814 research outputs found
<i>Baltorussus</i> total makeover:rejuvenation and sex change in an ancient parasitoid wasp lineage
The Orussidae is a small and rare but phylogenetically important family of parasitoid wasps. The fossil record of the family is also very poor. Baltorussus velteni was described from Baltic amber from an allegedly female specimen. This and another recently discovered specimen are examined with microCT scanning and standard microscopy. We reveal that both the holotype and the new specimen are actually males. Furthermore, the results of the microCT scanning allow us to integrate the fossils in a morphological data set assembled for extant Orussidae. Phylogenetic analyses consistently retrieve Baltorussus as a separate basal lineage within the crown group, whereas two Cretaceous fossils are placed as stem group orussids and a Dominican amber fossil in an extant genus. Based on the positions of the fossils, we estimate that the extant Orussidae radiated in the mid-Cretaceous (approx. 100 Ma ago). This is considerably younger than a previously suggested Early Jurassic date (180 Ma ago), which was primarily based on biogeographic evidence
Zusammenarbeit unter Unbekannten
Wie wird eine Kreislaufwirtschaft möglich? Mehr Techniken der Zusammenarbeit mit Unbekannten sind dafĂŒr notwendig. Dazu gehören der Einsatz von Standards, vollstĂ€ndige RecyclingfĂ€higkeit und Open Source. Open Source sorgt fĂŒr um fassende Transparenz, einen freien Zugang zur Information und fĂŒr alle offenliegende LösungsansĂ€tze
Federalism, Decentralization, and Economic Growth
The distribution of competencies between the different levels of a federal system may have remarkable effects on economic growth, because mainly the regions of a country contribute to national economic development. Thus, a governmentâs economic policy is reasonably shaped along regional lines. The theoretical discussion in economics focuses however on the efficiency aspects of a decentralized provision and financing of public services; rarely the argument is raised that decentralization or federalism increases growth through a higher ability of the political system to innovate and to carry out reforms. After a discussion of the theoretical arguments on federalism and growth, we address the empirical question in this paper how important the assignment of decision making competencies and the design of fiscal federalism are for economic development. Finally, on the basis of existing theoretical and empirical studies on economic growth and federalism, open questions and possible ways of answering them are presented.
The importance of teacher-student relationships in classrooms with âdifficultâ students: a multi-level moderation analysis of nine Berlin secondary schools
Meta-analyses suggest that instructional quality in the classroom and the quality of teacher-student relationships (TSR) predict positive social-emotional and achievement-related outcomes. Psychoanalytic theory asserts that positive teacher-student relationships are particularly important for outcomes in classrooms with more students with severe psychosocial difficulties. Hence, this study tests whether classrooms with more students with severe psychosocial difficulties have better social-emotional and achievement-related outcomes when teachers have been able to establish more positive relationships with their students. Hierarchical linear regression models use nested student survey data from 32 classrooms. Results only partially support the hypothesis and suggest that too many students with psychosocial difficulties might overwhelm even teachers with strong relationship-building skills, leading to detrimental outcomes.Peer Reviewe
Towards reliable parameter extraction in MEMS final module testing using Bayesian inference
In micro-electro-mechanical systems (MEMS) testing high overall precision and reliability are essential. Due to the additional requirement of runtime efficiency, machine learning methods have been investigated in recent years. However, these methods are often associated with inherent challenges concerning uncertainty quantification and guarantees of reliability. The goal of this paper is therefore to present a new machine learning approach in MEMS testing based on Bayesian inference to determine whether the estimation is trustworthy. The overall predictive performance as well as the uncertainty quantification are evaluated with four methods: Bayesian neural network, mixture density network, probabilistic Bayesian neural network and BayesFlow. They are investigated under the variation in training set size, different additive noise levels, and an out-of-distribution condition, namely the variation in the damping factor of the MEMS device. Furthermore, epistemic and aleatoric uncertainties are evaluated and discussed to encourage thorough inspection of models before deployment striving for reliable and efficient parameter estimation during final module testing of MEMS devices. BayesFlow consistently outperformed the other methods in terms of the predictive performance. As the probabilistic Bayesian neural network enables the distinction between epistemic and aleatoric uncertainty, their share of the total uncertainty has been intensively studied
Wie LehrkrĂ€fte psychosozial beeintrĂ€chtigter SchĂŒler:innen den Berufseinstieg meistern können. Eine tiefenhermeneutische Fallanalyse
Die Berufseinstiegsphase ist fĂŒr LehrkrĂ€fte eine besonders groĂe Herausforderung. Ziel dieser Studie ist es, Hinweise dafĂŒr zu finden, wie eine Lehrkraft ihre Berufseinstiegsphase erfolgreich meistern kann. Zu diesem Zweck wurde das Interview mit einer jungen Berufseinsteigerin, deren SchĂŒler:innen ihre Beziehungs- und Unterrichtskompetenzen ĂŒberdurchschnittlich positiv einschĂ€tzten, tiefenhermeneutisch ausgewertet. Die Ergebnisse zeigen, wie schwierige Fragen von AutoritĂ€t, NĂ€he und Distanz, und persönlicher Verletzbarkeit fĂŒr eine Lehrkraft und fĂŒr Lehramtsstudierende, die in die Auswertungsphase der Studie eingebunden wurden, eine wirkmĂ€chtige Rolle spielen. (DIPF/Orig.
