856 research outputs found
C1 inhibitor deficiency: 2014 United Kingdom consensus document
C1 inhibitor deficiency is a rare disorder manifesting with recurrent attacks of disabling and potentially life-threatening angioedema. Here we present an updated 2014 United Kingdom consensus document for the management of C1 inhibitor-deficient patients, representing a joint venture between the United Kingdom Primary Immunodeficiency Network and Hereditary Angioedema UK. To develop the consensus, we assembled a multi-disciplinary steering group of clinicians, nurses and a patient representative. This steering group first met in 2012, developing a total of 48 recommendations across 11 themes. The statements were distributed to relevant clinicians and a representative group of patients to be scored for agreement on a Likert scale. All 48 statements achieved a high degree of consensus, indicating strong alignment of opinion. The recommendations have evolved significantly since the 2005 document, with particularly notable developments including an improved evidence base to guide dosing and indications for acute treatment, greater emphasis on home therapy for acute attacks and a strong focus on service organisation. This article is protected by copyright. All rights reserved
Avoiding the Detector Blinding Attack on Quantum Cryptography
We show the detector blinding attack by Lydersen et al [1] will be
ineffective on most single photon avalanche photodiodes (APDs) and certainly
ineffective on any detectors that are operated correctly. The attack is only
successful if a redundant resistor is included in series with the APD, or if
the detector discrimination levels are set inappropriately
Practical quantum key distribution: On the security evaluation with inefficient single-photon detectors
Quantum Key Distribution with the BB84 protocol has been shown to be
unconditionally secure even using weak coherent pulses instead of single-photon
signals. The distances that can be covered by these methods are limited due to
the loss in the quantum channel (e.g. loss in the optical fiber) and in the
single-photon counters of the receivers. One can argue that the loss in the
detectors cannot be changed by an eavesdropper in order to increase the covered
distance. Here we show that the security analysis of this scenario is not as
easy as is commonly assumed, since already two-photon processes allow
eavesdropping strategies that outperform the known photon-number splitting
attack. For this reason there is, so far, no satisfactory security analysis
available in the framework of individual attacks.Comment: 11 pages, 6 figures; Abstract and introduction extended, Appendix
added, references update
Autocompensating Quantum Cryptography
Quantum cryptographic key distribution (QKD) uses extremely faint light
pulses to carry quantum information between two parties (Alice and Bob),
allowing them to generate a shared, secret cryptographic key. Autocompensating
QKD systems automatically and passively compensate for uncontrolled time
dependent variations of the optical fiber properties by coding the information
as a differential phase between orthogonally-polarized components of a light
pulse sent on a round trip through the fiber, reflected at mid-course using a
Faraday mirror. We have built a prototype system based on standard telecom
technology that achieves a privacy-amplified bit generation rate of ~1000
bits/s over a 10-km optical fiber link. Quantum cryptography is an example of
an application that, by using quantum states of individual particles to
represent information, accomplishes a practical task that is impossible using
classical means.Comment: 18 pages, 6 figures, 1 table. Submitted to the New Journal of Physic
Efficient generation of tunable photon pairs at 0.8 and 1.6 micrometer
We demonstrate efficient generation of collinearly propagating, highly
nondegenerate photon pairs in a periodically-poled lithium niobate cw
parametric downconverter with an inferred pair generation rate of 1.4*10^7/s/mW
of pump power. Detection of an 800-nm signal photon triggers a
thermoelectrically-cooled 20%-efficient InGaAs avalanche photodiode for the
detection of the 1600-nm conjugate idler photon. Using single-mode fibers as
spatial mode filters, we obtain a signal-conditioned idler-detection
probability of about 3.1%.Comment: 8 pages, 3 figure
Performance of various quantum key distribution systems using 1.55 um up-conversion single-photon detectors
We compare the performance of various quantum key distribution (QKD) systems
using a novel single-photon detector, which combines frequency up-conversion in
a periodically poled lithium niobate (PPLN) waveguide and a silicon avalanche
photodiode (APD). The comparison is based on the secure communication rate as a
function of distance for three QKD protocols: the Bennett-Brassard 1984 (BB84),
the Bennett, Brassard, and Mermin 1992 (BBM92), and the coherent differential
phase shift keying (DPSK). We show that the up-conversion detector allows for
higher communication rates and longer communication distances than the commonly
used InGaAs/InP APD for all the three QKD protocols.Comment: 9 pages, 9 figure
Targeted capture of Dreb subfamily genes as candidates genes for drought tolerance polymorphism in natural population of Coffea canephora.
Coffea canephora, (Robusta), provides 33% of worldwide coffee production, 80% and 22% of Ugandan and Brazilian coffee production, respectively. Abiotic stress such as temperature variations or drought periods, aggravated by climate changes, are factors that affect this production. This sensitivity threatens both the steady supply of quality coffees and the livelihood of millions of people producing coffee. The natural genetic diversity of C. canephora offer a potential for detecting new genetic variants related to drought adaptation. In particular, modifications occurring in genes related to abiotic stress tolerance make these genes candidate for breeding programs in order to enhance the resilience to climate change
High-efficiency, high-power difference-frequency generation of 0.9–1.5 μm light in BBO
An efficient method for generation of high energy pulsed ir light between 0.9 and 1.5 ÎĽm is described. The technique uses difference frequency mixing of pulsed, visible dye and Nd:YAG laser light in a 10 mm long BBO crystal. Quantum efficiencies of up to 23% and ir pulse energies up to 4.5 mJ are demonstrated. The low shot-to-shot fluctuations of difference frequency generation in BBO make this technique an attractive alternative to the conventional optical parametric oscillator or Raman shifting methods that are currently used to access this spectral region
- …