928 research outputs found
SpotCard: an optical mark recognition tool to improve field data collection speed and accuracy.
BACKGROUND: When taking photographs of plants in the field, it is often necessary to record additional information such as sample number, biological replicate number and subspecies. Manual methods of recording such information are slow, often involve laborious transcription from hand-written notes or the need to have a laptop or tablet on site, and present a risk by separating written data capture from image capture. Existing tools for field data capture focus on recording information rather than capturing pictures of plants. RESULTS: We present SpotCard, a tool comprising two macros. The first can be used to create a template for small, reusable cards for use when photographing plants. Information can be encoded on these cards in a human- and machine-readable form, allowing the user to swiftly make annotations before taking the photograph. The second part of the tool automatically reads the annotations from the image and tabulates them in a CSV file, along with picture date, time and GPS coordinates. The SpotCard also provides a convenient scale bar and coordinate location within the image for the flower itself, enabling automated measurement of floral traits such as area and perimeter. CONCLUSIONS: This tool is shown to read annotations with a high degree of accuracy and at a speed greatly faster than manual transcription. It includes the ability to read the date and time of the photograph, as well as GPS location. It is an open-source ImageJ/Fiji macro and is available online. Its use requires no knowledge of the ImageJ macro coding language, and it is therefore well suited to all researchers taking pictures in the field
The mechanics of nectar offloading in the bumblebee Bombus terrestris and implications for optimal concentrations during nectar foraging.
Nectar is a common reward provided by plants for pollinators. More concentrated nectar is more rewarding, but also more viscous, and hence more time-consuming to drink. Consequently, theory predicts an optimum concentration for maximizing energy uptake rate, dependent on the mechanics of feeding. For social pollinators such as bumblebees, another important but little-studied aspect of foraging is nectar offloading upon return to the nest. Studying the bumblebee Bombus terrestris, we found that the relationship between viscosity (”) and volumetric transfer rates (Q) of sucrose solutions differed between drinking and offloading. For drinking, Q â ”-0.180, in good agreement with previous work. Although offloading was quicker than drinking, offloading rate decreased faster with viscosity, with Q â ”-0.502, consistent with constraints imposed by fluid flow through a tube. The difference in mechanics between drinking and offloading nectar leads to a conflict in the optimum concentration for maximizing energy transfer rates. Building a model of foraging energetics, we show that including offloading lowers the maximum rate of energy return to the nest and reduces the concentration which maximizes this rate by around 3%. Using our model, we show that published values of preferred nectar sugar concentrations suggest that bumblebees maximize the overall energy return rather than the instantaneous energy uptake during drinking.This work was supported by a Biotechnology and Biological Sciences Research Council PhD Studentship under grant BB/J014540/1 to J.G.P
Gaussian process inference approximation for indoor pedestrian localisation
Clutter has a complex effect on radio propagation, and limits the effect-
iveness of deterministic methods in wireless indoor positioning. In
contrast, a Gaussian process (
GP
) can be used to learn the spatially
correlated measurement error directly from training samples, and build
a representation from which a position can be inferred. A method of
exploiting
GP
inference to obtain measurement predictions from
within a pose graph optimisation framework is presented. However,
GP
inference has a run-time complexity of
O
(
N
3
) in the number of train-
ing samples
N
, which precludes it from being called in each optimiser
iteration. The novel contributions of this work are a method for building
an approximate
GP
inference map and an
O
(1) bi-cubic interpolation
strategy for sampling this map during optimisation. Using inertial,
magnetic, signal strength and time-of-
fl
ight measurements between
four anchors and a single mobile sensor, it is shown empirically that
the presented approach leads to decimetre precision indoor pedestrian
localisatio
A simply connected surface of general type with p_g=0 and K^2=2
In this paper we construct a simply connected, minimal, complex surface of
general type with p_g=0 and K^2=2 using a rational blow-down surgery and
Q-Gorenstein smoothing theory.Comment: 19 pages, 6 figures. To appear in Inventiones Mathematica
Equipping future teachers with innovative strategies that increase physical activity in the classroom : A hybrid implementation trial across three Australian universities
Introduction: TransformEd targets initial teacher education (ITE) to equip future teachers with innovative strategies that increase physical activity in the Primary school classroom.
