Fractional flow reserve and instantaneous wave-free ratio in coronary artery bypass grafting: a meta-analysis and practice review

Objective

Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) are invasive methods to assess the functional significance of intermediate severity coronary lesions. Both indexes have been extensively validated in clinical trials in guiding revascularisation in patients with stable ischaemic heart disease undergoing percutaneous coronary intervention (PCI) with improved clinical outcomes. However, the role of these tools in coronary artery bypass grafting (CABG) is less clear.

Methods

A meta-analysis of randomised trials and observational studies was carried out to help in determining the optimal strategy for assessing lesion severity and selecting graft targets in patients undergoing CABG. Electronic searches were carried out on Embase, MEDLINE, and Web of Science. A group of four authors independently screened and then assessed the retrieved records. Cochrane's Risk of Bias and Robins-I tools were used for bias assessment. A survey was conducted among surgeons and cardiologists to describe current attitudes towards the preoperative use of functional coronary investigations in practice.

Results

Clinical outcomes including mortality at 30 days, perioperative myocardial infarction, number of grafts, incidence of stroke, rate of further need for revascularisation, and patient-reported quality of life did not differ in CABG guided by functional testing from those guided by traditional angiography.The survey revealed that in half of the surgical and cardiology units functional assessment is performed in CABG patients; there is a general perception that functional testing has improved patient care and its use would clarify the role of moderate coronary lesions that often need multidisciplinary rediscussions; moderate stenosis are felt to be clinically relevant; and anatomical considerations need to be taken into account together with functional assessment.

Conclusions

At present, the evidence to support the routine use of functional testing in intermediate lesions for planning CABG is currently insufficient. The pooled data currently available do not show an increased risk in mortality, myocardial injury, and stroke in the FFR/iFR-guided group. Further trials with highly selected populations are needed to clarify the best strategy.

Systematic Review Registration

ClinicalTrials.gov, identifier (CRD42023414604).

High-precision measurement of the W boson mass with the CDF II detector

The mass of the W boson, a mediator of the weak force between elementary particles, is tightly constrained by the symmetries of the standard model of particle physics. The Higgs boson was the last missing component of the model. After observation of the Higgs boson, a measurement of the W boson mass provides a stringent test of the model. We measure the W boson mass, M_W, using data corresponding to 8.8 inverse femtobarns of integrated luminosity collected in proton-antiproton collisions at a 1.96 tera-electron volt center-of-mass energy with the CDF II detector at the Fermilab Tevatron collider. A sample of approximately 4 million W boson candidates is used to obtain [Formula: see text], the precision of which exceeds that of all previous measurements combined (stat, statistical uncertainty; syst, systematic uncertainty; MeV, mega-electron volts; c, speed of light in a vacuum). This measurement is in significant tension with the standard model expectation.

Different abscisic acid-deficient mutants show unique morphological and hydraulic responses to high air humidity

High relative humidity (RH) perturbs plant growth, stomatal functioning and abscisic acid (ABA) homeostasis, but the role of ABA in this physiological regulation is equivocal. To determine the role(s) of ABA in plant responses to high RH, wild-type (WT) tomato and barley plants and their respective ABA-deficient mutants flacca and Az34 (which are mutated in the same locus of the ABA biosynthesis pathway) were grown in contrasting RHs (60% and 90%) to measure biomass partitioning, stomatal traits and water relations. Surprisingly, growth RH did not affect foliar ABA levels in either species. While Az34 showed similar stomatal size and density as WT plants, flacca had larger and more abundant stomata. High RH increased stomatal size in tomato, but decreased it in barley, and decreased stomatal density in tomato, but not in barley. Altered stomatal responses in ABA-deficient plants to high RH had little effect on tomato photosynthesis, but Az34 barley showed lower photosynthesis. ABA deficiency decreased relative shoot growth rate (RGR_SHOOT ) in both species, yet this was counteracted by high RH increasing leaf water status in tomato, but not in barley. High RH increased RGR_SHOOT in flacca, but not in WT tomatoes, while having no effect on RGR_SHOOT in barley, but affecting barley net assimilation rate, leaf area ratio (LAR) and specific leaf area in an ABA-dependent manner. ABA-RH interaction affected leaf development in tomato only. Thus, different crop species show variable responses to both high RH and ABA deficiency, making it difficult to generalise on the role of ABA in growth regulation at contrasting RHs.

