1,060 research outputs found
Simulations of atmospheric methane for Cape Grim, Tasmania, to constrain southeastern Australian methane emissions
This study uses two climate models and six scenarios of prescribed methane emissions to compare modelled and observed atmospheric methane between 1994 and 2007, for Cape Grim, Australia (40.7° S, 144.7° E). The model simulations follow the TransCom-CH4 protocol and use the Australian Community Climate and Earth System Simulator (ACCESS) and the CSIRO Conformal-Cubic Atmospheric Model (CCAM). Radon is also simulated and used to reduce the impact of transport differences between the models and observations. Comparisons are made for air samples that have traversed the Australian continent. All six emission scenarios give modelled concentrations that are broadly consistent with those observed. There are three notable mismatches, however. Firstly, scenarios that incorporate interannually varying biomass burning emissions produce anomalously high methane concentrations at Cape Grim at times of large fire events in southeastern Australia, most likely due to the fire methane emissions being unrealistically input into the lowest model level. Secondly, scenarios with wetland methane emissions in the austral winter overestimate methane concentrations at Cape Grim during wintertime while scenarios without winter wetland emissions perform better. Finally, all scenarios fail to represent a~methane source in austral spring implied by the observations. It is possible that the timing of wetland emissions in the scenarios is incorrect with recent satellite measurements suggesting an austral spring (SeptemberâOctoberâNovember), rather than winter, maximum for wetland emissions. Š Author(s) 2015
Radon: a universal baseline indicator at sites with contrasting physical settings
The primary goal of World Meteorological Organisation Global Atmosphere Watch (WMOâGAW) baseline stations is systematic global monitoring of chemical composition of the atmosphere, requiring a reliable, consistent and unambiguous approach for the identification of baseline air. Premier stations in the GAW baseline network span a
broad range of physical settings, from remote marine to highâaltitude continental sites, necessitating carefully tailored
siteâspecific requirements for baseline sampling, data selection, and analysis. Radonâ222 is a versatile and unambiguous terrestrial tracer, widelyâused in transport and mixing studies. Since the majority of anthropogenic pollution sources also have terrestrial origins, radon has become a popular addition to the âbaseline selection
toolkitâ at numerous GAW stations as a proxy for âpollution potentialâ. In the past, detector performance and postprocessing
methods necessitated the adoption of a relaxed (e.g. 100 mBq mâ3) radon threshold for minimal terrestrial influence, intended to be used in conjunction with other baseline criteria and analysis procedures, including wind speed, wind direction, particle number, outlier rejection and filtering. However, recent improvements in detector sensitivity, stability and postâprocessing procedures have reduced detection limits below 10 mBq mâ3 at Cape Grim and to ďž25 mBq mâ3 at other baseline stations. Consequently, for suitably sensitive instruments (such as the ANSTO designed and built twoâfilter dualâflowâloop detectors), radon concentrations alone can be used to unambiguously identify air masses that have been removed from terrestrial sources (at altitude or over ice), or in equilibrium
with the ocean surface, for periods of >2â3 weeks (radon ⤠40 mBq mâ3). Potentially, radon observations alone can thus provide a consistent and universal (site independent) means for baseline identification. Furthermore, for continental sites with complex topography and meteorology, where true âbaselineâ conditions may never
occur, radon can be used to indicate the least terrestriallyâperturbed air masses, and provide a means by which to apply limits to the level of âacceptable terrestrial influenceâ for a given application. We demonstrate the efficacy of the radonâbased selection at a range of sites in contrasting physical settings, including: Cape Grim (Tasmania), Cape Point (South Africa), Mauna Loa (Hawaii), Jungfraujoch (Switzerland) and Schneefernerhaus (Germany).Bureau of Meteorology and CSIRO Oceans and Atmosphere,Climate Science Centre
Biomimetic knee design to improve joint torque and life for bipedal robotics
Š Springer International Publishing AG, part of Springer Nature 2018. This paper details the design, construction, and performance analysis of a biologically inspired knee joint for use in bipedal robotics. The design copies the condylar surfaces of the distal end of the femur and utilizes the same crossed four-bar linkage design the human knee uses. The joint includes a changing center of rotation, a screw-home mechanism, and patella; these are characteristics of the knee that are desirable to copy for bipedal robotics. The design was calculated to have an average sliding to rolling ratio of 0.079, a maximum moment arm of 2.7 in and a range of motion of 151°. This should reduce wear and perform similar to the human knee. Prototypes of the joint have been created to test these predicted properties