Methods: This hybrid implementation-effectiveness trial investigated the effects of the TransformEd program when embedded in ITE degrees at two Australian universities (University 1 Single Unit offering; University 2 Dual Unit offering) over a 12-week period, on pre-service teachersâ perceived competence, confidence, and willingness to deliver active pedagogies, in comparison with a third âusual practiceâ control university.
Results: There was a favourable intervention effect on the total teacher perceptions score among pre-service teachers in University 1 compared to the control group pre-service teachers. Further, there was a significant intervention effect on reduced perceived barriers to active strategies in University 1, and a significant increase in perceived effects of active strategies on Primary school student outcomes in University 2. Qualitative data suggested the program strengthened the connection between theory and practice (i.e., how pre-service teachers are educated in university and the way they teach in Primary schools). The program was motivating to both lecturers and pre-service teachers, resulted in them reflecting on their own teaching practice, and helped with pre-service teacher engagement.
Discussion: Recommendations for improvement included stronger and more explicit alignment with the Australian Professional Standards for Teachers
Thermal activation between Landau levels in the organic superconductor -(BEDT-TTF)SFCHCFSO
We show that Shubnikov-de Haas oscillations in the interlayer resistivity of
the organic superconductor -(BEDT-TTF)SF
CHCFSO become very pronounced in magnetic fields ~60~T.
The conductivity minima exhibit thermally-activated behaviour that can be
explained simply by the presence of a Landau gap, with the
quasi-one-dimensional Fermi surface sheets contributing negligibly to the
conductivity. This observation, together with complete suppression of chemical
potential oscillations, is consistent with an incommensurate nesting
instability of the quasi-one-dimensional sheets.Comment: 6 pages, 4 figure
Magnetic fields and accretion flows on the classical T Tauri star V2129 Oph
From observations collected with the ESPaDOnS spectropolarimeter, we report
the discovery of magnetic fields at the surface of the mildly accreting
classical T Tauri star V2129 Oph. Zeeman signatures are detected, both in
photospheric lines and in the emission lines formed at the base of the
accretion funnels linking the disc to the protostar, and monitored over the
whole rotation cycle of V2129 Oph. We observe that rotational modulation
dominates the temporal variations of both unpolarized and circularly polarized
line profiles. We reconstruct the large-scale magnetic topology at the surface
of V2129 Oph from both sets of Zeeman signatures simultaneously. We find it to
be rather complex, with a dominant octupolar component and a weak dipole of
strengths 1.2 and 0.35 kG, respectively, both slightly tilted with respect to
the rotation axis. The large-scale field is anchored in a pair of 2-kG unipolar
radial field spots located at high latitudes and coinciding with cool dark
polar spots at photospheric level. This large-scale field geometry is unusually
complex compared to those of non-accreting cool active subgiants with moderate
rotation rates. As an illustration, we provide a first attempt at modelling the
magnetospheric topology and accretion funnels of V2129 Oph using field
extrapolation. We find that the magnetosphere of V2129 Oph must extend to about
7R* to ensure that the footpoints of accretion funnels coincide with the
high-latitude accretion spots on the stellar surface. It suggests that the
stellar magnetic field succeeds in coupling to the accretion disc as far out as
the corotation radius, and could possibly explain the slow rotation of V2129
Oph. The magnetospheric geometry we derive produces X-ray coronal fluxes
typical of those observed in cTTSs.Comment: MNRAS, in press (18 pages, 17 figures
High risk clinical characteristics for subarachnoid haemorrhage in patients with acute headache: prospective cohort study
Objective To identify high risk clinical characteristics for subarachnoid haemorrhage in neurologically intact patients with headache
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