115 research outputs found

    Quantum-limited measurements of optical signals from a geostationary satellite

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    The measurement of quantum signals that traveled through long distances is of fundamental and technological interest. We present quantum-limited coherent measurements of optical signals, sent from a satellite in geostationary Earth orbit to an optical ground station. We bound the excess noise that the quantum states could have acquired after having propagated 38600 km through Earth's gravitational potential as well as its turbulent atmosphere. Our results indicate that quantum communication is feasible in principle in such a scenario, highlighting the possibility of a global quantum key distribution network for secure communication.Comment: 8 pages (4 pages main article, 4 pages supplementary material), 9 figures (4 figures main article, 5 figures supplementary material), Kevin G\"unthner and Imran Khan contributed equally to this wor

    Teaching Tips – Gute Lehre ist kein Glücksfall!

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    Fragen wir die Teilnehmerinnen und Teilnehmer unserer hochschuldidaktischen Weiterbildungen nach ihren Erwartungen, so nennen sie an erster Stelle immer „konkrete Hilfestellungen für den Lehralltag“. Schauen wir genauer hin, wie diese Hilfestellungen aussehen könnten, so zeigen sich deutliche Unterschiede in den Zielgruppen der Lehrenden. Stehen sie noch am Anfang ihrer Lehrkarriere, wünschen sie sich besonders Hilfestellungen, die den Einstieg in die Lehre erleichtern bzw. ihnen helfen, effektiv zu lehren und effiziente Lehrende zu werden. Für erfahrene Lehrende hingegen, die zudem mit Prüfungen betraut sind, stellt sich darüber hinaus oft die Frage nach der Auswahl von Prüfungsformen und die Bewertung von Prüfungsleistungen, vor allem da ihnen die Modulabschlussprüfungen eine größere Bandbreite an Formen alternativer Leistungsbewertung eröffnen. Beiden Zielgruppen gemein ist die Suche nach praktischer Hilfe bei der Professionalisierung ihres didaktischen Handelns. Mit Patentrezepten ist ihnen dabei nicht gedient. Das Interesse der Lehrenden an Methoden wird gleichwohl als ein legitimes Interesse gesehen, denn Methodenwissen spielt bei der Vermittlung von Wissen eine große Rolle. Besonders im Kontext von Medialisierung werden die Vermittlungsmethoden wichtiger. Die hochschuldidaktische Weiterbildung will den Lehrenden bei der Entwicklung ihres individuellen und professionellen Lehrprofils theoretisch begründet, serviceorientiert zur Seite stehen. Seit Mitte der 1990er Jahre ist die didaktische Ausbildung für die Lehre nicht mehr dem Zufall überlassen, ebenso wie es keine Notwendigkeit mehr ist, sich hochschuldidaktisches Wissen autodidaktisch anzueignen. Die Entwicklung der Hochschuldidaktik und damit einhergehend die Entwicklung von curriculumbasierten, modularisierten und systematisch aufgebauten Weiterbildungsprogrammen hat in den letzten Jahrzehnten nicht zuletzt dank verschiedener Programme und Initiativen (z.B. Länderprogramme „Qualität der Lehre“, „Exzellenzinitiative“, BMBF, Stifterverband) eine enorme Steigerung erfahren. Die Qualität der Lehre an Universitäten ist zu einem Wettbewerbsfaktor unter den Universitäten geworden und kann zu ihrer Profilbildung beitragen. Die Lehrkompetenz kann als Schlüssel für die Qualität der Lehre gesehen werden und ist ein Merkmal akademischer Personalentwicklung. Dieses Journal soll in kleinem Rahmen als praxisorientierter Ratgeber auftreten. Es soll darüber hinaus das Interesse an hochschuldidaktischer Weiterbildung wecken, Lust machen, sich mit der eigenen Lehre auseinanderzusetzen, sich den kollegialen Fragen der anderen Teilnehmer/inne/n in den Workshops zu stellen, gemeinsam mit ihnen und uns, den Hochschuldidaktikern und Hochschuldidaktikerinnen, mögliche Antworten aufzuspüren und so das eigene Lehrrepertoire zu erweitern

