1,018 research outputs found
SiPM used as fast Photon-Counting Module and for Multiphoton Detection
We demonstrate fast counting and multiphoton detection abilities of a Silicon
Photo Multiplier (SiPM). In fast counting mode we are able to detect two
consecutive photons separated by only 2.3 ns corresponding to 430 MHz. The
counting efficiency for small optical intensities at a wavelength of 532 nm was
found to be around 8.3% with a dark count rate of 50 kHz at T=-7 degrees
Celsius. Using the SiPM in multiphoton detection mode, we find a good signal
discrimination for different numbers of simultaneous detected photons.Comment: 11 pages, 13 figure
Swiss ethnoveterinary knowledge on medicinal plants - a within-country comparison of Italian speaking regions with north-western German speaking regions
BACKGROUND:
Ethnoveterinary knowledge in Europe may play an important role as a basis for sustainable treatment options for livestock. Aims of our study were (a) to compare the ethnoveterinary practices of two culturally and sociodemographically different regions of Switzerland, (b) to compare results with earlier ethnoveterinary studies conducted in Switzerland and in adjacent Italian regions and, (c) to evaluate possible reasons for regional differences in European ethnoveterinary medicine.
METHODS:
25 interviews were conducted in 2014 in all Italian speaking regions (ItR) of Switzerland, and 31 interviews were held in five north-western German speaking Cantons (GeC). Semi-structured questionnaires were used to collect detailed information regarding plant species, mode of preparation, dosage, route of administration, category of use, origin of knowledge, frequency of use, and satisfaction with outcomes of the treatments.
RESULTS:
A total of 162 homemade remedies in ItR and 219 in GeC were reported, out of which 125 and 145, respectively, were reported to contain only one plant species (homemade single species herbal remedy report, HSHR). 44 ItR and 43 GeC plant species were reported to treat livestock, of which only a half were used in both regions. For each HSHR, we classified the treatment intention of all use reports (UR), leading to a total of 205 and 219 UR in ItR and GeC respectively. While cattle were the most often treated livestock species in both study regions, in ItR 40% of UR were administered to small ruminants. Main indications in both regions were gastrointestinal diseases and skin afflictions, but in ItR a high number of URs were reported as antiparasitics. URs were mainly handed down from the past generation, but in GeC the source of knowledge for 20% of URs were from courses. Regarding the used plant species, ItR showed a higher concordance with Swiss than Italian studies, but with some differences to all regions. A total of 22 (14 ItR; 8 GeC) plant species in this study have not been reported before in ethnoveterinary studies of Swiss and Italian alpine regions.
CONCLUSIONS:
ItR and GeC, show differences and similarities with respect to their own ethnoveterinary practices and earlier Swiss and Italian ethnoveterinary studies. Linguistic, geographical, as well as social and farm-structural conditions influence the regional ethnoveterinary knowledge. However, political borders seem to be more important than language or geographical barriers
Dispersion spreading of biphotons in optical fibres and two-photon interference
We present the first observation of two-photon polarization interference
structure in the second-order Glauber's correlation function of two-photon
light generated via type-II spontaneous parametric down-conversion. In order to
obtain this result, two-photon light is transmitted through an optical fibre
and the coincidence distribution is analyzed by means of the START-STOP method.
