Structural parameters for globular clusters in NGC 5128. III. ACS surface-brightness profiles and model fits

We present internal surface-brightness profiles, based on HST/ACS imaging in the F606W bandpass, for 131 globular cluster (GC) candidates with luminosities 10^4 - 3 x 10^6 solar, in the giant elliptical galaxy NGC 5128. Several structural models are fit to the profile of each cluster and combined with mass-to-light ratios from population-synthesis models, to derive a catalogue of fundamental structural and dynamical parameters parallel in form to the catalogues recently produced by McLaughlin & van der Marel and Barmby et al. for GCs and massive young star clusters in Local Group galaxies. As part of this, we provide corrected and extended parameter estimates for another 18 clusters in NGC 5128, which we observed previously. We show that, like GCs in the Milky Way and some of its satellites, the majority of globulars in NGC 5128 are well fit by isotropic Wilson models, which have intrinsically more distended envelope structures than the standard King lowered isothermal spheres. We use our models to predict internal velocity dispersions for every cluster in our sample. These predictions agree well in general with the observed dispersions in a small number of clusters for which spectroscopic data are available. In a subsequent paper, we use these results to investigate scaling relations for GCs in NGC 5128.Comment: MNRAS, in press. 28 pages. Full data tables available at http://www.astro.keele.ac.uk/~dem/clusters.htm

N-body models of globular clusters: metallicity, half-light radii and mass-to-light ratios

Size differences of approx. 20% between red (metal-rich) and blue (metal-poor) sub-populations of globular clusters have been observed, generating an ongoing debate as to weather these originate from projection effects or the difference in metallicity. We present direct N-body simulations of metal-rich and metal-poor stellar populations evolved to study the effects of metallicity on cluster evolution. The models start with N = 100000 stars and include primordial binaries. We also take metallicity dependent stellar evolution and an external tidal field into account. We find no significant difference for the half-mass radii of those models, indicating that the clusters are structurally similar. However, utilizing observational tools to fit half-light (or effective) radii confirms that metallicity effects related to stellar evolution combined with dynamical effects such as mass segregation produce an apparent size difference of 17% on average. The metallicity effect on the overall cluster luminosity also leads to higher mass-to-light ratios for metal-rich clusters.Comment: 14 pages, 10 figures, accepted for publication in MNRA

Risk factors for cardiovascular disease in people with idiopathic pulmonary fibrosis: a population-based study

OBJECTIVE: People with idiopathic pulmonary fibrosis (IPF) have been shown to be at an increased risk for cardiovascular (CV) disease, but reasons for this are unknown. The aim of this study was to compare the prevalence of common CV risk factors in people with IPF and the general population and establish the incidence of ischemic heart disease (IHD) and stroke after the diagnosis of IPF, controlling for these risk factors. METHODS: We used data from a large, UK primary care database to identify incident cases of IPF and matched general-population control subjects. We compared the prevalence of risk factors for CV disease and prescription of CV medications in people with IPF (before diagnosis) with control subjects from the general population and assessed the incidence of IHD and stroke in people with IPF (after diagnosis) compared with control subjects. RESULTS: We identified 3,211 cases of IPF and 12,307 control subjects. Patients with IPF were more likely to have a record of hypertension (OR, 1.31; 95% CI, 1.19-1.44), and diabetes (OR, 1.20; 95% CI, 1.07-1.34) compared with control subjects; they were also more likely to have been prescribed several CV drugs. The rate of first-time IHD events was more than twice as high in patients than control subjects (rate ratio, 2.32; 95% CI, 1.85-2.93; P < .001), but the incidence of stroke was only marginally higher (P = .09). Rate ratios for IHD and stroke were not altered substantially after adjusting for CV risk factors. CONCLUSIONS: Several CV risk factors were more prevalent in people with IPF; however, this did not account for the increased rate of IHD in this group of patients

Association of Accelerometry-Measured Physical Activity and Cardiovascular Events in Mobility-Limited Older Adults: The LIFE (Lifestyle Interventions and Independence for Elders) Study.

