A new approach to geostatistical synthesis of historical records reveals capuchin spatial responses to climate and demographic change.

Recent proliferation of GPS technology has transformed animal movement research. Yet, time-series data from this recent technology rarely span beyond a decade, constraining longitudinal research. Long-term field sites hold valuable historic animal location records, including hand-drawn maps and semantic descriptions. Here, we introduce a generalised workflow for converting such records into reliable location data to estimate home ranges, using 30 years of sleep-site data from 11 white-faced capuchin (Cebus imitator) groups in Costa Rica. Our findings illustrate that historic sleep locations can reliably recover home range size and geometry. We showcase the opportunity our approach presents to resolve open questions that can only be addressed with very long-term data, examining how home ranges are affected by climate cycles and demographic change. We urge researchers to translate historical records into usable movement data before this knowledge is lost; it is essential to understanding how animals are responding to our changing world.

Male-biased stone tool use by wild white-faced capuchins (Cebus capucinus imitator).

Tool-using primates often show sex differences in both the frequency and efficiency of tool use. In species with sex-biased dispersal, such within-group variation likely shapes patterns of cultural transmission of tool-use traditions between groups. On the Panamanian islands of Jicarón and Coiba, a population of white-faced capuchins (Cebus capucinus imitator)-some of which engage in habitual stone tool use-provide an opportunity to test hypotheses about why such sex-biases arise. On Jicarón, we have only observed males engaging in stone tool use, whereas on Coiba, both sexes are known to use tools. Using 5 years of camera trap data, we provide evidence that this variation likely reflects a sex difference in tool use rather than a sampling artifact, and then test hypotheses about the factors driving this pattern. Differences in physical ability or risk-aversion, and competition over access to anvils do not account for the sex-differences in tool-use we observe. Our data show that adult females are physically capable of stone tool use: adult females on Coiba and juveniles on Jicarón smaller than adult females regularly engage in tool use. Females also have ample opportunity to use tools: the sexes are equally terrestrial, and competition over anvils is low. Finally, females rarely scrounge on left-over food items either during or after tool-using events, suggesting they are not being provisioned by males. Although it remains unclear why adult white-faced capuchin females on Jicarón do not use stone-tools, our results illustrate that such sex biases in socially learned behaviors can arise even in the absence of obvious physical, environmental, and social constraints. This suggests that a much more nuanced understanding of the differences in social structure, diet, and dispersal patterns are needed to explain why sex-biases in tool use arise in some populations but not in others.

Inferential power in identifying frequency-dependent social learning strengthened by increasing behavioural options.

Two-option choice experimental designs are the most commonly employed framework for identifying evidence of social learning or social learning strategies in captive and wild populations. In nature, however, animals often choose from more than two behaviours, and multiple innovations may arise simultaneously. Studies of animal social learning are often constrained by small sample sizes, which limit researchers' ability to convincingly identify the proposed social learning strategy responsible for behavioural choice. In this study, I examine whether expanding behavioural options from k = 2 to k > 2 and increasing sample size affects inferential power in identifying social learning strategies. I focus on three frequency-dependent learning strategies: conformist transmission, unbiased transmission and anti-conformist transmission. I simulate 100 datasets for 72 parameter combinations, yielding 7200 simulations. I evaluate number of options (k = 2, 3, 4, 5), population size (n = 5, 10, 25, 50, 100, 250) and the logarithmic strength of frequency dependence (log(f) = log(1∕3), log(1), log(3)). I then fit a Bayesian social learning model to simulated data to evaluate the percent of the posterior consistent with type of frequency dependence, posterior standard deviations, highest posterior density intervals and posterior medians relative to the true simulated value of log(f). I show that increasing the number of options an animal can choose from increases the accuracy and certainty of identifying the type and magnitude of frequency-dependent social learning. These effects are particularly pronounced at small to intermediate sample sizes, which are common in empirical studies of animal social learning. These findings suggest that knowing what an animal did not choose is equally important as knowing what an animal did choose when identifying social learning strategies. By strategically increasing the number of behaviours from which an animal can choose, researchers can increase inferential power in identifying social learning strategies without increasing sample size, that is, adding additional animals or collecting more data.