Beyond the experimental demonstration of an interesting effect in quantum
optics, these results also have considerable relevance for quantum
communications.Comment: Accepted for publication in Phys.Rev.Let
FRESH GAS UTILIZATION OF EIGHT CIRCLE SYSTEMS
The fresh gas utilization (FGU) of a semi-closed breathing system is defined as the ratio of the amount of gas reaching the patient's lungs to the total amount of fresh gas flowing into the breathing system. It indicates to what extent a breathing system conserves anaesthetic gases and provides inspired gas concentrations as close as possible to those in the fresh gas, even at low fresh gas flows (FGF). We have measured FGU in eight circle systems used conventionally in Europe: Drager Cicero, Drager Sulla 808V with circle system 8 ISO and ventilator Ventilog, Drager AV1, Ohmeda Modulus II Plus, Gambro Engstrdm Elsa, Siemens Servo Ventilator 900 D with circle system 985, Siemens Ventilator 710 and Megamed 700A with circle system 219. The Tests were performed according to the Draft European Standard ‘Anaesthetic Workstations and Their Modules'. None of the systems tested showed the characteristics of an ideal system which would reach 100% FGU with an FGF less than minute volume. At FGF 3 litre min−1, FGU was: Gambro Engstrdm Elsa 97.8% Siemens Servo Ventilator 900 D with circle system 96.1 %, Drager Cicero 93.4%, Ohmeda Modulus II Plus 93.1 %, Drager 8 ISO 92.3%, Drager AVI 87.6%, Megamed 700A 77.0% and Siemens Ventilator 710 74.1
Long-Distance Entanglement Distribution with Single-Photon Sources
We present an efficient architecture for quantum repeaters based on
single-photon sources in combination with quantum memories for photons. Errors
inherent to previous repeater protocols using photon-pair sources are
eliminated, leading to a significant gain in efficiency. We establish the
requirements on the single-photon sources and on the photon detectors.Comment: 4 pages, 1 figure, 1 tabl
Distribution of time-bin qubits over 50 km of optical fiber
We report experimental distribution of time-bin entangled qubits over 50 km
of optical fibers. Using actively stabilized preparation and measurement
devices we demonstrate violation of the CHSH Bell inequality by more than 15
standard deviations without removing the detector noise. In addition we report
a proof of principle experiment of quantum key distribution over 50 km of
optical fibers using entangled photon.Comment: 4 pages, 4 figure
Long distance quantum teleportation in a quantum relay configuration
A long distance quantum teleportation experiment with a fiber-delayed Bell
State Measurement (BSM) is reported. The source creating the qubits to be
teleported and the source creating the necessary entangled state are connected
to the beam splitter realizing the BSM by two 2 km long optical fibers. In
addition, the teleported qubits are analyzed after 2,2 km of optical fiber, in
another lab separated by 55 m. Time bin qubits carried by photons at 1310 nm
are teleported onto photons at 1550 nm. The fidelity is of 77%, above the
maximal value obtainable without entanglement. This is the first realization of
an elementary quantum relay over significant distances, which will allow an
increase in the range of quantum communication and quantum key distribution.Comment: 4 pages, submitte
Phase noise measurements in long fiber interferometers for quantum repeaters applications
Many protocols for long distance quantum communication require
interferometric phase stability over long distances of optical fibers. In this
paper we investigate the phase noise in long optical fibers both in laboratory
environment and in installed commercial fibers in an urban environment over
short time scales (up to hundreds of us). We show that the phase fluctuations
during the travel time of optical pulses in long fiber loops are small enough
to obtain high visibility first order interference fringes in a Sagnac
interferometer configuration for fiber lengths up to 75 km. We also measure
phase fluctuations in a Mach-Zehnder interferometer in installed fibers with
arm length 36.5 km. We verify that the phase noise respects gaussian
distribution and measure the mean phase change as a function of time
difference. The typical time needed for a mean phase change of 0.1 rad is of
order of 100 us, which provides information about the time scale available for
active phase stabilization. Our results are relevant for future implementations
of quantum repeaters in installed optical fiber networks.Comment: 9 pages with 10 figure
Experimental Test of Relativistic Quantum State Collapse with Moving Reference Frames
An experimental test of relativistic wave-packet collapse is presented. The
tested model assumes that the collapse takes place in the reference frame
determined by the massive measuring detectors. Entangled photons are measured
at 10 km distance within a time interval of less than 5 ps. The two apparatuses
are in relative motion so that both detectors, each in its own inertial
reference frame, are first to perform the measurement. The data always
reproduces the quantum correlations and thus rule out a class of collapse
models. The results also set a lower bound on the "speed of quantum
information" to 0.66 x 10^7 and 1.5 x 10^4 times the speed of light in the
Geneva and the background radiation reference frames, respectively. The very
difficult and deep question of where the collapse takes place - if it takes
place at all - is considered in a concrete experimental context.Comment: 4 pages + 2 ps figure
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