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Design and performance analysis of integrated focusing grating couplers for the transverse-magnetic TM00 mode in a photonic BiCMOS technology
Focusing grating couplers for the excitation of the fundamental transverse-magnetic (TM) mode in integrated silicon photonic waveguides are designed and characterized under the boundary conditions of a photonic BiCMOS foundry. Two types of waveguide geometries are considered â a nanowire and a rib waveguide. Wafer-scale experimental results for nanowire TM grating couplers are in excellent agreement with numerical investigations and demonstrate a robust behavior on the wafer. The mean coupling loss and the 3s interval are -3.9 ± 0.3 dB. The on wafer variation is three times lower than for the fundamental transverse-electric (TE) polarization. Similarly, the coupling in rib waveguides is examined as well. The results indicate that the rib waveguides require a modified geometry when designed for TM. In general, the nanowire waveguide type is more suitable for TM coupling, showing a stable and repeatable performance. © 2020, The Author(s)
Design and performance analysis of integrated focusing grating couplers for the transverse-magnetic TM00 mode in a photonic BiCMOS technology
Focusing grating couplers for the excitation of the fundamental transverse-magnetic (TM) mode in integrated silicon photonic waveguides are designed and characterized under the boundary conditions of a photonic BiCMOS foundry. Two types of waveguide geometries are considered â a nanowire and a rib waveguide. Wafer-scale experimental results for nanowire TM grating couplers are in excellent agreement with numerical investigations and demonstrate a robust behavior on the wafer. The mean coupling loss and the 3Ï interval are -3.9â±â0.3âdB. The on wafer variation is three times lower than for the fundamental transverse-electric (TE) polarization. Similarly, the coupling in rib waveguides is examined as well. The results indicate that the rib waveguides require a modified geometry when designed for TM. In general, the nanowire waveguide type is more suitable for TM coupling, showing a stable and repeatable performance.DFG, 414044773, Open Access Publizieren 2019 - 2020 / Technische UniversitĂ€t Berli
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Modulation Linearity Characterization of Si Ring Modulators
Modulation linearity of Si ring modulators (RMs) is investigated through the numerical simulation based on the coupled-mode theory and experimental verification. Numerical values of the key parameters needed for the simulation are experimentally extracted. Simulation and measurement results agree well. With these, the influence of input optical wavelength and power on the Si RM linearity are characterized
Whispering Gallery Modes-based biosensors for real-time monitoring and binding characterization of antibody-based cancer immunotherapeutics
Development of novel protein-based drugs such as antibodies or immunocytokines and initial validation of target binding typically occurs in 2D settings with e.g., surface plasmon resonance or reflection interferometry using antigen-coated planar sensors. However, a versatile tool to assess binding characteristics of tumour-targeting therapeutics where specific biochemical interactions can be monitored in real-time and in a more realistic 3D interaction setting is currently lacking. Here, we report on the development of versatile small optical 3D biosensors using protein G-coated spherical microparticles based on Whispering Gallery Modes (WGMs). These sensors allowed for an oriented immobilization of theoretically any immunoglobulin G (IgG) and IgG crystallizable fragment domain (Fc)-tagged protein and have been carefully optimized for specific detection of antigenantibody interactions, as illustrated using the Epithelial Growth Factor Receptor (EGFR) antibody Cetuximab and Program Death Ligand 1 (PD-L1) antibody Atezolizumab. When both ligand and analyte contained an Fcfragment, protein G binding capacity saturation followed by a "blocking" step with an irrelevant IgG enabled the label-free detection of Fc-tagged antigens with corresponding cognate ligands, as identified using EGFR-Fc, PD-L1-Fc and different members from the tumour necrosis factor receptor family, such as CD27-Fc and 4- 1BBFc. Thus, WGMs and developed protein G-coated biosensors provide a widely applicable tool to evaluate binding of immunotherapeutics to their targets on the sensor surface, imitating cell surface properties
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