Search

Traditional research on political parties pays little attention to the temporal focus of communication. It usually concentrates on promises, issue attention, and policy positions. This lack of scholarly attention is surprising, given that voters respond to nostalgic rhetoric and may even adjust issue positions when policy is framed in nostalgic terms. This article presents a novel dataset, PolNos, which contains six text-based measures of nostalgic rhetoric in 1,648 party manifestos across 24 European democracies from 1946 to 2018. The measures combine dictionaries, word embeddings, sentiment approaches, and supervised machine learning. Our analysis yields a consistent result: nostalgia is most prevalent in manifestos of culturally conservative parties, notably Christian democratic, nationalist, and radical right parties. However, substantial variation remains regarding regional differences and whether nostalgia concerns the economy or culture. We discuss the implications and use of our dataset for studying political parties, party competition, and elections. [ABSTRACT FROM AUTHOR]

Do private interests predict politicians' rhetoric? Focusing on housing policy, we compare issue emphasis and positions of landlord politicians and politicians who do not own multiple properties. Ireland provides a unique opportunity to study legislating landlords' behavior as housing has become one of the most important political issues. We construct a novel dataset of politicians' homeownership status between 2013 and 2022, a period characterized by rising rent and property prices. We fine‐tune a transformer‐based machine learning model and apply text scaling and sentiment analysis to identify issue salience and positions on housing in over 870,000 tweets and parliamentary questions. Contrary to our expectations, landlord politicians do not avoid the topic of housing, nor do they take different positions. We also find that government status does not influence this relationship. The results imply that private financial interests do not influence rhetoric on housing policy. [ABSTRACT FROM AUTHOR]

Ribosomes are key to cellular self-fabrication and limit growth rate. While most enzymes are proteins, ribosomes consist of 1/3 protein and 2/3 ribonucleic acid (RNA) (in E. coli). Here, we develop a mechanistic model of a self-fabricating cell, validated across diverse growth conditions. Through resource balance analysis (RBA), we explore the variation in maximum growth rate with ribosome composition, assuming constant kinetic parameters. Our model highlights the importance of RNA instability. If we neglect it, RNA synthesis is always cheaper than protein synthesis, leading to an RNA-only ribosome at maximum growth rate. Upon accounting for RNA turnover, we find that a mixed ribosome composed of RNA and proteins maximizes growth rate. To account for RNA turnover, we explore two scenarios regarding the activity of RNases. In (a) degradation is proportional to RNA content. In (b) ribosomal proteins cooperatively mitigate RNA instability by protecting it from misfolding and subsequent degradation. In both cases, higher protein content elevates protein synthesis costs and simultaneously lowers RNA turnover expenses, resulting in mixed RNA-protein ribosomes. Only scenario (b) aligns qualitatively with experimental data across varied growth conditions. Our research provides fresh insights into ribosome biogenesis and evolution, paving the way for understanding protein-rich ribosomes in archaea and mitochondria. Mechanistic modeling (resource balance analysis) links ribosome composition to growth rate. Only if the costs of ribosomal RNA stabilization are taken into account, maximum growth occurs for a mixed (RNA+protein) ribosome, as observed experimentally. [ABSTRACT FROM AUTHOR]

Generalized mass-action systems are power-law dynamical systems arising from chemical reaction networks. Essentially, every nonnegative ODE model used in chemistry and biology (for example, in ecology and epidemiology) and even in economics and engineering can be written in this form. Previous results have focused on existence and uniqueness of special steady states (complex-balanced equilibria) for all rate constants, thereby ruling out multiple (special) steady states. Recently, necessary conditions for linear stability have been obtained. In this work, we provide sufficient conditions for the linear stability of complex-balanced equilibria for all rate constants (and also for the nonexistence of other steady states). In particular, via sign vector conditions (on the stoichiometric coefficients and kinetic orders), we guarantee that the Jacobian matrix is a P-matrix. Technically, we use a new decomposition of the graph Laplacian which allows us to consider orders of (generalized) monomials. Alternatively, we use cycle decomposition which allows a linear parametrization of all Jacobian matrices. In any case, we guarantee stability without explicit computation of steady states. We illustrate our results in examples from chemistry and biology: generalized Lotka--Volterra systems and SIR models, a two-component signaling system, and an enzymatic futile cycle. [ABSTRACT FROM AUTHOR]

Many citizens support the involvement of experts in political decision-making, yet we know little about how citizens react to expert opinions. Bridging recent evidence on technocratic attitudes and deliberative democracy, we study citizen responses to experts during influential deliberative mini-publics. Combining automated speech transcription of over 380,000 spoken words and quantitative text analysis, we estimate the topic prevalence in all expert testimonials, Q&A sessions, and other agenda items in the Irish Citizens' Assembly (2016–2018), one of the prime examples of impactful deliberative forums. We find that inputs of experts structure subsequent discussions but do not dominate them. This correlation persists with various measures of topic prevalence and is robust to several modelling approaches. We also find that participants tended to react less strongly to testimonials by female experts. These conditional effects should encourage organisers to invite experts with diverse backgrounds in order to enhance inclusive decision-making. [ABSTRACT FROM AUTHOR]

We provide a new decomposition of the Laplacian matrix (for labeled directed graphs with strongly connected components), involving an invertible core matrix, the vector of tree constants, and the incidence matrix of an auxiliary graph, representing an order on the vertices. Depending on the particular order, the core matrix has additional properties. Our results are graph-theoretic/algebraic in nature. As a first application, we further clarify the binomial structure of (weakly reversible) mass-action systems, arising from chemical reaction networks. Second, we extend a classical result by Horn and Jackson on the asymptotic stability of special steady states (complex-balanced equilibria). Here, the new decomposition of the graph Laplacian allows us to consider regions in the positive orthant with given monomial evaluation orders (and corresponding polyhedral cones in logarithmic coordinates). As it turns out, all dynamical systems are asymptotically stable that can be embedded in certain binomial differential inclusions. In particular, this holds for complex-balanced mass-action systems, and hence, we also obtain a polyhedral-geometry proof of the classical result. [ABSTRACT FROM AUTHOR]

