Cheat Sensitive Quantum Bit Commitment

We define cheat sensitive cryptographic protocols between mistrustful parties as protocols which guarantee that, if either cheats, the other has some nonzero probability of detecting the cheating. We give an example of an unconditionally secure cheat sensitive non-relativistic bit commitment protocol which uses quantum information to implement a task which is classically impossible; we also describe a simple relativistic protocol.Comment: Final version: a slightly shortened version of this will appear in PRL. Minor corrections from last versio

Coin Tossing is Strictly Weaker Than Bit Commitment

We define cryptographic assumptions applicable to two mistrustful parties who each control two or more separate secure sites between which special relativity guarantees a time lapse in communication. We show that, under these assumptions, unconditionally secure coin tossing can be carried out by exchanges of classical information. We show also, following Mayers, Lo and Chau, that unconditionally secure bit commitment cannot be carried out by finitely many exchanges of classical or quantum information. Finally we show that, under standard cryptographic assumptions, coin tossing is strictly weaker than bit commitment. That is, no secure classical or quantum bit commitment protocol can be built from a finite number of invocations of a secure coin tossing black box together with finitely many additional information exchanges.Comment: Final version; to appear in Phys. Rev. Let

Unconditionally Secure Bit Commitment

We describe a new classical bit commitment protocol based on cryptographic constraints imposed by special relativity. The protocol is unconditionally secure against classical or quantum attacks. It evades the no-go results of Mayers, Lo and Chau by requiring from Alice a sequence of communications, including a post-revelation verification, each of which is guaranteed to be independent of its predecessor.Comment: Typos corrected. Reference details added. To appear in Phys. Rev. Let

The Effects of Embedded Dipoles in Aromatic Self-Assembled Monolayers

Using a representative model system, here electronic and structural properties of aromatic self-assembled monolayers (SAMs) are described that contain an embedded, dipolar group. As polar unit, pyrimidine is used, with its orientation in the molecular backbone and, consequently, the direction of the embedded dipole moment being varied. The electronic and structural properties of these embedded-dipole SAMs are thoroughly analyzed using a number of complementary characterization techniques combined with quantum-mechanical modeling. It is shown that such mid-chain-substituted monolayers are highly interesting from both fundamental and application viewpoints, as the dipolar groups are found to induce a potential discontinuity inside the monolayer, electrostatically shifting the core-level energies in the regions above and below the dipoles relative to one another. These SAMs also allow for tuning the substrate work function in a controlled manner independent of the docking chemistry and, most importantly, without modifying the SAM-ambient interface

Progress towards the UNAIDS 90–90-90 goals by age and gender in a rural area of KwaZulu-Natal, South Africa: a household-based community cross-sectional survey

Abstract Background The Joint United Nations Programme on HIV/AIDS (UNAIDS) has developed an ambitious strategy to end the AIDS epidemic. After eight years of antiretroviral therapy (ART) program we assessed progress towards the UNAIDS 90–90-90 targets in Mbongolwane and Eshowe, KwaZulu-Natal, South Africa. Methods We conducted a cross-sectional household-based community survey using a two-stage stratified cluster probability sampling strategy. Persons aged 15–59 years were eligible. We used face-to-face interviewer-administered questionnaires to collect information on history of HIV testing and care. Rapid HIV testing was performed on site and venous blood specimens collected from HIV-positive participants for antiretroviral drug presence test, CD4 count and viral load. At the time of the survey the CD4 threshold for ART initiation was 350 cells/μL. We calculated progression towards the 90–90-90 UNAIDS targets by estimating three proportions: HIV positive individuals who knew their status (first 90), those diagnosed who were on ART (second 90), and those on ART who were virally suppressed (third 90). Results We included 5649/6688 (84.5%) individuals. Median age was 26 years (IQR: 19–40), 62.3% were women. HIV prevalence was 25.2% (95% CI: 23.6–26.9): 30.9% (95% CI: 29.0–32.9) in women; 15.9% (95% CI: 14.0–18.0) in men. Overall progress towards the 90–90-90 targets was as follows: 76.4% (95% CI: 74.1–78.6) knew their status, 69.9% (95% CI: 67.0–72.7) of those who knew their status were on ART and 93.1% (95% CI: 91.0–94.8) of those on ART were virally suppressed. By sex, progress towards the 90–90-90 targets was: 79%–71%–93% among women; and 68%–68%–92% among men (p-values of women and men comparisons were < 0.001, 0.443 and 0.584 respectively). By age, progress was: 83%–75%–95% among individuals aged 30–59 years and 64%–58%–89% among those aged 15–29 years (p-values of age groups comparisons were < 0.001, < 0.001 and 0.011 respectively). Conclusions In this context of high HIV prevalence, significant progress has been achieved with regards to reaching the UNAIDS 90–90-90 targets. The third 90, viral suppression in people on ART, was achieved among women and men. However, gaps persist in HIV diagnosis and ART coverage particularly in men and individuals younger than 30 years. Achieving 90–90-90 is feasible but requires additional investment to reach youth and men

Syndactyly in Pigs: A Review of Previous Research and the Presentation of Eight Archaeological Specimens

This paper reviews evidence for the rare condition of porcine syndactyly. It describes eight archaeological examples from Britain, Northern Ireland and France. Syndactyly refers to the partial or complete fusion of two or more adjacent phalanges on the medio-lateral border. The degree and character of fusion are variable, but phalanges frequently unite to create a single skeletal element. This condition has been identified by veterinarians, zoologists and naturalists in individuals and populations in a range of species, but in spite of substantial research on the condition in humans and to a lesser extent cattle, it remains relatively poorly understood in other mammals. Syndactyly is generally agreed to be primarily congenital in origin, although factors affecting its incidence remain far from fully understood. In light of the general paucity of discussion of specific conditions of animal palaeopathology, this paper presents an analysis of these newly discovered syndactyle pig specimens, offers a review of research with particular reference to pigs and discusses the etiology of the condition

