Co-evolution of learning complexity and social foraging strategies

Variation in learning abilities within populations suggests that complex learning may not necessarily be more adaptive than simple learning. Yet, the high cost of complex learning cannot fully explain this variation without some understanding of why complex learning is too costly for some individuals but not for others. Here we propose that different social foraging strategies can favor different learning strategies (that learn the environment with high or low resolution), thereby maintaining variable learning abilities within populations. Using a genetic algorithm in an agent-based evolutionary simulation of a social foraging game (the producer-scrounger game) we demonstrate how an association evolves between a strategy based on independent search for food (playing a producer) and a complex (high resolution) learning rule, while a strategy that combines independent search and following others (playing a scrounger) evolves an association with a simple (low resolution) learning rule. The reason for these associations is that for complex learning to have an advantage, a large number of learning steps, normally not achieved by scroungers, are necessary. These results offer a general explanation for persistent variation in cognitive abilities that is based on co-evolution of learning rules and social foraging strategies.     

Knowledge,attitudes and determinants of exclusive breastfeeding practice among Ghanaian rural lactating mothers

Background

The practice of exclusive breastfeeding (EBF) is influenced by maternal knowledge and attitudes as well as socio-demographic and cultural factors. This study assessed knowledge, attitudes and practice of EBF among rural lactating mothers with infants aged 0–6 months. Factors associated to the practice of EBF were also investigated.

Methods

This cross-sectional study was conducted among 190 rural lactating mothers with infants aged 0–6 months seeking postnatal care at a health centre in Ghana. All data was collected using a questionnaire that contained both closed and open ended questions.

Results

About 26 % (n?=?50) of the mothers were unable to correctly define EBF. The majority (92.6 %, n?=?176) of the mothers said they felt good to EBF for 6 months, to breastfed on demand (99.5 %, n?=?189) and did not have difficulties EBF (90 %, n?=?171). Despite the generally positive attitude towards EBF, 42 % (n?=?79) of the mothers did not EBF their babies. These mothers did not practice EBF because they misunderstood certain signs of the child to mean wanting to eat food or drink water, regarded breastmilk to be inadequate to meet the nutritional needs of the child and misunderstood healthcare professionals’ EBF advice. Higher maternal education was associated with higher likelihood of EBF (OR 3.5; 95 % CI 1.6, 7.7; p?=?0.002). Mothers whose babies were younger than 3 months were more likely to EBF (OR 12.0; 95 % CI 4.4, 32.5; p?<?0.001) than those having babies aged?≥?3 months. Furthermore, higher knowledge of EBF was associated with the likelihood of EBF (OR 5.9; 95 % CI 2.6, 13.3; p?<?0.001).

Conclusion

Mothers’ knowledge and attitudes towards EBF were favourable but practice of EBF was suboptimal. This study adds additional evidence that knowledge of EBF, child’s age and maternal level of education are important determinants of the practice of EBF. Beyond dissemination of health messages, healthcare professionals should pay more counselling attention to less educated mothers, and also older children’s caregivers.

     

Perceived social support from strength and conditioning coaches among injured student athletes

Injuries suffered by student athletes not only affect their physical ability to perform in sport but also have psychological effects as well. The purpose of this study was to examine student athletes' perceptions, expectations, and satisfaction of the social support provided by their strength and conditioning coach (SC) during the later reconditioning stage of their rehabilitation and their views on the overall level of importance of each type of social support. One hundred and sixty-five participants aged 20.21 ± 1.32 years from 6 Division I Universities in the Midwest region of the USA completed the modified Social Support Survey. The results of a chi-square test assessing the responses for 6 types of social support provided by SCs based on athletes' age, gender, and sport revealed a significant difference (χ2[13,105] = 26.46, p = 0.015) for listening support differing by sport. A significant difference (χ2[13,105] = 267.74, p = 0.010) was also revealed for reported emotional challenge by sport. Results showed that the SC had a significant psychosocial impact on student-athletes' overall psychological well-being during reconditioning. This study provides evidence of the vital psychosocial role that SCs can play during an injured student-athlete's reconditioning program.     

