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UC Santa Cruz Previously Published Works

Cover page of Astrovirus and norovirus infections and their association with diarrheal symptoms in immunocompromised children

Astrovirus and norovirus infections and their association with diarrheal symptoms in immunocompromised children

(2026)

Human astroviruses are a common cause of viral gastroenteritis and are often underdiagnosed. While infections are typically mild or asymptomatic in immunocompetent hosts, astrovirus can cause prolonged and severe disease in immunocompromised individuals. Here, we conducted a case-control study to evaluate the clinical presentation of astrovirus infections in paediatric oncology patients. Our findings were compared to two groups: (1) norovirus infections in the same immunocompromised cohort, and (2) a cohort of immunocompetent children with and without diarrheal symptoms. Astrovirus was detected in 9.8% of immunocompromised patients, with prolonged shedding seen in multiple cases. Astrovirus infection was associated with an increased odds of diarrhoea, although this association weakened when adjusting for co-infections. In contrast, norovirus was not significantly associated with diarrhoea in immunocompromised patients, despite prolonged shedding in 24% of the cohort. High rates of co-infection with adenovirus and Clostridium difficile may have influenced symptom patterns. In the immunocompetent cohort, astrovirus was not associated with diarrhoea, while norovirus showed a strong association with symptoms. These findings indicate that astrovirus infections are more likely to cause diarrhoea in immunocompromised paediatric patients, while often asymptomatic in immunocompetent children. Norovirus showed the opposite trend, highlighting distinct roles of host immune status in shaping clinical outcomes. These findings highlight the importance of considering astrovirus as a potential contributor to gastrointestinal symptoms in immunocompromised children and call for broader diagnostic testing and further research on viral co-infections and persistence.

A case study in bias mitigation in teaching evaluations by changing the questions

(2026)

Bias in student teaching evaluations is a well-documented issue. As predicted in the literature, our campus found that changing questions to focus more on student direct observation and metacognitive reflection, as well changing to a frequency scale, was correlated with an increase in favorable ratings for instructors who are women or from under-represented populations. We compare data from a full year of an older question set to a full year of a revised question set. Our campus focuses on the percent of responses in the top two (of five) categories as a summary of student feedback. A logistic regression analysis shows that the gaps between populations of instructors change significantly over the time of the change in questions.

Cover page of Microplastic concentration and composition in surface waters and in stream-rearing Steelhead Trout (Oncorhynchus mykiss) in a rural coastal California stream

Microplastic concentration and composition in surface waters and in stream-rearing Steelhead Trout (Oncorhynchus mykiss) in a rural coastal California stream

(2026)

Microplastic (particles <5 mm) is an emerging environmental concern that threatens aquatic ecosystems worldwide. While extensive research has documented the ubiquity of microplastic in marine and coastal environments and its assimilation by organisms at all trophic levels, comparatively little is known about microplastic occurrence in rural riverine ecosystems. Even less information exists for salmon-bearing streams, where microplastic pollution may hinder salmonid conservation and recovery efforts. We examined the presence and concentration of microplastic in Scott Creek, a small coastal California (USA) watershed with minimal urban development. Our study quantified suspended microplastic in surface waters and in the gastrointestinal (GI) tracts of juvenile Steelhead Trout (Oncorhynchus mykiss). Microplastic was detected in 93 % of water samples, indicating that Scott Creek routinely transports and cycles microplastic. Concentrations were higher in late summer than in spring, although monthly spatial patterns were largely consistent among sites. In juvenile steelhead, 60.6 % of GI tracts contained one or more types of microplastic. For both surface waters and juvenile steelhead, microplastic was predominantly small (<5 mm) dark blue, black, and transparent fiber-type particles, with fragments, shards and foams encountered less frequently. These findings suggest that fish ingest microplastic at low frequencies, or that ingested particles may pass rapidly through their digestive systems. This study provides one of the first assessments of microplastic in a minimally urbanized, salmon-bearing watershed. Our results serve as a baseline for evaluating the ecological implications of microplastic pollution in small coastal creeks and its potential to influence native salmonid populations. Data Availability The surface water and steelhead microplastic datasets generated and analyzed during the current study are publicly available via Zenodo (DOI: 10.5281/zenodo.18038857).