Blue Light Improves Stomatal Function and Dark-Induced Closure of Rose Leaves (Rosa x hybrida) Developed at High Air Humidity

Plants developed under constant high (>85%) relative air humidity (RH) have larger stomata that are unable to close completely in response to closing stimuli. Roses (Rosa x hybrida) developed in high RH have previously been shown to have high water loss during leaf dehydration and reduced dark-induced closure resulting in a shorter postharvest life. In this study, the effect of B-light on stomatal function under high RH conditions was investigated. The ability of rose leaves developed under continuous high (90%) or moderate (60%) RH to close their stomata in response to darkness and leaf dehydration assay was studied. Moreover, the level and regulation of ABA in light and darkness in relation to B-light was measured. Our results show that increased B-light proportion improved stomatal function and dark-induced stomatal closure under high RH conditions and that was associated with increased [ABA] in general and a dynamic ABA peak during darkness. Furthermore, increased B-light during the day was associated with the presence of high β-glucosidase activity during night. This indicates that B-light is important as a signal to activate the β-glucosidase enzyme and release ABA during night. Altogether, the improved stomatal function and reduced transpiration in combination with increased [ABA] indicate that preharvest B-light plays an important role in governing stomatal functionality and ABA homeostasis under high RH and can be a useful method to improve postharvest water balance of roses.

Development of methods for the preparation of radiopure 82Se sources for the SuperNEMO neutrinoless double-beta decay experiment

A radiochemical method for producing 82Se sources with an ultra-low level of contamination of natural radionuclides (40K, decay products of 232Th and 238U) has been developed based on cation-exchange chromatographic purification with reverse removal of impurities. It includes chromatographic separation (purification), reduction, conditioning (which includes decantation, centrifugation, washing, grinding, and drying), and 82Se foil production. The conditioning stage, during which highly dispersed elemental selenium is obtained by the reduction of purified selenious acid (H2SeO3) with sulfur dioxide (SO2) represents the crucial step in the preparation of radiopure 82Se samples. The natural selenium (600 g) was first produced in this procedure in order to refine the method. The technique developed was then used to produce 2.5 kg of radiopure enriched selenium (82Se). The produced 82Se samples were wrapped in polyethylene (12 μm thick) and radionuclides present in the sample were analyzed with the BiPo-3 detector. The radiopurity of the plastic materials (chromatographic column material and polypropylene chemical vessels), which were used at all stages, was determined by instrumental neutron activation analysis. The radiopurity of the 82Se foils was checked by measurements with the BiPo-3 spectrometer, which confirmed the high purity of the final product. The measured contamination level for 208Tl was 8–54 μBq/kg, and for 214Bi the detection limit of 600 μBq/kg has been reached.

Elevated air humidity increases UV mediated leaf and DNA damage in pea (Pisum sativum) due to reduced flavonoid content and antioxidant power

Growth in high relative air humidity (RH, >85%) affects plant morphology and causes diminished response to stomatal closing signals. Many greenhouses are prone to high RH conditions, which may negatively affect production and post-harvest quality. UV radiation induces stomatal closure in several species, and facilitates disease control. We hypothesised that UV exposure may trigger stomatal closure in pea plants (Pisum sativum) grown in high RH, thereby restoring stomatal function. The effects of UV exposure were tested on plants grown in moderate (60%) or high (90%) RH. UV exposure occurred at night, according to a disease control protocol. Lower stomatal conductance rates were found in UV-exposed plants, though UV exposure did not improve the rate of response to closing stimuli or desiccation tolerance. UV-exposed plants showed leaf curling, chlorosis, necrosis, and DNA damage measured by the presence of cyclobutane pyrimidine dimers (CPD), all of which were significantly greater in high RH plants. These plants also had lower total flavonoid content than moderate RH plants, and UV-exposed plants had less than controls. Plants exposed to UV had a higher content of cuticular layer uronic compounds than control plants. However, high RH plants had a higher relative amount of cuticular waxes, but decreased proteins and uronic compounds. Plants grown in high RH had reduced foliar antioxidant power compared to moderate RH. These results indicate that high RH plants were more susceptible to UV-induced damage than moderate RH plants due to reduced flavonoid content and oxidative stress defence.

