We present Step-Back Prompting, a simple prompting technique that enables LLMs to do abstractions to derive high-level concepts and first principles from instances containing specific details. Using the concepts and principles to guide the reasoning steps, LLMs significantly improve their abilities in following a correct reasoning path towards the solution. We conduct experiments of Step-Back Prompting with PaLM-2L models and observe substantial performance gains on a wide range of challenging reasoning-intensive tasks including STEM, Knowledge QA, and Multi-Hop Reasoning. For instance, Step-Back Prompting improves PaLM-2L performance on MMLU Physics and Chemistry by 7% and 11%, TimeQA by 27%, and MuSiQue by 7%.

This article reports a comparative study of bulk and surface properties in the transition metal dichalcogenide 1T−TaS2. When heating the sample, the surface displays an intermediate insulating phase that persists for ∼10 K on top of a metallic bulk. The weaker screening of Coulomb repulsion and a stiffer charge density wave (CDW) explain such resilience of a correlated insulator in the topmost layers. Both time-resolved angle-resolved photoelectron spectroscopy and transient reflectivity are employed to investigate the dynamics of electrons and CDW collective motion. It follows that the amplitude mode is always stiffer at the surface and displays variable coupling to the Mott-Peierls band, stronger in the low-temperature phase and weaker in the intermediate one.

We introduce two infinite sequences of entanglement monotones, which are constructed from expectation values of polynomials in the modular Hamiltonian. These monotones yield infinite sequences of inequalities that must be satisfied in majorizing state transitions. We demonstrate this for information erasure, deriving an infinite sequence of “Landauer inequalities” for the work cost, bounded by linear combinations of expectation values of powers of the modular Hamiltonian. These inequalities give improved lower bounds for the work cost in finite-dimensional systems, and depend on more details of the erased state than just on its entropy and variance of modular Hamiltonian. Similarly one can derive lower bounds for marginal entropy production for a system coupled to an environment. These infinite sequences of entanglement monotones also give rise to relative quantifiers that are monotonic in more general processes, namely those involving so-called σ majorization with respect to a fixed point full rank state σ; such quantifiers are called resource monotones. As an application to thermodynamics, one can use them to derive finite-dimension corrections to the Clausius inequality. Finally, in order to gain some intuition for what (if anything) plays the role of majorization in field theory, we compare pairs of states in discretized theories at criticality and study how majorization depends on the size of the bipartition with respect to the size of the entire chain.

We investigate how the breaking of charge conjugation symmetry C impacts on the dynamics of a half-filled fermionic lattice system after global quenches. We show that, when the initial state is insulating and the C symmetry is broken nonlocally by a constant magnetic flux, local observables, and correlations behave as if the symmetry were unbroken for a time interval proportional to the system size L. In particular, the local particle density of a quenched dimerized insulator remains pinned to 1/2 in each lattice site for an extensively long time, while it starts to significantly fluctuate only afterwards. Due to its qualitative resemblance to the sudden arrival of rapidly rising ocean waves, we dub this phenomenon the “tsunami effect.” Notably, it occurs even though the chiral symmetry is dynamically broken right after the quench. Furthermore, we identify a way to quantify the amount of symmetry breaking in the quantum state, showing that in insulators perturbed by a flux, it is exponentially suppressed as a function of the system size, while it is only algebraically suppressed in metals and in insulators with locally broken C symmetry. The robustness of the tsunami effect to weak disorder and interactions is demonstrated, and possible experimental realizations are proposed.

PrRhC2 belongs to the rare-earth carbides family, whose properties are of special interest among topological semimetals due to the simultaneous breaking of both inversion and time-reversal symmetry. The concomitant absence of both symmetries grants the possibility to tune the Weyl nodes chirality and to enhance topological effects such as the chiral anomaly. In this paper, we report on the synthesis and compare the magnetotransport measurements of polycrystalline PrRhC2 samples and a single-crystalline PrRhC2 sample. Using a remarkable and sophisticated technique, the PrRhC2 single crystal is prepared via focused-ion-beam cutting from the polycrystalline material. Our magnetometric and specific heat analyses reveal a noncollinear antiferromagnetic state below 20K, as well as short-range magnetic correlations and/or magnetic fluctuations well above the onset of the magnetic transition. The transport measurements on the PrRhC2 single crystal display an electrical resistivity peak at 3K and an anomalous Hall effect below 6K indicative of a net magnetization component in the ordered state. Furthermore, we study the angular variation of magnetoresistivities as a function of the angle between the in-plane magnetic field and the injected electrical current. We find that both the transverse and the longitudinal resistivities exhibit fourfold angular dependencies due to higher-order terms in the resistivity tensor, consistent with the orthorhombic crystal symmetry of PrRhC2. Our experimental results may be interpreted as features of topological Weyl semimetallic behavior in the magnetotransport properties.

Purpose This article presents a novel case study that analyzes the applicability of DoE in the curling sport in order to improve their own performance and the performance of its athletes. Specifically, this study analyzes the most important factors to increase accuracy and precision in the draw game with curlers' opinions. It was decided to use the “Last Stone Draw (LSD)’ as an appropriate play situation. Design/methodology/approach Specifically, this study analyzes most important factors to increase accuracy and precision in the draw game with curlers opinions from the German Curling association. Three research techniques were used in this study: case study, interviews and a well-designed experiment. The analysis through the use of DoE includes a measurement system analysis, an initial variance test between two players, a screening and a characterization experiment. Findings The results obtained from DoE suggest that the factors routine, stress, release, balance, and the previous play situation have a substantial impact on the score of the player's draw game. However, no factor has a statistically significant impact on the average distance to the center of the target. Moreover, the DoE analysis also concludes that the accuracy and precision of the player's performance is not affected equally by all analyzed factors, but they turn into highly significant when examining their relationship to the other factors. Practical implications The findings of this study can be beneficial to other sports events in improving the performance. Moreover, DoE has proved to be an invaluable tool for many people in the German Curling Association in understanding the factors which influence the curlers performance and also factors which do not affect the curlers performance. Originality/value This research attempts to contribute to the existing sports management literature by identifying a way in which DoE can be an effective tool in non-manufacturing settings for identification of most important factors which influence the curling performance.

One aspect of Walter Benjamin’s approach that can undoubtedly be described as visionary is the high value he accorded film among the arts. Today time-based, audiovisual media is viewed as an integral and extraordinarily important part of the art system, but when Benjamin’s essay “The Work of Art in the Age of Its Technological Reproducibility” was enthusiastically rediscovered in the 1960s, this was by no means the case. Video artists of the first generation had to fight for recognition, and Benjamin’s writings matched their goals. This essay gets to the basis of the connection between media art and the figure of Walter Benjamin, examining his art- and media-related reflections, subjecting them to a critical examination, and at the same time attempting to make them productive for our understanding of contemporary conditions.

The MSU Library Seed Library is a publicly accessible place to pick-up some seeds for vegetable, herb and flower growing. You can learn about growing seeds, resources on starting seeds, books on gardening, soil preparation, garden miscellany, and yard conversion.

