8,265 research outputs found
Two \u3ci\u3eEntomophthora\u3c/i\u3e Species Associated with Disease Epizootics of the Alfalfa Weevil, \u3ci\u3eHypera Postica\u3c/i\u3e (Coleoptera: Curculionidae), in Ontario
Recent studies have shown that disease epizootics in Ontario populations of the alfalfa weevil, Hypera postica (Gyllenhal), are caused by a complex of two fungi
SDSSJ14584479+3720215: A Benchmark JHK Blazar Light Curve from the 2MASS Calibration Scans
Active galactic nuclei (AGNs) are well-known to exhibit flux variability
across a wide range of wavelength regimes, but the precise origin of the
variability at different wavelengths remains unclear. To investigate the
relatively unexplored near-IR variability of the most luminous AGNs, we conduct
a search for variability using well sampled JHKs-band light curves from the
2MASS survey calibration fields. Our sample includes 27 known quasars with an
average of 924 epochs of observation over three years, as well as one
spectroscopically confirmed blazar (SDSSJ14584479+3720215) with 1972 epochs of
data. This is the best-sampled NIR photometric blazar light curve to date, and
it exhibits correlated, stochastic variability that we characterize with
continuous auto-regressive moving average (CARMA) models. None of the other 26
known quasars had detectable variability in the 2MASS bands above the
photometric uncertainty. A blind search of the 2MASS calibration field light
curves for AGN candidates based on fitting CARMA(1,0) models (damped-random
walk) uncovered only 7 candidates. All 7 were young stellar objects within the
{\rho} Ophiuchus star forming region, five with previous X-ray detections. A
significant {\gamma}-ray detection (5{\sigma}) for the known blazar using 4.5
years of Fermi photon data is also found. We suggest that strong NIR
variability of blazars, such as seen for SDSSJ14584479+3720215, can be used as
an efficient method of identifying previously-unidentified {\gamma}-ray
blazars, with low contamination from other AGN.Comment: 6 pages, 3 figures, ApJ Accepte
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Quantifying the value of ecosystem services: a case study of honeybee pollination in the UK
There is concern that insect pollinators, such as honey bees, are currently declining in abundance, and are under serious threat from environmental changes such as habitat loss and climate change; the use of pesticides in intensive agriculture, and emerging diseases. This paper aims to evaluate how much public support there would be in preventing further decline to maintain the current number of bee colonies in the UK. The contingent valuation method (CVM) was used to obtain the willingness to pay (WTP) for a theoretical pollinator protection policy. Respondents were asked whether they would be WTP to support such a policy and how much would they pay? Results show that the mean WTP to support the bee protection policy was £1.37/week/household. Based on there being 24.9 million households in the UK, this is equivalent to £1.77 billion per year. This total value can show the importance of maintaining the overall pollination service to policy makers. We compare this total with estimates obtained using a simple market valuation of pollination for the UK
Colon capsule endoscopy : an innovative method for detecting colorectal pathology during the Covid-19 pandemic?
Colorectal Disease © 2020 The Association of Coloproctology of Great Britain and Ireland.Peer reviewedPostprin
Runaway Coalescence at the Onset of Common Envelope Episodes
Luminous red nova transients, presumably from stellar coalescence, exhibit
long-term precursor emission over hundreds of binary orbits, leading to
impulsive outbursts with durations similar to a single orbital period. In an
effort to understand these signatures, we present and analyze a hydrodynamic
model of unstable mass transfer from a giant-star donor onto a more compact
accretor in a binary system. Our simulation begins with mass transfer at the
Roche limit separation and traces a phase of runaway decay leading up to the
plunge of the accretor within the envelope of the donor. We characterize the
fluxes of mass and angular momentum through the system and show that the
orbital evolution can be reconstructed from measurements of these quantities.
The morphology of outflow from the binary changes significantly as the binary
orbit tightens. At wide separations, a thin stream of relatively high-entropy
gas trails from the outer Lagrange points. As the orbit tightens, the orbital
motion desynchronizes from the donor's rotation, and low-entropy ejecta trace a
broad fan of largely ballistic trajectories. An order-of-magnitude increase in
mass ejection rate accompanies the plunge of the accretor with the envelope of
the donor. We argue that this transition marks the precursor-to-outburst
transition observed in stellar coalescence transients.Comment: Revised following peer-review. ApJ accepted. Animated version of
Figure 5 will be available via the Journal's online publicatio
Bound Outflows, Unbound Ejecta, and the Shaping of Bipolar Remnants during Stellar Coalescence
Recent observations have revealed that the remnants of stellar-coalescence
transients are bipolar. This raises the questions of how these bipolar
morphologies arise and what they teach us about the mechanisms of mass ejection
during stellar mergers and common-envelope phases. In this paper, we analyze
hydrodynamic simulations of the lead-in to binary coalescence, a phase of
unstable Roche lobe overflow that takes the binary from the Roche limit
separation to the engulfment of the more compact accretor within the envelope
of the extended donor. As mass transfer runs away at increasing rates, gas
trails away from the binary. Contrary to previous expectations, early mass loss
from the system remains bound to the binary and forms a circumbinary torus.
Later ejecta, generated as the accretor grazes the surface of the donor, have
very different morphologies and are unbound. These two components of mass loss
from the binary interact as later, higher-velocity ejecta collide with the
circumbinary torus formed by earlier mass loss. Unbound ejecta are redirected
toward the poles, and escaping material creates a bipolar outflow. Our findings
show that the transition from bound to unbound ejecta from coalescing binaries
can explain the bipolar nature of their remnants, with implications for our
understanding of the origin of bipolar remnants of stellar-coalescence
transients and, perhaps, some preplanetary nebulae.Comment: ApJ accepte
Awareness of lifestyle and colorectal cancer risk:findings from the BeWEL study
It is estimated that 47% of colorectal cancers (CRC) could be prevented by appropriate lifestyles. This study aimed to identify awareness of the causes of CRC in patients who had been diagnosed with a colorectal adenoma through the Scottish Bowel Screening Programme and subsequently enrolled in an intervention trial (using diet and physical activity education and behavioural change techniques) (BeWEL). At baseline and 12-month follow-up, participants answered an open-ended question on factors influencing CRC development. Of the 329 participants at baseline, 40 (12%) reported that they did not know any risk factors and 36 (11%) failed to identify specific factors related to diet and activity. From a potential knowledge score of 1 to 6, the mean score was 1.5 (SD 1.1, range 0 to 5) with no difference between intervention and control groups. At follow-up, the intervention group had a significantly greater knowledge score and better weight loss, diet, and physical activity measures than the control group. Awareness of relevant lifestyle factors for CRC remains low in people at increased risk of the disease. Opportunities within routine NHS screening to aid the capability (including knowledge of risk factors) of individuals to make behavioural changes to reduce CRC risk deserve exploration.Additional co-author: The BeWEL team. The BeWEL Team consists of Shaun Treweek, Fergus Daly, Jill Belch, Jackie Rodger, Alison Kirk, Anne Ludbrook, Petra Rauchhaus, Patricia Norwood, Joyce Thompson, and Jane Wardle
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