Temporal Regimes Research Articles

1‐kHz hybrid femtosecond/picosecond coherent anti‐Stokes Raman scattering thermometry of turbulent combustion in a representative aeronautical test rig

AbstractThe study of complex reactive flows met in aeronautical engines is an experimental challenge that requires the development of noninvasive and precise measurement techniques. Coherent anti‐Stokes Raman scattering (CARS) is a standard spectroscopic technique used for temperature measurements, which provides unmatched reliability and accuracy at high repetition rate thanks to its recent adaptation to femtosecond temporal regime. This paper reports the first demonstration of hybrid fs/ps‐CARS thermometry in a representative aeronautical combustor (ONERA MICADO test bench, Reynolds number ≈105). Single‐shot N2 CARS spectra have been recorded at 1 kHz, allowing temperature follow up, statistical and frequency (0.1–500 Hz) analysis of CH4/air flame at 0.34‐MPa total pressure. The achieved results demonstrate the ability of the technique to be applied in representative engines conditions and its maturity for semi‐industrial applications.

Introduction

This introduction connects the temporal regimes that disabled people and communities negotiate with the universalization of “crip time” during the COVID-19 pandemic, in full swing at the time of this writing. It discusses the articles and artwork in this special issue in terms of how they express the temporalities lived by disabled subjects both as confining and, potentially, as means of critiquing and transforming the time discipline of late-stage capitalism.

Temporal Regimes in Kenmu nitchū gyōji (Daily Observances of the Kenmu Era), with annotated translation

Abstract This article examines time recording and time practices in Kenmu nitchū gyōji, a medieval document describing daily and monthly routine at the court of Emperor Go-Daigo in the beginning of the fourteenth century. By probing into the text’s chronographic and chronopolitical features, it is shown that Kenmu nitchū gyōji is strongly concerned with temporality, providing an ideal in which court regularities are meant to repeat identically according to a minutely regulated sequential progression. These peculiar temporal characteristics exhibit the text’s political function: by way of a chronological and at the same time cyclical structure, the image of a divine order is provided, thus legitimizing imperial rule.

Impact of noise on development, physiological stress and behavioural patterns in larval zebrafish

Noise pollution is increasingly present in aquatic ecosystems, causing detrimental effects on growth, physiology and behaviour of organisms. However, limited information exists on how this stressor affects animals in early ontogeny, a critical period for development and establishment of phenotypic traits. We tested the effects of chronic noise exposure to increasing levels (130 and 150 dB re 1 μPa, continuous white noise) and different temporal regimes on larval zebrafish (Danio rerio), an important vertebrate model in ecotoxicology. The acoustic treatments did not affect general development or hatching but higher noise levels led to increased mortality. The cardiac rate, yolk sac consumption and cortisol levels increased significantly with increasing noise level at both 3 and 5 dpf (days post fertilization). Variation in noise temporal patterns (different random noise periods to simulate shipping activity) suggested that the time regime is more important than the total duration of noise exposure to down-regulate physiological stress. Moreover, 5 dpf larvae exposed to 150 dB continuous noise displayed increased dark avoidance in anxiety-related dark/light preference test and impaired spontaneous alternation behaviour. We provide first evidence of noise-induced physiological stress and behavioural disturbance in larval zebrafish, showing that both noise amplitude and timing negatively impact key developmental endpoints in early ontogeny.

Dynamical systems approach to evolution-development congruence: Revisiting Haeckel's recapitulation theory.

It is acknowledged that embryonic development has a tendency to proceed from common toward specific. Ernst Haeckel raised the question of why that tendency prevailed through evolution, and the question remains unsolved. Here, we revisit Haeckel's recapitulation theory, that is, the parallelism between evolution and development through numerical evolution and dynamical systems theory. By using intracellular gene expression dynamics with cell‐to‐cell interaction over spatially aligned cells to represent the developmental process, gene regulation networks (GRN) that govern these dynamics evolve under the selection pressure to achieve a prescribed spatial gene expression pattern. For most numerical evolutionary experiments, the evolutionary pattern changes over generations, as well as the developmental pattern changes governed by the evolved GRN exhibit remarkable similarity. Changes in both patterns consisted of several epochs where stripes are formed in a short time, whereas for other temporal regimes, the pattern hardly changes. In evolution, these quasi‐stationary generations are needed to achieve relevant mutations, whereas, in development, they are due to some gene expressions that vary slowly and control the pattern change. These successive epochal changes in development and evolution are represented as common bifurcations in dynamical systems theory, regulating working network structure from feedforward subnetwork to those containing feedback loops. The congruence is the correspondence between successive acquisitions of subnetworks through evolution and changes in working subnetworks in development. Consistency of the theory with the segmentation gene‐expression dynamics is discussed. Novel outlook on recapitulation and heterochrony are provided, testable experimentally by the transcriptome and network analysis.

