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Non-Hermitian systems with parity−time (PT)-symmetry have been extensively studied and rapidly developed in resonance wireless power transfer (WPT). The WPT system that satisfies PT-symmetry always has real eigenvalues, which promote efficient energy transfer. However, meeting the condition of PT-symmetry is one of the most puzzling issues. Stable power transfer under different transmission conditions is also a great challenge. Bound state in the continuum (BIC) supporting extreme quality-factor mode provides an opportunity for efficient WPT. Here, we propose theoretically and demonstrate experimentally that BIC widely exists in resonance-coupled systems without PT-symmetry, and it can even realize more stable and efficient power transfer than PT-symmetric systems. Importantly, BIC for efficient WPT is universal and suitable in standard second-order and even high-order WPT systems. Our results not only extend non-Hermitian physics beyond PT-symmetry, but also bridge the gap between BIC and practical application engineering, such as high-performance WPT, wireless sensing and communications.

•The Sydney Declaration revisits the essence of forensic science.•A definition and 7 fundamental principles provide a renewed foundational basis.•The trace is pivotal as a vestige, or remnant, of an investigated activity.•The case-based and retrodictive nature of forensic science is emphasised.•The principles underpin the practice and guide education and research. Unlike other more established disciplines, a shared understanding and broad acceptance of the essence of forensic science, its purpose, and fundamental principles are still missing or mis-represented. This foundation has been overlooked, although recognised by many forensic science forefathers and seen as critical to this discipline's advancement. The Sydney Declaration attempts to revisit the essence of forensic science through its foundational basis, beyond organisations, technicalities or protocols. It comprises a definition of forensic science and seven fundamental principles that emphasise the pivotal role of the trace as a vestige, or remnant, of an investigated activity. The Sydney Declaration also discusses critical features framing the forensic scientist’s work, such as context, time asymmetry, the continuum of uncertainties, broad scientific knowledge, ethics, critical thinking, and logical reasoning. It is argued that the proposed principles should underpin the practice of forensic science and guide education and research directions. Ultimately, they will benefit forensic science as a whole to be more relevant, effective and reliable.

The paper tries to demonstrate that the process of the increase of entropy does not explain the asymmetry of time itself because it is unable to account for its fundamental asymmetries, that is, the asymmetry of traces (we have traces of the past and no traces of the future), the asymmetry of causation (we have an impact on future events with no possibility of having an impact on the past), and the asymmetry between the fixed past and the open future, To this end, the approaches of Boltzmann, Reichenbach (and his followers), and Albert are analysed. It is argued that we should look for alternative approaches instead of this, namely we should consider a temporally asymmetrical physical theory or seek a source of the asymmetry of time in metaphysics. This second approach may even turn out to be complementary if only we accept that metaphysics can complement scientific research programmes.

Electrons of several hundred keV in Saturn's ring current are important seed components of the radiation belt. In this study, we have statistically analyzed the spatial distribution of energetic electrons on the equatorial plane of the inner magnetosphere based on the Cassini in situ observations. We found for all energy channels, the peak position of energetic electron flux shifts from the midnight sector to the afternoon sector as L shell increases. At specific L shells, the transitional energy (Et), which separates the peaks of energetic electron flux in azimuthal direction, decreases as L shell increases and is consistent with the theoretical prediction of corotation drift resonant energy (ECDR). Further analysis indicates that the day‐night asymmetry of energetic electron flux is caused by the noon‐to‐midnight electric field, with its direction deviates from the noon‐midnight line. These findings advance our understanding of the energization mechanism of inward radial transport.

In this article, three main approaches to situate forensic traces in time were revisited under the prism of the Sydney Declaration and adapted to be applicable to a large range of physical and digital traces. The first approach is based on time tags which are time-based characteristics produced as the result of an activity at a specific time. They can either be directly related to time (i.e., time stamps) or indirectly (i.e., time indicators). While relatively straightforward, time tags require scientific knowledge to be correctly interpreted and to account for the risks of desynchronisation, anomalies and manipulation. The second approach is based on time dynamics and aim at measuring changes that occur as a function of time, such as caesium pulsation (i.e., on which international atomic time is based) or body cooling after death (i.e., from which time since death can be inferred). However, time dynamics phenomena are generally also influenced by other case-specific factors (e.g., environmental factors), and thus more difficult to reliably implement in practice. Finally, the third approach relies on relative sequences, using information unrelated to time, such as relative positions or dynamics of traces at the scene. As each approach has its potential and limitations, a combination of traces from different (both material and digital) sources and approaches is recommended to answer time questions in practice (When? How long? In which succession?) and enhance the reliability of the dating endeavours. It is strongly recommended to consider the principles of the Sydney Declaration when implementing or developing dating methods, as they point at potential issues that are often forgotten in forensic research and practice, such as uncertainties linked to the concept of trace, scene investigation, the asymmetry of time, the importance of context and the multiplicity of purposes. Future research should focus on improving the reliability of these dating approaches by combining and systematising their usage in investigative practice, as well as in broader intelligence processes. [Display omitted] •Criminal activities occur in sequence and need to be chronologically reconstructed (Principle 3, 4).•Traces are fundamental vector of information including time related information (Principle 1).•The relative positions of traces at the scene contribute to the reconstruction (Principle 2, 7).•Even when commonly used in practice, dating endeavours must account for uncertainty (Principle 5).•Situating traces in time feed investigation, court and intelligences purposes (Principle 6).

