A comparative study of satellite and ground-based phenology

Long time series of ground-based plant phenology, as well as more than two decades of satellite-derived phenological metrics, are currently available to assess the impacts of climate variability and trends on terrestrial vegetation. Traditional plant phenology provides very accurate information on individual plant species, but with limited spatial coverage. Satellite phenology allows monitoring of terrestrial vegetation on a global scale and provides an integrative view at the landscape level. Linking the strengths of both methodologies has high potential value for climate impact studies. We compared a multispecies index from ground-observed spring phases with two types (maximum slope and threshold approach) of satellite-derived start-of-season (SOS) metrics. We focus on Switzerland from 1982 to 2001 and show that temporal and spatial variability of the multispecies index correspond well with the satellite-derived metrics. All phenological metrics correlate with temperature anomalies as expected. The slope approach proved to deviate strongly from the temporal development of the ground observations as well as from the threshold-defined SOS satellite measure. The slope spring indicator is considered to indicate a different stage in vegetation development and is therefore less suited as a SOS parameter for comparative studies in relation to ground-observed phenology. Satellite-derived metrics are, however, very susceptible to snow cover, and it is suggested that this snow cover should be better accounted for by the use of newer satellite sensor

Kann die 18F-FDG-PET/CT-Untersuchung die Panendoskopie zur Detektion von synchronen Zweitkarzinomen ersetzen?

Ziel der Arbeit war es, die Wertigkeit der 18F-FDG-PET/ CT-Untersuchung bezüglich synchroner Zweitkarzinome im Vergleich mit der Panendoskopie beim initialen Staging zu untersuchen. 311 Patienten wurden mit beiden Untersuchungsmethoden abgeklärt. Als Referenz galt die zytologische, histologische und/oder klinische oder radiologische Untersuchung. Die Prävalenz für synchrone Zweitkarzinome betrug mit der Panendoskopie 4,5%, während die Prävalenz mittels PET/ CT-Untersuchung 6,1% betrug. Die Sensitivität für die Panendoskopie betrug 74%, die Spezifität 99,7%, der positiv prädiktive Wert 93% und der negativ prädiktive Wert 98%. Die Sensitivität für die PET/CT-Untersuchung betrug 100%, die Spezifität 95,7% der positiv prädiktive Wert 59% und der negativ prädiktive Wert 100%. Die PET/CT-Untersuchung scheint der Panendoskopie überlegen zu sein. Bei bezüglich synchroner Zweitkarzinome unauffälligem PET/CT kann die Panendoskopie auf die Endoskopie und Beurteilung des Primärtumors beschränkt werden kann. Aufgrund der hohen Kosten und der grossen Anzahl falsch positiver Resultate, welche durch das PET/CT generiert werden, empfehlen wir die Durchführung dieser Untersuchung nur bei fortgeschrittenen Tumoren mit der Frage nach Fernmetastasen. Die Panendoskopie bleibt weiterhin der Goldstandar

Pelvic organ movements in asymptomatic nulliparous and symptomatic premenopausal women with pelvic organ prolapse in dynamic MRI: a feasibility study comparing midsagittal single-slice with multi-slice sequences

PURPOSE To compare multi-slice (MS) MRI sequences of the pelvis acquired at rest and straining to dynamic midsagittal single-slice (SS) sequences for the assessment of pelvic organ prolapse (POP). METHODS This IRB-approved prospective single-center feasibility study included 23 premenopausal symptomatic patients with POP and 22 asymptomatic nulliparous volunteers. MRI of the pelvis at rest and straining was performed with midsagittal SS and MS sequences. Straining effort, visibility of organs and POP grade were scored on both. Organ points (bladder, cervix, anorectum) were measured. Differences between SS and MS sequences were compared with Wilcoxon test. RESULTS Straining effort was good in 84.4% on SS and in 64.4% on MS sequences (p = 0.003). Organ points were always visible on MS sequences, whereas the cervix was not fully visible in 31.1-33.3% on SS sequences. At rest, there were no statistically significant differences of organ point measurements between SS and MS sequences in symptomatic patients. At straining, positions of bladder, cervix, and anorectum were + 1.1 cm (± 1.8 cm), - 0.7 cm (± 2.9 cm), and + 0.7 cm (± 1.3 cm) on SS and + 0.4 mm (± 1.7 cm), - 1.4 cm (± 2.6 cm), and + 0.4 cm (± 1.3 cm) on MS sequences (p < 0.05). Only 2 cases of higher-grade POP were missed on MS sequences (both with poor straining effort). CONCLUSION MS sequences increase the visibility of organ points compared to SS sequences. Dynamic MS sequences can depict POP if images are acquired with sufficient straining effort. Further work is needed to optimize the depiction of the maximum straining effort with MS sequences

