Non-breeding conditions induce carry-over effects on survival of migratory birds.

Identifying the processes that limit populations is a foundational objective of ecology and an urgent need for conservation. For migratory animals, researchers must study individuals throughout their annual cycles to determine how environmental conditions limit demographic rates within each period of the annual cycle and also between periods through carry-over effects and seasonal interactions.1,2,3,4,5,6 Our poor understanding of the rates and causes of avian migration mortality7 hinders the identification of limiting factors and the reversal of widespread avian population declines.8,9 Here, we implement new methods to estimate apparent survival (hereafter survival) during migration directly from automated telemetry data10 in Kirtland's Warblers (Setophaga kirtlandii) and indirectly from mark-recapture data in Black-throated Blue Warblers (S. caerulescens). Previous experimental and observational studies of our focal species and other migratory songbirds have shown strong effects of Caribbean precipitation and habitat quality on food availability,11,12,13,14 body condition,12,13,14,15,16,17,18,19 migration timing,11,12,15,16,20,21,22,23 natal dispersal,24,25 range dynamics,26 reproductive success,20,22,27 and annual survival.18,19,20,23,28,29,30,31 Building on this research, we test the hypotheses that environmental conditions during the non-breeding period affect subsequent survival during spring migration and breeding. We found that reduced precipitation and environmental productivity in the non-breeding period strongly influenced survival in both species, primarily by reducing survival during spring migration. Our results indicate that climate-driven environmental conditions can carry over to affect survival in subsequent periods and thus likely play an important role in year-round population dynamics. These lethal carry-over effects may be widespread and are likely magnified by intensifying climate change.

Recent Experience Affects Delay Discounting: Evidence across Temporal Framing, Signs, and Magnitudes.

Delay discounting, the decrease in outcome value as a function of delay to receipt, is an extensive area of research. How delays are framed (i.e., temporal framing), as well as the sign and magnitude of an outcome, produce important effects on the degree to which outcomes are discounted. Here, we examined how recent experience (i.e., order of presentation) modifies these well-known findings. Experiment 1 examined the effects of temporal framing across gains and losses. Regardless of outcome sign, the order of task presentation affected the effect of temporal framing. In particular, when typical delay frames (e.g., 1 week) preceded delays framed as actual dates (e.g., February 15), discounting was less in the date-framed task. However, when dates were followed by the delay frame, there was no difference in the degree of discounting. The experience of date-framed delays persisted or carried over to the delay-framed task. Experiment 2 examined recent experience and the magnitude effect. In particular, $10 and $100 were discounted similarly between-subjects when it was the first task completed. However, once participants completed the second magnitude task, the magnitude effect was present both within-subjects and across subjects. Furthermore, $10 was discounted more steeply when it followed $100, and $100 was discounted less steeply when it followed $10. The impact of recent experience on delay discounting has important implications for understanding mechanisms that may contribute to delay discounting. Recent experience should be considered when designing delay discounting experiments as well as when implementing interventions to reduce steep delay discounting.

Influence of global/local processing on perceived colour transparency.

Our cognitive processing is flexible and affected by global/local dominance in prior cognitive tasks. Similar to cognitive processing, perceptual processing, especially colour perception related to global/local processing, may be affected by prior global/local dominance; however, this possibility has not yet been assessed. Here, we examined whether prior tasks involving global/local processing influenced colour perception related to global/local processing. As colour perception is related to global/local processing, we focused on perceived colour transparency, in which a transparent layer is perceived in front of a background layer, even though these stimuli are physically in the same layer. When viewing the colour transparency stimulus, we expected that the perceived colour of a specific region, when focusing on only the local region, would differ from that when focusing on the whole image. In our study, the participants completed a global or local Navon task, followed by a colour-matching task that assessed how they saw colours using colour transparency stimuli. The degree of optical illusion (i.e., perceived colour transparency) after the global Navon task was greater than that after the local Navon task. Thus, prior global/local processing, a flexible mode of cognitive processing, influenced colour perception. This study provides new insight into perceptual flexibility, especially in colour perception.

Immediate and carry-over effects of late-spring frost and growing season drought on forest gross primary productivity capacity in the Northern Hemisphere.

