An Ultra-Stable Referenced Interrogation System in the Deep Ultraviolet for a Mercury Optical Lattice Clock

We have developed an ultra-stable source in the deep ultraviolet, suitable to fulfill the interrogation requirements of a future fully-operational lattice clock based on neutral mercury. At the core of the system is a Fabry-P\'erot cavity which is highly impervious to temperature and vibrational perturbations. The mirror substrate is made of fused silica in order to exploit the comparatively low thermal noise limits associated with this material. By stabilizing the frequency of a 1062.6 nm Yb-doped fiber laser to the cavity, and including an additional link to LNE-SYRTE's fountain primary frequency standards via an optical frequency comb, we produce a signal which is both stable at the 1E-15 level in fractional terms and referenced to primary frequency standards. The signal is subsequently amplified and frequency-doubled twice to produce several milliwatts of interrogation signal at 265.6 nm in the deep ultraviolet.Comment: 7 pages, 6 figure

A Memetic Analysis of a Phrase by Beethoven: Calvinian Perspectives on Similarity and Lexicon-Abstraction

This article discusses some general issues arising from the study of similarity in music, both human-conducted and computer-aided, and then progresses to a consideration of similarity relationships between patterns in a phrase by Beethoven, from the first movement of the Piano Sonata in A flat major op. 110 (1821), and various potential memetic precursors. This analysis is followed by a consideration of how the kinds of similarity identified in the Beethoven phrase might be understood in psychological/conceptual and then neurobiological terms, the latter by means of William Calvin’s Hexagonal Cloning Theory. This theory offers a mechanism for the operation of David Cope’s concept of the lexicon, conceived here as a museme allele-class. I conclude by attempting to correlate and map the various spaces within which memetic replication occurs

The Anisotropic Bak-Sneppen model

The Bak-Sneppen model is shown to fall into a different universality class with the introduction of a preferred direction, mirroring the situation in spin systems. This is first demonstrated by numerical simulations and subsequently confirmed by analysis of the multitrait version of the model, which admits exact solutions in the extremes of zero and maximal anisotropy. For intermediate anisotropies, we show that the spatiotemporal evolution of the avalanche has a power law `tail' which passes through the system for any non-zero anisotropy but remains fixed for the isotropic case, thus explaining the crossover in behaviour. Finally, we identify the maximally anisotropic model which is more tractable and yet more generally applicable than the isotropic system

Frustrations of fur-farmed mink

Captive animals may suffer if strongly motivated to perform activities that their housing does not allow. We investigated this experimentally for caged mink, and found that they would pay high costs to perform a range of natural behaviours, and release cortisol if their most preferred activity, swimming, was prevented. Investigates the effect of limitations on caged mink. Popularity of fur farming; Research into the possible deprivation of mink, which result in their frustration; Details of the experiment; Impact of an access to water; Results which indicate that fur-farmed mink are still motivated to perform the same activities as their wild counterpart

Comparing identity, attitudes, and indicators of effectiveness in people who smoke, vape or use heated tobacco products: a cross-sectional study

Background: There is limited long-term and independent research on heated tobacco products (HTPs). We compared people who used HTPs with those who used nicotine vaping products (NVP) or cigarettes on smoker identity, indicators of effectiveness and, among NVP/HTP users, perceptions of these products. Methods: Adults exclusive cigarette smokers (N=45) and ex-smokers with medium/long-term (>3months) NVP (N=46) or HTP use (N=45) were recruited in London, UK. Participants completed a questionnaire assessing socio-demographics, smoking characteristics, smoker identity, dependence, intention to stop and attitudes towards HTP/NVP. Results: In adjusted analysis, people who used cigarettes (Mean Difference (MD)=1.4, 95%Confidence Intervals (CI) 0.7,2.0) and HTPs (MD=0.8, 95%CI 0.1,1.5) reported stronger smoker identities than those who used NVPs. Compared with smokers, HTP/NVP users had lower cravings for cigarettes (MD=3.0, 95%CI 1.6,4.3; MD=3.1, 95%CI 1.9,4.3, respectively), and higher intention to stop product use (MD=-0.8, 95%CI -1.7,-0.01; MD=-1.2, 95%CI -2.0,-0.3, respectively). People using HTPs or NVPs reported similar perceived product satisfaction (HTP:M=3.4, 95%CI 2.8,3.9; NVP:M=3.0, 95%CI 2.5,3.5), efficacy for smoking cessation (HTP:M=4.5, 95%CI 4.2,4.9; NVP:M=4.6, 95%CI 4.3,4.9) and safety (HTP:M=2.1, 95%CI 2.0,2.2; NVP:M=2.0, 95%CI 1.8,2.1). HTP users reported greater perceived addictiveness than NVPs (MD=0.3, 95%CI 0.2,0.6). Conclusions: HTP and NVP users perceived products to be similarly acceptable and effective suggesting that HTPs, like NVPs, may support smoking cessation. However, since HTP use appears to maintain a stronger smoker identity and perceived addiction, this may suggest a more limited role of HTP for a permanent transition away from cigarettes

