Evidence for X(3872) in Pb-Pb Collisions and Studies of its Prompt Production at sqrt[s_{NN}]=5.02 TeV

The first evidence for X(3872) production in relativistic heavy ion collisions is reported. The X(3872) production is studied in lead-lead (Pb-Pb) collisions at a center-of-mass energy of sqrt[s_{NN}]=5.02  TeV per nucleon pair, using the decay chain X(3872)→J/ψπ^{+}π^{-}→μ^{+}μ^{-}π^{+}π^{-}. The data were recorded with the CMS detector in 2018 and correspond to an integrated luminosity of 1.7  nb^{-1}. The measurement is performed in the rapidity and transverse momentum ranges |y|<1.6 and 15<p_{T}<50  GeV/c. The significance of the inclusive X(3872) signal is 4.2 standard deviations. The prompt X(3872) to ψ2S yield ratio is found to be ρ^{Pb-Pb}=1.08±0.49(stat)±0.52(syst), to be compared with typical values of 0.1 for pp collisions. This result provides a unique experimental input to theoretical models of the X(3872) production mechanism, and of the nature of this exotic state.

Studies of Charm Quark Diffusion inside Jets Using Pb-Pb and pp Collisions at sqrt[s_{NN}]=5.02 TeV

The first study of charm quark diffusion with respect to the jet axis in heavy ion collisions is presented. The measurement is performed using jets with p_{T}^{jet}>60  GeV/c and D^{0} mesons with p_{T}^{D}>4  GeV/c in lead-lead (Pb-Pb) and proton-proton (pp) collisions at a nucleon-nucleon center-of-mass energy of sqrt[s_{NN}]=5.02  TeV, recorded by the CMS detector at the LHC. The radial distribution of D^{0} mesons with respect to the jet axis is sensitive to the production mechanisms of the meson, as well as to the energy loss and diffusion processes undergone by its parent parton inside the strongly interacting medium produced in Pb-Pb collisions. When compared to Monte Carlo event generators, the radial distribution in pp collisions is found to be well described by pythia, while the slope of the distribution predicted by sherpa is steeper than that of the data. In Pb-Pb collisions, compared to the pp results, the D^{0} meson distribution for 4<p_{T}^{D}<20  GeV/c hints at a larger distance on average with respect to the jet axis, reflecting a diffusion of charm quarks in the medium created in heavy ion collisions. At higher p_{T}^{D}, the Pb-Pb and pp radial distributions are found to be similar.

Measurements of tt[over ¯]H Production and the CP Structure of the Yukawa Interaction between the Higgs Boson and Top Quark in the Diphoton Decay Channel

The first observation of the tt[over ¯]H process in a single Higgs boson decay channel with the full reconstruction of the final state (H→γγ) is presented, with a significance of 6.6 standard deviations (σ). The CP structure of Higgs boson couplings to fermions is measured, resulting in an exclusion of the pure CP-odd structure of the top Yukawa coupling at 3.2σ. The measurements are based on a sample of proton-proton collisions at a center-of-mass energy sqrt[s]=13  TeV collected by the CMS detector at the LHC, corresponding to an integrated luminosity of 137  fb^{-1}. The cross section times branching fraction of the tt[over ¯]H process is measured to be σ_{tt[over ¯]H}B_{γγ}=1.56_{-0.32}^{+0.34}  fb, which is compatible with the standard model prediction of 1.13_{-0.11}^{+0.08}  fb. The fractional contribution of the CP-odd component is measured to be f_{CP}^{Htt}=0.00±0.33.

Measurement of the Jet Mass Distribution and Top Quark Mass in Hadronic Decays of Boosted Top Quarks in pp Collisions at sqrt[s]=13 TeV

A measurement is reported of the jet mass distribution in hadronic decays of boosted top quarks produced in pp collisions at sqrt[s]=13  TeV. The data were collected with the CMS detector at the LHC and correspond to an integrated luminosity of 35.9  fb^{-1}. The measurement is performed in the lepton+jets channel of tt[over ¯] events, where the lepton is an electron or muon. The products of the hadronic top quark decay t→bW→bqq[over ¯]^{'} are reconstructed as a single jet with transverse momentum larger than 400 GeV. The tt[over ¯] cross section as a function of the jet mass is unfolded at the particle level and used to extract a value of the top quark mass of 172.6±2.5  GeV. A novel jet reconstruction technique is used for the first time at the LHC, which improves the precision by a factor of 3 relative to an earlier measurement. This highlights the potential of measurements using boosted top quarks, where the new technique will enable future precision measurements.

Constraints on the χ_{c1} versus χ_{c2} Polarizations in Proton-Proton Collisions at sqrt[s]=8 TeV

The polarizations of promptly produced χ_{c1} and χ_{c2} mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at sqrt[s]=8  TeV. The χ_{c} states are reconstructed via their radiative decays χ_{c}→J/ψγ, with the photons being measured through conversions to e^{+}e^{-}, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_{c2} to χ_{c1} yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ→μ^{+}μ^{-} decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum.

Search for a Narrow Resonance Lighter than 200 GeV Decaying to a Pair of Muons in Proton-Proton Collisions at sqrt[s]=13 TeV

A search is presented for a narrow resonance decaying to a pair of oppositely charged muons using sqrt[s]=13  TeV proton-proton collision data recorded at the LHC. In the 45-75 and 110-200 GeV resonance mass ranges, the search is based on conventional triggering and event reconstruction techniques. In the 11.5-45 GeV mass range, the search uses data collected with dimuon triggers with low transverse momentum thresholds, recorded at high rate by storing a reduced amount of trigger-level information. The data correspond to integrated luminosities of 137 and 96.6  fb^{-1} for conventional and high-rate triggering, respectively. No significant resonant peaks are observed in the probed mass ranges. The search sets the most stringent constraints to date on a dark photon in the ∼30-75 and 110-200 GeV mass ranges.

Search for Supersymmetry with a Compressed Mass Spectrum in Events with a Soft τ Lepton, a Highly Energetic Jet, and Large Missing Transverse Momentum in Proton-Proton Collisions at sqrt[s]=13 TeV

The first search for supersymmetry in events with an experimental signature of one soft, hadronically decaying τ lepton, one energetic jet from initial-state radiation, and large transverse momentum imbalance is presented. These event signatures are consistent with direct or indirect production of scalar τ leptons (τ[over ˜]) in supersymmetric models that exhibit coannihilation between the τ[over ˜] and the lightest neutralino (χ[over ˜]_{1}^{0}), and that could generate the observed relic density of dark matter. The data correspond to an integrated luminosity of 77.2  fb^{-1} of proton-proton collisions at sqrt[s]=13  TeV collected with the CMS detector at the LHC in 2016 and 2017. The results are interpreted in a supersymmetric scenario with a small mass difference (Δm) between the chargino (χ[over ˜]_{1}^{±}) or next-to-lightest neutralino (χ[over ˜]_{2}^{0}), and the χ[over ˜]_{1}^{0}. The mass of the τ[over ˜] is assumed to be the average of the χ[over ˜]_{1}^{±} and χ[over ˜]_{1}^{0} masses. The data are consistent with standard model background predictions. Upper limits at 95% confidence level are set on the sum of the χ[over ˜]_{1}^{±}, χ[over ˜]_{2}^{0}, and τ[over ˜] production cross sections for Δm(χ[over ˜]_{1}^{±},χ[over ˜]_{1}^{0})=50  GeV, resulting in a lower limit of 290 GeV on the mass of the χ[over ˜]_{1}^{±}, which is the most stringent to date and surpasses the bounds from the LEP experiments.