High-frequency transport in the edge states of the quantum spin Hall (QSH) effect has rarely been explored, though it could cast light on the scattering mechanisms taking place therein. Here we report on the measurement of the plasmon velocity in topological HgTe quantum wells both in the QSH and quantum Hall (QH) regimes, using harmonic GHz excitations and phase-resolved detection. We observe low plasmon velocities in both regimes, with, in particular, large transverse widths in the QH regime despite a sharp edge confinement profile. We ascribe these observations to the prominent influence of charge puddles forming in the vicinity of edge channels. Together with other recent works, it suggests that puddles play an essential role in the edge state physics and probably constitute a main hurdle on the way to clean and robust edge transport.

We utilize a diffusion-controlled wet chemical etching technique to fabricate microstructures from two-dimensional HgTe/(Hg,Cd)Te-based topological insulators. For this purpose, we employ a KI: I2: HBr: H2O-based etchant. Investigation of the side profile of the etched heterostructure reveals that HgTe quantum wells protrude from the layer stack as a result of the different etch rates of the layers. This constraint poses challenges for the study of the transport properties of edge channels in HgTe quantum wells. In order to achieve a smoother side profile, we develop a novel approach to the etching process involving the incorporation of a sacrificial design element in the etch mask. This limits the flow of charge carriers to the ions in the electrolyte during the etching process. The simplicity of the method coupled with the promising results achieved thereby should make it possible for the new approach introduced here to be applied to other semiconductor heterostructures.

Fluctuations in planar magnetotransport are ubiquitous in topological HgTe structures, in both tensile (topological insulator) and compressively strained layers (Weyl semimetal phase). We show that the common reason for the fluctuations is the presence of tilted Dirac cones combined with the formation of charge puddles. The origin of the tilted Dirac cones is the mix of the Zeeman term due to the in-plane magnetic field and quadratic contributions to the dispersion relation. We develop a network model that mimics the transport of tilted Dirac fermions in the landscape of charge puddles. The model captures the essential features of the experimental data. It should be relevant for the interpretation of planar magnetotransport in a variety of topological and small band gap materials.

Nonlinear phenomena in the THz spectral domain are important for understanding the optoelectronic properties of quantum systems and provide a basis for modern information technologies. Here, we report a giant THz nonlinearity in high-mobility 2D topological insulators based on HgTe quantum wells, which manifests itself in a highly efficient third harmonic generation. We observe a third harmonic THz susceptibility several times higher than that in bare graphene and many orders of magnitude higher than that in trivial quantum well structures based on other materials. To explain the strong nonlinearity of HgTe-based heterostructures at the THz frequencies, we consider the acceleration of free carriers with a high mobility and variable dispersion. This acceleration model, for which the nonparabolicity of the band dispersion is key, in combination with independently measured scattering time and conductivity, is in good agreement with our experimental data in a wide temperature range for THz fields below the saturation. Our approach provides a route to material engineering for THz applications based on frequency conversion.

Under time-reversal symmetry, quantum spin Hall edge channels are protected against elastic backscattering. However, even for samples which exhibit conductance quantization due to the quantum spin Hall effect, reproducible fluctuations shape the quantization plateau when the chemical potential is tuned through the bulk gap. Here, we examine those fluctuations in micron-sized HgTe quantum well devices. By performing temperature- and gate-dependent measurements, we conclude that “charge puddles” in the narrow-gap material have a Kondo-type interaction with the edge channels resulting in the observed conductance fluctuations. Our results provide insight into the underlying mechanisms of scattering in quantum spin Hall edge channels.

Introduction Infections have been linked to damaged or contaminated endoscopes with visible defects. Endoscope processing standards and guidelines state endoscopes should be visually inspected every time they are used. This study evaluated a new visual inspection program using magnification and borescopes in an endoscopy department that had not previously utilized these tools. Methods Site personnel were given visual inspection tools and training before systematically examining fully processed endoscopes twice during a 2-month period. A risk assessment protocol was used to determine whether endoscopes required recleaning, repair, or other action. Findings were documented using log sheets, photographs, and videotapes. Results Visible damage and residue or debris were observed in 100% of 25 endoscopes at both assessments, and 76% required repair. Defects at baseline included scratches (88%); channel shredding or peeling (80%); adhesive band disintegration (80%); residual soil or debris (white 84%; black 68%; brown 40%; yellow/green 36%; and orange/red 8%); retained fluid (52%); and dents (40%). Findings were similar at follow-up. Discussion/Conclusions Visual inspection with magnification and borescopes identified actionable defects that could interfere with processing effectiveness in 100% of endoscopes. Infection preventionists have a critical role to play in supporting processing personnel now that standards, guidelines, and manufacturer instructions recommend enhanced visual inspection of every endoscope, every time.

In the domain of graph neural networks (GNNs), pooling operators are fundamental to reduce the size of the graph by simplifying graph structures and vertex features. Recent advances have shown that well-designed pooling operators, coupled with message-passing layers, can endow hierarchical GNNs with an expressive power regarding the graph isomorphism test that is equal to the Weisfeiler-Leman test. However, the ability of hierarchical GNNs to increase expressive power by utilizing graph coarsening was not yet explored. This results in uncertainties about the benefits of pooling operators and a lack of sufficient properties to guide their design. In this work, we identify conditions for pooling operators to generate WL-distinguishable coarsened graphs from originally WL-indistinguishable but non-isomorphic graphs. Our conditions are versatile and can be tailored to specific tasks and data characteristics, offering a promising avenue for further research.

Continuous Kernels have been a recent development in convolutional neural networks. Such kernels are used to process data sampled at different resolutions as well as irregularly and inconsistently sampled data. Convolutional neural networks have the property of translational invariance (e.g., features are detected regardless of their position in the measurement domain), which is unsuitable if the position of detected features is relevant for the prediction task. However, the capabilities of continuous kernels to process irregularly sampled data are still desired. This article introduces the continuous feature network, a novel method utilizing continuous kernels, for detecting global features at absolute positions in the data domain. Through a use case in processing multiple spatially resolved reflection spectroscopy data, which is sampled irregularly and inconsistently, we show that the proposed method is capable of processing such data directly without additional preprocessing or augmentation as is needed using comparable methods. In addition, we show that the proposed method is able to achieve a higher prediction accuracy than a comparable network on a dataset with position-dependent features. Furthermore, a higher robustness to missing data compared to a benchmark network using data interpolation is observed, which allows the network to adapt to sensors with a failure of individual light emitters or detectors without the need for retraining. The article shows how these capabilities stem from the continuous kernels used and how the number of available kernels to be trained affects the model. Finally, the article proposes a method to utilize the introduced method as a base for an interpretable model usable for explainable AI.

