We implement and evaluate both approaches on a large dataset of up to 50 patient genomes each with up to 1000000 variations (single nucleotide polymorphisms). For both implementations, overheads scale linearly in the number of patients and variations, while Phe-Bloom is faster by at least three orders of magnitude. For example, testing disease susceptibility of 50 patients with 100000 variations requires only a total of 308.31 s (σ=8.73 s) with our first approach and a mere 0.07 s (σ=0.00 s) with the second. We additionally discuss security guarantees of both approaches and their limitations as well as possible extensions towards more complex query types, e.g., fuzzy or range queries. Conclusions Both approaches handle practical problem sizes efficiently and are easily parallelized to scale with the elastic resources available in the cloud. The fully homomorphic scheme, Fhe-Bloom, realizes a comprehensive outsourcing to the cloud, while the partially homomorphic scheme, Phe-Bloom, trades a slight relaxation of security guarantees against performance improvements by at least three orders of magnitude
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BLOOM: BLoom filter based oblivious outsourced matchings
Whole genome sequencing has become fast, accurate, and cheap, paving the way towards the large-scale collection and processing of human genome data. Unfortunately, this dawning genome era does not only promise tremendous advances in biomedical research but also causes unprecedented privacy risks for the many. Handling storage and processing of large genome datasets through cloud services greatly aggravates these concerns. Current research efforts thus investigate the use of strong cryptographic methods and protocols to implement privacy-preserving genomic computations
Mutasynthetic Production and Antimicrobial Characterization of Darobactin Analogs
There is great need for therapeutics against multidrug-resistant, Gram-negative bacterial pathogens. Recently, darobactin A, a novel bicyclic heptapeptide that selectively kills Gram-negative bacteria by targeting the outer membrane protein BamA, was discovered. Its efficacy was proven in animal infection models of Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa, thus promoting darobactin A as a promising lead compound. Originally discovered from members of the nematode-symbiotic genus; Photorhabdus; , the biosynthetic gene cluster (BGC) encoding the synthesis of darobactin A can also be found in other members of the class; Gammaproteobacteria; . Therein, the precursor peptides DarB to -F, which differ in their core sequence from darobactin A, were identified; in silico; . Even though production of these analogs was not observed in the putative producer strains, we were able to generate them by mutasynthetic derivatization of a heterologous expression system. The analogs generated were isolated and tested for their bioactivity. The most potent compound, darobactin B, was used for cocrystallization with the target BamA, revealing a binding site identical to that of darobactin A. Despite its potency, darobactin B did not exhibit cytotoxicity, and it was slightly more active against Acinetobacter baumannii isolates than darobactin A. Furthermore, we evaluated the plasma protein binding of darobactin A and B, indicating their different pharmacokinetic properties. This is the first report on new members of this new antibiotic class, which is likely to expand to several promising therapeutic candidates.; IMPORTANCE; Therapeutic options to combat Gram-negative bacterial pathogens are dwindling with increasing antibiotic resistance. This study presents a proof of concept for the heterologous-expression approach to expand on the novel antibiotic class of darobactins and to generate analogs with different activities and pharmacokinetic properties. In combination with the structural data of the target BamA, this approach may contribute to structure-activity relationship (SAR) data to optimize inhibitors of this essential outer membrane protein of Gram-negative pathogens
Time-dependent CP Asymmetry in B->K* gamma as a (Quasi) Null Test of the Standard Model
We calculate the dominant Standard Model contributions to the time-dependent
CP asymmetry in B0->K*0 gamma, which is O(1/mb) in QCD factorisation. We find
that, including all relevant hadronic effects, in particular from soft gluons,
the asymmetry S is very small, S=-0.022\pm 0.015^{+0}_{-0.01}, and smaller than
suggested recently from dimensional arguments in a 1/mb expansion. Our result
implies that any significant deviation of the asymmetry from zero, and in
particular a confirmation of the current experimental central value,