Cultural diffusion dynamics depend on behavioural production rules.

Culture is an outcome of both the acquisition of knowledge about behaviour through social transmission, and its subsequent production by individuals. Acquisition and production are often discussed or modelled interchangeably, yet to date no study has explored the consequences of their interaction for cultural diffusions. We present a generative model that integrates the two, and ask how variation in production rules might influence diffusion dynamics. Agents make behavioural choices that change as they learn from their productions. Their repertoires may also change, and the acquisition of behaviour is conditioned on its frequency. We analyse the diffusion of a novel behaviour through social networks, yielding generalizable predictions of how individual-level behavioural production rules influence population-level diffusion dynamics. We then investigate how linking acquisition and production might affect the performance of two commonly used inferential models for social learning; network-based diffusion analysis, and experience-weighted attraction models. We find that the influence that production rules have on diffusion dynamics has consequences for how inferential methods are applied to empirical data. Our model illuminates the differences between social learning and social influence, demonstrates the overlooked role of reinforcement learning in cultural diffusions, and allows for clearer discussions about social learning strategies.

Older, sociable capuchins (Cebus capucinus) invent more social behaviors, but younger monkeys innovate more in other contexts.

An important extension to our understanding of evolutionary processes has been the discovery of the roles that individual and social learning play in creating recurring phenotypes on which selection can act. Cultural change occurs chiefly through invention of new behavioral variants combined with social transmission of the novel behaviors to new practitioners. Therefore, understanding what makes some individuals more likely to innovate and/or transmit new behaviors is critical for creating realistic models of culture change. The difficulty in identifying what behaviors qualify as new in wild animal populations has inhibited researchers from understanding the characteristics of behavioral innovations and innovators. Here, we present the findings of a long-term, systematic study of innovation (10 y, 10 groups, and 234 individuals) in wild capuchin monkeys (Cebus capucinus) in Lomas Barbudal, Costa Rica. Our methodology explicitly seeks novel behaviors, requiring their absence during the first 5 y of the study to qualify as novel in the second 5 y of the study. Only about 20% of 187 innovations identified were retained in innovators' individual behavioral repertoires, and 22% were subsequently seen in other group members. Older, more social monkeys were more likely to invent new forms of social interaction, whereas younger monkeys were more likely to innovate in other behavioral domains (foraging, investigative, and self-directed behaviors). Sex and rank had little effect on innovative tendencies. Relative to apes, capuchins devote more of their innovations repertoire to investigative behaviors and social bonding behaviors and less to foraging and comfort behaviors.

Male-female relationships in olive baboons (Papio anubis): Parenting or mating effort?

Long-term male-female bonds and bi-parental investment in offspring are hallmarks of human society. A key question is how these traits evolved from the polygynandrously mating multimale multifemale society that likely characterized the Pan-Homo ancestor. In all three species of savanna baboons, lactating females form strong ties (sometimes called "friendships") with one or more adult males. For yellow baboons (Papio cynocephalus) and chacma baboons (Papio ursinus), several lines of evidence suggest that these relationships are a form of male parenting effort. In olive baboons (Papio anubis), females are thought to preferentially mate with their "friends", and male-female bonds may thus function as a form of mating effort. Here, we draw on behavioral and genetic data to evaluate the factors that shape male-female relationships in a well-studied population of olive baboons. We find support for the parenting effort hypothesis in that sires have stronger bonds with their infants' mothers than do other males. These bonds sometimes persist past weaning age and, in many cases, the sire of the previous infant is still a close partner of the female when she nurses her subsequent offspring. We find that males who have the strongest bonds with females that have resumed cycling, but are not currently sexually receptive, are more likely to sire the female's next offspring but the estimate is associated with large statistical uncertainty. We also find that in over one third of the cases, a female's successive infants were sired by the same male. Thus, in olive baboons, the development of stable breeding bonds and paternal investment seem to be grounded in the formation of close ties between males and anestrous females. However, other factors such as male dominance rank also influence paternity success and may preclude stability of these bonds to the extent found in human societies.

