40 research outputs found
Cyclic transformation of orbital angular momentum modes
The spatial modes of photons are one realization of a QuDit, a quantum system
that is described in a D-dimensional Hilbert space. In order to perform quantum
information tasks with QuDits, a general class of D-dimensional unitary
transformations is needed. Among these, cyclic transformations are an important
special case required in many high-dimensional quantum communication protocols.
In this paper, we experimentally demonstrate a cyclic transformation in the
high-dimensional space of photonic orbital angular momentum (OAM). Using simple
linear optical components, we show a successful four-fold cyclic transformation
of OAM modes. Interestingly, our experimental setup was found by a computer
algorithm. In addition to the four-cyclic transformation, the algorithm also
found extensions to higher-dimensional cycles in a hybrid space of OAM and
polarization. Besides being useful for quantum cryptography with QuDits, cyclic
transformations are key for the experimental production of high-dimensional
maximally entangled Bell-states.Comment: 18 pages, 6 figure
Comparative morphology of the mouthparts of the megadiverse South African monkey beetles (Scarabaeidae: Hopliini): feeding adaptations and guild structure
Although anthophilous Coleoptera are regarded to be unspecialised flower-visiting insects, monkey beetles (Scarabaeidae: Hopliini) represent one of the most important groups of pollinating insects in South Africa’s floristic hotspot of the Greater Cape Region. South African monkey beetles are known to feed on floral tissue; however, some species seem to specialise on pollen and/or nectar. The present study examined the mouthpart morphology and gut content of various hopliine species to draw conclusions on their feeding preferences. According to the specialisations of their mouthparts, the investigated species were classified into different feeding groups. Adaptations to pollen-feeding included a well-developed, toothed molar and a lobe-like, setose lacinia mobilis on the mandible as well as curled hairs or sclerotized teeth on the galea of the maxillae. Furthermore, elongated mouthparts were interpreted as adaptations for nectar feeding. Floral- and folial-tissue feeding species showed sclerotized teeth on the maxilla, but the lacinia was mostly found to be reduced to a sclerotized ledge. While species could clearly be identified as floral or folial tissue feeding, several species showed intermediate traits suggesting both pollen and nectar feeding adaptations. Mismatches found between mouthpart morphology and previously reported flower visiting behaviours across different genera and species requires alternative explanations, not necessarily associated with feeding preferences. Although detailed examinations of the mouthparts allowed conclusions about the feeding preference and flower-visiting behaviour, additional morphological and behavioural investigations, combined with greater taxon sampling and phylogenetic data, are still necessary to fully understand hopliine host plant relationships, related to monkey beetle diversity
Self-referencing embedded strings (SELFIES): A 100% robust molecular string representation
The discovery of novel materials and functional molecules can help to solve
some of society's most urgent challenges, ranging from efficient energy
harvesting and storage to uncovering novel pharmaceutical drug candidates.
