Unified Perspective Research Articles

One-component quantum mechanics and dynamical leakage-free paths

We derive an exact one-component equation of motion for the probability amplitude of a target time-dependent state, and use the equation to reformulate quantum dynamics and control for both closed and open systems. Using the one-component equation, we show that an unexpected time-dependent leakage-free path can be induced and we capture a necessary quantity in determining the effect of decoherence suppression. Our control protocol based on the nonperturbative leakage elimination operator provides a unified perspective connecting some subtle, popular, and important concepts of quantum control, such as dynamical decoupling, quantum Zeno effect, and adiabatic passage. The resultant one-component equation will promise significant advantages in both quantum dynamics and control.

Quantum technologies: a course for teacher professional development.

We present an educational path for teacher professional development whose primary purpose is to enhance physics teachers’ knowledge and awareness of topics related to quantum computation and quantum information, and of their relevance for technological advancement. Besides their objective importance, also stressed by several authors and projects, the choice of topics not traditionally covered in the final year physics curricula also arises from the concrete possibility of developing a multidisciplinary path, able to represent under a unified perspective several subjects treated in secondary school physics and mathematics. The project is realized in the context of the Italian PLS (Plan for Science Degrees) and the education section of the Quantum Flagship. Due to the limitations related to the COVID-19 pandemic it was entirely delivered in the form of synchronous distance learning and was attended by around 30 teachers. Asynchronous discussion was performed using both generally available tools (Google drive, forms etc.) and a dedicated online forum set up on the servers of the University of Pavia. We discuss the structure of the educational path and the results of the first part of the course whose purpose was describing the transition from classical to quantum computation. In general, from both the written pre-questionnaire and the mid-course interviews, strong appreciation and fascination emerge for the cultural significance of the introduced topics and connections.

A Mathematical Framework for Learning Probability Distributions

The modeling of probability distributions, specifically generative modeling and density estimation, has become an immensely popular subject in recent years by virtue of its outstanding performance on sophisticated data such as images and texts. Nevertheless, a theoretical understanding of its success is still incomplete. One mystery is the paradox between memorization and generalization: In theory, the model is trained to be exactly the same as the empirical distribution of the finite samples, whereas in practice, the trained model can generate new samples or estimate the likelihood of unseen samples. Likewise, the overwhelming diversity of distribution learning models calls for a unified perspective on this subject. This paper provides a mathematical framework such that all the well-known models can be derived based on simple principles. To demonstrate its efficacy, we present a survey of our results on the approximation error, training error and generalization error of these models, which can all be established based on this framework. In particular, the aforementioned paradox is resolved by proving that these models enjoy implicit regularization during training, so that the generalization error at early-stopping avoids the curse of dimensionality. Furthermore, we provide some new results on landscape analysis and the mode collapse phenomenon.

Domestic Settler Writing and the Global Nineteenth Century

Domestic settler writing has long remained a largely overlooked by-product of imperial expansion and the resultant exportation of popular culture. Global nineteenth-century studies may offer an opportunity to reconsider this admittedly amorphous set of writing from a newly unifying perspective. Approaching these texts through different lenses does more than bring them to renewed scholarly attention and tease out hitherto unacknowledged aspects. In turn, they can enrich global nineteenth-century studies itself, ensuring that the experience of female settlers, emigrating families, and unaccompanied children are not once again marginalized. This article resituates domestic settler writing within a transoceanic, global field of representations, setting out three specific directions for the critical investigation to proceed: (1) a distant reading to capture patterns, (2) a mapping of the circulation of such colonial reading matter, and (3) a comparative analysis, especially of texts that engage with such exchanges, through intertextual references or rewritings.

A Unifying Perspective on Perception and Cognition Through Linguistic Representations of Emotion.

This article will provide a unifying perspective on perception and cognition via the route of linguistic representations of emotion. Linguistic representations of emotions provide a fertile ground for explorations into the nature and form of integration of perception and cognition because emotion has facets of both perceptual and cognitive processes. In particular, this article shows that certain types of linguistic representations of emotion allow for the integration of perception and cognition through a series of steps and operations in cognitive systems, whereas certain other linguistic representations of emotion are not so representationally structured as to permit the unity of perception and cognition. It turns out that the types of linguistic representations of emotion that readily permit the desired unity of perception and cognition are exactly those that are linguistically encoded emotive representations of everyday objects, events, and things around us. It is these ordinary objects, events and things that provide the scaffolding for task-dependent or goal-oriented activities of cognitive systems including autonomous systems. In this way, cognitive systems can be saliently tuned to the outer world by being motivated and also subtly governed by emotion-driven representations. This helps not only tie together perceptual and cognitive processes via the interface between language and emotive representations, but also reveal the limits of emotive representations in amalgamating perceptual and cognitive processes in cognitive systems.