Precipitation patterns are commonly concentric rings forming in a Petri dish or parallel bands appearing in a test tube (Liesegang phenomenon). The rings frequently consist of a number of convex segments that are separated from each other by spaces devoid of precipitate resulting in small gaps (dislocations). Along these gaps, the so-called zig-zag structures can form, which connect one side of a gap with its opposite side. We observe that the occurrence of zig-zags requires a minimum thickness of the reactive layer (≥ 0.8 mm). This fact together with microscopic evidence indicates their three-dimensional character. One finds that at the very beginning of the precipitation reaction a curling process starts in the corresponding contour lines. These observations suggest structures of a helicoid with the axis perpendicular to the plane of the reaction–diffusion front to pass through the layer. Zig-zags are not parallel to the reaction plane, i.e., they are not formed periodically, but evolve continuously as a rotating spiral wave. Thus, their topology is closely related to helices in a test tube. [ABSTRACT FROM AUTHOR]

Background: The Western mosquitofish, Gambusia affinis, is a model for sex chromosome organization and evolution of female heterogamety. We previously identified a G. affinis female-specific marker, orthologous to the aminomethyl transferase (amt) gene of the related platyfish (Xiphophorus maculatus). Here, we have analyzed the structure and differentiation of the G. affinis W-chromosome, using a cytogenomics and bioinformatics approach. Results: The long arm of the G. affinis W-chromosome (Wq) is highly enriched in dispersed repetitive sequences, but neither heterochromatic nor epigenetically silenced by hypermethylation. In line with this, Wq sequences are highly transcribed, including an active nucleolus organizing region (NOR). Female-specific SNPs and evolutionary young transposable elements were highly enriched and dispersed along the W-chromosome long arm, suggesting constrained recombination. Wq copy number expanded elements also include female-specific transcribed sequences from the amt locus with homology to TE. Collectively, the G. affinis W-chromosome is actively differentiating by sex-specific copy number expansion of transcribed TE-related elements, but not (yet) by extensive sequence divergence or gene decay. Conclusions: The G. affinis W-chromosome exhibits characteristic genomic properties of an evolutionary young sex chromosome. Strikingly, the observed sex-specific changes in the genomic landscape are confined to the W long arm, which is separated from the rest of the W-chromosome by a neocentromere acquired during sex chromosome evolution and may thus have become functionally insulated. In contrast, W short arm sequences were apparently shielded from repeat-driven differentiation, retained Z-chromosome like genomic features, and may have preserved pseudo-autosomal properties. [ABSTRACT FROM AUTHOR]

The influence of short‐time heat treatment on the widely used and commercially available ledeburitic cold‐work tool steel 1.2379 (X153CrMoV12; AISI D2) is examined herein. Starting from a soft annealed initial condition, the influence of different austenitizing temperatures and holding times on the metastable microstructural states after heat treatment/hardening is investigated. The experimental implementation of the heat treatment is used in a quenching dilatometer, and a microstructural simulation model is built using these results. As validation of the model, on the one hand, the martensite start temperature (Ms) is used, measured experimentally by dilatometry. Additionally, the carbide content and distribution, as determined by quantitative image analysis, are compared with the simulated data and used as an indicator of the model accuracy. Through the developed simulation model, arbitrary heat treatment‐induced metastable microstructural states can be calculated. As a possible application of this model, the live‐adaption of the industrial heat treatment process in dependence on the batch chemical composition is discussed. [ABSTRACT FROM AUTHOR]

Background: Reaction networks (RNs) comprise a set X of species and a set R of reactions Y → Y ′ , each converting a multiset of educts Y ⊆ X into a multiset Y ′ ⊆ X of products. RNs are equivalent to directed hypergraphs. However, not all RNs necessarily admit a chemical interpretation. Instead, they might contradict fundamental principles of physics such as the conservation of energy and mass or the reversibility of chemical reactions. The consequences of these necessary conditions for the stoichiometric matrix S ∈ R X × R have been discussed extensively in the chemical literature. Here, we provide sufficient conditions for S that guarantee the interpretation of RNs in terms of balanced sum formulas and structural formulas, respectively. Results: Chemically plausible RNs allow neither a perpetuum mobile, i.e., a "futile cycle" of reactions with non-vanishing energy production, nor the creation or annihilation of mass. Such RNs are said to be thermodynamically sound and conservative. For finite RNs, both conditions can be expressed equivalently as properties of the stoichiometric matrix S . The first condition is vacuous for reversible networks, but it excludes irreversible futile cycles and—in a stricter sense—futile cycles that even contain an irreversible reaction. The second condition is equivalent to the existence of a strictly positive reaction invariant. It is also sufficient for the existence of a realization in terms of sum formulas, obeying conservation of "atoms". In particular, these realizations can be chosen such that any two species have distinct sum formulas, unless S implies that they are "obligatory isomers". In terms of structural formulas, every compound is a labeled multigraph, in essence a Lewis formula, and reactions comprise only a rearrangement of bonds such that the total bond order is preserved. In particular, for every conservative RN, there exists a Lewis realization, in which any two compounds are realized by pairwisely distinct multigraphs. Finally, we show that, in general, there are infinitely many realizations for a given conservative RN. Conclusions: "Chemical" RNs are directed hypergraphs with a stoichiometric matrix S whose left kernel contains a strictly positive vector and whose right kernel does not contain a futile cycle involving an irreversible reaction. This simple characterization also provides a concise specification of random models for chemical RNs that additionally constrain S by rank, sparsity, or distribution of the non-zero entries. Furthermore, it suggests several interesting avenues for future research, in particular, concerning alternative representations of reaction networks and infinite chemical universes. [ABSTRACT FROM AUTHOR]

The special electronic structure of gold gives rise to many interesting phenomena, such as its color. The surface segregation of the silver-gold system has been the subject of numerous experimental and theoretical studies, yielding conflicting results ranging from strong Ag surface enrichment to Au surface segregation. Via a combined approach of density functional theory (DFT) and statistical physics, we have analyzed the segregation at the Ag-Au (111) surface with different Ag bulk concentrations. Interestingly, we observe a moderate Au surface segregation, which is due to a charge transfer from the less electronegative Ag to Au. Canonical Monte Carlo simulations suggest that the calculated concentration profile with a Au-enriched surface layer remains stable up to higher temperatures. However, the presence of adsorbed oxygen reverses the segregation behavior and leads to strong Ag enrichment of the surface layer. [ABSTRACT FROM AUTHOR]

