Proxy For Behavior Research Articles

Coral-reef fishes can become more risk-averse at their poleward range limits.

As climate warms, tropical species are expanding their distribution to temperate ecosystems where they are confronted with novel predators and habitats. Predation strongly regulates ecological communities, and range-extending species that adopt an effective antipredator strategy have a higher likelihood to persist in non-native environments. Here, we test this hypothesis by comparing various proxies of antipredator and other fitness-related behaviours between range-extending tropical fishes and native-temperate fishes at multiple sites across a 730 km latitudinal range. Although some behavioural proxies of risk aversion remained unaltered for individual tropical fish species, in general they became more risk-averse (increased sheltering and/or flight initiation distance), and their activity level decreased poleward. Nevertheless, they did not experience a decline in body condition or feeding rate in their temperate ranges. Temperate fishes did not show a consistently altered pattern in their behaviours across range locations, even though one species increased its flight initiation distance at the warm-temperate location and another one had lowest activity levels at the coldest range location. The maintenance of feeding and bite rate combined with a decreased activity level and increased sheltering may be behavioural strategies adopted by range-extending tropical fishes, to preserve energy and maintain fitness in their novel temperate ecosystems.

Abstract P022: MS #279 - Use Of Dietary Supplements And Risk Of Chronic Kidney Disease In The Hispanic Community Health Study/Study Of Latinos (HCHS/SOL)

Background: Dietary supplements (DS) are often used for their perceived health-promoting and therapeutic properties. Certain supplements can be nephrotoxic, especially among individuals at risk for chronic kidney disease (CKD). Hispanic/Latino populations are users of DS (30-70%) and have a high prevalence of conditions predisposing CKD. The potential contribution of DS use to risk of CKD in this population has not been studied. Objective: To assess whether DS use is associated with higher prevalence and incidence of CKD in Hispanic/Latinos. Methods: DS use was assessed in 16,279 of 16,415 Hispanic/Latinos enrolled in HCHS/SOL in 24-hour recall and 30-day medications inventory. Users of any DS were compared to those reporting no DS use. Prevalent CKD was defined with estimated glomerular filtration rate (eGFR) using the serum creatinine-cystatin C equation or urine albumin-to-creatinine ratio (ACR) ≥ 30 mg/g at baseline. Incident low eGFR and incident albuminuria at follow-up were defined as <60 mL/min/1.73 m 2 and ACR ≥ 30 mg/g, respectively. Incident CKD was defined as no prevalent CKD and incident low eGFR with eGFR decline ≥1ml/min/1.73 m 2 /year or incident albuminuria. We used multivariable logistic regression to estimate odds ratios (OR) for prevalence and Poisson regression for incidence rate ratios (IRR). Analyses accounted for HCHS/SOL complex sampling design. Results: DS users were older (median age 45 vs 35 years) and more likely to be female (57 vs 48%), have health insurance (54 vs 48%) and be born in the United States (26 vs 19%). Of DS users, 13% had prevalent CKD while 12% of non-DS users had prevalent CKD (adjusted OR 0.77 (95% CI 0.66, 0.91)). IRRs for incident CKD, low eGFR and albuminuria between users and non-users of DS were 1.0 (95% CI 0.84, 1.3), 0.87 (95% CI 0.61, 1.3), and 1.2 (95% CI 0.88, 1.6), respectively. Conclusions: DS use was associated with lower prevalent CKD at visit 1 and not associated with incident CKD, low eGFR or albuminuria at visit 2. DS use may be a proxy for health-seeking behavior in this population.

Preliminary Evidence That Circadian Alignment Predicts Neural Response to Monetary Reward in Late Adolescent Drinkers.

