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As an intellectual tradition, the history of Hegelianism is the history of the reception and influence of the thought of G.W.F. Hegel. This tradition is notoriously complex and many-sided, because while some Hegelians have seen themselves as merely defending and developing his ideas along what they took to be orthodox lines, others have sought to ‘reform’ his system, or to appropriate individual aspects and overturn others, or to offer consciously revisionary readings of his work. This makes it very hard to identify any body of doctrine common to members of this tradition, and a wide range of divergent philosophical views can be found among those who (despite this) can none the less claim to be Hegelians. There are both ‘internal’ and ‘external’ reasons for this: on one hand, Hegel’s position itself brings together many different tendencies (idealism and objectivism, historicism and absolutism, rationalism and empiricism, Christianity and humanism, classicism and modernism, a liberal view of civil society with an organicist view of the state); any balance between them is hermeneutically very unstable, enabling existing readings to be challenged and old orthodoxies to be overturned. On the other hand, the critical response to Hegel’s thought and the many attempts to undermine it have meant that Hegelians have continually needed to reconstruct his ideas and even to turn Hegel against himself, while each new intellectual development, such as Marxism, pragmatism, phenomenology or existential philosophy, has brought about some reassessment of his position. This feature of the Hegelian tradition has been heightened by the fact that Hegel’s work has had an impact at different times over a long period and in a wide range of countries, so that divergent intellectual, social and historical pressures have influenced its distinct appropriations. At the hermeneutic level, these appropriations have contributed greatly to keeping the philosophical understanding of Hegel alive and open-ended, so that our present-day conception of his thought cannot properly be separated from them. Moreover, because questions of Hegel interpretation have so often revolved around the main philosophical, political and religious issues of the nineteenth and twentieth centuries, Hegelianism has also had a significant impact on the development of modern Western thought in its own right. As a result of its complex evolution, Hegelianism is best understood historically, by showing how the changing representation of Hegel’s ideas have come about, shaped by the different critical concerns, sociopolitical conditions and intellectual movements that dominated his reception in different countries at different times. Initially, Hegel’s influence was naturally most strongly felt in Germany as a comprehensive, integrative philosophy that seemed to do justice to all realms of experience and promised to preserve the Christian heritage in a modern and progressive form within a speculative framework. However, this position was quickly challenged, both from other philosophical standpoints (such as F.W.J. Schelling’s ‘positive philosophy’ and F.A. Trendelenburg’s neo-Aristotelian empiricism), and by the celebrated generation of younger thinkers (the so-called ‘Young’ or ‘Left’ Hegelians, such as Ludwig Feuerbach, David Strauss, Bruno Bauer, Arnold Ruge and the early Karl Marx), who insisted that to discover what made Hegel a truly significant thinker (his dialectical method, his view of alienation, his ‘sublation’ of Christianity), this orthodoxy must be overturned. None the less, both among these radicals and in academic circles, Hegel’s influence was considerably weakened in Germany by the 1860s and 1870s, while by this time developments in Hegelian thought had begun to take place elsewhere. Hegel’s work was known outside Germany from the 1820s onwards, and Hegelian schools developed in northern Europe, Italy, France, Eastern Europe, America and (somewhat later) Britain, each with their own distinctive line of interpretation, but all fairly uncritical in their attempts to assimilate his ideas. However, in each of these countries challenges to the Hegelian position were quick to arise, partly because the influence of Hegel’s German critics soon spread abroad, and partly because of the growing impact of other philosophical positions (such as Neo-Kantianism, materialism and pragmatism). Nevertheless, Hegelianism outside Germany proved more durable in the face of these attacks, as new readings and approaches emerged to counter them, and ways were found to reinterpret Hegel’s work to show that it could accommodate these other positions, once the earlier accounts of Hegel’s metaphysics, political philosophy and philosophy of religion (in particular) were rejected as too crude. This pattern has continued into the twentieth century, as many of the movements that began by defining themselves against Hegel (such as Neo-Kantianism, Marxism, existentialism, pragmatism, post-structuralism and even ‘analytic’ philosophy) have then come to find unexpected common ground, giving a new impetus and depth to Hegelianism as it began to be assimilated within and influenced by these diverse approaches. Such efforts at rapprochement began in the early part of the century with Wilhelm Dilthey’s attempt to link Hegel with his own historicism, and although they were more ambivalent, this connection was reinforced in Italy by Benedetto Croce and Giovanni Gentile. The realignment continued in France in the 1930s, as Jean Wahl brought out the more existentialist themes in Hegel’s thought, followed in the 1940s by Alexander Kojève’s influential Marxist readings. Hegelianism has also had an impact on Western Marxism through the writings of the Hungarian Georg Lukács, and this influence has continued in the critical reinterpretations offered by members of the Frankfurt School, particularly Theodor W. Adorno, Max Horkheimer, Herbert Marcuse, Jürgen Habermas and others. More recently, most of the major schools of philosophical thought (from French post-structuralism to Anglo-American ‘analytic’ philosophy) have emphasized the need to take account of Hegel, and as a result Hegelian thought (both exegetical and constructive) is continually finding new directions.