BACKGROUND:Data are sparse regarding the value of physical activity (PA) surveillance among older adults-particularly among those with mobility limitations. The objective of this study was to examine longitudinal associations between objectively measured daily PA and the incidence of cardiovascular events among older adults in the LIFE (Lifestyle Interventions and Independence for Elders) study. METHODS AND RESULTS:Cardiovascular events were adjudicated based on medical records review, and cardiovascular risk factors were controlled for in the analysis. Home-based activity data were collected by hip-worn accelerometers at baseline and at 6, 12, and 24 months postrandomization to either a physical activity or health education intervention. LIFE study participants (n=1590; age 78.9±5.2 [SD] years; 67.2% women) at baseline had an 11% lower incidence of experiencing a subsequent cardiovascular event per 500 steps taken per day based on activity data (hazard ratio, 0.89; 95% confidence interval, 0.84-0.96; P=0.001). At baseline, every 30 minutes spent performing activities ≥500 counts per minute (hazard ratio, 0.75; confidence interval, 0.65-0.89 [P=0.001]) were also associated with a lower incidence of cardiovascular events. Throughout follow-up (6, 12, and 24 months), both the number of steps per day (per 500 steps; hazard ratio, 0.90, confidence interval, 0.85-0.96 [P=0.001]) and duration of activity ≥500 counts per minute (per 30 minutes; hazard ratio, 0.76; confidence interval, 0.63-0.90 [P=0.002]) were significantly associated with lower cardiovascular event rates. CONCLUSIONS:Objective measurements of physical activity via accelerometry were associated with cardiovascular events among older adults with limited mobility (summary score >10 on the Short Physical Performance Battery) both using baseline and longitudinal data. CLINICAL TRIAL REGISTRATION:URL: http://www.clinicaltrials.gov. Unique identifier: NCT01072500

Continuous isoprene measurements in a UK temperate forest for a whole growing season: effects of drought stress during the 2018 heatwave

Isoprene concentrations were measured at four heights below, within and above the forest canopy in Wytham Woods (UK) throughout the summer of 2018 using custom-built gas chromatographs (the iDirac). These observations were complemented with selected ancillary variables, including air temperature, photosynthetically active radiation (PAR), occasional leaf gas exchange measurements and satellite retrievals of normalized difference vegetation and water indices (NDVI and NDWI). The campaign overlapped with a long and uninterrupted heatwave accompanied by moderate drought. Peak isoprene concentrations during the heatwave-drought were up to a factor of 4 higher than those before or after. Higher temperatures during the heatwave could not account for all the observed isoprene; the enhanced abundances correlated with drought stress. Leaf-level emissions confirmed this and also included compounds associated with ecosystem stress. This work highlights that a more in-depth understanding of the effects of drought stress is required to better characterize isoprene emissions

Status of Muon Collider Research and Development and Future Plans

The status of the research on muon colliders is discussed and plans are outlined for future theoretical and experimental studies. Besides continued work on the parameters of a 3-4 and 0.5 TeV center-of-mass (CoM) energy collider, many studies are now concentrating on a machine near 0.1 TeV (CoM) that could be a factory for the s-channel production of Higgs particles. We discuss the research on the various components in such muon colliders, starting from the proton accelerator needed to generate pions from a heavy-Z target and proceeding through the phase rotation and decay ($\pi \to \mu \nu_{\mu}$) channel, muon cooling, acceleration, storage in a collider ring and the collider detector. We also present theoretical and experimental R & D plans for the next several years that should lead to a better understanding of the design and feasibility issues for all of the components. This report is an update of the progress on the R & D since the Feasibility Study of Muon Colliders presented at the Snowmass'96 Workshop [R. B. Palmer, A. Sessler and A. Tollestrup, Proceedings of the 1996 DPF/DPB Summer Study on High-Energy Physics (Stanford Linear Accelerator Center, Menlo Park, CA, 1997)].Comment: 95 pages, 75 figures. Submitted to Physical Review Special Topics, Accelerators and Beam