Search for Physics beyond the Standard Model in Events with Overlapping Photons and Jets

Results are reported from a search for new particles that decay into a photon and two gluons, in events with jets. Novel jet substructure techniques are developed that allow photons to be identified in an environment densely populated with hadrons. The analyzed proton-proton collision data were collected by the CMS experiment at the LHC, in 2016 at sqrt[s]=13  TeV, and correspond to an integrated luminosity of 35.9  fb^{-1}. The spectra of total transverse hadronic energy of candidate events are examined for deviations from the standard model predictions. No statistically significant excess is observed over the expected background. The first cross section limits on new physics processes resulting in such events are set. The results are interpreted as upper limits on the rate of gluino pair production, utilizing a simplified stealth supersymmetry model. The excluded gluino masses extend up to 1.7 TeV, for a neutralino mass of 200 GeV and exceed previous mass constraints set by analyses targeting events with isolated photons.

Search for Low-Mass Quark-Antiquark Resonances Produced in Association with a Photon at sqrt[s]=13 TeV

A search for narrow low-mass resonances decaying to quark-antiquark pairs is presented. The search is based on proton-proton collision events collected at 13 TeV by the CMS detector at the CERN LHC. The data sample corresponds to an integrated luminosity of 35.9  fb^{-1}, recorded in 2016. The search considers the case where the resonance has high transverse momentum due to initial-state radiation of a hard photon. To study this process, the decay products of the resonance are reconstructed as a single large-radius jet with two-pronged substructure. The signal would be identified as a localized excess in the jet invariant mass spectrum. No evidence for such a resonance is observed in the mass range 10 to 125 GeV. Upper limits at the 95% confidence level are set on the coupling strength of resonances decaying to quark pairs. The results obtained with this photon trigger strategy provide the first direct constraints on quark-antiquark resonance masses below 50 GeV obtained at a hadron collider.

Search for a Light Charged Higgs Boson Decaying to a W Boson and a CP-Odd Higgs Boson in Final States with eμμ or μμμ in Proton-Proton Collisions at sqrt[s]=13 TeV

A search for a light charged Higgs boson (H^{+}) decaying to a W boson and a CP-odd Higgs boson (A) in final states with eμμ or μμμ is performed using data from pp collisions at sqrt[s]=13  TeV, recorded by the CMS detector at the LHC and corresponding to an integrated luminosity of 35.9  fb^{-1}. In this search, it is assumed that the H^{+} boson is produced in decays of top quarks, and the A boson decays to two oppositely charged muons. The presence of signals for H^{+} boson masses between 100 and 160 GeV and A boson masses between 15 and 75 GeV is investigated. No evidence for the production of the H^{+} boson is found. Upper limits at 95% confidence level are obtained on the combined branching fraction for the decay chain, t→bH^{+}→bW^{+}A→bW^{+}μ^{+}μ^{-}, of 1.9×10^{-6} to 8.6×10^{-6}, depending on the masses of the H^{+} and A bosons. These are the first limits for these decay modes of the H^{+} and A bosons.

Studies of Beauty Suppression via Nonprompt D^{0} Mesons in Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

The transverse momentum spectra of D^{0} mesons from b hadron decays are measured at midrapidity (|y|<1) in pp and Pb-Pb collisions at a nucleon-nucleon center of mass energy of 5.02 TeV with the CMS detector at the LHC. The D^{0} mesons from b hadron decays are distinguished from prompt D^{0} mesons by their decay topologies. In Pb-Pb collisions, the B→D^{0} yield is found to be suppressed in the measured p_{T} range from 2 to 100  GeV/c as compared to pp collisions. The suppression is weaker than that of prompt D^{0} mesons and charged hadrons for p_{T} around 10  GeV/c. While theoretical calculations incorporating partonic energy loss in the quark-gluon plasma can successfully describe the measured B→D^{0} suppression at higher p_{T}, the data show an indication of larger suppression than the model predictions in the range of 2<p_{T}<5  GeV/c.

Jet Shapes of Isolated Photon-Tagged Jets in Pb-Pb and pp Collisions at sqrt[s_{NN}]=5.02 TeV

The modification of jet shapes in Pb-Pb collisions, relative to those in pp collisions, is studied for jets associated with an isolated photon. The data were collected with the CMS detector at the LHC at a nucleon-nucleon center-of-mass energy of 5.02 TeV. Jet shapes are constructed from charged particles with track transverse momenta (p_{T}) above 1  GeV/c in annuli around the axes of jets with p_{T}^{jet}>30  GeV/c associated with an isolated photon with p_{T}^{γ}>60  GeV/c. The jet shape distributions are consistent between peripheral Pb-Pb and pp collisions, but are modified for more central Pb-Pb collisions. In these central Pb-Pb events, a larger fraction of the jet momentum is observed at larger distances from the jet axis compared to pp, reflecting the interaction between the partonic medium created in heavy ion collisions and the traversing partons.

Search for W Boson Decays to Three Charged Pions

For the first time, a search for the rare decay of the W boson to three charged pions has been performed. Proton-proton collision data recorded by the CMS experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 77.3  fb^{-1}, have been analyzed. No significant excess is observed above the background expectation. An upper limit of 1.01×10^{-6} is set at 95% confidence level on the branching fraction of the W boson to three charged pions. This provides a strong motivation for theoretical calculations of this branching fraction.

Combination immunosuppressant therapy and lupus nephritis outcome: a hospital-based study

Lupus nephritis (LN) is the leading cause of mortality in lupus patients. This study aimed to investigate the treatment outcome and renal histological risk factors of LN in a tertiary referral center. Between 2006 and 2017, a retrospective observational study enrolled 148 biopsy-proven LN patients. After propensity score matching, 75 cases were included for further analysis. The classification and scoring of LN were assessed according to the International Society of Nephrology/Renal Pathology Society. Treatment response was evaluated by daily urine protein and urinalysis at two years after commencing induction treatment and the development of end-stage renal disease (ESRD). In total, 50.7% patients achieved complete remission (CR) or partial remission (PR), while 49.3% patients were categorized as nonresponders. Therapeutic responses in terms of CR/PR rates were associated with Systemic Lupus Erythematosus Disease Activity Index scores (odds ratio (OR): 1.34, 95% confidence interval (CI): 1.12-1.60, p = 0.001). Moreover, higher baseline creatinine levels (hazard ratio (HR): 2.10, 95% CI: 1.29-3.40, p = 0.003), higher renal activity index (HR: 1.30, 95% CI: 1.07-1.58, p = 0.008) and chronicity index (HR: 1.40, 95% CI: 1.06-1.85, p = 0.017) predicted ESRD. Among pathological scores, cellular crescents (HR: 4.42, 95% CI: 1.01-19.38, p = 0.049) and fibrous crescents (HR: 5.93, 95% CI: 1.41-24.92, p = 0.015) were independent risk factors for ESRD. In conclusion, higher lupus activity was a good prognostic marker for renal remission. Renal histology was predictive of ESRD. Large-scale prospective studies are required to verify the efficacy of mycophenolate in combination with azathioprine or cyclosporine in LN patients.