    The UNITE database for molecular identification and taxonomic communication of fungi and other eukaryotes : sequences, taxa and classifications reconsidered

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    Acknowledgements We acknowledge Marie Zirk for her work in designing the UNITE logotype and creating the visual abstract for this article. Funding UNITE database development is financed by the Estonian Research Council [PRG1170]; European Union's Horizon 2020 project BGE [101059492]. The PlutoF digital infrastructure is supported by the European Union's Horizon 2020 project BiCIKL [101007492]; Estonian Research Infrastructure roadmap project DiSSCo Estonia. Funding for open access charge: UNITE Community. Conflict of interest statement. None declared.Peer reviewedPublisher PD

    Prehabilitation of elderly frail or pre-frail patients prior to elective surgery (PRAEP-GO): study protocol for a randomized, controlled, outcome assessor-blinded trial

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    Background: Frailty is expressed by a reduction in physical capacity, mobility, muscle strength, and endurance. (Pre-) frailty is present in up to 42% of the older surgical population, with an increased risk for peri- and postoperative complications. Consequently, these patients often suffer from a delayed or limited recovery, loss of autonomy and quality of life, and a decrease in functional and cognitive capacities. Since frailty is modifiable, prehabilitation may improve the physiological reserves of patients and reduce the care dependency 12 months after surgery. Methods: Patients >= 70 years old scheduled for elective surgery or intervention will be recruited in this multicenter, randomized controlled study, with a target of 1400 participants with an allocation ratio of 1:1. The intervention consists of (1) a shared decision-making process with the patient, relatives, and an interdisciplinary and interprofessional team and (2) a 3-week multimodal, individualized prehabilitation program including exercise therapy, nutritional intervention, mobility or balance training, and psychosocial interventions and medical assessment. The frequency of the supervised prehabilitation is 5 times/week for 3 weeks. The primary endpoint is defined as the level of care dependency 12 months after surgery or intervention. Discussion: Prehabilitation has been proven to be effective for different populations, including colorectal, transplant, and cardiac surgery patients. In contrast, evidence for prehabilitation in older, frail patients has not been clearly established. To the best of our knowledge, this is currently the largest prehabilitation study on older people with frailty undergoing general elective surgery

    Early Release Science of the exoplanet WASP-39b with JWST NIRISS

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    Transmission spectroscopy provides insight into the atmospheric properties and consequently the formation history, physics, and chemistry of transiting exoplanets. However, obtaining precise inferences of atmospheric properties from transmission spectra requires simultaneously measuring the strength and shape of multiple spectral absorption features from a wide range of chemical species. This has been challenging given the precision and wavelength coverage of previous observatories. Here, we present the transmission spectrum of the Saturn-mass exoplanet WASP-39b obtained using the SOSS mode of the NIRISS instrument on the JWST. This spectrum spans 0.62.8μ0.6 - 2.8 \mum in wavelength and reveals multiple water absorption bands, the potassium resonance doublet, as well as signatures of clouds. The precision and broad wavelength coverage of NIRISS-SOSS allows us to break model degeneracies between cloud properties and the atmospheric composition of WASP-39b, favoring a heavy element enhancement ("metallicity") of 1030×\sim 10 - 30 \times the solar value, a sub-solar carbon-to-oxygen (C/O) ratio, and a solar-to-super-solar potassium-to-oxygen (K/O) ratio. The observations are best explained by wavelength-dependent, non-gray clouds with inhomogeneous coverage of the planet's terminator.Comment: 48 pages, 12 figures, 2 tables. Under review at Natur