Traditional (genome-scale) metabolic models of cellular growth involve an approximate biomass "reaction", which specifies biomass composition in terms of precursor metabolites (such as amino acids and nucleotides). On the one hand, biomass composition is often not known exactly and may vary drastically between conditions and strains. On the other hand, the predictions of computational models crucially depend on biomass. Also elementary flux modes (EFMs), which generate the flux cone, depend on the biomass reaction. To better understand cellular phenotypes across growth conditions, we introduce and analyze new classes of elementary vectors for comprehensive (next-generation) metabolic models, involving explicit synthesis reactions for all macromolecules. Elementary growth modes (EGMs) are given by stoichiometry and generate the growth cone. Unlike EFMs, they are not support-minimal, in general, but cannot be decomposed "without cancellations". In models with additional (capacity) constraints, elementary growth vectors (EGVs) generate a growth polyhedron and depend also on growth rate. However, EGMs/EGVs do not depend on the biomass composition. In fact, they cover all possible biomass compositions and can be seen as unbiased versions of elementary flux modes/vectors (EFMs/EFVs) used in traditional models. To relate the new concepts to other branches of theory, we consider autocatalytic sets of reactions. Further, we illustrate our results in a small model of a self-fabricating cell, involving glucose and ammonium uptake, amino acid and lipid synthesis, and the expression of all enzymes and the ribosome itself. In particular, we study the variation of biomass composition as a function of growth rate. In agreement with experimental data, low nitrogen uptake correlates with high carbon (lipid) storage. Author summary: Next-generation, genome-scale metabolic models allow to study the reallocation of cellular resources upon changing environmental conditions, by not only modeling flux distributions, but also expression profiles of the catalyzing proteome. In particular, they do no longer assume a fixed biomass composition. Methods to identify optimal solutions in such comprehensive models exist, however, an unbiased understanding of all feasible allocations is missing so far. Here we develop new concepts, called elementary growth modes and vectors, that provide a generalized definition of minimal pathways, thereby extending classical elementary flux modes (used in traditional models with a fixed biomass composition). The new concepts provide an understanding of all possible flux distributions and of all possible biomass compositions. In other words, elementary growth modes and vectors are the unique functional units in any comprehensive model of cellular growth. As an example, we show that lipid accumulation upon nitrogen starvation is a consequence of resource allocation and does not require active regulation. Our work puts current approaches on a theoretical basis and allows to seamlessly transfer existing workflows (e.g. for the design of cell factories) to next-generation metabolic models. [ABSTRACT FROM AUTHOR]

Ribosomes are key to cellular self-fabrication and limit growth rate. While most enzymes are proteins, ribosomes consist of 1/3 protein and 2/3 ribonucleic acid (RNA) (in E. coli). Here, we develop a mechanistic model of a self-fabricating cell, validated across diverse growth conditions. Through resource balance analysis (RBA), we explore the variation in maximum growth rate with ribosome composition, assuming constant kinetic parameters. Our model highlights the importance of RNA instability. If we neglect it, RNA synthesis is always cheaper than protein synthesis, leading to an RNA-only ribosome at maximum growth rate. Upon accounting for RNA turnover, we find that a mixed ribosome composed of RNA and proteins maximizes growth rate. To account for RNA turnover, we explore two scenarios regarding the activity of RNases. In (a) degradation is proportional to RNA content. In (b) ribosomal proteins cooperatively mitigate RNA instability by protecting it from misfolding and subsequent degradation. In both cases, higher protein content elevates protein synthesis costs and simultaneously lowers RNA turnover expenses, resulting in mixed RNA-protein ribosomes. Only scenario (b) aligns qualitatively with experimental data across varied growth conditions. Our research provides fresh insights into ribosome biogenesis and evolution, paving the way for understanding protein-rich ribosomes in archaea and mitochondria. Mechanistic modeling (resource balance analysis) links ribosome composition to growth rate. Only if the costs of ribosomal RNA stabilization are taken into account, maximum growth occurs for a mixed (RNA+protein) ribosome, as observed experimentally. [ABSTRACT FROM AUTHOR]

Experiences from the past and present influence decision-making. Voting behavior at elections also involves retrospective and prospective considerations. Yet, we do not know the degree to which parties react to these considerations by emphasizing the past, present, and future. I posit that parties do not only make promises but face incentives to discuss the past and present. I also expect that incumbency status conditions emotive rhetoric across these temporal dimensions. Using supervised machine learning, I uncover the temporal rhetorical focus in 621 party manifestos published in nine countries between 1949 and 2017. Parties devote, on average, half of a manifesto to future promises, while the other half describes the past and present. I also show that statements on the past and present drive previously observed differences in sentiment between incumbents and opposition parties. The findings underscore how the temporal dimension of campaign communication enhances our understanding of party competition. [ABSTRACT FROM AUTHOR]

The Irish party system has been an outlier in comparative politics. Ireland never had a left-right divide in parliament, and for decades, the dominant centrist political parties competed around a centre-right policy agenda. The absence of an explicit left-right divide in party competition suggested that Irish voters, on average, occupy centre-right policy preferences. Combining survey data since 1973 and all Irish election studies between 2002 and 2020, we show that the average Irish voter now leans to the centre-left. We also show that income has recently emerged as a predictor of left-right self-placement, and that left-right positions increasingly structure vote choice. These patterns hold when using policy preferences on taxes, spending, and government interventions to reduce inequality as alternative indicators. We outline potential explanations for this leftward shift, and conclude that these developments might be anchored in economic inequalities and the left populist strategies of Sinn Féin. [ABSTRACT FROM AUTHOR]

