Measurement of the Nodal Precession of WASP-33 b via Doppler Tomography

We have analyzed new and archival time series spectra taken six years apart during transits of the hot Jupiter WASP-33 b, and spectroscopically resolved the line profile perturbation caused by the Rossiter-McLaughlin effect. The motion of this line profile perturbation is determined by the path of the planet across the stellar disk, which we show to have changed between the two epochs due to nodal precession of the planetary orbit. We measured rates of change of the impact parameter and the sky-projected spin-orbit misalignment of $db/dt=-0.0228_{-0.0018}^{+0.0050}$ yr$^{-1}$ and $d\lambda/dt=-0.487_{-0.076}^{+0.089}$~$^{\circ}$ yr$^{-1}$, respectively, corresponding to a rate of nodal precession of $d\Omega/dt=0.373_{-0.083}^{+0.031}$~$^{\circ}$ yr$^{-1}$. This is only the second measurement of nodal precession for a confirmed exoplanet transiting a single star. Finally, we used the rate of precession to set limits on the stellar gravitational quadrupole moment of $9.4\times10^{-5}<J_2<6.1\times10^{-4}$.Comment: Published in ApJL. 5 pages, 3 figures. Corrected error in the calculation of J_

The evolution of mechanisms underlying behaviour

This is the final version of the article. It first appeared from Oxford University press via http://www.scopus.com/record/display.uri?eid=2-s2.0-84925394342&origin=inward&txGid=0-This work was funded by the European Research Council (Advanced Grant 250209 to Alasdair Houston)

Nautilus pompilius Life History and Demographics at the Osprey Reef Seamount, Coral Sea, Australia

Nautiloids are the subject of speculation as to their threatened status arising from the impacts of targeted fishing for the ornamental shell market. Life history knowledge is essential to understand the susceptibility of this group to overfishing and to the instigation of management frameworks. This study provides a comprehensive insight into the life of Nautilus in the wild. At Osprey Reef from 1998–2008, trapping for Nautilus was conducted on 354 occasions, with 2460 individuals of one species, Nautilus pompilius, captured and 247 individuals recaptured. Baited remote underwater video systems (BRUVS) were deployed on 15 occasions and six remotely operated vehicle (ROV) dives from 100–800 m were conducted to record Nautilus presence and behavior. Maturity, sex and size data were recorded, while measurements of recaptured individuals allowed estimation of growth rates to maturity, and longevity beyond maturity. We found sexual dimorphism in size at maturity (males: 131.9±SD = 2.6 mm; females: 118.9±7.5 mm shell diameter) in a population dominated by mature individuals (58%). Mean growth rates of 15 immature recaptured animals were 0.061±0.023 mm day−1 resulting in an estimate of around 15.5 years to maturation. Recaptures of mature animals after five years provide evidence of a lifespan exceeding 20 years. Juvenile Nautilus pompilius feeding behavior was recorded for the first time within the same depth range (200–610 m) as adults. Our results provide strong evidence of a K-selected life history for Nautilus from a detailed study of a ‘closed’ wild population. In conjunction with population size and density estimates established for the Osprey Reef Nautilus, this work allows calculations for sustainable catch and provides mechanisms to extrapolate these findings to other extant nautiloid populations (Nautilus and Allonautilus spp.) throughout the Indo-Pacific

Cell exclusion in couette flow:evaluation through flow visualisation and mechanical forces

Cell exclusion is the phenomenon whereby the hematocrit and viscosity of blood decrease in areas of high stress. While this is well known in naturally occurring Poiseuille flow in the human body, it has never previously been shown in Couette flow, which occurs in implantable devices including blood pumps. The high-shear stresses that occur in the gap between the boundaries in Couette flow are known to cause hemolysis in erythrocytes. We propose to mitigate this damage by initiating cell exclusion through the use of a spiral-groove bearing (SGB) that will provide escape routes by which the cells may separate themselves from the plasma and the high stresses in the gap. The force between two bearings (one being the SGB) in Couette flow was measured. Stained erythrocytes, along with silver spheres of similar diameter to erythrocytes, were visualized across a transparent SGB at various gap heights. A reduction in the force across the bearing for human blood, compared with fluids of comparable viscosity, was found. This indicates a reduction in the viscosity of the fluid across the bearing due to a lowered hematocrit because of cell exclusion. The corresponding images clearly show both cells and spheres being excluded from the gap by entering the grooves. This is the first time the phenomenon of cell exclusion has been shown in Couette flow. It not only furthers our understanding of how blood responds to different flows but could also lead to improvements in the future design of medical devices

Violent behaviour detection using local trajectory response

Surveillance systems in the United Kingdom are prominent, and the number of installed cameras is estimated to be around 1.8 million. It is common for a single person to watch multiple live video feeds when conducting active surveillance, and past research has shown that a person’s effectiveness at successfully identifying an event of interest diminishes the more monitors they must observe. We propose using computer vision techniques to produce a system that can accurately identify scenes of violent behaviour. In this paper we outline three measures of motion trajectory that when combined produce a response map that highlights regions within frames that contain behaviour typical of violence based on local information. Our proposed method demonstrates state-of-the-art classification ability when given the task of distinguishing between violent and non-violent behaviour across a wide variety of violent data, including real-world surveillance footage obtained from local police organisations