S_{HFAG}=-0.28\pm 0.26, would constitute a clean signal for new physics.Comment: 14 pages, 1 figure, discussions on further power corrections adde
Bs to l+ l- gamma as a Test of Lepton Flavor Universality
We discuss a number of strategies to reduce the theoretical error, and make such a measurement a new
probe of the interactions that are interesting in the light of present-day
flavor discrepancies. In particular, for low di-lepton invariant mass we
propose to exploit the close parenthood between and the measured . For high , conversely, we exploit the fact that the decay is
dominated by two form-factor combinations, plus contributions from broad
charmonium that we model accordingly. We construct the ratio , akin
to and likewise sensitive to lepton-universality violation. Provided the
two rates in this ratio are integrated in a suitable region that minimises
bremsstrahlung contributions while maximising statistics, the ratio is very
close to unity and the form-factor dependence cancels to an extent that makes
it a new valuable probe of lepton-universality violating contributions in the
effective Hamiltonian. We finally speculate on additional ideas to extract
short-distance information from resonance regions, which are theoretically
interesting but statistically limited at present.Comment: 21 pages, 4 figures. v4: in appendix removed equation already present
in main tex
Projective center point and Tverberg theorems
We present projective versions of the center point theorem and Tverberg's
theorem, interpolating between the original and the so-called "dual" center
point and Tverberg theorems.
Furthermore we give a common generalization of these and many other known
(transversal, constraint, dual, and colorful) Tverberg type results in a single
theorem, as well as some essentially new results about partitioning measures in
projective space.Comment: 10 page
A randomized, double-blind, placebo-controlled clinical trial to evaluate the efficacy and safety of neramexane in patients with moderate to severe subjective tinnitus
<p>Abstract</p> <p>Background</p> <p>Neramexane is a new substance that exhibits antagonistic properties at α<sub>9</sub>α<sub>10 </sub>cholinergic nicotinic receptors and <it>N</it>-methyl-D-aspartate receptors, suggesting potential efficacy in the treatment of tinnitus.</p> <p>Methods</p> <p>A total of 431 outpatients with moderate to severe subjective tinnitus (onset 3-18 months before screening) were assigned randomly to receive either placebo or neramexane mesylate (25 mg/day, 50 mg/day and 75 mg/day) for 16 weeks, with assessment at 4-week intervals. The primary (intention-to-treat) efficacy analysis was based on the change from baseline in Week 16 in the total score of the adapted German short version of the validated Tinnitus Handicap Inventory questionnaire (THI-12).</p> <p>Results</p> <p>Compared with placebo, the largest improvement was achieved in the 50 mg/d neramexane group, followed by the 75 mg/d neramexane group. This treatment difference did not reach statistical significance at the pre-defined endpoint in Week 16 (<it>p </it>= 0.098 for 50 mg/d; <it>p </it>= 0.289 for 75 mg/d neramexane), but consistent numerical superiority of both neramexane groups compared with placebo was observed. Four weeks after the end of treatment, THI-12 scores in the 50 mg/d group were significantly better than those of the controls. Secondary efficacy variables supported this trend, with <it>p </it>values of < 0.05 for the 50 mg/d neramexane group associated with the functional-communicational subscores of the THI-12 and the assessments of tinnitus annoyance and tinnitus impact on life as measured on an 11-point Likert-like scale. No relevant changes were observed for puretone threshold, for tinnitus pitch and loudness match, or for minimum masking levels. The 25 mg/d neramexane group did not differ from placebo. Neramexane was generally well tolerated and had no relevant influence on laboratory values, electrocardiography and vital signs. Dizziness was the most common adverse event and showed a clear dose-dependence.</p> <p>Conclusions</p> <p>This study demonstrated the safety and tolerability of neramexane treatment in patients with moderate to severe tinnitus. The primary efficacy variable showed a trend towards improvement of tinnitus suffering in the medium- and high-dose neramexane groups. This finding is in line with consistent beneficial effects observed in secondary assessment variables. These results allow appropriate dose selection for further studies.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov NCT00405886</p
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