Let Ω ⊂ R 3 be an open and bounded set with Lipschitz boundary and outward unit normal ν . For 1 < p < ∞ we establish an improved version of the generalized L p -Korn inequality for incompatible tensor fields P in the new Banach space W 0 1 , p , r (dev sym Curl ; Ω , R 3 × 3) = { P ∈ L p (Ω ; R 3 × 3) ∣ dev sym Curl P ∈ L r (Ω ; R 3 × 3) , dev sym (P × ν) = 0 on ∂ Ω } where r ∈ [ 1 , ∞) , 1 r ≤ 1 p + 1 3 , r > 1 if p = 3 2. Specifically, there exists a constant c = c (p , Ω , r) > 0 such that the inequality ‖ P ‖ L p (Ω , R 3 × 3) ≤ c ‖ sym P ‖ L p (Ω , R 3 × 3) + ‖ dev sym Curl P ‖ L r (Ω , R 3 × 3) holds for all tensor fields P ∈ W 0 1 , p , r (dev sym Curl ; Ω , R 3 × 3) . Here, dev X : = X - 1 3 tr (X) 1 denotes the deviatoric (trace-free) part of a 3 × 3 matrix X and the boundary condition is understood in a suitable weak sense. This estimate also holds true if the boundary condition is only satisfied on a relatively open, non-empty subset Γ ⊂ ∂ Ω . If no boundary conditions are imposed then the estimate holds after taking the quotient with the finite-dimensional space K S , d S C which is determined by the conditions sym P = 0 and dev sym Curl P = 0 . In that case one can replace ‖ dev sym Curl P ‖ L r (Ω , R 3 × 3) by ‖ dev sym Curl P ‖ W - 1 , p (Ω , R 3 × 3) . The new L p -estimate implies a classical Korn's inequality with weak boundary conditions by choosing P = D u and a deviatoric-symmetric generalization of Poincaré's inequality by choosing P = A ∈ so (3) . The proof relies on a representation of the third derivatives D 3 P in terms of D 2 dev sym Curl P combined with the Lions lemma and the Nečas estimate. We also discuss applications of the new inequality to the relaxed micromorphic model, to Cosserat models with the weakest form of the curvature energy, to gradient plasticity with plastic spin and to incompatible linear elasticity. [ABSTRACT FROM AUTHOR]

From an epistemological point of view, tentativeness is an important feature of scientific knowledge. With regard to current debates on "fake science", it becomes also significant within science education. The article provides a proposal for clarifying the term. In addition, results of two qualitative studies are presented. They reveal that most preservice chemistry teachers held inconsistent views on tentativeness, which are furthermore resistant to change. In order to promote a more adequate understanding, it is necessary to deal intensively with the tentative nature of science as well as to address the durability and reliability of well‐supported scientific knowledge. Further approaches to promote an adequate and functional understanding are presented and discussed. [ABSTRACT FROM AUTHOR]

Herein, a comprehensive model is presented for the calculation of entire current-voltage (IV) characteristics of Schottky contacts (SCs). This treatment allows to analyze in detail the physical and technological origins of empirical fit parameters like the ideality factor. This model considers variations of the semiconductor net doping density in growth direction and barrier height inhomogeneities. The only input parameters required are the doping profile, the mean value, and the standard deviation of the barrier height distribution as well as material parameters. As measuring conditions like the integration time impact measured IV characteristics, similar sweep parameters as applied during a measurement are included in the model and proven to be necessary for the understanding of charging currents and the shift of the voltage for zero current. Using this model, various nonidealities reported in literature are explained. Further, the influence of differently doped interfacial layers on the characteristics is studied. Finally, the model is applied to multiple datasets of IV characteristics of SCs on different materials published in literature and from this laboratory, enabling a fundamental understanding of the origins of the nonidealities observed as well as the distinction between the contributions of different transport mechanisms to the total current. [ABSTRACT FROM AUTHOR]

• Emerging connection between the nucleolar stress response and autophagy. • Involvement of the ubiquitin-proteasome system (UPS) and autophagy in ribosome biogenesis and protein homeostasis. • Impaired ribosome biogenesis induces nucleolar stress and p53 activation. • Autophagy activation in response to nucleolar stress as a cytoprotective mechanism. The nucleolus functions as the cellular hub for the initiation and early steps of ribosome biogenesis. Ribosomes are key components of the translation machinery and, accordingly, their abundance needs to be adjusted to the cellular energy status. Further, to ensure translational fidelity, the integrity and quality of ribosomes needs to be monitored under conditions of cellular stress. Stressful insults, such as nutrient, genotoxic or proteotoxic stress, interfere with ribosome biogenesis and activate a cellular response referred to as nucleolar stress. This nucleolar stress response typically affects nucleolar integrity and is intricately linked to the activation of protein quality control pathways, including (i) the ubiquitin proteasome system (UPS) and (ii) the autophagy machinery, to restore cellular proteostasis. Here we will review some key features of the nucleolar stress response with a particular focus on the role of the UPS and autophagy in this process. [ABSTRACT FROM AUTHOR]

We present a comprehensive comparison of electrical properties of differently fabricated high quality Schottky contacts on ZnO thin films grown by pulsed laser deposition. Thermally evaporated Pd/ZnO Schottky contacts exhibit ideality factors as low as 1.06 due to their high lateral homogeneity. The effective Richardson constant determined using these homogeneous contacts is (7.7±4.8)Acm-2 K-2 close to the theoretical value of 32Acm-2 K-2. However, their rectification ratio is at most five orders of magnitude due to their comparably small barrier height (≈0:7eV). The largest effective barrier height (1:11 eV) and rectification ratio (7 × 1010) was obtained for reactively sputtered PdOx/ZnO Schottky contacts. Eclipse pulsed laser deposited IrOx/ZnO Schottky contacts were found to combine very good lateral homogeneity (n ≈ 1:1), with a reasonably large barrier height (0:96 eV) and large rectification ratio (≈9 orders of magnitude). Our results for differently fabricated Schottky contacts suggest that the barrier formation is highly dependent on the presence of oxygen vacancies close to the interface and the different compensation mechanisms involved. [ABSTRACT FROM AUTHOR]

We have investigated the impact of strain on the incorporation and the properties of extended and point defects in (Mg,Zn)O thin films by means of photoluminescence, X-ray diffraction, deep-level transient spectroscopy (DLTS), and deep-level optical spectroscopy. The recombination line Y2, previously detected in ZnO thin films grown on an Al-doped ZnO buffer layer and attributed to tensile strain, was exclusively found in (Mg,Zn)O samples being under tensile strain and is absent in relaxed or compressively strained thin films. Furthermore a structural defect E3' can be detected via DLTS measurements and is only incorporated in tensile strained samples. Finally it is shown that the omnipresent deep-level E3 in ZnO can only be optically recharged in relaxed ZnO samples. [ABSTRACT FROM AUTHOR]

