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Why parasites occur in certain hosts in certain locations has been a long-standing question among ecological and evolutionary parasitologists. Encounter and compatibility filters summarize the likelihood that a host and parasite will physically interact and establish an infection upon contact. Encounter and compatibility filters are not fixed and, among multiple locations, the abiotic environmental characteristics and biotic community composition that contribute to the filters often vary spatially and temporally. Abiotic variation may directly affect hosts or parasites —particularly parasites with one or more free-living stages— whereas the local biotic community may dilute or amplify parasite transmission. Unlike directly transmitted parasites, complex-life cycle parasites use multiple hosts, thus having life cycles that, we hypothesize, are highly susceptible to the effects of spatiotemporal environmental variation. We modeled infection probability relationships of endohelminths from post-metamorphic wood frogs (Rana [Lithobates] sylvatica) and northern leopard frogs (Rana pipiens) with wetland characteristics, landscape composition, and the anuran species within the local community. Parasites included complex-life cycle trematodes that use amphibians as definitive hosts (Haematoloechus spp., Glypthelmins quieta) or as intermediate hosts (Alaria sp., Neodiplostomum sp., echinostomatids, Lechriorchis) and nematodes with direct or indirect life cycles (Cosmocercoides, Oswaldocruzia). Although our results demonstrate that distributions of parasites with complex and direct life cycles are correlated with some abiotic and biotic characteristics of the environment, there were few general trends. Each parasite's distribution had its own unique relationship with wetland, landscape, and amphibian-community variables and there was overall low predictability for most species. One landscape feature — the number of wetlands within the vicinity of the site of amphibian capture — was commonly included in top models for leopard frogs and could be associated with how definitive hosts (e.g., amphibians, mammals, birds) and intermediate hosts (e.g., snails, odonates) use the landscape. The amphibian community at any given site also commonly affected infection probabilities, such that the local presence of other species tended to reduce infection probabilities in sampled frogs, lending support to the dilution effect at the landscape level. Our research highlights the need to consider spatiotemporal sampling, environmental variation, and host-community variation when studying parasite prevalence in any given component community. 

In this review we highlight recent advancements in mass spectrometry that have allowed for more efficient, robust, and rigorous enzyme engineering for various applications relating to natural products chemistry. 

Abstract Over a hundred gravitational-wave (GW) detections and candidates have been reported from the first three observing runs of the Advanced LIGO-Virgo-KAGRA (LVK) detectors. Among these, the most intriguing events are binary black hole mergers that result in a “lite” intermediate-mass black hole (IMBH) of ∼10²M_⊙, such as GW170502 and GW190521. In this study, we investigate 11 GW candidates from LVK’s third observing run with total detector-frame masses in the lite IMBH range. Using the Bayesian inference algorithmRIFT, we systematically analyze these candidates with three state-of-the-art waveform models that incorporate higher harmonics, which are crucial for resolving lite IMBHs in LVK data. For each candidate, we infer the premerger and postmerger black hole masses in the source frame, along with black hole spin projections across all three models. Under the assumption that these are binary black hole mergers, our analysis finds that five have a postmerger lite IMBH with masses ranging from 110 to 350M_⊙with over 90% confidence interval. Additionally, we note that one of their premerger black holes is within the pair-instability supernova mass gap (60–120M_⊙), and two premerger black holes are above the mass gap. Furthermore, we report discrepancies among the three waveform models in intrinsic parameters, with at least three GW candidates showing deviations beyond accepted statistical limits. While the astrophysical certainty of these candidates cannot be established, our study provides a foundation to probe the lite IMBH population that emerge within the low-frequency noise spectrum of LVK detectors. 

Polymer infiltration is studied in a bicontinuous, nanoporous gold (NPG) scaffold. For poly(2-vinylpyridine) (P2VP) with molecular weights (M_w) from 51k to 940k Da, infiltration is investigated in a NPG with fixed pore radius (R_p= 34 nm) under moderate confinement (Γ = R_g/R_p ) 0.18 to 0.78. The time for 80% infiltration (τ_(80%)) scales as M_w^1.43, similar to PS, but weaker than bulk behavior. Infiltration of P2VP is slower than PS due to stronger P2VP-wall interactions resulting in a physisorbed P2VP layer. This interpretation is supported by the similar scaling of τ_(80%) for P2VP and PS, as well as Molecular Dynamics (MD) simulations. Simulations show that infiltration time scales as M_w^1.43and that infiltration slows as the polymer-wall attraction increases. As M_w increases, the effective viscosity transitions from greater than to less than the bulk viscosity due to pore narrowing and a reduction entanglement density. These studies provide new insight for polymer behavior under confinement and a new route for preparing nanocomposites at high filler loadings. 

The nomenclature and status of the fossil-genus Sparganiaceaepollenites Thiergart 1937 and several of its species are problematic. We confirm the status of the genus and provide an emended description for it to accommodate new characters that were recently described in some species. We note that (i) the name Sparganiaceaepollenites microreticulatus Grabowska and Wa?y?ska 2009 from the Miocene of Poland is illegitimate according to the rules of the International Code of Nomenclature for algae, fungi, and plants, as a later homonym of Sparganiaceaepollenites microreticulatus Kar and Jain 1981 from the Miocene of India; (ii) the name Sparganiaceaepollenites reticulatus Samant et al. 2022 from the Maastrichtian of India is illegitimate as a later homonym of Sparganiaceaepollenites reticulatus Doktorowicz-Hrebnicka 1960 ex Krutzsch and Vanhoorne 1977 from the Miocene of Poland; and (iii) the name Sparganiaceaepollenites annulatus Thakre et al. 2024 from the Danian of India is illegitimate as a later homonym of Sparganiaceaepollenites annulatus De Benedetti 2023 from the Maastrichtian?Danian of Argentina. We propose the new names (i) Sparganiaceaepollenites oczkowicensis nom. nov. subst. pro Sparganiaceaepollenites microreticulatus Grabowska and Wa?y?ska; and (ii) Sparganiaceaepollenites intertrappeansis nom. nov. subst. pro S. reticulatus Samant et al. (an emended description is provided). Additionally, Sparganiaceaepollenites annulatus Thakre et al. is considered a heterotypic synonym of Sparganiaceaepollenites intertrappeansis nom. nov.