San Mateo County Community College District

BACKGROUND:Bats are important reservoir hosts for a variety of pathogens, some of which are transmitted by ectoparasite vectors including mites, fleas, lice, ticks, and bat flies (families Nycteribiidae and Streblidae). All these ectoparasite taxa are known to parasitize two endemic fruit bats of Madagascar, Eidolon dupreanum and Rousettus madagascariensis. We aimed to describe the diversity of ectoparasite infestation for both bat species through morphological observation and DNA barcoding and elucidate ecological and climatic correlates of seasonal nycteribiid parasitism of these hosts. METHODS:Eidolon dupreanum and R. madagascariensis fruit bats were live-captured in northern and central-eastern Madagascar periodically from 2013 to 2020. Ectoparasites on all captured bats were counted and identified in the field and then collected into ethanol. Field identification of a subset of samples was confirmed via microscopy and DNA barcoding of the cytochrome C oxidase subunit 1 (COI) and 18S genes. The seasonal abundance of nycteribiid bat flies on both host bats was analyzed using generalized additive models, and the role of climate in driving this seasonality was assessed via cross-correlation analysis combined with generalized linear models. Phylogenetic trees were generated to compare COI and 18S sequences of Madagascar nycteribiid and streblid bat flies with available reference sequences from GenBank. RESULTS:Ectoparasites corresponding to four broad taxa (mites, ticks, fleas, and bat flies) were recovered from 628 of 873 E. dupreanum (71.9%) and 831 of 862 R. madagascariensis (96.4%). Eidolon dupreanum were most commonly parasitized by Cyclopodia dubia nycteribiids and R. madagascariensis by Eucampsipoda madagascariensis nycteribiids and Megastrebla wenzeli streblids. We observed significant seasonality in nycteribiid abundance on both bat hosts, which varied by bat sex and was positively correlated with lagged temperature, precipitation, and humidity variables. Barcoding sequences recovered for all three bat fly species grouped with previously reported sequences, confirming morphological species identification. Our study contributes the first DNA barcodes of any kind reported for M. wenzeli and the first 18S barcodes for C. dubia. CONCLUSIONS:This study explores the diversity and abundance of ectoparasite burdens in two Malagasy fruit bat species, highlighting the importance of seasonal ecology and the influence of climate variables on parasitism, which correlates with resource availability.

Azolla was collected and sequenced across California as a part of the California Conservation Genomics Project. We identify three major populations of Azolla in the state. Out of these groups, we are able to confidently identify one as Azolla filiculoides . The other two taxa are seemingly newly reported to California and are not the same as the taxa currently treated by the Jepson Manual; specifically, they are not members of the A. microphylla/mexicana clade. We infer patterns of Azolla genetic diversity across the state and the demographic histories of these populations. We find evidence that both isolation by distance and isolation by environment contribute to spatial genetic variation. Both of the two newly reported populations have demographic histories consistent with recent invasions of the state. However, we also discuss alternative possibilities and propose a roadmap for resolving the taxonomy of California Azolla . ### Competing Interest Statement The authors have declared no competing interest. University of California, RSI□19□690224

Azolla is a floating fern that has closely evolved with a vertically transmitted obligate cyanobacterium endosymbiont— Anabaena azollae —that performs nitrogen fixation in specialized Azolla leaf pockets. This cyanobac-terium has a greatly reduced genome and appears to be in the “advanced” stages of symbiosis, potentially evolving into a nitrogen-fixing organelle. However, there are also other lesser-known inhabitants of the leaf pocket whose role and mode of transmission are unknown. We sequenced 112 Azolla specimens collected across the state of California and characterized their metagenomes in order to identify the common bacterial endosymbionts of the leaf pocket and assess their patterns of co-diversification. Four taxa were found across all samples, establishing that there are multiple endosymbionts that consistently inhabit the Azolla leaf pocket. We found varying degrees of co-diversification across these taxa as well as varying degrees of isolation by distance and of pseudogenation, which implies that the endosymbiotic community is transmitted by a mix of horizontal and vertical mechanisms, and that some members of the microbiome are more facultative symbionts than others. These results show that the Azolla symbiotic community is complex, featuring members at potentially different stages of symbiosis evolution, further supporting the utility of the Azolla microcosm as a system for studying the evolution of symbioses.### Competing Interest StatementThe authors have declared no competing interest.

With the support from the US Department of Education through the Minority Science and Engineering Improvement Program (MSEIP). Four community engineering students have participated in the "Accelerated STEM Pathways through Internships, Research, Engagement, and Support" (ASPIRES) at San Francisco State University in summer 2018. This paper presents the summer intern project findings on collapse simulation of a one-bay-one-story steel frame developed in The Open System for Earthquake Engineering Simulation (OpenSees). Interns conducted the research on the model identification and uncertainty quantification of the modified Ibarra-Medina-Krawinkler (IMK) model. Through the presentation of Particle Swarm Optimization (PSO) and Markov Chain Monte Carlo (MCMC) analysis, the modified IMK model parameters are recognized and their uncertainty is quantified. This program provides mentorship for interns with the scientific research in earthquake engineering, and trains interns to integrate theory and practice, which serves preparation of their transition to a four-year university.

AbstractLiquid xenon time projection chambers are promising detectors to search for neutrinoless double beta decay (0$$\nu \beta \beta $$νββ), due to their response uniformity, monolithic sensitive volume, scalability to large target masses, and suitability for extremely low background operations. The nEXO collaboration has designed a tonne-scale time projection chamber that aims to search for 0$$\nu \beta \beta $$νββof$$^{136}$$136Xe with projected half-life sensitivity of$$1.35\times 10^{28}$$1.35×1028 yr. To reach this sensitivity, the design goal for nEXO is$$\le $$≤1% energy resolution at the decayQ-value ($$2458.07\pm 0.31$$2458.07±0.31 keV). Reaching this resolution requires the efficient collection of both the ionization and scintillation produced in the detector. The nEXO design employs Silicon Photo-Multipliers (SiPMs) to detect the vacuum ultra-violet, 175 nm scintillation light of liquid xenon. This paper reports on the characterization of the newest vacuum ultra-violet sensitive Fondazione Bruno Kessler VUVHD3 SiPMs specifically designed for nEXO, as well as new measurements on new test samples of previously characterised Hamamatsu VUV4 Multi Pixel Photon Counters (MPPCs). Various SiPM and MPPC parameters, such as dark noise, gain, direct crosstalk, correlated avalanches and photon detection efficiency were measured as a function of the applied over voltage and wavelength at liquid xenon temperature (163 K). The results from this study are used to provide updated estimates of the achievable energy resolution at the decayQ-value for the nEXO design.