1,045 research outputs found
ALMA detects a radial disk wind in DG Tauri
Astronomy and Astrophysics Letters, in press, 8 pagesAims. We aim to use the high spatial resolution of the Atacama Large Millimeter/submillimeter Array (ALMA) to map the flow pattern of molecular gas near DG Tauri and its disk, a young stellar object driving a jet and a molecular outflow. Methods. We use observations from ALMA in the J = 2-1 transition of 12CO, 13CO, and C 18O to study the Keplerian disk of DG Tauri and outflows that may be related to the disk and the jet. Results. We find a new wind component flowing radially at a steep angle (≈ 25° from the vertical) above the disk with a velocity of ≈ 3.1 km s -1. It continues the trend of decreasing velocity for increasing distance from the jet axis ("onion-like velocity structure"). Conclusions. The new component is located close to the protostellar disk surface and may be related to photoevaporative winds.Peer reviewe
Final Results from phase II of the Mainz Neutrino Mass Search in Tritium Decay
The paper reports on the improved Mainz experiment on tritum
spectroscopy which yields a 10 times' higher signal to background ratio than
before. The main experimental effects and systematic uncertainties have been
investigated in side experiments and possible error sources have been
eliminated. Extensive data taking took place in the years 1997 to 2001. A
residual analysis of the data sets yields for the square of the electron
antineutrino mass the final result of eV/c. We derive an upper limit of
eV/c at 95% confidence level for the mass itself.Comment: 22 pages, 22 figures submitted to EPJ
Applications of Radio-Frequency Heating in Environmental Technology
AbstractDirect dielectric heating with radio-frequency (RF) electromagnetic fields is used to optimize a variety of processes in environmental technology, namely soil remediation by soil vapor extraction or biodegradation, adsorptive-catalytic off-gas treatment, thermal regeneration of drying agents in biogas or natural gas treatment and decontamination and/or drying of brickwork
Operator entanglement of two-qubit joint unitary operations revisited: Schmidt number approach
Operator entanglement of two-qubit joint unitary operations is revisited.
Schmidt number is an important attribute of a two-qubit unitary operation, and
may have connection with the entanglement measure of the unitary operator. We
found the entanglement measure of two-qubit unitary operators is classified by
the Schmidt number of the unitary operators. The exact relation between the
operator entanglement and the parameters of the unitary operator is clarified
too.Comment: To appear in the Brazilian Journal of Physic
Generalized quantum measurements. Part I: Information properties of soft quantum measurements
A special class of soft quantum measurements as a physical model of the fuzzy
measurements widely used in physics is introduced and its information
properties are studied in detail.Comment: 25 pages, 3 figures, 25 ref
Association of Fidaxomicin with C. difficile spores: Effects of Persistence on Subsequent Spore Recovery, Outgrowth and Toxin Production.
Background: We have previously shown that fidaxomicin instillation prevents spore recovery in an in-vitro gut model, whereas vancomycin does not. The reasons for this are unclear. Here, we have investigated persistence of fidaxomicin and vancomycin on C. difficile spores, and examined post-antibiotic exposure spore recovery, outgrowth and toxin production. Methods: Prevalent UK C. difficile ribotypes (n=10) were incubated with 200mg/L fidaxomicin, vancomycin or a non-antimicrobial containing control for 1 h in faecal filtrate or Phosphate Buffered Saline. Spores were washed three times with faecal filtrate or phosphate buffered saline, and residual spore-associated antimicrobial activity was determined by bioassay. For three ribotypes (027, 078, 015), antimicrobial-exposed, faecal filtrate-washed spores and controls were inoculated into broth. Viable vegetative and spore counts were enumerated on CCEYL agar. Percentage phase bright spores, phase dark spores and vegetative cells were enumerated by phase contrast microscopy at 0, 3, 6, 24 and 48 h post-inoculation. Toxin levels (24 and 48h) were determined by cell cytotoxicity assay. Results: Fidaxomicin, but not vancomycin persisted on spores of all ribotypes following washing in saline (mean=10.1mg/L; range= 4.0-14mg/L) and faecal filtrate (mean =17.4mg/L; 8.4-22.1mg/L). Outgrowth and proliferation rates of vancomycin-exposed spores were similar to controls, whereas fidaxomicin-exposed spores showed no vegetative cell growth after 24 and 48 h. At 48h, toxin levels averaged 3.7 and 3.3 relative units (RU) in control and vancomycin-exposed samples, respectively, but were undetectable in fidaxomicin-exposed samples. Conclusion: Fidaxomicin persists on C. difficile spores, whereas vancomycin does not. This persistence prevents subsequent growth and toxin production in vitro. This may have implications on spore viability, thereby impacting CDI recurrence and transmission rates