Observation of Single Top Quark Production in Association with a Z Boson in Proton-Proton Collisions at sqrt[s]=13 TeV

The observation of single top quark production in association with a Z boson and a quark (tZq) is reported. Events from proton-proton collisions at a center-of-mass energy of 13 TeV containing three charged leptons (either electrons or muons) and at least two jets are analyzed. The data were collected with the CMS detector in 2016 and 2017 and correspond to an integrated luminosity of 77.4fb^{-1}. The increased integrated luminosity, a multivariate lepton identification, and a redesigned analysis strategy improve significantly the sensitivity of the analysis compared to previous searches for tZq production. The tZq signal is observed with a significance well over 5 standard deviations. The measured tZq production cross section is σ(pp→tZq→tℓ^{+}ℓ^{-}q)=111±13(stat)_{-9}^{+11}(syst)  fb, for dilepton invariant masses above 30 GeV, in agreement with the standard model expectation.

Observation of Two Excited B_{c}^{+} States and Measurement of the B_{c}^{+}(2S) Mass in pp Collisions at sqrt[s]=13 TeV

Signals consistent with the B_{c}^{+}(2S) and B_{c}^{*+}(2S) states are observed in proton-proton collisions at sqrt[s]=13  TeV, in an event sample corresponding to an integrated luminosity of 143  fb^{-1}, collected by the CMS experiment during the 2015-2018 LHC running periods. These excited b[over ¯]c states are observed in the B_{c}^{+}π^{+}π^{-} invariant mass spectrum, with the ground state B_{c}^{+} reconstructed through its decay to J/ψπ^{+}. The two states are reconstructed as two well-resolved peaks, separated in mass by 29.1±1.5(stat)±0.7(syst)  MeV. The observation of two peaks, rather than one, is established with a significance exceeding five standard deviations. The mass of the B_{c}^{+}(2S) meson is measured to be 6871.0±1.2(stat)±0.8(syst)±0.8(B_{c}^{+})  MeV, where the last term corresponds to the uncertainty in the world-average B_{c}^{+} mass.

Combination of Searches for Higgs Boson Pair Production in Proton-Proton Collisions at sqrt[s]=13 TeV

This Letter describes a search for Higgs boson pair production using the combined results from four final states: bbγγ, bbττ, bbbb, and bbVV, where V represents a W or Z boson. The search is performed using data collected in 2016 by the CMS experiment from LHC proton-proton collisions at sqrt[s]=13  TeV, corresponding to an integrated luminosity of 35.9  fb^{-1}. Limits are set on the Higgs boson pair production cross section. A 95% confidence level observed (expected) upper limit on the nonresonant production cross section is set at 22.2 (12.8) times the standard model value. A search for narrow resonances decaying to Higgs boson pairs is also performed in the mass range 250-3000 GeV. No evidence for a signal is observed, and upper limits are set on the resonance production cross section.

Search for Narrow Hγ Resonances in Proton-Proton Collisions at sqrt[s]=13 TeV

A search for heavy, narrow resonances decaying to a Higgs boson and a photon (Hγ) has been performed in proton-proton collision data at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9  fb^{-1} collected with the CMS detector at the LHC in 2016. Events containing a photon and a Lorentz-boosted hadronically decaying Higgs boson reconstructed as a single, large-radius jet are considered, and the γ+jet invariant mass spectrum is analyzed for the presence of narrow resonances. To increase the sensitivity of the search, events are categorized depending on whether or not the large-radius jet can be identified as a result of the merging of two jets originating from b quarks. Results in both categories are found to agree with the predictions of the standard model. Upper limits on the production rate of Hγ resonances are set as a function of their mass in the range of 720-3250 GeV, representing the most stringent constraints to date.

Search for the Higgs Boson Decaying to Two Muons in Proton-Proton Collisions at sqrt[s]=13 TeV

A search for the Higgs boson decaying to two oppositely charged muons is presented using data recorded by the CMS experiment at the CERN LHC in 2016 at a center-of-mass energy sqrt[s]=13  TeV, corresponding to an integrated luminosity of 35.9  fb^{-1}. Data are found to be compatible with the predicted background. For a Higgs boson with a mass of 125.09 GeV, the 95% confidence level observed (background-only expected) upper limit on the production cross section times the branching fraction to a pair of muons is found to be 3.0 (2.5) times the standard model expectation. In combination with data recorded at center-of-mass energies sqrt[s]=7 and 8 TeV, the background-only expected upper limit improves to 2.2 times the standard model value with a standard model expected significance of 1.0 standard deviation. The corresponding observed upper limit is 2.9 with an observed significance of 0.9 standard deviation. This corresponds to an observed upper limit on the standard model Higgs boson branching fraction to muons of 6.4×10^{-4} and to an observed signal strength of 1.0±1.0(stat)±0.1(syst).

Search for Dark Matter Particles Produced in Association with a Top Quark Pair at sqrt[s]=13 TeV

A search is performed for dark matter particles produced in association with a top quark pair in proton-proton collisions at sqrt[s]=13  TeV. The data correspond to an integrated luminosity of 35.9  fb^{-1} recorded by the CMS detector at the LHC. No significant excess over the standard model expectation is observed. The results are interpreted using simplified models of dark matter production via spin-0 mediators that couple to dark matter particles and to standard model quarks, providing constraints on the coupling strength between the mediator and the quarks. These are the most stringent collider limits to date for scalar mediators, and the most stringent for pseudoscalar mediators at low masses.

Search for Leptoquarks Coupled to Third-Generation Quarks in Proton-Proton Collisions at sqrt[s]=13 TeV

Three of the most significant measured deviations from standard model predictions, the enhanced decay rate for B→D^{(*)}τν, hints of lepton universality violation in B→K^{(*)}ℓℓ decays, and the anomalous magnetic moment of the muon, can be explained by the existence of leptoquarks (LQs) with large couplings to third-generation quarks and masses at the TeV scale. The existence of these states can be probed at the LHC in high energy proton-proton collisions. A novel search is presented for pair production of LQs coupled to a top quark and a muon using data at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9  fb^{-1}, recorded by the CMS experiment. No deviation from the standard model prediction has been observed and scalar LQs decaying exclusively into tμ are excluded up to masses of 1420 GeV. The results of this search are combined with those from previous searches for LQ decays into tτ and bν, which excluded scalar LQs below masses of 900 and 1080 GeV. Vector LQs are excluded up to masses of 1190 GeV for all possible combinations of branching fractions to tμ, tτ and bν. With this analysis, all relevant couplings of LQs with an electric charge of -1/3 to third-generation quarks are probed for the first time.