A semi-analytical benchmark for the Stefan problem in arbitrary dimension – assessing accuracy of enthalpy-based methods

PurposeThis paper aims to propose a semi-analytical benchmarking framework for enthalpy-based methods used in problems involving phase change with latent heat. The benchmark is based on a class of semi-analytical solutions of spatially symmetric Stefan problems in an arbitrary spatial dimension. Via a public repository this study provides a finite element numerical code based on the FEniCS computational platform, which can be used to test and compare any method of choice with the (semi-)analytical solutions. As a particular demonstration, this paper uses the benchmark to test several standard temperature-based implementations of the enthalpy method and assesses their accuracy and stability with respect to the discretization parameters.Design/methodology/approachThe class of spatially symmetric semi-analytical self-similar solutions to the Stefan problem is found for an arbitrary spatial dimension, connecting some of the known results in a unified manner, while providing the solutions’ existence and uniqueness. For two chosen standard semi-implicit temperature-based enthalpy methods, the numerical error assessment of the implementations is carried out in the finite element formulation of the problem. This paper compares the numerical approximations to the semi-analytical solutions and analyzes the influence of discretization parameters, as well as their interdependence. This study also compares accuracy of these methods with other traditional approach based on time-explicit treatment of the effective heat capacity with and without iterative correction.FindingsThis study shows that the quantitative comparison between the semi-analytical and numerical solutions of the symmetric Stefan problems can serve as a robust tool for identifying the optimal values of discretization parameters, both in terms of accuracy and stability. Moreover, this study concludes that, from the performance point of view, both of the semi-implicit implementations studied are equivalent, for optimal choice of discretization parameters, they outperform the effective heat capacity method with iterative correction in terms of accuracy, but, by contrast, they lose stability for subcritical thickness of the mushy region.Practical implicationsThe proposed benchmark provides a versatile, accessible test bed for computational methods approximating multidimensional phase change problems. The supplemented numerical code can be directly used to test any method of choice against the semi-analytical solutions.Originality/valueWhile the solutions of the symmetric Stefan problems for individual spatial dimensions can be found scattered across the literature, the unifying perspective on their derivation presented here has, to the best of the authors’ knowledge, been missing. The unified formulation in a general dimension can be used for the systematic construction of well-posed, reliable and genuinely multidimensional benchmark experiments.

Building a Culture of Biosafety, Biosecurity, and Responsible Conduct in the Life Sciences: A View from Mali

Adherence to biosafety and biosecurity standards and practices by those involved in the life sciences is essential to protecting the health of humans, animals, and the environment. Fostering a culture of responsibility is one of the underlying tenets of the Biological Weapons Convention, the Global Health Security Agenda, Joint External Evaluation of International Health Regulations, and the Global Partnership Against the Spread of Weapons and Materials of Mass Destruction. It also underpins national and international efforts to protect science from misuse and to protect workers and the public from laboratory incidents. Unlike the nuclear domain, there is no available guidance or unified perspective on the nature of this culture or how it may be assessed. The International Working Group on Strengthening the Culture of Biosafety, Biosecurity, and Responsible Conduct in the Life Sciences developed a framework to assess organizational culture in biological laboratories based on the model developed by the International Atomic Energy Agency for nuclear facilities. This framework encompasses 1) management systems; 2) behavior of leadership and personnel; 3) principles for guiding decisions and behaviors; and 4) beliefs, opinions and attitudes. Here we present an example of how the beliefs, opinions, and attitudes element was employed to assess the organizational culture of laboratorians from five regions in Mali. This is the first assessment using the framework and, as such, provides a model for others seeking to improve biosafety and biosecurity, and may ultimately lead to international harmonization of this concept and provide a pathway to strengthen Mali’s laboratory system.

Https://tmstudies.net/index.php/ectms/issue/view/75

Despite the growing interest in consumption experience, literature claims for a unifying perspective, combining elements from consumers and marketers, depicting the complexity of this phenomenon. This article addresses this research gap and aims to develop a literature review on consumption experience, drawing its social and intellectual structure, and set a research agenda. In a hybrid literature review composed of bibliometric analysis and a systematic review, we examined 90 papers from high-quality journals on business and management areas. Findings indicate six research interests: escape experiences, virtual experiences, customer journey, customer experience innovation, service experience, and customer experience management. This analysis led us to draw a research agenda composed of the main gaps in consumption experience, engendering the main contribution of this paper. The future of this literature must consider developments in escape experiences, online customer experience, service experience, customer experience management, and the intersection between these themes.

