Security and entanglement in differential-phase-shift quantum key distribution.

Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2009.Quantum key distribution (QKD) aims at the creation of a secret key in the two locations of partners, traditionally Alice and Bob, wishing to communicate in private. A generic QKD protocol utilises a quantum channel and an authenticated classical channel for exchanges between partners in Phases 1 and 2 of the protocol, respectively. Phase 1 can be described as a prepareand- measure (P&M) or equivalently as an entanglement-based (EB) phase. Bob performs the same measurement in both descriptions. Subsequent to measurement, Phase 2 is commenced, the aim of which is to distill a secret key from the measurement outcomes resulting from Phase 1. A necessary condition for the security of a QKD protocol is that the measurement performed by Bob in Phase 1 must be described by non-commuting POVM elements. One method of proving the unconditional security of a QKD protocol is to show that the complete protocol (including Phases 1 and 2) is equivalent to an entanglement distillation protocol. A rst step towards showing such an equivalence for a given P&M QKD protocol is to describe an EB translation of Phase 1, where the condition on Bob's measurement is met. Di erential-phase-shift (DPS) QKD is a member of the class of distributedphase- reference QKD protocols. Unconditional security proofs for this class of protocols do not yet exist. Phase 1 of DPSQKD is here described and formalised as both a P&M and an EB phase, and Bob's measurement is shown to be described by non-commuting POVM elements. This description of an equivalent EB translation of DPSQKD where the condition on Bob's measurement is met, is a fi rst step towards a potential unconditional security proof for the protocol based on entanglement distillation

Pathways to cellular supremacy in biocomputing

Synthetic biology uses living cells as the substrate for performing human-defined computations. Many current implementations of cellular computing are based on the “genetic circuit” metaphor, an approximation of the operation of silicon-based computers. Although this conceptual mapping has been relatively successful, we argue that it fundamentally limits the types of computation that may be engineered inside the cell, and fails to exploit the rich and diverse functionality available in natural living systems. We propose the notion of “cellular supremacy” to focus attention on domains in which biocomputing might offer superior performance over traditional computers. We consider potential pathways toward cellular supremacy, and suggest application areas in which it may be found.A.G.-M. was supported by the SynBio3D project of the UK Engineering and Physical Sciences Research Council (EP/R019002/1) and the European CSA on biological standardization BIOROBOOST (EU grant number 820699). T.E.G. was supported by a Royal Society University Research Fellowship (grant UF160357) and BrisSynBio, a BBSRC/ EPSRC Synthetic Biology Research Centre (grant BB/L01386X/1). P.Z. was supported by the EPSRC Portabolomics project (grant EP/N031962/1). P.C. was supported by SynBioChem, a BBSRC/EPSRC Centre for Synthetic Biology of Fine and Specialty Chemicals (grant BB/M017702/1) and the ShikiFactory100 project of the European Union’s Horizon 2020 research and innovation programme under grant agreement 814408

Familial hypercholesterolaemia in children and adolescents from 48 countries: a cross-sectional study

Background: Approximately 450 000 children are born with familial hypercholesterolaemia worldwide every year, yet only 2·1% of adults with familial hypercholesterolaemia were diagnosed before age 18 years via current diagnostic approaches, which are derived from observations in adults. We aimed to characterise children and adolescents with heterozygous familial hypercholesterolaemia (HeFH) and understand current approaches to the identification and management of familial hypercholesterolaemia to inform future public health strategies. Methods: For this cross-sectional study, we assessed children and adolescents younger than 18 years with a clinical or genetic diagnosis of HeFH at the time of entry into the Familial Hypercholesterolaemia Studies Collaboration (FHSC) registry between Oct 1, 2015, and Jan 31, 2021. Data in the registry were collected from 55 regional or national registries in 48 countries. Diagnoses relying on self-reported history of familial hypercholesterolaemia and suspected secondary hypercholesterolaemia were excluded from the registry; people with untreated LDL cholesterol (LDL-C) of at least 13·0 mmol/L were excluded from this study. Data were assessed overall and by WHO region, World Bank country income status, age, diagnostic criteria, and index-case status. The main outcome of this study was to assess current identification and management of children and adolescents with familial hypercholesterolaemia. Findings: Of 63 093 individuals in the FHSC registry, 11 848 (18·8%) were children or adolescents younger than 18 years with HeFH and were included in this study; 5756 (50·2%) of 11 476 included individuals were female and 5720 (49·8%) were male. Sex data were missing for 372 (3·1%) of 11 848 individuals. Median age at registry entry was 9·6 years (IQR 5·8-13·2). 10 099 (89·9%) of 11 235 included individuals had a final genetically confirmed diagnosis of familial hypercholesterolaemia and 1136 (10·1%) had a clinical diagnosis. Genetically confirmed diagnosis data or clinical diagnosis data were missing for 613 (5·2%) of 11 848 individuals. Genetic diagnosis was more common in children and adolescents from high-income countries (9427 [92·4%] of 10 202) than in children and adolescents from non-high-income countries (199 [48·0%] of 415). 3414 (31·6%) of 10 804 children or adolescents were index cases. Familial-hypercholesterolaemia-related physical signs, cardiovascular risk factors, and cardiovascular disease were uncommon, but were more common in non-high-income countries. 7557 (72·4%) of 10 428 included children or adolescents were not taking lipid-lowering medication (LLM) and had a median LDL-C of 5·00 mmol/L (IQR 4·05-6·08). Compared with genetic diagnosis, the use of unadapted clinical criteria intended for use in adults and reliant on more extreme phenotypes could result in 50-75% of children and adolescents with familial hypercholesterolaemia not being identified. Interpretation: Clinical characteristics observed in adults with familial hypercholesterolaemia are uncommon in children and adolescents with familial hypercholesterolaemia, hence detection in this age group relies on measurement of LDL-C and genetic confirmation. Where genetic testing is unavailable, increased availability and use of LDL-C measurements in the first few years of life could help reduce the current gap between prevalence and detection, enabling increased use of combination LLM to reach recommended LDL-C targets early in life