BackgroundRobust evidence links sleep and circadian rhythm disturbances to alcohol use and alcohol-related problems, with a growing literature implicating reward-related mechanisms. However, the extant literature has been limited by cross-sectional designs, self-report or behavioral proxies for circadian timing, and samples without substantive alcohol use. Here, we employed objective measures of sleep and circadian rhythms, and an intensive prospective design, to assess whether circadian alignment predicts the neural response to reward in a sample of late adolescents reporting regular alcohol use.MethodsParticipants included 31 late adolescents (18–22 y/o; 19 female participants) reporting weekly alcohol use. Participants completed a 14-day protocol including pre- and post-weekend (Thursday and Sunday) circadian phase assessments via the dim light melatonin onset (DLMO), in counterbalanced order. Sleep-wake timing was assessed via actigraphy. Circadian alignment was operationalized as the DLMO-midsleep interval; secondary analyses considered social jet lag based on weekday-weekend differences in midsleep or DLMO. Neural response to reward (anticipation and outcome) was assessed via a monetary reward fMRI task (Friday and Monday scans). Alcohol use was assessed at baseline and via ecological momentary assessment. Mean BOLD signal was extracted from two regions-of-interest (striatum and medial prefrontal cortex, mPFC) for analyses in regression models, accounting for age, sex, racial identity, and scan order.ResultsIn primary analyses, shorter DLMO-midsleep intervals (i.e., greater misalignment) on Thursday predicted lower striatal and mPFC responses to anticipated reward, but not reward outcome, on Friday. Lower neural (striatum and mPFC) responses to anticipated reward on Friday correlated with more binge-drinking episodes at baseline, but were not associated with alcohol use in the post-scan weekend. In secondary analyses, greater social jet lag (particularly larger weekend delays in midsleep or DLMO) was associated with lower neural responses to reward anticipation on Monday.ConclusionFindings provide preliminary evidence of proximal associations between objectively determined circadian alignment and the neural response to anticipated monetary reward, which is linked in turn to patterns of problematic drinking. Replication in a larger sample and experimental designs will be important next steps to determining the extent to which circadian misalignment influences risk for alcohol involvement via alterations in reward function.

The utility of intention as a proxy for sustainable buying behavior – A necessary condition analysis

Sustainable buying behavior has increasingly received attention from academia and practitioners alike. While research in this field commonly relies on the theory of planned behavior (TPB), previous studies have not been able to clarify the utility of purchase intention as a proxy for sustainable buying behavior and systematically neglect the role of social sustainability aspects. To advance the theoretical understanding of sustainable consumption, we investigate buying behavior with regard to the sustainable clothing purchases of 2000 consumers in Germany using necessary condition analysis (NCA). The results empirically confirm the utility of intention as a proxy for sustainable buying behavior. Further, we find that social concerns and the perceived knowledge of social issues are essential drivers of purchase intention. In addition to extending the theoretical understanding of the roles of intention and social aspects in the TPB framework, we derive practical implications for managers seeking to facilitate sustainable consumption.

Using Google Trends as a proxy for occupant behavior to predict building energy consumption

In recent years, the availability of larger amounts of energy data and advanced machine learning algorithms has created a surge in building energy prediction research. However, one of the variables in energy prediction models, occupant behavior, is crucial for prediction performance but hard-to-measure or time-consuming to collect from each building. This study proposes an approach that utilizes the search volume of topics (e.g., education or Microsoft Excel) on the Google Trends platform as a proxy of occupant behavior and use of buildings. Linear correlations were first examined to explore the relationship between energy meter data and Google Trends search terms to infer building occupancy. Prediction errors before and after the inclusion of the trends of these terms were compared and analyzed based on the ASHRAE Great Energy Predictor III (GEPIII) competition dataset. The results show that highly correlated Google Trends data can effectively reduce the overall RMSLE error for a subset of the buildings to the level of the GEPIII competition’s top five winning teams’ performance. In particular, the RMSLE error reduction during public holidays and days with site-specific schedules are respectively reduced by 20–30% and 2–5%. These results show the potential of using Google Trends to improve energy prediction for a portion of the building stock by automatically identifying site-specific and holiday schedules.

Face mask mandates and risk compensation: an analysis of mobility data during the COVID-19 pandemic in Bangladesh

IntroductionConcerns have been raised about the potential for risk compensation in the context of mask mandates for mitigating the spread of COVID-19. However, the debate about the presence or absence...