Ornithischian dinosaurs exhibited a diversity of ecologies, locomotory modes, and social structures, making them an ideal clade in which to study the evolution of neuroanatomy and behaviour. Here, we present a 3D digital reconstruction of the endocranial spaces of the latest Cretaceous neornithischian Thescelosaurus neglectus, in order to interpret the neuroanatomy and paleobiology of one of the last surviving non-avian dinosaurs. Results demonstrate that the brain of Thescelosaurus was relatively small compared to most other neornithischians, instead suggesting cognitive capabilities within the range of extant reptiles. Other traits include a narrow hearing range, with limited ability to distinguish high frequencies, paired with unusually well-developed olfactory lobes and anterior semicircular canals, indicating acute olfaction and vestibular sensitivity. This character combination, in conjunction with features of the postcranial anatomy, is consistent with specializations for burrowing behaviours in the clade, as evidenced by trace and skeletal fossil evidence in earlier-diverging thescelosaurids, although whether they reflect ecological adaptations or phylogenetic inheritance in T. neglectus itself is unclear. Nonetheless, our results provide the first evidence of neurological specializations to burrowing identified within Ornithischia, and non-avian dinosaurs more generally, expanding the range of ecological adaptations recognized within this major clade.

This essay outlines a program for updating German media studies by reformatting, repartitioning, and potentially rebooting German media theory. As a temporary placeholder, German media studies 2.0 describes current transatlantic research committed to fixing bugs and patching vulnerabilities that emerged from historical encounters between media and critique, ideology and epistemology, and the Frankfurt School and the Kittler Network. To update German media studies in a critical mode, we need to keep defining our concepts and delimiting our disciplines, accounting for the effects of media change on our research methods, and negotiating our field’s complex relations to culture, history, and politics.

This article examines the 1910s media pedagogy of Dr. Lillian Gilbreth, industrial psychologist and collaborator of Frank Gilbreth in the development of motion study. Intending to reconcile the incongruities between workers and modern machines, Lillian drew on the psychology of William James to devise the theoretical grounds for the Gilbreths' production and use of moving images. The essay shows how Lillian Gilbreth positioned film as an interactive medium, directing experimental exhibition practices that instantiated mimesis among spectators; treated features of bodily difference as individually addressable and serviceable to productivity; and exploited the human body's predisposition for habituation, and therefore predictability.

This article explores the topic of technology in Michel Serres’ work. Although a great deal has been said about Serres’ treatment of parasitic relations, noise, interdisciplinarity and communication, little has been written about his approach to questions of technology. The author first outlines general trends in the philosophy of technology and indicates how Serres fits within the field. He then suggests a way to read Serres by identifying ‘landmarks’ in his texts, which are used for explicating his position on technology. Three of these landmarks are explored. The first is Serres’ philosophy of world-objects, which moves him to think through the relationship between humans, technology and natural evolution. The second is Serres’ notion of technologies ‘setting sail’ from the body, which allows him to build on Leroi-Gourhan’s work, and the third is Serres’ description of information technologies and the world of millennials, which leads to his position on pedagogy and technology. From an examination of these three landmarks, a picture emerges of a thinker for whom technology acts as a disturbance around which collectives form, establishing relations and deviations between ourselves and others.

The COVID-19 pandemic resulted in substantial international scientific research from high-income countries, with fewer contributions from low- and middle-income countries (LMIC). Utilizing a field theory approach, we contend that these output variations may underscore challenges faced by LMIC researchers in obtaining international academic recognition. Through a systematic review of Brazilian and international Communication research during the pandemic, we identify differences in research interests, constructs, methods, and use of academic references. While international literature prioritizes quantitative surveys, Brazil emphasizes qualitative content analysis. We also observe dissimilarities in covered topics and a limited number of shared references. Research traditions and distinct resource allocations pose additional barriers to international publishing, hampering academic exchanges between these communities.

New media and new applications of existing media are typically seen as ways of distributing knowledge more effectively, often with hopes that this process will strengthen democracy. Adopting a history-of-knowledge approach, the authors analyze methods of knowledge circulation attending early print, nineteenth-century mechanics’ institutes and public libraries, early radio broadcasting, and explanatory journalism, providing a comparative historical framework for a recent new-media platform for distributing knowledge, The Conversation network. Appealing to a socially broad audience has consistently been a challenge. Efforts to distribute knowledge also reflected differences in prevailing media ecosystems, national systems of political economy, and contemporary social/political concerns.

Since the nineteenth-century devolution of natural philosophy into disciplines, scientific activity has expanded from single-disciplined research to comprehensive research. The flow of information between different research teams makes scientific research and its places increasingly social, which is no longer limited to the closed laboratory workbench. Reviewing the literature, we found that the development of scientific research buildings experienced a transition from efficiency to openness. And the new organization of research communities and its demand for space put forward higher requirements for scientific research buildings. To deeply explore the design trends of scientific research buildings at this stage, the sample database is established using space syntax and K-means clustering algorithm software to quantitatively analyze spatial layouts of 42 scientific research buildings worldwide from the perspective of sociology and innovation, clustered into five categories. Each category shows a different tendency in terms of accessibility, visibility, and the proportion of public space, and the different spatial configurations and openness somehow reflect the attitude of the research organization or group towards the use of space.

"Les Bamanan ne font pas de différence fondamentale entre jeu et manifestation sérieuse. L'animateur de marionnettes ne se laissera pas emporter par le côté ludique de son rôle, il s'y attachera avec sérieux et dévouement en vue de créer un plaisir sain chez les spectateurs. L'adage populaire dit que l'amusement n'empêche pas le sérieux : « toute personne susceptible de te dépasser dans le jeu est à coup sûr en mesure de te surpasser dans d'autres domaines plus sérieux ». Ainsi par exemple, lorsque le village de Tiongoni, dans le cercle de Ségou, organise son spectacle de marionnettes, il invite les différentes associations de jeunes des villages environnants qui envoient donc des représentants." (https://www.editions-harmattan.fr/livre-marionnettes_et_theatre_de_marionettes_au_mali_cheick_oumar_mara-9782140337710-76401.html)

Wie sieht Ihre grüne Bibliothek von morgen aus? Welche Ideen und Visionen würden bei dieser Frage spontan bei Ihnen im Kopf entstehen? Unstrittig ist bei dieser Frage sicherlich: Es arbeiten weiterhin Menschen in der Bibliothek, die die Werte und Normen der Institution vertreten und leben. Diverse Bibliotheksteams bringen Vielfalt, Offenheit und Toleranz in das Bild von den Menschen, die in Bibliotheken arbeiten und wirken. Eine sehr bedeutsame Berufsgruppe dieser Menschen in Bibliotheken sind die Fachangestellten für Medien- und Informationsdienste, kurz FaMI. Deren duale Ausbildung gibt es nun seit 25 Jahren und in Zeiten von Fachkräftemangel geht es mehr denn je darum, die Bibliothek als authentische Ausbildungsstätte und als attraktiven Arbeitgeber zu vermitteln. Die Merkmale einer glqqGrünen Bibliothekgrqq und die Aufgabe von Bibliotheken, sich proaktiv an der sozial-ökologischen Transformation zu beteiligen, spielt für die Autorin - Ausbilderin und Trainerin im Bereich Bildung für nachhaltige Entwicklung (BNE) - eine entscheidende Rolle.