Pay-off-biased social learning underlies the diffusion of novel extractive foraging traditions in a wild primate.

The type and variety of learning strategies used by individuals to acquire behaviours in the wild are poorly understood, despite the presence of behavioural traditions in diverse taxa. Social learning strategies such as conformity can be broadly adaptive, but may also retard the spread of adaptive innovations. Strategies like pay-off-biased learning, by contrast, are effective at diffusing new behaviour but may perform poorly when adaptive behaviour is common. We present a field experiment in a wild primate, Cebus capucinus, that introduced a novel food item and documented the innovation and diffusion of successful extraction techniques. We develop a multilevel, Bayesian statistical analysis that allows us to quantify individual-level evidence for different social and individual learning strategies. We find that pay-off-biased and age-biased social learning are primarily responsible for the diffusion of new techniques. We find no evidence of conformity; instead rare techniques receive slightly increased attention. We also find substantial and important variation in individual learning strategies that is patterned by age, with younger individuals being more influenced by both social information and their own individual experience. The aggregate cultural dynamics in turn depend upon the variation in learning strategies and the age structure of the wild population.

Safety and Efficacy of Incretin-Based Therapies in Patients With Type 2 Diabetes Mellitus and CKD: A Systematic Review and Meta-analysis.

BACKGROUND: The pharmacokinetics and pharmacodynamics of antidiabetic therapies for patients with type 2 diabetes are often altered in the context of chronic kidney disease (CKD). STUDY DESIGN: Systematic review and meta-analysis. SETTING & POPULATION: Patients with type 2 diabetes and CKD. SELECTION CRITERIA FOR STUDIES: 2 reviewers independently screened studies identified through bibliographic databases (Cochrane Library, PubMed, Embase, International Pharmaceutical Abstracts), clinical trial registries, and references from pertinent articles and clinical practice guidelines. Eligible studies included randomized controlled trials evaluating incretin-based therapy in adults with type 2 diabetes and estimated glomerular filtration rates < 60mL/min/1.73m2. INTERVENTIONS: Incretin-based therapies (dipeptidyl peptidase 4 inhibitors and glucagon-like peptide 1 receptor agonists) compared to placebo or active antidiabetic therapies. OUTCOMES: Changes in glycated hemoglobin (HbA1c), hypoglycemia, mortality, change in fasting plasma glucose, cardiovascular events, and end-stage renal disease. RESULTS: Of 1,619 nonduplicate records screened, 13 studies were included. Compared to placebo, incretin-based therapies significantly reduced HbA1c levels (n = 9; weighted mean difference, -0.64; 95% CI, -0.79 to -0.48; I2 = 43%); however, compared with active comparators, they did not (n = 4; weighted mean difference, -0.07; 95% CI, -0.25 to 0.12; I2 = 38%). Incretin-based therapies significantly increased the risk for hypoglycemia compared to placebo (n = 7; relative risk [RR], 1.38; 95% CI, 1.01-1.89; I2 = 0%) but no effect was observed versus active comparators (n = 4; RR, 0.24; 95% CI, 0.03-1.94; I2 = 52%). Limited evidence exists for all-cause mortality (placebo: n = 7 [RR, 1.21; 95% CI, 0.64-2.29; I2 = 0%]; active comparators: n = 3 [RR, 0.70; 95% CI, 0.32-1.54; I2 = 0%]). LIMITATIONS: Variation among interventions, small number of studies, heterogeneity between studies, and high risk for attrition bias in 7 of the selected studies. CONCLUSIONS: In patients with moderate or severe CKD, incretin-based therapies are effective in reducing HbA1c levels. Hypoglycemic events are rare, and wide CIs for the association preclude any definitive conclusions. Likewise, wide CIs were observed for mortality, cardiovascular events, and end-stage renal disease.

Psychometric properties of the Patient's Perception of Life on Hemodialysis Scale.

