803 research outputs found
On peer reviewing: how to nourish an authorâs mind and win a JLDHE editorâs heart
No embargo required.Editors and publishers of scholarly journals rarely agree on what makes for a good publication; they do, however, agree on the need for a robust peer review process as a crucial means to judge the merits of potential publications. While fraught with issues and inefficiencies, a critical and supportive peer review is not only what editors rely on when assessing scholarship presented for publication but also what authors hope for in order to improve their work. Understanding how peer review may best serve all parties involved: authors, editors, and reviewers, is thus at the heart of this article. The analysis offered here is based on a session the Journal for Learning Development in Higher Education editors gave at the 2020 LD@3 seminar series, entitled âThe Art of Reviewingâ. It explores the different aspects of the peer review process while formulating recommendations regarding best practices and outlining JLDHE initiatives for supporting reviewersâ vital work.</jats:p
Easily retrievable objects among the NEO population
Asteroids and comets are of strategic importance for science in an effort to understand the formation, evolution and composition of the Solar System. Near-Earth Objects (NEOs) are of particular interest because of their accessibility from Earth, but also because of their speculated wealth of material resources. The exploitation of these resources has long been discussed as a means to lower the cost of future space endeavours. In this paper, we consider the currently known NEO population and define a family of so-called Easily Retrievable Objects (EROs), objects that can be transported from accessible heliocentric orbits into the Earthâs neighbourhood at affordable costs. The asteroid retrieval transfers are sought from the continuum of low energy transfers enabled by the dynamics of invariant manifolds; specifically, the retrieval transfers target planar, vertical Lyapunov and halo orbit families associated with the collinear equilibrium points of the Sun-Earth Circular Restricted Three Body problem. The judicious use of these dynamical features provides the best opportunity to find extremely low energy Earth transfers for asteroid material. A catalogue of asteroid retrieval candidates is then presented. Despite the highly incomplete census of very small asteroids, the ERO catalogue can already be populated with 12 different objects retrievable with less than 500 m/s of Îv. Moreover, the approach proposed represents a robust search and ranking methodology for future retrieval candidates that can be automatically applied to the growing survey of NEOs
Photometry of cometary nuclei: Rotation rates, colours and a comparison with Kuiper Belt Objects
We present time-series data on Jupiter Family Comets (JFCs) 17P/Holmes,
47P/Ashbrook-Jackson and 137P/Shoemaker-Levy 2. In addition we also present
results from `snap-shot' observations of comets 43P/Wolf-Harrington,
44P/Reinmuth 2, 103P/Hartley 2 and 104P/Kowal 2 taken during the same run. The
comets were at heliocentric distances of between 3 and 7 AU at this time. We
present measurements of size and activity levels for the snap-shot targets. The
time-series data allow us to constrain rotation periods and shapes, and thus
bulk densities. We also measure colour indices (V-R) and (R-I) and reliable
radii for these comets. We compare all of our findings to date with similar
results for other comets and Kuiper Belt Objects (KBOs). We find that the
rotational properties of nuclei and KBOs are very similar, that there is
evidence for a cut-off in bulk densities at ~ 0.6 g cm^{-3} in both
populations, and the colours of the two populations show similar correlations.
For JFCs there is no observational evidence for the optical colours being
dependant on either position in the orbit or on orbital parameters.Comment: 15 pages, 19 figures, accepted for publication in MNRA
The Applications of GIS in the Analysis of the Impacts of Human Activities on South Texas Watersheds
With water resource planning assuming greater importance in environmental protection efforts, analyzing the health of agricultural watersheds using Geographic Information Systems (GIS) becomes essential for decision-makers in Southern Texas. Within the area, there exist numerous threats from conflicting land uses. These include the conversion of land formerly designated for agricultural purposes to other uses. Despite current efforts, anthropogenic factors are greatly contributing to the degradation of watersheds. Additionally, the activities of waste water facilities located in some of the counties, rising populations, and other socioeconomic variables are negatively impacting the quality of water in the agricultural watersheds. To map the location of these stressors spatially and the extent of their impacts across time, the paper adopts a mix scale method of temporal spatial analysis consisting of simple descriptive statistics. In terms of objectives, this research provides geo-spatial analysis of the effects of human activities on agricultural watersheds in Southern Texas and the factors fuelling the concerns under the purview of watershed management. The results point to growing ecosystem decline across time and a geographic cluster of counties experiencing environmental stress. Accordingly, the emergence of stressors such as rising population, increased use of fertilizer treatments on farm land, discharges of atmospheric pollutants and the large presence of municipal and industrial waste treatment facilities emitting pathogens and pesticides directly into the agricultural watersheds pose a growing threat to the quality of the watershed ecosystem
Characterization of the near-Earth Asteroid 2002NY40
In August 2002, the near-Earth asteroid 2002 NY40, made its closest approach
to the Earth. This provided an opportunity to study a near-Earth asteroid with
a variety of instruments. Several of the telescopes at the Maui Space
Surveillance System were trained at the asteroid and collected adaptive optics