Prevalence of exclusive breastfeeding and associated factors among mothers in rural Bangladesh: a cross-sectional study

Background

Exclusive breastfeeding (EBF) means that the infant receives only breast milk for the first six months of life after birth. In Bangladesh, the prevalence of EBF remained largely unchanged for nearly two decades and was 43% in 2007. However, in 2011, a prevalence of 64% was reported, an increase by 21 percentage points. The reasons for this large change remain speculative at this point. Thus to investigate the issue further, this study was conducted. The objective was to assess the prevalence of EBF and associated factors among mothers having children aged 0–6 months in rural Bangladesh.

Methods

A cross-sectional study was conducted in Mirzapur Upazilla (sub district) among 121 mothers of infants aged 0–6 months. Eligible mothers were identified and randomly selected using the demographic surveillance system’s computerized database that is updated weekly. A semi-structured questionnaire was used for interviews that inquired information on socio-demographic characteristics, obstetric, health service, breastfeeding related factors (initiation of breastfeeding, prelacteal feeding and colostrum feeding) and economic factors. EBF prevalence was calculated using 24 hour recall method. In multivariate analysis, a logistic regression model was developed using stepwise modeling to analyze the factors associated with EBF.

Results

The prevalence of EBF in the last 24 hours preceding the survey was 36%. Bivariate and multivariate analysis revealed no significant association between EBF and its possible predictors at 0.05 level of alpha. However, there was some evidence of an association between EBF and having a caesarean delivery (OR?=?0.47, 95% CI: 0.21, 1.06). In multivariate analysis, type of delivery: caesarean (AOR?=?0.45, 95% CI: 0.19, 1.03) and wealth quintile: richer (AOR?=?2.40, 95% CI: 0.94, 6.16) also showed some evidence of an association with EBF.

Conclusion

The prevalence of EBF in Mirzapur (36%) is lower than the national figure (64%). Prelacteal feeding was not uncommon. These findings suggest that there is a need for breastfeeding support provided by health services. Hence, promotion of EBF during the first six months of life needs to be addressed and future breastfeeding promotion programmes should give special attention to those women who are not practicing EBF.

     

Factors associated with early initiation of breastfeeding among Nepalese mothers: further analysis of Nepal Demographic and Health Survey, 2011

Background

Timely initiation of breastfeeding has been reported to reduce neonatal mortality by 19.1%. The World Health Organisation recommends early initiation of breastfeeding i.e. breastfeeding a newborn within the first hour of life. Knowledge on the rate and the determinants of early initiation of breastfeeding may help health program managers to design and implement effective breastfeeding promotion programs. The aim of this study was to determine the rate and the determinants of early initiation of breastfeeding in Nepal.

Methods

This study used the data from Nepal Demographic and Health Survey (NDHS) 2011 which is a nationally representative sample study. Chi square test and multiple logistic regression analysis were used to examine the factors associated with early initiation of breastfeeding (within one hour of birth).

Results

Of 4079 mothers, 66.4% initiated breastfeeding within one hour of delivery. Mothers with higher education (Odds Ratio (OR) 2.56; 95% CI : 1.26, 5.21), mothers of disadvantaged Janjati ethnicity (OR 1.43; 95% CI : 1.04, 1.94), mothers who were involved in agriculture occupation (OR 1.51; 95% CI : 1.16, 1.97), mothers who delivered in a health facility (OR 1.67; 95% CI : 1.25, 2.23), whose children were large at birth (OR 1.46; 95% CI : 1.07, 1.99) were more likely to initiate breastfeeding within the first hour of child birth.

Conclusions

Results suggest that two thirds of children in Nepal were breastfed within the first hour after birth. Although there was a higher prevalence of early initiation of breastfeeding among mothers who delivered in health facilities compared to mothers who delivered at home, universal practice of early initiation of breastfeeding should be a routine practice. The findings suggest the need of breastfeeding promotion programs among the mothers who are less educated, and not working. Such breastfeeding promotion programmes could be implemented via Nepal’s extensive network of community-based workers.

     

Neighborhood influences on perceived social support among parents: findings from the project on human development in Chicago neighborhoods

Background

Social support is frequently linked to positive parenting behavior. Similarly, studies increasingly show a link between neighborhood residential environment and positive parenting behavior. However, less is known about how the residential environment influences parental social support. To address this gap, we examine the relationship between neighborhood concentrated disadvantage and collective efficacy and the level and change in parental caregiver perceptions of non-familial social support.