We generalize the previous study on the application of variational autoencoders to the two-dimensional Ising model to a system with anisotropy. Due to the self-duality property of the system, the critical points can be located exactly for the entire range of anisotropic coupling. This presents an excellent testbed for the validity of using a variational autoencoder to characterize an anisotropic classical model. We reproduce the phase diagram for a wide range of anisotropic couplings and temperatures via a variational autoencoder without the explicit construction of an order parameter. Considering that the partition function of $(d+1)$-dimensional anisotropic models can be mapped to that of the $d$-dimensional quantum spin models, the present study provides numerical evidence that a variational autoencoder can be applied to analyze quantum systems via Quantum Monte Carlo., 11 pages, 5 figures

A bottleneck in efficiently connecting new materials discoveries to established literature has arisen due to an increase in publications. This problem may be addressed by using named entity recognition (NER) to extract structured summary-level data from unstructured materials science text. We compare the performance of four NER models on three materials science datasets. The four models include a bidirectional long short-term memory (BiLSTM) and three transformer models (BERT, SciBERT, and MatBERT) with increasing degrees of domain-specific materials science pre-training. MatBERT improves over the other two BERTBASE-based models by 1%∼12%, implying that domain-specific pre-training provides measurable advantages. Despite relative architectural simplicity, the BiLSTM model consistently outperforms BERT, perhaps due to its domain-specific pre-trained word embeddings. Furthermore, MatBERT and SciBERT models outperform the original BERT model to a greater extent in the small data limit. MatBERT's higher-quality predictions should accelerate the extraction of structured data from materials science literature.

Background Birth by caesarean section (CS) is associated with aberrant gut microbiome development and greater disease susceptibility later in life. We investigated whether oral administration of maternal vaginal microbiota to infants born by CS could restore their gut microbiome development in a pilot single-blinded, randomised placebo-controlled trial (Australian New Zealand Clinical Trials Registry, ACTRN12618000339257). Methods Pregnant women scheduled for a CS underwent comprehensive antenatal pathogen screening. At birth, healthy neonates were randomised to receive a 3 ml solution of either maternal vaginal microbes (CS-seeded, n = 12) or sterile water (CS-placebo, n = 13). Vaginally-born neonates were used as the reference control (VB, n = 22). Clinical assessments occurred within the first 2 h of birth, and at 1 month and 3 months of age. Infant stool samples and maternal vaginal extracts from CS women underwent shotgun metagenomic sequencing. The primary outcome was gut microbiome composition at 1 month of age. Secondary outcomes included maternal strain engraftment, functional potential of the gut microbiome, anthropometry, body composition, and adverse events. Findings Despite the presence of viable microbial cells within transplant solutions, there were no observed differences in gut microbiome composition or functional potential between CS-seeded and CS-placebo infants at 1 month or 3 months of age. Both CS groups displayed the characteristic signature of low Bacteroides abundance, which contributed to a number of biosynthesis pathways being underrepresented when compared with VB microbiomes. Maternal vaginal strain engraftment was rare. Vaginal seeding had no observed effects on anthropometry or body composition. There were no serious adverse events associated with treatment. Interpretation Our pilot findings question the value of vaginal seeding given that oral administration of maternal vaginal microbiota did not alter early gut microbiome development in CS-born infants. The limited colonisation of maternal vaginal strains suggest that other maternal sources, such as the perianal area, may play a larger role in seeding the neonatal gut microbiome. Funding Health Research Council of New Zealand, A Better Start – National Science Challenge.

