73 research outputs found
Method for the rapid temperature correction of a transmission in an inhomogeneous atmosphere
The value of the transmission function in a heterogeneous atmosphere is determined by iterative correction of values in particular layers. The iterative equation and a set of absolute values of errors is presented in two tables
A critical analysis of the potential for EU Common Agricultural Policy measures to support wild pollinators on farmland
1. Agricultural intensification and associated loss of high‐quality habitats are key drivers of insect pollinator declines. With the aim of decreasing the environmental impact of agriculture, the 2014 EU Common Agricultural Policy (CAP) defined a set of habitat and landscape features (Ecological Focus Areas: EFAs) farmers could select from as a requirement to receive basic farm payments. To inform the post‐2020 CAP, we performed a European‐scale evaluation to determine how different EFA options vary in their potential to support insect pollinators under standard and pollinator‐friendly management, as well as the extent of farmer uptake.
2. A structured Delphi elicitation process engaged 22 experts from 18 European countries to evaluate EFAs options. By considering life cycle requirements of key pollinating taxa (i.e. bumble bees, solitary bees and hoverflies), each option was evaluated for its potential to provide forage, bee nesting sites and hoverfly larval resources.
3. EFA options varied substantially in the resources they were perceived to provide and their effectiveness varied geographically and temporally. For example, field margins provide relatively good forage throughout the season in Southern and Eastern Europe but lacked early‐season forage in Northern and Western Europe. Under standard management, no single EFA option achieved high scores across resource categories and a scarcity of late season forage was perceived.
4. Experts identified substantial opportunities to improve habitat quality by adopting pollinator‐friendly management. Improving management alone was, however, unlikely to ensure that all pollinator resource requirements were met. Our analyses suggest that a combination of poor management, differences in the inherent pollinator habitat quality and uptake bias towards catch crops and nitrogen‐fixing crops severely limit the potential of EFAs to support pollinators in European agricultural landscapes.
5. Policy Implications. To conserve pollinators and help protect pollination services, our expert elicitation highlights the need to create a variety of interconnected, well‐managed habitats that complement each other in the resources they offer. To achieve this the Common Agricultural Policy post‐2020 should take a holistic view to implementation that integrates the different delivery vehicles aimed at protecting biodiversity (e.g. enhanced conditionality, eco‐schemes and agri‐environment and climate measures). To improve habitat quality we recommend an effective monitoring framework with target‐orientated indicators and to facilitate the spatial targeting of options collaboration between land managers should be incentivised
Optical generation of matter qubit graph states
We present a scheme for rapidly entangling matter qubits in order to create
graph states for one-way quantum computing. The qubits can be simple 3-level
systems in separate cavities. Coupling involves only local fields and a static
(unswitched) linear optics network. Fusion of graph state sections occurs with,
in principle, zero probability of damaging the nascent graph state. We avoid
the finite thresholds of other schemes by operating on two entangled pairs, so
that each generates exactly one photon. We do not require the relatively slow
single qubit local flips to be applied during the growth phase: growth of the
graph state can then become a purely optical process. The scheme naturally
generates graph states with vertices of high degree and so is easily able to
construct minimal graph states, with consequent resource savings. The most
efficient approach will be to create new graph state edges even as qubits
elsewhere are measured, in a `just in time' approach. An error analysis
indicates that the scheme is relatively robust against imperfections in the
apparatus.Comment: 10 pages in 2 column format, includes 4 figures. Problems with
figures resolve
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Linking farmer and beekeeper preferences with ecological knowledge to improve crop pollination
1. Pollination by insects is a key input into many crops, with managed honeybees often being hired to support pollination services. Despite substantial research into pollination management, no European studies have yet explored how and why farmers managed pollination services and few have explored why beekeepers use certain crops.
2. Using paired surveys of beekeepers and farmers in 10 European countries, this study examines beekeeper and farmer perceptions and motivations surrounding crop pollination.
3. Almost half of the farmers surveyed believed they had pollination service deficits in one or more of their crops.
4. Less than a third of farmers hired managed pollinators, however most undertook at least one form of agri-environment management known to benefit pollinators, although few did so to promote pollinators.
5. Beekeepers were ambivalent towards many mass flowering crops, with some beekeepers using crops for their honey that other beekeepers avoid because of perceived pesticide risks.