images, photometry and spectroscopy. Analysis of the imagery reveals the
asteroid is triangular shaped with significant self-shadowing. The photometry
reveals a 20-hour period and the spectroscopy shows that the asteroid is a
Q-type
Spectra of High-Redshift Type Ia Supernovae and a Comparison with their Low-Redshift Counterparts
We present spectra for 14 high-redshift (0.17 < z < 0.83) supernovae, which
were discovered by the Supernova Cosmology Project as part of a campaign to
measure cosmological parameters. The spectra are used to determine the redshift
and classify the supernova type, essential information if the supernovae are to
be used for cosmological studies. Redshifts were derived either from the
spectrum of the host galaxy or from the spectrum of the supernova itself. We
present evidence that these supernovae are of Type Ia by matching to spectra of
nearby supernovae. We find that the dates of the spectra relative to maximum
light determined from this fitting process are consistent with the dates
determined from the photometric light curves, and moreover the spectral
time-sequence for SNe Type Ia at low and high redshift is indistinguishable. We
also show that the expansion velocities measured from blueshifted CaHK are
consistent with those measured for low-redshift Type Ia supernovae. From these
first-level quantitative comparisons we find no evidence for evolution in SNIa
properties between these low- and high-redshift samples. Thus even though our
samples may not be complete, we conclude that there is a population of SNe Ia
at high redshift whose spectral properties match those at low redshift.Comment: Accepted for publication in AJ. Also available at
http://supernova.lbl.gov
Near-IR search for lensed supernovae behind galaxy clusters: I. Observations and transient detection efficiency
Massive galaxy clusters at intermediate redshift can magnify the flux of
distant background sources by several magnitudes and we exploit this effect to
search for lensed distant supernovae that may otherwise be too faint to be
detected. A supernova search was conducted at near infrared wavelengths using
the ISAAC instrument at the VLT. The galaxy clusters Abell 1689, Abell 1835 and
AC114 were observed at multiple epochs of 2 hours of exposure time, separated
by a month. Image-subtraction techniques were used to search for transient
objects with light curve properties consistent with supernovae, both in our new
and archival ISAAC/VLT data. The limiting magnitude of the individual epochs
was estimated by adding artificial stars to the subtracted images. Most of the
epochs reach 90% detection efficiency at SZ(J) ~= 23.8-24.0 mag (Vega). Two
transient objects, both in archival images of Abell 1689 and AC114, were
detected. The transient in AC114 coincides - within the position uncertainty -
with an X-ray source and is likely to be a variable AGN at the cluster
redshift. The transient in Abell 1689 was found at SZ=23.24 mag, ~0.5 arcsec
away from a galaxy with photometric redshift z=0.6 +/-0.15. The light curves
and the colors of the transient are consistent with a reddened Type IIP
supernova at redshift z=0.59 +/- 0.05. The lensing model of Abell 1689 predicts
~1.4 mag of magnification at the position of the transient, making it the most
magnified supernova ever found and only the second supernova found behind a
galaxy cluster. Our pilot survey has demonstrated the feasibility to find
distant gravitationally magnified supernovae behind massive galaxy clusters.
One likely supernova was found behind Abell 1689, in accordance with the
expectations for this survey, as shown in an accompanying analysis paper.Comment: Language-edited version, 9 pages, 6 figures, accepted by A&
The molecular landscape and associated clinical experience in infant medulloblastoma: prognostic significance of second-generation subtypes
Aims:
Biomarkerâdriven therapies have not been developed for infant medulloblastoma (iMB). We sought to robustly subâclassify iMB, and proffer strategies for personalized, riskâadapted therapies.
Methods:
We characterized the iMB molecular landscape, including secondâgeneration subtyping, and the associated retrospective clinical experience, using large independent discovery/validation cohorts (n = 387).
Results:
iMBGrp3 (42%) and iMBSHH (40%) subgroups predominated. iMBGrp3 harboured secondâgeneration subtypes II/III/IV. Subtype II strongly associated with largeâcell/anaplastic pathology (LCA; 23%) and MYC amplification (19%), defining a veryâhighârisk group (0% 10yr overall survival (OS)), which progressed rapidly on all therapies; novel approaches are urgently required. Subtype VII (predominant within iMBGrp4) and subtype IV tumours were standard risk (80% OS) using upfront CSIâbased therapies; randomizedâcontrolled trials of upfront radiationâsparing and/or secondâline radiotherapy should be considered. Seventyâfive per cent of iMBSHH showed DN/MBEN histopathology in discovery and validation cohorts (P < 0.0001); central pathology review determined diagnosis of histological variants to WHO standards. In multivariable models, nonâDN/MBEN pathology was associated significantly with worse outcomes within iMBSHH. iMBSHH harboured two distinct subtypes (iMBSHHâI/II). Within the discriminated favourableârisk iMBSHH DN/MBEN patient group, iMBSHHâII had significantly better progressionâfree survival than iMBSHHâI, offering opportunities for riskâadapted stratification of upfront therapies. Both iMBSHHâI and iMBSHHâII showed notable rescue rates (56% combined postârelapse survival), further supporting delay of irradiation. Survival models and risk factors described were reproducible in independent cohorts, strongly supporting their further investigation and development.
Conclusions:
Investigations of large, retrospective cohorts have enabled the comprehensive and robust characterization of molecular heterogeneity within iMB. Novel subtypes are clinically significant and subgroupâdependent survival models highlight opportunities for biomarkerâdirected therapies
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