Optical absorption in the strong coupling limit of Eliashberg theory

We calculate the optical conductivity of superconductors in the strong-coupling limit. In this anomalous limit the typical energy scale is set by the coupling energy, and other energy scales such as the energy of the bosons mediating the attraction are negligibly small. We find a universal frequency dependence of the optical absorption which is dominated by bound states and differs significantly from the weak coupling results. A comparison with absorption spectra of superconductors with enhanced electron-phonon coupling shows that typical features of the strong-coupling limit are already present at intermediate coupling.Comment: 10 pages, revtex, 4 uuencoded figure

RTEL1 contributes to DNA replication and repair and telomere maintenance

Telomere maintenance and DNA repair are important processes that protect the genome against instability. mRtel1, an essential helicase, is a dominant factor setting telomere length in mice. In addition, mRtel1 is involved in DNA double-strand break repair. The role of mRtel1 in telomere maintenance and genome stability is poorly understood. Therefore we used mRtel1-deficient mouse embryonic stem cells to examine the function of mRtel1 in replication, DNA repair, recombination, and telomere maintenance. mRtel1-deficient mouse embryonic stem cells showed sensitivity to a range of DNA-damaging agents, highlighting its role in replication and genome maintenance. Deletion of mRtel1 increased the frequency of sister chromatid exchange events and suppressed gene replacement, demonstrating the involvement of the protein in homologous recombination. mRtel1 localized transiently at telomeres and is needed for efficient telomere replication. Of interest, in the absence of mRtel1, telomeres in embr

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Palynology and palaeoclimatic implications of two Holocene sequences from southwestern Australia

Results from two palynological investigations of Holocene lake and swamp deposits from southwestern Western Australia are presented. These are used to assess the validity of the existing palaeoclimatic evidence for Holocene climates, which is contradictory. The Boggy Lake sequence from the far southwest of Western Australia shows that, while vegetation changes have taken place over the last ca. 4500 years, these cannot be attributed to climatic change. Palaeoecological interpretations of earlier work at the site are shown to have an insecure basis. The Loch McNess Swamp sequence from further north shows only minor vegetation changes since ca. 9000 yr B.P. which cannot be attributed with certainty to climatic causes. The investigations do not support earlier claims of Mid-Holocene climates wetter than present or of an extensive arid phase in the Mid- to Late-Holocene

Eucalyptus (Myrtaceae) pollen and its potential role in investigations of Holocene environments in southwestern Australia

This study investigated the potential for using suites of pollen morphological characteristics to identify pollen of Eucalyptus (Myrtaceae) to species in modern and fossil material. Characteristics were examined in the modern pollen from nine species of Eucalyptus that occur in an area around Walpole, on the south coast of southwestern Australia. Success was achieved in separating the modern pollen into defined pollen types. These character suites were then applied to fossil Eucalyptus pollen in a nearby Holocene sequence, Boggy Lake, to assess their usefulness in distinguishing fossil pollen into types. Considerable success was achieved with this, although up to 50% of the pollen grains could not be allocated to the pollen types for a variety of reasons. However, the study demonstrated that the fossil records of Eucalyptus pollen are potentially more environmentally informative than has previously been thought, at least or Holocene studies in this region. The use of suites of characters nay be applicable to the identification of Eucalyptus species elsewhere, and also to other genera within the Myrtaceae

Cluster observations of ELF/VLF signals generated by modulated heating of the lower ionosphere with the HAARP HF transmitter

It is now well known that amplitude modulated HF transmissions into the ionosphere can be used to generate ELF/VLF signals using the so-called "electrojet antenna". Although most observations of the generated ELF/VLF signals have been made on the ground, several low and high-altitude satellite observations have also been reported (James et al., 1990). One of the important unknowns in the physics of ELF/VLF wave generation by ionospheric heating is the volume of the magnetosphere illuminated by the ELF/VLF waves. In an attempt to investigate this question further, ground-satellite conjunction experiments have recently been conducted using the four Cluster satellites and the HF heater of the High-Frequency Active Auroral Research Program (HAARP) facility in Gakona, Alaska. Being located on largely closed field lines at L≈4.9, HAARP is currently also being used for ground-to-ground type of ELF/VLF wave-injection experiments, and will be increasingly used for this purpose as it is now being upgraded for higher power operation. In this paper, we describe the HAARP installation and present recent results of the HAARP-Cluster experiments. We give an overview of the detected ELF/VLF signals at Cluster, and a possible explanation of the spectral signature detected, as well as the determination of the location of the point of injection of the HAARP ELF/VLF signals into the magnetosphere using ray tracing