Why do we have records of the past and not the future? Entropic explanations for this ‘record asymmetry’ have been popular ever since Boltzmann. Foremost amongst these is Albert and Loewer’s account, which explains the record asymmetry using a low-entropy initial macrostate (the ‘Past Hypothesis’) plus an initial probability distribution. However, the details of how this initial state underpins the record asymmetry are not fully specified. In this paper I attempt to plug this explanatory gap in two steps. First, I suggest the record asymmetry is more immediately explained by the ‘fork asymmetry’, which their picture omits. Second, by relating the fork asymmetry to an initial state that’s metaphysically similar to theirs, I clarify how this ultimately underpins the record asymmetry.

A striking feature of our world is that we only seem to have records of the past. To explain this ‘record asymmetry’, Albert and Loewer claim that the Past Hypothesis induces a narrow probability density over the world’s possible past macrohistories, but not its future macrohistories. Because we’re indirectly acquainted with this low-entropy initial macrostate, our observations of records allow us to exploit the associated narrow density to infer the past. I will argue that Albert and Loewer cannot make sense of why this probabilistic structure exists without falling back on the very records they wish to explain. To avoid this circularity, I offer an alternative account: the ‘fork asymmetry’ explains the record asymmetry, and this in turn explains the narrow density—not vice versa.

In the debate about the direction of time in physics, the concept of time reversal has been central. Tradition has it that time-reversal invariant laws are sufficient to state that the direction of time is non-fundamental or emergent. In this paper, we review some of the debates that have gravitated around the concept of time reversal and its relation to the direction of time. We also clarify some of the central concepts involved, showing that the very concept of time reversal is more complex than frequently thought.

Meteorological and environmental data that are collected at regular time intervals on a fixed monitoring network can be usefully studied combining ideas from multiple time series and spatial statistics, particularly when there are little or no missing data. This work investigates methods for modelling such data and ways of approximating the associated likelihood functions. Models for processes on the sphere crossed with time are emphasized, especially models that are not fully symmetric in space-time. Two approaches to obtaining such models are described. The first is to consider a rotated version of fully symmetric models for which we have explicit expressions for the covariance function. The second is based on a representation of space-time covariance functions that is spectral in just the time domain and is shown to lead to natural partially nonparametric asymmetric models on the sphere crossed with time. Various models are applied to a data set of daily winds at 11 sites in Ireland over 18 years. Spectral and space-time domain diagnostic procedures are used to assess the quality of the fits. The spectral-in-time modelling approach is shown to yield a good fit to many properties of the data and can be applied in a routine fashion relative to finding elaborate parametric models that describe the space-time dependences of the data about as well.

The azimuthal morphology of Earth’s ring currents has consistently shown asymmetry during extreme space weather events at low latitudes, particularly during geomagnetic storms. A dawn-dusk pattern has been detected during the storm main phase through near-Earth and in-situ magnetic measurements. This asymmetry is believed to arise from asymmetric solar wind-magnetosphere coupling and is linked to the closure of the ring current. Recent evidence has confirmed the existence of asymmetric ring currents during quiet times and the storm recovery phase. This phenomenon may be closely related to the evolution of ring currents, including plasma injection and decay processes. In this study, the local time asymmetry of the ring current is estimated using data from low-Earth-orbit Swarm and Macao Science Satellite-1 (MSS-1) missions. Spherical harmonics models are developed to quantify the magnetic field of ring currents through external Gauss coefficients during both quiet periods and the storm recovery phase. Several features of dawn-dusk asymmetry are observed in various cases in different months. (1) The maximum difference in magnetic value across local time ranges from 3 to 10 nT, showing relative invariance compared with various Sym-H levels. (2) Stronger magnetic signals are detected at the premidnight sector during quiet times and at the afternoon sector during the storm recovery phase. (3) Magnetic perturbations remain at a lower level during the post-midnight and morning sectors. Although the pattern of local time asymmetry differs between quiet times and the recovery phase, dawn-dusk asymmetry remains the most pronounced feature, affecting the trapping and loss of charged particles in the inner magnetosphere. Combining Swarm and MSS-1 magnetic observations can enable convenient monitoring of the detailed azimuthal local time effects of the ring current at various disturbance levels in the future.