Evidence for the Associated Production of a Single Top Quark and a Photon in Proton-Proton Collisions at sqrt[s]=13 TeV

The first evidence of events consistent with the production of a single top quark in association with a photon is reported. The analysis is based on proton-proton collisions at sqrt[s]=13  TeV and recorded by the CMS experiment in 2016, corresponding to an integrated luminosity of 35.9  fb^{-1}. Events are selected by requiring the presence of a muon (μ), a photon (γ), an imbalance in transverse momentum from an undetected neutrino (ν), and at least two jets (j) of which exactly one is identified as associated with the hadronization of a b quark. A multivariate discriminant based on topological and kinematic event properties is employed to separate signal from background processes. An excess above the background-only hypothesis is observed, with a significance of 4.4 standard deviations. A fiducial cross section is measured for isolated photons with transverse momentum greater than 25 GeV in the central region of the detector. The measured product of the cross section and branching fraction is σ(pp→tγj)B(t→μνb)=115±17(stat)±30(syst)  fb, which is consistent with the standard model prediction.

Observation of the Z→ψℓ^{+}ℓ^{-} Decay in pp Collisions at sqrt[s]=13 TeV

This Letter presents the observation of the rare Z boson decay Z→ψℓ^{+}ℓ^{-}. Here, ψ represents contributions from direct J/ψ and ψ(2S)→J/ψX, ℓ^{+}ℓ^{-} is a pair of electrons or muons, and the J/ψ meson is detected via its decay to μ^{+}μ^{-}. The sample of proton-proton collision data, collected by the CMS experiment at the LHC at a center-of-mass energy of 13 TeV, corresponds to an integrated luminosity of 35.9  fb^{-1}. The signal is observed with a significance in excess of 5 standard deviations. After subtraction of the ψ(2S)→J/ψX contribution, the ratio of the branching fraction of the exclusive decay Z→J/ψℓ^{+}ℓ^{-} to the decay Z→μ^{+}μ^{-}μ^{+}μ^{-} within a fiducial phase space is measured to be B(Z→J/ψℓ^{+}ℓ^{-})/B(Z→μ^{+}μ^{-}μ^{+}μ^{-})=0.67±0.18(stat)±0.05(syst).

Search for Pair-Produced Resonances Each Decaying into at Least Four Quarks in Proton-Proton Collisions at sqrt[s]=13 TeV

This Letter presents the results of a search for pair-produced particles of masses above 100 GeV that each decay into at least four quarks. Using data collected by the CMS experiment at the LHC in 2015-2016, corresponding to an integrated luminosity of 38.2  fb^{-1}, reconstructed particles are clustered into two large jets of similar mass, each consistent with four-parton substructure. No statistically significant excess of data over the background prediction is observed in the distribution of average jet mass. Pair-produced squarks with dominant hadronic R-parity-violating decays into four quarks and with masses between 0.10 and 0.72 TeV are excluded at 95% confidence level. Similarly, pair-produced gluinos that decay into five quarks are also excluded with masses between 0.10 and 1.41 TeV at 95% confidence level. These are the first constraints that have been placed on pair-produced particles with masses below 400 GeV that decay into four or five quarks, bridging a significant gap in the coverage of R-parity-violating supersymmetry parameter space.

Observation of Higgs Boson Decay to Bottom Quarks

The observation of the standard model (SM) Higgs boson decay to a pair of bottom quarks is presented. The main contribution to this result is from processes in which Higgs bosons are produced in association with a W or Z boson (VH), and are searched for in final states including 0, 1, or 2 charged leptons and two identified bottom quark jets. The results from the measurement of these processes in a data sample recorded by the CMS experiment in 2017, comprising 41.3  fb^{-1} of proton-proton collisions at sqrt[s]=13  TeV, are described. When combined with previous VH measurements using data collected at sqrt[s]=7, 8, and 13 TeV, an excess of events is observed at m_{H}=125  GeV with a significance of 4.8 standard deviations, where the expectation for the SM Higgs boson is 4.9. The corresponding measured signal strength is 1.01±0.22. The combination of this result with searches by the CMS experiment for H→bb[over ¯] in other production processes yields an observed (expected) significance of 5.6 (5.5) standard deviations and a signal strength of 1.04±0.20.

Observation of the χ_{b1}(3P) and χ_{b2}(3P) and Measurement of their Masses

The χ_{b1}(3P) and χ_{b2}(3P) states are observed through their ϒ(3S)γ decays, using an event sample of proton-proton collisions collected by the CMS experiment at the CERN LHC. The data were collected at a center-of-mass energy of 13 TeV and correspond to an integrated luminosity of 80.0  fb^{-1}. The ϒ(3S) mesons are identified through their dimuon decay channel, while the low-energy photons are detected after converting to e^{+}e^{-} pairs in the silicon tracker, leading to a χ_{b}(3P) mass resolution of 2.2 MeV. This is the first time that the J=1 and 2 states are well resolved and their masses individually measured: 10513.42±0.41(stat)±0.18(syst)  MeV and 10524.02±0.57(stat)±0.18(syst)  MeV; they are determined with respect to the world-average value of the ϒ(3S) mass, which has an uncertainty of 0.5 MeV. The mass splitting is measured to be 10.60±0.64(stat)±0.17(syst)  MeV.

Elliptic Flow of Charm and Strange Hadrons in High-Multiplicity p+Pb Collisions at sqrt[s_{NN}]=8.16 TeV

The elliptic azimuthal anisotropy coefficient (v_{2}) is measured for charm (D^{0}) and strange (K_{S}^{0}, Λ, Ξ^{-}, and Ω^{-}) hadrons, using a data sample of p+Pb collisions collected by the CMS experiment, at a nucleon-nucleon center-of-mass energy of sqrt[s_{NN}]=8.16  TeV. A significant positive v_{2} signal from long-range azimuthal correlations is observed for all particle species in high-multiplicity p+Pb collisions. The measurement represents the first observation of possible long-range collectivity for open heavy flavor hadrons in small systems. The results suggest that charm quarks have a smaller v_{2} than the lighter quarks, probably reflecting a weaker collective behavior. This effect is not seen in the larger PbPb collision system at sqrt[s_{NN}]=5.02  TeV, also presented.