Applied physics letters 119(19), 194102 (2021). doi:10.1063/5.0063379, A fundamental understanding of superconducting radio frequency Nb cavity processing is necessary to achieve the desired improvement in their performance, which is needed for further upgrades of modern particle accelerators. To recognize the physical processes behind the losses in the accelerator modules, it is required to address not only the observed improvements but also the degradation occurring after different surface treatments. Here, we report on microscopic and spectroscopic studies of several cutouts from an extremely well performing cavity, which showed a systematic degradation after modified surface treatments and annealing conditions. Our results suggest that an abundance of low-angle grain boundaries surrounding the small sized grains can be related to the local superconductivity breakdown at high accelerating field gradients. Losses due to grain boundary segregated carbides are discussed to being most dominant and to leading to an anomalous Q-degradation of the whole cavity starting at low fields., Published by American Inst. of Physics, Melville, NY

By the end of May 2020, all states in the US have eased their COVID-19 mitigation measures. Different states adopted markedly different policies and timing for reopening. An important question remains in how the relaxation of mitigation measures is related to the number of casualties. To address this question, we compare the actual data to a hypothetical case in which the mitigation measures are left intact using a projection of the data from before mitigation measures were eased. We find that different states have shown significant differences in the number of deaths, possibly due to their different policies and reopening schedules. Our study provides a gauge for the effectiveness of the approaches by different state governments and can serve as a guide for implementing best policies in the future. It also indicates that the face mask mandate seems to correlate with the change in the death count more dramatically than other measures., 9 pages, 4 figures, 2 tables

A first series of nitrogen infusion runs of 1.3 GHz single-cell cavities at DESY resulted in an unexpected and severe deterioration observed during the vertical cold test. To investigate the origin of the deterioration, one of the cavities underwent extensive radio-frequency measurements and a temperature- and magnetic field-mapping was performed in collaboration with the Helmholtz-Zentrum Berlin. After combining all results, regions of interests were identified and cut-out of the cavity. Subsequent surface analysis techniques (EBSD, PALS, PIXE, SEM/EDX, SIMS, XPS) were applied in order to identify the microscopic origin of the deterioration and especially the differences between hot and cold spots as well as quench spots. An excess of niobium carbides, reducing the thermal conductivity, was identified as the probable cause for the deterioration, and the size- and density-distributions were observed to be crucial for the resulting performance reduction. The origin for the local differences in the niobium carbide formation between hot and cold spots is an effect of preexisting variations of the crystal structure.

State government-mandated social distancing measures have helped to slow the growth of the COVID-19 pandemic in the United States. Many of the current predictive models of the development of COVID-19, especially after mitigation efforts, partially rely on extrapolations from data collected in other countries. Since most states enacted stay-at-home orders towards the end of March, the resulting effects of social distancing should be reflected in the death and infection counts by the end of April. Using the data available through April 25th, we investigate the change in the infection rate due to the mitigation efforts and project death and infection counts through September 2020 for some of the most heavily impacted states: New York, New Jersey, Michigan, Massachusetts, Illinois, and Louisiana. We find that with the current mitigation efforts, five of those six states have reduced their base reproduction number to a value less than one, stopping the exponential growth of the pandemic. We also project different scenarios after the mitigation is relaxed.