BACKGROUND AND PURPOSE: Hemodialysis (HD) is the main form of renal replacement therapy for many patients with end-stage renal disease. The purpose of this research is to assess reliability and validity of the Patient's Perception of Hemodialysis Scale. METHODS: Using a cross-sectional design and a convenient sample (n = 236), psychometric properties of the PPHS were examined. Validity was assessed using factor analysis and Pearson's correlation. Reliability was determined using Cronbach's alpha and test-retest stability (n = 30). RESULTS: Validity and reliability was supported. CONCLUSION: Examination of the PPHS provides evidence that it is a valid and reliable instrument for measuring disease-specific concerns with the HD patients, assessing how people experience life, and identifying ways in which people interpret the meaning of their physical and psychosocial health and adaptation to life on HD.

Canadian Association of Radiologists consensus guidelines for the prevention of contrast-induced nephropathy: update 2012.

PURPOSE: Contrast-induced acute kidney injury or contrast-induced nephropathy (CIN) is a significant complication of intravascular contrast medium (CM). These guidelines are intended as a practical approach to risk stratification and prevention. The major risk factor that predicts CIN is pre-existing chronic kidney disease. METHODS: Members of the committee represent radiologists and nephrologists across Canada. The previous guidelines were reviewed, and an in-depth up-to-date literature review was carried out. RESULTS: A serum creatinine level (SCr) should be obtained, and an estimated glomerular filtration rate (eGFR) should be calculated within 6 months in the outpatient who is stable and within 1 week for inpatients and patients who are not stable. Patients with an eGFR of ≥ 60 mL/min have an extremely low risk of CIN. The risk of CIN after intra-arterial CM administration appears be at least twice that after intravenous administration. Fluid volume loading remains the single most important measure, and hydration regimens that use sodium bicarbonate or normal saline solution should be considered for all patients with GFR < 60 mL/min who receive intra-arterial contrast and when GFR < 45 mL/min in patients who receive intravenous contrast. Patients are most at risk for CIN when eGFR < 30 mL/min. Additional preventative measures include the following: avoid dehydration, avoid CM when appropriate, minimize CM volume and frequency, avoid high osmolar CM, and discontinue nephrotoxic medications 48 hours before administration of CM.

Responsiveness of the patient's perception of hemodialysis scale.

OBJECTIVES: To assess hemodialysis (HD) patients' physical health, social supports, psychosocial well-being and the interrelationship among patients' experiences, demographics, illness characteristics, and biochemical indicators of health. To determine responsiveness of the Patient's Perception of Hemodialysis Scale (PPHS) to change in health status and critical events. METHODS: Using a longitudinal design HD patients (n = 85) were assessed at two time periods. Data analysis included measures of central tendency and tests of difference to assess interrelationships and responsiveness of the PPHS. RESULTS: There were no significant changes in PPHS's subscales scores between measurement times or groups based on demographic variables. Significant differences were found in the number of co-morbid illnesses, illness severity, albumin, and urea reduction. The Psychosocial Distress subscale varied significantly in relation to time on HD, reason for admission to hospital, and number of admissions. Physical Health scores were significantly different for subgroups divided by illness, illness severity, number of illnesses, age, albumin and reason for admission. PPHS subscale mean scores were responsive to positive events in the predicted direction most of the time and appeared to have had more of an effect on the PPHS scores than negative critical events. CONCLUSION: The PPHS is responsive to a change in physical health and positive critical events, but results were unsubstantiated for patient's reaction to negative critical events. The PPHS is reliable, valid, and responsive to physical changes and positive critical events. This instrument offers health care professionals a viable method for assessing important factors capable of predicting quality outcomes.

Coupling of coastal activity with tidal cycles is stronger in tool-using capuchins (Cebus capucinus imitator).

