We employ classical density-functional theory to investigate the phase diagram of an assembly of mutually penetrable, parallel ellipsoids interacting via the generalized exponential model of index four (GEM-4) pair potential. We show that the crystal phases of the system are obtained from those of the spherically symmetric GEM-4 model by rescaling the lattice vectors. Performing this rescaling in combination with an arbitrary rotation of the lattice leads to infinitely many different structures with the same free energy, thereby implying their infinite degeneracy. These findings generalize to non-zero temperature the results formerly obtained by us [Pini et al., J. Chem. Phys. 153, 164901 (2020)] for the ground state of a similar system of ellipsoids interacting via a Gaussian potential. According to the mean-field free-energy functional used here, our conclusions apply to soft-core potentials both when they form cluster crystals as the GEM-4 and when they form single-occupancy crystals as the Gaussian itself.
Weniger anzeigenWe have built and commissioned a novel standalone multi-crystal x-ray spectrometer (MOSARIX) in the von Hamos configuration based on highly annealed pyrolytic graphite crystals. The spectrometer is optimized for the energy range of 2–5 keV, but this range can be extended up to 20 keV by using higher reflection orders. With its nine crystals and a Pilatus detector, MOSARIX achieves exceptional detection efficiency with good resolving power (better than 4000), opening the door to study small cross section phenomena and perform fast in situ measurements. The spectrometer operates under a He atmosphere, which provides a flexible sample environment for measurements in gas, liquid, and solid phases.
Weniger anzeigenQuantum data access and quantum processing can make certain classically intractable learning tasks feasible. However, quantum capabilities will only be available to a select few in the near future. Thus, reliable schemes that allow classical clients to delegate learning to untrusted quantum servers are required to facilitate widespread access to quantum learning advantages. Building on a recently introduced framework of interactive proof systems for classical machine learning, we develop a framework for classical verification of quantum learning. We exhibit learning problems that a classical learner cannot efficiently solve on their own, but that they can efficiently and reliably solve when interacting with an untrusted quantum prover. Concretely, we consider the problems of agnostic learning parities and Fourier-sparse functions with respect to distributions with uniform input marginal. We propose a new quantum data access model that we call "mixture-of-superpositions" quantum examples, based on which we give efficient quantum learning algorithms for these tasks. Moreover, we prove that agnostic quantum parity and Fourier-sparse learning can be efficiently verified by a classical verifier with only random example or statistical query access. Finally, we showcase two general scenarios in learning and verification in which quantum mixture-of-superpositions examples do not lead to sample complexity improvements over classical data. Our results demonstrate that the potential power of quantum data for learning tasks, while not unlimited, can be utilized by classical agents through interaction with untrusted quantum entities.
Weniger anzeigenDer Beitrag untersucht explorativ das Adressierungsgeschehen in einem literaturwissenschaftlichen Seminar. Es zeigt sich, wie im Zusammenspiel der fachlichen Wissenspraxis des Interpretierens sowie der universitären Lehrpraxis des Seminars spezifische Subjektpositionen sowohl für die Studierenden als auch für den Dozierenden erzeugt werden. Während aus literaturdidaktischer Perspektive vor allem sichtbar wird, wie das Seminar das Einüben einer ästhetischen Haltung gegenüber dem Werk ermöglicht, wird aus Sicht einer rekonstruktiven Unterrichtsforschung eine spezifisch seminaristische Asymmetrie im Subjektverhältnis zwischen Studierenden und Dozierendem deutlich.
Weniger anzeigenDer vorliegende Policy Brief wurde im Rahmen des Verbundprojekts GeLeGanz erstellt, welches aus Mitteln des Bundesministeriums für Bildung und Forschung (BMBF) im Rahmen des Programms "Rahmenprogramm empirische Bildungsforschung" unter den Förderkennzeichen 01JB2112A-C gefördert wurde. In diesem Policy-Brief werden die zentralen Ergebnisse des Projekts zur Förderung sozial bildungsbenachteiligter Schüler:innen mit Migrationshintergrund in der offenen Ganztags(grund)schule dargelegt. Auf dieser Grundlage erfolgt die Aussprache von Empfehlungen für die Weiterentwicklung der pädagogischen Gestaltung der offenen Ganztags(grund)schule sowie deren außerunterrichtlichen Angebote.
