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A large variety of complex systems in ecology, climate science, biomedicine and engineering have been observed to exhibit tipping points, where the dynamical state of the system abruptly changes. For example, such critical transitions may result in the sudden change of ecological environments and climate conditions. Data and models suggest that detectable warning signs may precede some of these dr
The synchronization of coupled oscillators is a fascinating manifestation of self-organization that nature uses to orchestrate essential processes of life, such as the beating of the heart. Although it was long thought that synchrony and disorder were mutually exclusive steady states for a network of identical oscillators, numerous theoretical studies in recent years have revealed the intriguing p
We propose a phenomenological model for the polygonal hydraulic jumps discovered by Ellegaard and co-workers, based on the known flow structure for the type-II hydraulic jumps with a "roller" (separation eddy) near the free surface in the jump region. The model consists of mass conservation and radial force balance between hydrostatic pressure and viscous stresses on the roller surface. In additio
Cancer results from a sequence of genetic and epigenetic changes that lead to a variety of abnormal phenotypes including increased proliferation and survival of somatic cells and thus to a selective advantage of precancerous cells. The notion of cancer progression as an evolutionary process has been attracting increasing interest in recent years. A great deal of effort has been made to better unde
A fundamental problem of asexual adaptation is that beneficial substitutions are not efficiently accumulated in large populations: Beneficial mutations often go extinct because they compete with one another in going to fixation. It has been argued that such clonal interference may have led to the evolution of sex and recombination in well-mixed populations. Here, we study clonal interference, and
We study a network of three populations of coupled phase oscillators with identical frequencies. The populations interact nonlocally, in the sense that all oscillators are coupled to one another, but more weakly to those in neighboring populations than to those in their own population. Using this system as a model system, we discuss for the first time the influence of network topology on the exist
We study a triangular network of three populations of coupled phase oscillators with identical frequencies. The populations interact nonlocally, in the sense that all oscillators are coupled to one another, but more weakly to those in neighboring populations than to those in their own population. This triangular network is the simplest discretization of a continuous ring of oscillators. Yet it dis
Spiral waves are ubiquitous in two-dimensional systems of chemical or biological oscillators coupled locally by diffusion. At the center of such spirals is a phase singularity, a topological defect where the oscillator amplitude drops to zero. But if the coupling is nonlocal, a new kind of spiral can occur, with a circular core consisting of desynchronized oscillators running at full amplitude. He
We analyze a large system of globally coupled phase oscillators whose natural frequencies are bimodally distributed. The dynamics of this system has been the subject of long-standing interest. In 1984 Kuramoto proposed several conjectures about its behavior; ten years later, Crawford obtained the first analytical results by means of a local center manifold calculation. Nevertheless, many questions
As the number of rapes is increasing in Sweden, and the number of individuals convicted of these crimes is decreasing, it is of importance to study offender characteristics of those committing these crimes and the circumstances in which these crimes are conducted, such as indoors or outdoors. Data from Swedish population-based registers were used to identify individuals suspected of rape, aggravat
Gun violence is a serious issue in many countries across the globe. It has been shown that there is an elevated risk for a further shooting nearby within a short time span of a shooting incident, so-called near-repeat patterning. The present study presents new evidence on near-repeat patterning in Sweden, with a focus on neighbourhoods which the police have labelled as ‘vulnerable’ – deprived neig
In this paper, we present a systematic approach to design a compact dual-mode monopole-like patch antenna using characteristic mode analysis (CMA). The modal analysis of a slotted circular patch structure incorporating a new shorting pin loading technique is presented. To achieve a compact monopole-like antenna with wideband operation, it is demonstrated that the first two significant modes with m
The design of two antenna ports for a compact Y-shaped patch on top of a square ground plane is considered in this work. Specifically, characteristic mode analysis reveals candidate regions to locate two direct probe feeding ports to jointly excite two significant modes of the Y-shaped patch with low mutual coupling and correlation. The feed design procedure, based on both the amplitude and phase
In modern aquaculture, animal-production technology is used to increase aquatic food sources. Such controlled rearing of seafood can, in principle, shift the pressure off wild stocks and aquatic ecosys- tems by reducing fishing activities, which may advance marine conservation goals. We examined resource displacement—the reduced consumption of a resource due to its replacement with a more environm
