137 research outputs found
Seasat data utilization project
During the three months of orbital operations, the satellite returned data from the world's oceans. Dozens of tropical storms, hurricanes and typhoons were observed, and two planned major intensive surface truth experiments were conducted. The utility of the Seasat-A microwave sensors as oceanographic tools was determined. Sensor and geophysical evaluations are discussed, including surface observations, and evaluation summaries of an altimeter, a scatterometer, a scanning multichannel microwave radiometer, a synthetic aperture radar, and a visible and infrared radiometer
Leaving no-one behind? Social inequalities and contrasting development impacts in rural Rwanda
Two polar viewpoints have emerged regarding Rwanda’s post-genocide development: (1) that economic development has improved the wellbeing of Rwandans and (2) that repressive policies have negatively impacted many. Assessing the impacts and inclusiveness of policies through trends among different social groups is timely in the context of the Sustainable Development Goals’ pledge to ‘leave no-one behind’. This study examines rural Rwandans’ perspectives on the changes affecting them. A multidimensional wellbeing approach was applied through mixed-method research involving 115 rural households in two locations in western Rwanda, in 2011–12. Findings reveal that the household-level impact was heavily influenced by socio-economic power and socio-ethnic grouping. Negative impacts, including restricted freedom and loss of material and cultural resources are disproportionately felt by the poorest. The indigenous Batwa suffer particularly detrimental impacts. The findings suggest that strategies deemed successful in making progress towards the Millennium Development Goals in Rwanda need, as a minimal measure, to be supported by social protection programs that specifically target the landless, vulnerable and cultural minorities. However, to align Rwanda’s development policies with the ambitions of the Sustainable Development Goals (SDGs), a dramatic strategic shift is required to ‘leave no-one behind’ and avoid the reproduction of poverty and exacerbation of inequality
The coronal line regions of planetary nebulae NGC6302 and NGC6537: 3-13um grating and echelle spectroscopy
We report on advances in the study of the cores of NGC6302 and NGC6537 using
infrared grating and echelle spectroscopy. In NGC6302, emission lines from
species spanning a large range of ionization potential, and in particular
[SiIX]3.934um, are interpreted using photoionization models (including CLOUDY),
which allow us to reestimate the central star's temperature to be about
250000K. All of the detected lines are consistent with this value, except for
[AlV] and [AlVI]. Aluminium is found to be depleted to one hundredth of the
solar abundance, which provides further evidence for some dust being mixed with
the highly ionized gas (with photons harder than 154eV). A similar depletion
pattern is observed in NGC6537. Echelle spectroscopy of IR coronal ions in
NGC6302 reveals a stratified structure in ionization potential, which confirms
photoionization to be the dominant ionization mechanism. The lines are narrow
(< 22km/s FWHM), with no evidence of the broad wings found in optical lines
from species with similar ionization potentials, such as [NeV]3426A. We note
the absence of a hot bubble, or a wind blown bipolar cavity filled with a hot
plasma, at least on 1'' and 10km/s scales. We also provide accurate new
wavelengths for several of the infrared coronal lines observed with the
echelle.Comment: Accepted for publication in MNRA
A 3D Photoionization Model of the Extreme Planetary Nebula NGC 6302
We present a 3D photoionization model of the PN NGC 6302, one of the most
complex objects of its kind. Our Mocassin model is composed of an extremely
dense circumstellar disk and a large pair of diffuse bipolar lobes, a
combination necessary to reproduce the observed spectrum. The masses of these
components gives a total nebular mass of 4.7Mo. Discrepancies between our model
fit and the observations are attributed to complex density inhomogeneities in
the nebula. The potential to resolve such discrepancies with more complex
models is confirmed by a range of models introducing small-scale structures.
Compared to solar abundances He is enhanced by 50%, C is slightly subsolar, O
is solar, and N is enhanced by a factor of 6. These imply a significant 3rd
dredge-up coupled with hot-bottom burning CN-cycle conversion of dredged-up C
to N.
The central star is partly obscured by the edge-on circumstellar disk and its
properties are not well constrained. Emission from a number of high-ionization
`coronal' lines provides constraints on the form of the high-energy ionizing
flux. Using a solar abundance stellar atmosphere we are unable to fit all of
the observed line fluxes, but a substantially better fit was obtained using a
220,000K H-deficient stellar atmosphere with L*=14,300 Lo. The H-deficient
nature of the central star suggests it has undergone a late thermal pulse, and
fits to evolutionary tracks imply a central star mass of 0.73-0.82Mo.
Timescales for these tracks suggest the object left the top of the AGB ~2100
years ago, in agreement with studies of the recent mass-loss event that formed
the bipolar lobes. Based on the modelled nebular and central star masses we
estimate the initial mass of the central star to be 5.5Mo, in agreement with
that derived from evolutionary tracks.
