Planck 2015 results Ade, P A R; Aghanim, N; Arnaud, M ...
Astronomy and astrophysics (Berlin),
10/2016, Letnik:
594
Journal Article
Recenzirano
Odprti dostop
We present the implications for cosmic inflation of the Planck measurements of the cosmic microwave background (CMB) anisotropies in both temperature and polarization based on the full Planck survey, ...which includes more than twice the integration time of the nominal survey used for the 2013 release papers. The Planck full mission temperature data and a first release of polarization data on large angular scales measure the spectral index of curvature perturbations to be n sub(s)= 0.968 + or - 0.006 and tightly constrain its scale dependence to dn sub(s)/ dlnk= -0.003 + or - 0.007 when combined with the Planck lensing likelihood. When the Planck high-scriptl polarization data are included, the results are consistent and uncertainties are further reduced. The upper bound on the tensor-to-scalar ratio is r sub(0.002)< 0.11 (95% CL). This upper limit is consistent with the B-mode polarization constraint r< 0.12 (95% CL) obtained from a joint analysis of the BICEP2/Keck Array and Planck data. These results imply that V(phi) proportional = to phi super(2) and natural inflation are now disfavoured compared to models predicting a smaller tensor-to-scalar ratio, such as R super(2) inflation. We search for several physically motivated deviations from a simple power-law spectrum of curvature perturbations, including those motivated by a reconstruction of the inflaton potential not relying on the slow-roll approximation. We find that such models are not preferred, either according to a Bayesian model comparison or according to a frequentist simulation-based analysis. Three independent methods reconstructing the primordial power spectrum consistently recover a featureless and smooth scriptP sub()R super(()k)over the range of scales 0.008 Mpc super(-1)< or = k< or = 0.1 Mpc super(-1). At large scales, each method finds deviations from a power law, connected to a deficit at multipoles scriptlapproximate 20-40 in the temperature power spectrum, but at an uncompelling statistical significance owing to the large cosmic variance present at these multipoles. By combining power spectrum and non-Gaussianity bounds, we constrain models with generalized Lagrangians, including Galileon models and axion monodromy models. The Planck data are consistent with adiabatic primordial perturbations, and the estimated values for the parameters of the base Lambda cold dark matter (LambdaCDM) model are not significantly altered when more general initial conditions are admitted. In correlated mixed adiabatic and isocurvature models, the 95% CL upper bound for the non-adiabatic contribution to the observed CMB temperature variance is alpha sub(non - adi) < 1.9%, 4.0%, and 2.9% for CDM, neutrino density, and neutrino velocity isocurvature modes, respectively. We have tested inflationary models producing an anisotropic modulation of the primordial curvature power spectrum findingthat the dipolar modulation in the CMB temperature field induced by a CDM isocurvature perturbation is not preferred at a statistically significant level. We also establish tight constraints on a possible quadrupolar modulation of the curvature perturbation. These results are consistent with the Planck 2013 analysis based on the nominal mission data and further constrain slow-roll single-field inflationary models, as expected from the increased precision of Planck data using the full set of observations.
The critically endangered African forest elephant (Loxodonta cyclotis) plays a vital role in maintaining the structure and composition of Afrotropical forests, but basic information is lacking ...regarding the drivers of elephant movement and behavior at landscape scales. We use GPS location data from 96 individuals throughout Gabon to determine how five movement behaviors vary at different scales, how they are influenced by anthropogenic and environmental covariates, and to assess evidence for behavioral syndromes-elephants which share suites of similar movement traits. Elephants show some evidence of behavioral syndromes along an 'idler' to 'explorer' axis-individuals that move more have larger home ranges and engage in more 'exploratory' movements. However, within these groups, forest elephants express remarkable inter-individual variation in movement behaviours. This variation highlights that no two elephants are the same and creates challenges for practitioners aiming to design conservation initiatives.
Planck 2015 results Ade, P A R; Aghanim, N; Arnaud, M ...