Melittin exerts opposing effects on short- and long-range dynamics in bicontinuous microemulsions

Bicontinuous microemulsions (BμEs) are a promising biomembrane mimetic system for investigating the behavior of antimicrobial peptides (AMPs) and their delivery to open wounds to combat antibiotic-resistant microorganisms. The properties of the BμE host are in turn affected by the guest AMP and can deviate from those of the unperturbed BμEs, especially at higher AMP concentrations. Here we report the effect of an archetypal AMP, melittin, over a wide range of concentrations, on the nanoscopic dynamics of BμEs formed by water/sodium dodecyl sulfate (SDS)/1-pentanol/dodecane, investigated using quasi-elastic neutron scattering (QENS). Two distinct motions are observed, namely, (i) the lateral motion of the surfactant on the surface of the oil channels and (ii) the internal motion of the surfactants. It is found that melittin restricts both the lateral and the internal motion, thereby acting as a stiffening agent. The lateral motion is more strongly affected, at low concentration of melittin. The lateral diffusion coefficient decreased sharply, approaching a constant value at higher melittin concentration. These results are in sharp contrast with the recent dynamic light scattering and neutron spin echo results which showed that at the length and time scales longer than those probed in the current work, melittin enhanced the long-range collective and local undulation motions of BμEs. Considered together, our results indicate that incorporation of melittin modulates the dynamics differently depending on the spatial and temporal regimes, in which the dynamics are being probed. The addition of melittin at low concentrations increased the magnitude of the zeta potential, but further increase of the melittin concentration decreased it. This suggests that addition of melittin at low concentrations led to increase in the surfactant concentration, but did not affect the negative charge per surfactant molecule, while further addition of melittin led to ion pairing of melittin with the oppositely charged surfactant. This study therefore demonstrates how the addition of melittin hinders the lateral motion of surfactants as a result of the strong association between melittin and SDS, suggesting that the release of AMPs from BμE-based delivery vehicles may be hindered.

Dynamics of long-term protein aggregation on low-fouling surfaces

Understanding the mechanisms of protein interactions with solid surfaces is critical to predict how proteins affect the performance of materials in biological environments. Low-fouling and ultra-low fouling surfaces are often evaluated in short-term protein adsorption experiments, where ‘short-term’ is defined as the time required to reach an initial apparent or pseudo-equilibrium, which is usually less than 600 s. However, it has long been recognized that these short-term observations fail to predict protein adsorption behavior in the long-term, characterized by irreversible accumulation of protein on the surface. This important long-term behavior is frequently ignored or attributed to slow changes in surface chemistry over time—such as oxidation—often with little or no experimental evidence. Here, we report experiments measuring protein adsorption on “low-fouling” and “ultralow-fouling” surfaces using single-molecule localization microscopy to directly probe protein adsorption and desorption. The experiments detect protein adsorption for thousands of seconds, enabling direct observation of both short-term (reversible adsorption) and long-term (irreversible adsorption leading to accumulation) protein-surface interactions. By bridging the gap between these two time scales in a single experiment, this work enables us to develop a single mathematical model that predicts behavior in both temporal regimes. The experimental data in combination with the resulting model provide several important insights: (1) short-term measurements of protein adsorption using ensemble-averaging methods may not be sufficient for designing antifouling materials; (2) all investigated surfaces eventually foul when in long-term contact with protein solutions; (3) fouling can occur through surface-induced oligomerization of proteins which may be a distinct step from irreversible adsorption; and (4) surfaces can be designed to reduce oligomerization or the adsorption of oligomers, to prevent or delay fouling.