Efficiency at optimal performance: A unified perspective based on coupled autonomous thermal machines.

We show that coupled autonomous thermal machines, in the presence of three heat reservoirs and following a global linear-irreversible description, can have efficiency at maximum power (EMP) which is analogous in form to the EMP of models with two (hot and cold) reservoirs. In particular, the temperature dependence of EMP in the coupled model is via only the ratio of hot and cold temperatures if the intermediate reservoir temperature is expressed as an algebraic mean of these temperatures. Many popular expressions of EMP in the literature can be recovered by making a choice of some standard mean. Further, the universal properties of EMP near equilibrium can be explained in terms of the properties of symmetric means. For the case of broken time-reversal symmetry, a universal second-order coefficient of 6/49 is predicted in the series expansion of EMP, analogous to the 1/8 coefficient in the time-reversal symmetric case.

Unifying Perspective of the Ultrafast Photodynamics of Orange Carotenoid Proteins from Synechocystis: Peril of High-Power Excitation, Existence of Different S* States, and Influence of Tagging.

A substantial number of Orange Carotenoid Protein (OCP) studies have aimed to describe the evolution of singlet excited states leading to the formation of a photoactivated form, OCPR. The most recent one suggests that 3 ps-lived excited states are formed after the sub-100 fs decay of the initial S2 state. The S* state, which has the longest reported lifetime of a few to tens of picoseconds, is considered to be the precursor of the first red photoproduct P1. Here, we report the ultrafast photodynamics of the OCP from Synechocystis PCC 6803 carried out using visible–near infrared femtosecond time-resolved absorption spectroscopy as a function of the excitation pulse power and wavelength. We found that a carotenoid radical cation can form even at relatively low excitation power, obscuring the determination of photoactivation yields for P1. Moreover, the comparison of green (540 nm) and blue (470 nm) excitations revealed the existence of an hitherto uncharacterized excited state, denoted as S∼, living a few tens of picoseconds and formed only upon 470 nm excitation. Because neither the P1 quantum yield nor the photoactivation speed over hundreds of seconds vary under green and blue continuous irradiation, this S∼ species is unlikely to be involved in the photoactivation mechanism leading to OCPR. We also addressed the effect of His-tagging at the N- or C-termini on the excited-state photophysical properties. Differences in spectral signatures and lifetimes of the different excited states were observed at a variance with the usual assumption that His-tagging hardly influences protein dynamics and function. Altogether our results advocate for the careful consideration of the excitation power and His-tag position when comparing the photoactivation of different OCP variants and beg to revisit the notion that S* is the precursor of photoactivated OCPR.

Research on Line Planning and Timetabling Optimization Model Based on Passenger Flow of Subway Network

In this paper, we propose a line planning and timetabling optimization model considering operation cost and passenger satisfaction based on passenger flow. By comprehensively considering the operation cost and passenger waiting cost, the comprehensive social benefits of the line network operation organization are evaluated from a unified perspective. The passenger flow model based on queuing theory is adopted, which can better describe the relationship between passenger flow change and passenger waiting time. The integrated optimization model of the line network is constructed, and mixed integer quadratic programming is adopted, which has the advantages of accurate results and fast convergence. Through the simulation case analysis, the correctness of the method proposed in this paper is verified.

Landscape-Based Protein Stability Analysis and Network Modeling of Multiple Conformational States of the SARS-CoV-2 Spike D614G Mutant: Conformational Plasticity and Frustration-Induced Allostery as Energetic Drivers of Highly Transmissible Spike Variants.

The structural and functional studies of the SARS-CoV-2 spike protein variants revealed an important role of the D614G mutation that is shared across many variants of concern (VOCs), suggesting the effect of this mutation on the enhanced virus infectivity and transmissibility. The recent structural and biophysical studies provided important evidence about multiple conformational substates of the D614G spike protein. The development of a plausible mechanistic model that can explain the experimental observations from a more unified thermodynamic perspective is an important objective of the current work. In this study, we employed efficient and accurate coarse-grained simulations of multiple structural substates of the D614G spike trimers together with the ensemble-based mutational frustration analysis to characterize the dynamics signatures of the conformational landscapes. By combining the local frustration profiling of the conformational states with residue-based mutational scanning of protein stability and network analysis of allosteric interactions and communications, we determine the patterns of mutational sensitivity in the functional regions and sites of variants. We found that the D614G mutation may induce a considerable conformational adaptability of the open states in the SARS-CoV-2 spike protein without compromising the folding stability and integrity of the spike protein. The results suggest that the D614G mutant may employ a hinge-shift mechanism in which the dynamic couplings between the site of mutation and the interprotomer hinge modulate the interdomain interactions, global mobility change, and the increased stability of the open form. This study proposes that mutation-induced modulation of the conformational flexibility and energetic frustration at the interprotomer interfaces may serve as an efficient mechanism for allosteric regulation of the SARS-CoV-2 spike proteins.

