497 research outputs found

    Prospective Follow-up of Adolescents with and at Risk for Depression::Protocol and Methods of the Identifying Depression Early in Adolescence Risk Stratified Cohort (IDEA-RiSCo) Longitudinal Assessments

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    Objective: To present the protocol and methods for the prospective longitudinal assessments — including clinical and digital phenotyping approaches — of the Identifying Depression Early in Adolescence Risk Stratified Cohort (IDEA-RiSCo) study, which comprises Brazilian adolescents stratified at baseline by risk of developing depression or presence of depression. Method: Of 7,720 screened adolescents aged 14-16, we recruited 150 participants (75 boys, 75 girls) based on a composite risk score: 50 with low risk for developing depression (LR), 50 with high risk for developing depression (HR), and 50 with an active untreated major depressive episode (MDD). Three annual follow-up assessments were conducted, involving clinical measures (parent and adolescent-reported questionnaires and psychiatrist assessments), active and passive data sensing via smartphones, and neurobiological measures (neuroimaging and biological material samples). Retention rates were 96% (Wave 1), 94% (Wave 2), and 88% (Wave 3), with no significant differences by sex or group (p &gt; 0.05). Participants highlighted their familiarity with the research team and assessment process as a motivator for sustained engagement.Discussion: This protocol relied on novel aspects, such as the use of a WhatsApp bot, which is particularly pertinent for low-to-middle-income countries, and the collection of information from diverse sources in a longitudinal design, encompassing clinical data, self-reports, parental reports, GPS data, and ecological momentary assessments. The study engaged adolescents over an extensive period and demonstrated the feasibility of conducting a prospective follow-up study with a risk-enriched cohort of adolescents in a middle-income country, integrating mobile technology with traditional methodologies to enhance longitudinal data collection. <br/

    Modeling How Humans Judge Dot-Label Relations in Point Cloud Visualizations

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    When point clouds are labeled in information visualization applications, sophisticated guidelines as in cartography do not yet exist. Existing naive strategies may mislead as to which points belong to which label. To inform improved strategies, we studied factors influencing this phenomenon. We derived a class of labeled point cloud representations from existing applications and we defined different models predicting how humans interpret such complex representations, focusing on their geometric properties. We conducted an empirical study, in which participants had to relate dots to labels in order to evaluate how well our models predict. Our results indicate that presence of point clusters, label size, and angle to the label have an effect on participants’ judgment as well as that the distance measure types considered perform differently discouraging the use of label centers as reference points

    Between imide, imidyl and nitrene – an imido iron complex in two oxidation states

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    Imidyl and nitrene metal species play an important role in the N-functionalisation of unreactive C–H bonds as well as the aziridination of olefines. We report on the synthesis of the trigonal imido iron complexes [Fe(NMes)L2]0,- (L ¼ –N{Dipp}SiMe3); Dipp ¼ 2,6-diisopropyl-phenyl; Mes ¼ (2,4,6-trimethylphenyl) via reaction of mesityl azide (MesN3) with the linear iron precursors [FeL2]0,-. UV-vis-, EPR-, 57Fe M¨ossbauer spectroscopy, magnetometry, and computational methods suggest for the reduced form an electronic structure as a ferromagnetically coupled iron(II) imidyl radical, whereas oxidation leads to mixed iron(III) imidyl and electrophilic iron(II) nitrene character. Reactivity studies show that both complexes are capable of H atom abstraction from C–H bonds. Further, the reduced form [Fe(NMes)L2]- reacts nucleophilically with CS2 by inserting into the imido iron bond, as well as electrophilically with CO under nitrene transfer. The neutral [Fe(NMes)L2] complex shows enhanced electrophilic behavior as evidenced by nitrene transfer to a phosphine, yet in combination with an overall reduced reactivity

    Between imide, imidyl and nitrene – an imido iron complex in two oxidation states

    No full text
    Imidyl and nitrene metal species play an important role in the N-functionalisation of unreactive C–H bonds as well as the aziridination of olefines. We report on the synthesis of the trigonal imido iron complexes [Fe(NMes)L2]0,− (L = –N{Dipp}SiMe3); Dipp = 2,6-diisopropyl-phenyl; Mes = (2,4,6-trimethylphenyl) via reaction of mesityl azide (MesN3) with the linear iron precursors [FeL2]0,−. UV-vis-, EPR-, 57Fe Mössbauer spectroscopy, magnetometry, and computational methods suggest for the reduced form an electronic structure as a ferromagnetically coupled iron(II) imidyl radical, whereas oxidation leads to mixed iron(III) imidyl and electrophilic iron(II) nitrene character. Reactivity studies show that both complexes are capable of H atom abstraction from C–H bonds. Further, the reduced form [Fe(NMes)L2]− reacts nucleophilically with CS2 by inserting into the imido iron bond, as well as electrophilically with CO under nitrene transfer. The neutral [Fe(NMes)L2] complex shows enhanced electrophilic behavior as evidenced by nitrene transfer to a phosphine, yet in combination with an overall reduced reactivity

