79297 research outputs found
Sort by
PINCH: pipeline-informed noise characterization in LIGO’s third observing run
Get PDFWe present a method to identify and categorize gravitational wave candidate triggers identified by matched filtering gravitational wave searches (pipelines) caused by transient noise (glitches) in gravitational wave detectors using support vector machine (SVM) classifiers. Our approach involves training SVM models on pipeline triggers which occur outside periods of excess noise to distinguish between triggers caused by random noise and those induced by glitches. This method is applied independently to the triggers produced by the GstLAL search pipeline on data from the laser interferometer gravitational-wave observatory Hanford and Livingston observatories during the second half of the O3 observing run. The trained SVM models assign scores to ambiguous triggers, quantifying their similarity to triggers caused by random fluctuations, with triggers with scores above a defined threshold being classified as glitch-induced. Analysis of these triggers reveals the distinct impact of different glitch classes on the search pipeline, including their distribution in relevant parameter spaces. We use metrics such as the Bhattacharyya coefficient and an over-representation ratio to quantify the consistency and prevalence of glitch impacts over time and across parameter spaces. Our findings indicate that some glitch types consistently produce triggers in specific regions of the parameter space, while others generate triggers that are more widely distributed. We observe that Scattered Light glitches appear differently in the search pipeline before and after a commissioning change, demonstrating how such detector changes appear in the pipeline’s response to certain glitch classes. This method provides a framework for understanding and mitigating the influence of non-Gaussian transients on gravitational wave search pipelines, with implications for improving detection sensitivity and better understanding noise populations
Calibrating the Clock of JWST
Get PDFJWST, despite not being designed to observe astrophysical phenomena that vary on rapid timescales, can be an unparalleled tool for such studies. If timing systematics can be controlled, JWST will be able to open up the subsecond infrared timescale regime. Rapid time-domain studies, such as lag measurements in accreting compact objects and solar system stellar occultations, require both precise interframe timing and knowing when a time series begins, down to an absolute accuracy significantly below 1 s. In this work, we present two long-duration observations of the deeply eclipsing double white dwarf system ZTF J153932.16+502738.8, which we use as a natural timing calibrator to measure the absolute timing accuracy of JWST\u27s clock. From our two epochs, we measure an average clock accuracy of 0.12 ± 0.06 s, implying that JWST can be used for subsecond time-resolution studies down to the ∼100 ms level, a factor ∼5 improvement upon the prelaunch clock accuracy requirement. We also find an asymmetric eclipse profile in the F322W2 band, which we suggest has a physical origin
Anion Exchange Membrane Durability for Electrochemical CO2 Reduction in Membrane Electrode Assembly Cells
Get PDFThe electrochemical reduction of CO₂ using membrane electrode assembly (MEA) cells has emerged as a promising approach for carbon capture and conversion into valuable products. This study investigates the degradation mechanisms of anion exchange membranes (AEMs) in CO₂ reduction applications, focusing on Sustainion X37-50, PiperION, and FAA-3-50. The research analyzes the impact of chemical and mechanical degradation on membrane performance, highlighting key stability challenges in long-term operation. Fourier transform infrared spectroscopy (FTIR) and electrochemical impedance spectroscopy (EIS) were employed to monitor functional group stability and ionic conductivity loss over extended operation. The results indicate that hydroxide-induced degradation leads to nucleophilic substitution and Hofmann elimination, significantly reducing membrane conductivity over time. Mechanical tests further reveal structural weakening due to prolonged electrochemical cycling, with Young’s modulus and tensile strength declining substantially after extended exposure. To address the limitations of AEMs, this work explores the feasibility of non-charged porous membranes, such as polyvinylidene fluoride (PVDF), as alternatives for CO₂ electrolysis. Comparative Faradaic efficiency (FE) analysis between AEMs and non-charged membranes demonstrates that while AEMs enhance C₂ product formation, porous membranes can maintain similar selectivity for liquid-phase products. The reduced ethylene production with PVDF membranes suggests a shift in local reaction conditions and charge transport mechanisms, altering CO₂ reduction pathways on the Cu catalyst. Unlike anion exchange membranes (AEMs), which degrade under highly alkaline conditions due to chemical attacks on their functional groups, porous membranes are more resistant to degradation since they do not rely on fixed charged sites for ion conduction. Their ability to allow electrolyte penetration ensures sufficient ionic conductivity while maintaining structural integrity over prolonged use. This makes them a potential low-cost and durable solution for scaling up CO₂ electrolysis, particularly in systems where membrane degradation limits efficiency. Additionally, combining porous membranes with catalysts that enhance CO₂ solubility and reaction selectivity could lead to more efficient electrochemical conversion systems. As research progresses, these membranes could enable the development of more durable and commercially viable CO₂ electrolyzers, helping bridge the gap toward large-scale carbon utilization technologies
Evaluation of DIY Pest Management Strategies for the German Cockroach (Blattella germanica) in the Presence of Vitamin K Precursors and Synthetic Amorphous Silica
No full textThe German cockroach, Blattella germanica (Linnaeus) is a globally distributed indoor dwelling pest of medical concern. Insecticides are the preferred method of cockroach management due to their low cost, quick action, and availability. However, after continuous use, the development of insecticide resistance has emerged as a challenge for the pest management industry to effectively eliminate German cockroaches. Integrated pest management (IPM) is a sustainable framework which includes the use of glue board traps, vacuuming, in combination with different insecticide formulations such as sprays, gel or dust baits, and insecticide rotation has been successful for the management of German cockroaches. This framework also closely aligns with the One Health approach that interlinks human, animal, and environmental health.