Quantum Communication
Quantum communication, and indeed quantum information in general, has changed
the way we think about quantum physics. In 1984 and 1991, the first protocol
for quantum cryptography and the first application of quantum non-locality,
respectively, attracted a diverse field of researchers in theoretical and
experimental physics, mathematics and computer science. Since then we have seen
a fundamental shift in how we understand information when it is encoded in
quantum systems. We review the current state of research and future directions
in this new field of science with special emphasis on quantum key distribution
and quantum networks.Comment: Submitted version, 8 pg (2 cols) 5 fig
Lymphocyte Subsets Show Different Response Patterns to In Vivo Bound Natalizumab—A Flow Cytometric Study on Patients with Multiple Sclerosis
Natalizumab is an effective monoclonal antibody therapy for the treatment of relapsing- remitting multiple sclerosis (RRMS) and interferes with immune cell migration into the central nervous system by blocking the α4 subunit of very-late activation antigen-4 (VLA-4). Although well tolerated and very effective, some patients still suffer from relapses in spite of natalizumab therapy or from unwanted side effects like progressive multifocal leukoencephalopathy (PML). In search of a routine-qualified biomarker on the effectiveness of natalizumab therapy we applied flow cytometry and analyzed natalizumab binding to α4 and α4 integrin surface levels on T-cells, B-cells, natural killer (NK) cells, and NKT cells from 26 RRMS patients under up to 72 weeks of therapy. Four-weekly infusions of natalizumab resulted in a significant and sustained increase of lymphocyte-bound natalizumab (p<0.001) which was paralleled by a significant decrease in detectability of the α4 integrin subunit on all lymphocyte subsets (p<0.001). We observed pronounced natalizumab accumulations on T and B cells at single measurements in all patients who reported clinical disease activity (n = 4). The natalizumab binding capacity of in vitro saturated lymphocytes collected during therapy was strongly diminished compared to treatment-naive cells indicating a therapy-induced reduction of α4. Summing up, this pilot study shows that flow cytometry is a useful method to monitor natalizumab binding to lymphocytes from RRMS patients under therapy. Investigating natalizumab binding provides an opportunity to evaluate the molecular level of effectiveness of natalizumab therapy in individual patients. In combination with natalizumab saturation experiments, it possibly even provides a means of studying the feasability of patient-tailored infusion intervals. A routine-qualified biomarker on the basis of individual natalizumab saturation on lymphocyte subsets might be an effective tool to improve treatment safety
Heisenberg's Uncertainty Relation and Bell Inequalities in High Energy Physics
An effective formalism is developed to handle decaying two-state systems.
Herewith, observables of such systems can be described by a single operator in
the Heisenberg picture. This allows for using the usual framework in quantum
information theory and, hence, to enlighten the quantum feature of such systems
compared to non-decaying systems. We apply it to systems in high energy
physics, i.e. to oscillating meson-antimeson systems. In particular, we discuss
the entropic Heisenberg uncertainty relation for observables measured at
different times at accelerator facilities including the effect of CP violation,
i.e. the imbalance of matter and antimatter. An operator-form of Bell
inequalities for systems in high energy physics is presented, i.e. a
Bell-witness operator, which allows for simple analysis of unstable systems.Comment: 17 page
Neutrinoless double-beta decay and seesaw mechanism
From the standard seesaw mechanism of neutrino mass generation, which is
based on the assumption that the lepton number is violated at a large
(~10exp(+15) GeV) scale, follows that the neutrinoless double-beta decay is
ruled by the Majorana neutrino mass mechanism. Within this notion, for the
inverted neutrino-mass hierarchy we derive allowed ranges of half-lives of the
neutrinoless double-beta decay for nuclei of experimental interest with
different sets of nuclear matrix elements. The present-day results of the
calculation of the neutrinoless double-beta decay nuclear matrix elements are
briefly discussed. We argue that if neutrinoless double-beta decay will be
observed in future experiments sensitive to the effective Majorana mass in the
inverted mass hierarchy region, a comparison of the derived ranges with
measured half-lives will allow us to probe the standard seesaw mechanism
assuming that future cosmological data will establish the sum of neutrino
masses to be about 0.2 eV.Comment: Some changes in sections I, II, IV, and V; two new figures;
additional reference
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