Quantum cryptography: a practical information security perspective

Quantum Key Exchange (QKE, also known as Quantum Key Distribution or QKD) allows communicating parties to securely establish cryptographic keys. It is a well-established fact that all QKE protocols require that the parties have access to an authentic channel. Without this authenticated link, QKE is vulnerable to man-in-the-middle attacks. Overlooking this fact results in exaggerated claims and/or false expectations about the potential impact of QKE. In this paper we present a systematic comparison of QKE with traditional key establishment protocols in realistic secure communication systems.Comment: 5 pages, new title, published version, minor changes onl

The New Cornwall syenogranite, Nova Scotia: petrology and geochemistry

The New Cornwall syenogranite is a 1.7 km2 intrusion at the southern margin of the Whale Lake monzogranitc of the South Mountain Batholilh of southwestern Nova Scotia- It has a mean SiO2 content of 75 8%, and contains accessory amounts of tourmaline, andalusite, and primary muscovitc. Ratios such as A/CNK (~ 1.25). Rb/K (~215), and Nb/Ta (- 3.5) show that the syenogranitc is not highly fractionated. Although binary clement plots for some elements show the same regular trend for both monzogranite and syenogranite, variations in trace elements such as Rb, Ha, Th and LREE show that the syenogranite is not derived from the monzogranite by fractional crystalli7ation, as the syenogranite has lower Eu and HREE compared with the monzogranite. Similarities in LREE, Nd isotope composition (ℇNd ~ -2) and other geochemical indicators between monzogranite and syenogranitc suggest that they were derived by partial melting of a common source Both the Whale Lake monzogranite and the New Cornwall syenogranite then evolved independently by fractional crystallization and late fluids played only a minor role in the further evolution of the syenogranitc. This represents a third mode of development of mineralized leucogranite in the South Mountain Batholith, in addition to the previously recognized "associated" and "independent" leucogranitc RÉSUMÉ Le syénogranitc de New Cornwall constituc une intrusion de 1.7 kilomètre carré sur la limite méridionale du granite monzonitique du lac Whale, lequcl fait panic du batholithe du mont South, dans le sud-ouest de la Nouvelle-Écosse. Il a une teneur moyenne en Si02 de 75.8 %, et renferme des quantités accessoires de tourmaline, d'andalousite et de muscovite primaire. Les rapports d'A/CNK (~ 1,25), de Rb/K (~ 215) et de Nb/Ta (~ 3,5) révèlent que le syénogranite n'est pas extrémement fractionné. Même si les représentaions graphiques des éléments binaires de certains éléments révèlent la même tendance régulière dans le cas du granite monzonitique et du syénogranite, les variations des éléments traces comme le Rb, lc Ba, lc Th et les éléments de terres rares légers signalent que le syénogranite ne provient pas du granite monzonitique par cristallisation fractionnairc, car le syénogranite posséde des teneurs moindres en Eu et en éléments de terres rares légerds, la comparativement au granite monzonitique. Les similantés existantes en ce qui conceme les éléments de terres rares légers, la composition en isotopes de Nd (ℇNd ~ -2) et d'autres mdicatcurs gêochimiques entrc le granite monzonitique et le syénogranite permettent de supposer qu'ils proviennent d'une fonte partielle d'une source commune. Le granite monzonitique du lac Whale et le syénogranite de New Cornwall ont ensuite tous deux évolué indépendamment par cristallisation fractionnaire et lcs fluides tardifs ont seulement joué un rôle secondairé dans l'évolution ulténeure du syénogranite. Il s'agit la d'un troisieme mode de développemcnt du leucogranitc minéralisé dans le batholithe du mont South, qui s'ajoute aux leucogranites « assoaés » et « indépendants » dèjà rcconnus Traduit par la rédactio

Measuring antibody coatings on gold nanoparticles by optical spectroscopy

The adsorption of antibodies onto gold nanoparticles to make gold–antibody conjugates is finding application in multiple areas. Gold–antibody conjugates for use in malaria diagnostics were prepared and a method of characterisation that can be applied to any gold–protein conjugate was developed. When protein adsorbs onto a gold nanoparticle, it changes the local refractive index and so changes the surface plasmon resonance of the gold particle. Changes to the surface plasmon resonance manifest in the absorbance spectrum of the conjugates. This was measured by optical spectroscopy and relatively simple equations to convert spectral shifts to predictions of the protein layer thickness and mass coverage are presented. As with most protein adsorption reported in the literature, the results showed the protein adsorption to depend on antibody concentration, reaching a plateau at around 1 μg ml−1. The coverage was estimated to be approximately 2–3 mg m−2 and the coating thickness estimates were approximately 10 nm, which is consistent with active antibody. The results suggested more antibody was used in conjugate preparation than was necessary for complete coverage of the gold. This excess antibody could bind to the target antigen to reduce malaria test sensitivity. A key advantage of this characterisation method is that it is sufficiently simple to be used for quality control of conjugate production and the equations presented can be applied to other coatings on gold nanoparticles

Novel models to predict elevated intracranial pressure during intensive care and long-term neurological outcome after TBI

status: publishe

Agreement between expert thoracic radiologists and the chest radiograph reports provided by consultant radiologists and reporting radiographers in clinical practice: review of a single clinical site

Introduction: To compare the clinical chest radiograph (CXR) reports provided by consultant radiologists and reporting radiographers with expert thoracic radiologists. Methods: Adult CXRs (n=193) from a single site were included; 83% randomly selected from CXRs performed over one year, and 17% selected from the discrepancy meeting. Chest radiographs were independently interpreted by two expert thoracic radiologists (CTR1/2).Clinical history, previous and follow-up imaging was available, but not the original clinical report. Two arbiters compared expert and clinical reports independently. Kappa (Ƙ), Chi Square (χ2) and McNemar tests were performed to determine inter-observer agreement. Results: CTR1 interpreted 187 (97%) and CTR2 186 (96%) CXRs, with 180 CXRs interpreted by both experts. Radiologists and radiographers provided 93 and 87 of the original clinical reports respectively. Consensus between both expert thoracic radiologists and the radiographer clinical report was 70 (CTR1;Ƙ=0.59) and 70 (CTR2; Ƙ=0.62), and comparable to agreement between expert thoracic radiologists and the radiologist clinical report (CTR1=76,Ƙ=0.60; CTR2=75, Ƙ=0.62). Expert thoracic radiologists agreed in 131 cases (Ƙ=0.48). There was no difference in agreement between either expert thoracic radiologist, when the clinical report was provided by radiographers or radiologists (CTR1 χ=0.056, p=0.813; CTR2 χ=0.014, p=0.906), or when stratified by inter-expert agreement; radiographer McNemar p=0.629 and radiologist p=0.701. Conclusion: Even when weighted with chest radiographs reviewed at discrepancy meetings, content of CXR reports from trained radiographers are comparable to the content of reports issued by radiologists and expert thoracic radiologists