Terrestrial mammals exploiting coastal resources must cope with the challenge that resource availability and accessibility fluctuate with tidal cycles. Tool use can improve foraging efficiency and provide access to structurally protected resources that are otherwise unavailable (e.g. molluscs and fruits). To understand how variable accessibility of valuable resources shapes behavioural patterns, and whether tool use aids in the efficient exploitation of intertidal resources, we compared the relationship between tidal cycles and activity patterns of tool-using versus non-tool-using groups of white-faced capuchin monkeys on Jicarón Island in Coiba National Park, Panama. Although tool use on Jicarón is localized to a small stretch of coast (approx. 1 km), all coastal groups forage on intertidal resources. Using more than 5 years of camera trap data at varying distances from the coast, we found that capuchins on Jicarón showed increased coastal activity during specific parts of the tidal cycle, and that this relationship differed between tool-using and non-tool-using groups, as well as between seasons. Activity patterns of tool-using capuchins were more strongly and consistently tied to tidal cycles compared with non-tool-users, indicating that tool use might allow for more efficient exploitation of tidal resources. Our findings highlight the potential of tool use to aid niche expansion.

Canadian Association of Radiologists Guidance on Contrast-Associated Acute Kidney Injury.

Purpose: Iodinated contrast media is one of the most frequently administered pharmaceuticals. In Canada, over 5.4 million computed tomography (CT) examinations were performed in 2019, of which 50% were contrast enhanced. Acute kidney injury (AKI) occurring after iodinated contrast administration was historically considered a common iatrogenic complication which was managed by screening patients, prophylactic strategies, and follow-up evaluation of renal function. The Canadian Association of Radiologists (CAR) initially published guidelines on the prevention of contrast induced nephropathy in 2007, with an update in 2012. However, new developments in the field have led to the availability of safer contrast agents and changes in clinical practice, prompting a complete revision of the earlier recommendations. Information sources: Published literature, including clinical trials, retrospective cohort series, review articles, and case reports, along with expert opinions from radiologists and nephrologists across Canada. Methods: The leadership of the CAR formed a working group of radiologists and nephrologists with expertise in contrast administration and patient management related to contrast-associated AKI. We conducted a comprehensive review of the published literature to evaluate the evidence about contrast as a cause of AKI, and to inform evidence-based recommendations. Based on the available literature, the working group developed consensus recommendations. Key Findings: The working group developed 21 recommendations, on screening, choice of iodinated contrast media, prophylaxis, medication considerations, and post contrast administration management. The key changes from the 2012 guidelines were (1) Simplification of screening to a simple questionnaire, and not delaying emergent examinations due to a need for creatinine measurements (2) Prophylaxis considerations only for patients with estimated glomerular filtration rate (eGFR) less than 30 mL/min/1.73 m2 (3) Not recommending the routine discontinuation of any drugs to decrease risk of AKI, except metformin when eGFR is less than 30 mL/min/1.73 m2 and (4) Not requiring routine follow up serum creatinine measurements post iodinated contrast administration. Limitations: We did not conduct a formal systematic review or meta-analysis. We did not evaluate our specific suggestions in the clinical environment. Implications: Given the importance of iodinated contrast media use in diagnosis and management, and the low risk of AKI after contrast use, these guidelines aim to streamline the processes around iodinated contrast use in most clinical settings. As newer evidence arises that may change or add to the recommendations provided, the working group will revise these guidelines.