Viral Times

Viral Times

The Biographical Method as a Methodological Tradition in Russia: A Review of Projects and Publications

The biographical method in sociology and related disciplines is considered to be firmly rooted in the Western tradition of the first half of the twentieth century (the Chicago School, as well as the Polish memory contests started by F. Znaniecki), while the Russian experience remains largely neglected and unnoticed. The article presents an analytic review of six themes/stages of this movement and their contemporary reception: (1) the N. Rybnikov Institute of Biography, (2) Historical Commissions and Societies, such as Istpart, and others, (3) the Communist Academy, (4) monographic studies and the Central Bureau of Local History, (5) the History of the Civil War and the History of Factories and Plants, Cabinets of Recordings and Memoirs, and (6) the Commission on the History of the Great Patriotic War. All of these initiatives are known to researchers, but so far, they have been studied within the narrow confines of separate disciplines, and almost without regard to the biographical method. A detailed account of these themes in the biographical method context provides us with new optics allowing to reveal the general effects of biographization as the self-reflection of modern society, either with scholarly participation or without it. The review takes into account historical realities and is placed within an interdisciplinary field. The internal continuity is traced in all analyzed projects. Their common features include the articulation of social relevance, the temporal regime, and the organizational specificity of work and its methodological characteristics. The latter are given a detailed account in terms of their relevance to the methodological precepts of contemporary humanities and social sciences.

Experience of Historical Time Perception and Dissatisfaction with the Temporal Regime

Experience of Historical Time Perception and Dissatisfaction with the Temporal Regime

Multiple Times and the Stratigraphies of History

In this article one of the leading theorists of multiple historical time adopts the language of stratigraphy, which Krzysztof Pomian and Reinhart Koselleck used to refer to the layered time of history. It is obvious to the author that “world-time” now exists only as a set of “world-times.” However, unidirectional linear time continues be dominant in the culture, and therefore the main challenge is to come up with unconventional ways of conceptualizing multiple time. During the eighteenth and nineteenth centuries, the “temporalization of history” described by Koselleck took place in the form of “denaturalization” — an opposition between the orders of natural and human life. However, the author concludes that denaturalization today is no longer up to that previous task and calls for treating microbes, planets, rocks and human affairs as having various temporal regimes that permeate each other. The plurality of times is manifested both in practical matters and in branches of knowledge. Fernand Braudel suggested that historians turn to the longue durée of landscapes and climates in order to make history a nomothetic science, but today the task is to analyze the historical and natural worlds, studying their interweaving without reducing them to each other. The author sees the theory of multilayer time as a full-fledged alternative to the idea of linear unidirectional time. Nevertheless, there are phenomena that it cannot describe: how does the quickly streaming surface of everyday life dissolve away, and how do slowly formed events erupt on the surface as natural disasters? In conclusion, the author calls for the incorporation of historiography within a comprehensive theory covering many temporal scales, within which the historical life of people is intertwined with the historical life of rocks and geological deposits.

Clustering Commodity Markets in Space and Time: Clarifying Returns, Volatility, and Trading Regimes Through Unsupervised Machine Learning

Unsupervised machine learning can interpret logarithmic returns and conditional volatility in commodity markets. k-means and hierarchical clustering can generate a financial ontology of markets for fuels, precious and base metals, and agricultural commodities. Manifold learning methods such as multidimensional scaling (MDS) and t-distributed stochastic neighbor embedding (t-SNE) enable the visualization of comovement and other financial relationships in three dimensions.Different methods of unsupervised learning excel at different tasks. k-means clustering based on logarithmic returns works well with MDS to classify commodities and to create a spatial ontology of commodities trading, A strikingly different application involves k-means clustering of the matrix transpose, such that conditional volatility is evaluated by trading date rather than by commodity. This approach can isolate the two most calamitous temporal regimes of the past two decades: the global financial crisis of 2008-09 and the immediate reaction to the Covid-19 pandemic. Temporal clustering of trading days, unlike the corresponding spatial task of clustering commodities, is better visualized through t-SNE than through MDS.