    Early Release Science of the Exoplanet WASP-39b with JWST NIRSpec G395H

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    Measuring the abundances of carbon and oxygen in exoplanet atmospheres is considered a crucial avenue for unlocking the formation and evolution of exoplanetary systems. Access to an exoplanet's chemical inventory requires high-precision observations, often inferred from individual molecular detections with low-resolution space-based and high-resolution ground-based facilities. Here we report the medium-resolution (R\sim600) transmission spectrum of an exoplanet atmosphere between 3-5 μ\mum covering multiple absorption features for the Saturn-mass exoplanet WASP-39b, obtained with JWST NIRSpec G395H. Our observations achieve 1.46x photon precision, providing an average transit depth uncertainty of 221 ppm per spectroscopic bin, and present minimal impacts from systematic effects. We detect significant absorption from CO2_2 (28.5σ\sigma) and H2_2O (21.5σ\sigma), and identify SO2_2 as the source of absorption at 4.1 μ\mum (4.8σ\sigma). Best-fit atmospheric models range between 3 and 10x solar metallicity, with sub-solar to solar C/O ratios. These results, including the detection of SO2_2, underscore the importance of characterising the chemistry in exoplanet atmospheres, and showcase NIRSpec G395H as an excellent mode for time series observations over this critical wavelength range.Comment: 44 pages, 11 figures, 3 tables. Resubmitted after revision to Natur

    Early Release Science of the exoplanet WASP-39b with JWST NIRCam

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    Measuring the metallicity and carbon-to-oxygen (C/O) ratio in exoplanet atmospheres is a fundamental step towards constraining the dominant chemical processes at work and, if in equilibrium, revealing planet formation histories. Transmission spectroscopy provides the necessary means by constraining the abundances of oxygen- and carbon-bearing species; however, this requires broad wavelength coverage, moderate spectral resolution, and high precision that, together, are not achievable with previous observatories. Now that JWST has commenced science operations, we are able to observe exoplanets at previously uncharted wavelengths and spectral resolutions. Here we report time-series observations of the transiting exoplanet WASP-39b using JWST's Near InfraRed Camera (NIRCam). The long-wavelength spectroscopic and short-wavelength photometric light curves span 2.0 - 4.0 μ\mum, exhibit minimal systematics, and reveal well-defined molecular absorption features in the planet's spectrum. Specifically, we detect gaseous H2_2O in the atmosphere and place an upper limit on the abundance of CH4_4. The otherwise prominent CO2_2 feature at 2.8 μ\mum is largely masked by H2_2O. The best-fit chemical equilibrium models favour an atmospheric metallicity of 1-100×\times solar (i.e., an enrichment of elements heavier than helium relative to the Sun) and a sub-stellar carbon-to-oxygen (C/O) ratio. The inferred high metallicity and low C/O ratio may indicate significant accretion of solid materials during planet formation or disequilibrium processes in the upper atmosphere.Comment: 35 pages, 13 figures, 3 tables, Nature, accepte

    FungalTraits:A user-friendly traits database of fungi and fungus-like stramenopiles

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    The cryptic lifestyle of most fungi necessitates molecular identification of the guild in environmental studies. Over the past decades, rapid development and affordability of molecular tools have tremendously improved insights of the fungal diversity in all ecosystems and habitats. Yet, in spite of the progress of molecular methods, knowledge about functional properties of the fungal taxa is vague and interpretation of environmental studies in an ecologically meaningful manner remains challenging. In order to facilitate functional assignments and ecological interpretation of environmental studies we introduce a user friendly traits and character database FungalTraits operating at genus and species hypothesis levels. Combining the information from previous efforts such as FUNGuild and Fun(Fun) together with involvement of expert knowledge, we reannotated 10,210 and 151 fungal and Stramenopila genera, respectively. This resulted in a stand-alone spreadsheet dataset covering 17 lifestyle related traits of fungal and Stramenopila genera, designed for rapid functional assignments of environmental studies. In order to assign the trait states to fungal species hypotheses, the scientific community of experts manually categorised and assigned available trait information to 697,413 fungal ITS sequences. On the basis of those sequences we were able to summarise trait and host information into 92,623 fungal species hypotheses at 1% dissimilarity threshold
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