The tandem radical route to indole alkaloids: an unusual rearrangement reaction

Cyclisation of the precursor 6 under standard radical conditions yields the tetracyclic structure 7 which represents the core of a number of indole alkaloids along with the novel tetracycle 13

Hot Electrons and Cold Photons: Galaxy Clusters and the Sunyaev-Zel'dovich Effect

The hot gas in clusters of galaxies emits thermal bremsstrahlung emission that can be probed directly through measurements in the X-ray band with satellites like ROSAT and ASCA. Another probe of this gas comes from its effect on the cosmic microwave background radiation (CMBR): the hot cluster electrons inverse Compton scatter the CMBR photons and thereby distort the background radiation from its blackbody spectral form. In the last few years, the development of sensitive new instruments for measuring this distortion, called the Sunyaev-Zel'dovich (SZ) effect, has sparked a revolution in the field. Current radio interferometric arrays can now detect and map the SZ effect in even distant (z ~ 1) clusters. It is well known that one of the purposes of conducting such measurements is to determine the Hubble constant. In this review I report on the progress that has been made in this area, quote the current best estimate of Ho from the SZ effect of 8 galaxy clusters (44 - 64 km/s/Mpc +/- 17%), discuss important systematic uncertainties, and highlight what else has been learned about galaxy clusters from these investigations.Comment: 4 pages, including 2 postscript figs, LaTeX. To appear in the proceedings of IAU Symposium 188 "The Hot Universe" (held August 26-30, 1997, Kyoto, Japan

Robust study design is as important on the social as it is on the ecological side of applied ecological research

1. The effective management of natural systems often requires resource users to change their behaviour. This has led to many applied ecologists using research tools developed by social scientists. This comes with challenges as ecologists often lack relevant disciplinary training. 2. Using an example from the current issue of Journal of Applied Ecology that investigated how conservation interventions influenced conservation outcomes, we discuss the challenges of conducting interdisciplinary science. We illustrate our points using examples from research investigating the role of law enforcement and outreach activities in limiting illegal poaching and the application of the theory of planned behaviour to conservation. 3. Synthesis and applications. Interdisciplinary research requires equal rigour to be applied to ecological and social aspects. Researchers with a natural science background need to access expertise and training in the principles of social science research design and methodology, in order to permit a more balanced interdisciplinary understanding of social–ecological system

Network effects in a human capital based economic growth model

We revisit a recently introduced agent model[ACS {\bf 11}, 99 (2008)], where economic growth is a consequence of education (human capital formation) and innovation, and investigate the influence of the agents' social network, both on an agent's decision to pursue education and on the output of new ideas. Regular and random networks are considered. The results are compared with the predictions of a mean field (representative agent) model.Comment: to appear in Physica

Recent developments in near-infrared spectroscopy (NIRS) for the assessment of local skeletal muscle microvascular function and capacity to utilise oxygen

PURPOSE OF REVIEW: Continuous wave near infrared spectroscopy (CW NIRS) provides non-invasive technology to measure relative changes in oxy- and deoxy-haemoglobin in a dynamic environment. This allows determination of local skeletal muscle O2 saturation, muscle oxygen consumption (View the MathML source) and blood flow. This article provides a brief overview of the use of CW NIRS to measure exercise-limiting factors in skeletal muscle. RECENT FINDINGS: NIRS parameters that measure O2 delivery and capacity to utilise O2 in the muscle have been developed based on response to physiological interventions and exercise. NIRS has good reproducibility and agreement with gold standard techniques and can be used in clinical populations where muscle oxidative capacity or oxygen delivery (or both) are impaired. CW NIRS has limitations including: the unknown contribution of myoglobin to the overall signals, the impact of adipose tissue thickness, skin perfusion during exercise, and variations in skin pigmentation. These, in the main, can be circumvented through appropriate study design or measurement of absolute tissue saturation. SUMMARY: CW NIRS can assess skeletal muscle O2 delivery and utilisation without the use of expensive or invasive procedures and is useable in large population-based samples, including older adults

Expressive vocabulary predicts non-verbal executive function: a 2-year longitudinal study of deaf and hearing children

Numerous studies suggest an association between language and executive function (EF), but evidence of a developmental relationship remains inconclusive. Data were collected from 75 deaf/hard-of-hearing (DHH) children and 82 hearing age-matched controls. Children were 6-11 years old at first time of testing, and completed a battery of nonverbal EF tasks and a test of expressive vocabulary. These tasks were completed again two years later. Both groups improved their scores on all tasks over this period. DHH children performed significantly less well than hearing peers on some EF tasks and the vocabulary test at both time points. Cross-lagged panel models showed that vocabulary at Time 1 predicted change in EF scores for both DHH and hearing children but not the reverse

Clinically insignificant association between anterior knee pain and patellofemoral lesions which are found incidentally.