Informing spread predictions of two alien snails using movement traits

Invasive alien species are a growing global problem, and aquatic ecosystems have been regarded as particularly vulnerable. Biological invasions can alter ecosystem functioning, threaten native biodiversity and burden the global economy. Understanding alien species ability to disperse via locomotion following arrival to new environments is critical for prediction of spread rates. Here, we quantified in-field densities and compared movement traits between two widespread invasive alien snails, Tarebia granifera and Physa acuta. We measured the: (i) net distance and velocity to determine dispersal potential; and (ii) turning angles (both absolute and relative) and straightness index as proxies for exploratory behaviour. Tarebia granifera exhibited a significantly greater velocity and covered a significantly larger net distance (i.e., greater spread rate) than Physa acuta. In-field densities were marked for both species (T. granifera: mean 351 individuals m−2; P. acuta: mean 235 individuals m−2), but differed spatially. The exploratory behavior (i.e., mean or absolute turning angles and straightness index) did not differ significantly between the two alien species; both species showed a slight tendency to turn counterclockwise. The present study suggests a more rapid capacity to self-disperse in T. granifera than P. acuta, which could facilitate rapid spread within and between aquatic systems. Thus, this current study highlights the often-overlooked role of animal behaviour in promoting invasion; this autecological information can help inform predictive models for the spread of alien snails within freshwater ecosystems.

Return of the lysergamides. Part VII: Analytical and behavioural characterization of 1-valeroyl-d-lysergic acid diethylamide (1V-LSD).

The psychopharmacological properties of the psychedelic drug lysergic acid diethylamide (LSD) have attracted the interest of several generations of scientists. While further explorations involving novel LSD-type compounds are needed to assess their potential as medicinal drugs, the emergence of novel derivatives as recreational drugs has also been observed. 1-Valeroyl-LSD (also known as 1-valeryl-LSD, 1-pentanoyl-LSD, 1V-LSD, or "Valerie") is a new N1 -acylated LSD derivative that recently appeared on the online market, and it could be viewed as a higher homolog of ALD-52, 1P-LSD, and 1B-LSD. The present study included the analytical characterization and involved various methods of mass spectrometry (MS), gas and liquid chromatography (GC and LC), nuclear magnetic resonance (NMR) spectroscopy, GC-solid-state infrared (GC-sIR) analysis, and Raman spectroscopy. The in vivo activity of 1V-LSD was assessed using the mouse head-twitch response (HTR), a 5-HT2A -mediated head movement that serves as a behavioral proxy in rodents for human hallucinogenic effects. Similar to LSD and other psychedelic drugs, the HTR induced by 1V-LSD was dose dependent, and the median effective dose for 1V-LSD was 373 nmol/kg, which was about a third of the potency of LSD (ED50 = 132.8nmol/kg). Lysergamides containing the N1 -substituent typically act as weak partial agonists at the 5-HT2A receptor and are believed to serve as prodrugs for LSD. 1V-LSD is also likely to be hydrolyzed to LSD and serve as a prodrug, but studies to assess the biotransformation and receptor pharmacology of 1V-LSD should be performed to fully elucidate its mechanism of action.

PSV-16 Validation of an algorithm to assess feedbunk replacement events in beef cattle using an electronic feeding system

