Tunable reflection minima of nanostructured antireflective surfaces

Broadband antireflection schemes for silicon surfaces based on the moth-eye principle and comprising arrays of subwavelength-scale pillars are applicable to solar cells, photodetectors, and stealth technologies and can exhibit very low reflectances. We show that rigorous coupled wave analysis can be used to accurately model the intricate reflectance behavior of these surfaces and so can be used to explore the effects of variations in pillar height, period, and shape. Low reflectance regions are identified, the extent of which are determined by the shape of the pillars. The wavelengths over which these low reflectance regions operate can be shifted by altering the period of the array. Thus the subtle features of the reflectance spectrum of a moth-eye array can be tailored for optimum performance for the input spectrum of a specific application

FishBase: the on-line answer to ichthyological issues

FishBase was initiated by Daniel Pauly and Rainer Froese as an electronic fact sheets database for the economically most important fish species. From 1987 onwards FishBase was developed at the WorldFish Center (former ICLARM), and subsequently financed by the European Commission between 1989 and 2000. Since 2001, FishBase is supported by a consortium, including the WorldFish Center (Malaysia), FAO (Italy), The Royal Museum for Central Africa (Belgium), the Natural History Museums of Paris (France) and Stockholm (Sweden), the Universities of Kiel (Germany), British Columbia (Canada) and Thessaloniki (Greece), and the Chinese Academy of Fishery Sciences (China). At present FishBase is the largest on-line encyclopaedia on fishes, with about 20 - 25 million hits per month.Information on more than 30,000 fish species is available through the FishBase portal (www.fishbase.org) or one of its 6 mirror-sites, including data on the taxonomic position, distribution, morphology and ecology, as well as numerous aspects of aquaculture and fisheries biology. Information is based on scientific publications or provided by experts. Many deep links are provided to other relevant websites such as those of the IUCN (conservation) and GenBank (genetics). The Royal Museum for Central Africa is responsible for the validation and updating of the information on all African fresh- and brackish water fishes and developed in 2007 a portal for the African inland fishes (www.fishbaseforafrica.org).FishBase contains a lot of applications for fish and fisheries scientists, such as tools for fish identification, biogeographical modelling, construction and analysis of trophic pyramids, analysis of fishery and aquaculture statistics, diagnosis of fish diseases, etc. Some of these have already proved their importance to support concepts like ‘fishing down food webs’ (Pauly et al., 1998)

The circumbinary disk of HD 98800B: Evidence for disk warping

The quadruple young stellar system HD 98800 consists of two spectroscopic binary pairs with a circumbinary disk around the B component. Recent work by Boden and collaborators using infrared interferometry and radial velocity data resulted in a determination of the physical orbit for HD 98800B. We use the resulting inclination of the binary and the measured extinction toward the B component stars to constrain the distribution of circumbinary material. Although a standard optically and geometrically thick disk model can reproduce the spectral energy distribution, it cannot account for the observed extinction if the binary and the disk are coplanar. We next constructed a dynamical model to investigate the influence of the A component, which is not in the Ba‐Bb orbital plane, on the B disk. We find that these interactions have a substantial impact on the inclination of the B circumbinary disk with respect to the Ba‐Bb orbital plane. The resulting warp would be sufficient to place material into the line of sight and the noncoplanar disk orientation may also cause the upper layers of the disk to intersect the line of sight if the disk is geometrically thick. These simulations also support that the dynamics of the Ba‐Bb orbit clear the inner region to a radius of~3 AU. We then discuss whether the somewhat unusual properties of the HD 98800B disk are consistent with material remnant from the star formation process or with more recent creation by collisions from larger bodies

Some Empirical Criteria for Attributing Creativity to a Computer Program

Peer reviewedPostprin

A risk assessment of equine piroplasmosis entry, exposure and consequences in the UK

Background: Equine piroplasmosis (EP) is currently not endemic in the UK, despite a lack of formal surveillance and the presence of carrier horses in the equine population. Pathogen establishment would have significant welfare and economic impacts on the national equine industry, but the disease is often overlooked by UK practitioners. Objectives: To assess the risk of disease entry, exposure and consequences to the UK equine population. Study design: Qualitative risk assessment. Methods: A qualitative risk assessment was constructed utilising the current World Organisation for Animal Health (OIE) published framework for importation risk assessment, assessing the key areas of disease entry, exposure and consequences to the UK equine population. Results: The overall risk of EP entry to the UK via importation of infected equidae with acute disease is very low but considered medium with subclinical carrier animals. Entry via importation of ticks or the importation of blood is considered very low. The risk of EP exposure to susceptible equidae in the UK is considered low by the infection routes of tick-bites, contaminated needles and contaminated blood, but very high via transplacental transfer. However, the consequences of EP endemic establishment are considered of high significance to the UK equine industry. Main limitations: A lack of available numerical data for events and variables in disease import risk meant a qualitative assessment was the most practical method for this scenario. Conclusions: This risk assessment highlights that EP positive animals are able to enter and are currently present in the UK, and that conditions do exist that could allow forward transmission of the disease. It has highlighted a gap in existing policy where the UK falls behind OIE guidelines and has suggested steps to correct this discrepancy and improve national biosecurity