A Necessary Condition for the Security of Coherent- One-Way Quantum Key Distribution Protocol

The coherent-one-way and the differential-phase-shift protocols are two of the most recent practical quantum key distribution protocols for quantum cryptography. These protocols belong to a class of so-called distributed-phase-reference quantum key distribution protocols. While security proofs for some limited attacks exist, the unconditional security proofs this class of protocol remain unrealised. The existing tools for proving security of protocols against the most general attacks fail to apply to this class of protocol in a straight forward way. One of the necessary conditions for a quantum key distribution protocol to be secure is the presence of noncommuting measurements. In this paper, the coherent-one-way protocol is formalised, and we describe Bob’s measurements by non-commuting POVM elements, showing that this security condition is met

Diversity of participant representation within the 66th Lindau Nobel Laureate Meeting

The 66th Lindau Nobel Laureate Meeting (LiNo16) was dedicated to the field of physics. A total of 29 Nobel Laureates, 1 A.M. Turing Award recipient and 400 young scientists attended LiNo16 in Lindau, Germany. Young scientists from 80 countries attended the meeting. Out of the 400 young scientists at the meeting, only 30% were women scientists, and only one of the Nobel Laureate attendees was a woman. Natural sciences have often been dominated by a single stereotype: white men from predominantly Western or developed countries. Although a lot is being done to increase human capacity in the sciences in the less developed and developing world, it has become apparent that there is a persistent lack of diversity in the sciences.1,2 Extensive studies have also revealed that the rate of participation of women and minority groups in science, technology, engineering and mathematics (STEM) is significantly lower than the representation of women and minorities in society at large. As a strategy to improve women and minority representation, more countries are encouraging the involvement of these groups in science from a young age – a strategy which is the norm in many developed countries and which has been shown to have a positive correlation with high representativity of women and minority groups. It is evident that global scientific collaborations encourage unity and inclusion regardless of power, race, beliefs and gender.3,4 It has become imperative for society to be well capacitated in order to deal with global issues. The exclusion of certain groups based on gender and race, among other factors, means the game is played with less than half of the team. Diversity should be the basis for increased collaboration and not grounds for marginalisation. Nowotny et al.5 describe diversity as a prominent theme in science and technology to determine technical processes, economic systems and social structures. Since 1951, 350 Nobel Laureates have committed to the exchange among scientists with the aim of fostering education, inspiration and connection,6 leveraging on diversity for increased scientific output as a result of collaboration and sharing of best practice experiences. This initiative, which is realised through annual meetings, has fostered and increased exchange amongst young scientists within their respective fields by exposure to a diversity of thinkers and new ideas. The meetings have encouraged global engagement on the unprecedented scale of the global problems we face today. Furthermore, the meetings enable the exploration and encouragement of the scientific diversity that lies in the world and the potential for addressing global issues. We analysed diversity in terms of representation of gender and countries of origin at the 66th Lindau Nobel Laureate Meeting. Additionally, we ponder here on the lessons that came with the meeting. It is expected that our analysis will help to sensitise, motivate and improve the number of women and underrepresented regions with respect to participation in STEM meetings and forums. A diversity of attendees ensures a balanced benefit from the lessons that are acquired during such meetings. Through diversity, we believe that current scientific global challenges can be re-evaluated and innovations towards solutions developed more objectively, independent of gender, beliefs and race bia

New Pathogenicity Marker Found in the Plasticity Region of the Helicobacter pylori Genome

Comparison of gastric carcinoma and gastritis isolates showed the presence of genes, probably carcinoma associated (JHP947 and JHP940), that are situated in a Helicobacter pylori genome region (45 kb in J99 and 68 kb in 26695) called the “plasticity region.” This region presents a great variability of DNA sequences. We investigated, by PCR, the presence of the JHP940 and JHP947 genes, as well as the presence of a third gene which seems to be associated with gastritis (HP986), on H. pylori strains isolated from 200 Brazilian patients, 79 of whom had gastric carcinomas and 53 of whom had duodenal ulcers, to confirm this association. Gastritis isolates (n = 68) were included as a control. We also evaluated if these genes were related to the virulence-associated cagA genotype. The present methodology did not permit definitive conclusions to be reached regarding the association between the JHP940 gene and gastric carcinoma or between the HP986 gene and gastritis. However, we showed that the JHP947 gene might be implicated in the development of both duodenal ulcer and gastric carcinoma. The presence of the JHP947 gene was associated with the cagA-positive genotype. The JHP947 gene is a novel virulence marker candidate of H. pylori

The future of quantum biology

Biological systems are dynamical, constantly exchanging energy and matter with the environment in order to maintain the non-equilibrium state synonymous with living. Developments in observational techniques have allowed us to study biological dynamics on increasingly small scales. Such studies have revealed evidence of quantum mechanical effects, which cannot be accounted for by classical physics, in a range of biological processes. Quantum biology is the study of such processes, and here we provide an outline of the current state of the field, as well as insights into future directions