6. The findings highlight a number of largely overlooked knowledge gaps that will affect knowledge exchange and co-operation between the two groups
Narrowband Biphotons: Generation, Manipulation, and Applications
In this chapter, we review recent advances in generating narrowband biphotons
with long coherence time using spontaneous parametric interaction in monolithic
cavity with cluster effect as well as in cold atoms with electromagnetically
induced transparency. Engineering and manipulating the temporal waveforms of
these long biphotons provide efficient means for controlling light-matter
quantum interaction at the single-photon level. We also review recent
experiments using temporally long biphotons and single photons.Comment: to appear as a book chapter in a compilation "Engineering the
Atom-Photon Interaction" published by Springer in 2015, edited by A.
Predojevic and M. W. Mitchel
High Speed and High Efficiency Travelling Wave Single-Photon Detectors Embedded in Nanophotonic Circuits
Ultrafast, high quantum efficiency single photon detectors are among the most
sought-after elements in modern quantum optics and quantum communication. High
photon detection efficiency is essential for scalable measurement-based quantum
computation, quantum key distribution, and loophole-free Bell experiments.
However, imperfect modal matching and finite photon absorption rates have
usually limited the maximum attainable detection efficiency of single photon
detectors. Here we demonstrate a superconducting nanowire detector atop
nanophotonic waveguides which allows us to drastically increase the absorption
length for incoming photons. When operating the detectors close to the critical
current we achieve high on-chip single photon detection efficiency up to 91% at
telecom wavelengths, with uncertainty dictated by the variation of the
waveguide photon flux. We also observe remarkably low dark count rates without
significant compromise of detection efficiency. Furthermore, our detectors are
fully embedded in a scalable silicon photonic circuit and provide ultrashort
timing jitter of 18ps. Exploiting this high temporal resolution we demonstrate
ballistic photon transport in silicon ring resonators. The direct
implementation of such a detector with high quantum efficiency, high detection
speed and low jitter time on chip overcomes a major barrier in integrated
quantum photonics
Serum Biomarkers of Myocardial Remodeling and Coronary Dysfunction in Early Stages of Hypertrophic Cardiomyopathy in the Young
National records of 3000 European bee and hoverfly species: A contribution to pollinator conservation
Pollinators play a crucial role in ecosystems globally, ensuring the seed production of most flowering plants. They are threatened by global changes and knowledge of their distribution at the national and continental levels is needed to implement efficient conservation actions, but this knowledge is still fragmented and/or difficult to access. As a step forward, we provide an updated list of around 3000 European bee and hoverfly species, reflecting their current distributional status at the national level (in the form of present, absent, regionally extinct, possibly extinct or non-native). This work was attainable by incorporating both published and unpublished data, as well as knowledge from a large set of taxonomists and ecologists in both groups. After providing the first National species lists for bees and hoverflies for many countries, we examine the current distributional patterns of these species and designate the countries with highest levels of species richness. We also show that many species are recorded in a single European country, highlighting the importance of articulating European and national conservation strategies. Finally, we discuss how the data provided here can be combined with future trait and Red List data to implement research that will further advance pollinator conservation
Current cardiac imaging techniques for detection of left ventricular mass
Estimation of left ventricular (LV) mass has both prognostic and therapeutic value independent of traditional risk factors. Unfortunately, LV mass evaluation has been underestimated in clinical practice. Assessment of LV mass can be performed by a number of imaging modalities. Despite inherent limitations, conventional echocardiography has fundamentally been established as most widely used diagnostic tool. 3-dimensional echocardiography (3DE) is now feasible, fast and accurate for LV mass evaluation. 3DE is also superior to conventional echocardiography in terms of LV mass assessment, especially in patients with abnormal LV geometry. Cardiovascular magnetic resonance (CMR) and cardiovascular computed tomography (CCT) are currently performed for LV mass assessment and also do not depend on cardiac geometry and display 3-dimensional data, as well. Therefore, CMR is being increasingly employed and is at the present standard of reference in the clinical setting. Although each method demonstrates advantages over another, there are also disadvantages to receive attention. Diagnostic accuracy of methods will also be increased with the introduction of more advanced systems. It is also likely that in the coming years new and more accurate diagnostic tests will become available. In particular, CMR and CCT have been intersecting hot topic between cardiology and radiology clinics. Thus, good communication and collaboration between two specialties is required for selection of an appropriate test
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