A high‐voltage AlN/GaN superlattice (SL) buffer for monolithic AlGaN/GaN power circuits is experimentally compared with a step‐graded AlGaN/GaN buffer. The SL as part of a 5.1 μm epitaxial stack withstands over 1.3 kV. Although the step‐graded buffer is sufficient for low‐side circuits, the operation voltage of monolithic topologies such as a half‐bridge is limited: static negative back gating at −200 V depletes the lateral channel completely. Asymmetrical buffer leakage at a positive substrate voltage of +250 V limits the operation voltage further. The SL buffer mitigates both effects: a negative substrate voltage of −200 V reduced the lateral channel current only by 25%. However, this condition is not required for half‐bridge operation on the SL, because low symmetrical vertical buffer leakage at substrate voltages of ±500 V allows operation of power topologies with positive substrate bias. High‐electron‐mobility transistors (HEMTs) on the graded buffer show excessive threshold voltage shift at negative substrate bias. On the SL buffer, the threshold voltage is shifted only +1 V from negative substrate biases, which allows monolithic high‐voltage power topology operation. 98.8% efficient operation of a 6 × 4 mm2 GaN‐on‐Si power integrated circuit with a monolithic half bridge, freewheeling diodes, and drivers is demonstrated on the SL. [ABSTRACT FROM AUTHOR]

Previous studies conclude that governments fulfill a large share of their campaign pledges. However, only a minority of voters believe that politicians try to keep their promises, and many voters struggle to recall the fulfillment or breaking of salient campaign pledges accurately. I argue that this disparity between the public perception and empirical evidence is influenced by the information voters receive throughout the electoral cycle. I expect that the media extensively inform readers about political promises. In addition, I posit that news outlets focus more on broken than on fulfilled promises and that the focus on broken promises has increased over time. I find strong support for these expectations based on a new text corpus of over 430,000 statements on political commitments published between 1979 and 2017 in 22 newspapers during 33 electoral cycles in Australia, Canada, Ireland, and the United Kingdom. Newspapers inform voters regularly about announced, broken, and fulfilled promises. Yet, across the four countries, newspapers report at least twice as much on broken than on fulfilled promises. Moreover, this negativity bias in reports on political promises has increased substantively. The results have implications for studying campaign promises, negative information in mass media, and the linkages between voters and parties. [ABSTRACT FROM AUTHOR]

We further clarify the relation between detailed-balanced and complex-balanced equilibria of reversible chemical reaction networks. Our results hold for arbitrary kinetics and also for boundary equilibria. Detailed balance, complex balance, “formal balance,” and the new notion of “cycle balance” are all defined in terms of the underlying graph. This fact allows elementary graph-theoretic (non-algebraic) proofs of a previous result (detailed balance = complex balance + formal balance), our main result (detailed balance = complex balance + cycle balance), and a corresponding result in the setting of continuous-time Markov chains. [ABSTRACT FROM AUTHOR]

In times of distance learning, many chemistry teachers wish they had more possibilities to provide learners with chemical content knowledge digitally and in a differentiated way. This publication presents possibilities for developing and testing digital learning environments for chemical content using simple functions. With just a few clicks, PowerPoint presentations can be transformed into "point‐and‐click" learning environments. In the project "e‐lement", student teachers from the University of Cologne tested and evaluated these functions in a school context with learners. [ABSTRACT FROM AUTHOR]

We prove an optimal-order error bound in the discrete H2() norm for finite difference approximations of the first boundary-value problem for the biharmonic equation in n space dimensions, with n 2 f2; : : : ; 7g, whose generalized solution belongs to the Sobolev space Hs()\H2 0 () for 1 2 max(5; n) < s 4, where = (0; 1)n. The result extends the range of the Sobolev index s in the best convergence results currently available in the literature to the maximal range admitted by the Sobolev embedding of Hs() into C() in n space dimensions. [ABSTRACT FROM AUTHOR]

Photosynthetic organisms developed various strategies to mitigate high light stress. For instance, aquatic organisms are able to spend excessive energy by exchanging dissolved CO2 (dCO2) and bicarbonate (HCO3−) with the environment. Simultaneous uptake and excretion of the two carbon species is referred to as inorganic carbon cycling. Often, inorganic carbon cycling is indicated by displacements of the extracellular dCO2 signal from the equilibrium value after changing the light conditions. In this work, we additionally use (i) the extracellular pH signal, which requires non‐ or weakly‐buffered medium, and (ii) a dynamic model of carbonate chemistry in the aquatic environment to detect and quantitatively describe inorganic carbon cycling. Based on simulations and experiments in precisely controlled photobioreactors, we show that the magnitude of the observed dCO2 displacement crucially depends on extracellular pH level and buffer concentration. Moreover, we find that the dCO2 displacement can also be caused by simultaneous uptake of both dCO2 and HCO3− (no inorganic carbon cycling). In a next step, the dynamic model of carbonate chemistry allows for a quantitative assessment of cellular dCO2, HCO3−, and H+ exchange rates from the measured dCO2 and pH signals. Limitations of the method are discussed. [ABSTRACT FROM AUTHOR]

We present a novel C 0 -characterization of symplectic embeddings and diffeomorphisms in terms of Lagrangian embeddings. Our approach is based on the shape invariant, which was discovered by Sikorav and Eliashberg, intersection theory and the displacement energy of Lagrangian submanifolds, and the fact that non-Lagrangian submanifolds can be displaced immediately. This characterization gives rise to a new proof of C 0 -rigidity of symplectic embeddings and diffeomorphisms. The various manifestations of Lagrangian rigidity that are used in our arguments come from J -holomorphic curve methods. An advantage of our techniques is that they can be adapted to a C 0 -characterization of contact embeddings and diffeomorphisms in terms of coisotropic (or pre-Lagrangian) embeddings, which in turn leads to a proof of C 0 -rigidity of contact embeddings and diffeomorphisms. We give a detailed treatment of the shape invariants of symplectic and contact manifolds, and demonstrate that shape is often a natural language in symplectic and contact topology. We consider homeomorphisms that preserve shape, and propose a hierarchy of notions of Lagrangian topological submanifold. Moreover, we discuss shape-related necessary and sufficient conditions for symplectic and contact embeddings, and define a symplectic capacity from the shape. [ABSTRACT FROM AUTHOR]

