New Opportunities and Untapped Scientific Potential in the Abyssal Ocean

The abyssal ocean covers more than half of the Earth’s surface, yet remains understudied and underappreciated. In this Perspectives article, we mark the occasion of the Deep Submergence Vehicle Alvin’s increased depth range (from 4500 to 6500 m) to highlight the scientific potential of the abyssal seafloor. From a geologic perspective, ultra-slow spreading mid-ocean ridges, Petit Spot volcanism, transform faults, and subduction zones put the full life cycle of oceanic crust on display in the abyss, revealing constructive and destructive forces over wide ranges in time and space. Geochemically, the abyssal pressure regime influences the solubility of constituents such as silica and carbonate, and extremely high-temperature fluid-rock reactions in the shallow subsurface lead to distinctive and potentially unique geochemical profiles. Microbial residents range from low-abundance, low-energy communities on the abyssal plains to fast growing thermophiles at hydrothermal vents. Given its spatial extent and position as an intermediate zone between coastal and deep hadal settings, the abyss represents a lynchpin in global-scale processes such as nutrient and energy flux, population structure, and biogeographic diversity. Taken together, the abyssal ocean contributes critical ecosystem services while facing acute and diffuse anthropogenic threats from deep-sea mining, pollution, and climate change

Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV

A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.Comment: Submitted to Physics Letters

Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV

The Lambda(b) differential production cross section and the cross section ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7 TeV using data collected by the CMS experiment at the LHC. The measurements are based on Lambda(b) decays reconstructed in the exclusive final state J/Psi Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and Lambda to proton pion, using a data sample corresponding to an integrated luminosity of 1.9 inverse femtobarns. The product of the cross section times the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls faster than that of b mesons. The measured value of the cross section times the branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06 +/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are statistical and systematic, respectively.Comment: Submitted to Physics Letters

Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV

A search is presented for physics beyond the standard model (BSM) in final states with a pair of opposite-sign isolated leptons accompanied by jets and missing transverse energy. The search uses LHC data recorded at a center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to an integrated luminosity of approximately 5 inverse femtobarns. Two complementary search strategies are employed. The first probes models with a specific dilepton production mechanism that leads to a characteristic kinematic edge in the dilepton mass distribution. The second strategy probes models of dilepton production with heavy, colored objects that decay to final states including invisible particles, leading to very large hadronic activity and missing transverse energy. No evidence for an event yield in excess of the standard model expectations is found. Upper limits on the BSM contributions to the signal regions are deduced from the results, which are used to exclude a region of the parameter space of the constrained minimal supersymmetric extension of the standard model. Additional information related to detector efficiencies and response is provided to allow testing specific models of BSM physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO

Measurement of isolated photon production in pp and PbPb collisions at sqrt(sNN) = 2.76 TeV

Isolated photon production is measured in proton-proton and lead-lead collisions at nucleon-nucleon centre-of-mass energies of 2.76 TeV in the pseudorapidity range |eta|<1.44 and transverse energies ET between 20 and 80 GeV with the CMS detector at the LHC. The measured ET spectra are found to be in good agreement with next-to-leading-order perturbative QCD predictions. The ratio of PbPb to pp isolated photon ET-differential yields, scaled by the number of incoherent nucleon-nucleon collisions, is consistent with unity for all PbPb reaction centralities.Comment: Submitted to Physics Letters

The TRUFFLE study; fetal monitoring indications for delivery in 310 IUGR infants with 2 year's outcome delivered before 32 weeks of gestation.

OBJECTIVE: In the TRUFFLE study on outcome of early fetal growth restriction women were allocated to three timing of delivery plans according to antenatal monitoring strategies based on reduced computerized cardiotocographic heart rate short term variation (c-CTG STV) , early Ductus Venosus (DV p95) or late DV (DV noA) changes. However, many infants were per protocol delivered because of 'safety net' criteria, or for maternal indications, or 'other fetal indications' or after 32 weeks of gestation when the protocol was not applied anymore. It was the objective of the present post-hoc sub-analysis to investigate the indications for delivery in relation to outcome at 2 years in infants delivered before 32 weeks, to come to a further refinement of management proposals. METHODS: we included all 310 cases of the TRUFFLE study with known outcome at 2 years corrected age and 7 perinatal and infant deaths, apart from 7 cases with an inevitable death. Data were analyzed according to the randomization allocation and specified for the intervention indication. RESULTS: overall only 32% of fetuses born alive were delivered according to the specified monitoring parameter for indication for delivery. 38% were delivered because of safety net criteria, 15% because of other fetal reasons and 15% because of maternal reasons. In the c-CTG arm 51% of infants were delivered because of reduced STV. In the DV p95 arm 34% were delivered because of an abnormal DV and in the DV no A wave arm only 10% of cases were delivered accordingly. The majority of fetuses in the DV arms delivered for safety net criteria were delivered because of spontaneous decelerations. Two year's intact survival was highest in the combined DV arms as compared to the c-CTG arm (p = 0.05 when life born, p = 0.21 including fetal death), with no difference between the DV arms. Poorer outcome in the c-CTG arm was restricted to fetuses delivered because of decelerations in the safety net subgroup. Infants delivered because of maternal reasons had the highest birth weight and a non-significant higher intact survival. CONCLUSIONS: In this sub-analysis of fetuses delivered before 32 weeks the majority of infants were delivered for other reasons than according to the allocated CTG or DV monitoring strategy. Since in the DV arms CTG criteria were used as safety net criteria, but in the c-CTG arms no DV safety net criteria were applied, we speculate that the slightly poorer outcome in the CTG arm might be explained by absence of DV data. Optimal timing of delivery of the early IUGR fetus may therefore best be achieved by monitoring them longitudinally with DV and CTG monitoring

Longitudinal study of computerised cardiotocography in early fetal growth restriction.

