Systematic errors in strong gravitational lensing reconstructions, a numerical simulation perspective

We present the analysis of a sample of twenty-four SLACS-like galaxy-galaxy strong gravitational lens systems with a background source and deflectors from the Illustris-1 simulation. We study the degeneracy between the complex mass distribution of the lenses, substructures, the surface brightness distribution of the sources, and the time delays. Using a novel inference framework based on Approximate Bayesian Computation, we find that for all the considered lens systems, an elliptical and cored power-law mass density distribution provides a good fit to the data. However, the presence of cores in the simulated lenses affects most reconstructions in the form of a Source Position Transformation. The latter leads to a systematic underestimation of the source sizes by 50 per cent on average, and a fractional error in $H_{0}$ of around $25_{-19}^{+37}$ per cent. The analysis of a control sample of twenty-four lens systems, for which we have perfect knowledge about the shape of the lensing potential, leads to a fractional error on $H_{0}$ of $12_{-3}^{+6}$ per cent. We find no degeneracy between complexity in the lensing potential and the inferred amount of substructures. We recover an average total projected mass fraction in substructures of $f_{\rm sub}<1.7-2.0\times10^{-3}$ at the 68 per cent confidence level in agreement with zero and the fact that all substructures had been removed from the simulation. Our work highlights the need for higher-resolution simulations to quantify the lensing effect of more realistic galactic potentials better, and that additional observational constraint may be required to break existing degeneracies.Comment: Accepted by MNRA

Extreme events in Italy from documentary sources: Venice as a case study

Venice risks to be submerged as a consequence of two problems: local land subsidence and sea level rise due to global warming. They both contribute to what is referred as Apparent Sea Level Rise (ASLR). Flooding Tides (locally: Acqua Alta) submerge Venice with an exponentially increasing frequency. The Acqua Alta is generated by a number of factors, the main of them being the Sirocco wind blowing over the Adriatic Sea, that ultimately displaces waters towards Venice. These extreme events have been investigated by using the documentary description of past floods, accurately reported over the last millennium, and tide gauge records for the recent period. A fundamental problem is to know the trend of the ASLR, possibly distinguishing between land subsidence and sea level components. Instrumental data go back to 1872 and a key point is to extend ourkno wledge back in time. Long-term ASLR has been investigated with the help of a biological indicator, i.e. the height of the green belt of the algae that live in the tidal range and whose upper front shows the average high tide level. Fortunately, in the first half of the 18th century, this indicator was accurately drawn by the famous painter Antonio Canaletto (1697-1768) and his pupils, mainly Bernardo Bellotto (1722-1780), in their photographic paintings made with an optical camera obscura. It has been possible to compare the tidal level, as it was in the 1700s and today. After careful spot investigation and minor corrections for some changes to the hydrological system occurred in the meantime, the bulk submersion of Venice estimated from the paintings is 61 ± 11 cm with average yearly trend 1.9 mm y−1

Pharmacokinetic Characterisation and Comparison of Bioavailability of Intranasal Fentanyl, Transmucosal, and Intravenous Administration through a Three-Way Crossover Study in 24 Healthy Volunteers

Background. For more than 60 years, the synthetic opioid fentanyl has been widely used in anaesthesia and analgesia. While the intravenous formulation is primarily used for general anaesthesia and intensive care settings, the drug’s high lipophilic properties also allow various noninvasive routes of administration. Published data suggest that intranasal administration is also attractive for use as intranasal patient-controlled analgesia (PCA). A newly developed intranasal fentanyl formulation containing 47 μg fentanyl, intravenous fentanyl, and oral transmucosal fentanyl citrate were characterised, and bioavailability was compared to assess the suitability of the intranasal formulation for an intranasal PCA product. Methods. 27 healthy volunteers were enrolled in a single-centre, open-label, randomised (order of treatments), single-dose study in a three-period crossover design. The pharmacokinetics of one intranasal puff of fentanyl formulation (47 μg, 140 mL per puff), one short intravenous infusion of 50 μg fentanyl, and one lozenge with an integrated applicator (200 μg fentanyl) were studied, and bioavailability was calculated. Blood samples were collected over 12 hours, and plasma concentrations of fentanyl were determined by HPLC with MS/MS detection. Results. 24 volunteers completed the study. The geometric mean of AUC0-tlast was the highest with oral transmucosal administration (1106 h  pg/ml, CV% = 32.86), followed by intravenous (672 h  pg/ml, CV% = 32.18) and intranasal administration (515 h  pg/ml, CV% = 30.10). Cmax was 886 pg/ml (CV% = 59.38) for intravenous, 338 pg/ml (CV% = 45.61) for intranasal, and 310 pg/ml (CV% = 29.58) for oral transmucosal administration. tmax was shortest for intravenous administration (0.06 h, SD = 0.056), followed by intranasal (0.21 h, SD = 0.078) and oral transmucosal administration (1.20 h, SD = 0.763). Dose-adjusted absolute bioavailability was determined to be 74.70% for the intranasal formulation and 41.25% for the oral transmucosal product. In total, 38 adverse events (AEs) occurred. Fourteen AEs were potentially related to the investigational items. No serious AE occurred. Conclusion. Pharmacokinetic parameters and bioavailability of the investigated intranasal fentanyl indicated suitability for its intended use as an intranasal PCA option

Detecting low-mass haloes with strong gravitational lensing I: the effect of data quality and lensing configuration

