Coastal dunes are found along the sandy coasts of oceans, seas, and large lakes all around the world. They are dynamic landforms that evolve along complex morphological and biological continua in ...response to a range on controls linked to climate, sea level, sediment movement, vegetation cover, and land use. By collating research across the full spectrum of processes shaping different types and sizes of dunes and smaller aeolian bedforms, special issues can aid researchers to identify new research directions and methods emerging from the discipline. This editorial summarizes the 25 contributions to the special issue Coastal dunes: links between aeolian processes and landform dynamics. We grouped the contributions into four broad themes: (1) long‐term dune evolution, (2) short‐term aeolian transport, (3) research methods, and (4) coastal dune management. Contributions to the special issue demonstrate that research interest in coastal dunes, and particularly the impacts of human interventions on dunes, continues to grow. It also shows how aeolian research on coastal dunes covers a range of temporal and spatial scales, from ripple dynamics and instantaneous airflow‐transport processes to dune field evolution with rising sea levels and large‐scale dune stage shifts. We highlight potential avenues for future research including vegetation roughness characteristics and their effect on wind flow and sediment transport, the challenges of upscaling short‐ and small‐scale results to larger and longer spatiotemporal scales, and the study of both natural and managed dune landscapes.
Novel methodological advances in coastal dune and aeolian process research include holographic camera systems, sediment samplers, uncrewed aerial vehicles (drones), and photography‐based sediment tracing. Large‐scale studies of coastal dune mobility are an excellent reminder that dunes respond quickly to natural and/or human pressures and comprise part of the wider nearshore–beach–dune continuum. Conflicting dune management practices can equally perceive bare sand as good and/or bad; migrating dunes as good and/or bad; and fully vegetated, stable dunes as good and/or bad.
Microglia are morphologically dynamic cells that rapidly extend their processes in response to various stimuli including extracellular ATP. In this study, we tested the hypothesis that stimulation of ...neuronal NMDARs trigger ATP release leading to communication with microglia. We used acute mouse hippocampal brain slices and two-photon laser scanning microscopy to study microglial dynamics and developed a novel protocol for fixation and immunolabeling of microglia processes. Similar to direct topical ATP application in vivo, short multiple applications of NMDA triggered transient microglia process outgrowth that was reversible and repeatable indicating that this was not due to excitotoxic damage. Stimulation of NMDAR was required as NMDAR antagonists, but not blockers of AMPA/kainate receptors or voltage-gated sodium channels, prevented microglial outgrowth. We report that ATP release, secondary to NMDAR activation, was the key mediator of this neuron-microglia communication as both blocking purinergic receptors and inhibiting hydrolysis of ATP to prevent locally generated gradients abolished outgrowth. Pharmacological and genetic analyses showed that the NMDA-triggered microglia process extension was independent of Pannexin 1, the ATP releasing channels, ATP release from astrocytes via connexins, and nitric oxide generation. Finally, using whole-cell patch clamping we demonstrate that activation of dendritic NMDAR on single neurons is sufficient to trigger microglia process outgrowth. Our results suggest that dendritic neuronal NMDAR activation triggers ATP release via a Pannexin 1-independent manner that induces outgrowth of microglia processes. This represents a novel uncharacterized form of neuron-microglial communication mediated by ATP.
This book gives a comprehensive and self-contained introduction to the theory of symmetric Markov processes and symmetric quasi-regular Dirichlet forms. In a detailed and accessible manner, Zhen-Qing ...Chen and Masatoshi Fukushima cover the essential elements and applications of the theory of symmetric Markov processes, including recurrence/transience criteria, probabilistic potential theory, additive functional theory, and time change theory. The authors develop the theory in a general framework of symmetric quasi-regular Dirichlet forms in a unified manner with that of regular Dirichlet forms, emphasizing the role of extended Dirichlet spaces and the rich interplay between the probabilistic and analytic aspects of the theory. Chen and Fukushima then address the latest advances in the theory, presented here for the first time in any book. Topics include the characterization of time-changed Markov processes in terms of Douglas integrals and a systematic account of reflected Dirichlet spaces, and the important roles such advances play in the boundary theory of symmetric Markov processes.
