405 research outputs found
EUV Spectra of the Full Solar Disk: Analysis and Results of the Cosmic Hot Interstellar Plasma Spectrometer (CHIPS)
We analyze EUV spectra of the full solar disk from the Cosmic Hot
Interstellar Plasma Spectrometer (CHIPS) spanning a period of two years. The
observations were obtained via a fortuitous off-axis light path in the 140 --
270 Angstrom passband. The general appearance of the spectra remained
relatively stable over the two-year time period, but did show significant
variations of up to 25% between two sets of Fe lines that show peak emission at
1 MK and 2 MK. The variations occur at a measured period of 27.2 days and are
caused by regions of hotter and cooler plasma rotating into, and out of, the
field of view. The CHIANTI spectral code is employed to determine plasma
temperatures, densities, and emission measures. A set of five isothermal
plasmas fit the full disk spectra well. A 1 -- 2 MK plasma of Fe contributes
85% of the total emission in the CHIPS passband. The standard Differential
Emission Measures (DEMs) supplied with the CHIANTI package do not fit the CHIPS
spectra well as they over-predict emission at temperatures below log(T) = 6.0
and above log(T) = 6.3. The results are important for cross-calibrating TIMED,
SORCE, SOHO/EIT, and CDS/GIS, as well as the recently launched Solar Dynamics
Observatory.Comment: 27 Pages, 13 Figure
UK Stratigraphical Framework Series : Oxford Clay Formation
This report forms part of the UK Stratigraphical Framework Series (UKSFS) and provides an overview of the stratigraphy of the Oxford Clay of southern and eastern England. The work covers both outcrop and subcrop areas and is primarily based on new interpretations of borehole geophysical log and core sample data with reference to published materials and outcrop sections as required. The emphasis of the report is on regional structure, thickness and facies trends in the Oxford Clay Formation. It should provide a framework for site-specific geological investigations that require understanding of the Oxford Clay Formation
Tasmanian devil CD28 and CTLA4 capture CD80 and CD86 from adjacent cells
Immune checkpoint immunotherapy is a pillar of human oncology treatment with potential for non-human species. The first checkpoint immunotherapy approved for human cancers targeted the CTLA4 protein. CTLA4 can inhibit T cell activation by capturing and internalizing CD80 and CD86 from antigen presenting cells, a process called trans-endocytosis. Similarly, CD28 can capture CD80 and CD86 via trogocytosis and retain the captured ligands on the surface of the CD28-expressing cells. The wild Tasmanian devil (Sarcophilus harrisii) population has declined by 77% due to transmissible cancers that evade immune defenses despite genetic mismatches between the host and tumors. We used a live cell-based assay to demonstrate that devil CTLA4 and CD28 can capture CD80 and CD86. Mutation of evolutionarily conserved motifs in CTLA4 altered functional interactions with CD80 and CD86 in accordance with patterns observed in other species. These results suggest that checkpoint immunotherapies can be translated to evolutionarily divergent species.</p
A novel system to map protein interactions reveals evolutionarily conserved immune evasion pathways on transmissible cancers
Around 40% of humans and Tasmanian devils (Sarcophilus harrisii) develop cancer in their lifetime, compared to less than 10% for most species. In addition, devils are affected by two of the three known transmissible cancers in mammals. Immune checkpoint immunotherapy has transformed human medicine, but a lack of species-specific reagents has limited checkpoint immunology in most species. We developed a cut-and-paste reagent development system and used the fluorescent fusion protein system to show that immune checkpoint interactions are conserved across 160,000,000 years of evolution, CD200 is highly expressed on transmissible tumor cells, and coexpression of CD200R1 can block CD200 surface expression. The system’s versatility across species was demonstrated by fusing a fluorescent reporter to a camelid-derived nanobody that binds human programmed death ligand 1. The evolutionarily conserved pathways suggest that naturally occurring cancers in devils and other species can be used to advance our understanding of cancer and immunological tolerance.</p
Unveiling Soft Gamma-Ray Repeaters with INTEGRAL
Thanks to INTEGRAL's long exposures of the Galactic Plane, the two brightest
Soft Gamma-Ray Repeaters, SGR 1806-20 and SGR 1900+14, have been monitored and
studied in detail for the first time at hard-X/soft gamma rays.