Search for the Exotic Meson X(5568) with the Collider Detector at Fermilab

A search for the exotic meson X(5568) decaying into the B_{s}^{0}π^{±} final state is performed using data corresponding to 9.6  fb^{-1} from pp[over ¯] collisions at sqrt[s]=1960  GeV recorded by the Collider Detector at Fermilab. No evidence for this state is found and an upper limit of 6.7% at the 95% confidence level is set on the fraction of B_{s}^{0} produced through the X(5568)→B_{s}^{0}π^{±} process.

Combined Forward-Backward Asymmetry Measurements in Top-Antitop Quark Production at the Tevatron

The CDF and D0 experiments at the Fermilab Tevatron have measured the asymmetry between yields of forward- and backward-produced top and antitop quarks based on their rapidity difference and the asymmetry between their decay leptons. These measurements use the full data sets collected in proton-antiproton collisions at a center-of-mass energy of sqrt[s]=1.96  TeV. We report the results of combinations of the inclusive asymmetries and their differential dependencies on relevant kinematic quantities. The combined inclusive asymmetry is A_{FB}^{tt[over ¯]}=0.128±0.025. The combined inclusive and differential asymmetries are consistent with recent standard model predictions.

Search for Neutrinoless Quadruple-β Decay of ^{150}Nd with the NEMO-3 Detector

We report the results of a first experimental search for lepton number violation by four units in the neutrinoless quadruple-β decay of ^{150}Nd using a total exposure of 0.19 kg yr recorded with the NEMO-3 detector at the Modane Underground Laboratory. We find no evidence of this decay and set lower limits on the half-life in the range T_{1/2}>(1.1-3.2)×10^{21}  yr at the 90% C.L., depending on the model used for the kinematic distributions of the emitted electrons.

Daily changes in VPD during leaf development in high air humidity increase the stomatal responsiveness to darkness and dry air

Previous studies have shown that plants developed under high relative air humidity (RH>85%) develop malfunctioning stomata and therefor have increased transpiration and reduced desiccation tolerance when transferred to lower RH conditions and darkness. In this study, plants developed at high RH were exposed to daily VPD fluctuations created by changes in temperature and/or RH to evaluate the potential improvements in stomatal functioning. Daily periods with an 11°C temperature increase and consequently a VPD increase (vpd: 0.36-2.37KPa) reduced the stomatal apertures and improved the stomatal functionality and desiccation tolerance of the rosette plant Arabidopsis thaliana. A similar experiment was performed with only a 4°C temperature increase and/or a RH decrease on tomato. The results showed that a daily change in VPD (vpd: 0.36-1.43KPa) also resulted in improved stomatal responsiveness and decreased water usage during growth. In tomato, the most effective treatment to increase the stomatal responsiveness to darkness as a signal for closure was daily changes in RH without a temperature increase.

The BiPo-3 detector

The BiPo-3 detector is a low radioactive detector dedicated to measuring ultra-low natural contaminations of ²⁰⁸Tl and ²¹⁴Bi in thin materials, initially developed to measure the radiopurity of the double β decay source foils of the SuperNEMO experiment at the μBq/kg level. The BiPo-3 technique consists in installing the foil of interest between two thin ultra-radiopure scintillators coupled to low radioactive photomultipliers. The design and performances of the detector are presented. In this paper, the final results of the ²⁰⁸Tl and ²¹⁴Bi activity measurements of the first enriched ⁸²Se foils are reported for the first time, showing the capability of the detector to reach sensitivities in the range of some μBq/kg.