Introduction: There is evidence that caesarean section (CS) is associated with increased risk of childhood obesity, asthma, and coeliac disease. The gut microbiota of CS-born babies differs to those born vaginally, possibly due to reduced exposure to maternal vaginal bacteria during birth. Vaginal seeding is a currently unproven practice intended to reduce such differences, so that the gut microbiota of CS-born babies is similar to that of babies born vaginally. Our pilot study, which uses oral administration as a novel form of vaginal seeding, will assess the degree of maternal strain transfer and overall efficacy of the procedure for establishing normal gut microbiota development. Methods and analysis: Protocol for a single-blinded, randomized, placebo-controlled pilot study of a previously untested method of vaginal seeding (oral administration) in 30 CS-born babies. A sample of maternal vaginal bacteria is obtained prior to CS, and mixed with 5 ml sterile water to obtain a supernatant. Healthy babies are randomized at 1:1 to receive active treatment (3 ml supernatant) or placebo (3 ml sterile water). A reference group of 15 non-randomized vaginal-born babies are also being recruited. Babies’ stool samples will undergo whole metagenomic shotgun sequencing to identify potential differences in community structure between CS babies receiving active treatment compared to those receiving placebo at age 1 month (primary outcome). Secondary outcomes include differences in overall gut community between CS groups (24 hours, 3 months); similarity of CS-seeded and placebo gut profiles to vaginally-born babies (24 hours, 1 and 3 months); degree of maternal vaginal strain transfer in CS-born babies (24 hours, 1 and 3 months); anthropometry (1 and 3 months) and body composition (3 months). Ethics and dissemination: Ethics approval by the Northern A Health and Disability Ethics Committee (18/NTA/49). Results will be published in peer-reviewed journals and presented at international conferences. Registration: Australian New Zealand Clinical Trials Registry (ACTRN12618000339257).

The 2-dimensional Ising model on a square lattice is investigated with a variational autoencoder in the non-vanishing field case for the purpose of extracting the crossover region between the ferromagnetic and paramagnetic phases. The encoded latent variable space is found to provide suitable metrics for tracking the order and disorder in the Ising configurations that extends to the extraction of a crossover region in a way that is consistent with expectations. The extracted results achieve an exceptional prediction for the critical point as well as agreement with previously published results on the configurational magnetizations of the model. The performance of this method provides encouragement for the use of machine learning to extract meaningful structural information from complex physical systems where little a priori data is available.

The contribution begins by considering the reception of German Idealist thought, and principally Kant and Hegel, in the English-speaking world in the second half of the 19th and the first few decades of the 20th century, and the role and character of the translations which facilitated this process. I examine how the early translators conceived of their task and the manner in which they executed it, the particular texts which they chose to translate, and the way they responded to the challenge of introducing an unfamiliar philosophical approach in the context of an established but increasingly contested religious tradition on the one hand and an empirically oriented native philosophical tradition on the other, one which eschewed the use of a systematic and highly elaborated body of conceptual terminology in favour of a literary vernacular. This first wave of translations of German philosophy largely reflected the spectrum of positions represented by the movement subsequently known as British Idealism, and the radical decline in influence of this movement after the Great War led to a marked loss of interest in Hegel, though not to the same degree in Kant, for a considerable period under the dominant influence of analytical philosophy. However, the revival of Hegelian studies over the last fifty years has encouraged a host of fresh translations and retranslations which reflect both new approaches to Hegel and the considerably extended textual base for such work (comprehensive editions including texts once marginalised or ignored, and much previously unpublished material). Likewise the full range of Kant’s mature thought has been increasingly recognised with an enhanced sensitivity to its specific historical and political context. Modern translations have often sought to demystify these authorships and free them from the weight of inherited interpretations, claiming to provide closer textual fidelity and greater terminological precision and consistency in relation to the freer and more tendentious approaches of earlier translators. It is instructive to compare and contrast the styles and specific translation choices here to appreciate the potential losses as well as gains that may arise in some contemporary translation practice (such as the relative neglect of the literary quality and rhetorical features of the source texts in a desire to accommodate them to more standard forms of writing).