We present a setup for fast, low-bias (< 1 mV) DC transport measurements with μs time resolution for high ohmic resistance (~ 20 kΩ) semiconducting samples.We discuss the circuitry and instrumentation for the measurement approach that can be applied to any kind of semiconductor device or (gated) two-dimensional material and demonstrate the main measurement artifacts in typical measurements by means of circuit simulation. Based on the latter, we present a simple two-step protocol for eliminating the measurement artifacts reliably. We demonstrate the technique by measuring the transitions between quantum Hall plateaus in the HgTe quantum wells and resolve plateaus as short-lived as 100 μs.

Uncertainty becomes the new normal for organizations worldwide. Many organizations are dependent on complex global supply chains. COVID-19, but also environmental disasters or the war in Ukraine, demonstrate the volatility of supply chains. Procurement departments are the central interface between internal and external stakeholders and must manage the supply chain stability what requires fast and accurate decision-making. External shocks and sudden disruptions of central supply chains illustrated that data analytics could not prevent disruptions, although sound research on competitive advantages and numerous investments should have enabled organizations to data-driven decision-making. Rather, it became transparent, that there are numerous data deficits in organizations. We did an interview-based study with 23 procurement and supply chain experts about relevant data sets and the status of its usability. We contribute to theory and practice by uncovering relevant aspects of data and provide theoretical propositions on how decision-making can be improved in automotive procurement departments.

Abstract: Cover song identification (CSI) focuses on finding the same music with different versions in reference anchors given a query track. In this paper, we propose a novel system named CoverHunter that overcomes the shortcomings of existing detection schemes by exploring richer features with refined attention and alignments. CoverHunter contains three key modules: 1) A convolution-augmented transformer (i.e., Conformer) structure that captures both local and global feature interactions in contrast to previous methods mainly relying on convolutional neural networks; 2) An attention-based time pooling module that further exploits the attention in the time dimension; 3) A novel coarse-to-fine training scheme that first trains a network to roughly align the song chunks and then refines the network by training on the aligned chunks. At the same time, we also summarize some important training tricks used in our system that help achieve better results. Experiments on several standard CSI datasets show that our method significantly improves over state-of-the-art methods with an embedding size of 128 (2.3% on SHS100K-TEST and 17.7% on DaTacos).

Fracture surface analysis is of utmost importance with respect to structural integrity of metallic materials. This especially holds true for additively manufactured materials. Despite an increasing trend of automatization of testing methods, the analysis and classification of fatigue fracture surface images is commonly done manually by experts. Although this leads to correct results in most cases, it has several disadvantages, e.g., the need of a huge knowledge base to interpret images correctly. In present work, an unsupervised tool for analysis of overview images of fatigue fracture surface images is developed to support nonexperienced users to identify the origin of the fracture. The tool is developed using fracture surface images of additively manufactured Ti6Al4V specimens fatigued in the high-cycle-fatigue regime and is based on the identification of river marks. Several recording parameters seem to have no significant influence on the results as long as preprocessing settings are adapted. Moreover, it is possible to analyze images of other materials with the tool as long as the fracture surfaces contain river marks. However, special features like multiple origins or origins located in direct vicinity to the surface, e.g., caused by increased plastic strains, require a further tool development or alternative approaches.

Despite considerable research on pool-based deep active learning (DAL), deploying DAL into real applications still has several challenges. A frequently neglected aspect is the choice of training hyperparameters (HPs), such as the learning rate. Since these HPs determine how the deep neural network learns in each cycle, they must be chosen carefully. In this article, we analyze the role of HPs in DAL. We find that optimizing HPs reduces the performance gap between DAL strategies. Conversely, we highlight challenges in finding optimal HPs when using datasets selected via DAL strategies.

We show that the rainbow state, which has volume-law entanglement entropy for most choices of bipartitions, can be embedded in a many-body localized spectrum. For a broad range of disorder strengths in the resulting model, we numerically find a narrow window of highly entangled states in the spectrum, embedded in a sea of area law entangled states. The construction hence embeds mobility edges in many-body localized systems. This can be thought of as the complement to many-body scars, an “inverted quantum many-body scar,” providing a further type of setting where the eigenstate thermalization hypothesis is violated.

Exceptional points are degeneracies in the spectrum of non-Hermitian open systems where at least two eigenfrequencies and simultaneously the corresponding eigenstates of the Hamiltonian coalesce. Especially, the robust construction of higher-order exceptional points with more than two degenerate eigenfrequencies and eigenstates is challenging but yet worthwhile for applications. In this paper, we reconsider the formation of higher-order exceptional points through waveguide-coupled microring cavities and asymmetric backscattering. In this context, we demonstrate the influence of perturbations on the frequency splitting of the system. To generate higher-order exceptional points in a simple and robust way, a mirror-induced asymmetric backscattering approach is used. In addition to the exceptional-point enhanced sensing capabilities of such systems, also a cavity-selective sensitivity is achieved for particle sensing. The results are motivated by an effective Hamiltonian description and verified by full numerical simulations of the dielectric structure.

The crystal family of potassium titanyl phosphate (KTiOPO4) is a promising material group for applications in quantum and nonlinear optics. The fabrication of low-loss optical waveguides, as well as high-grade periodically poled ferroelectric domain structures, requires a profound understanding of the material properties and crystal structure. In this regard, Raman spectroscopy offers the possibility to study and visualize domain structures, strain, defects, and the local stoichiometry, which are all factors impacting device performance. However, the accurate interpretation of Raman spectra and their changes with respect to extrinsic and intrinsic defects requires a thorough assignment of the Raman modes to their respective crystal features, which to date is only partly conducted based on phenomenological modelling. To address this issue, we calculated the phonon spectra of potassium titanyl phosphate and the related compounds rubidium titanyl phosphate (RbTiOPO4) and potassium titanyl arsenate (KTiOAsO4) based on density functional theory and compared them with experimental data. Overall, this allows us to assign various spectral features to eigenmodes of lattice substructures with improved detail compared to previous assignments. Nevertheless, the analysis also shows that not all features of the spectra can unambigiously be explained yet. A possible explanation might be that defects or long range fields not included in the modeling play a crucial rule for the resulting Raman spectrum. In conclusion, this work provides an improved foundation into the vibrational properties in the KTiOPO4 material family.

We show how geometric phases may be used to fully describe quantum systems, with or without gravity, by providing knowledge about the geometry and topology of its Hilbert space. We find a direct relation between geometric phases and von Neumann algebras. In particular, we show that a vanishing geometric phase implies the existence of a well-defined trace functional on the algebra. We discuss how this is realised within the AdS/CFT correspondence for the eternal black hole. On the other hand, a non-vanishing geometric phase indicates missing information for a local observer, associated to reference frames covering only parts of the quantum system considered. We illustrate this with several examples, ranging from a single spin in a magnetic field to Virasoro Berry phases and the geometric phase associated to the eternal black hole in AdS spacetime. For the latter, a non-vanishing geometric phase is tied to the presence of a centre in the associated von Neumann algebra.