Traditionally matter engineering -- generally denoted as inverse design -- was
based massively on human intuition and high-throughput virtual screening. The
last few years have seen the emergence of significant interest in
computer-inspired designs based on evolutionary or deep learning methods. The
major challenge here is that the standard strings molecular representation
SMILES shows substantial weaknesses in that task because large fractions of
strings do not correspond to valid molecules. Here, we solve this problem at a
fundamental level and introduce SELFIES (SELF-referencIng Embedded Strings), a
string-based representation of molecules which is 100\% robust. Every SELFIES
string corresponds to a valid molecule, and SELFIES can represent every
molecule. SELFIES can be directly applied in arbitrary machine learning models
without the adaptation of the models; each of the generated molecule candidates
is valid. In our experiments, the model's internal memory stores two orders of
magnitude more diverse molecules than a similar test with SMILES. Furthermore,
as all molecules are valid, it allows for explanation and interpretation of the
internal working of the generative models.Comment: 6+3 pages, 6+1 figure
Making large music collections accessible using enhanced metadata and lightweight visualizations
Abstrac
Time management and nectar flow: flower handling and suction feeding in long-proboscid flies (Nemestrinidae: Prosoeca)
A well-developed suction pump in the head represents an important adaptation for nectar-feeding insects, such as Hymenoptera, Lepidoptera and Diptera. This pumping organ creates a pressure gradient along the proboscis, which is responsible for nectar uptake. The extremely elongated proboscis of the genus Prosoeca (Nemestrinidae) evolved as an adaptation to feeding from long, tubular flowers. According to the functional constraint hypothesis, nectar uptake through a disproportionately elongated, straw-like proboscis increases flower handling time and consequently lowers the energy intake rate. Due to the conspicuous length variation of the proboscis of Prosoeca, individuals with longer proboscides are hypothesised to have longer handling times. To test this hypothesis, we used field video analyses of flower-visiting behaviour, detailed examinations of the suction pump morphology and correlations of proboscis length with body length and suction pump dimensions. Using a biomechanical framework described for nectar-feeding Lepidoptera in relation to proboscis length and suction pump musculature, we describe and contrast the system in long-proboscid flies. Flies with longer proboscides spent significantly more time drinking from flowers. In addition, proboscis length and body length showed a positive allometric relationship. Furthermore, adaptations of the suction pump included an allometric relationship between proboscis length and suction pump muscle volume and a combination of two pumping organs. Overall, the study gives detailed insight into the adaptations required for long-proboscid nectar feeding, and comparisons with other nectar-sucking insects allow further considerations of the evolution of the suction pump in insects with sucking mouthparts. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00114-013-1114-6) contains supplementary material, which is available to authorized users
On scientific understanding with artificial intelligence
Imagine an oracle that correctly predicts the outcome of every particle
physics experiment, the products of every chemical reaction, or the function of
every protein. Such an oracle would revolutionize science and technology as we
know them. However, as scientists, we would not be satisfied with the oracle
itself. We want more. We want to comprehend how the oracle conceived these
predictions. This feat, denoted as scientific understanding, has frequently
been recognized as the essential aim of science. Now, the ever-growing power of
computers and artificial intelligence poses one ultimate question: How can
advanced artificial systems contribute to scientific understanding or achieve
it autonomously?
We are convinced that this is not a mere technical question but lies at the
core of science. Therefore, here we set out to answer where we are and where we
can go from here. We first seek advice from the philosophy of science to
understand scientific understanding. Then we review the current state of the
art, both from literature and by collecting dozens of anecdotes from scientists
about how they acquired new conceptual understanding with the help of
computers. Those combined insights help us to define three dimensions of
android-assisted scientific understanding: The android as a I) computational
microscope, II) resource of inspiration and the ultimate, not yet existent III)
agent of understanding. For each dimension, we explain new avenues to push
beyond the status quo and unleash the full power of artificial intelligence's