Thermoperiodic Control of Floral Induction Involves Modulation of the Diurnal FLOWERING LOCUS T Expression Pattern

Thermoperiodism is defined as the ability to discriminate between day temperature (DT) and night temperature (NT). Our aim was to shed light on the mechanistic basis of thermoperiodic floral induction with acceleration under lower DT than NT compared with other DT-NT combinations at the same average daily temperature (ADT), a response exploited in temperate area greenhouses. Arabidopsis thaliana floral pathway mutants and a lhy circadian clock mutant as well as the expression of floral integrators and LHY (LATE ELONGATED HYPOCOTYL) were studied under different DT-NT combinations, all at the same ADT. We show that acceleration of floral induction under lower DT than NT is linked to increased FT expression early during the day and generally increased LFY expression preceding visible flower buds, compared with higher DT than NT or equal DT and NT. Consistent with FLOWERING LOCUS T (FT) action through LEAFY (LFY), time to floral transition in ft-1 and lfy-1 was similar under all treatments, in contrast to the situation for soc1-1, which behaved like the wild type (WT). The lhy-21 mutants did not discriminate between opposite DT-NT combinations, whereas LHY expression in the WT differed in these temperature regimes. This might suggest that LHY plays a role in thermoperiodic control of floral induction. We conclude that thermoperiodic control of floral transition is associated with modulation of the diurnal expression patterns of FT, with timing of temperature alteration being important rather than ADT.

Management of diabetes patients during the year prior to initiation of dialysis in France

AIM

This study looked at the management of diabetes patients during the year prior to the initiation of dialysis.

METHODS

For this observational study, data were extracted from the National Health Insurance database for general-scheme beneficiaries (77% of the French population). Diabetes patients were identified by at least three reimbursements for antidiabetic drugs in 2012, while the initiation of dialysis was identified by specific refunds in 2013.

RESULTS

Of the 6412 patients initiating dialysis, 37% (n=2378) had diabetes (men: 61%, median age: 71 years, haemodialysis: 92%). Six months prior to dialysis, 68% had filled at least one prescription for insulin, 38% for other antidiabetics (25% glinides, 8% sulphonylureas, 8% metformin, 6% DPP-4 inhibitors), 69% for three or more classes of antihypertensive drugs and 55% for erythropoiesis-stimulating agents. Within 12 months to 1 month of dialysis, 81% were hospitalized, 28% with a main diagnosis of kidney disease. No nephrologist referral or hospitalization was identified at 6-0 months before dialysis in 6% of patients or in 24% at 12-7 months. One in five patients with diabetes consulted a private endocrinologist within 6 months of dialysis. An arteriovenous fistula was created 1 month before haemodialysis in 43% of patients.

CONCLUSION

The quality of preparation for dialysis was variable despite frequent hospitalizations. These data illustrate the need to mobilize patients with diabetes, and for healthcare professionals to more effectively anticipate and coordinate dialysis.

Tevatron Combination of Single-Top-Quark Cross Sections and Determination of the Magnitude of the Cabibbo-Kobayashi-Maskawa Matrix Element V_{tb}

We present the final combination of CDF and D0 measurements of cross sections for single-top-quark production in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7 fb^{-1} per experiment. The t-channel cross section is measured to be σ_{t}=2.25_{-0.31}^{+0.29} pb. We also present the combinations of the two-dimensional measurements of the s- vs t-channel cross section. In addition, we give the combination of the s+t channel cross section measurement resulting in σ_{s+t}=3.30_{-0.40}^{+0.52} pb, without assuming the standard model value for the ratio σ_{s}/σ_{t}. The resulting value of the magnitude of the top-to-bottom quark coupling is |V_{tb}|=1.02_{-0.05}^{+0.06}, corresponding to |V_{tb}|>0.92 at the 95% C.L.

Search for Resonances Decaying to Top and Bottom Quarks with the CDF Experiment

We report on a search for charged massive resonances decaying to top (t) and bottom (b) quarks in the full data set of proton-antiproton collisions at a center-of-mass energy of √[s]=1.96  TeV collected by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.5  fb(-1). No significant excess above the standard model background prediction is observed. We set 95% Bayesian credibility mass-dependent upper limits on the heavy charged-particle production cross section times branching ratio to tb. Using a standard model extension with a W'→tb and left-right-symmetric couplings as a benchmark model, we constrain the W' mass and couplings in the 300-900  GeV/c(2) range. The limits presented here are the most stringent for a charged resonance with mass in the range 300-600  GeV/c(2) decaying to top and bottom quarks.