OBJECTIVES: To explore if in early fetal growth restriction (FGR) the longitudinal pattern of short-term fetal heart rate (FHR) variation (STV) can be used for identifying imminent fetal distress and if abnormalities of FHR registration associate with two-year infant outcome. METHODS: The original TRUFFLE study assessed if in early FGR the use of ductus venosus Doppler pulsatility index (DVPI), in combination with a safety-net of very low STV and / or recurrent decelerations, could improve two-year infant survival without neurological impairment in comparison to computerised cardiotocography (cCTG) with STV calculation only. For this secondary analysis we selected women, who delivered before 32 weeks, and who had consecutive STV data for more than 3 days before delivery, and known infant two-year outcome data. Women who received corticosteroids within 3 days of delivery were excluded. Individual regression line algorithms of all STV values except the last one were calculated. Life table analysis and Cox regression analysis were used to calculate the day by day risk for a low STV or very low STV and / or FHR decelerations (DVPI group safety-net) and to assess which parameters were associated to this risk. Furthermore, it was assessed if STV pattern, lowest STV value or recurrent FHR decelerations were associated with two-year infant outcome. RESULTS: One hundred and fourty-nine women matched the inclusion criteria. Using the individual STV regression lines prediction of a last STV below the cCTG-group cut-off had a sensitivity of 0.42 and specificity of 0.91. For each day after inclusion the median risk for a low STV(cCTG criteria) was 4% (Interquartile range (IQR) 2% to 7%) and for a very low STV and / or recurrent decelerations (DVPI safety-net criteria) 5% (IQR 4 to 7%). Measures of STV pattern, fetal Doppler (arterial or venous), birthweight MoM or gestational age did not improve daily risk prediction usefully. There was no association of STV regression coefficients, a last low STV or /and recurrent decelerations with short or long term infant outcomes. CONCLUSION: The TRUFFLE study showed that a strategy of DVPI monitoring with a safety-net delivery indication of very low STV and / or recurrent decelerations could increase infant survival without neurological impairment at two years. This post-hoc analysis demonstrates that in early FGR the day by day risk of an abnormal cCTG as defined by the DVPI protocol safety-net criteria is 5%, and that prediction of this is not possible. This supports the rationale for cCTG monitoring more often than daily in these high-risk fetuses. Low STV and/or recurrent decelerations were not associated with adverse infant outcome and it appears safe to delay intervention until such abnormalities occur, as long as DVPI is in the normal range

How to monitor pregnancies complicated by fetal growth restriction and delivery below 32 weeks: a post-hoc sensitivity analysis of the TRUFFLE-study.

OBJECTIVES: In the recent TRUFFLE study it appeared that, in pregnancies complicated by fetal growth restriction (FGR) between 26 and 32 weeks, monitoring of the ductus venosus (DV) combined with computerised cardiotocography (cCTG) as a trigger for delivery, increased the chance of infant survival without neurological impairment. However, concerns in interpretation were raised as DV monitoring appeared associated with a non-significant increase in fetal death, and part of the infants were delivered after 32 weeks, after which the study protocol was no longer applied. This secondary sensitivity analysis focuses on women who delivered before 32 completed weeks, and analyses fetal death cases in detail. METHODS: We analysed the monitoring data of 317 women who delivered before 32 weeks, excluding women with absent infant outcome data or inevitable perinatal death. The association of the last monitoring data before delivery and infant outcome was assessed by multivariable analysis. RESULTS: The primary outcome (two year survival without neurological impairment) occurred more often in the two DV groups (both 83%) than in the CTG-STV group (77%), however the difference was not statistically significant (p = 0.21). Nevertheless, in surviving infants 93% was free of neurological impairment in the DV groups versus 85% in the CTG-STV group (p = 0.049). All fetal deaths (n = 7) occurred in women allocated to DV monitoring, which explains this difference. Assessment of the monitoring parameters that were obtained shortly before fetal death in these 7 cases showed an abnormal CTG in only one. Multivariable regression analysis of factors at study entry demonstrated that higher gestational age, larger estimated fetal weight 50th percentile ratio and lower U/C ratio were significantly associated with the (normal) primary outcome. Allocation to the DV groups had a smaller effect, but remained in the model (p < 0.1). Assessment of the last monitoring data before delivery showed that in the CTG-STV group abnormal fetal arterial Doppler was significantly associated with adverse outcome. In contrast, in the DV groups an abnormal DV was the only fetal monitoring parameter that was associated with adverse infant outcome, while fetal arterial Doppler, STV below CTG-group cut-off or recurrent fetal heart rate decelerations were not. CONCLUSIONS: In accordance with the results of the overall TRUFFLE study of the monitoring-intervention management of very early severe FGR we found that the difference in the proportion of infants surviving without neuroimpairment (the primary endpoint) was non-significant when comparing timing of delivery with or without changes in the DV waveform. However, the uneven distribution of fetal deaths towards the DV groups was likely by chance, and among surviving children neurological outcomes were better. Before 32 weeks, delaying delivery until abnormalities in DVPI or STV and/or recurrent decelerations occur, as defined by the study protocol, is therefore probably safe and possibly benefits long-term outcome

Search for leptophobic Z ' bosons decaying into four-lepton final states in proton-proton collisions at root s=8 TeV

Peer reviewe