Quantum error mitigation in quantum annealing

Quantum Error Mitigation (QEM) presents a promising near-term approach to reduce error when estimating expectation values in quantum computing. Here, we introduce QEM techniques tailored for quantum annealing, using Zero-Noise Extrapolation (ZNE). We implement ZNE through zero-temperature extrapolation as well as energy-time rescaling. We conduct experimental investigations into the quantum critical dynamics of a transverse-field Ising spin chain, demonstrating the successful mitigation of thermal noise through both of these techniques. Moreover, we show that energy-time rescaling effectively mitigates control errors in the coherent regime where the effect of thermal noise is minimal. Our ZNE results agree with exact calculations of the coherent evolution over a range of annealing times that exceeds the coherent annealing range by almost an order of magnitude.Comment: 10 pages, 5 figure

Inducible deletion of CD28 prior to secondary nippostrongylus brasiliensis infection impairs worm expulsion and recall of protective memory CD4 (+) T cell responses

IL-13 driven Th2 immunity is indispensable for host protection against infection with the gastrointestinal nematode Nippostronglus brasiliensis. Disruption of CD28 mediated costimulation impairs development of adequate Th2 immunity, showing an importance for CD28 during the initiation of an immune response against this pathogen. In this study, we used global CD28−/− mice and a recently established mouse model that allows for inducible deletion of the cd28 gene by oral administration of tamoxifen (CD28−/loxCre+/−+TM) to resolve the controversy surrounding the requirement of CD28 costimulation for recall of protective memory responses against pathogenic infections. Following primary infection with N. brasiliensis, CD28−/− mice had delayed expulsion of adult worms in the small intestine compared to wild-type C57BL/6 mice that cleared the infection by day 9 post-infection. Delayed expulsion was associated with reduced production of IL-13 and reduced serum levels of antigen specific IgG1 and total IgE. Interestingly, abrogation of CD28 costimulation in CD28−/loxCre+/− mice by oral administration of tamoxifen prior to secondary infection with N. brasiliensis resulted in impaired worm expulsion, similarly to infected CD28−/− mice. This was associated with reduced production of the Th2 cytokines IL-13 and IL-4, diminished serum titres of antigen specific IgG1 and total IgE and a reduced CXCR5+ TFH cell population. Furthermore, total number of CD4+ T cells and B220+ B cells secreting Th1 and Th2 cytokines were significantly reduced in CD28−/− mice and tamoxifen treated CD28−/loxCre+/− mice compared to C57BL/6 mice. Importantly, interfering with CD28 costimulatory signalling before re-infection impaired the recruitment and/or expansion of central and effector memory CD4+ T cells and follicular B cells to the draining lymph node of tamoxifen treated CD28−/loxCre+/− mice. Therefore, it can be concluded that CD28 costimulation is essential for conferring host protection during secondary N. brasiliensis infection

Multidecadal variability in Atlas cedar growth in northwest Africa during the last 850 years: implications for dieback and conservation of an endangered species

Widespread forest dieback is a phenomenon of global concern that requires an improved understanding of the relationship between tree growth and climate to support conservation efforts. One priority for conservation is the Atlas cedar (Cedrus atlantica), an endangered species exhibiting dieback throughout its North African range. In this study, we evaluate the long-term context for recent dieback and develop a projection of future C. atlantica growth by exploring the periodic variability of its growth through time. First, we present a new C. atlantica tree- ring chronology (1150–2013 CE) from the Middle Atlas mountains, Morocco. We then compare the new chronology to existing C. atlantica chronologies in Morocco and use principal components analysis (PCA) to isolate the common periodic signal from the seven longest available records (PCA7, 1271–1984 CE) in the Middle and High Atlas portions of the C. atlantica range. PCA7 captures 55.7% of the variance and contains significant multidecadal ( ̃95yr, ̃57yr, ̃21yr) periodic components, revealed through spectral and wavelet analyses. Parallel analyses of historical climate data (1901–2016 CE) suggests that the multidecadal growth signal ori- ginates primarily in growing season (spring and summer) precipitation variability, compounded by slow- changing components of summer and winter temperatures. Finally, we model the long-term growth patterns between 1271–1984 CE using a small number (three to four) of harmonic components, illustrating that sup- pressed growth since the 1970s – a factor implicated in the dieback of this species – is consistent with recurrent climatically-driven growth declines. Forward projection of this model suggests two climatically-favourable periods for growth in the 21st century that may enhance current conservation actions for the long-term survival of the C. atlantica in the Middle and High Atlas mountains