Cover page of Does micro-irrigation save energy? An investigation in Gujarat, India

Does micro-irrigation save energy? An investigation in Gujarat, India

(2026)

Energy efficiency is a global priority, but investments in energy efficiency do not always deliver the expected benefits. This paper studies micro-irrigation systems (MIS), a technology thought to reduce the energy required for irrigation by as much as 70 percent. We installed individual meters to directly measure the energy consumption of several hundred farmers in Gujarat, India, and linked the meter data with survey data to yield a uniquely comprehensive view into energy use patterns in smallholder agriculture. We document two facts. One, energy use varies widely across farmers, and this variation is unexplained by factors such as farm area or village geography. Two, MIS users in our sample consume 30 to 40 percent more energy than non-users of MIS. This difference does not appear to be fully explained by observable differences across farmers nor by rebound effects, suggesting that the energy efficiency gains of MIS under real-world conditions may be disappointing. Our results highlight a need for increased attention to the details of implementation and further research into the actual benefits of resource-conserving technologies.

Characterizing the Role of Tau Tubulin Kinase 8.1 and 8.2 in C. elegans Spermatozoan Motility

(2026)

Cell motility is essential for processes such as immune responses, wound healing, and fertilization. Caenorhabditis elegans is an excellent model for studying sperm motility, due to the worm's transparency and high sperm production. C. elegans amoeboid sperm move by extending and retracting pseudopods, which are powered internally by the dynamic polymerization and depolymerization of the nematode Major Sperm Protein (MSP). Previous biochemical studies in the parasitic nematode Ascaris suum identified MSP polymerization-activating kinase (MPAK) as a key regulator of MSP assembly within the pseudopod. Here we investigate two C. elegans homologs, Tau Tubulin Kinase 8.1 (ttbk-8.1) and Tau Tubulin Kinase 8.2 (ttbk-8.2), that arose from a C. elegans-specific gene duplication. We generated both single and double knockout mutants; single knockout animals have fertility comparable to wildtype. Self-fertilizing double knockout (ttbk-8.1/2) hermaphrodites are severely sub-fertile, and males are completely infertile. ttbk-8.1/2 males successfully transfer sperm to females; however, their sperm cannot crawl to the site of fertilization. During sperm activation, ttbk-8.1/2 sperm undergo the two key events of sperm activation (membranous organelle fusion and pseudopod extension), however the process is abnormally slow. Furthermore, the resulting pseudopods are non-motile and abnormally smooth. Localization of key proteins to the pseudopods remains unaffected. TTBK-8.1/2 colocalizes with MSP to the fibrous bodies in mature spermatocytes, distributes throughout the cytoplasm in spermatids, and is confined to pseudopods of spermatozoa. These findings suggest an essential role for TTBK-8.1/2 in timely sperm activation and pseudopod motility.

Cover page of Delayed structural prediction for relative clauses: A new argument for learning to parse from Santiago Laxopa Zapotec

Delayed structural prediction for relative clauses: A new argument for learning to parse from Santiago Laxopa Zapotec

(2026)

