2,491 research outputs found
The Palaeo-ecology and Biostratigraphy of the foraminifera from the Oxfordian of north Dorset
The Oxfordian rocks of north Dorset are poorly exposed at outcrop. A drilling operation was
devised and implemented and the complete sequence of strata from the Weymouth Member
of the Oxford Clay Formation through to the Ringstead Waxy Clay Formation was
penetrated. Three boreholes were drilled; the Hallett's Farm Borehole, covering the strata
from the stratigraphically youngest Ringstead Waxy Clay Formation down to the
Cucklington Oolite; the Bowden Farm Borehole, continuing the sequence from the
Cucklington Oolite into the lower part of the Hazelbury Bryan Formation and the Hartmoor
Hill Borehole which continues downward into the Oxford Clay Formation. A continuous
succession of the Corallian rocks from north Dorset was obtained. The fresh borehole
material was examined for microfossils, with further samples coming from the BGS East
Stour Borehole. A diverse assemblage was extracted. The foraminiferal assemblage was
examined and includes representatives of 26 families, comprising 26 genera and 148 species.
All species were identified and the taxonomy of each studied and described or confirmed.
The assemblage is more diverse than previously recorded Corallian assemblages, partly due
to the freshness of the borehole material which is not affected by the weathering processes
present at surface outcrops.
The regional lithostratigraphy defined by the British Geological Survey (Bristow et al,
1995) is confirmed and lithological boundaries not visible at outcrop are described.
The distribution and abundance patterns of foraminiferal taxa are analysed and various
statistical indices are compared for each borehole. Multivariate methods are employed and in
particular non-metric Multidimensional Scaling is used in an attempt to divide the samples
into groups which are palaeo-environmentally significant. The authenticity of this method is
checked against a Hierarchical Agglomerative Clustering technique. The sample groups are
used to define biofacies, fifteen of which are recognised within the studied interval.
The correlation of the four boreholes is achieved using lithological techniques, ammonite
zonation, foraminiferal biohorizons and the biofacies defined by multivariate analysis. A total
of 21 biohorizons are identified with certain horizons coinciding with lithological boundaries
and previously defined unconformities recognised within the Oxfordian of Dorset.
The long ranging nature of the majority of Upper Jurassic foraminifera precludes the
definition of a rigorous biostratigraphic zonation. The important biostratigraphic species for
the Upper Jurassic are recorded however, and a tentative zonation, based on the concept of
interval zones (Salvador, 1995) is proposed. Eleven zones are recognised.British Geological Survey, Exete
Optimal Survey Strategies and Predicted Planet Yields for the Korean Microlensing Telescope Network
The Korean Microlensing Telescope Network (KMTNet) will consist of three 1.6m
telescopes each with a 4 deg^{2} field of view (FoV) and will be dedicated to
monitoring the Galactic Bulge to detect exoplanets via gravitational
microlensing. KMTNet's combination of aperture size, FoV, cadence, and
longitudinal coverage will provide a unique opportunity to probe exoplanet
demographics in an unbiased way. Here we present simulations that optimize the
observing strategy for, and predict the planetary yields of, KMTNet. We find
preferences for four target fields located in the central Bulge and an exposure
time of t_{exp} = 120s, leading to the detection of ~2,200 microlensing events
per year. We estimate the planet detection rates for planets with mass and
separation across the ranges 0.1 <= M_{p}/M_{Earth} <= 1000 and 0.4 <= a/AU <=
16, respectively. Normalizing these rates to the cool-planet mass function of
Cassan (2012), we predict KMTNet will be approximately uniformly sensitive to
planets with mass 5 <= M_{p}/M_{Earth} <= 1000 and will detect ~20 planets per
year per dex in mass across that range. For lower-mass planets with mass 0.1 <=
M_{p}/M_{Earth} < 5, we predict KMTNet will detect ~10 planets per year. We
also compute the yields KMTNet will obtain for free-floating planets (FFPs) and
predict KMTNet will detect ~1 Earth-mass FFP per year, assuming an underlying
population of one such planet per star in the Galaxy. Lastly, we investigate
the dependence of these detection rates on the number of observatories, the
photometric precision limit, and optimistic assumptions regarding seeing,
throughput, and flux measurement uncertainties.Comment: 29 pages, 31 figures, submitted to ApJ. For a brief video explaining
the key results of this paper, please visit:
https://www.youtube.com/watch?v=e5rWVjiO26
BLOOD FLOW RESTRICTION DOES NOT AFFECT ACUTE MEASURES OF POWER AND FATIGUE DURING MAXIMAL CYCLING AMONG WOMEN
While it is known that blood flow restriction (BFR) can positively affect training and rehabilitation progression timelines, the physiological basis of this intervention is not fully understood. The purpose of this study was to determine the short-term impact of BFR upon power and fatigue performance measures during maximal cycling. In this study, maximal cycling was assessed using the Wingate Anaerobic Test (WAnT). Using a counterbalanced design, fourteen female participants completed standardized BFR and non-BFR protocols while completing the WAnT. No statistically-significant differences (p †0.05) were found between conditions for measures of peak power (PP), low power (LP) or fatigue index (FI). These findings suggest that BFR had no statistically-significant acute effect on these performance measures commonly assessed during the WAnT
