Aktuelle Publikationen

Image-guided drawing can compensate for a lack of skill but often requires a significant number of repetitive strokes to create textures. Existing automatic stroke synthesis methods are usually limited to predefined styles or require indirect manipulation that may break the spontaneous flow of drawing. We present an assisted drawing system to autocomplete repetitive short strokes during a user’s normal drawing process. Users draw over a reference image as usual; at the same time, our system silently analyzes the input strokes and the reference to infer strokes that follow the user’s input style when certain repetition is detected. Users can accept, modify, or ignore the system’s predictions and continue drawing, thus maintaining fluid control over drawing. Our key idea is to jointly analyze image regions and user input history to detect and predict repetition. The proposed system can effectively reduce the user’s workload when drawing repetitive short strokes, helping users to create results with rich patterns.

The understanding of friction at nano-scales, ruled by the regular arrangement of atoms, is surprisingly incomplete. Here we provide a unified understanding by studying the interlocking potential energy of two infinite contacting surfaces with arbitrary lattice symmetries, and extending it to finite contacts. We categorize, based purely on geometrical features, all possible contacts into three different types: a structurally lubric contact where the monolayer can move isotropically without friction, a corrugated and strongly interlocked contact, and a newly discovered directionally structurally lubric contact where the layer can move frictionlessly along one specific direction and retains finite friction along all other directions. This novel category is energetically stable against rotational perturbations and provides extreme friction anisotropy. The finite-size analysis shows that our categorization applies to a wide range of technologically relevant materials in contact, from adsorbates on crystal surfaces to layered two-dimensional materials and colloidal monolayers.

While the multiple barriers women face to attain public office have been vastly documented, the operation of insider/outsider dynamics within political parties’ top decision-making bodies remains largely under-researched. This article provides new theoretical and empirical insights on how interpersonal resources create ingroups and outgroups in parties’ national executive committees—the body that manages the day-to-day functioning of the extra-parliamentary party organization. Our comparative analysis of Spanish political parties in the period 1975–2020 documents that interpersonal resources are unevenly distributed across gender. Most crucially, we show that these resources play out differently for women and men members, with embeddedness in party networks only helping the latter attain positional power and extend their tenure in party office. These heterogeneous effects suggest that top decision-making party bodies do not just reflect existing gender inequalities but reinforce them in significant ways, rendering women member outsiders on the inside.

Recently, there has been a growing concern with the (non-)replicability of scientific findings. Many reasons for the ‘replication crisis’ have been brought forward, including uncorrected multiple-hypotheses testing, ex-post theorising, p-hacking, publication bias, and under-powered studies (see, for example, the excellent discussion in Renkewitz & Keiner, 2019). Four years ago, Experimental Economics called for proposals to be reviewed before collecting data. The aim was to gain experience with this new form of organising the research process that has been gaining popularity in many other disciplines over the past decade.

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dc.contributor.author: Djärv, Kajsa

Understanding the fundamental physicochemical processes that occur during the hydration of cementitious materials is essential for developing alternative binders that enable the partial substitution of Portland cement (PC), lowering the carbon footprint associated with the cement industry. Magnesium-silicate-hydrate (M-S-H) stands as a potential alternative binder; however, its inferior mechanical properties attributed to its nanostructure, and the high-water demand for curing, hinder the application of MgO-based cement as PC surrogate. A potential strategy to tackle these major drawbacks is based on controlling M-S-H formation from the early stages, building the properties and nanostructure of this binding phase from its basic building units. The present work provides insights into M-S-H nucleation and early growth gathered by combining titration experiments with electrospray ionization mass spectrometry, analytical ultracentrifugation, and transmission electron microscopy. We evidenced a nonclassical multistep pathway where a highly complex mixture of defined hydrated magnesium (sodium)-silicate oligomeric species exists in solution prior nucleation. Our results suggest that these entities aggregate, yielding an ill-defined M-S-H precursor phase (depleted in Mg compared to the final product) which later transforms into a denser M-S-H interconnected network (Mg:Si ratio ca. 1) with a more defined sheet-like structure that still retains its poorly crystalline character. The identification of oligomeric silicates species prior nucleation is of great importance for developing means to regulate M-S-H (and potentially other hydrous silicates) formation by using a bottom-up approach. This work reveals that, during the hydration process of cementitious materials, the stages prior to the formation of hydrated solids cannot be disregarded, as they could open new avenues for engineering the properties of the final materials.

Communication constraints often complicate group decision-making. In this experiment, we investigate how the network position of opinionated group members determines both the speed and the outcome of group consensus in 7-member communication networks susceptible to polarization. To this end, we implemented an online version of a color coordination task within experimentally controlled communication networks. In 72 networks, one individual was incentivized to prefer one of two options. In 156 networks, two individuals were incentivized to prefer conflicting options. The network positions of incentivized individuals were varied. In networks with a single incentivized individual, network position played no significant role in either the speed or outcome of consensus decisions. For conflicts, the incentivized individual with more neighbors was more likely to sway the group to their preferred outcome. Furthermore, consensus emerged more slowly when the opponents had the same number of neighbors, but could not see each other’s votes directly. These results suggest that the visibility of an opinion is key to wielding group influence, and that specific structures are sufficient to run communication networks into polarization, hindering a speedy consensus.