Comprehenders in many of the world's languages exhibit a preference or a greater ease in comprehending transitive relative clauses (RCs) when associating the dislocated head with a subject position. Some theories relate this preference to an early prediction that an animate head will serve as a subject. We present a picture selection experiment with eye-tracking investigating the role of such predictions in comprehending transitive RCs in Santiago Laxopa Zapotec, an Oto-Manguean language of southern Mexico where RCs are ambiguous unless they contain a resumptive pronoun. Patterns of offline choices and incremental looking suggest that Santiago Laxopa Zapotec comprehenders avoid forming predictive interpretations of the RC head, and do not take its animacy into account in early processing. Instead, comprehenders exhibit a later, animacy-sensitive bias to interpret the RC-internal co-argument as a subject. Overall, we take this pattern as evidence that a comprehender's structural predictions must be somehow dependent on experience-based tuning, while more universal pressures like similarity-based interference remain fixed. The lingering question for theories of cross-linguistic processing is how much of our predictive mechanism is tunable: do we tune just the distribution of expected structures which directs predictions, or also the practice of deploying predictions itself? We discuss how either of these approaches might explain the pattern we observe in Santiago Laxopa Zapotec, and highlight that an answer to this question will depend on continued investigations across a diverse sample of the world's languages.

Cover page of Achieving Secure Routing within AutonomousSystems Independently of Routing Protocols

Achieving Secure Routing within AutonomousSystems Independently of Routing Protocols

(2026)

The protocols currently in place for routing within autonomous systems (ASes) of the Internet (e.g., OSPFv2, IS-IS, EIGRP and RIPv2) lack confidentiality and are  vulnerable to many cyber attacks. Traditional approaches to adopting security measures in routing protocols rely on either manual configuration of too many symmetric keys or using key-distribution methods that require trust in third parties and digital certificates.  This paper describes a new approach to secure  routing within ASes that does not make any changes to existing or future routing protocols and completely eliminates the need to use  IPsec, digital certificates, manual configuration of link-authentication secrets or passwords, or auxiliary key distribution systems. Trusted routers in the same autonomous system are configured with the same two secret integers, and  any two neighbor routers use those secrets to become cryptographically entangled in the use of  encryption keys to  provide message confidentiality, integrity, and cryptographic authentication. Experimental results show that the new approach to attain secure routing independently of existing or future routing protocols  introduces minimum delays for the encryption and decryption of signaling messages among routers.

Extension of the Pnictinous Acid Series: Rational Synthesis of a Stibinous Acid and Exploration of Its Reactivity

(2026)

Abstract The oxyacids of the heavy group 15 elements remain underexplored despite the important role that main-group oxyacids play in academic and industrial chemistry. Higher-valent oxyacids of heavier main-group elements readily polymerize because of their ability to expand their coordination spheres and the polarity of their terminal E–O (E = P, As, Sb, Bi) bonds. As a result, no free R2SbO2H stibinic acids have yet been prepared. Lower-valent R2SbOH stibinous acids should be less susceptible to such polymerization, but there are no reported rational syntheses of molecules belonging to this class. We report here the first controlled synthesis and isolation of a molecular stibinous acid, Dipp2SbOH, where Dipp = 2,6-diisopropylphenyl. We also report an initial exploration of the chemistry of this class of compounds, including their Brønsted acidity and Lewis basicity. The hydroxyl group of Dipp2SbOH is weakly acidic as probed via reaction with the very strong base DBU. We also prepared the analogous arsinous acid Dipp2AsOH and demonstrated that it can support oxidation to the well-defined monomeric arsinic acid Dipp2AsO2H. We therefore investigated the oxidation of Dipp2SbOH. Reaction with PhIO and H2O2 produced oxo-bridged clusters, suggesting the formation of a transient stibinic acid of the form Dipp2SbO2H.

Measurement of Charged-Particle Production in sNN=9.62 TeV Proton-Oxygen Collisions as a Probe of Cosmic-Ray Air Showers with the ATLAS Detector

(2026)

This Letter presents a measurement of prompt charged-particle production in proton-oxygen interactions at center-of-mass energy with the ATLAS detector, corresponding to of integrated luminosity. A total of selected events have at least one track with transverse momentum and pseudorapidity . The measured fiducial proton-oxygen cross section is and the extrapolated inelastic proton-air cross section is . Measurements of charged-particle multiplicity, , and distributions are an order-of-magnitude more precise than differences between hadronic-interaction models. These results enable improved modeling of cosmic-ray air showers, which is important for astroparticle physics.