Characterizations of distality via weak equicontinuity

For an infinite discrete group $G$ acting on a compact metric space $X$, we introduce several weak versions of equicontinuity along subsets of $G$ and show that if a minimal system $(X,G)$ admits an invariant measure then $(X,G)$ is distal if and only if it is pairwise IP$^*$-equicontinuous; if the product system $(X\times X,G)$ of a minimal system $(X,G)$ has a dense set of minimal points, then $(X,G)$ is distal if and only if it is pairwise IP$^*$-equicontinuous if and only if it is pairwise central$^*$-equicontinuous; if $(X,G)$ is a minimal system with $G$ being abelian, then $(X,G)$ is a system of order $\infty$ if and only if it is pairwise FIP$^*$-equicontinuous.Comment: 20 pages. To appear in Discrete and Continuous Dynamical Systems. arXiv admin note: text overlap with arXiv:2108.0127

The State of Digital Media Data Research, 2023

DMD Report website: https://mddatacoop.org/dmd/The purpose of this report is to provide an account of digital media data (DMD) research practices and to highlight its ongoing challenges. We define DMD as data that are collected, extracted, gathered, or scraped from a web-based platform such as a website, social networking site, mobile application, or another virtual space. We break these practices and their challenges into three stages—collection, analysis, and sharing. We argue that continuing digital media data (DMD) research should be guided by four principles: collaboration, transparency, preparation, and consistency. 1. COLLABORATION: Working together on protocols for DMD research can occur across all stages of the research pipeline, including setting norms for data sharing, producing baseline research, and co-developing archives. 2. TRANSPARENCY: Make code and data accessible to other researchers, when possible. Open-source software development is especially helpful for advancing research in a transparent manner. Given the cost for collecting, storing, and analyzing DMD, we also encourage researchers to provide these details in their publications. 3. PREPARATION: Researchers should anticipate the risks or challenges to collecting, analyzing, and reporting on DMD. Emerging methods for data collection, such as donated data, provide a new mechanism for studying user-consented data. 4. CONSISTENCY: We end with this principle because it builds on the aforementioned three as, when researchers are collaborative, transparent and prepared, research approaches will be more consistent, allowing us to compare across studies and identify situational contexts that require nuanced protocol.This work has been generously supported by the Social Science Research Council.Journalis

Probing the interaction of nanoparticles with small molecules in real time via quartz crystal microbalance monitoring

Y. Y. acknowledges University College London (UCL) for the Overseas Research Scholarship and the Graduate Research Scholarship. The project received funding from the European Unions Horizon 2020 research and innovation programme under grant agreement no. 633635 (DIACHEMO) and the EPSRC (grant number EP/J500549/1).Despite extensive advances in the field of molecular recognition, the real-time monitoring of small molecule binding to nanoparticles (NP) remains a challenge. To this end, we report on a versatile approach, based on quartz crystal microbalance with dissipation monitoring, for the stepwise in situ quantification of gold nanoparticle (AuNPs) immobilisation and subsequent uptake and release of binding partners. AuNPs stabilised by thiol-bound ligand shells of prescribed chemical composition were densely immobilised onto gold surfaces via dithiol linkers. The boronate ester formation between salicylic acid derivatives in solution and boronic acids in the AuNP ligand shell was then studied in real time, revealing a drastic effect of both ligand architecture and Lewis base concentration on the interaction strength. The binding kinetics were analysed with frequency response modelling for a thorough comparison of binding parameters including relaxation time as well as association rate constant. The results directly mirror those from previously reported in-depth studies using nuclear magnetic resonance spectroscopy. By achieving quantitative characterisation of selective binding of analytes with molecular weight below 300 Da, this new method enables rapid, low cost, rational screening of AuNP candidates for molecular recognition.Publisher PDFPeer reviewe

Predicting the response of three common subtropical tree species in China to climate change

IntroductionClimate is crucial factor influencing species distribution, and with global climate change, the potential geographic distribution of species will also alter. In this study, three subtropical tree species (Cunninghamia lanceolata, Pinus taiwanensis, and Quercus glauca) of great ecological values were selected as research objects.MethodsWe applied a maximum entropy (MaxEnt) to predict their potential distributions under different climate scenarios in both present and future conditions based on 37 environmental factors. Jackknife test was used in key factors affecting species distribution. In addition, we explored the key environmental variables that affect their distributions and revealed the evolutionary patterns and migration trends of these tree species under future climate.ResultsThe main findings are as follows: (1) Winter temperature, winter precipitation, and annual temperature range are identified as the key environmental variables affecting the potential geographic distribution of the three tree species; moreover, precipitation-related factors have a greater impact than temperature-related factors; (2) Currently suitable habitats for these three tree species are primarily located in subtropical China with decreasing suitability from south to north; (3) Under future climate conditions, the area of potentially suitable habitat for C. lanceolata continues to expand, while P. taiwanensis and Q. glauca tend to experience a reduction due to increasing greenhouse gas emissions over time; and (4) The centroid of suitable habitat for C. lanceolata shifts northward under future climate change, while the centroid of P. taiwanensis and Q. glauca move southward along with shrinking suitable habitat area.DiscussionOur predictions highlight a high risk of habitat loss of Q. glauca under climate change, recommending management and conservation references for these three commonly used afforestation species under current and future climate change scenarios in China