Abstract Visual observations of social behavior and dominance relationships in cattle have been used to examine associations with productivity and well-being. This method is time consuming limiting the number of animals that can be evaluated. The objective of this study was to validate an algorithm to quantify feedbunk replacement events using data from an electronic feeding system. Crossbred beef steers (n = 20) fed a grower diet were housed in 1 of 2 pens each equipped with 3 electronic feedbunks (GrowSafe Systems) and video recorders. A trained video observer recorded all feedbunk replacement events and other agonistic activities at the feedbunk over a 4-d period (24 h/d). The electronic feeding system recorded the start and end timestamps of bunk visit (BV) events for each animal. An algorithm was developed to determine BV events deemed to be replacement events, defined as a BV event when an actor animal displaced a reactor animal from the feedbunk and occupied the same feeder within a specified period of time (replacement criterion). We calculated the recall and precision corresponding to replacement criterions from 1 to 60 s, and the optimum replacement criterion was determined to be between 18 and 20 s. The recall, precision and F-score of the algorithm using this replacement criterion were high (on average > 0.75). Furthermore, a replacement competition index was computed as a proxy for competitive feedbunk behavior, calculated as the number of actor-initiated replacement events divided by the total number of replacement events for each steer. Using Spearmans rank correlation we found high correlations (r > 0.7; P < 0.05) between the electronic and observed indices. These preliminary results demonstrate the potential of the GrowSafe system to quantify feedbunk replacement events for confined beef cattle, providing opportunities to evaluate associations between competitive feedbunk behavior and economically relevant traits.

Impact of wagering inducements on the gambling behaviors of on-line gamblers: A longitudinal study based on gambling tracking data.

AimsTo estimate whether the use of wagering inducements has a significant impact on the gambling behaviors of on‐line gamblers and describe this temporal relation under naturalistic conditions.DesignThis longitudinal observational study is part of the second stage of the Screening for Excessive Gambling Behaviors on the Internet (EDEIN) research program.SettingGambling tracking data from the French national on‐line gambling authority (poker, horse race betting and sports betting) and from the French national lottery operator (lotteries and scratch games).ParticipantsA total of 9306 gamblers who played poker, horse race or sports betting and 5682 gamblers who played lotteries and scratch games completed an on‐line survey. The gender ratio was largely male (between 87.1% and 92.9% for poker, horse race betting and sports betting, and equal to 65.1% for lotteries). Median age ranged from 35 (sports betting) to 53 (horse race betting and lotteries).MeasurementsThe survey used the Problem Gambling Severity Index (PGSI) to determine the status of the gamblers (at‐risk or not). Gambling tracking data included weekly gambling intensity (wagers, deposits), gambling frequency (number of gambling days), proxies of at‐risk gambling behaviors (chasing and breadth of involvement) and use of wagering inducements.FindingsThe use of wagering inducements was associated with an increase of gambling intensity [β between −0.06 (−0.08; –0.05) and 0.57 (0.54; 0.60)], gambling frequency [β between 0.12 (0.10; 0.18) and 0.29 (0.28; 0.31)] and at‐risk gambling behaviors [odds ratio between 1.32 (1.16; 1.50) and 4.82 (4.61; 5.05)] at the same week of their use. This effect was stronger for at‐risk gambling behaviors and at‐risk gamblers.ConclusionsWagering inducements may represent a risk factor for developing or exacerbating gambling problems.

Attractiveness of female sexual signaling predicts differences in female grouping patterns between bonobos and chimpanzees

Here we show that sexual signaling affects patterns of female spatial association differently in chimpanzees and bonobos, indicating its relevance in shaping the respective social systems. Generally, spatial association between females often mirrors patterns and strength of social relationships and cooperation within groups. While testing for proposed differences in female-female associations underlying female coalition formation in the species of the genus Pan, we find only limited evidence for a higher female-female gregariousness in bonobos. While bonobo females exhibited a slightly higher average number of females in their parties, there is neither a species difference in the time females spent alone, nor in the number of female party members in the absence of sexually attractive females. We find that the more frequent presence of maximally tumescent females in bonobos is associated with a significantly stronger increase in the number of female party members, independent of variation in a behavioural proxy for food abundance. This indicates the need to look beyond ecology when explaining species differences in female sociality as it refutes the idea that the higher gregariousness among bonobo females is driven by ecological factors alone and highlights that the temporal distribution of female sexual receptivity is an important factor to consider when studying mammalian sociality.

