Bibionomorpha is a large and diverse dipteran infraorder, of which its composition and family-level relationships have long been debated. In this study, we constructed a phylogenomic tree of Bibionomorpha using an extensive dataset of transcriptomic, genomic and anchored hybrid enrichment data. To further investigate the evolutionary timeline of the group, we also generated a fossil-calibrated time tree using data-driven calibration priors. Bibionomorpha, comprising Anisopodoidea, Bibionoidea, Scatopsoidea and Sciaroidea, is recovered as the sister group to Brachycera. Axymyiidae and Perissommatidae, which have been considered part of Bibionomorpha by some authorities, are instead recovered as sister to the Bibionomorpha + Brachycera. We discuss recalcitrant nodes within the infraorder, particularly regarding the placements of Bolitophilidae and Cecidomyiidae. Although tentative, phylogenetic network analysis suggests a possible reticulation event leading to Bolitophilidae, while mitochondrial data support a sex-specific hybridization event between ancestral Cecidomyiidae and Sciaridae + Diadocidiidae group. Time tree analyses suggest a Lower Triassic or deeper origin of Bibionomorpha, consistent with fossil evidence.
Phylogenetic conflict—particularly hidden gene-tree discordance generated by incomplete lineage sorting (ILS)—is pervasive in multilocus and phylogenomic datasets, yet its consequences for nucleotide substitution model selection remain poorly understood. Modern molecular studies increasingly collect and concatenate large sets of independent loci sampled across distant and often poorly characterized regions of the genome, creating significant potential for heterogeneity when analyzed in combination. Here, we examine whether intra-alignment genealogical conflict can influence standard model selection procedures to favor parameter-rich substitution models even when sequences evolve under a simple substitution process. Through a series of in silico case studies, we simulated sequence evolution under the simplest rate-homogeneous Jukes–Cantor (JC69) model and generated concatenated alignments as mosaics of multiple loci, each evolving on its own gene tree drawn under the multispecies coalescent. Conflict was increased by manipulating conditions expected to elevate ILS and gene-tree heterogeneity and embedding progressively more hidden genealogies within alignments while holding total alignment length constant. Despite all data being generated under JC69, model selection frequently favored more complex models, with varying sensitivity depending on the number of taxa, the expected amount of conflict, and the specific selection criterion applied. A dominant pattern was frequent inclusion of among-site rate variation parameters (+ G4 and/or + I), and under extreme conflict, model selection increasingly favored richer substitution models (e.g., SYM, GTR). Broadly, our results showed that hidden conflict can manifest as substitutional and rate heterogeneity, driving selection procedures to compensate with additional parameters in concatenated analyses under high conflict. Broadly, our study contributes to a greater understanding and appreciation of the challenges in modeling molecular evolution in the era of multilocus phylogenetics.
Detailed P- and S-wave velocity (Vp and Vs) models and relocated hypocenters are determined for the active New Madrid seismic zone based on inversion of local earthquake arrival time data in the Cooperative New Madrid seismic network catalog for the period 1 January 1997 through 5 July 2025. The data set consists of 5,609 earthquakes, 93,338 P-wave phases and 66,333 S-wave phases recorded at 59 stations. The velocity models provide much greater resolution than previous models and allow a more comprehensive interpretation of crustal velocity features. Crust south of the Reelfoot fault is part of the Missouri batholith. The Bootheel lineament is detected as well as a horst below Ridgely Ridge. The presence of the Reelfoot axial ring dike intrusion influences hypocenter locations in the Reelfoot fault. Most Reelfoot fault earthquakes north of the Axial fault occur within the intrusion, along the border of a negative Vs anomaly suggesting the presence of high pore-pressure fluids. South of the Axial fault, Reelfoot fault earthquakes occur in a low magnetic intensity portion of the intrusion and this segment is cut by northeast trending faults including the Axial, Cottonwood Grove, and Ridgely Ridge faults. We suggest that both strike-slip and reverse motion occur on the Reelfoot fault during large earthquakes. The portion of Reelfoot fault associated with the greatest amount of vertical uplift has sparse seismicity. This segment may be locked and pose elevated seismic hazard.
The use of fiber-reinforced polymers (FRPs) for strengthening existing reinforced concrete (RC) structures has significantly improved structural rehabilitation processes, providing efficient, durable, and non-invasive solutions. This study presents an advanced deep learning-based predictive model specifically developed to estimate the shear strength of concrete beams strengthened externally with carbon fiber-reinforced polymer (CFRP) composites. Using a comprehensive dataset of 216 experimentally tested CFRP-wrapped concrete beams drawn from existing research, a deep neural network model was rigorously optimized with the Optuna hyperparameter tuning framework and k-fold cross-validation to ensure robustness and generalizability. Model validation involved a thorough comparative analysis against established international design codes (ACI PRC-440.2-17, CSA-S806-12, JSCE) and a parametric study examining the sensitivity of shear strength predictions to key influencing factors, including concrete compressive strength, beam depth, and CFRP wrap thickness. Results demonstrated superior prediction accuracy and reliability of the deep learning approach compared to traditional empirical design models. Consequently, this research significantly enhances the precision of shear strength predictions for CFRP-strengthened concrete beams, supporting the development of more efficient and accurate structural rehabilitation and design guidelines.