Biofilms are communities of microorganisms that grow on virtually all surfaces with sufficient nutrients including aquatic and industrial water systems and medical devices. Biofilms are complex, structured communities where the interplay of growth, metabolism, and competition between species interact with physical processes of diffusion, convection, attachment, and detachment. This work describes a model of a one-dimensional biofilm in a stirred tank reactor that incorporates these complexities. The model is implemented in the modern Julia programming language providing an efficient tool for studying a large variety of biofilms and the intricate communities the microorganisms create. Details of the new software, known as Biofilm.jl, including the mathematical model and organization and execution of the code, are provided. Examples of biofilms modeled using Biofilm.jl are presented such as a single heterotroph, sulfide-oxidizing bacteria (SOB) and sulfate-reducing bacteria (SRB), and a phototroph. Postprocessing tools are described that allow a Biofilm.jl user to make plots and extract specific values from the solution and explore the simulated biofilm results. Program summary Program Title: Biofilm.jl CPC Library link to program files: https://doi.org/10.17632/n8sgj48nvd.1 Developer's repository link: https://github.com/markowkes/Biofilm.jl Code Ocean capsule: https://codeocean.com/capsule/2341966 Licensing provisions: MIT Programming language: Julia (Developed on v1.8, tested on v1.9) Supplementary material: https://markowkes.github.io/Biofilm.jl Nature of problem: This software solves for the temporal and spatial dynamics of an arbitrary number of solutes and particulates (biomass species) in a one-dimensional biofilm. The model includes the growth of particulates and the associated solute consumption (or production), the biofilm thickness dynamics due to growth within and detachment from the top of the biofilm. Additionally, source terms can be used to model the death of biomass or other effects. Discontinuous inputs, such as the diurnal cycle or periodic dosing, can be included. Solution method: The software solves for the temporal dynamics of particulates, solutes, and biofilm thickness, which are described by differential equations. These equations are discretized using a finite volume method and organized into a single system of ordinary differential equations that are solved using the DifferentialEquations.jl library. The software includes a collection of postprocessing tools to assist the user with exploring the simulation results.

Establishing suitable design strategies to tailor the functional properties of perylene bisimide (PBI) dyes is critical for their successful application in various devices. Herein, we report a new synthetic strategy to tune their structural and fluorescence properties by employing a 1,12-bay-substitution pattern that has been seldomly investigated in the past. Central to the strategy is the use of 1, 12-dihydroxy-PBI as a starting compound and the subsequent bridging of these hydroxy bay-functional groups with either a boron, carbon or silicon atom resulting in derivatives with a rigidified perylene core. This is followed by a detailed exploration of synthetic possibilities to functionalize the unsubstituted 6,7-positions at the opposite bay area to achieve novel perylene dyes with excellent structural and optical properties. The fluorescence color could be tuned from green to dark-orange while retaining the almost unity fluorescence quantum yield in solution. Moreover, a strong fluorescence with quantum yields as high as 40% has been observed for powders, which clearly illustrates the potential of the presented structural design to obtain new solid-state emitters.

Previous studies show that city metrics having to do with growth, productivity and overall energy consumption scale superlinearly, attributing this to the social nature of cities. Superlinear scaling results in crises called ‘singularities’, where population and energy demand tend to infinity in a finite amount of time, which must be avoided by ever more frequent ‘resets’ or innovations that postpone the system's collapse. Here, we place the emergence of cities and planetary civilizations in the context of major evolutionary transitions. With this perspective, we hypothesize that once a planetary civilization transitions into a state that can be described as one virtually connected global city, it will face an ‘asymptotic burnout’, an ultimate crisis where the singularity-interval time scale becomes smaller than the time scale of innovation. If a civilization develops the capability to understand its own trajectory, it will have a window of time to affect a fundamental change to prioritize long-term homeostasis and well-being over unyielding growth—a consciously induced trajectory change or ‘homeostatic awakening’. We propose a new resolution to the Fermi paradox: civilizations either collapse from burnout or redirect themselves to prioritizing homeostasis, a state where cosmic expansion is no longer a goal, making them difficult to detect remotely.

We determine the proper motion of the Solar System from the Pantheon sample of type Ia supernovae (SNe). The posterior distribution of the Solar System proper velocity, its direction, and relevant cosmological parameters were obtained based on the observed distance moduli, heliocentric redshifts, and positions of SNe by means of a Markov chain Monte Carlo method. We accounted for the unknown peculiar motion of SNe by including their expected covariance from linear theory. We find that the Solar System moves with vo = 249 ± 51 km s−1 towards RA = 166 ± 16 deg, Dec = 10 ± 19 deg (J2000), (all at 68% C.L.). The direction of motion agrees with the direction of the dipole observed in the cosmic microwave background (CMB) (RA = 166 deg, Dec = −7 deg). The inferred velocity is 2.4σ lower than the value inferred from a purely kinematic interpretation of the CMB dipole (370 km s−1). Assuming a flat Λ cold dark matter model, we find no degeneracy of solar proper motion with other cosmological parameters. The dimensionless matter density, ΩM = 0.305 ± 0.022, is in excellent agreement with CMB measurements. We also find no degeneracy of the solar proper motion with the SN calibration nuisance parameter. Bulk flows might be able to explain why the solar motion appears to be slower than that of nearby SNe. We conclude that a larger sample of SNe, distributed over wide areas of the sky and a broad range in redshift, will allow an independent and robust test of the kinematic nature of the CMB dipole.

Polygenic adaptation is thought to be ubiquitous, yet remains poorly understood. Here, we model this process analytically, in the plausible setting of a highly polygenic, quantitative trait that experiences a sudden shift in the fitness optimum. We show how the mean phenotype changes over time, depending on the effect sizes of loci that contribute to variance in the trait, and characterize the allele dynamics at these loci. Notably, we describe the two phases of the allele dynamics: The first is a rapid phase, in which directional selection introduces small frequency differences between alleles whose effects are aligned with or opposed to the shift, ultimately leading to small differences in their probability of fixation during a second, longer phase, governed by stabilizing selection. As we discuss, key results should hold in more general settings and have important implications for efforts to identify the genetic basis of adaptation in humans and other species.

Genome-wide association studies have revealed that the genetic architectures of complex traits vary widely, including in terms of the numbers, effect sizes, and allele frequencies of significant hits. However, at present we lack a principled way of understanding the similarities and differences among traits. Here, we describe a probabilistic model that combines mutation, drift, and stabilizing selection at individual sites with a genome-scale model of phenotypic variation. In this model, the architecture of a trait arises from the distribution of selection coefficients of mutations and from two scaling parameters. We fit this model for 95 diverse, highly polygenic quantitative traits from the UK Biobank. Notably, we infer similar distributions of selection coefficients across all these traits. This shared distribution implies that differences in architectures of highly polygenic traits arise mainly from the two scaling parameters: the mutational target size and heritability per site, which vary by orders of magnitude across traits. When these two scale factors are accounted for, the architectures of all 95 traits are nearly identical.Competing Interest StatementThe authors have declared no competing interest.