Vaccine efficacy of ALVAC-HIV and bivalent subtype C gp120–MF59 in adults

BACKGROUND : A safe, effective vaccine is essential to eradicating human immunodeficiency virus (HIV) infection. A canarypox–protein HIV vaccine regimen (ALVAC-HIV plus AIDSVAX B/E) showed modest efficacy in reducing infection in Thailand. An analogous regimen using HIV-1 subtype C virus showed potent humoral and cellular responses in a phase 1–2a trial in South Africa. Efficacy data and additional safety data were needed for this regimen in a larger population in South Africa. METHODS : In this phase 2b–3 trial, we randomly assigned 5404 adults without HIV-1 infection to receive the vaccine (2704 participants) or placebo (2700 participants). The vaccine regimen consisted of injections of ALVAC-HIV at months 0 and 1, followed by four booster injections of ALVAC-HIV plus bivalent subtype C gp120–MF59 adjuvant at months 3, 6, 12, and 18. The primary efficacy outcome was the occurrence of HIV-1 infection from randomization to 24 months. RESULTS : In January 2020, prespecified criteria for non-efficacy were met at an interim analysis; further vaccinations were subsequently halted. The median age of the trial participants was 24 years; 70% of the participants were women. The incidence of adverse events was similar in the vaccine and placebo groups. During the 24-month followup, HIV-1 infection was diagnosed in 138 participants in the vaccine group and in 133 in the placebo group (hazard ratio, 1.02; 95% confidence interval, 0.81 to 1.30; P = 0.84). CONCLUSIONS : The ALVAC–gp120 regimen did not prevent HIV-1 infection among participants in South Africa despite previous evidence of immunogenicity.Supported by grants (HHSN272201300033C and HHSN272201600012C) to Novartis Vaccines and Diagnostics (now part of the GlaxoSmithKline [GSK] Biologicals) by the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health (NIH) for the selection and process development of the two gp120 envelope proteins TV1.C and 1086.C; by the Bill and Melinda Gates Foundation Global Health Grant (OPP1017604) and NIAID for the manufacture and release of the gp120 clinical grade material; and by U.S. Public Health Service Grants — UM1 AI068614 to the HIV Vaccine Trials Network (HVTN), UM1 AI068635 to the HVTN Statistical and Data Management Center, and UM1 AI068618 to the HVTN Laboratory Center — from the NIAID. GSK Biologicals contributed financially to the provision of preexposure prophylaxis to trial participants. The South African Medical Research Council supported its affiliated research sites.http://www.nejm.orgam2022School of Health Systems and Public Health (SHSPH

Herstellung und Charakterisierung von gemischten Monolagen mit Dipol-, Quadrupol- und Charge-Transfer-Wechselwirkungen

Der Fokus der Arbeit liegt auf der Untersuchung von Wechselwirkungen zwischen Molekülen in selbst-anordnenden Monolagen (SAMs) auf Goldoberflächen mittels Rastertunnelmikroskopie und komplementären Methoden wie z.B. Infrarot-Reflektions-Absorptions-Spektro-skopie. In dieser Arbeit wurde das kürzlich etablierte Konzept von eingebetteten Dipolmomenten in aromatischen, SAM-bildenden Molekülen eingehender untersucht. Das Ausmaß des Dipol-moments und die Größe der SAM-bildenden Moleküle wurden synthetisch variiert und der Einfluss auf die Struktur und elektronischen Eigenschaften der SAMs untersucht. Binäre, gemischte Monolagen aus SAM-bildenden Molekülen mit "entgegen gerichteten", Dipolmomenten wurden hergestellt und charakterisiert. Zur Herstellung der binären, gemischten Monolagen wurden zwei Methoden verwendet: die Monolagen wurden a) aus bereits gemischten Lösungen der Moleküle abgeschieden oder b) eine reine SAM in die Lösung des anderen Moleküls eingelegt, so dass ein Austausch stattfand. Der Vergleich der beiden Methoden ermöglicht Rückschlüsse über die Abscheidungsprozesse. Die Charakterisierung der SAMs dieser Mischungsreihen gab Aufschluss über Eigenschaften wie Packungsdichte, Austrittsarbeit, elektronischen Ladungstransport in Monolagen und Orientierung der Moleküle relativ zur Oberfläche und erlaubte Schlussfolgerungen über die Mischbarkeit und das Ausmaß der Dipolwechselwirkungen der Moleküle in der Monolage. In einem ähnlichen Ansatz zu dem oben beschriebenen Vorgehen wurden Quadrupolwechselwirkungen zwischen SAM-bildenen, Benzol-, Naphtalin- und Anthracenderivaten untersucht. In Mischungsreihen wurden SAMs von nicht- und teilweise (hoch)fluorierten, SAM-bildenden Molekülen auf Goldoberflächen charakterisiert. Die Ergebnisse der Untersuchungen können bei der gezielten Einstellung der elektronischen Eigenschaften in elektronischen Bauteilen wie OFETs Anwendung finden. In einem weiteren Projekt wurde der Einfluss von polaren Endgruppen auf die in situ Abspaltung von Schutzgruppen an Terphenylthiol-Derivaten untersucht, wobei die Ergebnisse zum Aufbau größerer, aus organischer Elektronik bestehender, Netzwerke verwendet werden können