An embedding technique to determine ττ backgrounds in proton-proton collision data

An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

Performance of missing transverse momentum reconstruction in proton-proton collisions at root s=13 TeV using the CMS detector

The performance of missing transverse momentum ((p) over right arrow (miss)(T)) reconstruction algorithms for the CMS experiment is presented, using proton-proton collisions at a center-of-mass energy of 13 TeV, collected at the CERN LHC in 2016. The data sample corresponds to an integrated luminosity of 35.9 fb(-1). The results include measurements of the scale and resolution of (p) over right arrow (miss)(T), and detailed studies of events identified with anomalous (p) over right arrow (miss)(T). The performance is presented of a (p) over right arrow (miss)(T) reconstruction algorithm that mitigates the effects of multiple proton-proton interactions, using the "pileup per particle identification" method. The performance is shown of an algorithm used to estimate the compatibility of the reconstructed (p) over right arrow (miss)(T) with the hypothesis that it originates from resolution effects.Peer reviewe

A 1700-year n-alkanes hydrogen isotope record of moisture changes in sediments from Lake Sugan in the Qaidam Basin, northeastern Tibetan Plateau

We present a hydrogen isotopic record of long-chain n-alkanes in Lake Sugan to reconstruct regional moisture changes in the last 1700 years at a sampling resolution of 25 years. The D values decreased by over 30 parts per thousand from the Medieval Warm Period&#39; (MWP; c. ad 600-1500) to the Little Ice Age&#39; (LIA; c. ad 1500-1850), and indicated that the moisture pattern included a relatively humid climate before the MWP, becoming drier overall in the MWP, wetter in the LIA, and then tending towards drought in the post-industrial era. In the study region, Chenopodiceae shrubs were more abundant in dry climates than in wet. Meanwhile, D values of shrubs were more positive than those of grasses. Therefore, we suggest that the vegetation type (shrub or grass), which depends on moisture changes, is the controlling factor for D variations in Lake Sugan.</p

A tree-ring based precipitation reconstruction for the Baluntai region on the southern slope of the central Tien Shan Mountains, China, since AD 1464

July-June precipitation has been reconstructed back to A.D. 1464 for the Baluntai region on the southern slope of the central Tien Shan Mountains, China, using the Picea schrenkiana tree-ring width. The reconstruction explains the variance of 51% in the observed precipitation from 1959 to 2005. By employing a 21-year moving average to the reconstruction, nine periods with above average reconstructed precipitation comprised similar to 1474-1503, 1550-1577, 1588-1619, 1658-1713, 1790-1812, 1833-1867, 1890-1907, 1923-1944, and 1988-1995 similar to; eight periods with below average reconstruction consisted of 1504-1549, 1578-1587, 1620-1657, 1714-1789, 1813-1832, 1868-1889, 1908-1922 and 1945-1987. The wet/dry periods of the reconstructed precipitation correspond well with other reconstructions. Some droughts in the historical documents are also precisely captured in the reconstruction. Precipitation variations for the southern slope of the central Tien Shan Mountains are roughly synchronous with that of the northern slope in the recent -300 year. Power spectral and wavelet analysis demonstrated the existence of significant similar to 100-y, similar to 60-y, similar to 50-y, similar to 16-y, similar to 10-y and similar to 2-y cycles of variability.</p

Emissions of polycyclic aromatic hydrocarbons from coking industries in China

This study set out to assess the characteristics of polycyclic aromatic hydrocarbon (PAH) emission from coking industries, with field samplings conducted at four typical coke plants. For each selected plant, stack flue gas samples were collected during processes that included charging coal into the ovens (CC), pushing coke (PC) and the combustion of coke-oven gas (CG). Sixteen individual PAHs on the US EPA priority list were analyzed by gas chromatography/mass spectrometry (GC/MS). Results showed that the total PAH concentrations in the flue gas ranged from 45.776 to 414.874 mu g/m(3), with the highest emission level for CC (359.545 mu g/m(3)). The concentration of PAH emitted from the CC process in CP1 (stamp charging) was lower than that from CP3 and CP4 (top charging). Low-molecular-weight PAHs (i.e., two- to three-ring PAHs) were predominant contributors to the total PAH contents, and Nap, AcPy, Flu, PhA, and AnT were found to be the most abundant ones. Total BaPeq concentrations for CC (2.248 mu g/m(3)) were higher than those for PC (1.838 mu g/m(3)) and CG (1.082 mu g/m(3)), and DbA was an important contributor to carcinogenic risk as BaP in emissions from coking processes. Particulate PAH accounted for more than 20% of the total BaPeq concentrations, which were significantly higher than the corresponding contributions to the total PAH mass concentration (5%). Both particulate and gaseous PAH should be taken into consideration when the potential toxicity risk of PAH pollution during coking processes is assessed. The mean total-PAH emission factors were 346.132 and 93.173 mu g/kg for CC and PC, respectively.</p

Diagnosis and management of resistant hypertension: state of the art.

Resistant hypertension is defined as a lack of ambulatory blood pressure response to optimized medical treatment after exclusion of secondary hypertension in patients who are fully adherent to antihypertensive therapy. Patients with resistant hypertension are at high risk of complications, particularly cardiovascular events, and optimization of medical treatment remains the cornerstone of their management. Such optimization should be based on simple algorithms and include the use of aldosterone antagonists. The available data from clinical trials do not support the use of device-based approaches such as renal denervation, baroreflex activation therapy or arteriovenous anastomosis for the treatment of resistant hypertension in the majority of patients. Therefore, device treatment remains a last-resort for patients with truly resistant hypertension in the context of clinical research in highly skilled tertiary referral centres. Future research should focus on improving understanding of the intrinsic (physiological and psychological factors) and extrinsic (environmental stressors) mechanisms that contribute to a lack of response to blood-pressure-lowering drugs in adherent patients. The use of biomarkers to identify patients with early target organ damage and new technologies, such as renal nerve stimulation, to predict blood pressure responses to renal denervation could aid the selection of patients who might benefit from device therapies