Forests are increasingly exposed to extreme global warming-induced climatic events. However, the immediate and carry-over effects of extreme events on forests are still poorly understood. Gross primary productivity (GPP) capacity is regarded as a good proxy of the ecosystem's functional stability, reflecting its physiological response to its surroundings. Using eddy covariance data from 34 forest sites in the Northern Hemisphere, we analyzed the immediate and carry-over effects of late-spring frost (LSF) and growing season drought on needle-leaf and broadleaf forests. Path analysis was applied to reveal the plausible reasons behind the varied responses of forests to extreme events. The results show that LSF had clear immediate effects on the GPP capacity of both needle-leaf and broadleaf forests. However, GPP capacity in needle-leaf forests was more sensitive to drought than in broadleaf forests. There was no interaction between LSF and drought in either needle-leaf or broadleaf forests. Drought effects were still visible when LSF and drought coexisted in needle-leaf forests. Path analysis further showed that the response of GPP capacity to drought differed between needle-leaf and broadleaf forests, mainly due to the difference in the sensitivity of canopy conductance. Moreover, LSF had a more severe and long-lasting carry-over effect on forests than drought. These results enrich our understanding of the mechanisms of forest response to extreme events across forest types.

Semiparametric generalized estimating equations for repeated measurements in cross-over designs.

A model for cross-over designs with repeated measures within each period was developed. It was obtained using an extension of generalized estimating equations that includes a parametric component to model treatment effects and a non-parametric component to model time and carry-over effects; the estimation approach for the non-parametric component is based on splines. A simulation study was carried out to explore the model properties. Thus, when there is a carry-over effect or a functional temporal effect, the proposed model presents better results than the standard models. Among the theoretical properties, the solution is found to be analogous to weighted least squares. Therefore, model diagnostics can be made by adapting the results from a multiple regression. The proposed methodology was implemented in the data sets of the cross-over experiments that motivated the approach of this work: systolic blood pressure and insulin in rabbits.

Advanced maternal age has negative multigenerational impacts during Drosophila melanogaster embryogenesis.

Increasing maternal age is commonly accompanied by decreased fitness in offspring. In Drosophila melanogaster, maternal senescence negatively affects multiple facets of offspring phenotype and fitness. These maternal effects are particularly large on embryonic viability. Identifying which embryonic stages are disrupted can indicate mechanisms of maternal effect senescence. Some maternal effects can also carry-over to subsequent generations. We examined potential multi- and transgenerational effects maternal senescence on embryonic development in two laboratory strains of D. melanogaster. We categorized the developmental stages of embryos from every combination of old and young mother, grandmother and great grandmother. We then modelled embryonic survival across the stages and compared these models among the multigenerational maternal age groups in order to identify which developmental processes were most sensitive to the effects of maternal effect senescence. Maternal effect senescence has negative multigenerational effects on multiple embryonic stages, indicating that maternal provisioning and, possibly epigenetics, but not mutation accumulation, contribute to decreased offspring survival. This study shows the large, early and multi-faceted nature of maternal effects senescence in an insect population.

Reducing the source/sink ratio of grapevine to face global warming in a semi-arid climate: Effects on volatile composition of Cabernet Sauvignon grapes and wines.

The heterogeneity of the vineyard environment caused high variability in grape metabolites and flavor profiles, and the phenomenon was more prominent in recent years of climate change. Herein, distal leaf removal was applied in semi-arid Xinjiang to adjust the source to sink ratio of grapevines for three consecutive years (2018-2020). The grape-derived volatiles showed high correlations with specific climate factors such as temperature changes in the growth period. Results showed that distal leaf removal increased the solar radiation reaching the clusters in the first few days after applying LR treatments while not affecting the temperature. The improvement in fruity and floral aroma intensity by distal leaf removal was founded not only in grape metabolites but also in wines. Moderate cluster exposure brought by distal leaf removal was beneficial for the accumulation of isoprenoids, which therefore increased the fruity and floral intensity of wines. The carry-over effect did not show in consecutively defoliated vines among vintages regarding the wine aroma profile.