Towards a universal âbaselineâ characterisation of air masses for high- and low-altitude observing stations using Radon-222
We demonstrate the ability of atmospheric radon concentrations to reliably and unambiguously identify local and
remote terrestrial influences on an air mass, and thereby the potential for alteration of trace gas composition by
anthropogenic and biogenic processes. Based on high accuracy (lower limit of detection 10â40 mBq mâ3), high temporal
resolution (hourly) measurements of atmospheric radon concentration we describe, apply and evaluate a simple two-step
method for identifying and characterising constituent mole fractions in baseline air. The technique involves selecting a
radon-based threshold concentration to identify the âcleanestâ (least terrestrially influenced) air masses, and then
performing an outlier removal step based on the distribution of constituent mole fractions in the identified clean air
masses. The efficacy of this baseline selection technique is tested at three contrasting WMO GAW stations: Cape Grim (a
coastal low-altitude site), Mauna Loa (a remote high-altitude island site), and Jungfraujoch (a continental high-altitude
site). At Cape Grim and Mauna Loa the two-step method is at least as effective as more complicated methods employed to
characterise baseline conditions, some involving up to nine steps. While it is demonstrated that Jungfraujoch air masses
rarely meet the baseline criteria of the more remote sites, a selection method based on a variable monthly radon threshold
is shown to produce credible ânear baselineâ characteristics. The seasonal peak-to-peak amplitude of recent monthly
baseline CO2 mole fraction deviations from the long-term trend at Cape Grim, Mauna Loa and Jungfraujoch are estimated
to be 1.1, 6.0 and 8.1 ppm, respectively
Speculation on the origin of sub-baseline excursions of CH4 at Cape Grim
The Advanced Global Atmospheric Gases Experiment (AGAGE) program has historically measured in situ
methane (CH4
) at Cape Grim via gas chromatography with flame ionization detection (GC-FID) in 40 minutely
grab samples. By adding continuous, high precision in situ measurements of CH4
(Picarro cavity ring-down
spectroscopy [CRDS]) at both Cape Grim, Tasmania, and Casey, Antarctica, a new feature has become apparent
in the Cape Grim CH4
record. During the austral summer (December to February), the Cape Grim CH4
record
periodically drops below baseline. For example, in Figure 1, a number of sustained episodes of depressed CH4
concentration can be seen below the baseline selected data shown in red. Notably, these episodes are also seen
in the GC-FID record.
In this presentation, we examine these sub-baseline excursions of CH4
. In conjunction with meteorology and a
variety of other chemical species measured at Cape Grim, including radon, ozone, hydrogen and ethane, we speculate on a number of possible mechanisms that might be responsible for these dips in CH4 mixing ratio
Multiwavelength monitoring and X-ray brightening of Be X-ray binary PSR J2032+4127/MT91 213 on its approach to periastron
The radio and gamma-ray pulsar PSR J2032+4127 was recently found to be in a decades-long orbit with the Be star MT91 213, with the pulsar moving rapidly towards periastron. This binary shares many similar characteristics with the previously unique binary system PSR B1259â63/LS 2883. Here, we describe radio, X-ray, and optical monitoring of PSR J2032+4127/MT91 213. Our extended orbital phase coverage in radio, supplemented with Fermi LAT gamma-ray data, allows us to update and refine the orbital period to 45â50 yr and time of periastron passage to 2017 November. We analyse archival and recent Chandra and Swift observations and show that PSR J2032+4127/MT91 213 is now brighter in X-rays by a factor of âź70 since 2002 and âź20 since 2010. While the pulsar is still far from periastron, this increase in X-rays is possibly due to collisions between pulsar and Be star winds. Optical observations of the HÎą emission line of the Be star suggest that the size of its circumstellar disc may be varying by âź2 over time-scales as short as 1â2 months. Multiwavelength monitoring of PSR J2032+4127/MT91 213 will continue through periastron passage, and the system should present an interesting test case and comparison to PSR B1259â63/LS 2883
Phase 1, pharmacogenomic, dose-expansion study of pegargiminase plus pemetrexed and cisplatin in patients with ASS1-deficient non-squamous non-small cell lung cancer
Introduction
We evaluated the arginine-depleting enzyme pegargiminase (ADI-PEG20; ADI) with pemetrexed (Pem) and cisplatin (Cis) (ADIPemCis) in ASS1-deficient non-squamous non-small cell lung cancer (NSCLC) via a phase 1 dose-expansion trial with exploratory biomarker analysis.
