243 research outputs found
Modelling Ash Fall and Debris Flow Hazards of Mt Erebus, Antarctica
Mt Erebus is a volcano in the Ross Sea that has been active since its first sighting in 1841 by Captain
James Clark Ross. It consistently maintains an eruption plume and convecting lava lake of phonolitic
composition, and regularly erupts as minor strombolian events. Prior to observations of Erebus
beginning, major eruption events have occurred, with 2 plinian eruptions depositing ash up to
200km from the vent, and >43 eruptions depositing ash at least 7-12km from source. Using this
information, three volcanic eruptions are modelled to predict ash fall using various wind speeds, and
assuming an eruption plume of 7000m, and an erupted mass of 1x1010kg. It is observed that debris
flows will most likely follow glacier paths as these already follow the lowest topographical route,
while the eruption modelled with have little impact on Scott Base or McMurdo Station, unless
optimal wind conditions occur
Development of a behavioural welfare assessment tool for routine use with captive elephants
There has been much concern in recent years about the welfare of elephants in zoos across North America and Europe. While some previous studies have assessed captive elephant welfare at a particular point in time, there has been little work to develop methods which could be used for regular, routine welfare assessment. Such assessment is important in order to track changes in welfare over time. A welfare assessment tool should be rapid, reliable, and simple to complete, without requiring specialist training and facilities; welfare assessments based on behavioural observations are well suited to this purpose. This report describes the development of a new elephant behavioural welfare assessment tool designed for routine use by elephant keepers. Tool development involved: (i) identification of behavioural indicators of welfare from the literature and from focus groups with relevant stakeholders; (ii) development of a prototype tool; (iii) testing of the tool at five UK zoological institutions, involving 29 elephants (representing 46% of the total UK captive elephant population of 63 animals); (iv) assessment of feasibility and reliability of aspects of the prototype tool; (v) assessment of the validity of each element of the tool to reflect the relevant behaviour by comparing detailed behavioural observations with data from the prototype tool; (vi) assessment of known-groups criterion validity by comparing prototype tool scores in individuals with demographics associated with better or worse welfare; (vii) development of a finalised tool which incorporated all elements of the tool which met the criteria set for validity and reliability. Elements of the tool requiring further consideration are discussed, as are considerations for appropriate application and interpretation of scores. This novel behavioural welfare assessment tool can be used by elephant-holding facilities for routine behavioural welfare monitoring, which can inform adjustments to individual welfare plans for each elephant in their collection, to help facilities further assess and improve captive elephant welfare. This study provides an example of how an evidence-based behavioural welfare assessment tool for use by animal caretakers can be developed within the constraints of zoo-based research, which could be applied to a range of captive species
Understanding Degassing Pathways Along the 1886 Tarawera (New Zealand) Volcanic Fissure by Combining Soil and Lake CO₂ Fluxes
CO₂ flux measurements are often used to monitor volcanic systems, understand the cause of volcanic unrest, and map sub-surface structures. Currently, such measurements are incomplete at Tarawera (New Zealand), which erupted with little warning in 1886 and produced a ∼17 km long fissure. We combine new soil CO₂ flux and C isotope measurements of Tarawera with previous data from Rotomahana and Waimangu (regions also along the 1886 fissure) to fingerprint the CO₂ source, understand the current pathways for degassing, quantify the CO₂ released along the entire fissure, and provide a baseline survey. The total CO₂ emissions from the fissure are 1227 t⋅d⁻¹ (742–3398 t⋅d⁻¹ 90 % confidence interval), similar to other regions in the Taupō Volcanic Zone. The CO₂ flux from Waimangu and Rotomahana is far higher than from Tarawera (>549 vs. ∼4 t⋅d⁻¹ CO₂), likely influenced by a shallow silicic body at depth and Okataina caldera rim faults increasing permeability at the southern end of the fissure. Highly localized regions of elevated CO2 flux occur along the fissure and are likely caused by cross-cutting faults that focus the flow. One of these areas occurs on Tarawera, which is emitting ∼1 t⋅d⁻¹ CO₂ with a δ¹³CO₂ of −5.5 ± 0.5 ‰, and comparison with previous observations shows that activity is declining over time. This region highlights the spatial and temporal complexity of degassing pathways at volcanoes and that sub-surface structures exert a primary control on the magnitude of CO₂ flux in comparison to the surface mechanism (i.e., CO₂ released through the soil or lake surface)
