801 research outputs found
Toward integrated conservation of North America's crop wild relatives
North America harbors a rich native flora of crop wild relatives—the progenitors and closely related species of domesticated plants—as well as a range of culturally significant wild utilized plants. Despite their current and potential future value, they are rarely prioritized for conservation efforts; thus many species are threatened in their natural habitats, and most are underrepresented in plant genebanks and botanical gardens. Further coordination of efforts among land management, botanical, and agricultural science organizations will improve conservation and general public awareness with regard to these species. We present examples of productive collaborations focused on wild cranberries (Vaccinium macrocarpon and Vaccinium oxycoccos) and chile peppers (Capsicum annuum var. glabriusculum). We then discuss five shared priorities for further action: (1) understand and document North America's crop wild relatives and wild utilized plants, (2) protect threatened species in their natural habitats, (3) collect and conserve ex situ the diversity of prioritized species, (4) make this diversity accessible and attractive for plant breeding, research, and education, and (5) raise public awareness of their value and the threats to their persistence
Risk factors associated with detailed reproductive phenotypes in dairy and beef cows
peer-reviewedThis article was first published in animal, Volume 8, Issue 05, May 2014, pp 695-703, © The Animal Consortium 2014The objective of this study was to identify detailed fertility traits in dairy and beef cattle from transrectal ultrasonography records
and quantify the associated risk factors. Data were available on 148 947 ultrasound observations of the reproductive tract from
75 949 cows in 843 Irish dairy and beef herds between March 2008 and October 2012. Traits generated included (1) cycling at
time of examination, (2) cystic structures, (3) early ovulation, (4) embryo death and (5) uterine score; the latter was measured on a
scale of 1 (good) to 4 (poor) characterising the tone of the uterine wall and fluid present in the uterus. After editing, 72 773
records from 44 415 dairy and beef cows in 643 herds remained. Factors associated with the logit of the probability of a positive
outcome for each of the binary fertility traits were determined using generalised estimating equations; linear mixed model analysis
was used for the analysis of uterine score. The prevalence of cycling, cystic structures, early ovulation and embryo death was
84.75%, 3.87%, 7.47% and 3.84%, respectively. The occurrence of the uterine heath score of 1, 2, 3 and 4 was 70.63%, 19.75%,
8.36% and 1.26%, respectively. Cows in beef herds had a 0.51 odds (95% CI = 0.41 to 0.63, P<0.001) of cycling at the time of
examination compared with cows in dairy herds; stage of lactation at the time of examination was the same in both herd types.
Furthermore, cows in dairy herds had an inferior uterine score (indicating poorer tone and a greater quantity of uterine fluid
present) compared with cows in beef herds. The likelihood of cycling at the time of examination increased with parity and stage of
lactation, but was reduced in cows that had experienced dystocia in the previous calving. The presence of cystic structures on the
ovaries increased with parity and stage of lactation. The likelihood of embryo/foetal death increased with parity and stage of
lactation. Dystocia was not associated with the presence of cystic structures or embryo death. Uterine score improved with parity
and stage of lactation, while cows that experienced dystocia in the previous calving had an inferior uterine score. Heterosis was
the only factor associated with increased likelihood of early ovulation. The fertility traits identified, and the associated risk factors,
provide useful information on the reproductive status of dairy and beef cows.Funding from the Department of Agriculture, Food and Marine Research Stimulus Fund (RSF 11/S/133) and the OptiMIR project is gratefully acknowledged
The Murchison Widefield Array Transients Survey (MWATS). A search for low frequency variability in a bright Southern hemisphere sample
We report on a search for low-frequency radio variability in 944 bright (>
4Jy at 154 MHz) unresolved, extragalactic radio sources monitored monthly for
several years with the Murchison Widefield Array. In the majority of sources we
find very low levels of variability with typical modulation indices < 5%. We
detect 15 candidate low frequency variables that show significant long term
variability (>2.8 years) with time-averaged modulation indices M = 3.1 - 7.1%.
