4,377 research outputs found
Tomographic Quantum Cryptography Protocols are Reference Frame Independent
We consider the class of reference frame independent protocols in d
dimensions for quantum key distribution, in which Alice and Bob have one
natural basis that is aligned and the rest of their frames are unaligned. We
relate existing approaches to tomographically complete protocols. We comment on
two different approaches to finite key bounds in this setting, one direct and
one using the entropic uncertainty relation and suggest that the existing
finite key bounds can still be improved.Comment: Published version. 8 pages, 1 figur
Design ideation through improvised comedy processes
We argue that the processes of creating successful comedy are comparable to the processes of designing an innovative product. Our research explores how constructs of humour may be applied to the early phase of engineering design, when divergent thinking is assumed to be most valuable. During a series of exploratory workshops, the principles and processes of creating improvised comedy presented an opportunity to reinvigorate the design process, and overcome some of the common barriers to effective group brainstorming. This paper discusses the link between improvised comedy and design creativity, and the early development of a new improvisation-based approach to design ideation
Finite-key security against coherent attacks in quantum key distribution
The work by Christandl, K\"onig and Renner [Phys. Rev. Lett. 102, 020504
(2009)] provides in particular the possibility of studying unconditional
security in the finite-key regime for all discrete-variable protocols. We spell
out this bound from their general formalism. Then we apply it to the study of a
recently proposed protocol [Laing et al., Phys. Rev. A 82, 012304 (2010)]. This
protocol is meaningful when the alignment of Alice's and Bob's reference frames
is not monitored and may vary with time. In this scenario, the notion of
asymptotic key rate has hardly any operational meaning, because if one waits
too long time, the average correlations are smeared out and no security can be
inferred. Therefore, finite-key analysis is necessary to find the maximal
achievable secret key rate and the corresponding optimal number of signals.Comment: 9 pages, 4 figure
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Investigating TriHaloMethanes with respect to humidity
The disinfection of potable water has dramatically reduced the instances of Cholera and similar ailments within a population drawing upon that water source. There is however the possibility that Natural Organic Matter (NOM) can interact with the disinfection compounds to form Disinfection By-Products (DBP). One group of DBPs are Trihalomethanes (THMs) with several compounds of the group being suspected carcinogens. Within the UK the total concentration of all THMs within drinking water must not exceed 100µg/l.
At present water authorities take samples of the water supply and return them to a central laboratory for analysis. This provides an accurate test but one which can involve a long lead time in discovering a potential hazard to public health.
A Field Asymmetric Ion Mobility Spectrometer (FAIMS) sensor may be ideally placed to perform in situ continuous monitoring at particular sites. As part of a PhD co-sponsored by The Open University and Owlstone Nanotech Plc an investigation is ongoing to discover how sensitive a FAIMS device is with respect to THMs and humidity when sampling. Initial results and the method of data processing, which involves peak fitting to evolving spectra are presented
In Vitro Hydrodynamic Assessment of a New Transcatheter Heart Valve Concept (the TRISKELE)
This study presents the in vitro hydrodynamic assessment of the TRISKELE, a new system suitable for transcatheter aortic valve implantation (TAVI), aiming to mitigate the procedural challenges experienced with current technologies. The TRISKELE valve comprises three polymeric leaflet and an adaptive sealing cuff, supported by a novel fully retrievable self-expanding nitinol wire frame. Valve prototypes were manufactured in three sizes of 23, 26, and 29 mm by automated dip-coating of a biostable polymer, and tested in a hydrodynamic bench setup in mock aortic roots of 21, 23, 25, and 27 mm annulus, and compared to two reference valves suitable for equivalent implantation ranges: Edwards SAPIEN XT and Medtronic CoreValve. The TRISKELE valves demonstrated a global hydrodynamic performance comparable or superior to the controls with significant reduction in paravalvular leakage. The TRISKELE valve exhibits enhanced anchoring and improved sealing. The valve is currently under preclinical investigation
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Quantification of ethyl acetate using FAIMS
The enjoyment of wine is based not only on its flavour but also its aroma. The presence of compounds, such as ethyl acetate, can add a desirable depth of body, richness and sweetness to a wine. However, if the levels exceed the human perception threshold (100 - 200 mg/l) an aroma similar to acetone becomes prevalent and the wine is regarded as spoilt.A study was undertaken to determine the concentration of ethyl acetate within wine using a Gas Chromatograph coupled with Field Asymmetric Ion Mobility Spectrometry (FAIMS).
The use of FAIMS (also known as Differential Mobility Spectrometry) as a selective detector has increasingly become prevalent within analytical science. There is now a vibrant community of researchers working with the technique and different commercial systems are readily available. Two such systems are the Tourist and Lonestar instruments available from Owlstone Ltd. The Owlstone systems are characterised by the sensor being a solid state device, which imposes constraints on operational parameters but also offers opportunities over comparable devices.
FAIMS technology requires the interaction of compounds both within the ionisation and separation region. To influence the interactions in these two regions studies were completed at elevated (compared to ambient) pressures and humidity. The study of ethyl acetate within wine provided an opportunity to investigate these effects and also provided a route for optimisation of the instrument for the study.
It was found, in contrast to a previously reported investigation, that increasing the pressure resulted in a greater resolution of compounds. A more complicated relationship was observed with respect to humidity, believed attributable to water being an important constituent of reactive and product ion formation. Additional effects due to the presence of co-solvents were observed and subsequently managed so as to provide increased sensitivity.
The quantification of ethyl acetate within wine was accomplished considerably below the human perception threshold providing the opportunity to better manage this multifarious compound throughout manufacture and the product lifecycle
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Beagle 2: Mission to Mars — current status
Beagle 2, developed in the UK, was launched on June 2, 2003. It landed on Mars on December 25th, 2003 in Isidis Planitia, a large sedimentary basin. To date, the team is awaiting signals from the Beagle 2 lander. Current status of the mission will be reported
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Accessing and assessing lunar resources with PROSPECT
PROSPECT is a package in development by ESA to assess the in-situ resource potential of lunar regolith. PROSPECT will: obtain sub-surface regolith samples, extract volatiles, identify chemical species, quantify abundances, and characterize isotopes
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