“New Wars”: Disappearance of the Future and/or Synchronization of Temporalities

The future-oriented temporal regime of modernity is today being replaced by presentism in the perception of time, not only in Russia or Eastern Europe, but throughout the world. However, this presentism does not always imply subordination of the past and future to the interests of the present. It may involve a conflict among temporalities, which will be settled by a violent synchronization of heterogeneous temporal outlooks or by recognizing radical time gaps. Most often, the politics of time is observable at the macro-level — as subordination of common commemoration practices to dominant narratives or regimes that exercise power over knowledge. In this interpretation, “politics from below” acts as a response to hegemony, but its failure is inevitable. The article points out the artificiality of that dichotomy by studying the writings about “new wars,” which are now becoming a decentralized system for the use of violence to reach extremely varied pragmatic goals. One of those goals is managing the future in a “risk society” or the endless prolongation of a present in which the boundary between ordinary and extraordinary violence is blurred. But at the same time, the “new wars” are also synchronizing “from below.” The politics of time is generated by the incompatibilities between past, present and future without ever reaching a stable symbolic hierarchy. Under these conditions it becomes quite difficult to separate “wartime” and “peacetime”. The article takes up the problematic nature of this demarcation in relation to cotemporary local conflicts in both Russia and the West.

The Concept of Time in Soviet Neoclassicism (On the Example of Architectural Discourse)

The article discusses the process of switching temporal regimes in Soviet culture at the turn of the 1920s - and during the 1930s on the material of architecture. The concepts of time in constructivism and neoclassicism are compared since the struggle between them determined the main vectors of artistic development in the reconstruction period. The author analyzes the discourse of the official position in relation to the main trends in the development of architecture in the context of the periodization of socialist construction and elicits the reasons for supporting the reference to the classical heritage. The change of political agenda (the transition from dismantling the old order and the rectification of the consequences of the collapse of the social fabric as a way to build a new social order) set new requirements for architecture as the most important way of social representation. The new society - socialism - was interpreted in constructivism, which was the leading direction of 1920s architecture, in the modus of the future. In the neoclassicism of the 1930s, socialism was placed in the modus of the present. Constructivism was aimed at the pragmatics of restoring social fabric and solving current problems (mass housing, a new social infrastructure), as well as at constructing a future society and human. At the end of the first five-year plan, the authorities set other goals for culture in general and architecture in particular: the representation of achievements and the expression of the greatness of socialist construction. Neoclassicism was called upon to perpetuate the present state of affairs in the modus of real perfection and superiority of Soviet socialism over any other formats of social life. Between the time of creation (constructivism) and the time of completion (neoclassicism), there is formed a gap that must be hidden. As a way of hiding the temporal gap were chosen classical principles of form-making and examples of the Renaissance and Russian classicism, that were designed to convincingly demonstrate, on the one hand, the possibility of accelerating and compressing time, the swiftness of achieving the ideal, and on the other hand, tp depreciate innovations, make the idea of the movement of time into the future unnecessary. The theory of the leading neoclassicist I. Zholtovsky is discussed as an alternative to the utopian interpretation of time in constructivism, as materializing the mythological time, in which the source and end of creation are given simultaneously in the modus of eternity.

Quantum Brownian motion: Drude and Ohmic baths as continuum limits of the Rubin model.

The motion of a free quantum particle in a thermal environment is usually described by the quantum Langevin equation, where the effect of the bath is encoded through a dissipative and a noise term, related to each other via the fluctuation dissipation theorem. The quantum Langevin equation can be derived starting from a microscopic model of the thermal bath as an infinite collection of harmonic oscillators prepared in an initial equilibrium state. The spectral properties of the bath oscillators and their coupling to the particle determine the specific form of the dissipation and noise. Here we investigate in detail the well-known Rubin bath model, which consists of a one-dimensional harmonic chain with the boundary bath particle coupled to the Brownian particle. We show how in the limit of infinite bath bandwidth, we get the Drude model, and a second limit of infinite system-bath coupling gives the Ohmic model. A detailed analysis of relevant equilibrium correlation functions, such as the mean squared displacement, velocity autocorrelation functions, and response function are presented, with the aim of understanding the various temporal regimes. In particular, we discuss the quantum-to-classical crossover time scales where the mean square displacement changes from a ∼lnt to a ∼t dependence. We relate our study to recent work using linear response theory to understand quantum Brownian motion.