In some expensive multiobjective optimization problems (MOPs), several function evaluations can be carried out in a batch way. Therefore, it is very desirable to develop methods which can generate ...multipler test points simultaneously. This paper proposes such a method, called MOEA/D-EGO, for dealing with expensive multiobjective optimization. MOEA/D-EGO decomposes an MOP in question into a number of single-objective optimization subproblems. A predictive model is built for each subproblem based on the points evaluated so far. Effort has been made to reduce the overhead for modeling and to improve the prediction quality. At each generation, MOEA/D is used for maximizing the expected improvement metric values of all the subproblems, and then several test points are selected for evaluation. Extensive experimental studies have been carried out to investigate the ability of the proposed algorithm.
In this paper, we introduce and study fractional versions of the Bell–Touchard process, the Poisson-logarithmic process and the generalized Pólya–Aeppli process. The state probabilities of these ...compound fractional Poisson processes solve a system of fractional differential equations that involves the Caputo fractional derivative of order 0<β<1. It is shown that these processes are limiting cases of a recently introduced process, namely, the generalized counting process. We obtain the mean, variance, covariance, long-range dependence property, etc., for these processes. Further, we obtain several equivalent forms of the one-dimensional distribution of fractional versions of these processes.
Collaborations among researchers and across disciplinary, organizational, and cultural boundaries are vital to address increasingly complex challenges and opportunities in science and society. In ...addition, unprecedented technological advances create new opportunities to capitalize on a broader range of expertise and information in scientific collaborations. Yet rapid increases in the demand for scientific collaborations have outpaced changes in the factors needed to support teams in science, such as institutional structures and policies, scientific culture, and funding opportunities. The Science of Team Science (SciTS) field arose with the goal of empirically addressing questions from funding agencies, administrators, and scientists regarding the value of team science (TS) and strategies for successfully leading, engaging in, facilitating, and supporting science teams. Closely related fields have rich histories studying teams, groups, organizations, and management and have built a body of evidence for effective teaming in contexts such as industry and the military. Yet few studies had focused on science teams. Unique contextual factors within the scientific enterprise create an imperative to study these teams in context, and provide opportunities to advance understanding of other complex forms of collaboration. This review summarizes the empirical findings from the SciTS literature, which center around five key themes: the value of TS, team composition and its influence on TS performance, formation of science teams, team processes central to effective team functioning, and institutional influences on TS. Cross-cutting issues are discussed in the context of new research opportunities to further advance SciTS evidence and better inform policies and practices for effective TS.
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•Chlorophenols represent a threat to the environment and the human health.•Catalytic oxidation processes for the degradation of chlorophenols are reviewed.•Catalytic reduction ...processes for the degradation of chlorophenols are reviewed.•Principle and key issues are presented for each technology.•The most recent research studies in the field are summarized.
Although the water resource is not exhaustible, the water quality must be preserved. It does represent a major challenge for the coming decades. Since water is used for many different industrial, agricultural and domestic applications, a wide variety of waste effluents is being produced. Since conventional wastewater treatment plants, mainly based on biological processes, are poorly efficient for the treatment of toxic and/or non-biodegradable and/or highly concentrated effluents, new solutions are being looked for. Many different approaches have been investigated and catalytic processes may play a crucial role. Both oxidation and reduction processes for the treatment of chlorophenols have been reviewed. The principle of each of those processes is being described, the key parameters are identified and subsequently the major challenges to be overcome both in terms of material science and/or catalytic efficiency (activity and selectivity) are highlighted to offer a general but homogenized overview of the state-of-the-art in the different fields. Finally, the most recent developments in each field are shortly discussed.
We revisit the sequential rate-distortion (SRD) tradeoff problem for vector-valued Gauss-Markov sources with mean-squared error distortion constraints. Our study is partly motivated by the question ...recently raised in the paper "Rate-cost tradeoffs in control" (in Proc. 54th Annu. Allerton Conf. Commun., Control, Comput. , 2016, pp. 1157-1164) regarding the correctness of its solution algorithm known in the literature. We show via a counterexample that the dynamic reverse water-filling algorithm suggested by (15) of the paper "Stochastic linear control over a communication channel" ( IEEE Trans. Autom. Control , vol. 49, pp. 1549-1561, 2004) is not applicable to this problem, and consequently, the closed-form expression of the asymptotic SRD function derived in (17) of the paper "Stochastic linear control over a communication channel" ( IEEE Trans. Autom. Control , vol. 49, pp. 1549-1561, 2004) is not correct in general. Nevertheless, we show that the multidimensional Gaussian SRD function is semidefinite representable, and thus, it is readily computable.
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