THE EFFECTS OF BLOOD FLOW RESTRICTION ON MEASURES OF GROSS MOTOR COORDINATION DURING THE WINGATE ANAEROBIC TEST
To date little research has addressed the impact of blood flow restriction (BFR) training upon gross motor coordination measures (GMCM) during a wide variety of maximal activities. The purpose of this study was to assess the effects of BFR on GMCM exhibited during maximal cycling. The performance of 14 females between the ages of eighteen and thirty-five were analyzed during the Wingate Anaerobic Test (WAnT). The participants completed the test under two conditions, using BFR and without. Results showed statistically significant differences (p †0.05) between conditions for dependent variables assessed throughout this common 30 second test of maximal cycling. These findings suggest that BFR negatively influenced GMCM exhibited during the WAnT
Planet Sensitivity from Combined Ground- and Space-based Microlensing Observations
To move one step forward toward a Galactic distribution of planets, we
present the first planet sensitivity analysis for microlensing events with
simultaneous observations from space and the ground. We present this analysis
for two such events, OGLE-2014-BLG-0939 and OGLE-2014-BLG-0124, which both show
substantial planet sensitivity even though neither of them reached high
magnification. This suggests that an ensemble of low to moderate magnification
events can also yield significant planet sensitivity and therefore probability
to detect planets. The implications of our results to the ongoing and future
space-based microlensing experiments to measure the Galactic distribution of
planets are discussed.Comment: 10 pages, 5 figures, 1 table; ApJ in pres
Effect of Gene Therapy on Visual Function in Leber's Congenital Amaurosis
Early-onset, severe retinal dystrophy caused by mutations in the gene encoding retinal pigment epitheliumâspecific 65-kD protein (RPE65) is associated with poor vision at birth and complete loss of vision in early adulthood. We administered to three young adult patients subretinal injections of recombinant adeno-associated virus vector 2/2 expressing RPE65 complementary DNA (cDNA) under the control of a human RPE65 promoter. There were no serious adverse events. There was no clinically significant change in visual acuity or in peripheral visual fields on Goldmann perimetry in any of the three patients. We detected no change in retinal responses on electroretinography. One patient had significant improvement in visual function on microperimetry and on dark-adapted perimetry. This patient also showed improvement in a subjective test of visual mobility. These findings provide support for further clinical studies of this experimental approach in other patients with mutant RPE65. (ClinicalTrials.gov number, NCT00643747.)Supported by grants from the U.K. Department of Health, the
British Retinitis Pigmentosa Society, and the Special Trustees of
Moorfields Eye Hospital, and by the Sir Jules Thorn Charitable
Trust, the Wellcome Trust, the European Union (EVI-Genoret
and Clinigene programs), the Medical Research Council, Foundation
Fighting Blindness, Fight for Sight, the Ulverscroft Foundation,
Fighting Blindness (Ireland), Moorfields Eye Hospital,
and Institute of Ophthalmology Biomedical Research Centre for
Ophthalmology, University College London
OGLE-2018-BLG-0022: First Prediction of an Astrometric Microlensing Signal from a Photometric Microlensing Event
In this work, we present the analysis of the binary microlensing event
OGLE-2018-BLG-0022 that is detected toward the Galactic bulge field. The dense
and continuous coverage with the high-quality photometry data from ground-based
observations combined with the space-based {\it Spitzer} observations of this
long time-scale event enables us to uniquely determine the masses and of the individual lens components.
Because the lens-source relative parallax and the vector lens-source relative
proper motion are unambiguously determined, we can likewise unambiguously
predict the astrometric offset between the light centroid of the magnified
images (as observed by the {\it Gaia} satellite) and the true position of the
source. This prediction can be tested when the individual-epoch {\it Gaia}
astrometric measurements are released.Comment: 10 pages, 10 figures, 4 table
Parallax of OGLE-2018-BLG-0596: A Low-mass-ratio Planet around an M-dwarf
We report the discovery of a microlensing planet
OGLE-2018-BLG-0596Lb, with preferred planet-host mass ratio . The planetary signal, which is characterized by a short "bump" on the rising side of the lensing light curve, was densely
covered by ground-based surveys. We find that the signal can be explained by a
bright source that fully envelops the planetary caustic, i.e., a "Hollywood"
geometry. Combined with the source proper motion measured from , the
satellite parallax measurement makes it possible to precisely
constrain the lens physical parameters. The preferred solution, in which the
planet perturbs the minor image due to lensing by the host, yields a
Uranus-mass planet with a mass of orbiting
a mid M-dwarf with a mass of . There is also
a second possible solution that is substantially disfavored but cannot be ruled
out, for which the planet perturbs the major image. The latter solution yields
and . By
combining the microlensing and data together with a Galactic model, we
find in either case that the lens lies on the near side of the Galactic bulge
at a distance . Future adaptive optics
observations may decisively resolve the major image/minor image degeneracy.Comment: 34 pages, 8 figures, Submitted to AAS journa
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