Dream Time, Modality, and Counterfactual Imagination in Thomas Pynchon’s Mason & Dixon

This paper elucidates the structure and scope of Pynchon’s temporal imagination by studying the complex relations between narrative time and modality in his 1997 novel Mason & Dixon using the conceptual framework of contemporary narratology. It argues that Pynchon’s use of the subjunctive mode allows him not only to articulate the political and ideological concerns in his vision of America on the eve of its founding but also to address the problems of historicity, causality and irreversibility of time. By employing the subjunctive as a general narrative strategy, Mason & Dixon challenges the various temporal regimes and discourses of modernity, and projects imaginative re-figurations of time and space. In carrying this out, the novel moves beyond what Pynchon calls “the network of ordinary latitude and longitude” (Against the Day 250) and replaces a totalizing singularity with plurality of times and timescapes

Predicting the Impact of Poor Thermal Management on Aging within Strings of Li-Ion Cells

Large-format batteries comprised of hundreds if not thousands of cells are becoming more common as battery energy storage moves to greater applications in automotive, grid and industrial scenarios. Such battery packs require thermal management (TM) to mitigate the accumulation of heat generated during routine and above-routine use. Thus, to preserve cell-to-battery life and performance, good TM should quickly account for variable thermal loads over diverse timescales and minimize cell-to-cell temperature variance referred to as “hot spots”. The need to streamline battery packs to minimal configurations (that can cause geometric bottlenecks for TM) and to reduce their cost will no doubt lead to persistence of hot spots for many applications. Hot spots will cause local cells to age faster than cells outside the hot spot region, with consequences toward decreased energy capacity, higher electrical and thermal impedance, and reduced power. Such disparate cell aging is problematic for large-format batteries in terms of management of cell replacements and ultimate profitability of the energy storage installation. This work is based on battery aging simulations done with INL CellSage, a physics-based software tool that considers cell and series string aging characteristics dependent on prevalent stress factors over time (Gering (2017)).We seek to understand how batteries will age in their intended applications, and whether the battery will perform through its warranty period. Central to this is Aging Path Dependence, which asserts the sequence of aging conditions over time has a direct influence on irreversible aging trends of battery systems. Physics-based tools like CellSage can help guide these issues. Typical input parameters within CellSage include cell chemistry, SOC, T and DT during duty cycle, location of use (US cities), duty cycle and frequency thereof, TM metrics, string attributes, and others. Duty cycles can be customized for particular applications and up to 25 cells are considered per series string, but that can be increased.First, Fig. 1 shows how a 10 ⁰C hot spot in the center of a 7-cell series string can affect capacity loss within local Li-ion cells. The cell chemistry is Gr/NCA, and the duty cycle is defined by scaled HEV power cycling at 80% SOC. The location of operation is Phoenix, Arizona and the maximum temperature permitted under TM is 30 ⁰C, so the hot spot is at 40 ⁰C at its center. The effects of daily thermal cycling were included as a stress factor. At the end of 200 weeks the center cell has undergone nearly 15% more capacity loss than cells located at the edges of the hot spot. Increased impedance at the hot spot (not shown) together with capacity loss will render a significant impact in power delivery for this string.Fig. 2 shows results for simulating power loss in an 11-cell series string comprised of LFP 26650-type cells operating in Phoenix. No battery TM is imposed, and a 10 ⁰C hot spot (symmetrical) is assumed. Two cases of operation are considered: (1) shallow power pulses for SOC near constant around 90% SOC (solid curves), and (2) deeper power pulses that cover 90 to 30% SOC (dashed curves). The stair-step profiles in the string power curves are due to the annual temperature cycle in Phoenix. While the hot spot accelerates the loss of string power, the case of deeper power pulses over a larger SOC range has a greater influence on the aging rate. Optimization of string life can be done through simultaneous consideration of SOC and TM parameters and total cells in the string, as a start.Lastly, Fig. 3 shows the outcome for string power simulations for the same LFP cell and string basis as for Fig. 2, but including TM and considering different geographic locations in the US. Here the upper temperature limit for TM is 30 ⁰C while the lower limit is set at 10 ⁰C. Under this TM condition the aging of the strings is more consistent, with some cities producing very similar trends such as Phoenix, Miami and Honolulu.To conclude, large-format batteries carry with them a need for TM that will be consistent within spatial, temporal and power regimes. The longevity and cell replacement costs of such batteries are directly related to TM effectiveness. If string aging is understood ahead of time, large-format battery design would benefit by having a proper balance between cells onboard and the cell replacement schedule. While simple cases are given in this abstract, more complicated scenarios will be presented for larger systems and more complex duty cycles.

