The application of dendrometers to alpine dwarf shrubs – a case study to investigate stem growth responses to environmental conditions

Considering the recent widespread greening and browning trends associated with shrubs in arctic–alpine ecosystems, further understanding of how these shrubs respond in a rapidly changing environment is of crucial importance. We here monitor shrub growth, using high-precision dendrometers to produce fine-scale intra-annual growth patterns from hourly stem diameter variability in a widespread evergreen species (Empetrum nigrum ssp. hermaphroditum). Measurements were taken at a micrometer scale for the period 2015 till 2018 on exposed and mostly snow-free ridge positions. With the same temporal resolution, we collected near-ground environmental data and identified on-site controls of growth behavior. We found high inter-plant variability in radial stem growth but strong similarities in response patterns to the local environment. Our results suggest that the evergreen species is highly adapted to the specific local conditions, remaining partly photosynthetically active during the snow-free winter, which facilitates carbohydrate accumulation for early-season physiological activities. Additionally, we discovered a phase of radial stem shrinkage during the winter months, which can be attributed to an active cell water reduction to protect the plant from frost damage. We conclude that soil moisture availability and winter snow conditions are the main drivers of radial stem growth of E. hermaphroditum in arctic and alpine regions and could negatively affect the species' distribution in a warming climate

Wild Mountain reindeer Rangifer tarandus tarandus winter foraging: snow-free areas a key resource for feeding

In a landscape with patchily distributed forage resources, an animal’s distribution may reflect the distribution of the resources if the population is forage-limited in time or space. This may be particularly explicit in climatically extreme and seasonally variable environments, notably alpine and polar environments during winter. Sustainable management considers the amount of available alpine ground lichen in winter as a predictor of carrying capacity for the last remaining populations of wild European Mountain reindeer Rangifer tarandus tarandus in alpine environments in South Norway. Ground lichen growth is constrained to elevated, wind-blown, snow-free ridges. However, wild Mountain reindeer also persist in areas providing little lichen resources. Our alternative functional hypothesis is that the critical resource is the amount of snow-free feeding areas during winter, which provide direct access to forage, likely to be energy-profitable regardless of the type of vegetation. We sampled animal-borne videos from wild Mountain reindeer during maximum accumulation of snow in late winter/spring, in three contrasting areas providing variable amounts of ground lichen and alternative vegetation resources. Direct observations of reindeer foraging via videos document an active selection and strong preference for feeding on snow-free patches, regardless of type of vegetation. Active ‘cratering’ in snow was not observed. In contrast, walking behaviours occurred much more frequently across snow-covered areas. Remote sensing data and analyses corroborated these observations. In the sustainable management of wild Mountain reindeer amounts of vegetated snow-free areas is an important functional predictor of winter carrying capacity. Alpine · Winter · Wild reindeer · Video · Snow-free areaspublishedVersio

Charge transfer and heat in photocatalysis

Photocatalysis occurs very often in the life of ordinary people. Its simplest example is the photosynthesis of plants and algae. It is difficult to overestimate how important this photochemical reaction is because the possibilities of its application are ranging from water purification to the development of a cheap bombed energy source. This work is aimed at a more detailed investigation of the photocatalytic reaction. For this purpose, the present work presents the analysis of the latest and most important research in the field of plasmon-induced photocatalysis. As a model system, the authors mainly used molecules of the thiol group such as nitrobenzenethiol or nitrophenol adsorbed on plasmonic nanoparticles. To characterize the resulting systems, Raman spectroscopy (SERS) was used. It is reported that the main mechanism for triggering photocatalytic reactions is the transition of hot charge carriers under the influence of light, which leads to a local surface plasmon resonance (LSPR) and a change in temperature by internal or external heating of the system. It should be noted that the main factor influencing the photocatalytic activity was not fully determined due to the numerous diverse opinions on the issue

Associations between exemption and survival outcomes in the UK's primary care pay-for-performance programme:a retrospective cohort study