This has produced a wealth of new scientific results, which we will review
here. Since SGR 1806-20 was particularly active during the last two years, more
than 300 short bursts have been observed with INTEGRAL. and their
characteristics have been studied with unprecedented sensitivity in the 15-200
keV range. A hardness-intensity anticorrelation within the bursts has been
discovered and the overall Number-Intensity distribution of the bursts has been
determined. In addition, a particularly active state, during which ~100 bursts
were emitted in ~10 minutes, has been observed on October 5 2004, indicating
that the source activity was rapidly increasing. This eventually led to the
Giant Flare of December 27th 2004, for which a possible soft gamma-ray (>80
keV) early afterglow has been detected.
The deep observations allowed us to discover the persistent emission in hard
X-rays (20-150 keV) from 1806-20 and 1900+14, the latter being in a quiescent
state, and to directly compare the spectral characteristics of all Magnetars
(two SGRs and three Anomalous X-ray Pulsars) detected with INTEGRAL.Comment: 8 pages, 7 figures, Presented at the conference "Isolated Neutron
Stars: from the Surface to the Interior", London, UK, 24-28 April 200
The first multi-wavelength campaign of AXP 4U 0142+61 from radio to hard X-rays
For the first time a quasi-simultaneous multi-wavelength campaign has been
performed on an Anomalous X-ray Pulsar from the radio to the hard X-ray band.
4U 0142+61 was an INTEGRAL target for 1 Ms in July 2005. During these
observations it was also observed in the X-ray band with Swift and RXTE, in the
optical and NIR with Gemini North and in the radio with the WSRT. In this paper
we present the source-energy distribution. The spectral results obtained in the
individual wave bands do not connect smoothly; apparently components of
different origin contribute to the total spectrum. Remarkable is that the
INTEGRAL hard X-ray spectrum (power-law index 0.79 +/- 0.10) is now measured up
to an energy of ~230 keV with no indication of a spectral break. Extrapolation
of the INTEGRAL power-law spectrum to lower energies passes orders of magnitude
underneath the NIR and optical fluxes, as well as the low ~30 microJy (2 sigma)
upper limit in the radio band.Comment: 6 pages, 1 figure. To be published in the proceedings of the
conference "Isolated Neutron Stars: from the Interior to the Surface" (April
24-28, 2006, London, UK), eds. S. Zane, R. Turolla and D. Pag
A multistate model of health transitions in older people: a secondary analysis of ASPREE clinical trial data
Background: Understanding the nature of transitions from a healthy state to chronic diseases and death is important for planning health-care system requirements and interventions. We aimed to quantify the trajectories of disease and disability in a population of healthy older people. Methods: We conducted a secondary analysis of data from the ASPREE trial, which was done in 50 sites in Australia and the USA and recruited community-dwelling, healthy individuals who were aged 70 years or older (≥65 years for Black and Hispanic people in the USA) between March 10, 2010, and Dec 24, 2014. Participants were followed up with annual face-to-face visits, biennial assessments of cognitive function, and biannual visits for physical function until death or June 12, 2017, whichever occurred first. We used multistate models to examine transitions from a healthy state to first intermediate disease events (ie, cancer events, stroke events, cardiac events, and physical disability or dementia) and, ultimately, to death. We also examined the effects of age and sex on transition rates using Cox proportional hazards regression models. Findings: 19 114 participants with a median age of 74·0 years (IQR 71·6–77·7) were included in our analyses. During a median follow-up of 4·7 years (IQR 3·6–5·7), 1933 (10·1%) of 19 114 participants had an incident cancer event, 487 (2·5%) had an incident cardiac event, 398 (2·1%) had an incident stroke event, 924 (4·8%) developed persistent physical disability or dementia, and 1052 (5·5%) died. 15 398 (80·6%) individuals did not have any of these events during follow-up. The highest proportion of deaths followed incident cancer (501 [47·6%] of 1052) and 129 (12·3%) participants transitioned from disability or dementia to death. Among 12 postulated transitions, transitions from