Wearable Wrist Photoplethysmography for Optimal Monitoring of Vital Signs: A Unified Perspective on Pulse Waveforms

To track vital signs on the wrist, a wearable system, named WrisTee, has been developed for remote health monitoring. Using three optical sensors with four light sources, WrisTee allows users to measure 12 photoplethysmogram (PPG) signals at three locations on the radial artery. Two types of PPG signals with opposite polarities were discovered and designated as in-phase and invert-phase signals. We provided a unified viewpoint regarding their differences based on the Beer <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$-$</tex-math></inline-formula> Lambert law, and showed that both signals can be used for heart monitoring using data analyzed from a selected subject. Using reflective pulse-transition time (R-PTT) and the standard deviation of R-PTT ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sigma _{R\text{-}PTT}$</tex-math></inline-formula> ), we proposed a method for selecting the optimal wavelength to achieve the best quality signal, thus minimizing storage requirements, power resources, and computational costs. We conducted an experiment on ten subjects to evaluate the feasibility of the proposed method. Our results demonstrated that WrisTee is capable of finding the optimal positions and wavelengths for monitoring vital signs. To automatically detect the PPG phases, six machine learning (ML) models were explored to assess their accuracy for PPG-phase classification. The experimental results show that a convolutional neural network can be the best candidate for phase classification. Hence, it can be integrated into WrisTee for noninvasive health monitoring such as heart rate, heart rate variability, or blood pressure. Our work paves a new direction in bio-signal medical researches by adopting in-phase and invert-phase PPGs for healthcare monitoring.

Iterative algorithm for discrete structure recovery

We propose a general modeling and algorithmic framework for discrete structure recovery that can be applied to a wide range of problems. Under this framework, we are able to study the recovery of clustering labels, ranks of players, signs of regression coefficients, cyclic shifts and even group elements from a unified perspective. A simple iterative algorithm is proposed for discrete structure recovery, which generalizes methods including Lloyd’s algorithm and the power method. A linear convergence result for the proposed algorithm is established in this paper under appropriate abstract conditions on stochastic errors and initialization. We illustrate our general theory by applying it on several representative problems: (1) clustering in Gaussian mixture model, (2) approximate ranking, (3) sign recovery in compressed sensing, (4) multireference alignment and (5) group synchronization, and show that minimax rate is achieved in each case.

Awareness is in the eye of the observer: Preserved third-person awareness of deficit in anosognosia for hemiplegia

In recent decades, the research traditions of (first-person) embodied cognition and of (third-person) social cognition have approached the study of self-awareness with relative independence. However, neurological disorders of self-awareness offer a unifying perspective to empirically investigate the contribution of embodiment and social cognition to self-awareness. This study focused on a neuropsychological disorder of bodily self-awareness following right-hemisphere damage, namely anosognosia for hemiplegia (AHP). A previous neuropsychological study has shown AHP patients, relative to neurological controls, to have a specific deficit in third-person perspective taking and allocentric stance (the other unrelated to the self) in higher order mentalizing tasks. However, no study has tested if verbal awareness of motor deficits is influenced by perspective-taking and centrism and identified the related anatomical correlates. Accordingly, two novel experiments were conducted with right-hemisphere stroke patients with (n = 17) and without AHP (n = 17) that targeted either their own (egocentric, experiment 1) or another stooge patients (allocentric, experiment 2) motor abilities from a first-or-third person perspective. In both experiments, neurological controls showed no significant difference in perspective-taking, suggesting that social cognition is not a necessary consequence of right-hemisphere damage. More specifically, experiment 1 found AHP patients more aware of their own motor paralysis (egocentric stance) when asked from a third compared to a first-person perspective, using both group level and individual level analysis. In experiment 2, AHP patients were less accurate than controls in making allocentric judgements about the stooge patient, but with only a trend towards significance and with no difference between perspectives. As predicted, deficits in egocentric and allocentric third-person perspective taking were associated with lesions in the middle frontal gyrus, superior temporal and supramarginal gyri, and white matter disconnections were more prominent with deficits in allocentricity. Behavioural and neuroimaging results demonstrate the intersecting relationship between bodily self-awareness and self-and-other-directed metacognition or mentalisation.