Machine learning-based modeling of physical systems has experienced increased interest in recent years. Despite some impressive progress, there is still a lack of benchmarks for Scientific ML that are easy to use but still challenging and representative of a wide range of problems. We introduce PDEBench, a benchmark suite of time-dependent simulation tasks based on Partial Differential Equations (PDEs). PDEBench comprises both code and data to benchmark the performance of novel machine learning models against both classical numerical simulations and machine learning baselines. Our proposed set of benchmark problems contribute the following unique features: (1) A much wider range of PDEs compared to existing benchmarks, ranging from relatively common examples to more realistic and difficult problems; (2) much larger ready-to-use datasets compared to prior work, comprising multiple simulation runs across a larger number of initial and boundary conditions and PDE parameters; (3) more extensible source codes with user-friendly APIs for data generation and baseline results with popular machine learning models (FNO, U-Net, PINN, Gradient-Based Inverse Method). PDEBench allows researchers to extend the benchmark freely for their own purposes using a standardized API and to compare the performance of new models to existing baseline methods. We also propose new evaluation metrics with the aim to provide a more holistic understanding of learning methods in the context of Scientific ML. With those metrics we identify tasks which are challenging for recent ML methods and propose these tasks as future challenges for the community. The code is available at https://github.com/pdebench/PDEBench.

In the machine learning and data science pipelines, feature extraction is considered the most crucial component according to researchers, where generating a discriminative feature matrix is the utmost challenging task to achieve high classification accuracy. Generally, the classical feature extraction techniques are sensitive to the noisy component of the signal and need more time for training. To deal with these issues, a comparatively new feature extraction technique, referred to as a wavelet scattering transform (WST) is utilized, and incorporated with ML classifiers to design a framework for bearing fault classification in this paper. The WST is a knowledge-based technique, and the structure is similar to the convolution neural network. This technique provides low-variance features of real-valued signals, which are usually necessary for classification tasks. These signals are resistant to signal deformation and preserve information at high frequencies. The current signal data from a publicly available dataset for three different bearing conditions are considered. By combining the scattering path coefficients, the decomposition coefficients from the 0th and 1st layers are considered as features. The experimental results demonstrate that WST-based features, when used with ensemble ML algorithms, could achieve more than 99% classification accuracy. The performance of ANN models with these features is similar. This work exhibits that utilizing WST coefficients for the motor current signal as features can improve the bearing fault classification accuracy when compared to other feature extraction approaches such as empirical wavelet transform (EWT), information fusion (IF), and wavelet packet decomposition (WPD). Thus, our proposed approach can be considered as an effective classification method for the fault diagnosis of rotating machinery.

Machine learning (ML) provides novel and powerful ways of accurately and efficiently recognizing complex patterns, emulating nonlinear dynamics, and predicting the spatio-temporal evolution of weather and climate processes. Off-the-shelf ML models, however, do not necessarily obey the fundamental governing laws of physical systems, nor do they generalize well to scenarios on which they have not been trained. We survey systematic approaches to incorporating physics and domain knowledge into ML models and distill these approaches into broad categories. Through 10 case studies, we show how these approaches have been used successfully for emulating, downscaling, and forecasting weather and climate processes. The accomplishments of these studies include greater physical consistency, reduced training time, improved data efficiency, and better generalization. Finally, we synthesize the lessons learned and identify scientific, diagnostic, computational, and resource challenges for developing truly robust and reliable physics-informed ML models for weather and climate processes. This article is part of the theme issue ‘Machine learning for weather and climate modelling’.

In current scholarship, Susanne Langer and her theories of art, perception and connectivity are less well known than McLuhan’s. Comparison brings to the fore that both were concerned with the dulling effects of heavy-handed science and technology unregulated by human hand and heart, and both understood the expressive and liberatory possibilities of language as media and metaphor. By reading ‘diffractively’ – finding new connections and honouring patterns over polemics – this article brings Langer back into the scholarly conversation and reinvigorates our understanding of McLuhan. Langer did not consider her thought as principled by feminism. Yet according to recent critical biographer Adrienne Dengerink Chaplin, her work was rooted in feminist ontology for espousing principles of relationality and embodiment. My article argues that McLuhan, too, eschewed dichotomies and linearities of traditional thought for the principle of relationality. Extending this claim further, my article also submits that media ecology – with its emphasis on interconnectivities, on feeling and thinking, on non-linearity – has features in common with feminist thinking.

" À la fin du XIXe siècle, dans toute l’Europe, les avant-gardes théâtrales font de la marionnette — jusqu’alors ancrée dans des traditions en déclin — un véritable modèle esthétique, qui persiste jusqu’à la fin des années trente. Ainsi, le sujet de ce livre n’est pas « le théâtre de marionnettes », défini par une série de pratiques qui volent alors en éclats, mais « la marionnette au théâtre » : comment et pourquoi cet objet théâtral entre-t-il dans le champ du « grand » théâtre, c’est-à-dire de la scène d’acteurs, et qu’y change-t-il ? Que devient la marionnette dans cette rencontre ? Ce « modèle marionnettique », profondément critique et expérimental, devient alors un laboratoire qui explore tous les champs de l’art du théâtre : théorie, dramaturgie, mise en scène. Cet ouvrage associe ces trois dimensions et analyse, dans trois pays où les conditions de la vie théâtrale sont assez différentes (la Belgique, l’Espagne et la France), à la fois des textes théoriques (manifestes, articles de presse), des réalisations scéniques et des textes dramatiques, en accordant une attention particulière au dernier aspect. De très nombreux textes dramatiques dits « pour marionnettes » ou inspirés par son esthétique y sont convoqués et soumis à une analyse dramaturgique approfondie qui explore la variété des possibilités dramatiques offertes par la marionnette au théâtre. On voit alors comment l’énergie polémique du modèle marionnettique explore, souvent avant l’heure, des territoires fondamentaux de la scène moderne : méta-théâtralité, parodie, distanciation, fusion des arts, mais aussi recherche d’un théâtre métaphysique, populaire et politique" (https://www.deuxiemeepoque.fr/index.php?id_product=29&controller=product&id_lang=3)

Human genome-wide association studies (GWASs) are revealing the genetic architecture of anthropomorphic and biomedical traits, i.e., the frequencies and effect sizes of variants that contribute to heritable variation in a trait. To interpret these findings, we need to understand how genetic architecture is shaped by basic population genetics processes—notably, by mutation, natural selection, and genetic drift. Because many quantitative traits are subject to stabilizing selection and because genetic variation that affects one trait often affects many others, we model the genetic architecture of a focal trait that arises under stabilizing selection in a multidimensional trait space. We solve the model for the phenotypic distribution and allelic dynamics at steady state and derive robust, closed-form solutions for summary statistics of the genetic architecture. Our results provide a simple interpretation for missing heritability and why it varies among traits. They predict that the distribution of variances contributed by loci identified in GWASs is well approximated by a simple functional form that depends on a single parameter: the expected contribution to genetic variance of a strongly selected site affecting the trait. We test this prediction against the results of GWASs for height and body mass index (BMI) and find that it fits the data well, allowing us to make inferences about the degree of pleiotropy and mutational target size for these traits. Our findings help to explain why the GWAS for height explains more of the heritable variance than the similarly sized GWAS for BMI and to predict the increase in explained heritability with study sample size. Considering the demographic history of European populations, in which these GWASs were performed, we further find that most of the associations they identified likely involve mutations that arose shortly before or during the Out-of-Africa bottleneck at sites with selection coefficients around s = 10−3.