the intermediate states to death had much higher rates than transitions from a healthy state to death. The progression rates to death were 158 events per 1000 person-years (95% CI 144–172) from cancer, 112 events per 1000 person-years (86–145) from stroke, 88 events per 1000 person-years (68–111) from cardiac disease, 69 events per 1000 person-years (58–82) from disability or dementia, and four events per 1000 person-years (4–5) from a healthy state. Age was significantly associated with an accelerated rate for most transitions. Male sex (vs female sex) was significantly associated with an accelerate rate for five of 12 transitions. Interpretation: We describe a multistate model in a healthy older population in whom the most common transition was from a healthy state to cancer. Our findings provide unique insights into the frequency of events, their transition rates, and the impact of age and sex. These results have implications for preventive health interventions and planning for appropriate levels of residential care in healthy ageing populations. Funding: The National Institutes of Health
Extreme Ultra-Violet Spectroscopy of the Lower Solar Atmosphere During Solar Flares
The extreme ultraviolet portion of the solar spectrum contains a wealth of
diagnostic tools for probing the lower solar atmosphere in response to an
injection of energy, particularly during the impulsive phase of solar flares.
These include temperature and density sensitive line ratios, Doppler shifted
emission lines and nonthermal broadening, abundance measurements, differential
emission measure profiles, and continuum temperatures and energetics, among
others. In this paper I shall review some of the advances made in recent years
using these techniques, focusing primarily on studies that have utilized data
from Hinode/EIS and SDO/EVE, while also providing some historical background
and a summary of future spectroscopic instrumentation.Comment: 34 pages, 8 figures. Submitted to Solar Physics as part of the
Topical Issue on Solar and Stellar Flare
CARME — The CRYRING Array for Reaction MEasurements: A new approach to study nuclear reactions using storage rings
Associations of body size with all-cause and cause-specific mortality in healthy older adults
In the general population, body mass index (BMI) and waist circumference are recognized risk factors for several chronic diseases and all-cause mortality. However, whether these associations are the same for older adults is less clear. The association of baseline BMI and waist circumference with all-cause and cause-specific mortality was investigated in 18,209 Australian and US participants (mean age: 75.1 ± 4.5 years) from the ASPirin in Reducing Events in the Elderly (ASPREE) study, followed up for a median of 6.9 years (IQR: 5.7, 8.0). There were substantially different relationships observed in men and women. In men, the lowest risk of all-cause and cardiovascular mortality was observed with a BMI in the range 25.0–29.9 kg/m2 [HR25-29.9 vs 21–24.9 kg/m2: 0.85; 95% CI, 0.73–1.00] while the highest risk was in those who were underweight [HRBMI <21 kg/m2 vs BMI 21–24.9 kg/m2: 1.82; 95% CI 1.30–2.55], leading to a clear U-shaped relationship. In women, all-cause mortality was highest in those with the lowest BMI leading to a J-shaped relationship (HRBMI <21 kg/m2 vs BMI 21–24.9 kg/m2: 1.64; 95% CI 1.26–2.14). Waist circumference showed a weaker relationship with all-cause mortality in both men and women. There was little evidence of a relationship between either index of body size and subsequent cancer mortality in men or women, while non-cardiovascular non-cancer mortality was higher in underweight participants. For older men, being overweight was found to be associated with a lower risk of all-cause mortality, while among both men and women, a BMI in the underweight category was associated with a higher risk. Waist circumference alone had little association with all-cause or cause-specific mortality risk. Trial registration ASPREE https://ClinicalTrials.gov number NCT01038583.Prudence R. Carr, Katherine L. Webb, Johannes T. Neumann, Le T. P. Thao, Lawrence J. Beilin, Michael E. Ernst, Bernadette Fitzgibbon, Danijela Gasevic, Mark R. Nelson, Anne B. Newman, Suzanne G. Orchard, Alice Owen, Christopher M. Reid, Nigel P. Stocks, Andrew M. Tonkin, Robyn L. Woods, John J. McNei
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