Methodology/Principal Findings

The data for this study came from three data sources, the Project on Human Development in Chicago Neighborhoods (PHDCN) Study''s Longitudinal Cohort Survey of caregivers and their offspring, a Community Survey of adult residents in these same neighborhoods and the 1990 Census. Social support is measured at Wave 1 and Wave 3 and neighborhood characteristics are measured at Wave 1. Multilevel linear regression models are fit. The results show that neighborhood collective efficacy is a significant (ß = .04; SE = .02; p = .03), predictor of the positive change in perceived social support over a 7 year period, however, not of the level of social support, adjusting for key compositional variables and neighborhood concentrated disadvantage. In contrast concentrated neighborhood disadvantage is not a significant predictor of either the level or change in social support.

Conclusion

Our finding suggests that neighborhood collective efficacy may be important for inducing the perception of support from friends in parental caregivers over time.     

The effect of social support and the work environment upon burnout among nurses

Burnout among hospital-based nurses appears to be a serious problem affecting the delivery of health care. Findings from previous empirical research indicate that burnout among these nurses results from reactions to adversities inherent in the hospital work environment, and that burnout can lead nurses to change jobs and/or abandon the practice of nursing. This paper presents and discusses research findings on the effects of various aspects of the hospital work environment on burnout among nurses, and, in addition, evaluates the effects of social support in reducing and/or mitigating the relationship between negative aspects of the work environment and burnout. A multiple regression approach is employed to test the hypothesized model. The data were collected from a sample of nurses (n = 310) employed at Fitzsimons Army Medical Center (FAMC), Aurora, Colorado. The major determinants of burnout were found to be low job enhancement (autonomy, task orientation, clarity, innovation, and physical comfort); work pressure; and lack of supervisor support, along with the interaction term involving the combined effects of job enhancement and supervisor support. These predictors, in conjunction with demographic and job-related variables explained 53% of the variance in emotional exhaustion, a central component of the burnout syndrome.     

How copying affects the amount, evenness and persistence of cultural knowledge: insights from the social learning strategies tournament

Darwinian processes should favour those individuals that deploy the most effective strategies for acquiring information about their environment. We organized a computer-based tournament to investigate which learning strategies would perform well in a changing environment. The most successful strategies relied almost exclusively on social learning (here, learning a behaviour performed by another individual) rather than asocial learning, even when environments were changing rapidly; moreover, successful strategies focused learning effort on periods of environmental change. Here, we use data from tournament simulations to examine how these strategies might affect cultural evolution, as reflected in the amount of culture (i.e. number of cultural traits) in the population, the distribution of cultural traits across individuals, and their persistence through time. We found that high levels of social learning are associated with a larger amount of more persistent knowledge, but a smaller amount of less persistent expressed behaviour, as well as more uneven distributions of behaviour, as individuals concentrated on exploiting a smaller subset of behaviour patterns. Increased rates of environmental change generated increases in the amount and evenness of behaviour. These observations suggest that copying confers on cultural populations an adaptive plasticity, allowing them to respond to changing environments rapidly by drawing on a wider knowledge base.     

The effect of baby friendly hospital initiative and postnatal support on breastfeeding rates--Croatian experience

The effects of implementation WHO/UNICEF Breastfeeding Hospital Initiative (BFHI) and community postnatal support on breastfeeding rates were examined during and after the breastfeeding promotion campaign in one county of Croatia. Comparison with a control group indicated increase of breastfeeding prevalence in a period of BFHI implementation (1994-1998) - 68% vs. 87% at infant age 1 mo., 30% vs. 54% at 3 mo., 11.5% vs. 28% at 6 mo., and 2% vs. 3.5% at infant age 11-12 mo. (chi-square test, p < 0.05). More considerable increase has been noticed in period 1999-2000 which is characterized by breastfeeding support groups activity: 68% vs. 87% at infant age 1 mo., 30% vs. 66% at 3 mo., 11.5% vs. 49% at 6 mo., and 2% vs. 23% at infant age 11-12 mo. (chi-square test, p < 0.05). Our conclusion is that activities aiming to promote breastfeeding in maternity hospitals have had limited success. They have resulted in satisfactory increase of breastfeeding prevalence in early infant's period, but for far-reaching effect postnatal support is also required.     