Weniger anzeigenDie Versorgung sterbender und verstorbener Patient*innen sowie die fürsorgende Auseinandersetzung mit Angehörigen verlangt von Ärzt*innen hohe Sensibilität für fremde und eigene Empfindungen und Bedürfnisse. Doch inwiefern beeinflusst die Konfrontation mit dem Tod den ärztlichen Umgang mit dem eigenen Lebensende? Wie und in welchen (Text-)Formen werden Alter(n), Sterben und Tod imaginiert und narrativiert? Und welche Bezüge werden zwischen dem fremden und dem eigenen Leben(-sende) hergestellt? Die Beiträger*innen suchen anhand von fiktionalen und faktualen Quellen nach Antworten auf diese Fragen und erschließen im interdisziplinären Feld der Medical Humanities den Umgang von Mediziner*innen mit der eigenen Sterblichkeit.
Weniger anzeigenThis article examines the processes involved in materializing the past. The recording of archaeological objects plays a pivotal role in establishing artefacts as valuable data that can be categorized, classified, and analysed to turn into historical narratives. It contributes significantly to shaping our understanding of the past: while conveying information about the objects themselves, this documentation inherently captures the subjective context of its recording and continues to influence our interpretations. In this article, both objective details and subjective conceptions are analysed from the records (drawings, photographs, reports) made at the rock figure of Karabel (Turkey), a monumental bas-relief discovered by European explorers in the 1830s. The author uses Karabel's diverse and controversial interpretations to examine how knowledge and ideas about the past evolve. To counterbalance the conventional linear interpretation of the past, he offers some insights into non-academic aspects of the monument.
Weniger anzeigenSpecialized or secondary metabolites are small molecules of biological origin, often showing potent biological activities with applications in agriculture, engineering and medicine. Usually, the biosynthesis of these natural products is governed by sets of co-regulated and physically clustered genes known as biosynthetic gene clusters (BGCs). To share information about BGCs in a standardized and machine-readable way, the Minimum Information about a Biosynthetic Gene cluster (MIBiG) data standard and repository was initiated in 2015. Since its conception, MIBiG has been regularly updated to expand data coverage and remain up to date with innovations in natural product research. Here, we describe MIBiG version 4.0, an extensive update to the data repository and the underlying data standard. In a massive community annotation effort, 267 contributors performed 8304 edits, creating 557 new entries and modifying 590 existing entries, resulting in a new total of 3059 curated entries in MIBiG. Particular attention was paid to ensuring high data quality, with automated data validation using a newly developed custom submission portal prototype, paired with a novel peer-reviewing model. MIBiG 4.0 also takes steps towards a rolling release model and a broader involvement of the scientific community. MIBiG 4.0 is accessible online at https://mibig.secondarymetabolites.org/.
Weniger anzeigenThe AU Microscopii planetary system is only 24 Myr old, and its geometry may provide clues about the early dynamical history of planetary systems. Here, we present the first measurement of the Rossiter-McLaughlin effect for the warm sub-Neptune AU Mic c, using two transits observed simultaneously with the European Southern Observatory's (ESO's) Very Large Telescope (VLT)/Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO), CHaracterising ExOPlanet Satellite (CHEOPS), and Next-Generation Transit Survey (NGTS). After correcting for flares and for the magnetic activity of the host star, and accounting for transit-timing variations, we find the sky-projected spin-orbit angle of planet c to be in the range lambda(c) = 67.8(-49.0)(+31.7) degrees (1 sigma). We examine the possibility that planet c is misaligned with respect to the orbit of the inner planet b (lambda(b) = -2.96(-10.30)(+10.44)), and the equatorial plane of the host star, and discuss scenarios that could explain both this and the planet's high density, including secular interactions with other bodies in the system or a giant impact. We note that a significantly misaligned orbit for planet c is in some degree of tension with the dynamical stability of the system, and with the fact that we see both planets in transit, though these arguments alone do not preclude such an orbit. Further observations would be highly desirable to constrain the spin-orbit angle of planet c more precisely.
Weniger anzeigenContext. AU Mic is a very active M dwarf star with an edge-on debris disk and two known transiting sub-Neptunes with a possible third planetary companion. The two transiting planets exhibit significant transit-timing variations (TTVs) that are caused by the gravi tational interaction between the bodies in the system.