contribution to the central aim of science. We hope our perspective inspires
and focuses research towards androids that get new scientific understanding and
ultimately bring us closer to true artificial scientists.Comment: 13 pages, 3 figures, comments welcome
Clinical relevance of lung transplantation for COVID-19 ARDS: a nationwide study
BACKGROUND: Although the number of lung transplantations (LTx) performed worldwide for COVID-19 induced acute respiratory distress syndrome (ARDS) is still low, there is general agreement that this treatment can save a subgroup of most severly ill patients with irreversible lung damage. However, the true proportion of patients eligible for LTx, the overall outcome and the impact of LTx to the pandemic are unknown. METHODS: A retrospective analysis was performed using a nationwide registry of hospitalised patients with confirmed severe acute respiratory syndrome coronavirus type 2 (SARS-Cov-2) infection admitted between January 1, 2020 and May 30, 2021 in Austria. Patients referred to one of the two Austrian LTx centers were analyzed and grouped into patients accepted and rejected for LTx. Detailed outcome analysis was performed for all patients who received a LTx for post-COVID-19 ARDS and compared to patients who underwent LTx for other indications. RESULTS: Between January 1, 2020 and May 30, 2021, 39.485 patients were hospitalised for COVID-19 in Austria. 2323 required mechanical ventilation, 183 received extra-corporeal membrane oxygenation (ECMO) support. 106 patients with severe COVID-19 ARDS were referred for LTx. Of these, 19 (18%) underwent LTx. 30-day mortality after LTx was 0% for COVID-19 ARDS transplant recipients. With a median follow-up of 134 (47–450) days, 14/19 patients are alive. CONCLUSIONS: Early referral of ECMO patients to a LTx center is pivotal in order to select patients eligible for LTx. Transplantation offers excellent midterm outcomes and should be incorporated in the treatment algorithm of post-COVID-19 ARDS
Genomic investigations of unexplained acute hepatitis in children
Since its first identification in Scotland, over 1,000 cases of unexplained paediatric hepatitis in children have been reported worldwide, including 278 cases in the UK1. Here we report an investigation of 38 cases, 66 age-matched immunocompetent controls and 21 immunocompromised comparator participants, using a combination of genomic, transcriptomic, proteomic and immunohistochemical methods. We detected high levels of adeno-associated virus 2 (AAV2) DNA in the liver, blood, plasma or stool from 27 of 28 cases. We found low levels of adenovirus (HAdV) and human herpesvirus 6B (HHV-6B) in 23 of 31 and 16 of 23, respectively, of the cases tested. By contrast, AAV2 was infrequently detected and at low titre in the blood or the liver from control children with HAdV, even when profoundly immunosuppressed. AAV2, HAdV and HHV-6 phylogeny excluded the emergence of novel strains in cases. Histological analyses of explanted livers showed enrichment for T cells and B lineage cells. Proteomic comparison of liver tissue from cases and healthy controls identified increased expression of HLA class 2, immunoglobulin variable regions and complement proteins. HAdV and AAV2 proteins were not detected in the livers. Instead, we identified AAV2 DNA complexes reflecting both HAdV-mediated and HHV-6B-mediated replication. We hypothesize that high levels of abnormal AAV2 replication products aided by HAdV and, in severe cases, HHV-6B may have triggered immune-mediated hepatic disease in genetically and immunologically predisposed children
Erschließung von Prozessmodellen durch Multiperspektivität
Die steigende Komplexität von (Geschäfts-)Prozessen beeinflusst die Verständlichkeit von Prozessmodellen und kann dadurch deren Einsatz erschweren. Das Geschäftsprozessmanagement sieht sich vor der Herausforderung die Anwendbarkeit von Geschäftsprozessmodellen entlang des BPM-Lifecycle für alle Stakeholder trotz der Komplexitätssteigerung zu gewährleisten. Der Schwerpunkt der BPM-Forschung lag diesbezüglich in den vergangenen Jahren auf der Reduktion der intrinsischen Belastung bei der Modellarbeit. Das Unterstützungspotential von Ansätzen zur Reduktion der extrinsischen Belastung hingegen wurde zwar erkannt, aber noch nicht eingehend untersucht. In dieser Arbeit wird das Potential eines Ansatzes zur Reduktion der extrinsischen kognitiven Belastung empirisch untersucht. Dieser Ansatz berücksichtigt zwei ausgezeichnete Perspektiven sowie den dynamischen Perspektivenwechsel und untersucht deren Auswirkung auf die Prozessmodellverständlichkeit. In einer ersten empirischen Untersuchung konnten Indikatoren aufgezeigt werden, die auf eine Unterstützung des Prozessmodellverständlichkeitsbildungsprozesses durch Synergieeffekte hindeuten, die bei der Verwendung mehrerer, auf sich abgestimmter Perspektiven auftreten.eingereicht von Florian Krenn, Bsc MScUniversität Linz, Dissertation, 2018OeBB(VLID)258192