Constraining Gluon Distributions in Nuclei Using Dijets in Proton-Proton and Proton-Lead Collisions at sqrt[s_{NN}]=5.02 TeV

The pseudorapidity distributions of dijets as functions of their average transverse momentum (p_{T}^{ave}) are measured in proton-lead (pPb) and proton-proton (pp) collisions. The data samples were collected by the CMS experiment at the CERN LHC, at a nucleon-nucleon center-of-mass energy of 5.02 TeV. A significant modification of the pPb spectra with respect to the pp spectra is observed in all p_{T}^{ave} intervals investigated. The ratios of the pPb and pp distributions are compared to next-to-leading order perturbative quantum chromodynamics calculations with unbound nucleon and nuclear parton distribution functions (PDFs). These results give the first evidence that the gluon PDF at large Bjorken x in lead ions is strongly suppressed with respect to the PDF in unbound nucleons.

Observation of tt[over ¯]H Production

The observation of Higgs boson production in association with a top quark-antiquark pair is reported, based on a combined analysis of proton-proton collision data at center-of-mass energies of sqrt[s]=7, 8, and 13 TeV, corresponding to integrated luminosities of up to 5.1, 19.7, and 35.9  fb^{-1}, respectively. The data were collected with the CMS detector at the CERN LHC. The results of statistically independent searches for Higgs bosons produced in conjunction with a top quark-antiquark pair and decaying to pairs of W bosons, Z bosons, photons, τ leptons, or bottom quark jets are combined to maximize sensitivity. An excess of events is observed, with a significance of 5.2 standard deviations, over the expectation from the background-only hypothesis. The corresponding expected significance from the standard model for a Higgs boson mass of 125.09 GeV is 4.2 standard deviations. The combined best fit signal strength normalized to the standard model prediction is 1.26_{-0.26}^{+0.31}.

Search for Narrow Resonances in the b-Tagged Dijet Mass Spectrum in Proton-Proton Collisions at sqrt[s]=8 TeV

A search for narrow resonances decaying to bottom quark-antiquark pairs is presented, using a data sample of proton-proton collisions at sqrt[s]=8  TeV corresponding to an integrated luminosity of 19.7  fb^{-1}. The search is extended to masses lower than those reached in typical searches for resonances decaying into jet pairs at the LHC, by taking advantage of triggers that identify jets originating from bottom quarks. No significant excess of events is observed above the background predictions. Limits are set on the product of cross section and branching fraction to bottom quarks for spin 0, 1, and 2 resonances in the mass range of 325-1200 GeV. These results improve on the limits for resonances decaying into jet pairs in the 325-500 GeV mass range.

Observation of increases in emission from modern vehicles over time in Hong Kong using remote sensing

In this study on-road gaseous emissions of vehicles are investigated using remote sensing measurements collected over three different periods. The results show that a high percentage of gaseous pollutants were emitted from a small percentage of vehicles. Liquified Petroleum Gas (LPG) vehicles generally have higher gaseous emissions compared to other vehicles, particularly among higher-emitting vehicles. Vehicles with high vehicle specific power (VSP) tend to have lower CO and HC emissions while petrol and LPG vehicles tend to have higher NO emissions when engine load is high. It can be observed that gaseous emission factors of petrol and LPG vehicles increase greatly within 2 years of being introduced to the vehicle fleet, suggesting that engine and catalyst performance deteriorate rapidly. It can be observed that LPG vehicles have higher levels of gaseous emissions than petrol vehicles, suggesting that proper maintenance of LPG vehicles is essential in reducing gaseous emissions from vehicles.

On-board gaseous emissions of LPG taxis and estimation of taxi fleet emissions

Instantaneous CO, NO, and HC emissions and exhaust flow rates from four LPG taxis, which adhered to Euro 2-4 emission standards, were measured using a sophisticated portable emission measurement system (PEMS). Instantaneous air/fuel ratios, emission rates, and emission factors at different operating modes were derived to explore the emission characteristics of these four taxis. Results show that gaseous emissions from these four taxis exceed emission standards, due to extended vehicle use and poor maintenance. NO emissions from newer taxis are lower whilst CO and HC emissions of the Euro 4 taxi are similar to those of Euro 2 taxis during idling and low speed travel. The taxis emit lower amounts of gaseous pollutants whilst idling and emit the highest amounts of CO and NO whilst accelerating. Large fluctuations in air/fuel ratios can be observed from the Euro 4 taxi during idling, indicating a malfunction of fuel supply control to the engine. Such fluctuations are not observed from the other taxis. This shows that a Euro 4 taxi is not necessarily cleaner than a Euro 3 taxi. Emission factors derived from on-board measurements are applied to estimate gaseous emissions from the taxi fleet; these results show that emissions are higher during peak hour traffic conditions. An estimate of the taxi fleet's emissions whilst the older taxis are replaced is also calculated. It can be seen that faster replacement of older taxis can lead to reductions in gaseous emissions from the taxi fleet. This study shows that the PEMS is an adequate tool for measuring emissions from LPG vehicles and that there is an urgent need to enforce emission standards on taxis. This study also shows that on-board measurements should be incorporated in the estimation of emissions from other vehicle types. This would result in better emission estimations under local traffic conditions.

Antinucleosome antibodies as a potential biomarker for the evaluation of renal pathological activity in patients with proliferative lupus nephritis

The objective of this study is to evaluate the correlation between antinucleosome antibodies and renal pathological activity in patients with proliferative lupus nephritis (LN). We evaluated 36 patients with proliferative LN, 14 non-renal lupus patients and 10 healthy volunteers. Lupus activity was assessed using the British Isles Lupus Assessment Group 2004 (BILAG 2004) index, serum anti-double stranded DNA (anti-dsDNA) levels, serum complement levels and daily urinary protein levels. All 36 lupus nephritis patients received renal biopsy. Antinucleosome antibodies were detected by enzyme-linked immunosorbent assay (ELISA). Our results showed that levels of serum antinucleosome antibodies were significantly higher in LN patients (median 90.35 units/ml, interquartile range [IQR] 37.38–135.23) than in non-renal SLE patients (median 5.45 units/ml, IQR 2.6–28.93, p <0.05) and in healthy volunteers (median 3.35 units/ml, IQR 2.95–5.23, p <0.001). Serum levels of antinucleosome antibodies were positively correlated with BILAG index (Spearman’s r = 0.645, p <0.001) and serum anti-dsDNA antibody levels ( rs = 0.644, p <0.01), while serum levels of antinucleosome antibodies were negatively correlated with serum levels of C3 ( rs = -0.400, p <0.01) and C4 ( rs = -0.300, p <0.05). Serum levels of antinucleosome antibodies were positively correlated with the histological activity index of LN ( rs = 0.368, p <0.05). However, there was no significant correlation between serum levels of antinucleosome antibodies and the histological chronicity index. In conclusion, the serum level of antinucleosome antibodies is a potential biomarker for early recognition of renal involvement and evaluation of disease activity in SLE. Our preliminary results suggested that serum levels of antinucleosome antibodies might be a potential biomarker in evaluating pathological activity of LN.

Predictors for 5-year survival in a prospective cohort of elderly stroke patients

OBJECTIVES

To examine predictors for 5-year survival in elderly stroke patients.