Aims. Using photometrical observations taken with the CHaracterizing ExOPlanet Satellite (CHEOPS), we aim to constrain the plan etary radii, the orbital distances, and the periods of AU Mic b and c. Furthermore, our goal is to determine the superperiod of the TTVs for AU Mic b and to update the transit ephemeris for both planets. Additionally, based on the perceived TTVs, we study the possible presence of a third planet in the system.
Methods. We conducted ultra-high precision photometric observations with CHEOPS in 2022 and 2023. We used Allesfitter to fit the planetary transits and to constrain the planetary and orbital parameters. We combined our new measurements with results from previous years to determine the periods and amplitudes of the TTVs. We applied dynamical modelling based on TTV measurements from the 2018–2023 period to reconstruct the perceived variations.
Results. We found that the orbital distances and periods for AU Mic b and c agree with the results from previous works. However, the values for the planetary radii deviate slightly from previous values, which we attribute to the effect of spots on the stellar surface. AU Mic c showed very strong TTVs, with transits that occurred ∼80 minutes later in 2023 than in 2021. Through a dynamical analysis of the system, we found that the observed TTVs can be explained by a third planet with an orbital period of ∼12.6 days and a mass of 0.203−0.024+0.022 M⊕. We explored the orbital geometry of the system and found that AU Mic c has a misaligned retrograde orbit. The limited number of AU Mic observations prevented us from determining the exact dynamical configuration and planetary parameters. Further monitoring of the system with CHEOPS might help to improve these results.
Weniger anzeigenWe present new observations from CHEOPS (CHaracterising ExOPlanet Satellite) and TESS (Transiting Exoplanet Survey Satellite) to clarify the architecture of the planetary system hosted by the old Galactic thick disc star TOI-561. Our global analysis, which also includes previously published photometric and radial velocity data, incontrovertibly proves that TOI-561 is hosting at least four transiting planets with periods of 0.44 d (TOI-561 b), 10.8 d (TOI-561 c), 25.7 d (TOI-561 d), and 77.1 d (TOI-561 e) and a fifth non-transiting candidate, TOI-561f with a period of 433 d. The precise characterization of TOI-561's orbital architecture is interesting since old and metal-poor thick disc stars are less likely to host ultrashort-period super-Earths like TOI-561 b. The new period of planet -e is consistent with the value obtained using radial velocity alone and is now known to be 77.14399 +/- 0.00025 d, thanks to the new CHEOPS and TESS transits. The new data allowed us to improve its radius (R-p = 2.517 +/- 0.045 R-circle plus from 5 per cent to 2 per cent precision) and mass (M-p = 12.4 +/- 1.4 M-circle plus) estimates, implying a density of rho(p) = 0.778 +/- 0.097 R-circle plus. Thanks to recent TESS observations and the focused CHEOPS visit of the transit of TOI-561 e, a good candidate for exomoon searches, the planet's period is finally constrained, allowing us to predict transit times through 2030 with 20-min accuracy. We present an updated version of the internal structure of the four transiting planets. We finally performed a detailed stability analysis, which confirmed the long-term stability of the outer planet TOI-561 f.
Weniger anzeigenAlthough the intraoperative molecular diagnosis of the approximately 100 known brain tumor entities described to date has been a goal of neuropathology for the past decade, achieving this within a clinically relevant timeframe of under 1 h after biopsy collection remains elusive. Advances in third-generation sequencing have brought this goal closer, but established machine learning techniques rely on computationally intensive methods, making them impractical for live diagnostic workflows in clinical applications. Here we present MethyLYZR, a naive Bayesian framework enabling fully tractable, live classification of cancer epigenomes. For evaluation, we used nanopore sequencing to classify over 200 brain tumor samples, including 10 sequenced in a clinical setting next to the operating room, achieving highly accurate results within 15 min of sequencing. MethyLYZR can be run in parallel with an ongoing nanopore experiment with negligible computational overhead. Therefore, the only limiting factors for even faster time to results are DNA extraction time and the nanopore sequencer’s maximum parallel throughput. Although more evidence from prospective studies is needed, our study suggests the potential applicability of MethyLYZR for live molecular classification of nervous system malignancies using nanopore sequencing not only for the neurosurgical intraoperative use case but also for other oncologic indications and the classification of tumors from cell-free DNA in liquid biopsies.