Astronomy and astrophysics (Berlin),
10/2016, Letnik:
594
Journal Article
Recenzirano
Odprti dostop
This paper presents cosmological results based on full-mission Planck observations of temperature and polarization anisotropies of the cosmic microwave background (CMB) radiation. Our results are in ...very good agreement with the 2013 analysis of the Planck nominal-mission temperature data, but with increased precision. The temperature and polarization power spectra are consistent with the standard spatially-flat 6-parameter LambdaCDM cosmology with a power-law spectrum of adiabatic scalar perturbations (denoted "base LambdaCDM" in this paper). From the Planck temperature data combined with Planck lensing, for this cosmology we find a Hubble constant, H sub(0)= (67.8 + or - 0.9) km s super(-1) Mpc super(-1), a matter density parameter Omega sub(m)= 0.308 + or - 0.012, and a tilted scalar spectral index with n sub(s)= 0.968 + or - 0.006, consistent with the 2013 analysis. Note that in this abstract we quote 68% confidence limits on measured parameters and 95% upper limits on other parameters. We present the first results of polarization measurements with the Low Frequency Instrument at large angular scales. Combined with the Planck temperature and lensing data, these measurements give a reionization optical depth of T= 0.066 + or - 0.016, corresponding to a reionization redshift of (ProQuest: Formulae and/or non-USASCII text omitted). These results are consistent with those from WMAP polarization measurements cleaned for dust emission using 353-GHz polarization maps from the High Frequency Instrument. We find no evidence for any departure from base LambdaCDM in the neutrino sector of the theory; for example, combining Planck observations with other astrophysical data we find N sub(eff)= 3.15 + or - 0.23 for the effective number of relativistic degrees of freedom, consistent with the value N sub(eff)= 3.046 of the Standard Model of particle physics. The sum of neutrino masses is constrained to Sigma m sub(nu)< 0.23 eV. The spatial curvature of our Universe is found to be very close to zero, with Omega sub()K< 0.005. Adding a tensor component as a single-parameter extension to base LambdaCDM we find an upper limit on the tensor-to-scalar ratio of r sub(0.002)< 0.11, consistent with the Planck 2013 results and consistent with the B-mode polarization constraints from a joint analysis of BICEP2, Keck Array, and Planck(BKP) data. Adding the BKP B-mode data to our analysis leads to a tighter constraint of r 0.002 < 0.09 and disfavours inflationarymodels with a V(phi) proportional = to phi super(2) potential. The addition of Planck polarization data leads to strong constraints on deviations from a purely adiabatic spectrum of fluctuations. We find no evidence for any contribution from isocurvature perturbations or from cosmic defects. Combining Planck data with other astrophysical data, including Type Ia supernovae, the equation of state of dark energy is constrained to w= -1.006 + or - 0.045, consistent with the expected value for a cosmological constant. The standard big bang nucleosynthesis predictions for the helium and deuterium abundances for the best-fit Planck base LambdaCDM cosmology are in excellent agreement with observations. We also constraints on annihilating dark matter and on possible deviations from the standard recombination history. In neither case do we find no evidence for new physics. The Planck results for base LambdaCDM are in good agreement with baryon acoustic oscillation data and with the JLA sample of Type Ia supernovae. However, as in the 2013 analysis, the amplitude of the fluctuation spectrum is found to be higher than inferred from some analyses of rich cluster counts and weak gravitational lensing. We show that these tensions cannot easily be resolved with simple modifications of the base LambdaCDM cosmology. Apart from these tensions, the base LambdaCDM cosmology provides an excellent description of the Planck CMB observations and many other astrophysical data sets.
This paper presents a novel technique for mitigating electrode backgrounds that limit the sensitivity of searches for low-mass dark matter (DM) using xenon time projection chambers. In the Large ...Underground Xenon (LUX) detector, signatures of low-mass DM interactions would be very low-energy (~ keV) scatters in the active target that ionize only a few xenon atoms and seldom produce detectable scintillation signals. In this regime, extra precaution is required to reject a complex set of low-energy electron backgrounds that have long been observed in this class of detector. Noticing backgrounds from the wire grid electrodes near the top and bottom of the active target are particularly pernicious, we develop a machine learning technique based on ionization pulse shape to identify and reject these events. We demonstrate the technique can improve Poisson limits on low-mass DM interactions by a factor of 1.7–3 with improvement depending heavily on the size of ionization signals. We use the technique on events in an effective 5 tonne·day exposure from LUX's 2013 science operation to place strong limits on low-mass DM particles with masses in the range mχ ∈ 0.15 – 10 GeV . This machine learning technique is expected to be useful for near-future experiments, such as LUX-ZEPLIN and XENONnT, which hope to perform low-mass DM searches with the stringent background control necessary to make a discovery.
