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1. Experimental Studies of Impact Resistance of Pressure-Sensitive Adhesives

   https://doi.org/10.1007/s11340-025-01176-z  

   Chambers, R_J; Li, R_J; Youssef, G.; Cai, S. (March 2025, Experimental Mechanics)

   Abstract BackgroundPressure-sensitive adhesives (PSAs) are integral to various industrial applications, yet a significant gap remains in accurately assessing their impact properties under dynamic conditions. This limitation hampers the optimization of PSAs for specific uses where impact resistance is critical. ObjectiveThis study aims to develop an experimental method to evaluate the impact properties of PSAs, providing a reliable and reproducible technique to assess their performance. MethodWe designed an experimental setup to simulate real-world impact conditions, incorporating high-speed cameras and an image analysis algorithm to capture the adhesive's behavior under sudden loads. The method's novelty lies in its ability to quantify maximum failure load and adhesion failure mechanisms in the dynamic loading of PSAs. ResultsThe experimental results reveal critical insights into the impact resistance of various PSA formulations, highlighting significant differences in energy dissipation and failure patterns. ConclusionThese findings offer new data not previously available in the literature, enabling a more precise evaluation of PSA performance. The developed method provides a robust framework for assessing the impact properties of PSAs, offering valuable guidance for the design and selection of adhesives in applications requiring enhanced impact resistance. This work bridges the gap between quasi-static testing and realistic dynamic performance, contributing to the advancement of PSA technology. 

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2. Rational homotopy type of projectivization of the tangent bundle of certain spaces

   https://doi.org/10.1108/AJMS-02-2024-0029  

   Gastinzi, Jean Baptiste; Ndlovu, Meshach (August 2024, Arab Journal of Mathematical Sciences)

   PurposeThe paper aims to determine the rational homotopy type of the total space of projectivized bundles over complex projective spaces using Sullivan minimal models, providing insights into the algebraic structure of these spaces. Design/methodology/approachThe paper utilises techniques from Sullivan’s theory of minimal models to analyse the differential graded algebraic structure of projectivized bundles. It employs algebraic methods to compute the Sullivan minimal model of $P(E)$and establish relationships with the base space. FindingsThe paper determines the rational homotopy type of projectivized bundles over complex projective spaces. Of great interest is how the Chern classes of the fibre space and base space, play a critical role in determining the Sullivan model ofP(E). We also provide the homogeneous space ofP(E)whenn = 2. Finally, we prove the formality ofP(E)over a homogeneous space of equal rank. Research limitations/implicationsLimitations may include the complexity of computing minimal models for higher-dimensional bundles. Practical implicationsUnderstanding the rational homotopy type of projectivized bundles facilitates computations in algebraic topology and differential geometry, potentially aiding in applications such as topological data analysis and geometric modelling. Social implicationsWhile the direct social impact may be indirect, advancements in algebraic topology contribute to broader mathematical knowledge, which can underpin developments in science, engineering, and technology with societal benefits. Originality/valueThe paper’s originality lies in its application of Sullivan minimal models to determine the rational homotopy type of projectivized bundles over complex projective spaces, offering valuable insights into the algebraic structure of these spaces and their associated complex vector bundles. 

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3. Spatial phylogenetics of Fagales: Investigating drivers of temperate forest distributions

   https://doi.org/10.1111/jbi.14840  

   Folk, R_A; Siniscalchi, C_M; Doby, J.; Kates, H_R; Manchester, S_R; Soltis, P_S; Soltis, D_E; Guralnick, R_P; Belitz, M. (April 2024, Journal of Biogeography)

   Abstract AimQuantifying the phylogenetic diversity of temperate trees is essential for understanding the processes that have shaped the modern distribution of temperate broadleaf forest and other major forest biomes. Here, we focus on Fagales, an iconic member of forests worldwide, to uncover global diversity and endemism patterns and investigate the distribution of root nodule symbiosis (RNS), an important morphological specialisation in this clade, as a key factor behind these patterns. LocationGlobal. TaxonFagales. MethodsWe combined phylogenetic data covering 60.2% of living species, fine‐scale distribution models covering 90% of species, and nodulation data covering all species to investigate the distribution of species richness and phylogenetic diversity at fine spatial scales compared to the distribution of RNS. We identify abiotic environmental factors associated with RNS and with Fagales diversity in general. ResultsWe find the highest species richness in temperate east Asia, eastern North America, and equatorial montane regions of Asia and Central America. By contrast, relative phylogenetic diversity (RPD) is highest at higher latitudes, where RNS also predominates. We found a strong spatial structuring of regionalisations of Fagales floras, reflecting distinct Northern and Southern Hemisphere floras (except a unique Afro‐Boreal region), each with distinct RNS‐environment relationships. Main ConclusionsAlthough species richness and phylogenetic regionalisation for Fagales accord well with traditional biogeographic concepts for temperate forests, this is not the case for RPD. RNS is almost universal in the highest RPD regions, which may reflect ecological filtering promoting RNS in these regions. Our results highlight the utility of global‐scale, clade‐specific spatial phylogenetics and its utility for understanding drivers of diversity in species‐rich clades. 