Chaotic dynamics driven by particle-core interactions

High-intensity beams in modern linacs are frequently encircled by diffuse halos, which drive sustained particle losses and result in the gradual degradation of accelerating structures. In large part, the growth of halos is facilitated by internal space-charge forces within the beams, and detailed characterization of this process constitutes an active area of ongoing research. A partial understanding of dynamics that ensue within space-charge dominated beams is presented by the particle-core interaction paradigm—a mathematical model wherein single particle dynamics, subject to the collective potential of the core, is treated as a proxy for the broader behavior of the beam. In this work, we investigate the conditions for the onset of large-scale chaos within the framework of this model and demonstrate that the propensity toward stochastic evolution is strongly dependent upon the charge distribution of the beam. In particular, we show that while particle motion within a uniformly charged beam is dominantly regular, rapid deterministic chaos readily arises within space-charge dominated Gaussian beams. Importantly, we find that for sufficiently high values of the beam's space charge and beam pulsation amplitude, enhanced chaotic mixing between the core and the halo can lead to an enhanced radial diffusion of charged particles. We explain our results from analytic grounds by demonstrating that chaotic motion is driven by the intersection of two principal resonances of the system and derives the relevant overlap conditions. Additionally, our analysis illuminates a close connection between the mathematical formulation of the particle-core interaction model and the Andoyer family of integrable Hamiltonians.

Collective attention in navigating homing pigeons: group size effect and individual differences

One prominent feature of collective attention is the so-called ‘group size effect’. Often documented in studies of vigilance by animals foraging gregariously, this effect describes how individual group members are able to reduce their attention to environmental cues (e.g. predators) as group size increases, since the group can pool information from multiple individuals. Despite extensive literature in one context (foraging–vigilance), it remains unclear whether this effect can be observed in other contexts where animals face different informational demands (e.g. navigation). Using a custom-made sensor combining head-mounted inertial measurement unit and back-mounted GPS, we examined head movement, a proxy for visual scanning behaviour, in homing pigeons, Columba livia , flying alone, in pairs and in flocks (ca. 10 individuals). Individual birds' head movements decreased sharply when they switched from solo to paired flights and again when they switched from paired to flock flights. Homing efficiency (or route straightness) did not decrease in parallel with decreasing head movement but continued to increase over repeated flights. We also found systematic individual differences during flock homing flights, where birds positioned more frontally and more centrally in the flock made larger head movements. Moreover, leaders were positioned more frontally and tended to show larger head movements than followers. Decreased head movement by peripheral birds suggested increased attention to the rest of the flock rather than increased individual vigilance (contra ‘the edge effect’). Overall, our results suggest that individual birds reduced their visual scanning during navigation because of the need to attend closely to fellow flock members to maintain flock cohesion. While reduced per capita visual scanning may reduce the amount of environmental information available to individual birds, it is likely to be compensated by the flock's collective attention. • The group size effect in attention was examined in the context of navigation. • We measured head movement of homing pigeons using a custom-made sensor. • Pigeons flew alone, in pairs, and in flocks (∼10 individuals). • Pigeons decreased their head movement sharply as the flock size increased. • This effect was likely driven by individuals' efforts to maintain flock cohesion.

Hippocampal subfield volumes and memory discrimination in the developing brain

The ability to keep distinct memories of similar events is underpinned by a type of neural computation called pattern separation (PS). Children typically report coarse-grained memories narratives lacking specificity and detail. This lack of memory specificity is illustrative of an immature or impaired PS. Despite its importance for the ontogeny of memory, data regarding the maturation of PS during childhood is still scarce. PS is known to rely on the hippocampus, particularly on hippocampal subfields DG and CA3. In this study, we used a memory discrimination task, a behavioral proxy for PS, and manually segmented hippocampal subfields volumes in the hippocampal body in a cohort of 26 children aged from 5 to 12 years. We examined the association between subfields volumes and memory discrimination performance. The main results were: (1) we showed age-related differences of memory discrimination suggesting a continuous increase of memory performance during early to late childhood. (2) We evidenced distinct associations between age and the volumes of hippocampal subfield, suggesting distinct developmental trajectories. (3) We showed a relationship between memory discrimination performance and the volumes of CA3 and subiculum. Our results further confirm the role of CA3 in memory discrimination, and suggest to scrutinize more closely the role of the subiculum. Overall, we showed that hippocampal subfields contribute distinctively to PS during development.