As an intellectual tradition, the history of Hegelianism is the history of the reception and influence of the thought of G.W.F. Hegel. This tradition is notoriously complex and many-sided, because while some Hegelians have seen themselves as merely defending and developing his ideas along what they took to be orthodox lines, others have sought to ‘reform’ his system, or to appropriate individual aspects and overturn others, or to offer consciously revisionary readings of his work. This makes it very hard to identify any body of doctrine common to members of this tradition, and a wide range of divergent philosophical views can be found among those who (despite this) can none the less claim to be Hegelians. There are both ‘internal’ and ‘external’ reasons for this: on one hand, Hegel’s position itself brings together many different tendencies (idealism and objectivism, historicism and absolutism, rationalism and empiricism, Christianity and humanism, classicism and modernism, a liberal view of civil society with an organicist view of the state); any balance between them is hermeneutically very unstable, enabling existing readings to be challenged and old orthodoxies to be overturned. On the other hand, the critical response to Hegel’s thought and the many attempts to undermine it have meant that Hegelians have continually needed to reconstruct his ideas and even to turn Hegel against himself, while each new intellectual development, such as Marxism, pragmatism, phenomenology or existential philosophy, has brought about some reassessment of his position. This feature of the Hegelian tradition has been heightened by the fact that Hegel’s work has had an impact at different times over a long period and in a wide range of countries, so that divergent intellectual, social and historical pressures have influenced its distinct appropriations. At the hermeneutic level, these appropriations have contributed greatly to keeping the philosophical understanding of Hegel alive and open-ended, so that our present-day conception of his thought cannot properly be separated from them. Moreover, because questions of Hegel interpretation have so often revolved around the main philosophical, political and religious issues of the nineteenth and twentieth centuries, Hegelianism has also had a significant impact on the development of modern Western thought in its own right. As a result of its complex evolution, Hegelianism is best understood historically, by showing how the changing representation of Hegel’s ideas have come about, shaped by the different critical concerns, sociopolitical conditions and intellectual movements that dominated his reception in different countries at different times. Initially, Hegel’s influence was naturally most strongly felt in Germany as a comprehensive, integrative philosophy that seemed to do justice to all realms of experience and promised to preserve the Christian heritage in a modern and progressive form within a speculative framework. However, this position was quickly challenged, both from other philosophical standpoints (such as F.W.J. Schelling’s ‘positive philosophy’ and F.A. Trendelenburg’s neo-Aristotelian empiricism), and by the celebrated generation of younger thinkers (the so-called ‘Young’ or ‘Left’ Hegelians, such as Ludwig Feuerbach, David Strauss, Bruno Bauer, Arnold Ruge and the early Karl Marx), who insisted that to discover what made Hegel a truly significant thinker (his dialectical method, his view of alienation, his ‘sublation’ of Christianity), this orthodoxy must be overturned. None the less, both among these radicals and in academic circles, Hegel’s influence was considerably weakened in Germany by the 1860s and 1870s, while by this time developments in Hegelian thought had begun to take place elsewhere. Hegel’s work was known outside Germany from the 1820s onwards, and Hegelian schools developed in northern Europe, Italy, France, Eastern Europe, America and (somewhat later) Britain, each with their own distinctive line of interpretation, but all fairly uncritical in their attempts to assimilate his ideas. However, in each of these countries challenges to the Hegelian position were quick to arise, partly because the influence of Hegel’s German critics soon spread abroad, and partly because of the growing impact of other philosophical positions (such as Neo-Kantianism, materialism and pragmatism). Nevertheless, Hegelianism outside Germany proved more durable in the face of these attacks, as new readings and approaches emerged to counter them, and ways were found to reinterpret Hegel’s work to show that it could accommodate these other positions, once the earlier accounts of Hegel’s metaphysics, political philosophy and philosophy of religion (in particular) were rejected as too crude. This pattern has continued into the twentieth century, as many of the movements that began by defining themselves against Hegel (such as Neo-Kantianism, Marxism, existentialism, pragmatism, post-structuralism and even ‘analytic’ philosophy) have then come to find unexpected common ground, giving a new impetus and depth to Hegelianism as it began to be assimilated within and influenced by these diverse approaches. Such efforts at rapprochement began in the early part of the century with Wilhelm Dilthey’s attempt to link Hegel with his own historicism, and although they were more ambivalent, this connection was reinforced in Italy by Benedetto Croce and Giovanni Gentile. The realignment continued in France in the 1930s, as Jean Wahl brought out the more existentialist themes in Hegel’s thought, followed in the 1940s by Alexander Kojève’s influential Marxist readings. Hegelianism has also had an impact on Western Marxism through the writings of the Hungarian Georg Lukács, and this influence has continued in the critical reinterpretations offered by members of the Frankfurt School, particularly Theodor W. Adorno, Max Horkheimer, Herbert Marcuse, Jürgen Habermas and others. More recently, most of the major schools of philosophical thought (from French post-structuralism to Anglo-American ‘analytic’ philosophy) have emphasized the need to take account of Hegel, and as a result Hegelian thought (both exegetical and constructive) is continually finding new directions.