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4. Out of the temperate zone: A phylogenomic test of the biogeographical conservatism hypothesis in a contrarian clade of ants

   https://doi.org/10.1111/jbi.14462  

   Branstetter, Michael G.; Longino, John T.; Reyes‐López, Joaquín L.; Brady, Seán G.; Schultz, Ted R. (July 2022, Journal of Biogeography)

   Abstract AimThe standard latitudinal diversity gradient (LDG), in which species richness decreases from equator to pole, is a pervasive pattern observed in most organisms. Some lineages, however, exhibit inverse LDGs. Seemingly problematic, documenting and studying contrarian groups can advance understanding of LDGs generally. Here, we identify one such contrarian clade and use a historical approach to evaluate alternative hypotheses that might explain the group's atypical diversity pattern. We focus on the biogeographical conservatism hypothesis (BCH) and the diversification rate hypothesis (DRH). LocationGlobal. TaxonAnts (Hymenoptera: Formicidae: Stenammini). MethodsWe examined the shape of the LDG in Stenammini by plotting latitudinal midpoints for all extant, described species. We inferred a robust genome‐scale phylogeny using UCE data. We estimated divergence dates using beast2 and tested several biogeographical models inBioGeoBEARS. To examine diversification rates and test for a correlation between rate and latitude, we used the programs BAMM and STRAPP, respectively. ResultsStenammini has a skewed inverse LDG with a richness peak in the northern temperate zone. Phylogenomic analyses revealed five major clades and several instances of non‐monophyly among genera (Goniomma,Aphaenogaster). Stenammini and all its major lineages arose in the northern temperate zone. The tribe originated ~51 Ma during a climatic optimum and then diversified and dispersed southward as global climate cooled. Stenammini invaded the tropics at least seven times, but these events occurred more recently and were not linked with increased diversification. There is evidence for a diversification rate increase in HolarcticAphaenogaster + Messor, but we found no significant correlation between latitude and diversification rate generally. Main ConclusionsOur results largely support the BCH as an explanation for the inverse latitudinal gradient in Stenammini. The clade originated in the Holarctic and likely became more diverse there due to center‐of‐origin, time‐for‐speciation and niche conservatism effects, rather than latitudinal differences in diversification rate. 

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5. Spatial patterns of discovery points and invasion hotspots of non‐native forest pests

   https://doi.org/10.1111/geb.12988  

   Ward, Samuel_F; Fei, Songlin; Liebhold, Andrew_M; Keil, ed., Petr (August 2019, Global Ecology and Biogeography)

   Abstract AimEstablishments of non‐native forest pests (insects and pathogens) continue to increase worldwide with growing numbers of introductions and changes in invasion pathways. Quantifying spatio‐temporal patterns in establishment locations and subsequent invasion dynamics can provide insight into the underlying mechanisms driving invasions and assist biosecurity agencies with prioritizing areas for proactive surveillance and management. LocationUnited States of America. Time period1794–2018. Major taxa studiedInsecta, plant pathogens. MethodsUsing locations of first discovery and county‐level occurrence data for 101 non‐native pests across the contiguous USA, we (a) quantified spatial patterns in discovery points and county‐level species richness with spatial point process models and spatial hotspot analyses, respectively, and (b) identified potential proxies for propagule pressure (e.g., human population density) associated with these observed patterns. ResultsDiscovery points were highly aggregated in space and located in areas with high densities of ports and roads. Although concentrated in the north‐eastern USA, discovery points also occurred farther west and became less aggregated as time progressed. Invasion hotspots were more common in the north‐east. Geographic patterns of discovery points and hotspots varied substantially among pest origins (i.e., global region of pests’ native ranges) and pest feeding guilds. Significant variation in invasion richness was attributed to the patterns of first discovery locations. Data and shapefiles comprising analyses are provided. Main conclusionsUse of spatial point pattern analyses provided a quantitative characterization of the central role of human activities in establishment of non‐native pests. Moreover, the decreased aggregation of discovery points through time suggests that invasion pathways to certain areas in the USA have either been created or intensified by human activities. Overall, our results suggest that spatio‐temporal variability in the intensity of invasion pathways has resulted in marked geographic patterns of establishment and contributed to current macroscale patterns of pest invasion in the USA. 

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