Infant feeding practices and maternal socio-demographic factors that influence practice of exclusive breastfeeding among mothers in Nnewi South-East Nigeria: a cross-sectional and analytical study

Background

Malnutrition is an underlying factor in more than 50% of the major cause of infant mortality-Pneumonia, diarrhoeal disease and measles which account for 70% of infant mortality. Therefore, programs to promote adequate nutrition for age can help reduce mortality from these disease conditions and indispensible to achievement of MDG 4.

Aim

To describe the feeding practices of infants below six months of age and determine maternal socio-demographic factors that influences the practice of exclusive breastfeeding (EBF) among mothers in Nnewi, south-east Nigeria.

Methods

Four hundred mother-infant pairs attending the infant welfare clinic of the Nnamdi Azikiwe University teaching hospital (NAUTH) during 2012 were consecutively recruited after meeting the study inclusion criteria. Data on breastfeeding were based on infant feeding practice in the previous 24 hours. Exclusive breastfeeding was defined as infant feeding with only breast milk.

Results

Awareness (95.3%) and knowledge (82.0%) of EBF was high among surveyed mother but the practice of EBF (33.5%) was very low. Positive attitude towards EBF practice was shown by many (71.0%) of surveyed mothers. EBF practice decreased with increasing infant age, OR 0.72 (95% CI 0.34, 1.51) for 1–2 months, OR 0.58 (95% CI 0.23, 1.44) for 3–4 months and OR 0.20 (95% CI 0.06, 0.73) for 5–6 months compared to infants?<?1 month old. Maternal education, socioeconomic class, mode of delivery and infants first feed were retained as important maternal predictors of EBF practice after adjustment for confounders. Decreased likelihood of EBF practice was found among mothers of lower educational attainment, OR 0.33 (95% CI 0.13, 0.81), mothers who delivered through caesarean section, OR 0.38 (95% CI 0.18, 0.84), mothers of higher socio-economic status [(middle class, OR 0.46 (95% CI 0.22, 0.99) and upper class, OR 0.32 (95% CI 0.14, 0.74)] while increased likelihood of EBF practice was seen in mothers who gave their infants breast milk as their first feed, OR 3.36 (95% CI 1.75, 6.66).

Conclusion

Knowledge and awareness does not translate to practice of EBF. More effort by health workers and policy makers should be directed to mothers along the fault lines to encourage the practice of EBF.

     

Relative contributions of maternal social and biological characteristics to birth weight and gestation among mothers of different childhood socioeconomic status

Abstract

There has been no reported systematic attempt to quantify the relative unique contribution of multiple social and biologic maternal characteristics to birth weight and gestational time among mothers of differing childhood socioeconomic backgrounds. We examined this issue in three nativity cohorts from a population of 766 black prenatal clinic patients in New York City using a series of stepwise hierarchical multiple regression analyses. Different variable sets contributed to birth weight variance in each group, although total variance explained was similar for the three. Since the foreign‐born cohort represented a different higher childhood socioeconomic background, but was similar to the other groups in current SES, the differing observed associations of variable sets to birth weight may be related to childhood socioeconomic status. In all groups, social factors show more effect on gestation among births more than 2,500 grams than for smaller babies and thus account for more total explained birth weight variance for births over 2,500 grams.     

Relative contributions of maternal social and biological characteristics to birth weight and gestation among mothers of different childhood socioeconomic status

There has been no reported systematic attempt to quantify the relative unique contribution of multiple social and biologic maternal characteristics to birthweight and gestational time among mothers of differing childhood socioeconomic backgrounds. This issue was examined in 3 nativity cohorts from a population of 766 black prenatal clinic patients in New York City using a series of stepwise hierarchical multiple regression analyses. Different variable sets contributed to birthweight variance in each group, although total variance explained was similar for the 3. Since the foreign-born cohort represented a different higher childhood socioeconomic background, but was similar to the other groups in current socioeconomic status, the differing observed associations of variable sets to birthweight may be related to childhood socioeconomic status. In all groups, social factors show more effect on gestation among those births more than 2500 grams than for smaller babies and thus account for more total explained birthweight variance for births over 2500 grams. Future research is necessary to replicate these results in the general population since this is the 1st study using multivariate techniques to look at social and biological factors associated with birthweight in groups with different childhood social backgrounds.     