An interactive dashboard to track themes, development maturity, and global equity in clinical artificial intelligence research

An interactive dashboard to track themes, development maturity, and global equity in clinical artificial intelligence research

How to measure and monitor the transportation infrastructure contribution to logistics value of supply chains?

When it comes to the competitiveness of companies, and of nations, the key role of the transportation infrastructure to increase logistics value of supply chains is clearly acknowledged. For example, the lack and/or inadequate transportation infrastructure is often mentioned as the most important challenge to companies located in emerging countries to successfully participate in global supply chains. In fact, many comparative indicators that measure countries’ competitiveness consider infrastructure of transportation as a key element. Nonetheless, most part of them give more credit either to the infrastructure density (km of roads per km2 of territory) or to the amount of resources invested in its development (millions of dollars) than to the its logistics effectiveness and resilience that may bring to the supply chain operations. Based on six indicators: i) Travel time (95 PCTL); ii) Average travel time; iii) Projected travel time; iv) Freight rates; v) Risk of accident; and vi) Carbon footprint, the objective of this paper is twofold. First, to propose a standardized measurement approach of logistics value provided by the transportation infrastructure to supply chains as a unified perspective. Second, to expose a proof of concept of an interactive digital map that is useful for public and private sectors when making decisions. The results obtained are useful for academics as well as for public and private decision makers. It delivers insights about the potential of data when looking to increase logistics performance of companies and regions. Finally, a proposal for future research is presented.

Analysis of MP4 Videos in 5G Using SDN

Current video content providers require a huge demand for network resources to obtain the best quality of experience from the end-users perspective. This measure can be achieved if the network can anticipate itself to different existing issues (bandwidth problems, etc.). Due to traditional Internet Protocol networks cannot handle this problem due to the rigidity of its architecture, software defined networks is introduced as a potential answer for resolving the existing challenges in video content delivery decoupling the control plane and data plane. Utilizing the unified perspective of the network, it is possible to develop a monitoring tool obtaining the network metrics to be used afterwards. In this paper, we propose the application of different clustering algorithms for monitoring software defined networks to validate the number of statistics queries decrements using the data and error rates to improve the network traffic and to reduce the overload. The simulations demonstrate that the expectation-maximization algorithm highly reduces the monitoring queries maintaining the best data and error rate values in the video delivery.

Attentional structuring, subjectivity, and the ubiquity of reflexive inner awareness

ABSTRACT Some have argued that a subject has an inner awareness of its conscious mental states by virtue of the non-introspective, reflexive awareness that any conscious state has of itself. But, what exactly is it like to have a ubiquitous and reflexive inner awareness of one’s conscious states, as distinct from one’s outer awareness of the apparent world? This essay derives a model of ubiquitous inner awareness (UIA) from Sebastian Watzl’s recent theory of attention as the activity of structuring consciousness into an experiential center and periphery. I develop Watzl’s theory into an account of UIA by suggesting that a subject is acquainted with its own conscious mental states through being reflexively aware of how these states are structured by attention into a unified subjective perspective. I favorably compare this Watzl-inspired account of UIA against other contemporary analytic and classical Buddhist accounts of reflexive awareness and subjective character, which variously ground the inner awareness of conscious states on their intrinsic phenomenal quality of ‘for-me-ness’, their affective/hedonic valence, or a subject’s disposition to introspect them. The Watzl-inspired account also accommodates possible counter-examples to Watzl’s theory posed by states of minimal phenomenal experience such as lucid dreamless sleep and non-dual meditative awareness.

A unified perspective of seismicity and fault coupling along the San Andreas Fault.

The San Andreas Fault (SAF) showcases the breadth of possible earthquake sizes and occurrence behavior; in particular, the central SAF is a microcosm of such diversity. This section also exhibits the spectrum of fault coupling from locked to creeping. Here, we show that the observations of aseismic slip, temporal clustering of seismicity, and spatial variations in earthquake size distributions are tightly connected. Specifically, the creep rate along the central SAF is shown to be directly proportional to the fraction of nonclustered earthquakes for the period 1984–2020. This relationship provides a unified perspective of earthquake phenomenology along the SAF, where lower coupling manifests in weaker temporal clustering, with repeating earthquakes as an end-member. This new paradigm provides additional justification for characterizing the northwest ∼75 kilometers of the creeping segment as a transition zone, with potential implications for seismic hazard.