Mondrian conformal anomaly detection for fault sequence identification in heterogeneous fleets

We considered the case of monitoring a large fleet where heterogeneity in the operational behavior among its constituent units (i.e., systems or machines) is non-negligible, and no labeled data is available. Each unit in the fleet, referred to as a target, is tracked by its sub-fleet. A conformal sub-fleet (CSF) is a set of units that act as a proxy for the normal operational behavior of a target unit by relying on the Mondrian conformal anomaly detection framework. Two approaches, the k-nearest neighbors and conformal clustering, were investigated for constructing such a sub-fleet by formulating a stability criterion. Moreover, it is important to discover the sub-sequence of events that describes an anomalous behavior in a target unit. Hence, we proposed to extract such sub-sequences for further investigation without pre-specifying their length. We refer to it as a conformal anomaly sequence (CAS). Furthermore, different nonconformity measures were evaluated for their efficiency, i.e., their ability to detect anomalous behavior in a target unit, based on the length of the observed CAS and the S-criterion value. The CSF approach was evaluated in the context of monitoring district heating substations. Anomalous behavior sub-sequences were corroborated with the domain expert leading to the conclusion that the proposed approach has the potential to be useful for both diagnostic and knowledge extraction purposes, especially in domains where labeled data is not available or hard to obtain.

A Slight Increase in Reverberation Time in the Classroom Affects Performance and Behavioral Listening Effort.

The purpose of this study was to investigate the effect of a small change in reverberation time (from 0.57 to 0.69 s) in a classroom on children's performance and listening effort. Aiming for ecological listening conditions, the change in reverberation time was combined with the presence or absence of classroom noise. In three academic tasks, the study examined whether the effect of reverberation was modulated by the presence of noise and depended on the children's age. A total of 302 children (aged 11-13 years, grades 6-8) with normal hearing participated in the study. Three typical tasks of daily classroom activities (speech perception, sentence comprehension, and mental calculation) were administered to groups of children in two listening conditions (quiet and classroom noise). The experiment was conducted inside real classrooms, where reverberation time was controlled. The outcomes considered were task accuracy and response times (RTs), the latter taken as a behavioral proxy for listening effort. Participants were also assessed on reading comprehension and math fluency. To investigate the impact of noise and/or reverberation, these two scores were entered in the statistical model to control for individual child's general academic abilities. While the longer reverberation time did not significantly affect accuracy or RTs under the quiet condition, it had several effects when in combination with classroom noise, depending on the task measured. A significant drop in accuracy with a longer reverberation time emerged for the speech perception task, but only for the grade 6 children. The effect on accuracy of a longer reverberation time was nonsignificant for sentence comprehension (always at ceiling), and depended on the children's age in the mental calculation task. RTs were longer for moderate than for short reverberation times in the speech perception and sentence comprehension tasks, while there was no significant effect of the different reverberation times on RTs in the mental calculation task. The results indicate small, but statistically significant, effects of a small change in reverberation time on listening effort as well as accuracy for children aged 11 to 13 performing typical tasks of daily classroom activities. Thus, the results extend previous findings in adults to children as well. The findings also contribute to a better understanding of the practical implications and importance of optimal ranges of reverberation time in classrooms. A comparison with previous studies underscored the importance of early reflections as well as reverberation times in classrooms.

Family characteristics of female-headed households in Pakistan in the context of health promotion.