Combining Monte Carlo generators with next-to-next-to-leading order calculations: event reweighting for Higgs boson production at the LHC

We study a phenomenological ansatz for merging next-to-next-to-leading order (NNLO) calculations with Monte Carlo event generators. We reweight them to match bin-integrated NNLO differential distributions. To test this procedure, we study the Higgs boson production cross-section at the LHC, for which a fully differential partonic NNLO calculation is available. We normalize PYTHIA and MC@NLO Monte Carlo events for Higgs production in the gluon fusion channel to reproduce the bin integrated NNLO double differential distribution in the transverse momentum and rapidity of the Higgs boson. These events are used to compute differential distributions for the photons in the pp \to H \to \gamma \gamma decay channel, and are compared to predictions from fixed-order perturbation theory at NNLO. We find agreement between the reweighted generators and the NNLO result in kinematic regions where we expect a good description using fixed-order perturbation theory. Kinematic boundaries where resummation is required are also modeled correctly using this procedure. We then use these events to compute distributions in the pp \to H \to W^+W^- \to l^+l^- \nu\bar{\nu} channel, for which an accurate description is needed for measurements at the LHC. We find that the final state lepton distributions obtained from PYTHIA are not significantly changed by the reweighting procedure.Comment: 18 pages, 14 fig

NNLO QCD predictions for the H -> WW -> l l nu nu signal at the LHC

We present a first computation of the NNLO QCD cross section at the LHC for the production of four leptons from a Higgs boson decaying into W bosons. We study the cross section for a Higgs boson mass Mh = 165 GeV; around this value a Standard Model Higgs boson decays almost exclusively into W-pairs. We apply all nominal experimental cuts on the final state leptons and the associated jet activity and study the magnitude of higher-order effects up to NNLO on all kinematic variables which are constrained by experimental cuts. We find that the magnitude of the higher-order corrections varies significantly with the signal selection cuts. As a main result we give the value of the cross section at NNLO with all selection cuts envisaged for the search for the Higgs boson.Comment: typos corrected, version accepted in JHE

Perturbative QCD effects and the search for a H->WW->l nu l nu signal at the Tevatron

The Tevatron experiments have recently excluded a Standard Model Higgs boson in the mass range 160 - 170 GeV at the 95% confidence level. This result is based on sophisticated analyses designed to maximize the ratio of signal and background cross-sections. In this paper we study the production of a Higgs boson of mass 160 GeV in the gg -> H -> WW -> l nu l nu channel. We choose a set of cuts like those adopted in the experimental analysis and compare kinematical distributions of the final state leptons computed in NNLO QCD to lower-order calculations and to those obtained with the event generators PYTHIA, HERWIG and MC@NLO. We also show that the distribution of the output from an Artificial Neural Network obtained with the different tools does not show significant differences. However, the final acceptance computed with PYTHIA is smaller than those obtained at NNLO and with HERWIG and MC@NLO. We also investigate the impact of the underlying event and hadronization on our results.Comment: Extra discussion and references adde

Strong coupling theory for driven tunneling and vibrational relaxation

We investigate on a unified basis tunneling and vibrational relaxation in driven dissipative multistable systems described by their N lowest lying unperturbed levels. By use of the discrete variable representation we derive a set of coupled non-Markovian master equations. We present analytical treatments that describe the dynamics in the regime of strong system-bath coupling. Our findings are corroborated by ``ab-initio'' real-time path integral calculations.Comment: 4 LaTeX pages including 3 figure

Social corrections act as a double-edged sword by reducing the perceived accuracy of false and real news in the UK, Germany, and Italy

This is the final version. Available from Nature Research via the DOI in this record. Data availability: All shareable data are found on the online OSF repository at https://osf.io/jhwfgCode availability: All the code including reproducible analyses are found on the online OSF repository at https://osf.io/4hjcf for data relating to the UK, https://osf.io/yvdj4 for Italy, and https:// osf.io/jhwfg Germany.Corrective or refutational posts from ordinary users on social media have the potential to improve the online information ecosystem. While initial evidence of these social corrections is promising, a better understanding of the effects across different topics, formats, and audiences is needed. In three pre-registered experiments (N = 1944 UK, N = 2467 Italy, N = 2210 Germany) where respondents completed a social media post assessment task with false and true news posts on various topics (e.g., health, climate change, technology), we find that social corrections reduce perceived accuracy of and engagement with false news posts. We also find that social corrections that flag true news as false decrease perceived accuracy of and engagement with true news posts. We did not find evidence to support moderation of these effects by correction strength, anti-expert sentiments, cognitive reflection capacities, or susceptibility to social influence. While social corrections can be effective for false news, they may also undermine belief in true news.British AcademyDavidson Colleg