ABSTRACT
While seasonal outlooks have been operational for many years, until recently the extended‐range timescale referred to as subseasonal‐to‐seasonal (S2S) has received little attention. S2S ...prediction fills the gap between short‐range weather prediction and long‐range seasonal outlooks. Decisions in a range of sectors are made in this extended‐range lead time; therefore, there is a strong demand for this new generation of forecasts. International efforts are under way to identify key sources of predictability, improve forecast skill and operationalize aspects of S2S forecasts; however, challenges remain in advancing this new frontier. If S2S predictions are to be used effectively, it is important that, along with science advances, an effort is made to develop, communicate and apply these forecasts appropriately. In this study, the emerging operational S2S forecasts are presented to the wider weather and climate applications community by undertaking the first comprehensive review of sectoral applications of S2S predictions, including public health, disaster preparedness, water management, energy and agriculture. The value of applications‐relevant S2S predictions is explored, and the opportunities and challenges facing their uptake are highlighted. It is shown how social sciences can be integrated with S2S development, from communication to decision‐making and valuation of forecasts, to enhance the benefits of ‘climate services’ approaches for extended‐range forecasting. While S2S forecasting is at a relatively early stage of development, it is concluded that it presents a significant new window of opportunity that can be explored for application‐ready capabilities that could allow many sectors the opportunity to systematically plan on a new time horizon.
A search for mixing between active neutrinos and light sterile neutrinos has been performed by looking for muon neutrino disappearance in two detectors at baselines of 1.04 and 735 km, using a ...combined MINOS and MINOS+ exposure of 16.36×10^{20} protons on target. A simultaneous fit to the charged-current muon neutrino and neutral-current neutrino energy spectra in the two detectors yields no evidence for sterile neutrino mixing using a 3+1 model. The most stringent limit to date is set on the mixing parameter sin^{2}θ_{24} for most values of the sterile neutrino mass splitting Δm_{41}^{2}>10^{-4} eV^{2}.
Platinum nanoparticles (NPs) have been successfully assembled on noncovalently poly(diallyldimethylammonium chloride)-functionalized multiwalled carbon nanotubes (MWCNTs) via microwave-assisted ...polyol reduction and seed-mediated growth methods. Pt NPs were uniformly deposited on MWCNT support with Pt loading of 10−93 wt %. The results show that the increase in the Pt NP loading on MWCNTs leads to a positive shift of the peak potential for the reduction of Pt−OHad, a negative shift of the peak potential for oxidation of adsorbed CO, an increase in the peak current for the methanol oxidation reaction, and a positive shift for the half-wave potential of the oxygen reduction reaction in acid solutions, even though the size of the Pt NPs also increased with the Pt loading. The increase of the electrocatalytic activity of Pt/MWCNTs shows a characteristic S-shaped profile as a function of the Pt NP loading. To explain the S-shaped dependence of the activity of Pt/MWCNTs on Pt loading, a new concept of interconnectivity of Pt NPs was introduced. Interconnectivity is defined as the ratio of the total number of interconnections between particles divided by the total number of particles involved. The results indicate a close correlation between the electrocatalytic activities of Pt/MWCNTs catalysts and the interconnectivity of Pt NPs on MWCNTs. The electrocatalytic activity of the Pt/MWCNTs was found to first increase linearly and then level off with the interconnectivity of Pt NPs on MWCNTs. The optimum interconnectivity of Pt NPs on MWCNTs is ∼3, which corresponds to a Pt loading of 50 wt % in the Pt/MWCNTs. The reason for the enhanced catalysis with increased interconnectivity of Pt NPs is considered to be associated with a significant increase in the number of grain boundaries, which are considered to contain the active sites for the fuel cell reactions.
Obstructive sleep apnoea is the periodic reduction (hypopnoea) or cessation (apnoea) of breathing due to narrowing or occlusion of the upper airway during sleep. The main symptom is daytime ...sleepiness and it has been suggested it is linked to premature death, hypertension, ischaemic heart disease, stroke and road traffic accidents.
The main treatment for sleep apnoea is with the use of continuous positive airways pressure (CPAP), which requires a flow generator and mask. These are used at night to prevent apnoea, hypoxia and sleep disturbance. The objective was to assess the effects of CPAP in the treatment of obstructive sleep apnoea in adults.
We searched the Cochrane Airways Group Trials Register and reference lists of articles. We consulted experts in the field. Searches were current to July 2005.
We included randomised trials comparing nocturnal CPAP with an inactive control or oral appliances in adults with obstructive sleep apnoea (an apnoea and hypopnoea index greater than five per hour). Trials had a minimum intervention period of two weeks.