With 7/15 of these variable sources having peaked spectral energy
distributions, and only 5.7% of the overall sample having peaked spectra, we
find an increase in the prevalence of variability in this spectral class. We
conclude that the variability seen in this survey is most probably a
consequence of refractive interstellar scintillation and that these objects
must have the majority of their flux density contained within angular diameters
less than 50 milli-arcsec (which we support with multi-wavelength data). At 154
MHz we demonstrate that interstellar scintillation time-scales become long
(~decades) and have low modulation indices, whilst synchrotron driven
variability can only produce dynamic changes on time-scales of hundreds of
years, with flux density changes less than one milli-jansky (without
relativistic boosting). From this work we infer that the low frequency
extra-galactic southern sky, as seen by SKA-Low, will be non-variable on
time-scales shorter than one year.Comment: 19 pages, 11 figure
Atmospheric Input and Seasonal Inventory of Dissolved Iron in the Sargasso Sea: Implications for Iron Dynamics in Surface Waters of the Subtropical Ocean
Constraining the role of dust deposition in regulating the concentration of the essential micronutrient iron in surface ocean waters requires knowledge of the flux of seawater-soluble iron in aerosols and the replacement time of dissolved iron (DFe) in the euphotic zone. Here we estimate these quantities using seasonally resolved DFe data from the Bermuda Atlantic Time-series Study region and weekly-scale measurements of iron in aerosols and rain from Bermuda during 2019. In response to seasonal changes in vertical mixing, primary production and dust deposition, surface DFe concentrations vary from ∼0.2 nM in early spring to \u3e1 nM in late summer, with DFe inventories ranging from ∼30 to ∼80 μmol/m2, respectively, over the upper 200 m. Assuming the upper ocean approximates steady state for DFe on an annual basis, our aerosol and rainwater data require a mean euphotic-zone residence time of ∼0.8–1.9 years for DFe with respect to aeolian input
Transnasal Humidified Rapid Insufflation Ventilatory Exchange in children requiring emergent intubation (Kids THRIVE): a statistical analysis plan for a randomised controlled trial
The placement of an endotracheal tube for children with acute or critical illness is a low-frequency and high-risk procedure, associated with high rates of first-attempt failure and adverse events, including hypoxaemia. To reduce the frequency of these adverse events, the provision of oxygen to the patient during the apnoeic phase of intubation has been proposed as a method to prolong the time available for the operator to insert the endotracheal tube, prior to the onset of hypoxaemia. However, there are limited data from randomised controlled trials to validate the efficacy of this technique in children. The technique known as transnasal humidified rapid insufflation ventilatory exchange (THRIVE) uses high oxygen flow rates (approximately 2 L/kg/min) delivered through nasal cannulae during apnoea. It has been shown to at least double the amount of time available for safe intubation in healthy children undergoing elective surgery. The technique and its application in real time have not previously been studied in acutely ill or injured children presenting to the emergency department or admitted to an intensive care unit. The Kids THRIVE trial is a multicentre, international, randomised controlled trial (RCT) in children less than 16Â years old undergoing emergent intubation in either the intensive care unit or emergency department of participating hospitals. Participants will be randomised to receive either the THRIVE intervention or standard care (no apnoeic oxygenation) during their intubation. The primary objective of the trial is to determine if the use of THRIVE reduces the frequency of oxygen desaturation and increases the frequency of first-attempt success without hypoxaemia in emergent intubation of children compared with standard practice. The secondary objectives of the study are to assess the impact of the use of THRIVE on the rate of adverse events, length of mechanical ventilation and length of stay in intensive care. In this paper, we describe the detailed statistical analysis plan as an update of the previously published protocol
MWA rapid follow-up of gravitational wave transients: prospects for detecting prompt radio counterparts
We present and evaluate the prospects for detecting coherent radio
counterparts to gravitational wave (GW) events using Murchison Widefield Array
(MWA) triggered observations. The MWA rapid-response system, combined with its
buffering mode ( minutes negative latency), enables us to catch any
radio signals produced from seconds prior to hours after a binary neutron star
(BNS) merger. The large field of view of the MWA ( at
120\,MHz) and its location under the high sensitivity sky region of the
LIGO-Virgo-KAGRA (LVK) detector network, forecast a high chance of being
on-target for a GW event. We consider three observing configurations for the
MWA to follow up GW BNS merger events, including a single dipole per tile, the
full array, and four sub-arrays. We then perform a population synthesis of BNS
systems to predict the radio detectable fraction of GW events using these
configurations. We find that the configuration with four sub-arrays is the best
compromise between sky coverage and sensitivity as it is capable of placing
meaningful constraints on the radio emission from 12.6\% of GW BNS detections.
Based on the timescales of four BNS merger coherent radio emission models, we
propose an observing strategy that involves triggering the buffering mode to
target coherent signals emitted prior to, during or shortly following the
merger, which is then followed by continued recording for up to three hours to
target later time post-merger emission. We expect MWA to trigger on
BNS merger events during the LVK O4 observing run, which
could potentially result in two detections of predicted coherent emission.Comment: Accepted for publication in PAS
VAST: An ASKAP Survey for Variables and Slow Transients
The Australian Square Kilometre Array Pathfinder (ASKAP) will give us an
unprecedented opportunity to investigate the transient sky at radio
wavelengths. In this paper we present VAST, an ASKAP survey for Variables and
Slow Transients. VAST will exploit the wide-field survey capabilities of ASKAP
to enable the discovery and investigation of variable and transient phenomena
from the local to the cosmological, including flare stars, intermittent
pulsars, X-ray binaries, magnetars, extreme scattering events, interstellar
scintillation, radio supernovae and orphan afterglows of gamma ray bursts. In
addition, it will allow us to probe unexplored regions of parameter space where
new classes of transient sources may be detected. In this paper we review the
known radio transient and variable populations and the current results from
blind radio surveys. We outline a comprehensive program based on a multi-tiered
survey strategy to characterise the radio transient sky through detection and
monitoring of transient and variable sources on the ASKAP imaging timescales of
five seconds and greater. We also present an analysis of the expected source
populations that we will be able to detect with VAST.Comment: 29 pages, 8 figures. Submitted for publication in Pub. Astron. Soc.
Australi
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