MATERIALS AND METHODS

Prospective cohort study of 186 consecutive acute stroke patients aged ≥65 years admitted to Bankstown-Lidcombe Hospital, Australia 03/2002 to 03/2003. All subjects were followed up in 2007/8, at 5 years post-stroke, for outcome measures. Logistic regression analysis was performed to predict 5-year survival using covariables, including functional status, age, stroke type and severity and vascular risk factors. Patients lost to follow-up (n = 20) were excluded from the analyses.

RESULTS

One hundred patients (60%) were dead at study end. Predictors for survival in final logistic regression model were as follows: Glasgow Coma Scale (GCS) on admission (OR 1.49, 95%CI 1.1-2.0, P = 0.01), preadmission functional independence measure (FIM) score (OR 1.04, 95%CI 1.0-1.1, P = 0.01), age (OR 0.93, 95%CI 0.87-0.98, P = 0.01) and atrial fibrillation (OR 0.43, 95% CI 0.19-0.95, P = 0.04). For 5-year survivors, mean Modified Rankin Scale was 3.1 ± 1.5, total FIM score 85 ± 32, mini-mental state examination (MMSE) 22 ± 8 and Hospital Anxiety and Depression (HAD) scores 5.4 ± 3.4 and 5.2 ± 3.9, respectively. FIM cognition score was significantly lower at 5 years when compared to baseline (24 ± 8 vs 29 ± 8, P < 0.05) (all scores expressed as mean ± SD). In contrast, MMSE, HAD and total FIM scores were not significantly different at 5 years when compared to baseline.

CONCLUSIONS

The study identified lower GCS on admission, lower preadmission FIM score, age and atrial fibrillation as negative predictors for 5-year survival following stroke.

Meta-analysis of the cardiovascular benefits of intensive lipid lowering with statins

OBJECTIVE

To evaluate the efficacy of intensive lipid lowering with higher-dose statins.

METHODS

Meta-analysis of seven randomized controlled trials comprising 50,972 participants.

RESULTS

Mean follow-up was 3.1 years with mean age 63 years. Final LDL-C levels in intensive lipid-lowering group were 1.42-2.07 mmol/l compared to 2.1-3.5 mmol/l in the less intensive or control group. The intensive arm had significantly lower risks for stroke OR 0.80 (95% CI 0.71-0.89); major coronary events OR 0.74 (95% CI 0.65-0.83); cardiovascular disease (CVD) or coronary heart disease (CHD) deaths OR 0.84 (95% CI 0.74-0.95). Significantly higher liver enzyme abnormalities occurred in intensive group* (OR 3.96; 95% CI 2.08-7.53), but it was not associated with drug discontinuations (OR 1.20; 95% CI 0.88-1.64).

CONCLUSION

In those at high risk of cardiovascular events, intensive lipid lowering with statins to LDL-C level <2.1 mmol/l significantly reduces risk of stroke, major coronary events and CVD or CHD deaths compared to LDL-C level ≥ 2.1 mmol/l. [*Correction added on 11 January 2011 after first online publication on 27 October 2010. The phrase, "Significantly higher liver enzyme abnormalities occurred in less intensive group", was amended to "Significantly higher liver enzyme abnormalities occurred in intensive group".].

Development of emission factors and emission inventories for motorcycles and light duty vehicles in the urban region in Vietnam

This paper reports on a 2-year emissions monitoring program launched by the Centre for Environmental Monitoring of the Vietnam Environment Administration which aimed at determining emission factors and emission inventories for two typical types of vehicle in Hanoi, Vietnam. The program involves four major activities. A database for motorcycles and light duty vehicles (LDV) in Hanoi was first compiled through a questionnaire survey. Then, two typical driving cycles were developed for the first time for motorcycles and LDVs in Hanoi. Based on this database and the developed driving cycles for Hanoi, a sample of 12 representative test vehicles were selected to determine vehicle specific fuel consumption and emission factors (CO, HC, NOx and CO(2)). This set of emission factors were developed for the first time in Hanoi with due considerations of local driving characteristics. In particular, it was found that the emission factors derived from Economic Commission for Europe (ECE) driving cycles and adopted in some previous studies were generally overestimated. Eventually, emission inventories for motorcycles and LDVs were derived by combining the vehicle population data, the developed vehicle specific emission factors and vehicle kilometre travelled (VKT) information from the survey. The inventory suggested that motorcycles contributed most to CO, HC and NOx emissions while LDVs appeared to be more fuel consuming.

Rapid identification of allergenic and pathogenic molds in environmental air by an oligonucleotide array

Background

Airborne fungi play an important role in causing allergy and infections in susceptible people. Identification of these fungi, based on morphological characteristics, is time-consuming, expertise-demanding, and could be inaccurate.

Methods

We developed an oligonucleotide array that could accurately identify 21 important airborne fungi (13 genera) that may cause adverse health problems. The method consisted of PCR amplification of the internal transcribed spacer (ITS) regions, hybridization of the PCR products to a panel of oligonucleotide probes immobilized on a nylon membrane, and detection of the hybridization signals with alkaline phosphatase-conjugated antibodies.

Results

A collection of 72 target and 66 nontarget reference strains were analyzed by the array. Both the sensitivity and specificity of the array were 100%, and the detection limit was 10 pg of genomic DNA per assay. Furthermore, 70 fungal isolates recovered from air samples were identified by the array and the identification results were confirmed by sequencing of the ITS and D1/D2 domain of the large-subunit RNA gene. The sensitivity and specificity of the array for identification of the air isolates was 100% (26/26) and 97.7% (43/44), respectively.

Conclusions

Identification of airborne fungi by the array was cheap and accurate. The current array may contribute to decipher the relationship between airborne fungi and adverse health effect.

Removals of fly ash and NO in a fluidized-bed reactor with CuO/activated carbon catalysts

This study investigates the effects of fly ash compositions (SiO(2) and Al(2)O(3)), particle sizes (4-10 μm and 40 μm), and concentrations on the simultaneous removals of fly ash and NO using a fluidized-bed catalyst reactor. Experimental results show that the removal efficiencies of fly ash and NO at particle concentrations of 968-11,181 mg m(-3) are 71-97% and 42-57%, respectively. SiO(2) particles have more influences than Al(2)O(3) particles on the performances of fluidized-bed CuO/AC catalyst. As the concentration of fine particle increases, the pores and active sites on catalyst surface are obstructed and therefore the activities of catalysts are depressed.

