239 research outputs found

    Incremental motion drive system Patent

    Get PDF
    Incremental motion drive system applied to interferometer component

    Motion drive system is accurately controlled in the 1-micron range

    Get PDF
    Motion drive system has been developed for use with interferometers where accurate control of minuscule distance in the 1-micron range is of prime importance. The drive system is applicable to any device that requires extremely accurate positioning control

    An Experiment on Impulse Excitation

    Get PDF
    n/

    VICAR-DIGITAL image processing system

    Get PDF
    Computer program corrects various photometic, geometric and frequency response distortions in pictures. The program converts pictures to a number of elements, with each elements optical density quantized to a numerical value. The translated picture is recorded on magnetic tape in digital form for subsequent processing and enhancement by computer

    Impacts of climate change on national biodiversity population trends

    Get PDF
    Lepidoptera are sensitive to climate change, with documented impacts on their phenology, distribution and communities. However, there remains considerable uncertainty over which species are most vulnerable, and which have been most affected so far. To address this, we analyse 35-year UK or English population trends of 55 butterfly and 265 moth species to model the impacts of variation in temperature and precipitation upon population growth rates. We identify the weather variables and periods that species are most sensitive to, the long-term impacts of climate change, and the characteristics of species which show the greatest responses. Positive impacts of summer temperature on both butterflies and moths were partly offset by negative impacts of temperature in other seasons, particularly winter. Precipitation tended to have negative impacts on population growth rates, particularly for moths. Annual population fluctuations were strongly driven by inter-annual variation in weather conditions. Over 40% of a significant decline in mean moth abundance from the 1990s to 2000s was consistent with a weather-driven decline predicted by our models, which also explained up to 19% of the decadal variation in abundance between species. Species overwintering as larvae and multivoltine species were most sensitive to the effects of weather, whilst southerly-distributed species, species associated with woodland and unimproved grassland habitats, and pest species, showed the most positive long-term responses to climate change. Combined, these results show how climate change is already having significant impacts on the abundance of particular butterfly and moth species, with likely future consequences for ecosystem function and services

    Conducting robust ecological analyses with climate data

    Get PDF
    Although the number of studies discerning the impact of climate change on ecological systems continues to increase, there has been relatively little sharing of the lessons learnt when accumulating this evidence. At a recent workshop entitled ‘Using climate data in ecological research’ held at the UK Met Office, ecologists and climate scientists came together to discuss the robust analysis of climate data in ecology. The discussions identified three common pitfalls encountered by ecologists: 1) selection of inappropriate spatial resolutions for analysis; 2) improper use of publically available data or code; and 3) insufficient representation of the uncertainties behind the adopted approach. Here, we discuss how these pitfalls can be avoided, before suggesting ways that both ecology and climate science can move forward. Our main recommendation is that ecologists and climate scientists collaborate more closely, on grant proposals and scientific publications, and informally through online media and workshops. More sharing of data and code (e.g. via online repositories), lessons and guidance would help to reconcile differing approaches to the robust handling of data. We call on ecologists to think critically about which aspects of the climate are relevant to their study system, and to acknowledge and actively explore uncertainty in all types of climate data. And we call on climate scientists to make simple estimates of uncertainty available to the wider research community. Through steps such as these, we will improve our ability to robustly attribute observed ecological changes to climate or other factors, while providing the sort of influential, comprehensive analyses that efforts to mitigate and adapt to climate change so urgently require
    • …
    corecore