Weniger anzeigenMicrobial carbon use efficiency (CUE) is a key microbial trait affecting soil organic carbon (SOC) dynamics. However, we lack a unified and predictive understanding of the mechanisms underpinning the temperature response of microbial CUE, and, thus, its impacts on SOC storage in a warming world. Here, we leverage three independent soil datasets (n = 618 for microbial CUE; n = 591 and 660 for heterotrophic respiration) at broad spatial scales to investigate the microbial thermal response and its implications for SOC responses to warming. We show a nonlinear increase and decrease of CUE and heterotrophic respiration, respectively, in response to mean annual temperature (MAT), with a thermal threshold at ≈15 °C. These nonlinear relationships are mainly associated with changes in the fungal-to-bacterial biomass ratio. Our microbial-explicit SOC model predicts significant SOC losses at MAT above ≈15 °C due to increased CUE, total microbial biomass, and heterotrophic respiration, implying a potential abrupt transition to more vulnerable SOC under climate warming.
Weniger anzeigenRed teaming, the practice of adversarially exposing unexpected or undesired model behaviors, is critical towards improving equity and accuracy of large language models, but non-model creator-affiliated red teaming is scant in healthcare. We convened teams of clinicians, medical and engineering students, and technical professionals (80 participants total) to stress-test models with real-world clinical cases and categorize inappropriate responses along axes of safety, privacy, hallucinations/accuracy, and bias. Six medically-trained reviewers re-analyzed prompt-response pairs and added qualitative annotations. Of 376 unique prompts (1504 responses), 20.1% were inappropriate (GPT-3.5: 25.8%; GPT-4.0: 16%; GPT-4.0 with Internet: 17.8%). Subsequently, we show the utility of our benchmark by testing GPT-4o, a model released after our event (20.4% inappropriate). 21.5% of responses appropriate with GPT-3.5 were inappropriate in updated models. We share insights for constructing red teaming prompts, and present our benchmark for iterative model assessments.
Weniger anzeigenArbuscular mycorrhizal (AM) fungi (phylum Glomeromycota) are obligate symbionts with plants influencing plant health, soil a(biotic) processes, and ecosystem functioning. Despite advancements in molecular techniques, understanding the role of AM fungal communities on a(biotic) processes based on AM fungal taxonomy remains challenging. This review advocates for a standardized trait-based framework to elucidate the life-history traits of AM fungi, focusing on their roles in three dimensions: host plants, soil, and AM fungal ecology. We define morphological, physiological, and genetic key traits, explore their functional roles and propose methodologies for their consistent measurement, enabling cross-study comparisons towards improved predictability of ecological function. We aim for this review to lay the groundwork for establishing a baseline of AM fungal trait responses under varying environmental conditions. Furthermore, we emphasize the need to include underrepresented taxa in research and utilize advances in machine learning and microphotography for data standardization.
Weniger anzeigenEste libro recorre la historia de la Policía, el delito y los delincuentes en Colombia entre mediados del siglo XIX y principios del XX. A través del estudio de las ciencias policiales y sus sistemas de identificación criminal – la antropometría y la fotografía – se analizan las complejas relaciones entre el Estado y la sociedad; los cuerpos de vigilancia y la criminalidad urbana y rural; los saberes globales y locales; las conexiones entre arte y ciencia, así como los conflictos urbanos, electorales e intelectuales de la época. El texto se enfoca en el proceso de circulación global y apropiación local de la antropometría criminal, conocida como Bertillonage, dentro de la Policía Nacional como parte de su agenda reformista a inicios del siglo XX. Este período fue clave en la consolidación de la antropometría como una herramienta fundamental para el mantenimiento del orden social, gracias a su capacidad de individualizar reincidentes y fortalecer la operatividad policial. Este proceso no exento de resistencias. Cuadrillas de malhechores, revueltas artesanales y obreras, insurrecciones populares, atentados, magnicidios, hurtos, prostitución, apuñalamientos y la llegada de criminales internacionales no solo evidencian la evolución paralela y dialéctica del delito y de los saberes policiales, sino que también reflejan las resistencias “desde abajo” a las prácticas de vigilancia e identificación. Estas manifestaciones permiten una lectura más allá de los discursos oficiales, tradicionalmente centrados en la efectividad y el control social. Desde una perspectiva subalterna, el libro examina los efectos de las ciencias policiales sobre el honor y la identidad de quienes fueron sometidos a sus métodos de identificación, revelando las tensiones entre seguridad, control y derechos individuales.