Signed distance fields represent objects as distances to the closest surface points with a sign differentiating inside and outside. We present an algorithm to compute a signed distance field from triangle meshes. All data are kept on the GPU, making it ideal for any pure graphics-based context. We split the algorithm into a fast parallel distance transform and a new method of computing the sign. To determine the sign, we compute the winding number for any point using a ray map, a ray-based data structure that preserves geometric meaning while reducing the amount of work to be done for ray tests. Based on that structure, we devise a simple parallel algorithm to sample an exponentially growing number of rays to cope with meshes having deficiencies such as holes or self-intersections. We demonstrate how our method is both fast and able to handle imperfect meshes. [ABSTRACT FROM AUTHOR]

Which voters prefer having more choice between parties and candidates in an election? To provide an answer to this question, we analyse the case of a radical change from a closed-list PR system to a highly complex open-list PR system with cumulative voting in the German states of Bremen and Hamburg. We argue that the approval of a personalised electoral system is structured in similar ways as support for direct democracy. Using representative surveys conducted prior to all four state elections under cumulative voting in 2011 and 2015, we analyse which individual factors determine the approval, disapproval, or indifference towards the new electoral law. The results indicate that younger voters as well as supporters of left parties are much more likely to support a personalised electoral system. In contrast to previous studies, political interest only has an impact on the indifference towards the electoral system. More generally, our results show that a large proportion of voters does not appreciate personalised preferential electoral systems which seems to be a result of the complexity and magnitude of choice between parties and candidates. [ABSTRACT FROM AUTHOR]

We present conditions which guarantee a parametrization of the set of positive equilibria of a generalized mass-action system. Our main results state that (1) if the underlying generalized chemical reaction network has an effective deficiency of zero, then the set of positive equilibria coincides with the parametrized set of complex-balanced equilibria and (2) if the network is weakly reversible and has a kinetic deficiency of zero, then the equilibrium set is nonempty and has a positive, typically rational, parametrization. Via the method of network translation, we apply our results to classical mass-action systems studied in the biochemical literature, including the EnvZ-OmpR and shuttled WNT signaling pathways. A parametrization of the set of positive equilibria of a (generalized) mass-action system is often a prerequisite for the study of multistationarity and allows an easy check for the occurrence of absolute concentration robustness, as we demonstrate for the EnvZ-OmpR pathway. [ABSTRACT FROM AUTHOR]

Motivation Elementary flux mode (EFM) analysis allows an unbiased description of metabolic networks in terms of minimal pathways (involving a minimal set of reactions). To date, the enumeration of EFMs is impracticable in genome-scale metabolic models. In a complementary approach, we introduce the concept of a flux tope (FT), involving a maximal set of reactions (with fixed directions), which allows one to study the coordination of reaction directions in metabolic networks and opens a new way for EFM enumeration. Results A FT is a (nontrivial) subset of the flux cone specified by fixing the directions of all reversible reactions. In a consistent metabolic network (without unused reactions), every FT contains a 'maximal pathway', carrying flux in all reactions. This decomposition of the flux cone into FTs allows the enumeration of EFMs (of individual FTs) without increasing the problem dimension by reaction splitting. To develop a mathematical framework for FT analysis, we build on the concepts of sign vectors and hyperplane arrangements. Thereby, we observe that FT analysis can be applied also to flux optimization problems involving additional (inhomogeneous) linear constraints. For the enumeration of FTs, we adapt the reverse search algorithm and provide an efficient implementation. We demonstrate that (biomass-optimal) FTs can be enumerated in genome-scale metabolic models of B.cuenoti and E.coli, and we use FTs to enumerate EFMs in models of M.genitalium and B.cuenoti. Availability and implementation The source code is freely available at https://github.com/mpgerstl/FTA. Supplementary information Supplementary data are available at Bioinformatics online. [ABSTRACT FROM AUTHOR]

The propagation of reaction-diffusion fronts in an open liquid solution layer is critically affected by mass transfer between the liquid solution and the adjacent gas phase. This is the case in the iodate-arsenous acid (IAA) reaction when run under stoichiometric excess of iodate. Here, iodine is the reaction product, which has a low solubility in the liquid phase, hence, excess iodine rapidly evaporates. In the gas phase, it diffuses and overtakes the reaction front propagating in the liquid medium because its diffusion coefficient in the gas phase is considerably larger than that in aqueous solution. Evaporated iodine is re-dissolved into the reaction medium ahead of the reaction front. Since iodine is the autocatalytic species of the IAA reaction, this additional gas-phase transport may lead to an acceleration of the propagating reaction front. [ABSTRACT FROM AUTHOR]

Chemical fronts and waves travelling in reaction-diffusion systems frequently induce hydrodynamic flow. This adds an additional transport process to the mechanism of spatio-temporal structure formation and can lead to an acceleration of the chemical (reaction) front. We report on the acceleration of travelling chemical fronts elicited by convection, as caused by the Marangoni effect in the monostable iodate-arsenous acid reaction in a thin liquid film. At a stoichiometric excess of iodate over arsenous acid, the reaction produces a large amount of iodine, which is surface-active. At the reaction front, iodine is transferred from the bulk to the surface inducing spatio-temporal gradients of surface tension that lead to capillary flows. These flows, in turn, promote further iodine adsorption at the surface through hydrodynamic mixing effects. As a consequence, an acceleration of the chemical fronts is observed, even if the concentration difference across the front is constant. After the transient acceleration of the reaction front, it settles at a constant propagation velocity, which is assumed to be regulated by a balance in the mass transfer between the bulk and the surface. [ABSTRACT FROM AUTHOR]