Patellofemoral chondral lesions are frequently identified incidentally during the arthroscopic treatment of other knee pathologies. A role has been described for arthroscopic debridement of such lesions when symptoms are known to originate from pathology of the patellofemoral joint. However, it remains unclear how to manage lesions which are found incidentally whilst tackling other pathologies. The purpose of this study was to establish the strength of association between anterior knee pain and patellofemoral lesions identified incidentally in a typical arthroscopic population. A consecutive series of patients undergoing arthroscopy for a range of standard indications formed the basis of this cross section study. We excluded those with patellofemoral conditions in order to identify patellofemoral lesions which were solely incidental. Pre-operative assessments were performed on 64 patients, where anterior knee pain was sought by three methods: an annotated photographic knee pain map (PKPM), patient indication with one finger and by palpated tenderness. A single surgeon, who was blinded to previous recordings, performed standard arthroscopies and recorded patellofemoral lesions. Statistical correlations were performed to identify the association magnitude. Associations were identified between incidental patellofemoral lesions and tenderness palpated on the medial patella (P=0.007, χ2=0.32) and the quadriceps tendon (P=0.029, χ2=0.26), but these associations were at best fair, which could be interpreted as clinically insignificant. In which case incidental patellofemoral lesions are not necessarily associated with anterior knee pain, we suggest that they could be left alone. This recommendation is only applicable to patellofemoral lesions which are found incidentally whilst addressing other pathology

Tirisporella gen. nov., an ascomycete from the mangrove palm Nypa fruticans

Tirisporella beccariana comb.nov. is redescribed from decomposing leaf petiole (or rachis) bases of Nypa fruticans recently collected in Malaysia and the Philippiines. The superficial ascomata bear bitunicate asci with (3-)5(-7)-septate ascospores that are brown and verrucose, except for the prominent hyaline basal cell, and furnished with a distinctive apical appendage that arises from the spore wall. Te ultrastructure of the fungus is contrasted with that of species of Corollospora and Corallicola, with particular reference to the mode of ascospore appendage formation. The species was originally described from a Sarawak collection as Sphaeria becariana and later transferred to Melanomma and given the new name Melanomma cesatianum. Gibberidea nipae is a synonym. The recent collections were compared with type specimens. The fungus is not properly placed in Melanomma or Gibberidea or other known genera and a new genus Tiriporella is described.published_or_final_versio

Grain refinement in a AlZnMgCuTi alloy by intensive melt shearing: A multi-step nucleation mechanism

This is a post-print version of the article. Copyright @ 2010 Elsevier B.V.Direct chill (DC) cast ingots of wrought Al alloys conventionally require the deliberate addition of a grain refiner to provide a uniform as-cast microstructure for the optimisation of both mechanical properties and processability. Grain refiner additions have been in widespread industrial use for more than half a century. Intensive melt shearing can provide grain refinement without the need for a specific grain refiner addition for both magnesium and aluminium based alloys. In this paper we present experimental evidence of the grain refinement in an experimental wrought aluminium alloy achieved by intensive melt shearing in the liquid state prior to solidification. The mechanisms for high shear induced grain refinement are correlated with the evolution of oxides in alloys. The oxides present in liquid aluminium alloys, normally as oxide films and clusters, can be effectively dispersed by intensive shearing and then provide effective sites for the heterogeneous nucleation of Al3Ti phase. As a result, Al3Ti particles with a narrow size distribution and hence improved efficiency as active nucleation sites of alpha-aluminium grains are responsible for the achieved significant grain refinement. This is termed a multi-step nucleation mechanism.Funding was obtained from the EPRSC