Weniger anzeigenGegenstand des Forschungsprojektes war die Präsenz der theologischen Philosophie und der philosophischen Theologie im patristischen Denken (Ost und West). Die patristischen Testimonien zum Corpus Hermeticum wurden in diesem Kontext erstmalig umfassend erforscht. Die systematische Analyse erstreckte sich auf folgende Autoren: Athenagoras von Athen, Clemens von Alexandria, Origenes von Alexandria, Firmianus Lactantius, Didymos von Alexandria (einschl. Pseudo-Didymos), Synesios von Kyrene und Kyrill von Alexandria. Die Auswertung der übrigen patristischen Testimonien über Hermes Trismegistos brachte eine Reihe weiterer neuer Ergebnisse zutage. Das Forschungsprojekt zeigte die wesentliche Teilhabe des Christentums an der kaiserzeitlichen Pluralisierung des Philosophiebegriffs am Beispiel der patristischen Auseinandersetzung mit den zwei genannten Denkformen auf. Durch das Forschungsprojekt ist die Wirkungsgeschichte des Corpus Hermeticum in der patristischen Tradition grundlegend aufgehellt worden.
Weniger anzeigenErgothioneine (ET), a dietary thione/thiol, is receiving growing attention for its possible benefits in healthy aging and metabolic resilience. Our study investigates ET’s effects on healthspan in aged animals, revealing lifespan extension and enhanced mobility in Caenorhabditis elegans, accompanied by improved stress resistance and reduced age-associated biomarkers. In aged rats, ET administration enhances exercise endurance, muscle mass, and vascularization, concomitant with higher NAD+ levels in muscle. Mechanistically, ET acts as an alternative substrate for cystathionine gamma-lyase (CSE), stimulating H2S production, which increases protein persulfidation of more than 300 protein targets. Among these, protein-persulfidation-driven activation of cytosolic glycerol-3-phosphate dehydrogenase (cGPDH) primarily contributes to the ET-induced NAD+ increase. ET’s effects are abolished in models lacking CSE or cGPDH, highlighting the essential role of H2S signaling and protein persulfidation. These findings elucidate ET’s multifaceted actions and provide insights into its therapeutic potential for combating age-related muscle decline and metabolic perturbations.
Weniger anzeigenThe effects of atmospheric aerosols are key uncertainties in climate models. One reason is the complex aerosol composition which includes a relatively large fraction of organics. Another reason is the small size of aerosols, which makes surface effects and processes important. These two factors make surface-active organics relevant for atmospheric aerosols, as they can affect crucial processes, such as chemical aging and water accommodation, as well as properties such as the surface tension, which drives droplet formation. Two exemplary types of atmospherically relevant organics are carboxylic acids and alkyl amines, and often both are found together within aerosols. In the most atmospherically significant pH range, these exist as alkyl-carboxylate ions and alkyl-ammonium ions. Using liquid-jet photoelectron spectroscopy, tuned to high surface sensitivity, we measured the alkyl-carboxylate anions and the alkyl-ammonium cations of alkyl chain lengths of 1 to 6 carbon atoms, both as single-component and mixed-component aqueous solutions. This enabled us to systematically study how their surface propensity is affected by the length of the alkyl chains and how cooperative ion–ion interactions result in strongly increased surface propensity. An exponential increase in surface propensity is found for the single-species solutions, with cooperative solute–solute effects in mixed solutions of 1 : 1 molar ratio drastically increasing the number of molecules present at the solutions' surfaces up to a factor of several hundred. This cooperative surface propensity is shown to strongly affect the amounts of organics at the surface. These changes can significantly influence radiative forcing via aerosol growth, cloud condensation nuclei activity, and aerosol chemical aging. Our results demonstrate the principal feasibility of a more advanced input of molecular details for creating parameterized descriptions of aerosol surface composition needed to properly account for their impacts in climate models.
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