Elevated air movement enhances stomatal sensitivity to abscisic acid in leaves developed at high relative air humidity

High relative air humidity (RH ≥ 85%) during growth leads to stomata malfunctioning, resulting in water stress when plants are transferred to conditions of high evaporative demand. In this study, we hypothesized that an elevated air movement (MOV) 24 h per day, during the whole period of leaf development would increase abscisic acid concentration ([ABA]) enhancing stomatal functioning. Pot rose 'Toril' was grown at moderate (61%) or high (92%) RH combined with a continuous low (0.08 m s(-1)) or high (0.92 m s(-1)) MOV. High MOV reduced stomatal pore length and aperture in plants developed at high RH. Moreover, stomatal function improved when high MOV-treated plants were subjected to leaflet desiccation and ABA feeding. Endogenous concentration of ABA and its metabolites in the leaves was reduced by 35% in high RH, but contrary to our hypothesis this concentration was not significantly affected by high MOV. Interestingly, in detached leaflets grown at high RH, high MOV increased stomatal sensitivity to ABA since the amount of exogenous ABA required to decrease the transpiration rate was significantly reduced. This is the first study to show that high MOV increases stomatal functionality in leaves developed at high RH by reducing the stomatal pore length and aperture and enhancing stomatal sensitivity to ABA rather than increasing leaf [ABA].

Tevatron constraints on models of the Higgs boson with exotic spin and parity using decays to bottom-antibottom quark pairs

Combined constraints from the CDF and D0 Collaborations on models of the Higgs boson with exotic spin J and parity P are presented and compared with results obtained assuming the standard model value JP=0+. Both collaborations analyzed approximately 10  fb(-) of proton-antiproton collisions with a center-of-mass energy of 1.96 TeV collected at the Fermilab Tevatron. Two models predicting exotic Higgs bosons with JP=0- and JP=2+ are tested. The kinematic properties of exotic Higgs boson production in association with a vector boson differ from those predicted for the standard model Higgs boson. Upper limits at the 95% credibility level on the production rates of the exotic Higgs bosons, expressed as fractions of the standard model Higgs boson production rate, are set at 0.36 for both the JP=0- hypothesis and the JP=2+ hypothesis. If the production rate times the branching ratio to a bottom-antibottom pair is the same as that predicted for the standard model Higgs boson, then the exotic bosons are excluded with significances of 5.0 standard deviations and 4.9 standard deviations for the JP=0- and JP=2+ hypotheses, respectively.

Constraints on models of the Higgs boson with exotic spin and parity using decays to bottom-antibottom quarks in the full CDF data set

A search for particles with the same mass and couplings as those of the standard model Higgs boson but different spin and parity quantum numbers is presented. We test two specific alternative Higgs boson hypotheses: a pseudoscalar Higgs boson with spin-parity J^{P}=0^{-} and a gravitonlike Higgs boson with J^{P}=2^{+}, assuming for both a mass of 125  GeV/c^{2}. We search for these exotic states produced in association with a vector boson and decaying into a bottom-antibottom quark pair. The vector boson is reconstructed through its decay into an electron or muon pair, or an electron or muon and a neutrino, or it is inferred from an imbalance in total transverse momentum. We use expected kinematic differences between events containing exotic Higgs bosons and those containing standard model Higgs bosons. The data were collected by the CDF experiment at the Tevatron proton-antiproton collider, operating at a center-of-mass energy of sqrt[s]=1.96  TeV, and correspond to an integrated luminosity of 9.45  fb^{-1}. We exclude deviations from the predictions of the standard model with a Higgs boson of mass 125  GeV/c^{2} at the level of 5 standard deviations, assuming signal strengths for exotic boson production equal to the prediction for the standard model Higgs boson, and set upper limits of approximately 30% relative to the standard model rate on the possible rate of production of each exotic state.

