The tribe Spermacoceae (Rubiaceae) in the State of Ceará, northeastern Brazil

Tribe Spermacoceae comprises more than 1000 species and about 80 genera, being the largest lineage of herbaceous plants within Rubiaceae. Historically, it is marked by taxonomic complexes. This study aims to investígate the diversity and geographical distribution o f the tribe Spermacoceae in Ceará, in the Northeast región of Brazil. This State covers an area o f 150,000 km2 within the Caatinga domain and is divided into 11 phytoecological units, where the Crystalline Caatinga predominates. Specimens collected from 1990 to 2023, and collections from the EAC, HCDAL, HUEFS, HUVA, and PEUFR herbaria were analysed. The tribe is represented in Ceará by 31 species, of which Borreria savannicola and Mitracarpus fernandesii are endemic to the State, and seven genera, with Borreria being the most diverse (13 spp.), followed by Mitracarpus (six spp.), Hexasepalum (four spp.), Richardia and Spermacoce (three spp. each), andEmmeorhiza and Staelia (one sp. each). In total, 605 collections were verified. Morphological characteristics of fruit, seed, pollen, and intemal indumentum o f the corolla were diagnostic for taxonomic delimitation, with new species having been described for Science in recent years (B. apodiensis, B. savannicola, and H. nordestinum). Borreria scabiosoides has the broadest geographic range, while B. cupularis, B. savannicola, H. nordestinum, and M. polygonifolius are the most restricted species. The northwest región of Ceará is the most diverse (with 22 to 26 species), followed by the south (with 17 to 21 species). The same pattem was verified for the distribution o f records, with the northwest región having the highest numbers (232 to 289 records), whereas the south presents fewer records (59 to 116). Therefore, despite the northwest región having the highest number of species, the greatest diversity relative to the number o f records is found in the Southern región of Ceará. Acknowledgements: FUNCAP (Process BP5-0197-00136.01.00/22); UVA

Small structure, big significance: seed morphology of South American species of M itracarpus (Rubiaceae - Spermacoceae)

Mitracarpus Zuce, ex Schult. & Schult.f. comprises about 50 species distributed mainly throughout tropical and subtropical regions of the New World, from Southern United States to central Argentina. Considering the importance of micromorphological characters for the taxonomy of Spermacoceae s.s. (Rubiaceae), the present study aimed to analyse the taxonomic significance of seed micromorphology in Mitracarpus species from South America. The seeds of 29 species were analysed through light microscopy and scanning electrón microscopy (SEM). For SEM analyses the seeds were mounted on stubs, air dried, covered with gold-palladium. The analyses revealed four pattems and eight subtypes in Mitracarpus, based mainly on the shape of the ventral groove and exotesta features: (1) X-shaped groove: 1.1. reticulate-areolate exotesta, without cruciform depression (M eritricoides, M. parvulus, M. longicalyx, M. nitidus)', 1.2. reticulate-areolate exotesta, with cruciform depression (M. albomarginatus, M. bacigalupoae, M. femandesii); 1.3. reticulate-foveate exotesta, without cruciform depression (M. brasiliensis, M. federalensis, M. hirtus, M. microspermus, M. nitidus, M. polygonifolius); 1.4. papillate exotesta, without cruciform depression (M. pusillus, M. recurvatus, M. steyermarkii); 1.5. reticulate-foveate exotesta, with cruciform depression (M. anthospermoides,M. carajasensis,M. baturitensis,M. bicrucis,M. frigidus); (2) Inverted-Y-shaped groove, reticulate-foveate exotesta, without cruciform depression (M. eichleri, M. salzmannianus, M. semirianus); (3) Rectangularquadrangular-shaped groove, reticulate-areolate exotesta, without cruciform depression (M hasslerianus, M. Ihotzkyanus, M. megapotamicus, M. rigidifolius); (4) Oblong-shaped groove, reticulate-foveate exotesta, without cruciform depression (M. diversifolius). The data obtained here have shown the systematic importance o f seed characteristics in Mitracarpus, as well their valué to indicate affinities among species. It is expected that this study regarding the seed characters in Mitracarpus can provide a potential source o f apomorphies to discem the clades in future molecular phylogenetic analyses. Acknowledgements: FUNCAP (Process BP5-0197-00136.01.00/22); Royal Botanic Gardens, Kew; KLARF (Kew Latín American Research Fellowships Programme); CONICET

Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30

Measurement of χ c1 and χ c2 production with s√ = 7 TeV pp collisions at ATLAS

The prompt and non-prompt production cross-sections for the χ c1 and χ c2 charmonium states are measured in pp collisions at s√ = 7 TeV with the ATLAS detector at the LHC using 4.5 fb−1 of integrated luminosity. The χ c states are reconstructed through the radiative decay χ c → J/ψγ (with J/ψ → μ + μ −) where photons are reconstructed from γ → e + e − conversions. The production rate of the χ c2 state relative to the χ c1 state is measured for prompt and non-prompt χ c as a function of J/ψ transverse momentum. The prompt χ c cross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χ c decays. The fractions of χ c1 and χ c2 produced in b-hadron decays are also measured

Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at s√=8 TeV with ATLAS

Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of s√=8 TeV. The analysis is performed in the H → γγ decay channel using 20.3 fb−1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp → H → γγ fiducial cross section is measured to be 43.2 ±9.4(stat.) − 2.9 + 3.2 (syst.) ±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations

Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector

Results of a search for H → τ τ decays are presented, based on the full set of proton-proton collision data recorded by the ATLAS experiment at the LHC during 2011 and 2012. The data correspond to integrated luminosities of 4.5 fb−1 and 20.3 fb−1 at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV respectively. All combinations of leptonic (τ → `νν¯ with ` = e, µ) and hadronic (τ → hadrons ν) tau decays are considered. An excess of events over the expected background from other Standard Model processes is found with an observed (expected) significance of 4.5 (3.4) standard deviations. This excess provides evidence for the direct coupling of the recently discovered Higgs boson to fermions. The measured signal strength, normalised to the Standard Model expectation, of µ = 1.43 +0.43 −0.37 is consistent with the predicted Yukawa coupling strength in the Standard Model

Measurement of the top pair production cross section in 8 TeV proton-proton collisions using kinematic information in the lepton plus jets final state with ATLAS

A measurement is presented of the $t\bar{t}$ inclusive production cross-section in $pp$ collisions at a center-of-mass energy of $\sqrt{s}=8$ TeV using data collected by the ATLAS detector at the CERN Large Hadron Collider. The measurement was performed in the lepton+jets final state using a data set corresponding to an integrated luminosity of 20.3 fb$^{-1}$. The cross-section was obtained using a likelihood discriminant fit and $b$-jet identification was used to improve the signal-to-background ratio. The inclusive $t\bar{t}$ production cross-section was measured to be $260\pm 1{\textrm{(stat.)}} ^{+22}_{-23} {\textrm{(syst.)}}\pm 8{\textrm{(lumi.)}}\pm 4{\mathrm{(beam)}}$ pb assuming a top-quark mass of 172.5 GeV, in good agreement with the theoretical prediction of $253^{+13}_{-15}$ pb. The $t\bar{t}\to (e,\mu)+{\mathrm{jets}}$ production cross-section in the fiducial region determined by the detector acceptance is also reported.Comment: Published version, 19 pages plus author list (35 pages total), 3 figures, 2 tables, all figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2013-06

Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector

The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry

Search for squarks and gluinos with the ATLAS detector in final states with jets and missing transverse momentum using √s=8 TeV proton-proton collision data

A search for squarks and gluinos in final states containing high-p T jets, missing transverse momentum and no electrons or muons is presented. The data were recorded in 2012 by the ATLAS experiment in s√=8 TeV proton-proton collisions at the Large Hadron Collider, with a total integrated luminosity of 20.3 fb−1. Results are interpreted in a variety of simplified and specific supersymmetry-breaking models assuming that R-parity is conserved and that the lightest neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 1330 GeV for a simplified model incorporating only a gluino and the lightest neutralino. For a simplified model involving the strong production of first- and second-generation squarks, squark masses below 850 GeV (440 GeV) are excluded for a massless lightest neutralino, assuming mass degenerate (single light-flavour) squarks. In mSUGRA/CMSSM models with tan β = 30, A 0 = −2m 0 and μ > 0, squarks and gluinos of equal mass are excluded for masses below 1700 GeV. Additional limits are set for non-universal Higgs mass models with gaugino mediation and for simplified models involving the pair production of gluinos, each decaying to a top squark and a top quark, with the top squark decaying to a charm quark and a neutralino. These limits extend the region of supersymmetric parameter space excluded by previous searches with the ATLAS detector