The secret world of shrimps: polarisation vision at its best

Animal vision spans a great range of complexity, with systems evolving to detect variations in optical intensity, distribution, colour, and polarisation. Polarisation vision systems studied to date detect one to four channels of linear polarisation, combining them in opponent pairs to provide intensity-independent operation. Circular polarisation vision has never been seen, and is widely believed to play no part in animal vision. Polarisation is fully measured via Stokes' parameters--obtained by combined linear and circular polarisation measurements. Optimal polarisation vision is the ability to see Stokes' parameters: here we show that the crustacean \emph{Gonodactylus smithii} measures the exact components required. This vision provides optimal contrast-enhancement, and precise determination of polarisation with no confusion-states or neutral-points--significant advantages. We emphasise that linear and circular polarisation vision are not different modalities--both are necessary for optimal polarisation vision, regardless of the presence of strongly linear or circularly polarised features in the animal's environment.Comment: 10 pages, 6 figures, 2 table

Dietary patterns associated with dental caries in adults in the United States

ObjectivesDental caries experience, which affects 91% of US adults, is a consequence of a carious process influenced by diet. Although individual foods have been implicated, we hypothesized that dietary patterns might be important predictors of caries presence.MethodsWe analysed data from 4467 people ≥18 years old participating in the 2013‐2014 National Health and Nutrition Examination Survey, a nationally representative sample of the US population. Data from 24‐hour dietary recalls were classified into standard food categories and reduced to three dietary patterns using principal components (PCs) analysis. We used regression to model the log‐transformed decayed, missing and filled teeth (DMFT) score and the prevalence of any caries experience by quartiles of PC scores, controlling for potential confounders. Dietary patterns differed by age with respect to dental caries so 18‐30‐year‐olds (n = 1074) and >30‐year‐olds (n = 3393) were analysed separately.ResultsSimilar dietary patterns existed among individuals aged 18‐30 and >30 years, but the prevalence of DMFT score >0 and the median of DMFT was greater in those >30:78.7% (95% CI: 76.1, 81.3) vs 92.6% (95% CI: 91.4, 93.7) and 4 (95% CI: 4, 5) vs 12 DMFT (95% CI: 11, 13), respectively. In those 18‐30, no dietary pattern was associated with greater prevalence or severity of dental caries experience. Among those >30, the prevalence of DMFT>0 was higher by 2% for those in each subsequent quartile of a diet high in sugar‐sweetened beverages and sandwiches (adjusted PR: 1.02, 95% CI: 1.001, 1.03)—thus, the prevalence of dental caries experience was 6% higher among those in the uppermost quartile than in the lowest quartile. For every subsequent quartile in the same pattern, there was a 1.98% higher (95% CI: 0.15, 3.85) DMFT score. However, analysis using the two strongest loading food groups from any of the PCs did not identify any predictors of caries experience.ConclusionsDietary patterns were associated with the prevalence of dental caries experience, with differing findings by age. Although effect sizes were small, the population impact may be substantial. While food groups high in sugar were associated with caries prevalence and severity, associations were more apparent in the context of overall diet. Prospective studies are needed to confirm whether particular dietary patterns are causally related to the development of dental caries.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154279/1/cdoe12509_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154279/2/cdoe12509.pd

A Review of NASA's Radiation-Hardened Electronics for Space Environments Project

NASA's Radiation Hardened Electronics for Space Exploration (RHESE) project develops the advanced technologies required to produce radiation hardened electronics, processors, and devices in support of the requirements of NASA's Constellation program. Over the past year, multiple advancements have been made within each of the RHESE technology development tasks that will facilitate the success of the Constellation program elements. This paper provides a brief review of these advancements, discusses their application to Constellation projects, and addresses the plans for the coming year

An examination of the precipitation delivery mechanisms for Dolleman Island, eastern Antarctic Peninsula

Copyright @ 2004 Wiley-BlackwellThe variability of size and source of significant precipitation events were studied at an Antarctic ice core drilling site: Dolleman Island (DI), located on the eastern coast of the Antarctic Peninsula. Significant precipitation events that occur at DI were temporally located in the European Centre for Medium-Range Weather Forecasting (ECMWF) reanalysis data set, ERA-40. The annual and summer precipitation totals from ERA-40 at DI both show significant increases over the reanalysis period. Three-dimensional backwards air parcel trajectories were then run for 5 d using the ECMWF ERA-15 wind fields. Cluster analyses were performed on two sets of these backwards trajectories: all days in the range 1979–1992 (the climatological time-scale) and a subset of days when a significant precipitation event occurred. The principal air mass sources and delivery mechanisms were found to be the Weddell Sea via lee cyclogenesis, the South Atlantic when there was a weak circumpolar trough (CPT) and the South Pacific when the CPT was deep. The occurrence of precipitation bearing air masses arriving via a strong CPT was found to have a significant correlation with the southern annular mode (SAM); however, the arrival of air masses from the same region over the climatological time-scale showed no such correlation. Despite the dominance in both groups of back trajectories of the westerly circulation around Antarctica, some other key patterns were identified. Most notably there was a higher frequency of lee cyclogenesis events in the significant precipitation trajectories compared to the climatological time-scale. There was also a tendency for precipitation trajectories to come from more northerly latitudes, mostly from 50–70°S. The El Niño Southern Oscillation (ENSO) was found to have a strong influence on the mechanism by which the precipitation was delivered; the frequency of occurrence of precipitation from the east (west) of DI increased during El Niño (La Niña) events