Ethylene is involved in high air humidity promoted stomatal opening of tomato (Lycopersicon esculentum) leaves

High relative air humidity (RH) promotes stomatal opening in tomato leaves. This study examined the role of the plant hormones abscisic acid (ABA) and ethylene in high RH induced stomatal opening. Plants were grown in high (90%) and moderate (60%) RH or transferred from moderate to high RH. ABA levels were only slightly, but significantly decreased during darkness by increasing RH. However, a significantly higher ethylene evolution was found in high RH compared with moderate RH. Ethephon increased conductance and stomatal aperture in moderate RH. Treatment with amino-ethoxyvinylglycine (AVG) suppressed stomatal opening when plants were transferred from moderate to high RH. Similarly, blocking the ethylene receptor or using an ethylene-insensitive mutant (NR) reduced the response to high RH. These results demonstrate that both ethylene production and sensitivity play a role in high RH-induced stomatal opening in tomato leaves. The increased conductance found when plants were transferred to high RH could be counteracted by exogenous ABA spray. The ABA deficient mutant 'Flacca' produced high levels of ethylene irrespective of the RH and the difference in water loss and conductance between high and moderate grown 'Flacca' plants was attenuated compared with WT. The results indicate that both ABA and ethylene play a role in air humidity control of stomatal movement in tomato.

Measurement of the single top quark production cross section and |Vtb| in events with one charged lepton, large missing transverse energy, and jets at CDF

We report a measurement of single top quark production in proton-antiproton collisions at a center-of-mass energy of sqrt[s]=1.96  TeV using a data set corresponding to 7.5  fb(-1) of integrated luminosity collected by the Collider Detector at Fermilab. We select events consistent with the single top quark decay process t→Wb→ℓνb by requiring the presence of an electron or muon, a large imbalance of transverse momentum indicating the presence of a neutrino, and two or three jets including at least one originating from a bottom quark. An artificial neural network is used to discriminate the signal from backgrounds. We measure a single top quark production cross section of 3.04(-0.53)(+0.57)  pb and set a lower limit on the magnitude of the coupling between the top quark and bottom quark |Vtb|>0.78 at the 95% credibility level.

Measurements of direct CP-violating asymmetries in charmless decays of bottom baryons

We report final measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using the complete √s=1.96  TeV proton-antiproton collisions data set, corresponding to 9.3  fb⁻¹ of integrated luminosity, we measure A(Λ(b)⁰→pπ⁻)=+0.06±0.07(stat)±0.03(syst) and A(Λ(b)⁰→pK⁻)=-0.10±0.08(stat)±0.04(syst), compatible with no asymmetry. In addition we measure the CP-violating asymmetries in B(s)⁰→K⁻π⁺ and B⁰→K⁺π⁻ decays to be A(B(s)⁰→K⁻π⁺)=+0.22±0.07(stat)±0.02(syst) and A(B⁰→K⁺π⁻)=-0.083±0.013(stat)±0.004(syst), respectively, which are significantly different from zero and consistent with current world averages.

Suppression of Cucumber Powdery Mildew by Supplemental UV-B Radiation in Greenhouses Can be Augmented or Reduced by Background Radiation Quality

This study demonstrates that the spectral quality of radiation sources applied with ultraviolet-B (UV-B; background radiation) affects the suppression of cucumber powdery mildew (Podosphaera xanthii) by UV-B. Suppression provided by daily UV-B exposure of 1 W/m² for 10 min was greatest in the presence of red light or by a complete lack of background light, and powdery mildew suppression was least in the presence of ultraviolet-A (UV-A) or blue radiation compared with plants exposed only to 16 h of daily natural light supplemented with high-pressure sodium lamps that supply broad-spectrum radiation with peaks in the yellow-orange region. Exposure of powdery mildew-inoculated plants to supplemental red light without UV-B, beginning at the end of the daylight period, also reduced disease severity; however, supplemental blue light applied in the same fashion had no effect. Daily application of UV-B at 1 W/m² beginning on the day of inoculation significantly reduced the severity of powdery mildew to 15% compared with 100% severity on control plants. Maximum suppression of powdery mildew was observed following 15 min of exposure to UV-B (1.1% severity compared with 100% severity on control plants) but exposure time had to be limited to 5 to 10 min to reduce phytotoxicity. There was no additional disease suppression when plants were exposed to UV-B beginning 2 days prior to inoculation compared with plants exposed to UV-B beginning on the day of inoculation. UV-B inhibited germination, infection, colony expansion, and sporulation of P. xanthii. The results suggest that efficacy of UV-B treatments, alone or in combination with red light, against P. xanthii can be enhanced by exposure of inoculated plants to these wavelengths of radiation during the night, thereby circumventing the counteracting effects of blue light and UV-A radiation. The effect of UV-B on powdery mildew seemed to be directly upon the pathogen, rather than induced resistance of the host. Night exposure of plants to 5 to 10 min of UV-B at 1 W/m² and inexpensive, spectral-specific, light-emitting diodes may provide additional tools to suppress powdery mildews of diverse greenhouse crops.

