7,282 research outputs found
Impact of Pesticide Residue Concerns on Fresh Produce Consumption in the UK
Pesticide, AIDS, two-stage demand system, Food Consumption/Nutrition/Food Safety, Q11,
On the spectroastrometric separation of binary point-source fluxes
Spectroastrometry is a technique which has the potential to resolve flux
distributions on scales of milliarcseconds. In this study, we examine the
application of spectroastrometry to binary point sources which are spatially
unresolved due to the observational point spread function convolution. The
technique uses measurements with sub-pixel accuracy of the position centroid of
high signal-to-noise long-slit spectrum observations. With the objects in the
binary contributing fractionally more or less at different wavelengths
(particularly across spectral lines), the variation of the position centroid
with wavelength provides some information on the spatial distribution of the
flux. We examine the width of the flux distribution in the spatial direction,
and present its relation to the ratio of the fluxes of the two components of
the binary. Measurement of three observables (total flux, position centroid and
flux distribution width) at each wavelength allows a unique separation of the
total flux into its component parts even though the angular separation of the
binary is smaller than the observations' point-spread function. This is because
we have three relevant observables for three unknowns (the two fluxes, and the
angular separation of the binary), which therefore generates a closed problem.
This is a wholly different technique than conventional deconvolution methods,
which produce information on angular sizes of the sampling scale.
Spectroastrometry can produce information on smaller scales than conventional
deconvolution, and is successful in separating fluxes in a binary object with a
separation of less than one pixel. We present an analysis of the errors
involved in making binary object spectroastrometric measurements and the
separation method, and highlight necessary observing methodology.Comment: 11 pages, 8 figures, accepted for publication in Astronomy and
Astrophysic
Investigating Driver Evasive Maneuvers of Takeover Responses in Automated Vehicles
When an automated vehicle (AV) is about to crash, would the speed of the AV (slow vs. fast) affect the steering direction of a human driver who attempts to control the vehicle and avoid the collision? Answering this question provides AV manufacturers insight into how they can produce a safer AV experience for human drivers. Considering that a left turn at a T-intersection allows a greater time budget to make the turn than a right turn which requires sharper steering, we hypothesized that drivers traveling at faster speeds would be more likely to turn left and drivers traveling at moderately slow speeds would turn right to avoid a collision. To test these hypotheses, we conducted a driving simulator experiment where participants monitored the AV’s status throughout the driving. We manipulated the speed of the AV when it crashes at a T-intersection (approximately 7 m/s vs. 11 m/s). Our results indicated that the speed of the vehicle had no impact on the steering direction. Interestingly, however, drivers displayed an overall inclination towards right turns to avoid collision at the T-intersection regardless of speed conditions.
Keywords: automated vehicle (AV), speed, right turn, left turn, T-intersectio
GOLLUM: a next-generation simulation tool for electron, thermal and spin transport
We have developed an efficient simulation tool 'GOLLUM' for the computation
of electrical, spin and thermal transport characteristics of complex
nanostructures. The new multi-scale, multi-terminal tool addresses a number of
new challenges and functionalities that have emerged in nanoscale-scale
transport over the past few years. To illustrate the flexibility and
functionality of GOLLUM, we present a range of demonstrator calculations
encompassing charge, spin and thermal transport, corrections to density
functional theory such as LDA+U and spectral adjustments, transport in the
presence of non-collinear magnetism, the quantum-Hall effect, Kondo and Coulomb
blockade effects, finite-voltage transport, multi-terminal transport, quantum
pumps, superconducting nanostructures, environmental effects and pulling curves
and conductance histograms for mechanically-controlled-break-junction
experiments.Comment: 66 journal pages, 57 figure
Methamphetamine abstinence induces changes in μ-opioid receptor, oxytocin and CRF systems: Association with an anxiogenic phenotype
