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Pollination services in the UK: how important are honeybees?
Pollination services are known to provide substantial benefits to human populations and agriculture in particular. Although many species are known to provide pollination services, honeybees (Apis mellifera) are often assumed to provide the majority of these services to agriculture. Using data from a range of secondary sources, this study assesses the importance of insect pollinated crops at regional and national scales and investigates the capacity of honeybees to provide optimal pollination services to UK agriculture. The findings indicate that insect pollinated crops have become increasingly important in UK crop agriculture and, as of 2007, accounted for 20% of UK cropland and 19% of total farmgate crop value. Analysis of honeybee hive numbers indicates that current UK populations are only capable of supplying 34% of pollination service demands even under favourable assumptions, falling from 70% in 1984. In spite of this decline, insect pollinated crop yields have risen by an average of 54% since 1984, casting doubt on long held beliefs that honeybees provide the majority of pollination services. Future land use and crop production patterns may further increase the role of pollination services to UK agriculture, highlighting the importance of measures aimed at maintaining both wild and managed species
Morphing Wings Using Macro Fiber Composites
Macro Fiber Composites (MFC) are smart materials that have one or more properties that can be altered by an external stimulus such as magnetic and electric fields, temperature and pH, in order to meet specific requirements or conditions. Today, smart materials are used in a variety of applications in the aerospace industry, locomotives, and in the medical field to generate better performance for its devices. The objective of this paper is to describe an experiment on morphing a wing using MFCs. The materials needed to achieve this project are illustrated in the experimental setup of this paper. Additionally, the author expects to be able to morph the wing of the aircraft and compare its acquired data to that of a general aircraft to determine which one has the best performance
Suppression of Kelvon-induced decay of quantized vortices in oblate Bose-Einstein Condensates
We study the Kelvin mode excitations on a vortex line in a three-dimensional
trapped Bose-Einstein condensate at finite temperature. Our stochastic
Gross-Pitaevskii simulations show that the activation of these modes can be
suppressed by tightening the confinement along the direction of the vortex
line, leading to a strong suppression in the vortex decay rate as the system
enters a regime of two-dimensional vortex dynamics. As the system approaches
the condensation transition temperature we find that the vortex decay rate is
strongly sensitive to dimensionality and temperature, observing a large
enhancement for quasi-two-dimensional traps. Three-dimensional simulations of
the recent vortex dipole decay experiment of Neely et al. [Phys. Rev. Lett.
104, 160401 (2010)] confirm two-dimensional vortex dynamics, and predict a
dipole lifetime consistent with experimental observations and suppression of
Kelvon-induced vortex decay in highly oblate condensates.Comment: 8 pages, 8 figure
Mean field approaches to the totally asymmetric exclusion process with quenched disorder and large particles
The process of protein synthesis in biological systems resembles a one
dimensional driven lattice gas in which the particles (ribosomes) have spatial
extent, covering more than one lattice site. Realistic, nonuniform gene
sequences lead to quenched disorder in the particle hopping rates. We study the
totally asymmetric exclusion process with large particles and quenched disorder
via several mean field approaches and compare the mean field results with Monte
Carlo simulations. Mean field equations obtained from the literature are found
to be reasonably effective in describing this system. A numerical technique is
developed for computing the particle current rapidly. The mean field approach
is extended to include two-point correlations between adjacent sites. The
two-point results are found to match Monte Carlo simulations more closely
Stratified shear flow instabilities at large Richardson numbers
Numerical simulations of stratified shear flow instabilities are performed in
two dimensions in the Boussinesq limit. The density variation length scale is
chosen to be four times smaller than the velocity variation length scale so
that Holmboe or Kelvin-Helmholtz unstable modes are present depending on the
choice of the global Richardson number Ri. Three different values of Ri were
examined Ri =0.2, 2, 20. The flows for the three examined values are all
unstable due to different modes namely: the Kelvin-Helmholtz mode for Ri=0.2,
the first Holmboe mode for Ri=2, and the second Holmboe mode for Ri=20 that has
been discovered recently and it is the first time that it is examined in the
non-linear stage. It is found that the amplitude of the velocity perturbation
of the second Holmboe mode at the non-linear stage is smaller but comparable to
first Holmboe mode. The increase of the potential energy however due to the
second Holmboe modes is greater than that of the first mode. The
Kelvin-Helmholtz mode is larger by two orders of magnitude in kinetic energy
than the Holmboe modes and about ten times larger in potential energy than the
Holmboe modes. The results in this paper suggest that although mixing is
suppressed at large Richardson numbers it is not negligible, and turbulent
mixing processes in strongly stratified environments can not be excluded.Comment: Submitted to Physics of Fluid
Conversion Prediction Using Multi-task Conditional Attention Networks to Support the Creation of Effective Ad Creative
Accurately predicting conversions in advertisements is generally a
challenging task, because such conversions do not occur frequently. In this
paper, we propose a new framework to support creating high-performing ad
creatives, including the accurate prediction of ad creative text conversions
before delivering to the consumer. The proposed framework includes three key
ideas: multi-task learning, conditional attention, and attention highlighting.
Multi-task learning is an idea for improving the prediction accuracy of
conversion, which predicts clicks and conversions simultaneously, to solve the
difficulty of data imbalance. Furthermore, conditional attention focuses
attention of each ad creative with the consideration of its genre and target
gender, thus improving conversion prediction accuracy. Attention highlighting
visualizes important words and/or phrases based on conditional attention. We
evaluated the proposed framework with actual delivery history data (14,000
creatives displayed more than a certain number of times from Gunosy Inc.), and
confirmed that these ideas improve the prediction performance of conversions,
and visualize noteworthy words according to the creatives' attributes.Comment: 9 pages, 6 figures. Accepted at The 25th ACM SIGKDD Conference on
Knowledge Discovery and Data Mining (KDD 2019) as an applied data science
pape
Perturbative behaviour of a vortex in a trapped Bose-Einstein condensate
We derive a set of equations that describe the shape and behaviour of a
single perturbed vortex line in a Bose-Einstein condensate. Through the use of
a matched asymptotic expansion and a unique coordinate transform a relation for
a vortex's velocity, anywhere along the line, is found in terms of the
trapping, rotation, and distortion of the line at that location. This relation
is then used to find a set of differential equations that give the line's
specific shape and motion. This work corrects a previous similar derivation by
Anatoly A. Svidzinsky and Alexander L. Fetter [Phys. Rev. A \textbf{62}, 063617
(2000)], and enables a comparison with recent numerical results.Comment: 12 pages with 3 figure
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