A note on point estimation and interval estimation of the relative treatment effect under a simple crossover design.

To increase power or reduce the number of patients needed for a parallel groups design, the crossover design has been often used to study treatments for noncurable chronic diseases. However, in the presence of carry-over effect caused by treatments, the commonly-used estimator which ignores the carry-over effect leads to a biased estimator for estimating the treatment effect difference. A two-stage test approach aimed to address carry-over effect proposed was found to be potentially misleading. In this paper, we propose a weighted average of the commonly-used estimator and an unbiased estimator that uses only the first period of the data. We derive an optimal weight that minimizes the mean squared error (MSE) and its modified estimator. We apply Monte Carlo simulation to evaluate the performance of the proposed estimators in a variety of situations. In the simulations, we examine the estimated MSE (EMSE), percentile interval length, and coverage probability calculated from the percentile intervals among considered estimators. Simulation results show that our proposed weighted average estimator and its modified estimator lead to smaller EMSEs on average comparing to the two commonly used estimators. The coverage probabilities using our proposed estimators are reasonably close to the nominal confidence level and the interval lengths are shorter comparing to the use of the unbiased estimator that uses only the first period of the data. We apply an example that was to evaluate the efficacy of two type of bronchodilators for asthma treatment to demonstrate the use of the proposed estimators.

Distal leaf removal made balanced source-sink vines, delayed ripening, and increased flavonol composition in Cabernet Sauvignon grapes and wines in the semi-arid Xinjiang.

Leaf removal applied in the upper canopy of modified vertical shooting positioning trellis system has been proposed as an effective strategy to mitigate the adverse effects of global warming on grape and wine quality. In this study, we removed the upper leaves of Cabernet Sauvignon canopy in a semi-arid climate for three consecutive years (2018-2020). About one-third of the whole canopy leaves were removed at the beginning of véraison (LR1) and post-véraison (LR2). All leaf removal treatments included two schemes: (i) leaf removal in the same vines in all vintages to investigate the carry-over effects (1-LR1 and 1-LR2); (ii) leaf removal in different vines in each vintage as repeated experiments among vintages (2-LR1 and 2-LR2). Results showed that leaf removal treatments significantly decreased total soluble solids accumulation in grapes without affecting titratable acidity and pH. LR1 treatments could delay ripening to 6.6 days on average, which was 2.6 days longer than LR2 treatments. LR treatments did not affect the yield but decreased soluble sugar content in canes. Leaves net assimilation rate showed no compensation for the loss of leaves. For phenolic composition, LR treatments increased flavonol concentration in both wines and grapes while had inconsistent effects on anthocyanins and flavanols over three seasons. Principal component analysis (PCA) showed that different LR treatment stages (LR1s vs LR2s) and whether LR in the same vines over consecutive years (1-LRs vs 2-LRs) had limited effects on phenolic profiles. In conclusion, LR in consecutive years at the upper canopy of grapevines was a practical strategy to face global warming in Xinjiang.

Early resources lead to persistent benefits for bumble bee colony dynamics.

Conditions experienced early in development can affect the future performance of individuals and populations. Demographic theories predict persistent population impacts of past resources, but few studies have experimentally tested such carry-over effects across generations or cohorts. We used bumble bees to test whether resource timing had persistent effects on within-colony dynamics over sequential cohorts of workers. We simulated a resource pulse for field colonies either early or late in their development and estimated colony growth rates during pulse- and non-pulse periods. During periods when resources were not supplemented, early-pulse colonies grew faster than late-pulse colonies; early-pulse colonies grew larger as a result. These results revealed persistent effects of past resources on current growth and support the importance of transient dynamics in natural ecological systems. Early-pulse colonies also produced more queen offspring, highlighting the critical nature of resource timing for the population, as well as colony, dynamics of a key pollinator.

Three-year hand hygiene monitoring and impact of real-time reminders on compliance.

