Toxicity and behavioral effects of nootkatone, 1,10-dihydronootkatone, and tetrahydronootkatone to the formosan subterranean termite (Isoptera: Rhinotermitidae)

Toxicity and behavioral effects of nootkatone and two of its derivatives, 1,10-dihydronootkatone and tetrahydronootkatone, to Coptotermes formosanus Shiraki were investigated on workers from two different colonies by using topical application assays, repellency assays, and sand barrier assays. The acute toxicity of the nootkatones on workers from both colonies increased as the saturation of the molecule increased, but the difference was significant for only one colony. The results of the repellency assays showed a similar trend of efficiency; the threshold concentration for significant repellency was four-fold higher in nootkatone treatments (50 ppm) than in the reduced derivatives 1,10-dihydronootkatone or tetrahydronootkatone (12.5 ppm). In sand barrier assays, a concentration of 100 ppm of any of the three chemicals significantly reduced termite survival, tunnel building, and food consumption after a 12-d exposure. Termites preexposed tolOO ppm nootkatone-treated sand and placed in containers without nootkatone for 15 d continued to exhibit abnormal feeding and digging behaviors; survivorship, tunneling, and feeding activities were significantly reduced by 83.5, 63.2, and 95.4%, respectively. Termites pretreated for 12 d at concentrations of 50 and 75 ppm nootkatone and tetrahydronootkatone returned to normal digging activity after they were removed from the treatments, but their feeding activity was significantly reduced

Minke whales change their swimming behavior with respect to their calling behavior, nearby conspecifics, and the environment in the central North Pacific

This research was supported by the Office of Naval Research (Code 322, Award Number N0001422WX01263), Commander, U.S. Pacific Fleet (Code N465JR, Award Number N0007023WR0EP8F), and tool development necessary for this analysis was supported by the U.S. Navy’s Living Marine Resources Program (Award Number N0002520WR0141R). AcknowledgmentsBehavioral responses to sonar have been observed in a number of baleen whales, including minke whales (Balaenoptera acutorostrata). Previous studies used acoustic minke whale boing detections to localize and track individual whales on the U.S. Pacific Missile Range Facility (PMRF) in Kaua ‘i, Hawai‘i before, during, and after Navy training activities. These analyses showed significant changes in central North Pacific minke whale distribution and swimming behavior during Navy sonar events. For the purposes of contextualizing changes in animal movement relative to Navy sonar, we expanded on this research to examine the natural variation in minke whale movement when Navy sonar was not present. This study included 2,245 acoustically derived minke whale tracks spanning the years 2012–2017 over all months that minke whales were detected (October–May). Minke whale movement was examined relative to calling season, day of the year, hour of day, wind speed, calling state (nominal or rapid), and distance to the nearest calling conspecific. Hidden Markov models were used to identify two kinematic states (slower, less directional movement and faster, more directional movement). The findings indicate that minke whales were more likely to travel in a faster and more directional state when they were calling rapidly, when other vocalizing minke whales were nearby, during certain times of the day and calling seasons, and in windier conditions, but these changes in movement were less intense than the changes observed during exposure to Navy sonar, when swim speeds were the fastest. These results start to put behavioral responses to Navy sonar into an environmental context to understand the severity of responses relative to natural changes in behavior.Publisher PDFPeer reviewe

Core Body Temperatures in Intermittent Sports: A Systematic Review

Background: Hyperthermia (and associated health and performance implications) can be a significant problem for athletes and teams involved in intermittent sports. Quantifying the highest thermal strain (i.e. peak core body temperature [peak T c]) from a range of intermittent sports would enhance our understanding of the thermal requirements of sport and assist in making informed decisions about training or match-day interventions to reduce thermally induced harm and/or performance decline. Objective: The objective of this systematic review was to synthesise and characterise the available thermal strain data collected in competition from intermittent sport athletes. Methods: A systematic literature search was performed on Web of Science, MEDLINE, and SPORTDiscus to identify studies up to 17 April 2023. Electronic databases were searched using a text mining method to provide a partially automated and systematic search strategy retrieving terms related to core body temperature measurement and intermittent sport. Records were eligible if they included core body temperature measurement during competition, without experimental intervention that may influence thermal strain (e.g. cooling), in healthy, adult, intermittent sport athletes at any level. Due to the lack of an available tool that specifically includes potential sources of bias for physiological responses in descriptive studies, a methodological evaluation checklist was developed and used to document important methodological considerations. Data were not meta-analysed given the methodological heterogeneity between studies and therefore were presented descriptively in tabular and graphical format. Results: A total of 34 studies were selected for review; 27 were observational, 5 were experimental (2 parallel group and 3 repeated measures randomised controlled trials), and 2 were quasi-experimental (1 parallel group and 1 repeated measures non-randomised controlled trial). Across all included studies, 386 participants (plus participant numbers not reported in two studies) were recruited after accounting for shared data between studies. A total of 4 studies (~ 12%) found no evidence of hyperthermia, 24 (~ 71%) found evidence of ‘modest’ hyperthermia (peak T c between 38.5 and 39.5 °C), and 6 (~ 18%) found evidence of ‘marked’ hyperthermia (peak T c of 39.5 °C or greater) during intermittent sports competition. Conclusions: Practitioners and coaches supporting intermittent sport athletes are justified to seek interventions aimed at mitigating the high heat strain observed in competition. More research is required to determine the most effective interventions for this population that are practically viable in intermittent sports settings (often constrained by many competing demands). Greater statistical power and homogeneity among studies are required to quantify the independent effects of wet bulb globe temperature, competition duration, sport and level of competition on peak T c, all of which are likely to be key modulators of the thermal strain experienced by competing athletes. Registration: This systematic review was registered on the Open Science Framework (https://osf.io/vfb4s ; https://doi.org/10.17605/OSF.IO/EZYFA , 4 January 2021).Open Access funding enabled and organized by CAUL and its Member Institutions. Mitchell Henderson is supported by the Australian Government’s Research Training Program scholarship

Robust Henderson III estimators of variance components in the nested error model

Common methods for estimating variance components in Linear Mixed Models include Maximum Likelihood (ML) and Restricted Maximum Likelihood (REML). These methods are based on the strong assumption of multivariate normal distribution and it is well know that they are very sensitive to outlying observations with respect to any of the random components. Several robust altematives of these methods have been proposed (e.g. Fellner 1986, Richardson and Welsh 1995). In this work we present several robust alternatives based on the Henderson method III which do not rely on the normality assumption and provide explicit solutions for the variance components estimators. These estimators can later be used to derive robust estimators of regression coefficients. Finally, we describe an application of this procedure to small area estimation, in which the main target is the estimation of the means of areas or domains when the within-area sample sizes are small

Apparatus for a Search for T-violating Muon Polarization in Stopped-Kaon Decays

The detector built at KEK to search for T-violating transverse muon polarization in K+ --> pi0 mu+ nu (Kmu3) decay of stopped kaons is described. Sensitivity to the transverse polarization component is obtained from reconstruction of the decay plane by tracking the mu+ through a toroidal spectrometer and detecting the pi0 in a segmented CsI(Tl) photon calorimeter. The muon polarization was obtained from the decay positron asymmetry of muons stopped in a polarimeter. The detector included features which minimized systematic errors while maintaining high acceptance.Comment: 56 pages, 30 figures, submitted to NI