Trial quality was assessed and two review authors extracted data independently. Study authors were contacted for missing information. Parallel and crossover group trials were analysed separately.
Thirty-six trials involving 1718 people met the inclusion criteria. Study quality was mixed. Compared with control, CPAP showed significant improvements in objective and subjective sleepiness and several quality of life, cognitive function and depression measures (parallel-group studies: Epworth sleepiness scale (ESS) -3.83 units, 95% CI -4.57 to -3.09; crossover studies: ESS -1.84 units, 95% CI -2.57 to -1.11). Twenty-four hour systolic and diastolic blood pressures were lower with CPAP compared with control (parallel-group trials). Compared with oral appliances, CPAP significantly reduced the apnoea and hypopnoea index (crossover studies: -7.97 events/hr, 95% CI -9.56 to -6.38) and improved sleep efficiency (crossover studies: 2.31%, 95% CI 0.02 to 4.6) and minimum oxygen saturation (4.14%, 95% CI 3.25 to 5.03). Responders to both treatments expressed a strong preference for the oral appliance. However, participants were more likely to withdraw on OA than on CPAP therapy.
CPAP is effective in reducing symptoms of sleepiness and improving quality of life measures in people with moderate and severe obstructive sleep apnoea (OSA). It is more effective than oral appliances in reducing respiratory disturbances in these people but subjective outcomes are more equivocal. Certain people tend to prefer oral appliances to CPAP where both are effective. This could be because they offer a more convenient way of controlling OSA. Short-term data indicate that CPAP leads to lower blood pressure than in controls. Long-term data are required for all outcomes in order to determine whether the initial benefits seen in short-term clinical trials persist.
Background
Obstructive sleep apnoea is the periodic reduction (hypopnoea) or cessation (apnoea) of breathing due to narrowing or occlusion of the upper airway during sleep. The main symptom is ...daytime sleepiness and it has been suggested it is linked to premature death, hypertension, ischaemic heart disease, stroke and road traffic accidents.
Objectives
The main treatment for sleep apnoea is with the use of continuous positive airways pressure (CPAP), which requires a flow generator and mask. These are used at night to prevent apnoea, hypoxia and sleep disturbance. The objective was to assess the effects of CPAP in the treatment of obstructive sleep apnoea in adults.
Search methods
We searched the Cochrane Airways Group Trials Register and reference lists of articles. We consulted experts in the field. Searches were current to July 2005.
Selection criteria
We included randomised trials comparing nocturnal CPAP with an inactive control or oral appliances in adults with obstructive sleep apnoea (an apnoea and hypopnoea index greater than five per hour). Trials had a minimum intervention period of two weeks.
Data collection and analysis
Trial quality was assessed and two review authors extracted data independently. Study authors were contacted for missing information. Parallel and crossover group trials were analysed separately.
Main results
Thirty‐six trials involving 1718 people met the inclusion criteria. Study quality was mixed. Compared with control, CPAP showed significant improvements in certain objective and subjective sleepiness, measures of quality of life and cognitive function (parallel‐group studies: Epworth sleepiness scale (ESS) ‐3.83 units, 95% CI ‐4.57 to ‐3.09; crossover studies: ESS ‐1.84 units, 95% CI ‐2.57 to ‐1.11). Twenty‐four hour systolic and diastolic blood pressures were lower with CPAP compared with control (parallel‐group trials). Compared with oral appliances, CPAP significantly reduced the apnoea and hypopnoea index (crossover studies: ‐7.97 events/hr, 95% CI ‐9.56 to ‐6.38) and improved sleep efficiency (crossover studies: 2.31%, 95% CI 0.02 to 4.6) and minimum oxygen saturation (4.14%, 95% CI 3.25 to 5.03). Responders to both treatments expressed a strong preference for the oral appliance. However, participants were more likely to withdraw on OA than on CPAP therapy.
Authors' conclusions
CPAP is effective in reducing symptoms of sleepiness and improving quality of life measures in people with moderate and severe obstructive sleep apnoea (OSA). It is more effective than oral appliances in reducing respiratory disturbances in these people but subjective outcomes are more equivocal. Certain people tend to prefer oral appliances to CPAP where both are effective. This could be because they offer a more convenient way of controlling OSA. Short‐term data indicate that CPAP leads to lower blood pressure than control. Long‐term data are required for all outcomes in order to determine whether the initial benefits seen in short‐term clinical trials persist.
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