The major challenge in treating methamphetamine addicts is the maintenance of a drug free-state since they experience negative emotional symptoms during abstinence, which may trigger relapse. The neuronal mechanisms underlying long-term withdrawal and relapse are currently not well-understood. There is evidence suggesting a role of the oxytocin (OTR), μ-opioid receptor (MOPr), dopamine D2 receptor (D2R), corticotropin-releasing factor (CRF) systems and the hypothalamic-pituitary-adrenal (HPA)-axis in the different stages of methamphetamine addiction. In this study, we aimed to characterize the behavioral effects of methamphetamine withdrawal in mice and to assess the modulation of the OTR, MOPr, D2R, CRF and HPA-axis following chronic methamphetamine administration and withdrawal. Ten-day methamphetamine administration (2 mg/kg) increased OTR binding in the amygdala, whilst 7 days of withdrawal induced an upregulation of this receptor in the lateral septum. Chronic methamphetamine treatment increased plasma OT levels that returned to control levels following withdrawal. In addition, methamphetamine administration and withdrawal increased striatal MOPr binding, as well as c-Fos+/CRF+ neuronal expression in the amygdala, whereas an increase in plasma corticosterone levels was observed following METH administration, but not withdrawal. No differences were observed in the D2R binding following METH administration and withdrawal. The alterations in the OTR, MOPr and CRF systems occurred concomitantly with the emergence of anxiety-related symptoms and the development of psychomotor sensitization during withdrawal. Collectively, our findings indicate that chronic methamphetamine use and abstinence can induce brain-region specific neuroadaptations of the OTR, MOPr and CRF systems, which may, at least, partly explain the withdrawal-related anxiogenic effects
Collection and consumption of echinoderms and crustaceans at the Mesolithic shell midden site of El Mazo (northern Iberia) : Opportunistic behaviour or social strategy?
Recent studies in Atlantic Europe on crab remains, goose barnacles and sea urchins have revealed that these species can be of great help in determining patterns of shellfish collection and providing new information on subsistence strategies of hunter-fisher-gatherers. Current excavations at the Mesolithic shell midden site of El Mazo cave (Asturias, northern Iberia) have produced a sizeable amount of crustacean and echinoderm remains from a long stratigraphic sequence that covers an important part of the Mesolithic chronological range, providing the opportunity to investigate long-term exploitation patterns. Results show that echinoderms (sea urchins) and crustaceans (goose barnacles and crabs) were present throughout all of the stratigraphic units (from 8.9 to 7.6 cal kyr), suggesting that they were a persistently exploited food source. However, these resources were not intensively exploited, save perhaps sea urchins at the base of the sequence. From a quantitative perspective, these resources have been traditionally interpreted as minor resources exploited opportunistically to help group survival. However, given the pattern of continuous exploitation exhibited by these resources in northern Iberia and other areas of Atlantic Europe, we suggest that they can be interpreted from a qualitative perspective as stable resources with a significant social valu
Human PrimPol mutation associated with high myopia has a DNA replication defect
PrimPol is a primase-polymerase found in humans, and other eukaryotes, involved in bypassing lesions encountered during DNA replication. PrimPol employs both translesion synthesis and repriming mechanisms to facilitate lesion bypass by the replisome. PrimPol has been reported to be a potential susceptibility gene associated with the development of myopia. Mutation of tyrosine 89 to aspartic acid (PrimPolY89D) has been identified in a number of cases of high myopia, implicating it in the aetiology of this disorder. Here, we examined whether this mutation resulted in any changes in the molecular and cellular activities associated with human PrimPol. We show that PrimPolY89D has a striking decrease in primase and polymerase activities. The hydrophobic ring of tyrosine is important for retaining wild-type extension activity. We also demonstrate that the decreased activity of PrimPolY89D is associated with reduced affinities for DNA and nucleotides, resulting in diminished catalytic efficiency. Although the structure and stability of PrimPolY89D is altered, its fidelity remains unchanged. This mutation also reduces cell viability after DNA damage and significantly slows replication fork rates in vivo. Together, these findings establish that the major DNA replication defect associated with this PrimPol mutant is likely to contribute to the onset of high myopia
Geometry of Paraquaternionic Kahler manifolds with torsion
We study the geometry of PQKT-connections. We find conditions to the
existence of a PQKT-connection and prove that if it exists it is unique. We
show that PQKT geometry persist in a conformal class of metrics.Comment: 22 page
- …