115 research outputs found
Quantum-limited measurements of optical signals from a geostationary satellite
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!
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
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The function-dominance correlation drives the direction and strength of biodiversity-ecosystem functioning relationships
Community composition is a primary determinant of how biodiversity change influences ecosystem functioning and, therefore, the relationship between biodiversity and ecosystem functioning (BEF). We examine the consequences of community composition across six structurally realistic plant community models. We find that a positive correlation between species' functioning in monoculture versus their dominance in mixture with regard to a specific function (the "function-dominance correlation") generates a positive relationship between realised diversity and ecosystem functioning across species richness treatments. However, because realised diversity declines when few species dominate, a positive function-dominance correlation generates a negative relationship between realised diversity and ecosystem functioning within species richness treatments. Removing seed inflow strengthens the link between the function-dominance correlation and BEF relationships across species richness treatments but weakens it within them. These results suggest that changes in species' identities in a local species pool may more strongly affect ecosystem functioning than changes in species richness
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From Next-Generation Sequencing Alignments to Accurate Comparison and Validation of Single-Nucleotide Variants: The Pibase Software
Scientists working with single-nucleotide variants (SNVs), inferred by next-generation sequencing software, often need further information regarding true variants, artifacts and sequence coverage gaps. In clinical diagnostics, e.g. SNVs must usually be validated by visual inspection or several independent SNV-callers. We here demonstrate that 0.5–60% of relevant SNVs might not be detected due to coverage gaps, or might be misidentified. Even low error rates can overwhelm the true biological signal, especially in clinical diagnostics, in research comparing healthy with affected cells, in archaeogenetic dating or in forensics. For these reasons, we have developed a package called pibase, which is applicable to diploid and haploid genome, exome or targeted enrichment data. pibase extracts details on nucleotides from alignment files at user-specified coordinates and identifies reproducible genotypes, if present. In test cases pibase identifies genotypes at 99.98% specificity, 10-fold better than other tools. pibase also provides pair-wise comparisons between healthy and affected cells using nucleotide signals (10-fold more accurately than a genotype-based approach, as we show in our case study of monozygotic twins). This comparison tool also solves the problem of detecting allelic imbalance within heterozygous SNVs in copy number variation loci, or in heterogeneous tumor sequences
The UNITE database for molecular identification and taxonomic communication of fungi and other eukaryotes : sequences, taxa and classifications reconsidered
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
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
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 m 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 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
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 (R600) transmission
spectrum of an exoplanet atmosphere between 3-5 m 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
CO (28.5) and HO (21.5), and identify SO as the
source of absorption at 4.1 m (4.8). 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 SO, 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
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 m, exhibit minimal systematics,
and reveal well-defined molecular absorption features in the planet's spectrum.
Specifically, we detect gaseous HO in the atmosphere and place an upper
limit on the abundance of CH. The otherwise prominent CO feature at 2.8
m is largely masked by HO. The best-fit chemical equilibrium models
favour an atmospheric metallicity of 1-100 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
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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