Despite proven IPM methods for German cockroaches, because of the costs associated with management, homeowners often deploy various do-it-yourself (DIY) methods to mitigate pest infestations by purchasing over-the-counter aerosols, baits, bait stations, and inorganic dusts or create their own baits with a toxicant. However, these pest control strategies often fail due to lack of common pest knowledge, reduced active ingredient (AI) in consumer products, or physiological and behavioral resistance. However, there is limited research on evaluation of DIY methods that can effectively control the German cockroach infestations. Therefore, the overall goal of this study is to investigate homeowner DIY methods with safer alternatives for sustainable management of German cockroach. Specifically, it examines the relation between vitamin K precursors, which are reduced risk compounds with home foods with different nutritional balances. Next, we sought to identify synthetic amorphous silicas that are not used for pest management to test their efficacy. Finally, to improve amorphous silica efficacy vitamin K precursors and silicas were combined to determine if their efficacy at varying environmental humidity conditions could be improved, since dusts generally lose their potency at high moisture conditions. To complete this goal, my study has three objectives:
1) To understand the consumption of dry-flowable baits by conducting bioassays using vitamin K precursors (menadione and menadiol) mixed with different home available foods at 1%, 5%, 10%, 15%, and 20% concentrations using no choice and choice bioassays.
2) Screen different synthetic amorphous silica (SAS) for insecticidal activity against German cockroaches at different humidity levels (10%, 40%, 90%) in a continuous exposure vial bioassay.
3) Explore synergistic or additive interactions effects between amorphous silicas, and vitamin K precursors at 40% and 90% RH, using two different models to determine synergistic interactions.
By exploring reduced-risk insecticides with accessible food-based attractants and improving insecticidal dust efficacy at high humidity, this works aims to improve DIY pest control methods used by homeowners with a sustainable, safe, and cost-effective approach for German cockroach control
Butterfly species vary in sex-specific sodium accumulation from larval diets
Get PDFSodium is essential for animals, and its heterogeneous distribution can cause a range of phenomena, from sodium-seeking behaviours to impacting their performance. Although sodium content in soils and plants is relatively well documented, data for higher trophic levels are limited. Knowledge of the variation in sodium in lower trophic levels could have implications for understanding the behaviour and physiology of species at higher levels. We investigated the variation in tissue sodium concentration between males and females of four butterfly species. Puddling behaviour of Lepidoptera suggests sodium needs of males are generally greater than females, thus, we predicted males would accumulate more sodium than females on a given diet. Larvae were reared on plants (for Battus philenor, Chlosyne lacinia and Danaus plexippus) and an artificial diet (for Pieris rapae) under Low Na (no added sodium) and High Na (sodium added) conditions. Among species and sexes, we quantified and compared adult absolute tissue sodium concentrations and bioconcentration factors, which indicate net sodium accumulation or excretion relative to individuals\u27 diets. On average, individuals on low-sodium diets had higher bioconcentration values across all species. Male butterflies accumulated significantly higher sodium concentrations than females in two sodium treatments for B. philenor, and P. rapae and only in the High Na treatment for C. lacinia. However, in D. plexippus, individuals accumulate sodium in the High Na treatment, but males and females responded in the same way. Our study revealed sex- and species-specific patterns of butterfly sodium accumulation, which could be linked to variations in behaviour and/or performance. Differences in sodium content across species have implications for variation in predation and trophic-level interactions, an interesting avenue for future ecological and evolutionary research
CELLULAR AND MOLECULAR MECHANISMS OF INNATE IMMUNE RESPONSE MODULATED BY RESPIRATORY PNEUMOVIRUSES IN MACROPHAGES AND EPITHELIAL CELLS
No full textPneumoviruses are among the leading causes of viral respiratory infections in infants, elderly and immunocompromised patients. In the airways, alveolar macrophages form the first line of defense: they detect invading pathogens, produce type I and III interferons as well as pro-inflammatory cytokines, and coordinate antimicrobial activities. Upon viral challenge, macrophages rapidly sense pneumovirus components through pattern‐recognition receptors and mount a robust interferon response. Meanwhile, respiratory epithelial cells serve as the primary sites of viral replication and contribute to the innate immunity. Given the central roles of these two cell populations, this study investigates the molecular interplay that governs their antiviral functions. Specifically, we examine: (1) interferon induction in macrophages, (2) the antiviral activities of type I and type III Interferons, (3) the mechanisms of macrophage activation and cytokine regulation, and (4) the strategies by which pneumoviruses evade the molecular mechanism of antimicrobial control. Our findings shed light on the coordinated network of induction, activation, regulation and evasion events that determine infection outcome, and may inform the development of targeted interventions to bolster host resistance against pneumovirus-mediated disease