Equilibration in the Aftermath of the Lunar-Forming Giant Impact
Simulations of the moon-forming impact suggest that most of the lunar
material derives from the impactor rather than the Earth. Measurements of lunar
samples, however, reveal an oxygen isotope composition that is
indistinguishable from terrestrial samples, and clearly distinct from
meteorites coming from Mars and Vesta. Here we explore the possibility that the
silicate Earth and impactor were compositionally distinct with respect to
oxygen isotopes, and that the terrestrial magma ocean and lunar-forming
material underwent turbulent mixing and equilibration in the energetic
aftermath of the giant impact. This mixing may arise in the molten disk epoch
between the impact and lunar accretion, lasting perhaps 10^2-10^3 yr. The
implications of this idea for the geochemistry of the Moon, the origin of water
on Earth, and constraints on the giant impact are discussed.Comment: 34 pages, 5 figure
Randomised controlled trial of paracetamol or ibuprofen, as required for fever and pain in the first year of life, for prevention of asthma at age 6 years : paracetamol or ibuprofen in the primary prevention of asthma in Tamariki (PIPPA Tamariki) protocol
Introduction Asthma is one of the most common diseases in the world and is a global public health burden. There is an urgent need for research that leads to evidenced-based primary prevention strategies to reduce the prevalence of asthma. One novel risk factor that might have a role in the pathogenesis of asthma is the use of paracetamol in early life. This trial aims to determine if paracetamol, compared with ibuprofen use, as required for fever and pain in the first year of life, increases the risk of asthma at age 6 years. Methods and analysis The Paracetamol and Ibuprofen in Primary Prevention of Asthma in Tamariki trial is a multicentre, open-label, two-Arm parallel randomised controlled trial. 3922 infants born at ≥32 weeks' gestation will be randomly allocated to receive only paracetamol or only ibuprofen for treatment of fever and pain, if required in the first year of life. The primary outcome is asthma at 6 years of age, defined as the presence of wheeze in the preceding 12 months. Secondary outcomes include hospital admissions for bronchiolitis, wheeze or asthma in the first year of life, and within the first 6 years of life; wheeze at 3 years of age; eczema within the first year and at 3 and 6 years of age; atopy at 3 and 6 years of age. Ethics and dissemination The trial has been approved by the Northern A Health and Disability Ethics Committee of New Zealand (17/NTA/233). Dissemination plans include publication in international peer-reviewed journals, and presentation at national and international scientific meetings, assimilation into national and international guidelines, and presentation of findings to lay audiences through established media links. Trial registration number ACTRN12618000303246; Pre-results
Characterizing K2 planet discoveries : a super-Earth transiting the bright K dwarf HIP 116454
We report the first planet discovery from the two-wheeled Kepler (K2) mission: HIP 116454 b. The host star HIP 116454 is a bright (V = 10.1, K = 8.0) K1 dwarf with high proper motion and a parallax-based distance of 55.2 ± 5.4 pc. Based on high-resolution optical spectroscopy, we find that the host star is metal-poor with [Fe/H] =–0.16 ± 0.08 and has a radius R = 0.716 ± 0.024 R ☉ and mass M = 0.775 ± 0.027 M ☉. The star was observed by the Kepler spacecraft during its Two-Wheeled Concept Engineering Test in 2014 February. During the 9 days of observations, K2 observed a single transit event. Using a new K2 photometric analysis technique, we are able to correct small telescope drifts and recover the observed transit at high confidence, corresponding to a planetary radius of pR = 2.53 ± 0.18 R ⊕. Radial velocity observations with the HARPS-N spectrograph reveal a 11.82 ± 1.33 M ⊕ planet in a 9.1 day orbit, consistent with the transit depth, duration, and ephemeris. Follow-up photometric measurements from the MOST satellite confirm the transit observed in the K2 photometry and provide a refined ephemeris, making HIP 116454 b amenable for future follow-up observations of this latest addition to the growing population of transiting super-Earths around nearby, bright stars.Publisher PDFPeer reviewe