Measurement of the inclusive leptonic asymmetry in top-quark pairs that decay to two charged leptons at CDF

We measure the inclusive forward-backward asymmetry of the charged-lepton pseudorapidities from top-quark pairs produced in proton-antiproton collisions and decaying to final states that contain two charged leptons (electrons or muons). The data are collected with the Collider Detector at Fermilab and correspond to an integrated luminosity of 9.1 fb(-1). We measure the leptonic forward-backward asymmetry, A(FB)(ℓ), to be 0.072 ± 0.060 and the leptonic pair forward-backward asymmetry, A(FB)(ℓℓ), to be 0.076 ± 0.082. The measured values can be compared with the standard model predictions of A(FB)(ℓ) = 0.038 ± 0.003 and A(FB)(ℓℓ) = 0.048 ± 0.004, respectively. Additionally, we combine the A(FB)(ℓ) result with a previous determination from a final state with a single lepton and hadronic jets and obtain A(FB)(ℓ) = 0.090(-0.026)(+0.028).

Evidence for s-channel single-top-quark production in events with one charged lepton and two jets at CDF

We report evidence for s-channel single-top-quark production in proton-antiproton collisions at center-of-mass energy sqrt[s] = 1.96 TeV using a data set that corresponds to an integrated luminosity of 9.4 fb(-1) collected by the Collider Detector at Fermilab. We select events consistent with the s-channel process including two jets and one leptonically decaying W boson. The observed significance is 3.8 standard deviations with respect to the background-only prediction. Assuming a top-quark mass of 172.5 GeV/c(2), we measure the s-channel cross section to be 1.41(-0.42)(+0.44) pb.

Search for s-channel single-top-quark production in events with missing energy plus jets in pp collisions at sqrt[s] = 1.96 TeV

The first search for single-top-quark production from the exchange of an s-channel virtual W boson using events with an imbalance in the total transverse energy, b-tagged jets, and no identified leptons is presented. Assuming the electroweak production of top quarks of mass 172.5 GeV/c(2) in the s channel, a cross section of 1.12(-0.57)(+0.61) (stat+syst) pb with a significance of 1.9 standard deviations is measured. This measurement is combined with the result obtained from events with an imbalance in total transverse momentum, b-tagged jets, and exactly one identified lepton, yielding a cross section of 1.36(-0.32)(+0.37) (stat+syst) pb, with a significance of 4.2 standard deviations.

Observation of s-channel production of single top quarks at the Tevatron

We report the first observation of single-top-quark production in the s channel through the combination of the CDF and D0 measurements of the cross section in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7 fb(-1) per experiment. The measured cross section is σ(s) = 1.29(-0.24)(+0.26) pb. The probability of observing a statistical fluctuation of the background to a cross section of the observed size or larger is 1.8 × 10(-10), corresponding to a significance of 6.3 standard deviations for the presence of an s-channel contribution to the production of single-top quarks.

Measurement of B(t→Wb)/B(t→Wq) in top-quark-pair decays using dilepton events and the full CDF Run II data set

We present a measurement of the ratio of the top-quark branching fractions R=B(t→Wb)/B(t→Wq), where q represents any quark flavor, in events with two charged leptons, imbalance in total transverse energy, and at least two jets. The measurement uses proton-antiproton collision data at center-of-mass energy 1.96 TeV, corresponding to an integrated luminosity of 8.7  fb^{-1} collected with the Collider Detector at Fermilab during Run II of the Tevatron. We measure R to be 0.87±0.07, and extract the magnitude of the top-bottom quark coupling to be |V_{tb}|=0.93±0.04, assuming three generations of quarks. Under these assumptions, a lower limit of |V_{tb}|>0.85(0.87) at 95% (90%) credibility level is set.