Objective of this project is to describe characteristics of Pakistani women household heads and investigate effect differences with men in the context of health behavior. We used 2012 - 13 Pakistan Demographic and Health Survey data to conduct secondary data analysis of 10868 households. In this article, methods that we described household head and household characteristics, and polio vaccination compliance as a proxy for health behavior. Univariate analysis was conducted to assess the relationship of household head gender with household characteristics and health behavior, first for the whole sample and then for currently married household heads. Significant relationships were entered in two multivariate logistic models. Results show that all demographic covariates were statistically significant (p < 0.05) except employment status. Adjusted associations were significant for age, marital status, wealth and ethnicity (p < 0.05). Polio compliance score was significantly higher for households headed by currently married men compared with currently married women, when adjusted for covariates and concluded certain household and head characteristic associations with gender suggest a greater likelihood of female-headed households, while male-headed households were associated with better polio vaccine compliance. Further research is needed with more complex health behavior composites to assess any relationship between gender and health behavior.

Measurement of Shared Social Identity in Singing Groups for People With Aphasia.

Community groups are commonly used as a mode of delivery of interventions for promoting health and well-being. Research has demonstrated that developing a sense of shared social identity with other group members is a key mechanism through which the health benefits of group membership are realized. However, there is little understanding of how shared social identity emerges within these therapeutic settings. Understanding the emergence of shared social identity may help researchers optimize interventions and improve health outcomes. Group-based singing activities encourage coordination and a shared experience, and are a potential platform for the development of shared social identity. We use the “Singing for People with Aphasia” (SPA) group intervention to explore whether group cohesiveness, as a behavioral proxy for shared social identity, can be observed and tracked across the intervention. Video recordings of group sessions from three separate programmes were rated according to the degree of cohesiveness exhibited by the group. For all treatment groups, the final group session evidenced reliably higher levels of cohesiveness than the first session (t values ranged from 4.27 to 7.07; all p values < 0.003). As well as providing confidence in the design and fidelity of this group-based singing intervention in terms of its capacity to build shared social identity, this evaluation highlighted the value of observational methods for the analysis of shared social identity in the context of group-based singing interventions.

Inexperienced but still interested – Indoor-only cats are more inclined for predatory play than cats with outdoor access

Many companion cats (Felis catus) in industrialised countries are raised under human supervision and often kept completely indoors. Even if we assume that cats were not selected intentionally against hunting behaviour, we can still hypothesize that because of the differences in their epigeny and prey-related experiences, adult cats would show different willingness to engage in hunting-type behaviours. Play is considered as a useful proxy for testing predatory behaviour in cats under non-invasive conditions. We investigated the influence of raising and keeping conditions on predatory play behaviour in companion cats. We recorded the subjects’ (N = 31) reactions to artificial prey-like stimuli such as balls of different sizes (latency of approach and latency of contact), catching wand (frequency of failed attempts of catching, duration of holding) and playback sound of birds, paper crumpling, plastic bags, and mice (latency and duration of search for sound source).Indoor-only cats approached, touched or played with balls sooner than indoor-outdoor cats. Indoor-only cats started searching sooner than indoor-outdoor cats for the playback sounds. Cats raised with their mother for a longer duration, had less failed attempts in catching the chaser, than subjects that were raised with their mother for a shorter duration, irrespective of the keeping condition.Indoor-only cats were more interested in the artificial stimuli that show more or less resemblance with the prey, even though these cats have been completely deprived of experience with live prey. There are various theories that can explain these findings, including higher play drive because of the lack of stimulation; less refined prey recognition; or reduced fear due to lack of experience in the indoor-only cats.

Simulating Melting in 2D Seismic Fault Gouge

AbstractDuring an earthquake, fault slip weakening is often explained by frictional heating phenomena, generally promoting melt production on the fault surface. Here, we investigate the influence of melt production at the scale of the grains composing a fault gouge. We use a modern version of Discrete Element Modeling able to deal with realistic grain shapes in 2D, and couple it with a Multibody Meshfree Approach able to provide a satisfactory proxy for the mechanical behavior of molten grains. Frictional sliding of solid grains and viscous shearing of molten grains are monitored during simulations. Our results confirm the natural tendency of granular gouge to localize deformation in a thin layer, and thus to trigger local melt production. We also show that the appearance of melt is likely to enhance this localization, and might create a positive feedback to its own production. We propose guidelines for the future writing of a friction model including melting, inspired by these simulation results.