The effects of demonstrator social status and prior foraging success on social learning in laying hens

Opportunities for social learning within a group of animals are likely to be influenced by the social dynamics of that group. Some individuals may be more influential demonstrators than others even when there are no differences in their skill level or performance. In this study of domestic hens, Gallus gallus domesticus, differences in demonstrator salience were examined. From 24 separate flocks we selected as demonstrators a dominant cockerel, a dominant hen, a mid-ranking hen or a subordinate hen. Demonstrators were pretrained to perform an operant discrimination task to obtain food. Six observers from each flock individually watched the demonstrator perform the task for four 5-min sessions held on consecutive days. On the fifth day observers were tested individually in the operant chamber. We analysed data from 19 flocks, where there were no quantitative differences in demonstrator performance. Observer hens of relatively high social status performed more correct operant pecks than observer hens of relatively low social status. Demonstrator category also had a significant effect on subsequent observer behaviour. Hens that had observed cockerels performed very few general pecks or operant pecks. Hens that had observed dominant hens performed more operant pecks, but hens that had observed sub-ordinate hens performed more general pecks in the chamber. The results suggested either that there was an interaction between dominance and gender in demonstrator salience or that dominant hens might have been influential because of some factor imperfectly associated with their dominance status. A possible candidate was the foraging ability of the dominant hens. In a second experiment using the same protocol, we manipulated the prior foraging success of dominant hens from four additional flocks but this had no significant effect on their subsequent influence as demonstrators. Copyright 1999 The Association for the Study of Animal Behaviour.     

Effects of social support during parturition on maternal and infant morbidity.

Because continuous social support during labour is a component of care in many societies but inconsistent in our own, the clinical effect of support during labour on maternal and neonatal morbidity were studied. Social support was provided by female companions. Four hundred and sixty five healthy primigravidous women were enrolled using a randomised design. Compared with 249 women undergoing labour alone 168 women who had supportive female companions throughout labour had significantly fewer perinatal complications (p less than 0.001), including caesarean sections (7% v 17%, p less than 0.01) and oxytocin augmentation (2% v 13%, p less than 0.001), and fewer infants admitted to neonatal intensive care (p less than 0.10). Of the women who had an uncomplicated labour and delivery requiring no interventions, those with a companion had a significantly shorter duration of labour (7.7 hours v 15.5 hours, p less than 0.001). This study suggests that constant human support may be of great benefit to women during labour.     

Effects of placental malaria on mothers and neonates from Zaire

Of one hundred placentas collected consecutively in the Ubangi district, Zaire, 64 had falciparum malaria. Mothers and infants of the 64 malarious and 36 non-malarious placentas were compared. The malarious placentas had no consistent relationship to infant length or head circumference, APGAR score, birthweight, maternal anemia, splenomegaly or hydramnios. The rate of hydramnios, in fact, was higher in the mothers with non-malarious placentas. Mothers with malarious placentas were younger (means 24) than mothers with non-malarious placentas (means 29). Mothers with fewer pregnancies were more likely to have malarious placentas than older multiparous mothers. There were 7 stillbirths, 4 from mothers with malarious placentas. Infants born to mothers with malarious placentas averaged 100 g less than those from mothers with non-malarious placentas. This study shows that mothers with falciparum malaria from the Ubangi district deliver normal and apparently unaffected infants.     

The relationship between body mass index and unhealthy weight control behaviors among adolescents: The role of family and peer social support

Adolescents classified as overweight or obese are more likely to use unhealthy weight control behaviors such as skipping meals or fasting than their healthy weight peers. Adolescents with low perceived social support may be at particular risk. Therefore, the purpose of the present study was to investigate the association between adolescent overweight and obesity, indices of perceived peer and family social support, and their interaction in the use of unhealthy weight control behaviors among adolescents. The present study used data from the 2001–2002 Health Behavior in School-Aged Children collaborative survey. Participants included 4598 adolescent girls and boys in the ninth and tenth grades. Results of binary logistic regression analyses showed that obese boys and girls were more likely to use unhealthy weight control behaviors than their healthy weight peers. Boys and girls who endorsed difficult communication with their parents, low levels of parent school support, or frequent bullying were more likely to engage in unhealthy weight control behaviors than relevant comparison groups. Among girls, poor classmate relationships were associated with increased use of unhealthy weight control behaviors whereas fewer friendships were associated with decreased use. Results suggest that adolescents are at high risk for use of unhealthy weight control behaviors and would benefit from interventions to increase knowledge and social support for achieving and maintaining a healthy weight.