Round-robin measurements of the laser-induced damage threshold with sub-picosecond pulses on optical single layers

The standardization and comparison of laser-damage protocols and results are essential prerequisites for development and quality control of large optical components used in high-power laser facilities. To this end, the laser-induced–damage thresholds of two different coatings were measured in a round-robin experiment involving five well-equipped damage testing facilities. Investigations were conducted at the wavelength of 1 μm in the sub picosecond pulse duration range with different configurations in terms of polarization, angle of incidence, and environment (air versus vacuum). In this temporal regime, the damage threshold is known to be deterministic, i.e., the continuous probability distribution transitions from 0 to 1 over a very narrow fluence range. This in turn implies that the damage threshold can be measured very precisely. These characteristics enable direct comparison of damage-threshold measurements between different facilities, with the difference in the measured values indicating systematic errors or other parameters that were not previously appreciated. The results of this work illustrate the challenges associated with accurately determining the damage threshold in the short-pulse regime. Specifically, the results of this round-robin damage-testing effort exhibited significant differences between facilities. The factors to be taken into account when comparing the results obtained with different test facilities are discussed: temporal and spatial profiles, environment, damage detection, sample homogeneity, and nonlinear beam propagation.

The temporal regimes of HIV/AIDS activism in Europe: chrono-citizenship, biomedicine and its others

ABSTRACT HIV/AIDS is known to have fundamentally transformed fields of biomedical research, the governance of health, and state–citizen relations. Based on research that was developed to analyze these transformations within HIV/AIDS activism at the European-level, we offer the term chrono-citizenship to describe the influence of time in constructs of citizenship. We argue that the temporal regime of biomedicine, or modes of governance that depend on biomedical understandings of time, have come to dominate HIV/AIDS narratives, policies and programs. Building on oral histories and three years of fieldwork in spaces of European-level networks and health-governing bodies, we suggest that citizenship in the field of HIV/AIDS has been defined through multiple, intersecting and, at times, antagonistic temporal regimes. To illustrate this, we expose the regime of loss, through which mourning, often denied space in the present, bears potential for new forms of subjectivity and community; the regime of sustainability, which centers the planning and surveillance of budgets over service provision in a climate unfriendly to human rights; and the regime of chronic crisis, in which persistence becomes a form of political agency against ongoing exclusion and disappointment. As we show, unearthing varied temporalities helps to denaturalize biomedical understandings of time, and invites a rethinking of the foundations needed to reach the ‘end of AIDS’ sought by civil society, UNAIDS and other health-governing bodies.

Quantitative comparison between sub-millisecond time resolution single-molecule FRET measurements and 10-second molecular simulations of a biosensor protein.

Molecular Dynamics (MD) simulations seek to provide atomic-level insights into conformationally dynamic biological systems at experimentally relevant time resolutions, such as those afforded by single-molecule fluorescence measurements. However, limitations in the time scales of MD simulations and the time resolution of single-molecule measurements have challenged efforts to obtain overlapping temporal regimes required for close quantitative comparisons. Achieving such overlap has the potential to provide novel theories, hypotheses, and interpretations that can inform idealized experimental designs that maximize the detection of the desired reaction coordinate. Here, we report MD simulations at time scales overlapping with in vitro single-molecule Förster (fluorescence) resonance energy transfer (smFRET) measurements of the amino acid binding protein LIV-BPSS at sub-millisecond resolution. Computationally efficient all-atom structure-based simulations, calibrated against explicit solvent simulations, were employed for sampling multiple cycles of LIV-BPSS clamshell-like conformational changes on the time scale of seconds, examining the relationship between these events and those observed by smFRET. The MD simulations agree with the smFRET measurements and provide valuable information on local dynamics of fluorophores at their sites of attachment on LIV-BPSS and the correlations between fluorophore motions and large-scale conformational changes between LIV-BPSS domains. We further utilize the MD simulations to inform the interpretation of smFRET data, including Förster radius (R0) and fluorophore orientation factor (κ2) determinations. The approach we describe can be readily extended to distinct biochemical systems, allowing for the interpretation of any FRET system conjugated to protein or ribonucleoprotein complexes, including those with more conformational processes, as well as those implementing multi-color smFRET.