Improved observer dependent perception of weak edges when scanning an image in real time indicated by introducing 1/f noise into the primary visual cortex V1. Theory and experimental support

We present results of a new process for generating 1/f type noise sequences and introducing the noise in the primary visual cortex which then enables improved perception of weak edges when an observer is scanning a complex image in real time to detect detail such as in mammogram reading sessions. It can be explained by an adaptation of information theory for functional rather than previous task-based methods for formulating processes for edge formation in early vision. This is enabled from a two "species" classification of the interaction of opposing on-centre and off-centre neuron processes. We show that non-stationary stochastic resonances predicted by theory can occur with 1/f noise in the primary visual cortex V1 and suggest that signalling exchanges between V1 and the lateral geniculate nucleus (LGN) of the thalamus can initiate neural activity for saccadic action (and observer attention) for weak edge perception. Improvements predicted by our theory were shown from 600 observations by two groups of observers of limited experience and an experienced radiologist for reference (but not for diagnosis). They scanned and rated the definition of microcalcification in clusters separately rated by the experienced radiologist. The results and supporting theory showed dependence on the observer's attention and orderly scanning. Using a compact simplified equipment configuration the methodology has important clinical applications for conjunction searches of features and for detection of objects in poor light conditions for vehicles.

Formaldehyde and volatile organic compounds in Hong Kong homes: concentrations and impact factors

This paper presents formaldehyde and volatile organic compounds (VOC) concentrations, potential sources and impact factors in 100 homes. The 24-h average formaldehyde concentration in 37 homes exceeded the good class of the Hong Kong Indoor Air Quality Objectives (HKIAQO), whereas the total VOCs concentration in all homes was lower than the HKIAQO. Compared to other East Asian cities, indoor formaldehyde and styrene in Hong Kong was the highest, reflecting that the homes in Hong Kong were more affected by household products and materials. The formaldehyde concentration in newly built apartments was significantly higher than that in old buildings, whereas no relationship between the concentration and the building age was found for VOCs. There was no difference for formaldehyde and toluene between smoking and non-smoking homes, suggesting that cigarette smoking was not the major source of these two species. Homes of a couple with a child had higher formaldehyde and acetic acid concentrations, while homes with more than three people had higher concentrations of 1-butanol, heptane and d-limonene. When shoes were inside the homes, heptane, acetic acid, nonane and styrene concentrations were statistically higher than that when shoes were out of the homes. Furthermore, higher levels of 1,2,4-trimethylbenzene, styrene, nonane and heptane were found in gas-use families rather than in electricity-use homes.

PRACTICAL IMPLICATIONS

Long-term exposure to formaldehyde and volatile organic compounds (VOC) in indoor environments may cause a number of adverse health effects such as asthma, dizziness, respiratory and lung diseases, and even cancers. Therefore, it is critical to minimize indoor air pollution caused by formaldehyde and VOCs. The findings obtained in this study would significantly enhance our understanding on the levels, emission sources and factors which affect indoor concentrations of formaldehyde and VOCs. The results can help housing designers, builders, home residents, and housing department of the government to improve indoor air quality (IAQ) by means of appropriate building materials, clean household products and proper life styles. It can also help policy makers reconcile the IAQ objectives and guidelines.

Could fetal bovine serum protect the small bowel from ischemia and reperfusion injury by using a systemic perfusion

The luminal perfusion of fetal bovine serum (FBS) has been reported to protect the small bowel from ischemia/reperfusion injury. We studied the effect of intravascular FBS infusion in a rat model of intestinal ischemia and reperfusion. Thirty male Lewis rats received an FBS (FBS group) or saline [control (CON) group] infusion through the vena cava. Fourteen days later (day 0), all rats underwent 2-hours total vascular occlusion in 15 cm of the intestine. Rats were killed on days 0, 3, and 6 to determine the intestinal morphology and DNA and protein content. After FBS perfusion, DNA and protein levels showed no significant increase. In both groups, the mucosa and weight of the intestine changed, but not significantly. The lung, spleen, and liver were congested. Mucosal morphology of the small intestine and DNA and protein content do not significantly change with FBS infusion. Reasons might be an insufficient dose of FBS or the short duration of intestinal ischemia. Systemically perfused FBS may also act as an antigen in some organs. The role of FBS in sysTemic perfusion requires further study.

Mammogram object detection using dendronic image analysis

Breast cancer can be treated with better patient outcomes and significantly lower costs if detected early. Using the spatial dendronic structure, image masks can be obtained, showing regions in the mammogram image corresponding to the breast and lead marker. The technique is robust to noise and placement of the breast within the image. The technique not only reduces the size of the region to be analysed, but also provides the dendronic structure of the breast in which stealth-like masses can be found more easily.

Association between setting quantified road safety targets and road fatality reduction

Since the 1980s, many countries have set quantified road safety targets as part of their comprehensive road safety strategies. This paper studies the association between the setting of quantified road safety targets and road fatality reduction over the past two decades. Both aggregate and disaggregate levels of hypothesis tests are performed on data from 14 countries that set road safety targets during the period 1981-1999. A before-and-after analysis of the treatment and comparison groups is conducted, and the results show that the majority of countries with quantified road safety targets experienced a reduction in road fatalities in this period. Overall, the establishment of quantified road safety targets is found to have an appreciable association with an improvement in road safety.

Long-term prognosis and factors affecting biliary atresia from experience over a 25 year period

BACKGROUND

The purpose of this study was to delineate the long-term prognosis and factors we have noted in our 25 years of experience treating patients suffering from biliary atresia (BA) who have undergone Kasai's operation.

METHODS

We studied 141 patients (69 male and 72 female infants) who underwent Kasai's operation at the National Taiwan University Hospital between 1976 and 2000. Factors analyzed included age at time of surgery, postoperative bile flow, frequency of cholangitis, prophylactic long-term oral antibiotics given, and intrahepatic biliary cyst formation.

RESULTS

The 5-year and 10-year survival rates for native liver patients were 34.8% (49/141) and 30.5% (43/141). If surgery was performed before the patient was 60 days old, the results were 44.8% (26/58) and 39.7% (23/58). Good bile flow occurred in 115 patients (81.6%) and 88 (62.4%) became jaundice-free. Cholangitis was encountered in 77 patients (54.6%) within the first two postoperative years. Prophylactic oral antibiotics lowered the rate of recurrent cholangitis (p = 0.011). Multiple intrahepatic biliary cysts occurred in 11.3% (16/141) of patients, who had a higher mortality rate when compared with the other patients (p = 0.037). The factors that had a positive effect include: (1) less than 60 days of age at time of surgery, (2) good bile flow, (3) low frequency of cholangitis, (4) long-term prophylactic antibiotics, and (5) no multiple intrahepatic cyst formation.

CONCLUSION

The long-term survival rate can be improved if Kasai's operation is performed early, there is a detailed dissection producing good bile flow, and long-term prophylactic antibiotics are given to prevent recurrent cholangitis and formation of multiple intrahepatic cysts.

Application of the mixed venous blood concentration equation in desflurane anesthesia

BACKGROUND

We have previously proposed an equation derived from Fick's law and Lin's concept of effective blood concentration (EBC) to calculate the mixed venous blood concentration (MVBC) of isoflurane. Desflurane has a lower blood/air partition coefficient than isoflurane and, as such, promotes a faster induction and recovery from anesthesia. In this study, we investigated the application of the MVBC equation to predict the MVBC of desflurane.