Objective: The objective structured clinical examination (OSCE) has become widely accepted as a form of assessment in medical education. At the same time, the more traditional multiple choice question (MCQ) examinations remain a central modality of student assessment. This pilot survey aimed to investigate students' perceptions about the bene- fits of the OSCE and MCQs to yield data supporting the implementation of this assessment strategy into the national medical licensing examination in Germany. Methods: A questionnaire was delivered electronically to 34 German medical schools. Students in years 3-6 were invited to rate 11 items about objectives of good medical assessment. All items were presented for both the OSCE and MCQs using a 5-point Likert Scale (1=strongly disagree to 5=strongly agree). Factor analysis was used to identify un- derlying components in the ratings. Average scores of items that be- longed to a component were computed. Results: Data analysis included 1,082 students from 32 medical schools. For the OSCE, factor analysis revealed two components, which were labelled "educational impact" and "development of clinical com- petence". The average scores of items were 3.37 and 3.55, respectively. For the MCQ modality, also two components emerged. These were la- belled "perceived weaknesses of MCQs" and "perceived strengths of MCQs" (consisting of items such as "promotes my theoretical knowledge"). The average scores for these components were 1.85 and 3.62. Conclusion: The results of this pilot survey indicate that students consider both OSCE and MCQs as useful assessments for the purposes for which they were designed. The assessment strategy thus appears appropriate and it should be used in the national licensing examination. [ABSTRACT FROM AUTHOR]

Background: The optimization of metabolic rates (as linear objective functions) represents the methodical core of flux-balance analysis techniques which have become a standard tool for the study of genome-scale metabolic models. Besides (growth and synthesis) rates, metabolic yields are key parameters for the characterization of biochemical transformation processes, especially in the context of biotechnological applications. However, yields are ratios of rates, and hence the optimization of yields (as nonlinear objective functions) under arbitrary linear constraints is not possible with current flux-balance analysis techniques. Despite the fundamental importance of yields in constraint-based modeling, a comprehensive mathematical framework for yield optimization is still missing. Results: We present a mathematical theory that allows one to systematically compute and analyze yield-optimal solutions of metabolic models under arbitrary linear constraints . In particular, we formulate yield optimization as a linear-fractional program. For practical computations, we transform the linear-fractional yield optimization problem to a (higher-dimensional) linear problem. Its solutions determine the solutions of the original problem and can be used to predict yield-optimal flux distributions in genome-scale metabolic models. For the theoretical analysis, we consider the linear-fractional problem directly. Most importantly, we show that the yield-optimal solution set (like the rate-optimal solution set) is determined by (yield-optimal) elementary flux vectors of the underlying metabolic model. However, yield- and rate-optimal solutions may differ from each other, and hence optimal (biomass or product) yields are not necessarily obtained at solutions with optimal (growth or synthesis) rates. Moreover, we discuss phase planes/production envelopes and yield spaces, in particular, we prove that yield spaces are convex and provide algorithms for their computation. We illustrate our findings by a small example and demonstrate their relevance for metabolic engineering with realistic models of E. coli . Conclusions: We develop a comprehensive mathematical framework for yield optimization in metabolic models. Our theory is particularly useful for the study and rational modification of cell factories designed under given yield and/or rate requirements. [ABSTRACT FROM AUTHOR]

This paper is a reply to Benjamin Bruening's article 'The lexicalist hypothesis: Both wrong and superfluous', which appears in this volume of Language. Bruening claims that all phenomena that have been explained with reference to the notion word should be explained with reference to the X0/XP distinction. He claims that only phrases can be extracted, which would explain the island status of words (his X0). He also claims that coordination always affects full XPs, countering an earlier argument by Steve Wechsler and me. He argues for a phrasal analysis of resultative constructions and tries to support it by the claim that all arguments of nouns are optional, and hence a lexical analysis of resultative constructions that assumes that the result predicate is selected by the verb would make wrong claims when it comes to nominalizations, since one would expect that the result predicate can be omitted like other arguments in nominalizations can be. I argue that Bruening's X0/XP distinction cannot explain extraction differences since X0 can be extracted, that some arguments are indeed not optional in nominalizations, and that coordination may affect lexical items. I furthermore point out that morphological phenomena in languages other than English may need more machinery and different tools and that in the end it may be reasonable to assume that there is a morphology that is indeed different from syntax. [ABSTRACT FROM AUTHOR]

Although carbonyl iron powder (CIP) is an old material for magnetic applications (e.g. inductor cores), the structure of this material is still described controversially in literature. On the first glance a greyish powder exhibiting a spherical structure, CIP reveals on the second glance a nanoscopic crystalline sub-structure. The material itself contains carbon and nitrogen and its structure is described as an onion-type structure. However, the nature of the different shells and clarity on the nature of the involved carbidic and/or nitridic phases, be they crystalline, amorphous or solid solutions has not yet been achieved. In addition, it is known, that CIP transforms in H2-atmosphere to a "soft" grade, consisting of pure Fe. Again, chemical and microstructural knowledge on the transition from the "hard" to the "soft" CIP is lacking. This leads to the motivation of this study: 1. Unambiguously identify the nature and existence of the involved phases in the unreduced and hard carbonyl iron powder and in the reduced and soft iron powder particles 2. Characterize the phase transformations and microstructural changes of CIP during the thermic treatment in a hydrogen atmosphere. Different techniques were used to clarify the above mentioned points like in-situ synchrotron XRPD accompanied by electron microscopy techniques. [ABSTRACT FROM AUTHOR]

Herein, the electrical and thermal performance of lateral AlGaN/GaN high electron mobility transistors (HEMTs) and metal‐insulator‐semiconductor field effect transistors (MISFETs) fabricated with 11 μm thick GaN buffer layers on 200 mm diameter Qromis Substrate Technology (QST) substrates are investigated. The QST substrate has a polycrystalline core engineered to be coefficient of thermal expansion (CTE)‐matched to GaN to minimize wafer bow and residual stress in the GaN film as a result of epitaxial growth. Raman spectroscopy is used to determine the biaxial residual stress in the GaN buffer of the as‐fabricated devices. Electrical characterization is demonstrated on the HEMTs including DC and pulsed output characteristics, DC transfer characteristics, Hall mobility, carrier concentration, sheet resistance, median transition frequency, and maximum stable gain. Finally, the thermal performance of the AlGaN/GaN MISFET is assessed via thermoreflectance thermal imaging at DC power densities up to 19 W mm−1. The thermal resistance of the MISFET, calculated using the peak temperature rises on the gate electrode for DC power densities <10 W mm−1, is measured to be 15.4 mm K W−1, which is comparable with state‐of‐the‐art GaN‐on‐Si lateral transistors. [ABSTRACT FROM AUTHOR]