BACKGROUND: Hand hygiene remains both the major strategy and an ongoing challenge for infection control. The main issues in the sustainability of hand hygiene automatic monitoring are healthcare worker (HCW) turnover rates and declining participation. AIM: To assess hand hygiene compliance and the impact of real-time reminders over three years. METHODS: HCW compliance was observed for the use of alcohol-based hand rubs (AHR) on room entry and exit. Linear multi-level mixed models with time autocorrelations were performed to analyse the repeated measurements of daily room compliance and the effect of reminders over eight quarters (24 months). FINDINGS: In all, 111 HCWs were observed and 525,576 activities were identified in the database. There was an improvement in compliance both on room entry and exit over two years, and the rooms which had activated reminders had better performance than the rooms which did not have activated reminders. CONCLUSIONS: This study showed the benefit of using real-time reminders; even 20% of rooms with an activated reminder improved overall hand hygiene compliance. A randomized real-time reminder setting may be a potential solution in reducing user fatigue and enhancing HCW self-awareness.

Within- and Trans-Generational Life History Responses to Diurnal Temperature Amplitudes of the Pupal Stage in the Diamondback Moth.

Diurnal temperature fluctuations in nature can have a significant effect on many ectodermic traits. However, studies on the effects of diurnal temperature fluctuations on organisms, especially the effects on specific life stages, are still limited. We examined the immediate effects of the same average temperature (25°C) and different temperature amplitudes (±4, ±6, ±8, ±10, ±12°C) on the development and survival of Plutella xylostella (Lepidoptera: Plutellidae). We also assessed carry-over effects on adult longevity, reproduction, development, and survival of offspring across generations. The effect of moderate temperature amplitudes was similar to that of constant temperature. Wide temperature amplitudes inhibited the development of pupae, reduced total reproduction, lowered intrinsic rates of population growth, and slowed the development and survival of eggs on the first day, but the proportion of females ovipositing on the first three days increased. Insects coped with the adverse effects of wide temperature amplitudes by laying eggs as soon as possible. Our results confirmed that a logistic model based on daily average temperature cannot predict development rates under wide temperature amplitudes. These findings highlight the effect of environmental temperature fluctuations at the pupal stage on the development and oviposition patterns of P. xylostella and should be fully considered when predicting field occurrence.

Transgenerational responses to seawater pH in the edible oyster, with implications for the mariculture of the species under future ocean acidification.

The majority of common edible oysters are projected to grow more slowly and have smaller impaired shells because of anthropogenic CO2-induced reductions in seawater carbonate ion concentration and pH, a process called ocean acidification (OA). Recent evidence has shown that OA has carryover effects, for example, larvae exposed to OA will also exhibit either positive or negative effects after metamorphosis. This study examined the hidden carryover effects of OA exposure during parental and larval stages on post-metamorphic traits of the commercially important oyster species Crassostrea hongkongensis. Adults of C. hongkongensis were exposed to control pH (pHNBS 8.0) and OA-induced low pH (pHNBS 7.4) conditions. Their larval offspring were then exposed to the same aquarium conditions before being out-planted as post-metamorphic juveniles at a mariculture site for 10 months. Initially, larval offspring were resilient to low pH with or without parental exposure. The larvae exposed to low pH had significantly faster development and higher percentage of settlement success compared to control groups. The out-planted juveniles with parental exposure had improved survival and growth compared to juveniles without parental exposure, regardless of the larval exposure history. This implies that transgenerational effects due to parental exposure not only persists but also have a greater influence than the within-generational effects of larval exposure. Our results shed light on the importance of linking the various life history stages when assessing the OA-induced carryover capacity of C. hongkongensis in the natural environment. Understanding these linked relationships helps us better predict the species rapid adaptation responses in the face of changing coastal conditions due to OA.

Long-term effects of combined botulinum toxin treatment and rehabilitation on upper limb muscle spasms: a case report.