Methods
Sixty-seven chemonaĂŻve patients with advanced non-squamous NSCLC were screened, enrolling 21 ASS1-deficient subjects from March 2015 to July 2017 onto weekly pegargiminase (36 mg/m2) with Pem (500 mg/m2) and Cis (75 mg/m2), every 3 weeks (four cycles maximum), with maintenance Pem or pegargiminase. Safety, pharmacodynamics, immunogenicity, and efficacy were determined; molecular biomarkers were annotated by next-generation sequencing and PD-L1 immunohistochemistry.
Results
ADIPemCis was well-tolerated. Plasma arginine and citrulline were differentially modulated; pegargiminase antibodies plateaued by week 10. The disease control rate was 85.7% (n = 18/21; 95% CI 63.7%â97%), with a partial response rate of 47.6% (n = 10/21; 95% CI 25.7%â70.2%). The median progression-free and overall survivals were 4.2 (95% CI 2.9â4.8) and 7.2 (95% CI 5.1â18.4) months, respectively. Two PD-L1-expressing (âĽ1%) patients are alive following subsequent pembrolizumab immunotherapy (9.5%). Tumoral ASS1 deficiency enriched for p53 (64.7%) mutations, and numerically worse median overall survival as compared to ASS1-proficient disease (10.2 months; n = 29). There was no apparent increase in KRAS mutations (35.3%) and PD-L1 (<1%) expression (55.6%). Re-expression of tumoral ASS1 was detected in one patient at progression (n = 1/3).
Conclusions
ADIPemCis was safe and highly active in patients with ASS1-deficient non-squamous NSCLC, however, survival was poor overall. ASS1 loss was co-associated with p53 mutations. Therapies incorporating pegargiminase merit further evaluation in ASS1-deficient and treatment-refractory NSCLC
The semicentennial binary system PSR J2032+4127 at periastron: X-ray photometry, optical spectroscopy, and SPH modelling
X-ray photometry and optical spectra are presented covering the periastron passage of the highly eccentric, âź50âyr binary system PSR J2032+4127 in 2017 November. This system consists of a 143âms pulsar in orbit around a massive OB star, MT 91-213. The data show dramatic changes during the encounter as the pulsar wind collided with the stellar wind. The X-ray flux rose on the approach to periastron, then underwent a major dip in the few days around periastron, and then gradually declined over the next few weeks. The optical spectroscopy revealed a steady decline in the HâÎą line strength on the approach to periastron (from an equivalent width of â15 to â7âĂ
) implying a truncation of the OB starâs circumstellar disc by the approaching neutron star. Smooth particle hydrodynamic modelling is used here to model the system within the context of the observed behaviour and predict the geometrical configuration of the circumstellar disc with respect to the pulsarâs orbit
Tracking Subtle Stereotypes of Children with Trisomy 21: From Facial-Feature-Based to Implicit Stereotyping
Background: Stigmatization is one of the greatest obstacles to the successful integration of people with Trisomy 21 (T21 or Down syndrome), the most frequent genetic disorder associated with intellectual disability. Research on attitudes and stereotypes toward these people still focuses on explicit measures subjected to social-desirability biases, and neglects how variability in facial stigmata influences attitudes and stereotyping. Methodology/Principal Findings: The participants were 165 adults including 55 young adult students, 55 non-student adults, and 55 professional caregivers working with intellectually disabled persons. They were faced with implicit association tests (IAT), a well-known technique whereby response latency is used to capture the relative strength with which some groups of peopleâhere photographed faces of typically developing children and children with T21âare automatically (without conscious awareness) associated with positive versus negative attributes in memory. Each participant also rated the same photographed faces (consciously accessible evaluations). We provide the first evidence that the positive bias typically found in explicit judgments of children with T21 is smaller for those whose facial features are highly characteristic of this disorder, compared to their counterparts with less distinctive features and to typically developing children. We also show that this bias can coexist with negative evaluations at the implicit level (with large effect sizes), even among professional caregivers
Large cell neuroendocrine lung carcinoma: consensus statement from The British Thoracic Oncology Group and the Association of Pulmonary Pathologists
Over the past 10 years, lung cancer clinical and translational research has been characterised by exponential progress, exemplified by the introduction of molecularly targeted therapies, immunotherapy and chemo-immunotherapy combinations to stage III and IV non-small cell lung cancer. Along with squamous and small cell lung cancers, large cell neuroendocrine carcinoma (LCNEC) now represents an area of unmet need, particularly hampered by the lack of an encompassing pathological definition that can facilitate real-world and clinical trial progress. The steps we have proposed in this article represent an iterative and rational path forward towards clinical breakthroughs that can be modelled on success in other lung cancer pathologies
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