Justification: Les agents de contraste iodés (ACI) sont parmi les produits pharmaceutiques les plus fréquemment administrés. Au Canada, plus de 5,4 millions d'examens de tomodensitométrie (TDM) ont été réalisés en 2019, dont 50 % ont été faits avec un ACI. L'insuffisance rénale aiguë (IRA) survenant après l'administration d'un ACI était historiquement considérée comme une complication iatrogénique fréquente qui était prise en charge par le dépistage des patients, des stratégies prophylactiques et une évaluation de suivi de la fonction rénale. L'Association canadienne des radiologistes (CAR) a publié des lignes directrices pour la prévention de la néphropathie induite par les agents de contraste en 2007 et une mise à jour en 2012. De nouveaux développements sur le terrain ont toutefois mené à la disponibilité d'agents de contraste plus sécuritaires et à des changements dans la pratique clinique, ce qui a entraîné une révision complète des recommandations antérieures. Sources: La littérature publiée, y compris les essais cliniques, les séries de cohortes rétrospectives, les articles-synthèse et les rapports de cas, de même que les opinions d'experts de radiologistes et de néphrologues de partout au Canada. Méthodologie: La direction de la CAR a formé un groupe de travail composé de radiologues et de néphrologues ayant une expertise dans l'administration d'ACI et la gestion de patients atteints d'IRA survenant après l'administration d'un ACI. Le groupe a procédé à une revue complète de la littérature publiée afin d'évaluer les données probantes sur les ACI comme cause de l'IRA et de formuler des recommandations en fonction de celles-ci. Le groupe de travail a élaboré des recommandations consensuelles en se fondant sur la documentation disponible. Principaux résultats: Le groupe de travail a élaboré 21 recommandations sur le dépistage, le choix des agents de contraste iodés, la prophylaxie, les considérations relatives aux médicaments et la gestion post-administration de l'ACI. Les principaux changements par rapport aux lignes directrices de 2012 étaient : (1) de simplifier le dépistage à un simple questionnaire et de ne pas retarder les examens émergents en raison du besoin de mesurer la créatinine; (2) d'avoir des considérations prophylactiques uniquement pour les patients dont le débit de filtration glomérulaire estimé (DFGe) est inférieur à 30 mL/min/1,73 m2; (3) de ne pas recommander l'arrêt des médicaments visant à réduire le risque d'IRA, comme c'est normalement le cas, sauf la metformine lorsque le DFGe est inférieur à 30 mL/min/1,73 m2 et; (4) ne pas demander de mesures de suivi de routine de la créatinine sérique après administration d'un agent de contraste iodé. Limites: Le groupe n'a pas procédé à une revue formelle et systématique de la littérature sur le sujet ni à une méta-analyse. Les suggestions n'ont pas été évaluées dans un environnement clinique. Conclusion: Compte tenu de l'importance des agents de contraste iodés dans le diagnostic et la prise en charge des patients, et du faible risque d'IRA encouru après leur administration, ces recommandations ne visent qu'à simplifier les processus relatifs à l'utilisation des ACI dans la plupart des milieux cliniques. Le groupe de travail révisera ces lignes directrices au fur et à mesure que des éléments de preuve plus récents seront ajoutés aux recommandations fournies.

Randomized Controlled Trials 5: Biomarkers and Surrogates/Outcomes.

Biomarkers are characteristics that are measured as indicators of normal biological processes, pathogenic processes, or responses to an exposure or intervention, including therapeutic interventions. Biomarkers may serve a number of important uses, particularly in diagnosis and prognosis of disease, and as surrogates for clinical outcomes of disease (i.e., outcomes that measure how patient survives, functions, or feels). Establishing the validity of a given biomarker for a specific role requires the conduct of carefully designed clinical studies in which the biomarker and the outcome of interest are measured independently. The design and analysis of such studies is discussed. Surrogate outcomes in clinical trials consist of events or biomarkers intended to reflect important clinical outcomes. Surrogate outcomes may offer advantages in providing statistically robust estimates of treatment effects with smaller sample sizes. However, to be useful, surrogate outcomes have to be validated to ensure that the effect of therapy on them truly reflects the effect of therapy on the important clinical outcomes of interest.

Longitudinal Studies 2: Modeling Data Using Multivariate Analysis.

Statistical models are used to study the relationship between exposure and disease while accounting for the potential role of other factors' impact upon outcomes. This adjustment is useful to obtain unbiased estimates of true effects or to predict future outcomes. Statistical models include a systematic and an error component. The systematic component explains the variability of the response variable as a function of the predictors and is summarized in the effect estimates (model coefficients). The error element of the model represents the variability in the data unexplained by the model and is used to build measures of precisions around the point estimates (Confidence Intervals).

Longitudinal Studies 3: Data Modeling Using Standard Regression Models and Extensions.