Article Summary An outstanding German poet, Hölderlin is now widely recognized as one of the most important writers and thinkers of his time. After an initial period of critical neglect and relative public indifference, he eventually came to enjoy a privileged status in German cultural life at the beginning of the twentieth century, and has continued to exercise a profound influence on modern literature and critical thought. Hölderlin’s work emerged within the context of Kant’s Critical Revolution and developed in constant interaction with the German Idealist speculation this subsequently provoked, against the background of the French Revolution and the fundamental issues raised in its wake for an entire generation. Hölderlin was personally acquainted with many of the leading figures of the period, including Schiller, Goethe, Herder, Novalis, Fichte, Schelling and Hegel. His writings reflect and respond to many of the central philosophical concerns and themes of his time, in a highly original and prescient fashion. However, it is only since Wilhelm Dilthey that the importance of his specific influence on the intellectual development of Schelling and Hegel in particular has been fully recognized, so that he has even been described as the ‘Doctor Seraphicus’ of German Idealism. His work subsequently provided a frequent point of reference for the Frankfurt School’s engagement with the heritage of German Idealism and the problem of the relationship between aesthetics, ethics and politics. More recently, Hölderlin has become a major presence in much contemporary critical and deconstructive theory, largely through the pervasive influence of Martin Heidegger.

Unsupervised machine learning methods are used to identify structural changes using the melting point transition in classical molecular dynamics simulations as an example application of the approach. Dimensionality reduction and clustering methods are applied to instantaneous radial distributions of atomic configurations from classical molecular dynamics simulations of metallic systems over a large temperature range. Principal component analysis is used to dramatically reduce the dimensionality of the feature space across the samples using an orthogonal linear transformation that preserves the statistical variance of the data under the condition that the new feature space is linearly independent. From there, $k$-means clustering is used to partition the samples into solid and liquid phases through a criterion motivated by the geometry of the reduced feature space of the samples, allowing for an estimation of the melting point transition. This pattern criterion is conceptually similar to how humans interpret the data but with far greater throughput, as the shapes of the radial distributions are different for each phase and easily distinguishable by humans. The transition temperature estimates derived from this machine learning approach produce comparable results to other methods on similarly small system sizes. These results show that machine learning approaches can be applied to structural changes in physical systems.

The ILC Technical Design Report documents the design of a 500 GeV linear collider, but does not specify the centre-of-mass energy steps of operation for the collider. The ILC Parameters Joint Working Group has studied possible running scenarios and the evolution of physics outcomes based on a realistic estimate of the real time accumulation of integrated luminosity, including initial operations ramp-up and upgrades, constrained by a realistic power budget. These physics goals include Higgs precision measurements, top quark measurements and searches for new physics. We present this "optimized" operating scenario and the anticipated evolution of the precision of the ILC measurements.