The scattering picture of electron transport in mesoscopic conductors shows that fluctuations of the current reveal additional information on the scattering mechanism not available through the conductance alone. The electronic fluctuations are coupled to the electromagnetic field and a junction at finite bias or temperature will emit radiation. The nonsymmetrized current-current correlators characterize the emission and absorption spectrum. Recent interest is focused on the so-called delta-T noise, which is the nonequilibrium noise caused by a temperature difference between the terminals. Here, we generalize the notion of delta-T noise to the nonsymmetrized current-current correlator at finite frequencies. We investigate the spectral density for energy-independent scattering and for a resonant level as an example of energy-dependent scattering. We find that a temperature difference ΔT leads to a partial reduction of the noise for certain frequency ranges. This is a consequence of temperature broadening in combination with a frequency shift of the involved Fermi distributions. In the case of energy-independent scattering, the lowest order is a quadratic ∝(ΔT)2 correction of the thermal-like noise spectrum. For the resonance, additional contributions to the delta-T noise spectrum arise that are ∝ΔT to the lowest order.

BACKGROUND: Castration-resistant prostate cancer (CRPC) is refractory to hormone treatment. This study aims to explore the effect and underlying mechanisms of immunoproteasome inhibition, a novel immunotherapy, on the progression of CRPC.

METHODS: The immunoproteasome subunit LMP7 was silenced by using gene knockout or inhibited by the epoxyketone inhibitor ONX 0914 in a mouse CRPC tumour graft model and in interferon-γ-pretreated human CRPC cell lines in vitro.

RESULTS: CRPC tissues reveal a significant “tumour-elicited” Th17-type inflammatory response which induces immunoproteasome subunit expression. LMP7 deficiency in host mice or in CRPC tumour grafts had no effect on the “tumour-elicited” Th17-type inflammatory response and tumour progression. However, the selective LMP7 inhibitor ONX 0914 strongly suppressed the “tumourelicited” Th17-type inflammatory response and CRPC tumour progression. Treatment of wild-type mice receiving LMP7-deficient CRPC tumour grafts with ONX 0914 further suggested that immunoproteasome inhibition prevents CRPC progression through suppressing IL-17-induced angiogenesis and epithelial–mesenchymal transition via inactivation of COX-2/VEGF-A signalling and β-catenin/Snail signalling. Treatment of LMP7-deficient mice receiving wild-type CRPC tumour grafts with ONX 0914 and inhibition of LMP7 in PC3 and 22Rv.1 cells with ONX 0914 showed that immunoproteasome inhibition also prevents CRPC progression through inducing CRPC cell apoptosis via activation of the unfolded protein response.

CONCLUSIONS: We define a critical role of the immunoproteasome in CRPC and propose immunoproteasome inhibition as a promising therapeutic approach to suppress CRPC progression.

We evaluate the performance of small error-correcting codes, which we tailor to hardware platforms of very different connectivity and coherence: on a superconducting processor based on transmon qubits and a spintronic quantum register consisting of a nitrogen-vacancy center in diamond. Taking the hardware-specific errors and connectivity into account, we investigate the dependence of the resulting logical error rate on the platform features such as the native gates, native connectivity, gate times, and coherence times. Using a standard error model parameterized for the given hardware, we simulate the performance and benchmark these predictions with experimental results when running the code on the superconducting quantum device. The results indicate that for small codes, the quasi-linear layout of the superconducting device is advantageous. Yet, for codes involving multi-qubit controlled operations, the central-spin connectivity of the color centers enables lower error rates.

World-wide declines in arthropod abundance and diversity are a major concern, particularly given their importance in ecosystem functioning. Yet, data documenting long-term trends are rare from the tropics, particularly the Afrotropics. Here we evaluate changes in the arthropod communities in Kibale National Park, Uganda across almost four decades. Systematic sweep-net sampling was conducted in two forested sections of the park that had been logged and in one old-growth forest area over 12 consecutive months in 1983/1984 and 2020/2021. This data was augmented with intermittent samples taken in 1986 and 1995. Arthropod abundance declined in all areas, but only significantly so in the moderately logged forestry compartment (41%). Permutational multivariate analysis of variance indicated that community compositions of arthropods differed between the censuses. Understanding the drivers of changes in the arthropod communities is difficult as the system is complex and dynamic. We document an increase in temperature, but no change in rainfall, increases in 11 mammal species, including a marked increase in elephant numbers, and changes in forest structure. We also report on changes in the landscape outside of the park, which includes the human population increasing by a factor of four and agricultural intensification that now includes the use of pesticides. We document that many components of the ecosystem we studied changed simultaneously, which signals that for effective conservation planning, more long-term multi-disciplinary efforts are needed.

This viewpoint discusses how interdisciplinary assessment methods of person-place benefits the socio-ecological perspective in urban health research. It starts with an overview on previous findings, which address relationships of environmental features to physical activity and mental health outcomes. We emphasize the need for appropriate approaches to assess time-sensitive associations to adequately investigate person-place interactions. Finally, we focus on ambulatory assessments and conclude that they can be improved by using a triggered design to capture data in situations where a strong contextual effect is assumed and by combining data and knowledge from different disciplines.

We give an overview of the methodological possibilities of some important digital tools for teaching philosophy. Several didactically applicable methods have evolved in digital culture, including their implicit methodologies, theories about how these methods may be used. These methodologies are already applied by philosophers today and have their benefits and justifications in philosophy classes as well. They can help to solve known problems of philosophy education. We discuss problems of incomprehensibility and their possible solutions through digital explanations in pod- and videocasts such as YouTube; problems of interaction, motivation, and immersion that digital games and gamification may solve; problems of the complexity of philosophical content and digital concept- and argument-maps to deal with these; problems of implicitness and the possibility to make implicit things in philosophy class explicit through indirect feedback tools.