[Purpose] We report our experience with a patient with a central spinal cord injury who showed improved finger and upper limb functions after long-term treatment with a combination of rehabilitation and botulinum toxin type A. [Participants and Methods] The patient had spasms and pain that gradually became more profound and was given botulinum toxin type A at 1 year 3 months after sustaining a spinal cord injury. We administered 14 botulinum toxin type A injections periodically for 7 years 4 months after the injury. We administered the injections at an average interval of 5.6 months. Splints that allowed extension and improved finger muscle tone and contracture were made for the patient. [Results] The patient experienced gradual alleviation of the spasms in the proximal upper limb muscles and improved range of motion after receiving five doses of botulinum toxin type A. The spasms and range of motion in the fingers gradually improved around 4 years after the injury through splint therapy and a combination of botulinum toxin type A administration and rehabilitation. [Conclusion] The combination of botulinum toxin type A, splint, and rehabilitation therapies can lead to positive improvements in finger spasticity and range of motion and is recommended for hypertonia cases with severe contractures.

Transgenerational plasticity of inducible defences: Combined effects of grand-parental, parental and current environments.

Phenotypic plasticity can occur across generations (transgenerational plasticity) when environments experienced by the previous generations influenced offspring phenotype. The evolutionary importance of transgenerational plasticity, especially regarding within-generational plasticity, is a currently hot topic in the plasticity framework. How long an environmental effect can persist across generations and whether multigenerational effects are cumulative are primordial-for the evolutionary significance of transgenerational plasticity-but still unresolved questions. In this study, we investigated how the grand-parental, parental and offspring exposures to predation cues shape the predator-induced defences of offspring in the Physa acuta snail. We expected that the offspring phenotypes result from a three-way interaction among grand-parental, parental and offspring environments. We exposed three generations of snails without and with predator cues according to a full factorial design and measured offspring inducible defences. We found that both grand-parental and parental exposures to predator cues impacted offspring antipredator defences, but their effects were not cumulative and depended on the defences considered. We also highlighted that the grand-parental environment did alter reaction norms of offspring shell thickness, demonstrating an interaction between the grand-parental transgenerational plasticity and the within-generational plasticity. We concluded that the effects of multigenerational exposure to predator cues resulted on complex offspring phenotypic patterns which are difficult to relate to adaptive antipredator advantages.

Timing of arrival in the breeding area is repeatable and affects reproductive success in a non-migratory population of blue tits.

Events in one part of the annual cycle often affect the performance (and subsequently fitness) of individuals later in the season (carry-over effects). An important aspect of this relates to the timing of activities. For example, many studies on migratory birds have shown that relatively late-spring arrival in the breeding area reduces both the likelihood of getting a mate or territory and reproductive success. In contrast, relatively little is known about the movements of individuals in non-migratory populations during the non-breeding season. Few studies have investigated the timing of arrival at the breeding area in such species, possibly due to the assumption that most individuals remain in the area during the non-breeding season. In this study, we used 4 years of data from a transponder-based automated recording system set up in a non-migratory population of blue tits Cyanistes caeruleus to describe individual variation in arrival at the breeding site. We investigated whether this variation can be explained by individual characteristics (sex, body size or status), and we assessed its effect on aspects of reproductive success in the subsequent breeding season. We found substantial variation in arrival date and demonstrate that this trait is individual-specific (repeatable). Females arrived later than males, but the arrival dates of social pair members were more similar than expected by chance, which suggests that individuals may mate assortatively depending on their arrival in the breeding area. Arrival predicted both whether an individual would end up breeding that season and several aspects of its breeding success. Our study suggests that individuals of non-migratory species leave the breeding area during the non-breeding season. Hence, it may be useful to consider variation in the scale of movements between breeding and non-breeding sites, rather than using a simple dichotomy between 'resident' and 'migratory' species. We conclude that the timing of pre-breeding events, in particular arrival date, may be an overlooked, but important, fitness-relevant trait in non-migratory species.

Stress across life stages: Impacts, responses and consequences for marine organisms.