This paper aims to quantify how the lowest halo mass that can be detected with galaxy-galaxy strong gravitational lensing depends on the quality of the observations and the characteristics of the observed lens systems. Using simulated data, we measure the lowest detectable NFW mass at each location of the lens plane, in the form of detailed sensitivity maps. In summary, we find that: (i) the lowest detectable mass Mlow decreases linearly as the signal-to-noise ratio (SNR) increases and the sensitive area is larger when we decrease the noise; (ii) a moderate increase in angular resolution (0.07′′ versus 0.09′′) and pixel scale (0.01′′ versus 0.04′′) improves the sensitivity by on average 0.25 dex in halo mass, with more significant improvement around the most sensitive regions; (iii) the sensitivity to low-mass objects is largest for bright and complex lensed galaxies located inside the caustic curves and lensed into larger Einstein rings (i.e rE ≥ 1.0′′). We find that for the sensitive mock images considered in this work, the minimum mass that we can detect at the redshift of the lens lies between 1.5 × 108 and 3 × 109 M☉. We derive analytic relations between Mlow, the SNR and resolution and discuss the impact of the lensing configuration and source structure. Our results start to fill the gap between approximate predictions and real data and demonstrate the challenging nature of calculating precise forecasts for gravitational imaging. In light of our findings, we discuss possible strategies for designing strong lensing surveys and the prospects for HST, Keck, ALMA, Euclid and other future observations

Sharp - VII. New constraints on the dark matter free-streaming properties and substructure abundance from gravitationally lensed quasars

We present an analysis of seven strongly gravitationally lensed quasars and the corresponding constraints on the properties of dark matter. Our results are derived by modelling the lensed image positions and flux-ratios using a combination of smooth macro-models and a population of low-mass haloes within the mass range of 106-109 M☉. Our lens models explicitly include higher order complexity in the form of stellar discs and luminous satellites, as well as low-mass haloes located along the observed lines of sight for the first time. Assuming a cold dark matter (CDM) cosmology, we infer an average total mass fraction in substructure of fsub = 0.012+−00007004 (68 per cent confidence limits), which is in agreement with the predictions from CDM hydrodynamical simulations to within 1σ. This result is closer to the predictions than those from previous studies that did not include line-of-sight haloes. Under the assumption of a thermal relic dark matter model, we derive a lower limit on the particle relic mass of mth &gt; 5.58 keV (95 per cent confidence limits), which is consistent with a value of mth &gt; 5.3 keV from the recent analysis of the Ly α forest. We also identify two main sources of possible systematic errors and conclude that deeper investigations in the complex structure of lens galaxies as well as the size of the background sources should be a priority for this field

Chronic obstructive pulmonary disease (COPD) in elderly subjects: impact on functional status and quality of life

AbstractChronic obstructive pulmonary disease (COPD) is an important cause of morbidity and disability. Many studies have investigated factors influencing quality of life (QoL) in middle-aged COPD sufferers, but little attention has been given to elderly COPD. The aim of the present study was to investigate the impact of COPD on QoL and functional status in the elderly. Sixty COPD patients and 58 healthy controls over 65 years old were administered Pulmonary Function Tests, 6min Walking Test (6MWD) for exercise tolerance, the Barthel Index and Mini Mental State Examination (MMSE) for functional status, the Geriatric Depression Scale (GDS) for mood, and the Saint George Respiratory Questionnaire (SGRQ) for QoL. FEV1 and P aO2 were reduced in COPD patients. Also the distance walked during 6MWD was significantly shorter for patients than controls (282.5±89.5 vs. 332.9±95.2m; P<0.01). Moreover, COPD patients had significantly worse outcomes for the Barthel Index, GDS and SGRQ. The logistic regression model demonstrated that a decrease in FEV1 is the factor most strictly related to the deterioration of QoL in COPD patients. Mood was also an independent factor influencing QoL. In conclusion, elderly COPD patients show a substantial impairment in QoL depending on the severity of airway obstruction; symptoms related to the disease may be exaggerated by mood deflection

Associations between cardiac arrhythmia, incident disability in activities of daily living and physical performance: the ILSA study

Background: Cardiac arrhythmias are common conditions in older people. Unfortunately, there is limited literature on associations between cardiac arrhythmias and physical performance or disability. We therefore aimed to prospectively investigate associations between cardiac arrhythmias and changes in disability and physical performance during 8 years of follow-up, using data from the Italian Longitudinal Study on Aging (ILSA). Methods: Cardiac arrhythmias diagnosis was posed through a screening phase, confirmed by a physician. The onset of disability in activities of daily living (ADL) and the changes in several physical performance tests during follow-up were considered as outcomes. Fully-adjusted and propensity-score Cox Proportional Hazard models and mixed models were used for exploring associations between cardiac arrhythmia and the outcomes of interest. Results: The prevalence of cardiac arrhythmia at baseline was 23.3%. People reporting cardiac arrhythmia at the baseline were significantly older, more frequently male, smokers and reported a higher presence of all medical conditions investigated (hypertension, heart failure, angina, myocardial infarction, diabetes, stroke), but no difference in dementia, Parkinsonism, cognitive or mood disorder. Cardiac arrhythmia at baseline was significantly associated with the incidence of disability in ADL (HR = 1.23; 95%: CI: 1.01–1.50; P = 0.0478 in propensity score analyses; HR = 1.28; 95% CI: 1.01–1.61; P = 0.0401 in fully adjusted models). Cardiac arrhythmia at baseline was also associated with a significant worsening in balance test (P = 0.0436). Conclusions: The presence of cardiac arrhythmia at baseline was associated with a significant higher risk of disability and of worsening in some physical performance tests, particularly those relating to balance. Screening and frequently assessing physical performance in older people affected by cardiac arrhythmia can be important to prevent a loss of physical performance, with further, potential, complications of medical management