"The Holden family were the most celebrated English marionette performers of the nineteenth century. The trajectory of the Holdens provides a vivid example of developments in entertainment across the century. Having begun on the fairgrounds, they moved on to large halls, theatres and music halls. At the height of their popularity, when they had two main companies in operation, the Holdens were even better known abroad than at home. Their name was almost synonymous with puppetry, and they were credited with every innovation in marionette theatre. Then, with the advent of cinema, their business suffered a rapid decline. Based on extensive archival research and lavishly illustrated with photographs, sketches, diagrams, playbills and posters, The Holdens: Monarchs of the Marionette Theatre explains why the Holden shows had such impact and were so frequently imitated." (https://www.str.org.uk/product/the-holdens-monarchs-of-the-marionette-theatre/)

"Le théâtre des marionnettes sur eau du Viêt Nam est un art millénaire encore trop peu connu aujourd'hui. Il s'agit d'un art né dans les rizières, transmis par de modestes paysans de génération en génération. Ce théâtre contient toute une mémoire historique et artistique qui s'enrichit et s'agrandit encore de nos jours. Alice Gaudry nous raconte la beauté de cet art, l'ingéniosité des mécanismes, la richesse des couleurs, les artifices et jets d'eau, tout participe à émerveiller le regard du spectateur." (https://www.editions-harmattan.fr/livre-le_theatre_de_marionnettes_sur_eau_du_viet_nam_jouer_avec_le_fluide_alice_gaudry-9782343031699-43119.html)

""Situé à la croisée des domaines de l'art, de l'artisanat et de la technique, vecteur de pratiques religieuses et de la culture populaire autant que de recherches esthétiques proprement dites, l'art de la marionnette déborde de toutes parts le carcan des imaginaires collectifs qu'elle mobilise. En étudiant son rôle et ses avatars au cours de l'histoire et dans les sociétés contemporaines, conservateurs, historiens de l'art et du spectacle, anthropologues et artistes interrogent ce champ irréductible à sa seule matérialité. Comment un tel objet a-t-il réussi à entrer dans les musées et de quelle manière lui octroyer la place qu'il mérite dans ce nouvel espace ? La question du statut de la marionnette, au-delà du champ patrimonial, est au coeur de cet ouvrage qui nous dévoile tous les secrets de ce théâtre du monde en réduction." (https://hal.parisnanterre.fr/hal-01650340)

In the field of tribology, the wear behaviour of polymers and composite materials is considered a highly non-linear phenomenon. Wear of Polymers and Composites introduces fundamentals of polymers and composites tribology. The book suggests a new approach to explore the effect of applied load and surface defects on the fatigue wear behaviour of polymers, using a new tribometer and thorough experiments. It discusses effects of surface cracks, under different static and cyclic loading parameters on wear, and presents an intelligent algorithm, in the form of a neural network, to map the relationship between wear rate and relevant factors. Using the aforementioned method leads to more accurate and cost effective prediction of surface fatigue wear rates, under different service conditions. The first three chapters of the book introduce polymers and composite materials tribology, followed by three chapters that cover testing in wear, applied load and contact pressure and surface defects. The remaining chapter moves on to predicting wear of polymers, and concludes by discussing questions and problems.

Aging affects functional connectivity between brain areas, however, a complete picture of how aging affects integration of information within and between functional networks is missing. We used complex network measures, derived from a brain-wide graph, to provide a comprehensive overview of age-related changes in functional connectivity. Functional connectivity in young and older participants was assessed during resting-state fMRI. The results show that aging has a large impact, not only on connectivity within functional networks but also on connectivity between the different functional networks in the brain. Brain networks in the elderly showed decreased modularity (less distinct functional networks) and decreased local efficiency. Connectivity decreased with age within networks supporting higher level cognitive functions, that is, within the default mode, cingulo-opercular and fronto-parietal control networks. Conversely, no changes in connectivity within the somatomotor and visual networks, networks implicated in primary information processing, were observed. Connectivity between these networks even increased with age. A brain-wide analysis approach of functional connectivity in the aging brain thus seems fundamental in understanding how age affects integration of information.

"In order to give shape, on stage, to the mysterious, joyous, and superbly complete life which is called Death , Craig proposed, in 1908, to replace the flesh-and-blood actor with an artificial double, the Über-marionette. Nearly seventy years later, Tadeusz Kantor, who had the mannequin enter the stage in the company of the living actor, aimed at reminding us that the art of theatre has its source in the territories of death. Today there are many artists who seize on these two legacies, pushing back the limits of the theatre of actors and puppet theatre in order to explore the links between the biological body and the artificial body, between the representation of the death and the representation of the living. This volume which comprises the proceedings of an international conference organized by the Institut international de la marionnette from 15-17 March 2012 brings together researchers, academics and artists from all over the world. Through the diversity of the evoked creators mentioned here (from Oskar Schlemmer to Gisèle Vienne, from Maurice Maeterlinck to Bérangère Vantusso, from Romeo Castellucci to Kris Verdonck, or from Virgilio Sieni to David Girondin-Moab or Oriza Hirata, etc.), the fascination for a theatre of effigies, where in which the signs of the life and the death are exchanged, is thus examined in its most recent developments, from an esthetic, poetic, philosophical or anthropological point of view.''

"African Theatres & Performances looks at four specific performance forms in Africa and uses this to question the tendency to employ western frames of reference to analyze and appreciate theatrical performance. The book examines: masquerade theatre in Eastern Nigeria the trance and possession ritual theatre of the Hausa of Northern Nigeria the musical and oral tradition of the Mandinka of Senegal comedy and satire of the Bamana in Mali. Osita Okagbue describes each performance in detail and discusses how each is made, who it is made by and for, and considers the relationship between maker and viewer and the social functions of performance and theatre in African societies. The discussions are based on first-hand observation and interviews with performers and spectators. African Theatres & Performances gives a fascinating account of these practices, carefully tracing the ways in which performances and theatres are unique and expressive of their cultural context." https://www.routledge.com/African-Theatres-and-Performances/Okagbue/p/book/9780415540858

This essay explores the development of media and visual culture studies in the larger context of American Studies in Germany. Even though research on media related topics and on visuality has proliferated in the past two decades, I argue there is need for further discussion about its place and practice within American Studies. In the following remarks I touch upon questions of institutional networks, the relation between the concept of culture and media technologies, canon revisions, the pedagogy of media and visual culture topics, and the competing claims of empirical and interpretative approaches. I wish to suggest that further theoretical and methodological debate could strengthen and diversify the growing interest in visual and media studies.

