Coupled vessel and moonpool responses in regular and irregular waves

Hydrodynamic coupling between the ship and moonpool responses is investigated. Dedicated experiments are carried out in the Ocean Basin at Sintef Ocean. Three different moonpool sizes are studied, where the moonpool length is 1/20, 1/10 and 1/2 of the ship length. The two former are square moonpools, while the latter is a rectangular moonpool with a width 1/2 of the ship’s beam. Numerical simulations are carried out using WAMIT. The coupling between the ship and moonpool is seen to be highly dependent on the volume of the moonpool relative to the submerged ship volume. WAMIT greatly over-predicts the moonpool responses in the proximity of resonance, which indicates that wave radiation damping is small, and that damping due to flow separation at sharp edges at the moonpool entrance is dominant. Two main nonlinear effects are observed; Swirling-type sloshing and secondary resonance. These nonlinear effects are excited in a range of wave periods where it is expected that a realistic sea environment will contain significant wave energy. This is most prominent in the largest moonpool. The piston mode shape in freely floating conditions is signficantly different relative to the one in forced heave.publishedVersio

On natural modes in moonpools and gaps in finite depth

In this paper an extension of the theoretical model of Molin (J. Fluid Mech., vol. 430, 2001, pp. 27–50) is proposed, where the assumptions of infinite depth and infinite horizontal extent of the support are released. The fluid domain is decomposed into two subdomains: the moonpool (or the gap) and a lower subdomain bounded by the seafloor and by an outer cylinder where the linearized velocity potential is assumed to be nil. Eigenfunction expansions are used to describe the velocity potential in both subdomains. Garrett’s method is then applied to match the velocity potentials at the common boundary and an eigenvalue problem is formulated and solved, yielding the natural frequencies and associated modal shapes of the free surface. Applications are made, first in the case of a circular moonpool, then in the rectangular gap and moonpool cases. Based on so-called single-mode approximations, simple formulas are proposed that give the resonant frequencies

An upright bottomless vertical cylinder with baffles floating in waves

Damping of the surge and pitch motions, as well as the first lateral sloshing mode in a rigid free-floating upright circular dock with bilge boxes and open bottom is investigated. Model tests are carried out on a 0.80 m diameter model in regular waves with wave periods near the highest natural sloshing period, and the internal free-surface elevation and model’s rigid body motions are measured. Perforated and solid annular baffles of relatively small widths are also installed inside the dock at various submergences. The experimental results are compared to a semi-analytical approach, where a three-dimensional domain decomposition method based on linear potential flow theory is adopted to calculate the hydrodynamic coefficients and exciting forces in heave, surge and pitch. A reduced natural sloshing frequency, as well as a damping ratio estimated from the energy dissipated due to flow separation from the baffles, are introduced in the free-surface boundary conditions to model the effects of the baffle. It shows good agreement with experimental data when the ratio between the draft of the baffle and the internal radius of the cylinder is dB/α = 0.27, and tends to under-predict the damping ratio for shallower drafts, most likely due to free-surface interactions. The solid baffle damps the sloshing response most efficiently, reducing the amplitude at the resonant peak by more than 56%

Clinico-biological factors predicting the benefit of the LV5FU2 maintenance strategy as a first-line therapy in patients with metastatic pancreatic cancer

International audienceIntroduction Predictive markers of LV5FU2 maintenance benefit after first-line induction with FOLFIRINOX in patients with metastatic pancreatic cancer are necessary to select patients who will not be harmed by this strategy. Patients and Methods We focused on patients who received 12 cycles of FOLFIRINOX (arm A, N = 88) or 8 cycles of FOLFIRINOX followed by LV5FU2 maintenance in controlled patients (arm B, N = 91) from the PRODIGE-35 trial. Prognostic factors and predictors of efficiency were identified by using Cox regression. Median progression-free survival (PFS), overall survival (OS), and time to deterioration of quality of life (TTD-QoL) were evaluated. Results Poor independent prognostic factors were primary tumor in place, age <65 years and the presence of liver metastases for PFS, a baseline neutrophil/lymphocyte ratio (NLR) ≥5 and CA19.9 ≥500 UI/L for OS, independent of the treatment arm. Patients with one metastatic site had a longer PFS in arm A, whereas patients with ≥2 metastatic sites had a longer PFS in arm B. We also identified predictors of OS and TTD-QoL in arm B but these differences were not statistically significant. Conclusion Except for patients with one metastatic site who benefited more from 12 cycles of FOLFIRINOX, a maintenance strategy with LV5FU2 should be widely offered to mPC patients whose survival and QoL are preserved after 4 months of FOLFIRINOX. (ClinicalTrials.gov: NCT02352337)

Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

Background: Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods: In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality. Findings: Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42·4% vs 44·2%; absolute difference -1·69 [-9·58 to 6·11] p=0·67; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5-8] vs 6 [5-8] cm H2O; p=0·0011). ICU mortality was higher in MICs than in HICs (30·5% vs 19·9%; p=0·0004; adjusted effect 16·41% [95% CI 9·52-23·52]; p<0·0001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0·80 [95% CI 0·75-0·86]; p<0·0001). Interpretation: Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status

Elliptic anisotropy measurement of the f0_0(980) hadron in proton-lead collisions and evidence for its quark-antiquark composition

International audienceDespite the f$_0$(980) hadron having been discovered half a century ago, the question about its quark content has not been settled: it might be an ordinary quark-antiquark ($\mathrm{q\bar{q}}$) meson, a tetraquark ($\mathrm{q\bar{q}q\bar{q}}$) exotic state, a kaon-antikaon ($\mathrm{K\bar{K}}$) molecule, or a quark-antiquark-gluon ($\mathrm{q\bar{q}g}$) hybrid. This paper reports strong evidence that the f$_0$(980) state is an ordinary $\mathrm{q\bar{q}}$ meson, inferred from the scaling of elliptic anisotropies ($v_2$) with the number of constituent quarks ($n_\mathrm{q}$), as empirically established using conventional hadrons in relativistic heavy ion collisions. The f$_0$(980) state is reconstructed via its dominant decay channel f$_0$(980) $\to$$\pi^+\pi^-$, in proton-lead collisions recorded by the CMS experiment at the LHC, and its $v_2$ is measured as a function of transverse momentum ($p_\mathrm{T}$). It is found that the $n_q$ = 2 ($\mathrm{q\bar{q}}$ state) hypothesis is favored over $n_q$ = 4 ($\mathrm{q\bar{q}q\bar{q}}$ or $\mathrm{K\bar{K}}$ states) by 7.7, 6.3, or 3.1 standard deviations in the $p_\mathrm{T}$$\lt$ 10, 8, or 6 GeV/$c$ ranges, respectively, and over $n_\mathrm{q}$ = 3 ($\mathrm{q\bar{q}g}$ hybrid state) by 3.5 standard deviations in the $p_\mathrm{T}$$\lt$ 8 GeV/$c$ range. This result represents the first determination of the quark content of the f$_0$(980) state, made possible by using a novel approach, and paves the way for similar studies of other exotic hadron candidates

Extracting the speed of sound in the strongly interacting matter created in ultrarelativistic lead-lead collisions at the LHC

International audienceUltrarelativistic nuclear collisions create a strongly interacting state of hot and dense quark-gluon matter that exhibits a remarkable collective flow behavior with minimal viscous dissipation. To gain deeper insights into its intrinsic nature and fundamental degrees of freedom, we extracted the speed of sound in this medium created using lead-lead (PbPb) collisions at a center-of-mass energy per nucleon pair of 5.02 TeV. The data were recorded by the CMS experiment at the CERN LHC and correspond to an integrated luminosity of 0.607 nb$^{-1}$. The measurement is performed by studying the multiplicity dependence of the average transverse momentum of charged particles emitted in head-on PbPb collisions. Our findings reveal that the speed of sound in this matter is nearly half the speed of light, with a squared value of 0.241 $\pm$ 0.002 (stat) $\pm$ 0.016 (syst) in natural units. The effective medium temperature, estimated using the mean transverse momentum, is 219 $\pm$ 8 (syst) MeV. The measured squared speed of sound at this temperature aligns precisely with predictions from lattice quantum chromodynamic (QCD) calculations. This result provides a stringent constraint on the equation of state of the created medium and direct evidence for a deconfined QCD phase being attained in relativistic nuclear collisions

Measurement of multijet azimuthal correlations and determination of the strong coupling in proton-proton collisions at s\sqrt{s} = 13 TeV

International audienceA measurement is presented of a ratio observable that provides a measure of the azimuthal correlations among jets with large transverse momentum $p_\mathrm{T}$. This observable is measured in multijet events over the range of $p_\mathrm{T}$ = 360-3170 GeV based on data collected by the CMS experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 134 fb$^{-1}$. The results are compared with predictions from Monte Carlo parton-shower event generator simulations, as well as with fixed-order perturbative quantum chromodynamics (pQCD) predictions at next-to-leading-order (NLO) accuracy obtained with different parton distribution functions (PDFs) and corrected for nonperturbative and electroweak effects. Data and theory agree within uncertainties. From the comparison of the measured observable with the pQCD prediction obtained with the NNPDF3.1 NLO PDFs, the strong coupling at the Z boson mass scale is $\alpha_\mathrm{S}(m_\mathrm{Z})$ = 0.1177 $\pm$ 0.0013 (exp) $_{-0.0073}^{+0.0116}$ (theo) = 0.1177$_{-0.0074}^{+0.0117}$, where the total uncertainty is dominated by the scale dependence of the fixed-order predictions. A test of the running of $\alpha_\mathrm{S}(m_\mathrm{Z})$ in the TeV region shows no deviation from the expected NLO pQCD behaviour