Background: Changes in glucose and energy metabolism contribute to the altered phenotype of cancer cells and are the basis for positron emission tomography with 18F-fluoro-2-deoxy-D-glucose (FDG) to visualize tumors in vivo. The molecular background of the enhanced glucose uptake and its regulation in lymphoma cells is not fully clarified and may provide new possibilities to reverse the altered metabolism. Thus in this study we investigated regulation of glucose uptake by different signaling pathways. Furthermore, the effect of the glucose analog 2-deoxy-D-glucose (2-DG) alone and in combination with other inhibitors on cell survival was studied.Methods: An FDG uptake assay was established and uptake of FDG by lymphoma cells was determined after incubation with inhibitors of the c-MYC and the PI3K signalling pathways that are known to be activated in lymphoma cells and able to regulate glucose metabolism. Inhibitors of MAPK signalling pathways whose role in altered metabolism is still unclear were also investigated. Expression of mRNAs of the glucose transporter 1 (GLUT1), hexokinase 2 (HK2), glucose-6-phosphatase (G6Pase) and lactate dehydrogenase A (LDHA) and of the glucose metabolism-regulating micro RNAs (miRNA) miR21, -23a, -133a, -133b, -138-1 and -143 was determined by RT-PCR. Cell viability was analysed by MTT assay.Results: Treatment with the c-MYC inhibitor 10058-F4 and inhibitors of the PI3K/mTOR pathway diminished uptake of FDG in all three cell lines, while inhibition of MAPK pathways had no effect on glucose uptake. Expression of glycolysis-related genes and miRNAs were diminished, although to a variable degree in the three cell lines. The c-MYC inhibitor, the PI3K inhibitor LY294002, the mTOR inhibitor Rapamycin and 2-DG all diminished the number of viable cells. Interestingly, in combination with 2-DG, the c-MYC inhibitor, LY294002 and the p38 MAPK inhibitor SB203580 had synergistic effects on cell viability in all three cell lines.Conclusions: c-MYC- and PI3K/mTOR-inhibitors decreased viability of the lymphoma cells and led to decreased glucose uptake, expression of glycolysis-associated genes, and glucose metabolism-regulating miRNAs. Inhibition of HK by 2-DG reduced cell numbers as a single agent and synergistically with inhibitors of other intracellular pathways. Thus, targeted inhibition of the pathways investigated here could be a strategy to suppress the glycolytic phenotype of lymphoma cells and reduce proliferation. [ABSTRACT FROM AUTHOR]

The 2445–2010 Ma tectonic evolution of the southwestern Pilbara Craton is recorded by two depositional basins, but considering the time span involved it is pertinent to question whether only two are preserved and others have vanished. The first, the Turee Creek Basin, developed conformably on an ∼2450 Ma back-arc volcanic province, and was closed long before ∼2208 Ma. It was a retroarc basin sited in front of a magmatic fold-thrust belt on the southwestern margin of the craton. Its folded strata were intruded by ∼2208 Ma dolerite sills that are the preserved rock record of a large igneous province. The basin and dolerites were deformed by the N-verging ∼2195–2145 Ma Ophthalmia Fold-Thrust Belt. The second, the Horseshoe Basin, formed at ≤2050 Ma, unconformably truncating folded strata of the Turee Creek Basin and the ∼2208 Ma dolerites, and was closed prior to intrusion of ∼2008 Ma dolerite dykes. It was an intracontinental rift basin sited on the inverted fold-thrust belt. Detrital zircon age-spectra for the basins have poor fit to the zircon age-spectrum of the Pilbara, and differ significantly in their youngest modes. The youngest mode for the Turee Creek Basin is ∼2442 Ma, whereas the youngest mode for the Horseshoe Basin decreases upwards from ∼2276 Ma to ∼2206 Ma. Although differing in youngest detrital zircon age-modes, zircon age-spectra of the basins are otherwise similar, and broadly match the Glenburgh Terrane on the southwestern margin of the craton. While Turee Creek sediments were derived from the southwest, Horseshoe sediments were derived from the north and northeast. This conundrum is resolved by the Ophthalmia Fold-Thrust Belt, which tectonically loaded the craton to the north and northeast to form a now-vanished Ophthalmia foreland basin that derived sediment from the south and southwest, thereby emplacing zircon with an exotic age-spectrum on the North Pilbara. Inversion of tectonic elements occurred during formation of the Horseshoe Basin, with the fold-thrust belt subsiding beneath the rift while the foreland basin was uplifted. Recycling of the foreland basin inverted its detrital zircon age-spectrum, explaining why the youngest detrital zircon age-mode of the Horseshoe Basin decreases in age upwards. [ABSTRACT FROM AUTHOR]

Purpose: Therapy with the alpha-emitter radium-223 chloride (Ra) is an innovative therapeutic option in patients with metastasized, castration-resistant prostate cancer. However, radiotherapy can lead to hematopoietic toxicity. The aim of this study was to determine if Ra therapy induces an impairment of cellular antimicrobial immune responses. Methods: In 11 patients receiving Ra treatment, lymphocyte proliferation and the production of pro- and anti-inflammatory cytokines (interferon-γ and interleukin-10) were determined, using lymphocyte transformation testing and ELISpot, respectively. Lymphocyte function after stimulation with mitogens and microbial antigens was assessed prior to therapy and at day 1, 7 and 28 after therapy. Results: Lymphocyte proliferation and the production of interferon-γ and interleukin-10 towards mitogens and antigens remained unchanged after therapy. Consistent with these in vitro data, we did not observe infectious complications after treatment. Conclusions: The results argue against an impairment of lymphocyte function after Ra therapy. Thus, immune responses against pathogens should remain unaffected. [ABSTRACT FROM AUTHOR]

Let Ω ⊂ ℝ n be bounded and open, let p ≧ n 2 /( n + 1) and let u : Ω → ℝ n be in the Sobolevspace W 1, n (Ω; ℝ n ). This paper discusses the singular part of the distributional determinant Det D u and shows the existence of functions u for which that singular part is supported in a set of prescribed Hausdorff-dimension α ∈ (0, n ). For n = 2 and simply connected Ω the problem is equivalent to analyzing div ( bv ) − b . D v where v ∈ W 1, p (Ω; ℝ 2 ) with div b = 0. [ABSTRACT FROM AUTHOR]