First search for exotic Z Boson decays into photons and neutral pions in hadron collisions

A search for forbidden and exotic Z boson decays in the diphoton mass spectrum is presented for the first time in hadron collisions, based on data corresponding to 10.0 fb(-1) of integrated luminosity from proton-antiproton collisions at √s = 1.96 TeV collected by the CDF experiment. No evidence of signal is observed, and 95% credibility level Bayesian upper limits are set on the branching ratios of decays of the Z boson to a photon and neutral pion (which is detected as a photon), a pair of photons, and a pair of neutral pions. The observed branching ratio limits are 2.01 × 10(-5) for Z → π(0)γ, 1.46 × 10(-5) for Z → γγ, and 1.52 × 10(-5) for Z → π(0)π(0). The Z → π(0)γ and Z → γγ limits improve the most stringent results from other experiments by factors of 2.6 and 3.6, respectively. The Z → π(0)π(0) branching ratio limit is the first experimental result on this decay.

ABA induces H2O2 production in guard cells, but does not close the stomata on Vicia faba leaves developed at high air humidity

Plants developed under constant high (> 85%) relative air humidity (RH) have larger stomata that are unable to close completely. One of the hypotheses for the less responsive stomata is that the plants have reduced sensitivity to abscisic acid (ABA). Both ABA and darkness are signals for stomatal closure and induce the production of the secondary messenger hydrogen peroxide (H2O2). In this study, the ability of Vicia faba plants developed in moderate or high RH to close the stomata in response to darkness, ABA and H2O2 was investigated. Moreover, the ability of the plants to produce H2O2 when treated with ABA or transferred to darkness was also assessed. Our results show that the ABA concentration in moderate RH is not increased during darkness even though the stomata are closing. This indicates that stomatal closure in V. faba during darkness is independent of ABA production. ABA induced both H2O2 production and stomatal closure in stomata formed at moderate RH. H2O2 production, as a result of treatment with ABA, was also observed in stomata formed at high RH, though the closing response was considerably smaller as compared with moderate RH. In either RH, leaf ABA concentration was not affected by darkness. Similarly to ABA treatment, darkness elicited both H2O2 production and stomatal closure following plant cultivation at moderate RH. Contrary to this, neither H2O2 production nor stomatal closure took place when stomata were formed at high RH. These results suggest that the reduced stomatal response in plants developed in continuous high RH is caused by one or more factors downstream of H2O2 in the signaling pathway toward stomatal closure.

Observation of D⁰-D¯⁰ mixing using the CDF II detector

We measure the time dependence of the ratio of decay rates for D0→K(+)π(-) to the Cabibbo-favored decay D(0)→K(-)π(+). The charge conjugate decays are included. A signal of 3.3×10(4) D(*+)→π(+)D(0), D(0)→K(+)π(-) decays is obtained with D0 proper decay times between 0.75 and 10 mean D0 lifetimes. The data were recorded with the CDF II detector at the Fermilab Tevatron and correspond to an integrated luminosity of 9.6  fb(-1) for pp¯ collisions at √s=1.96  TeV. Assuming CP conservation, we search for D0-D¯0 mixing and measure the mixing parameters to be R(D)=(3.51±0.35)×10(-3), y'=(4.3±4.3)×10(-3), and x'2=(0.08±0.18)×10(-3). We report Bayesian probability intervals in the x'2-y' plane and find that the significance of excluding the no-mixing hypothesis is equivalent to 6.1 Gaussian standard deviations, providing the second observation of D0-D¯0 mixing from a single experiment.

Direct measurement of the total decay width of the top quark

We present a measurement of the total decay width of the top quark using events with top-antitop quark pair candidates reconstructed in the final state with one charged lepton and four or more hadronic jets. We use the full Tevatron run II data set of sqrt[s]=1.96  TeV proton-antiproton collisions recorded by the CDF II detector. The top quark mass and the mass of the hadronically decaying W boson are reconstructed for each event and compared with distributions derived from simulated signal and background samples to extract the top quark width (Γtop) and the energy scale of the calorimeter jets with in situ calibration. For a top quark mass Mtop=172.5  GeV/c2, we find 1.10<Γtop<4.05  GeV at 68% confidence level, which is in agreement with the standard model expectation of 1.3 GeV and is the most precise direct measurement of the top quark width to date.