    Measurement of the impact-parameter dependent azimuthal anisotropy in coherent ρ0 photoproduction in Pb–Pb collisions at √sNN = 5.02 TeV

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    The first measurement of the impact-parameter dependent angular anisotropy in the decay of coherently photoproduced ρ0 mesons is presented. The ρ0 mesons are reconstructed through their decay into a pion pair. The measured anisotropy corresponds to the amplitude of the cos(2ϕ) modulation, where ϕ is the angle between the two vectors formed by the sum and the difference of the transverse momenta of the pions, respectively. The measurement was performed by the ALICE Collaboration at the LHC using data from ultraperipheral Pb−Pb collisions at a center-of-mass energy of sNN−−−√ = 5.02 TeV per nucleon pair. Different impact-parameter regions are selected by classifying the events in nuclear-breakup classes. The amplitude of the cos(2ϕ) modulation is found to increase by about one order of magnitude from large to small impact parameters. Theoretical calculations, which describe the measurement, explain the cos(2ϕ) anisotropy as the result of a quantum interference effect at the femtometer scale that arises from the ambiguity as to which of the nuclei is the source of the photon in the interaction

    Investigating strangeness enhancement in jet and medium via ϕ\phi(1020) production in p-Pb collisions at sNN\sqrt{s_{\rm NN}} = 5.02 TeV

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    International audienceThis work aims to differentiate strangeness produced from hard processes (jet-like) and softer processes (underlying event) by measuring the angular correlation between a high-momentum trigger hadron (h) acting as a jet-proxy and a produced strange hadron (ϕ(1020)\phi(1020) meson). Measuring hϕ-\phi correlations at midrapidity in p-Pb collisions at sNN\sqrt{s_{\rm NN}} = 5.02 TeV as a function of event multiplicity provides insight into the microscopic origin of strangeness enhancement in small collision systems. The jet-like and the underlying-event-like strangeness production are investigated as a function of event multiplicity. They are also compared between a lower and higher momentum region. The evolution of the per-trigger yields within the near-side (aligned with the trigger hadron) and away-side (in the opposite direction of the trigger hadron) jet is studied separately, allowing for the characterization of two distinct jet-like production regimes. Furthermore, the hϕ-\phi correlations within the underlying event give access to a production regime dominated by soft production processes, which can be compared directly to the in-jet production. Comparisons between hϕ-\phi and dihadron correlations show that the observed strangeness enhancement is largely driven by the underlying event, where the ϕ/h\phi/\mathrm{h} ratio is significantly larger than within the jet regions. As multiplicity increases, the fraction of the total ϕ(1020)\phi(1020) yield coming from jets decreases compared to the underlying event production, leading to high-multiplicity events being dominated by the increased strangeness production from the underlying event

    Measurement of Λ3H{}_{\Lambda}^{3}\mathrm{H} production in Pb-Pb collisions at sNN\sqrt{s_{\mathrm{NN}}} = 5.02 TeV

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    International audienceThe first measurement of Λ3H_{\Lambda}^{3}\mathrm{H} and Λ3H^3_ {\overline{\Lambda}}\overline{\mathrm{H}} differential production with respect to transverse momentum and centrality in Pb-Pb collisions at sNN=5.02\sqrt{s_{\mathrm{NN}}}=5.02~TeV is presented. The Λ3H_{\Lambda}^{3}\mathrm{H} has been reconstructed via its two-charged-body decay channel, i.e., Λ3H3He+π_{\Lambda}^{3}\mathrm{H} \rightarrow {}^{3}\mathrm{He} + \pi^{-}. A Blast-Wave model fit of the pTp_{\rm T}-differential spectra of all nuclear species measured by the ALICE collaboration suggests that the Λ3H_{\Lambda}^{3}\mathrm{H} kinetic freeze-out surface is consistent with that of other nuclei. The ratio between the integrated yields of Λ3H_{\Lambda}^{3}\mathrm{H} and 3He^3\mathrm{He} is compared to predictions from the statistical hadronisation model and the coalescence model, with the latter being favoured by the presented measurements

    Investigating Λ\Lambda baryon production in p-Pb collisions in jets and underlying event using angular correlations