"L'art de l'Afrique noire est surtout présent à travers les masques. Ceux-ci étaient portés lors des cérémonies les plus importantes de la vie : initiation, funérailles. Dans cet ouvrage, les masques sont classés non en fonction de leur ethnie d'origine mais en fonction de l'animal qu'il représente (buffle, singe, oiseau, antilope, caïman, éléphant, fauve, etc.). Chaque pièce présentée est soigneusement décrite et son usage est expliqué, constituant une approche très originale et très accessible de l'un des arts les plus appréciés mais souvent très méconnus d'Afrique noire." (https://www.editions-harmattan.fr/livre-masques_animaliers_d_afrique_noire_gabriel_massa_chantal_dewe-9782842801755-49459.html)

In this paper, we briefly review the progress made in the mathematical modeling of biofilms over the last 30 years. Biofilms constitute a spectrum of dynamical microorganisms, whose interaction with the surrounding environment and thereby induced dynamics dictates the complex properties of the living organism. Modeling of biofilms began with a low dimensional continuum description first based on kinematics and translational diffusions; later, more sophisticated microscopic dynamical mechanisms are introduced leading to the anomalous diffusion and dissipation encountered by various components in biofilms. Recently, biofilm and bulk fluid (or solvent) coupling has been investigated using discrete-continuum, multifluid and single fluid multicomponent models to treat the entire biofilm-bulk-fluid system either as a system consisting of various components whose dynamics exhibits different time scale or as a whole. We classify the models into roughly four classes: low-dimensional continuum models, diffusion limited aggregation models, continuum-discrete models, and fully coupled biofilm-fluid models. We will address some hybrid models that combine the ideas from the above categories and new computational protocols combining the existing computational tools for cell dynamics coupled with the discrete-continuum biofilm model.

Every student learns that the sensory cortex is used for processing sensation and the motor cortex is used for perceiving movement. However, in the real world, this may not always be so neatly arranged. Matyas et al. (p. 1240) have found that sensory and motor fields are specialized for different types of movement, such that in mice the motor cortex controlled the forward movement (protraction) of their whiskers and the sensory cortex controlled backwards movements (retraction) of whiskers. So if a whisker hits an object, then a reasonable first reaction might be a motor command for retraction. Similarly, the motor cortex stimulates protraction for more active exploration. Hence, the sensory cortex is also motor and the motor cortex is also sensory. In an ecological context, these combined reactions offer a repertoire useful for a mouse seeking food and shelter in a complex environment. Mouse whisker movements are controlled by both the sensory and motor cortex. Classical studies of mammalian movement control define a prominent role for the primary motor cortex. Investigating the mouse whisker system, we found an additional and equally direct pathway for cortical motor control driven by the primary somatosensory cortex. Whereas activity in primary motor cortex directly evokes exploratory whisker protraction, primary somatosensory cortex directly drives whisker retraction, providing a rapid negative feedback signal for sensorimotor integration. Motor control by sensory cortex suggests the need to reevaluate the functional organization of cortical maps.

Two-body free-abrasive wear behavior of polyethylene (PE) coatings, nylon1010 (PA1010) coatings, polyurethane (PU) coatings, and expoxy (EP) coatings was investigated. Abrasive wear tests were performed on a turnplate abrasive wear test machine JMM. Hardened and low-temperature tempered steel 45 was used as a reference material. The results shown that in abrasive wear resistance, the PU coatings are approximately 120%, about 5 times larger than the PE coatings and 3 times larger than the PA1010 coatings and the EP coatings, the EP coatings and the PA1010 coatings approach to 40%, and the PE coatings about 20% compared with the reference material (steel 45). Of all the tested polymer coatings, the PU coatings are the best, the PE coatings the worst, and the PA1010 coatings and the EP coatings intermediate. Wear morphologies of the polymer coatings were observed by scanning electron microscope (SEM). Main wear mechanisms of the tested polymer coatings include ploughing wear for the PE coatings and the PA1010 coatings, fatigue wear for the PU coatings and fatigue fracture as well as some brittle fracture and somewhat ploughing wear for the EP coatings.

Master Bond Inc., Hackensack, NJ has developed a new two component heat cured epoxy adhesive called EP45HTMed. This compound is durable, tough and resistant to exposure to thermal shock and many chemicals. It can withstand long-term exposure form -80°F to 500°F and has a glass transition temperature of >185°C. Adhesion to metals, glass, ceramics, wood, vulcanized rubber and many plastics is excellent. The cured system is a superb electrical insulator (Plate 1).

Summary:The field of tribology encompasses knowledge drawn from the disciplines of mechanical engineering, materials science, chemistry and physics. This book addresses the control of friction and wear; and places emphasis on describing various concepts for the benefit of non-specialists.

The performance of a variety of polymers when subjected to cavitation erosion, solid particle erosion, abrasion and sliding wear has been determined using laboratory facilities that simulate the conditions encountered in mining and industrial machinery. The modes by which the different polymers deteriorate under these various conditions are described.

A study has been made of the wear of the polymers, polytetrafluoroethylene, polypropylene, polyoxymethylene, high density polyethylene, poly(vinyl chloride), polyamide and poly(methyl methacrylate), during sliding against abrasive papers, polished steel and like polymer countersurfaces. With the exception of poly(methyl methacrylate) and, to a lesser extent, polytetrafluoroethylene, there is a reasonable correlation between the wear rate of the polymer against abrasive paper and an expression involving the ploughing component of friction, the hardness, the tensile strength and the elongation to failure of the polymer as measured in tensile tests. Adhesive wear rates for like-on-like sliding are approximately proportional to the abrasive wear rates against SiC abrasive papers, although the absolute values are about 105 times smaller. In the wear process, material is drawn from the polymer surfaces, producing wear debris in the form of sheets or layers. Such debris may contain cracks or flaws and become further fragmented or compacted together to form aggregates.

People routinely develop their own theories to explain the world around them. These theories can be useful even when they contradict conventional technical wisdom. Based on in-depth interviews about home heating and thermostat setting behavior, the present study presents two theories people use to understand and adjust their thermostats. The two theories are here called the feedback theory and the valve theory. The valve theory is inconsistent with engineering knowledge, but is estimated to be held by 25% to 50% of Americans. Predictions of each of the theories are compared with the operations normally performed in home heat control. This comparison suggests that the valve theory may be highly functional in normal day-to-day use. Further data is needed on the ways this theory guides behavior in natural environments.

What first occurred to me as I began thinking about the origins and development of cinema studies in this country was that I was on some sort of an archeological dig. When I realized that rather than the digger I am one of the ancient objects being unearthed, I abandoned that conceit. Then it occurred to me that perhaps I could see myself as a sailor on the stern of a ship, looking back at its wake. But, as ships move, wakes disappear, from sight and memory. (Also, the noun wake has another meaning that distracted me.) Leaving these poetic flights, I settled in the familiar educational valleys of remembered articles and dissertations, discussions and anecdotes that do remain from years of observing the teaching of film. Personal recollections, then, are the primary source for my ruminations.