Epistasis between the MHC and the RCAα block in primary Sjögren syndrome

ObjectiveThe RCA alpha block (Regulators of Complement Activation, 1q32) contains critical complement regulatory genes such as CR1 and MCP. This study examined RCA alpha block haplotype associations with both disease susceptibility and diversification of the anti-Ro/La autoantibody response in primary Sjögren syndrome (pSS).Methods115 patients with pSS and 98 controls were included in the study. 93 of 109 (85%) of the patients with pSS were seropositive for Ro/La autoantibodies. The Genomic Matching Technique (GMT) was used to define RCA alpha block ancestral haplotypes (AH).ResultsRCA alpha block haplotypes, AH1 and AH3, were both associated with autoantibody-positive pSS (p = 0.0003). Autoantibody associations with both HLA DR3 and DR15 have been previously defined. There was an epistatic interaction (p = 0.023) between RCA alpha AH1 and HLA DR3, and this genotypic combination was present in 48% of autoantibody-positive patients with pSS compared with 8% of controls. This epistasis is most simply attributable to an interaction between C4 and its receptor, CR1, encoded within the RCA alpha block. Both DR3 and a relative C4 deficiency are carried on the major histocompatibility complex 8.1 ancestral haplotype. Only four of 92 (4%) autoantibody-positive patients with pSS did not carry any risk RCA alpha or HLA haplotype, compared with 36 of 96 (38%) controls, and there were differences in haplotype frequencies within autoantibody subsets of pSS.ConclusionsNormal population variation in the RCA alpha block, in addition to the major histocompatibility complex, contributes genetic susceptibility to systemic autoimmune disease and the autoantibody response. This finding provides evidence for the role of regulation of complement activation in disease pathogenesis.S. Lester, C. McLure, J. Williamson, P. Bardy, M. Rischmueller, R. L. Dawkin

Extended haplodiploidy hypothesis

Evolution of altruistic behavior was a hurdle for the logic of Darwinian evolution. Soon after Hamilton formalized the concept of inclusive fitness, which explains how altruism can evolve, he suggested that the high sororal relatedness brought by haplodiploidy could be why Hymenopterans have a high prevalence in eusocial species, and why helpers in Hymenoptera are always female. Later it was noted that in order to capitalize on the high sororal relatedness, helpers would need to direct help toward sisters, and this would bias the population sex ratio. Under a 1:3 males:females sex ratio, the inclusive fitness valuation a female places on her sister, brother, and an own offspring are equalapparently removing the benefit of helping over independent reproduction. Based on this argumentation, haplodiploidy hypothesis has been considered a red herring. However, here we show that when population sex ratio, cost of altruism, and population growth rate are considered together, haplodiploidy does promote female helping even with female-biased sex ratio, due the lowered cost of altruism in such populations. Our analysis highlights the need to re-evaluate the role of haplodiploidy in the evolution of helping, and the importance of fully exploring the model assumptions when comparing interactions of population sex ratios and social behaviors.Peer reviewe

Clinical investigation of an outbreak of alveolitis and asthma in a car engine manufacturing plant

Background Exposure to metal working fluid (MWF) has been associated with outbreaks of EAA in the US, with bacterial contamination of MWF being a possible cause, but was uncommon in the UK. Twelve workers developed extrinsic allergic alveolitis (EAA) in a car engine manufacturing plant in the UK, presenting clinically between December 2003 and May 2004. This paper reports the subsequent epidemiological investigation of the whole workforce. This had three aims:- • To measure the extent of the outbreak by identifying other workers who may have developed EAA or other work-related respiratory diseases. • To provide case-detection so that those affected can be treated. • To provide epidemiological data to identify the cause of the outbreak. Methods The outbreak was investigated in a three-phase cross-sectional survey of the workforce. Phase I A respiratory screening questionnaire was completed by 808/836 workers (96.7%) in May 2004. Phase II 481 employees with at least one respiratory symptom on screening and 50 asymptomatic controls were invited for investigation at the factory in June 2004. This included a questionnaire, spirometry and clinical opinion. 454/481(94.4%) responded along with 48/50(96%) controls. Workers were identified who needed further investigation and serial measurements of peak expiratory flow (PEF). Phase III 162 employees were seen at the Birmingham Occupational Lung Disease clinic. 198 employees returned PEF records, including 141 of the 162 who attended for clinical investigation. Case definitions for diagnoses were agreed. Results 87 workers (10.4% of workforce) met case definitions for occupational lung disease, comprising EAA(19), occupational asthma(74) and humidifier fever(7). 12 workers had more than one diagnosis. The peak onset of work-related breathlessness was Spring 2003. The proportion of workers affected was higher for those using metal working fluid (MWF) from a large sump(27.3%) compared with working all over the manufacturing area (7.9%) (OR=4.39,p<0.001). Two workers had positive specific provocation tests to the used but not the unused MWF solution. Conclusions Extensive investigation of the outbreak of EAA detected a large number of affected workers, not only with EAA but also occupational asthma. This is the largest reported outbreak in Europe. Mist from used MWF is the likely cause. In workplaces using MWF, there is a need to carry out risk assessments, to monitor and maintain fluid quality, to control mist and to carry out respiratory health surveillance