PublishedJournal ArticleThis is the final version of the article. Available from BMJ Publishing Group via the DOI in this record.OBJECTIVES: The UK's Quality and Outcomes Framework permits practices to exempt patients from financially-incentivised performance targets. To better understand the determinants and consequences of being exempted from the framework, we investigated the associations between exception reporting, patient characteristics and mortality. We also quantified the proportion of exempted patients that met quality targets for a tracer condition (diabetes). DESIGN: Retrospective longitudinal study, using individual patient data from the Clinical Practice Research Datalink. SETTING: 644 general practices, 2006/7 to 2011/12. PARTICIPANTS: Patients registered with study practices for at least one year over the study period, with at least one condition of interest (2 460 341 in total). MAIN OUTCOME MEASURES: Exception reporting rates by reason (clinical contraindication, patient dissent); all-cause mortality in year following exemption. Analyses with logistic and Cox proportional-hazards regressions, respectively. RESULTS: The odds of being exempted increased with age, deprivation and multimorbidity. Men were more likely to be exempted but this was largely attributable to higher prevalence of conditions with high exemption rates. Modest associations remained, with women more likely to be exempted due to clinical contraindication (OR 0.90, 99% CI 0.88 to 0.92) and men more likely to be exempted due to informed dissent (OR 1.08, 99% CI 1.06 to 1.10). More deprived areas (both for practice location and patient residence) were non-linearly associated with higher exception rates, after controlling for comorbidities and other covariates, with stronger associations for clinical contraindication. Compared with patients with a single condition, odds ratios for patients with two, three, or four or more conditions were respectively 4.28 (99% CI 4.18 to 4.38), 16.32 (99% CI 15.82 to 16.83) and 68.69 (99% CI 66.12 to 71.37) for contraindication, and 2.68 (99% CI 2.63 to 2.74), 4.02 (99% CI 3.91 to 4.13) and 5.17 (99% CI 5.00 to 5.35) for informed dissent. Exempted patients had a higher adjusted risk of death in the following year than non-exempted patients, regardless of whether this exemption was for contraindication (hazard ratio 1.37, 99% CI 1.33 to 1.40) or for informed dissent (1.20, 99% CI 1.17 to 1.24). On average, quality standards were met for 48% of exempted patients in the diabetes domain, but there was wide variation across indicators (ranging from 8 to 80%). CONCLUSIONS: Older, multimorbid and more deprived patients are more likely to be exempted from the scheme. Exception reported patients are more likely to die in the following year, whether they are exempted by the practice for a contraindication or by themselves through informed dissent. Further research is needed to understand the relationship between exception reporting and patient outcomes.NIHR School for Primary Care Research (Project #141); Medical Research Council; Health eResearch Centre grant MR/K006665/1

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

X-ray emission from the Sombrero galaxy: discrete sources

We present a study of discrete X-ray sources in and around the bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival Chandra observations with a total exposure of ~200 ks. With a detection limit of L_X = 1E37 erg/s and a field of view covering a galactocentric radius of ~30 kpc (11.5 arcminute), 383 sources are detected. Cross-correlation with Spitler et al.'s catalogue of Sombrero globular clusters (GCs) identified from HST/ACS observations reveals 41 X-rays sources in GCs, presumably low-mass X-ray binaries (LMXBs). We quantify the differential luminosity functions (LFs) for both the detected GC and field LMXBs, whose power-low indices (~1.1 for the GC-LF and ~1.6 for field-LF) are consistent with previous studies for elliptical galaxies. With precise sky positions of the GCs without a detected X-ray source, we further quantify, through a fluctuation analysis, the GC LF at fainter luminosities down to 1E35 erg/s. The derived index rules out a faint-end slope flatter than 1.1 at a 2 sigma significance, contrary to recent findings in several elliptical galaxies and the bulge of M31. On the other hand, the 2-6 keV unresolved emission places a tight constraint on the field LF, implying a flattened index of ~1.0 below 1E37 erg/s. We also detect 101 sources in the halo of Sombrero. The presence of these sources cannot be interpreted as galactic LMXBs whose spatial distribution empirically follows the starlight. Their number is also higher than the expected number of cosmic AGNs (52+/-11 [1 sigma]) whose surface density is constrained by deep X-ray surveys. We suggest that either the cosmic X-ray background is unusually high in the direction of Sombrero, or a distinct population of X-ray sources is present in the halo of Sombrero.Comment: 11 figures, 5 tables, ApJ in pres

Azimuthal anisotropy of charged particles at high transverse momenta in PbPb collisions at sqrt(s[NN]) = 2.76 TeV

The azimuthal anisotropy of charged particles in PbPb collisions at nucleon-nucleon center-of-mass energy of 2.76 TeV is measured with the CMS detector at the LHC over an extended transverse momentum (pt) range up to approximately 60 GeV. The data cover both the low-pt region associated with hydrodynamic flow phenomena and the high-pt region where the anisotropies may reflect the path-length dependence of parton energy loss in the created medium. The anisotropy parameter (v2) of the particles is extracted by correlating charged tracks with respect to the event-plane reconstructed by using the energy deposited in forward-angle calorimeters. For the six bins of collision centrality studied, spanning the range of 0-60% most-central events, the observed v2 values are found to first increase with pt, reaching a maximum around pt = 3 GeV, and then to gradually decrease to almost zero, with the decline persisting up to at least pt = 40 GeV over the full centrality range measured.Comment: Replaced with published version. Added journal reference and DO

Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

Combined search for the quarks of a sequential fourth generation

Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.Comment: Replaced with published version. Added journal reference and DO