(Abstract truncated)Comment: 23 pages, 8 figures, 10 tables. Accepted for publication in MNRA
Recommended from our members
Intrinsic radiolabeling of nutrients for human nutrition studies using accelerator mass spectrometry
Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. III - Further observations of NGC 5548 at optical wavelengths
The results of the second year of an intensive ground-based spectroscopic and photometric study of variability in the bright Seyfert 1 galaxy NGC 5548 are reported in order to study the relationship between continuum and emission-line variability. Relative to the first year of the monitoring program, the nucleus of NGC 5548 was considerably fainter and the continuum variations slower during the second year, but the continuum H-beta cross-correlation results for the two years are nearly identical. The variations in the broad H-beta emission-line lag behind those in the continuum by somewhat less than 20 days, as concluded from the first year's dat
First amyloid β1-42 certified reference material for re-calibrating commercial immunoassays
INTRODUCTION: Reference materials based on human cerebrospinal fluid were certified for the mass concentration of amyloid beta (Aβ)1-42 (Aβ42 ). They are intended to be used to calibrate diagnostic assays for Aβ42 . METHODS: The three certified reference materials (CRMs), ERM-DA480/IFCC, ERM-DA481/IFCC and ERM-DA482/IFCC, were prepared at three concentration levels and characterized using isotope dilution mass spectrometry methods. Roche, EUROIMMUN, and Fujirebio used the three CRMs to re-calibrate their immunoassays. RESULTS: The certified Aβ42 mass concentrations in ERM-DA480/IFCC, ERM-DA481/IFCC, and ERM-DA482/IFCC are 0.45, 0.72, and 1.22 μg/L, respectively, with expanded uncertainties (k = 2) of 0.07, 0.11, and 0.18 μg/L, respectively. Before re-calibration, a good correlation (Pearson's r > 0.97), yet large biases, were observed between results from different commercial assays. After re-calibration the between-assay bias was reduced to < 5%. DISCUSSION: The Aβ42 CRMs can ensure the equivalence of results between methods and across platforms for the measurement of Aβ42
Heterogeneity of pollen food allergy syndrome in seven Southern European countries: The @IT.2020 multicenter study
Background Pollen food allergy syndrome (PFAS) is a frequently underdiagnosed disease due to diverse triggers, clinical presentations, and test results. This is especially relevant in geographic areas with a broad spectrum of pollen sensitization, such as Southern Europe. Objectives To elucidate similarities and differences of PFAS in nine Southern European centers and identify associated characteristics and unique markers of PFAS. Methods As part of the @IT.2020 Multicenter Study, 815 patients with seasonal allergic rhinitis (SAR), aged 10-60 years, were recruited in seven countries. They completed questionnaires regarding SAR, comorbidities, family history, and PFAS, and underwent skin prick testing (SPT) and serum IgE testing. Results Of the 815 patients, 167 (20.5%) reported PFAS reactions. Most commonly, eliciting foods were kiwi (58, 34.7%), peach (43, 25.7%), and melon (26, 15.6%). Reported reactions were mostly local (216/319, 67.7%), occurring within 5 min of contact with elicitors (209/319, 65.5%). Associated characteristics included positive IgE to at least one panallergen (profilin, PR-10, or nsLTP) (p = 0.007), maternal PFAS (OR: 3.716, p = 0.026), and asthma (OR: 1.752, p = 0.073). Between centers, heterogeneity in prevalence (Marseille: 7.5% vs. Rome: 41.4%, p < 0.001) and of clinical characteristics was apparent. Cypress played a limited role, with only 1/22 SPT mono-sensitized patients reporting a food reaction (p < 0.073). Conclusions PFAS is a frequent comorbidity in Southern European SAR patients. Significant heterogeneity of clinical characteristics in PFAS patients among the centers was observed and may be related to the different pollen sensitization patterns in each geographic area. IgE to panallergen(s), maternal PFAS, and asthma could be PFAS-associated characteristics
Statistics versus livelihoods: questioning Rwanda’s pathway out of poverty
Recent statistics indicate that poverty in Rwanda decreased impressively between 2006 and 2014. This seems to confirm Rwanda’s developmental progress. This article however argues for a more cautious interpretation of household survey data. The authors contrast macro-level statistical analysis with in-depth field research on livelihood conditions. Macro-economic numbers provide interesting information, however differentiated evidence is required to understand how poverty ‘works’ in everyday life. On the basis of the Rwandan case study, the authors conclude that because of the high political stakes of data collection and analysis, and given that relations of power influence the production of knowledge on poverty, cross-checking is crucial
- …