Physical review accelerators and beams 20(4), 042004(2017). doi:10.1103/PhysRevAccelBeams.20.042004, The successful production and associated vertical testing of over 800 superconducting 1.3 GHz accelerating cavities for the European X-ray Free Electron Laser (XFEL) represents the culmination of over 20 years of superconducting radio-frequency R&D. The cavity production took place at two industrial vendors under the shared responsibility of INFN Milano–LASA and DESY. Average vertical testing rates at DESY exceeded 10 cavities per week, peaking at up to 15 cavities per week. The cavities sent for cryomodule assembly at Commissariat à l’énergie atomique (CEA) Saclay achieved an average maximum gradient of approximately 33 MV/m, reducing to ∼30 MV/m when the operational specifications on quality factor (Q) and field emission were included (the so-called usable gradient). Only 16% of the cavities required an additional surface retreatment to recover their low performance (usable gradient less than 20 MV/m). These cavities were predominantly limited by excessive field emission for which a simple high pressure water rinse (HPR) was sufficient. Approximately 16% of the cavities also received an additional HPR, e.g. due to vacuum problems before or during the tests or other reasons, but these were not directly related to gradient performance. The in-depth statistical analyses presented in this report have revealed several features of the series produced cavities., Published by APS, College Park, MD

This report briefly describes studies performed in the framework of the Collimation Task Force organized to support the work of the second International Linear Collider Technical Review Committee. The post‐linac beam‐collimation systems in the TESLA, JLC/NLC and CLIC linear‐collider designs are compared using the same computer code under the same assumptions. Their performance is quantified in terms of beam‐halo and synchrotron‐radiation collimation efficiency. The performance of the current designs varies across projects, and does not always meet the original design goals. But these comparisons suggest that achieving the required performance in a future linear collider is feasible. Further work of the group is briefly described as well.

In two experiments, we investigate group and individual preferences in a range of different types of patterns with varying fractal-like scaling characteristics. In Experiment 1, we used 1/f filtered grayscale images as well as their thresholded (black and white) and edges only counterparts. Separate groups of observers viewed different types of images varying in slope of their amplitude spectra. Although with each image type, the groups exhibited the “universal” pattern of preference for intermediate amplitude spectrum slopes, we identified 4 distinct sub-groups in each case. Sub-group 1 exhibited a typical peak preference for intermediate amplitude spectrum slopes (“intermediate”; approx. 50%); sub-group 2 exhibited a linear increase in preference with increasing amplitude spectrum slope (“smooth”; approx. 20%), while sub-group 3 exhibited a linear decrease in preference as a function of the amplitude spectrum slope (“sharp”; approx. 20%). Sub-group 4 revealed no significant preference (“other”; approx. 10%). In Experiment 2, we extended the range of different image types and investigated preferences within the same observers. We replicate the results of our first experiment and show that individual participants exhibit stable patterns of preference across a wide range of image types. In both experiments, Q-mode factor analysis identified two principal factors that were able to explain more than 80% of interindividual variations in preference across all types of images, suggesting a highly similar dimensional structure of interindividual variations in preference for fractal-like scaling characteristics.

One of the main challenges in nanoecotoxicological investigations is in the selection of the most suitable measurement methods and protocols for nanoparticle characterisation. Several parameters have been identified as being important as they govern nanotoxicological activity, with some parameters being better defined than others. For example, as a parameter, there is some ambiguity as to how to measure dispersion stability in the context of ecotoxicological investigations; indeed, there is disagreement over which are the best methods to measure nanoparticle dispersion stability. The purpose of this article is to use various commercially available tools to measure dispersion stability and to understand the information given by each tool. In this study, CeO2 was dispersed in two different types of media: de-ionised water and electrolyte-containing fish medium. The DLS mean particle size of freshly dispersed sample in DI water was ~200 nm in diameter. A visual sedimentation experiment showed that nanoparticle dispersion made in the fish medium was less stable compared to corresponding dispersion in de-ionised water. Stability of these dispersions was monitored using various techniques, for a period of 3 days. Our findings have shown that dispersion stability can be suitably assessed by monitoring: (a) surface charge, (b) sedimentation events and (c) presence of agglomerates, through time. The majority of techniques employed here (zeta potential, particle size via DLS, fluorescence and UV–Vis spectroscopy and SEM) were shown to provide useful, complementary information on dispersion stability. Nanoparticle Tracking Analysis (NTA) provides useful, quantitative information on the concentration of nanoparticles in suspension, but is limited by its inability to accurately track the motion of large agglomerates found in the fish medium.