Search for black holes and other new phenomena in high-multiplicity final states in proton-proton collisions at root s=13 TeV

Peer reviewe

Search for a heavy bottom-like quark in pp collisions at √s =7 TeV

This is the Pre-Print version of the Article. The official published version of the paper can be accessed from the link below - Copyright @ 2011 Elsevier.A search for pair-produced bottom-like quarks in pp collisions at sqrt(s) = 7 TeV is conducted with the CMS experiment at the LHC. The decay b' to tW is considered in this search. The b' b'-bar to tW^- t-bar W^+ process can be identified by the distinctive signature of trileptons and same-sign dileptons. With a data sample corresponding to an integrated luminosity of 34 inverse picobarns, no excess above the standard model background predictions is observed and a b' quark with a mass between 255 and 361 GeV/c^2 is excluded at the 95% confidence level.This work is supported by the FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTD (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)

First observation of forward Z→bbˉZ \rightarrow b \bar{b} production in pppp collisions at s=8\sqrt{s}=8 TeV

The decay Z→bb¯ is reconstructed in pp collision data, corresponding to 2 fb −1 of integrated luminosity, collected by the LHCb experiment at a centre-of-mass energy of s=8 TeV. The product of the Z production cross-section and the Z→bb¯ branching fraction is measured for candidates in the fiducial region defined by two particle-level b -quark jets with pseudorapidities in the range 2.220 GeV and dijet invariant mass in the range 4520$GeV and dijet invariant mass in the range$45 < m_{jj} < 165$GeV. From a signal yield of$5462 \pm 763$$Z \rightarrow b \bar{b}$events, where the uncertainty is statistical, a production cross-section times branching fraction of$332 \pm 46 \pm 59$pb is obtained, where the first uncertainty is statistical and the second systematic. The measured significance of the signal yield is 6.0 standard deviations. This measurement represents the first observation of the$Z \rightarrow b \bar{b}$production in the forward region of$pp$ collisions

Understanding the health effects of ambient ultrafine particles.

Perspectives 3 is the third of a series produced by HEI to describe and interpret results from HEI and other research bearing on important and timely issues for a broad audience interested in environmental health. Perspectives 3 focuses on the health effects of ambient ultrafine particles (UFPs) and was developed under the guidance of a special HEI Review Panel.&nbsp; It examines the contribution of motor vehicles within the broader context of the multiple sources of ambient UFPs, explores the evidence from experimental studies in animals and in humans, as well as observational epidemiologic studies of people exposed to UFPs in the environment. It also identifies some of the broader lessons about both the specific health effects associated with exposures to UFPs and possible directions for future studies that could enhance our understanding of emissions, exposures, and effects of UFPs

Subacute effects of ozone exposure on cultivated human respiratory mucosa

This study was designed to investigate subacute effects of long-term exposure of both healthy and chronically inflamed human respiratory mucosa to ozone. Functional and metabolic effects on ciliary beat frequency (CBF), release of interleukin 8 (IL-8), interleukin 4 (IL-4), and gamma interferon (g-INF), as,well as cellular viability and cytotoxicity: were monitored Cell cultures of 60 specimens (healthy mucosa: n = 30 inflamed mucosa: n = 30) Mere exposed to synthetic air and to ozone-enriched synthetic air in different concentrations of 100, 500 and 1000 mug/m(3). Continuous expositions were performed using an air/liquid interface cell culture technique for a period of 4 weeks. CBF was monitored using video-interference contrast microscopy and cytokine release was quantified by enzyme immunoassays. Cellular,viability and cytotoxicity were controled by measuring lactate dehydrogenase activity: cytosolic activity of esterases, and by staining of nuclear DNA. Synthetic air had no influence on CBF during the 4 weeks of exposure. IL-8 release was continuously diminished in unaffected and in chronically inflamed mucosa. within the first week of continuous exposure with any ozone concentration neither CBF nor release of IL-8 were affected in healthy or in inflamed mucosa. During the second and the following weeks of exposure CBF and the release of L-8 were reduced in both tissues. Release of IL-4 or g-INF were not detectable at any time during the 4 weeks of ozone exposure. At higher ozone concentrations of 500 and 1000 mug/m(3) there was an increase of cytotoxicity which was greater in chronically inflamed than in healthy mucosa. In conclusion, ozone had no measurable effect on those parameters measured in human upper respiratory epithelium after one week of in vitro exposure to different concentrations. but did after longer periods of exposure. Chronically inflamed mucosa had a tendency toward a higher susceptibility to intermediate and high concentrations of ozone that did not reach a level of statistical significance under the conditions used in this study

ECG parameters and exposure to carbon ultrafine particles in young healthy subjects.

The mechanisms underlying the association between air pollution and cardiovascular morbidity and mortality are unknown. This study aimed to determine whether controlled exposure to elemental carbon ultrafine particles (UFP) affects electrocardiogram (ECG) parameters describing heart rate variability; repolarization duration, morphology, and variability; and changes in the ST segment. Two separate controlled studies (12 subjects each) were performed using a crossover design, in which each subject was exposed to filtered air and carbon UFP for 2 hours. The first protocol involved 2 exposures to air and 10 g/m3 ( 2 106 particles/cm3, count median diameter 25 nm, geometric standard deviation 1.6), at rest. The second protocol included 3 exposures to air, 10, and 25 g/m3 UFP ( 7 106 particles/cm3), with repeated exercise. Each subject underwent a continuous digital 12-lead ECG Holter recording to analyze the above ECG parameters. Repeated measures analysis of variance (ANOVA) was used to compare tested parameters between exposures. The observed responses to UFP exposure were small and generally not significant, although there were trends indicating an increase in parasympathetic tone, which is most likely also responsible for trends toward ST elevation, blunted QTc shortening, and increased variability of T-wave complexity after exposure to UFP. Recovery from exercise showed a blunted response of the parasympathetic system after exposure to UFP in comparison to air exposure. In conclusion, transient exposure to 10-25 g/m3 ultrafine carbon particles does not cause marked changes in ECG-derived parameters in young healthy subjects. However, trends are observed indicating that some subjects might be susceptible to air pollution, with a response involving autonomic modulation of the heart and repolarization of the ventricular myocardium