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    International audienceFirst measurements of hadron(h)Λ-\Lambda azimuthal angular correlations in p-Pb collisions at sNN\sqrt{s_{\rm NN}} = 5.02 TeV using the ALICE detector at the LHC are presented. These correlations are used to separate the production of associated Λ\Lambda baryons into three different kinematic regions, namely those produced in the direction of the trigger particle (near-side), those produced in the opposite direction (away-side), and those whose production is uncorrelated with the jet-axis (underlying event). The per-trigger associated Λ\Lambda yields in these regions are extracted, along with the near- and away-side azimuthal peak widths, and the results are studied as a function of associated particle pTp_{\rm T} and event multiplicity. Comparisons with the DPMJET event generator and previous measurements of the ϕ(1020)\phi(1020) meson are also made. The final results indicate that strangeness production in the highest multiplicity p-Pb collisions is enhanced relative to low multiplicity collisions in the jet-like regions, as well as the underlying event. The production of Λ\Lambda relative to charged hadrons is also enhanced in the underlying event when compared to the jet-like regions. Additionally, the results hint that strange quark production in the away-side of the jet is modified by soft interactions with the underlying event

    Particle production as a function of charged-particle flattenicity in pp collisions at s\sqrt{s} = 13 TeV

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    International audienceThis paper reports the first measurement of the transverse momentum (pTp_{\mathrm{T}}) spectra of primary charged pions, kaons, (anti)protons, and unidentified particles as a function of the charged-particle flattenicity in pp collisions at s=13\sqrt{s}=13 TeV. Flattenicity is a novel event shape observable that is measured in the pseudorapidity intervals covered by the V0 detector, 2.8<η<5.12.8<\eta<5.1 and 3.7<η<1.7-3.7<\eta<-1.7. According to QCD-inspired phenomenological models, it shows sensitivity to multiparton interactions and is less affected by biases towards larger pTp_{\mathrm{T}} due to local multiplicity fluctuations in the V0 acceptance than multiplicity. The analysis is performed in minimum-bias (MB) as well as in high-multiplicity events up to pT=20p_{\mathrm{T}}=20 GeV/cc. The event selection requires at least one charged particle produced in the pseudorapidity interval η<1|\eta|<1. The measured pTp_{\mathrm{T}} distributions, average pTp_{\mathrm{T}}, kaon-to-pion and proton-to-pion particle ratios, presented in this paper, are compared to model calculations using PYTHIA 8 based on color strings and EPOS LHC. The modification of the pTp_{\mathrm{T}}-spectral shapes in low-flattenicity events that have large event activity with respect to those measured in MB events develops a pronounced peak at intermediate pTp_{\mathrm{T}} (2<pT<82<p_{\mathrm{T}}<8 GeV/cc), and approaches the vicinity of unity at higher pTp_{\mathrm{T}}. The results are qualitatively described by PYTHIA, and they show different behavior than those measured as a function of charged-particle multiplicity based on the V0M estimator

    Exclusive four pion photoproduction in ultraperipheral Pb-Pb collisions at sNN=5.02\sqrt{s_{\rm NN}} = 5.02 TeV

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    International audienceThe intense photon fluxes from relativistic nuclei provide an opportunity to study photonuclear interactions in ultraperipheral collisions. The measurement of coherently photoproduced π+ππ+π\pi^+\pi^-\pi^+\pi^- final states in ultraperipheral Pb-Pb collisions at sNN=5.02\sqrt{s_{\mathrm{NN}}}=5.02 TeV is presented for the first time. The cross section, dσ\sigma/dyy, times the branching ratio (ρπ+π+ππ\rho\rightarrow \pi^+ \pi^+ \pi^- \pi^-) is found to be 47.8±2.3 (stat.)±7.7 (syst.)47.8\pm2.3~\rm{(stat.)}\pm7.7~\rm{(syst.)} mb in the rapidity interval y<0.5|y| < 0.5. The invariant mass distribution is not well described with a single Breit-Wigner resonance. The production of two interfering resonances, ρ(1450)\rho(1450) and ρ(1700)\rho(1700), provides a good description of the data. The values of the masses (mm) and widths (Γ\Gamma) of the resonances extracted from the fit are m1=1385±14 (stat.)±3 (syst.)m_{1}=1385\pm14~\rm{(stat.)}\pm3~\rm{(syst.)} MeV/c2c^2, Γ1=431±36 (stat.)±82 (syst.)\Gamma_{1}=431\pm36~\rm{(stat.)}\pm82~\rm{(syst.)} MeV/c2c^2, m2=1663±13 (stat.)±22 (syst.)m_{2}=1663\pm13~\rm{(stat.)}\pm22~\rm{(syst.)} MeV/c2c^2 and Γ2=357±31 (stat.)±49 (syst.)\Gamma_{2}=357 \pm31~\rm{(stat.)}\pm49~\rm{(syst.)} MeV/c2c^2, respectively. The measured cross sections times the branching ratios are compared to recent theoretical predictions
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