METHODS

We maintained anesthesia with a fixed inspired concentration (CI) of desflurane (10%) during cardiac anesthesia in 11 patients. In order to measure the real concentrations of desflurane in mixed venous blood, pulmonary arterial blood samples were collected at different time points via a Swan-Ganz catheter for gas chromatographic-mass spectrometric determination. The relationship between the calculated concentrations and the actual blood sample concentrations of desflurane in mixed venous blood was investigated. Lin's EBC method was also used and the results were compared with those of MVBC.

RESULTS

The calculations from our derived MVBC equation and the actual blood concentrations showed a similar kinetic pattern; the concentration levels were approximately the same and correlated well (r = 0.89) during anesthesia. However, the EBC method failed to accurately estimate the actual blood concentrations.

CONCLUSIONS

The results demonstrate that our equation, but not the EBC method, may be useful for estimating pulmonary blood concentrations of desflurane. The clinical significance and the importance of the method merit further investigation.

Identifying the determinants of 1-year post-stroke outcomes in elderly patients

OBJECTIVES

To examine 12-month outcomes and develop predictive models for outcomes in elderly stroke patients.

METHODS

Prospective study of 186 consecutive acute stroke patients aged > or = 65 years admitted to a local hospital between March 2002 and March 2003. Outcome measurements included mortality, functional independence measure (FIM) score and nursing home placement. Two predictive models, using multiple logistic regression analysis, were developed to identify the factors associated with (i) mortality, and (ii) being alive and independent (defined as mean FIM score > or = 90) at 12 months.

RESULTS

One hundred and seventy two (92%) patients were followed up at 12 months post-stroke. Mortality rate was 31%, and was significantly higher in nursing home vs non-nursing home origin patients (68% [15/22] vs 25% [38/150]). Nursing home placement for non-nursing home origin survivors was 28% (31/112). Age > or = 85 years was associated with higher mortality (odds ratio = 5.3, 95% confidence interval = 1.8-15, P < 0.01) and lower FIM for patients living at home pre-stroke. Predictive models showed that age, not living at home pre-stroke, pre-stroke FIM < 108, inability to walk on admission, dysphasia, visual field loss and haemorrhagic stroke were associated with worse outcome.

CONCLUSIONS

Predictive models--by developing new strategies to improve outcomes through identifying treatable predictive factors--may be clinically useful in elderly stroke patients.

Comparison of childhood hepatic malignancies in a hepatitis B hyper-endemic area

AIM: To examine the differences of clinical behaviors between hepatocellular carcinomas (HCC) and hepatoblastomas (HB) in children.

METHODS: From 1979 to 1997, we collected 73 HCC and 54 HB from two major medical centers in Taiwan. Demog-raphic, laboratory and radiological data, and survival curves were statistically compared.

RESULTS: HCC clinically differed from HB in mean age (10.6 vs 2.5 years; P < 0.001), status of hepatitis B infection (56/56 vs 4/35, P < 0.001) and accompanying liver cirrhosis (26/40 vs 0/30, P < 0.001), portal vein thrombi (22/56 vs 5/38, P = 0.006) and para-aortic lymphadenopathy (10/56 vs 1/38, P = 0.026). Due to a higher recurrence rate (7/12 vs 2/13, P = 0.041), stage I HCC compared poorly in survivals with stage I HB (P = 0.0183). Chemotherapy could only benefit HB as evidenced by 66.7% of resectability conversion and improve survivals for advanced HB, even with unsuccessful conversion. The survival difference between stage I HB and advanced HB with delayed complete resection was of borderline insignificance (P = 0.0507).

CONCLUSION: HCC and HB were preliminarily distinguishable by some clinical clues. Delayed resection after chemotherapy was only possible for HB. However, further studies are needed to strengthen our observation that appropriate reliance upon chemotherapy to subsequently resect advanced HB could achieve the comparable survival to that of stage I HB.

Application of MVBC equation to predict mixed venous blood concentrations of sevoflurane in cardiac anaesthesia

We have proposed an equation for estimating the real-time mixed venous blood concentration (MVBC) of isoflurane in cardiac anaesthesia. However, information related to the application of our method to sevoflurane is lacking. We studied 12 patients undergoing cardiac surgery and anaesthetised with sevoflurane. At different time points, pulmonary arterial blood samples were collected for gas chromatography-mass spectrometry (GC-MS) to determine the real mixed venous concentrations of sevoflurane. The inspired and expired concentrations of sevoflurane, measured by a gas monitor, were used for the MVBC calculations. Using Bland-Altman analyses, we found that the calculated MVBCs accurately represent the actual concentrations of sevoflurane in pulmonary arterial blood, as shown by a near-zero percentage bias with a 0.14% precision between the two concentrations. The results demonstrated that our equation could be a useful method for estimating the pulmonary blood concentration of sevoflurane.

Would relaxing speed limits aggravate safety? A case study of Hong Kong

This paper studies the effect of the changed speed limits on accident counts for major roadways in the urban environment of Hong Kong. In 1999-2002, the speed limits of a number of sections of roadway were reviewed and increased. Nineteen of them were major roadways. Their speed limits were raised by 10-20 km/h from 50 to 70 km/h. Before and after studies were carried out to investigate the changes in accident counts with respect to the set of carefully chosen comparison groups. Qualification tests for these comparison groups were conducted to confirm their suitability for the studies. In the majority of the treatment sites, the accident counts were worse after the increase in speed limits, both for the category of fatal, serious and slight (FSS) accidents, and for the category of fatal and serious (FS) accidents. Overall, the relaxation of the speed limit from 50 to 70 km/h increased the FSS accident counts by 15% and the FS accident counts by 1%. The relaxation of the speed limit from 70 to 80 km/h increased the FSS accident counts by 18% and the FS accident counts by 36%.

Prevalence of Parkinson's disease in Sydney

OBJECTIVE

To examine the prevalence of Parkinson's disease (PD) in Bankstown, Sydney, using the same methodology as a previous study in Randwick, Sydney, Australia (1998-1999).

PARTICIPANTS AND METHODS

Twenty census districts (CDs) for the Bankstown local government area were randomly selected. Research personnel door-knocked every household within the CDs to locate people aged > or =55 years. A structured questionnaire (containing four screening questions for PD) was administered to those agreeing to participate. Screened positive participants were invited to come for a clinical examination. This is a continuation of the previous study and data have been combined.

RESULTS

Combining data for Bankstown and Randwick gave 1028 participants; crude prevalence, 780 per 100,000 (CI: 546-1077). In Bankstown, there were 501 participants aged > or =55 years (response rate 70%); 135 were screened positive with 101 (74.8%) agreeing to a clinical examination. The prevalence of PD in the Bankstown community was 3.4% (17 of 501) (95% CI: 1.98-5.43) for those aged > or =55 years; crude prevalence 776 per 100,000 (CI: 452-1241).

CONCLUSION

The combined results of two Sydney studies appear to indicate that Sydney has one of the highest prevalence estimates of PD in developed countries.