Characterizing K2 planet discoveries: a super-Earth transiting the bright K dwarf HIP 116454
Publisher's version/PDFWe report the first planet discovery from the two-wheeled Kepler (K2) mission: HIP 116454 b. The host star HIP 116454 is a bright (V = 10.1, K = 8.0) K1 dwarf with high proper motion and a parallax-based distance of 55.2 [plus or minus] 5.4 pc. Based on high-resolution optical spectroscopy, we find that the host star is metal-poor with [Fe/H] = −0.16 [plus or minus] 0.08 and has a radius R[subscript star] = 0.716 [plus or minus] 0.024 R[subscript circled dot] and mass M[subscript star] = 0.775 [plus or minus] 0.027 M[subscript circled dot]. The star was observed by the Kepler spacecraft during its Two-Wheeled Concept Engineering Test in 2014 February. During the 9 days of observations, K2 observed a single transit event. Using a new K2 photometric analysis technique, we are able to correct small telescope drifts and recover the observed transit at high confidence, corresponding to a planetary radius of R[subscript p] = 2.53 [plus or minus] 0.18 R[subscript circled plus]. Radial velocity observations with the HARPS-N spectrograph reveal a 11.82 [plus or minus] 1.33 M[subscript circled plus] planet in a 9.1 day orbit, consistent with the transit depth, duration, and ephemeris. Follow-up photometric measurements from the MOST satellite confirm the transit observed in the K2 photometry and provide a refined ephemeris, making HIP 116454 b amenable for future follow-up observations of this latest addition to the growing population of transiting super-Earths around nearby, bright stars
High concentrations and turnover rates of DMS, DMSP and DMSO in Antarctic sea ice
Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 38 (2011): L23609, doi:10.1029/2011GL049712.The vast Antarctic sea-ice zone (SIZ) is a potentially significant source of the climate-active gas dimethylsulfide (DMS), yet few data are available on the concentrations and turnover rates of DMS and the related compounds dimethylsulfoniopropionate (DMSP) and dimethylsulfoxide (DMSO) in sea ice environments. Here we present new measurements characterizing the spatial variability of DMS, DMSP, and DMSO concentrations across the Antarctic SIZ, and results from tracer experiments quantifying the production rates of DMS from various sources. We observed extremely high concentrations (>200 nM) and turnover rates (>100 nM d−1) of DMS in sea-ice brines, indicating intense cycling of DMS/P/O. Our results demonstrate a previously unrecognized role for DMSO reduction as a major pathway of DMS production in Antarctic sea ice.This work was supported in part by Woods Hole Oceanographic
Institution’s Ocean Life Institute and by NSF grant ANT-0838872 to KRA.2012-06-1
The genomes of two key bumblebee species with primitive eusocial organization
Background: The shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there is widespread concern over recent population declines in some species. High-quality genomic data will inform key aspects of bumblebee biology, including susceptibility to implicated population viability threats. Results: We report the high quality draft genome sequences of Bombus terrestris and Bombus impatiens, two ecologically dominant bumblebees and widely utilized study species. Comparing these new genomes to those of the highly eusocial honeybee Apis mellifera and other Hymenoptera, we identify deeply conserved similarities, as well as novelties key to the biology of these organisms. Some honeybee genome features thought to underpin advanced eusociality are also present in bumblebees, indicating an earlier evolution in the bee lineage. Xenobiotic detoxification and immune genes are similarly depauperate in bumblebees and honeybees, and multiple categories of genes linked to social organization, including development and behavior, show high conservation. Key differences identified include a bias in bumblebee chemoreception towards gustation from olfaction, and striking differences in microRNAs, potentially responsible for gene regulation underlying social and other traits. Conclusions: These two bumblebee genomes provide a foundation for post-genomic research on these key pollinators and insect societies. Overall, gene repertoires suggest that the route to advanced eusociality in bees was mediated by many small changes in many genes and processes, and not by notable expansion or depauperation
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