In longitudinal studies, the relationship between exposure and disease can be measured once or multiple times while participants are monitored over time. Traditional regression techniques are used to model outcome data when each epidemiological unit is observed once. These models include generalized linear models for quantitative continuous, discrete, or qualitative outcome responses, and models for time-to-event data. When data come from the same subjects or group of subjects, observations are not independent and the underlying correlation needs to be addressed in the analysis. In these circumstances, extended models are necessary to handle complexities related to clustered data, and repeated measurements of time-varying predictors and/or outcomes.

Evaluation of Diagnostic Tests.

As technology advances, diagnostic tests continue to improve and each year, we are presented with new alternatives to standard procedures. Given the plethora of diagnostic alternatives, diagnostic tests must be evaluated to determine their place in the diagnostic armamentarium. The first step involves determining the accuracy of the test, including the sensitivity and specificity, positive and negative predictive values, likelihood ratios for positive and negative tests, and receiver operating characteristic (ROC) curves. The role of the test in a diagnostic pathway has then to be determined, following which the effect on patient outcome should be examined.

Randomized Controlled Trials 1: Design.

Today's clinical practice relies on the application of well-designed clinical research, the gold standard test of an intervention being the randomized controlled trial. Principles of the randomized control trial include emphasis on the principal research question, randomization, blinding; definitions of outcome measures, of inclusion and exclusion criteria, and of co-morbid and confounding factors; enrolling an adequate sample size; planning data management and analysis; preventing challenges to trial integrity such as drop-out, drop-in, and bias. The application of pre-trial planning is stressed to ensure the proper application of epidemiological principles resulting in clinical studies that are feasible and generalizable. In addition, funding strategies and trial team composition are discussed.

Processing of novel food reveals payoff and rank-biased social learning in a wild primate.

Social learning-learning from others-is the basis for behavioural traditions. Different social learning strategies (SLS), where individuals biasedly learn behaviours based on their content or who demonstrates them, may increase an individual's fitness and generate behavioural traditions. While SLS have been mostly studied in isolation, their interaction and the interplay between individual and social learning is less understood. We performed a field-based open diffusion experiment in a wild primate. We provided two groups of vervet monkeys with a novel food, unshelled peanuts, and documented how three different peanut opening techniques spread within the groups. We analysed data using hierarchical Bayesian dynamic learning models that explore the integration of multiple SLS with individual learning. We (1) report evidence of social learning compared to strictly individual learning, (2) show that vervets preferentially socially learn the technique that yields the highest observed payoff and (3) also bias attention toward individuals of higher rank. This shows that behavioural preferences can arise when individuals integrate social information about the efficiency of a behaviour alongside cues related to the rank of a demonstrator. When these preferences converge to the same behaviour in a group, they may result in stable behavioural traditions.

Predictors of perceived health care quality for registered nurses during and after health care reform.

BACKGROUND: Limited research has focused on the predictive nature of organizational culture and trust on registered nurses' perceived health care quality in reformed health care systems. PURPOSES: The purpose of this article was to investigate nurses' perceptions of organizational culture factors, trust in employer, and perceived health care quality during and 5 years after major organizational reform in the acute care setting and to test a model linking culture to perceived health care quality. METHODOLOGY: Survey data collected from two samples of nurses (N = 222,343) during and 5 years after major organizational reform in the acute care setting of one Canadian province were analyzed, and an exploratory model linking aspects of culture, trust, and quality was tested. FINDINGS: For both periods, most variable scores were in the low range and depicted moderately positive intercorrelations with each other. Support for the proposed model was mixed. Select culture variables predicted health care quality at both periods, but trust emerged as a significant predictor in 2000 only. The findings support the negative impact of system transformation on nurses and the link between culture and health care quality. PRACTICE IMPLICATIONS: The study findings suggest that managers and policy makers must develop and implement supportive and nurturing strategies that will enhance the organizational culture (emotional climate, collaborative relations), which should result in more positive perceptions of health care quality. However, further research is required to gain a better understanding of the relationships among trust, organizational culture, and perceptions of health care quality and what implications this may or may not have for nursing practice.