Zebra finches (Taeniopygia castanotis) display varying degrees of stress resilience in response to constant light
No full textThe ability for traits to recover after exposure to stress varies depending on the magnitude, duration, or type of stressor. One such stressor is circadian rhythm disruption stemming from exposure to light at night. Circadian rhythm disruption may lead to long-term physiological consequences; however, the capacity in which individuals recover and display stress resilience is not known. Here, we exposed zebra finches (Taeniopygia castanotis) to constant light (24L:0D) or a regular light/dark cycle (14L:10D) for 23 days, followed by a recovery period for 12 days. We measured body mass, corticosterone, and glucose levels at multiple timepoints, and relative protein expression of glucocorticoid receptors at euthanasia. Body mass significantly increased over time in light-exposed birds compared to controls, but a 12-day recovery period reversed this increase. Baseline levels of circulating glucose decreased in light-exposed birds compared to controls, but returned to pretreatment levels after the 12-day recovery period. In contrast, the glucose stress response did not show a similar recovery trend, suggesting longer recovery is needed or that this is a persistent effect in light-exposed birds. Surprisingly, we did not detect any differences in baseline corticosterone or reactivity of the hypothalamic-pituitiary-adrenal (HPA) axis between groups throughout the experiment. Moreover, we did not detect differences between relative protein expression of glucocorticoid receptors or a relationship with HPA axis reactivity. Yet, we found a positive relationship between glucocorticoid receptors and the glucose stress response, but only in the light group. Our results indicate that physiological and morphological traits differ in their ability to recover in response to constant light and warrants further investigation on the mechanisms driving stress resilience under a disrupted circadian rhythm
Shared and unique mechanisms of RNAi-mediated antiviral immunity in C. elegans
No full textSmall interfering RNAs (siRNAs), generated by Dicer proteins, play a pivotal role in antiviral immunity in eukaryotes. Dicer proteins also produce microRNAs (miRNAs), a class of endogenous small non-coding RNAs that regulate essential cellular functions through post-transcriptional mechanisms. In plants and insects, multiple Dicer proteins are produced and deployed to separately manage the biogenesis of antiviral siRNAs and miRNAs. This separation ensures that viral infections, especially the production of viral RNAi suppressors, do not severely compromise host growth or development. In contrast, nematode worms, such as Caenorhabditis elegans, rely on a single Dicer protein to produce both types of small RNAs. Probably as a strategy to mitigate the potential disruption of miRNA production by viral infections, nematodes have evolved distinct strategies for generating primary and secondary siRNAs for antiviral defense. This review explores the shared and unique features of siRNA-mediated antiviral immunity in Caenorhabditis elegans, shedding light on the specialized adaptations that enable robust antiviral defenses without compromising miRNA-mediated function
Synergistic toxicity of DBDPE and Cd in a microcosm agrosystem: Insights into physiological, biochemical, nutrient elements and amino acid metabolic responses
No full textAgricultural soil contamination by flame retardants and heavy metals has become an environmental concern, with decabromodiphenyl ethane (DBDPE) and cadmium (Cd) being frequently detected in e-waste dismantling areas. While previous studies mostly focused on single-organism system or individual toxicity, the combined effects of DBDPE and Cd on agricultural ecosystems remain largely unknown. This study aimed to reveal the joint toxicity mechanisms of DBDPE and Cd by examining physiological responses, amino acid metabolism, nutrient element distribution, and DBDPE degradation pathways in this integrated system. Results demonstrated that co-exposure to DBDPE and Cd intensified toxicity compared to single exposure. In lettuce, DBDPE amplified the inhibitory effects of Cd on plant growth (height and fresh weight of the aerial part decreased by 3.8 % and 5.8 %). Co-exposure inhibited chlorophyll synthesis (particularly carotenoid production, decreased by 53.33 %), disrupted amino acid metabolism, and impaired nutrient elements uptake, ultimately leading to reduced plant growth. In earthworms, co-exposure altered amino acid profiles, disrupted nutrient elements absorption and transport, thereby reducing their antioxidant defense capacity. Both organisms showed limited ability to detoxify DBDPE through similar debromination pathways. This study reveals the synergistic toxicological impacts of DBDPE and Cd in agricultural systems, highlighting the elevated ecological risks of their co-occurrence and emphasizing the need for comprehensive pollution control strategies in contaminated agricultural soils
A Visible-Light-Driven O-Glycosylation with Selenoglycosides Mediated by Chalcogen Bonding to Umemoto\u27s Reagent
No full textThe activation of chalcogenoglycosides for O-glycosylation typically involves strong electrophiles requiring low temperature. Herein, we demonstrate that visible-light irradiation of selenoglycosides in the presence of Umemoto\u27s reagent results in often high-yielding O-glycosylation. We provide evidence that this process is mediated by a novel mode of reactivity, specifically photoinduced electron transfer within a chalcogen-bonded complex