Population dynamics of marine organisms are strongly driven by their survival in early life stages. As life stages are tightly linked, environmental stress experienced by organisms in the early life stage can worsen their performance in the subsequent life stage (i.e. carry-over effect). However, stressful events can be ephemeral and hence organisms may be able to counter the harmful effects of transient stress. Here, we analysed the published data to examine the relative strength of carry-over effects on the juvenile growth of marine organisms, caused by different stressors (hypoxia, salinity, starvation, ocean acidification and stress-induced delayed metamorphosis) confronted in their larval stage. Based on 31 relevant published studies, we revealed that food limitation had the greatest negative carry-over effect on juvenile growth. In the laboratory, we tested the effects of short-term early starvation and hypoxia on the larval growth and development of a model organism, polychaete Hydroides elegans, and assessed whether the larvae can accommodate the early stress to maintain their performance as juveniles (settlement and juvenile growth). Results showed that early starvation for 3 days (∼50% of normal larval period) retarded larval growth and development, leading to subsequent reduced settlement rate and juvenile growth. When the starvation period decreased to 1 day, however, the larvae could recover from early starvation through compensatory growth and performed normal as juveniles (c.f. control). Early exposure to hypoxia for 3 days did not affect larval growth (body length) and juvenile growth (tube length), but caused malformation of larvae and reduced settlement rate. We conclude that the adverse effects of transient stress can be carried across life stages (e.g. larval to juvenile stage), but depend on the duration of stressful events relative to larval period. As carry-over effects are primarily driven by energy acquisition, how food availability varies over time and space is fundamental to the population dynamics of marine organisms.

The Disjunction Effect in two-stage simulated gambles. An experimental study and comparison of a heuristic logistic, Markov and quantum-like model.

Savage's rational axiom of decision making under uncertainty, called the 'Sure Thing' principle, was purportedly falsified in a two-stage gamble paradigm by Tversky and Shafir (1992). This work revealed that participants would take a second-stage gamble for both possible outcomes of the initial-stage gamble, but would significantly depress this choice when no information was available on the outcome of the initial-stage gamble. Subsequent research has reported difficulty to replicate this Disjunction Effect in the two-stage gamble paradigm. We repeated this simulated two-stage gamble paradigm in an online study (N = 1119) but adapted the range of payoff amounts, and controlled the order of the blocks of two-stage gambles with, respectively without, information on the outcome of the first-stage gamble. The main empirical contributions of this study are that more risk averse participants produced (i) a reliable order effect in relation to the Disjunction Effect and the violation of the Law of Total Probability, and (ii) a novel inflation effect on gambling in the Unknown outcome condition analogous but opposite to the Disjunction Effect when Unknown outcome conditioned two-stage gambles precede the Known outcome conditioned ones. By contrast, we found that less risk averse participants produced neither of these effects. We discuss the underlying choice processes and compare the effectiveness of a logistic model, a Markov model and a quantum-like model. Our main theoretical findings are (i) a standard utility model and a Markov model using heuristic linear utility, contextual influence and carry-over effect cannot accommodate the present empirical results, and (ii) a model based on quantum dynamics, matched in form to the Markov model, can successfully describe all major aspects of our data.

Warm temperatures during cold season can negatively affect adult survival in an alpine bird.

Climate seasonality is a predominant constraint on the lifecycles of species in alpine and polar biomes. Assessing the response of these species to climate change thus requires taking into account seasonal constraints on populations. However, interactions between seasonality, weather fluctuations, and population parameters remain poorly explored as they require long-term studies with high sampling frequency. This study investigated the influence of environmental covariates on the demography of a corvid species, the alpine chough Pyrrhocorax graculus, in the highly seasonal environment of the Mont Blanc region. In two steps, we estimated: (1) the seasonal survival of categories of individuals based on their age, sex, etc., (2) the effect of environmental covariates on seasonal survival. We hypothesized that the cold season-and more specifically, the end of the cold season (spring)-would be a critical period for individuals, and we expected that weather and individual covariates would influence survival variation during critical periods. We found that while spring was a critical season for adult female survival, it was not for males. This is likely because females are dominated by males at feeding sites during snowy seasons (winter and spring), and additionally must invest energy in egg production. When conditions were not favorable, which seemed to happen when the cold season was warmer than usual, females probably reached their physiological limits. Surprisingly, adult survival was higher at the beginning of the cold season than in summer, which may result from adaptation to harsh weather in alpine and polar vertebrates. This hypothesis could be confirmed by testing it with larger sets of populations. This first seasonal analysis of individual survival over the full life cycle in a sedentary alpine bird shows that including seasonality in demographic investigations is crucial to better understand the potential impacts of climate change on cold ecosystems.