Sex differences in young children’s use of tools in a problem-solving task

Three-year-old children were observed in two free-play sessions and participated in a toy-retrieval task, in which only one of six tools could be used to retrieve an out-of-reach toy. Boys engaged in more object-oriented play than girls and were more likely to use tools to retrieve the toy during the baseline tool-use task. All children who did not retrieve the toy during the baseline trials did so after being given a hint, and performance on a transfer-of-training tool-use task approached ceiling levels. This suggests that the sex difference in tool use observed during the baseline phase does not reflect a difference in competency, but rather a sex difference in motivation to interact with objects. Amount of time boys, but not girls, spent in object-oriented play during the free-play sessions predicted performance on the tool-use task. The findings are interpreted in terms of evolutionary theory, consistent with the idea that boys’ and girls’ play styles evolved to prepare them for adult life in traditional environments.     

Sex differences in body size and body condition in breeding Temminck’s Stints Calidris temminckii

There have been very few reports of body size measurements of live Temminck’s Stints, but earlier studies have shown sex differences in body mass and tarsus length. Here we use molecular techniques to determine the sex of Temminck’s Stints from a Norwegian breeding population. In total, we report measurements of body weight, wing length, tarsus length, bill length, skull length and keel length from 17 males and 30 females. We found significant sex differences in all of these variables, with the exception of tarsus length. The differences in skull length disappeared after the bill lengths had been subtracted from the measurements. A discriminant function analysis based on wing length and bill length correctly classified 86% of the cases (12/16 males, 25/27 females). Female Temminck’s Stints are known to regularly lay more than one clutch of eggs per season and could therefore be expected to be physiologically deprived of bodily energy stores. Nevertheless, we found females to be in better body condition than males.     

Catecholamine metabolism in children with Asperger’s and Kanner’s syndromes

In a stable state children with Asperger’s and Kanner’s syndromes demonstrate a similar decrease in plasma norepinephrine. In the aggravated state, these changes become more expressed and are characterized by a decrease in plasma tyrosine, norepinephrine, normetanephrine, and by an increase in dopamine and homovanillic acid and a decrease in excretion of norepinephrine and an increase in excretion of homovanillic acid, epinephrine and 3-methoxy-4-hydroxyphenylglycol (MHPG). In the aggravated state children with Kanner’s syndrome were characterized by increased plasma MHPG, decreased excretion of tyrosine and increased expression of normetanephrine. The observed imbalance in dopamine and epinephrine/norepinephrine systems suggests importance of combined analysis of changes in catecholamines and their metabolites as the most informative approach in the study of the effect of autistic disorders.     

Partner Status Influences Women’s Interest in the Opposite Sex

Previous research has demonstrated that hormones, relationship goals, and social context influence interest in the opposite sex. It has not been previously reported, however, whether having a current sexual partner also influences interest in members of the opposite sex. To test this, we obtained explicit and implicit measures of interest by measuring men’s and women’s subjective ratings and response times while they evaluated photos of opposite-sex faces. Fifty-nine men and 56 women rated 510 photos of opposite-sex faces for realism, masculinity, attractiveness, or affect. We found that these subjective ratings were not influenced by partner status in either men or women. However, women who did not report having a current sexual partner spent more time evaluating the photos than women who did have partners, demonstrating greater interest in the photos. Sexual partner status did not predict men’s response times. These findings may reveal that relationship commitment in women suppresses interest in alternative partners.

Sex differences in Adélie penguin foraging strategies

Consistent sex differences in foraging trip duration, feeding locality and diet of breeding Adélie penguins (Pygoscelis adeliae) were demonstrated at two widely separated locations over several breeding seasons. Differences in foraging behaviour were most pronounced during the guard stage of chick rearing. Female penguins made on average longer foraging trips than males, ranged greater distances more frequently and consumed larger quantities of krill. In contrast, males made shorter journeys to closer foraging grounds during the guard period and fed more extensively on fish throughout chick rearing. Mean guard stage foraging trip durations over four seasons at Béchervaise Island, Eastern Antarctica and over two seasons at Edmonson Point, Ross Sea ranged between 31 and 73 h for females and 25 and 36 h for males. Ninety percent of males tracked from Béchervaise Island by satellite during the first 3 weeks post-hatch foraged within 20 km of the colony, while the majority (60%) of females travelled to the edge of the continental shelf (80–120 km from the colony) to feed during this period. Received: 10 December 1997 / Accepted: 10 April 1998     

Sex differences in cannabinoid pharmacology: A reflection of differences in the endocannabinoid system?

Marijuana is the most widely used illicit drug in the U.S., and marijuana use by women is on the rise. Women have been found to be more susceptible to the development of cannabinoid abuse and dependence, have more severe withdrawal symptoms, and are more likely to relapse than men. The majority of research in humans suggests that women are more likely to be affected by cannabinoids than men, with reports of enhanced and decreased performance on various tasks. In rodents, females are more sensitive than males to effects of cannabinoids on tests of antinociception, motor activity, and reinforcing efficacy. Studies on effects of cannabinoid exposure during adolescence in both humans and rodents suggest that female adolescents are more likely than male adolescents to be deleteriously affected by cannabinoids. Sex differences in response to cannabinoids appear to be due to activational and perhaps organizational effects of gonadal hormones, with estradiol identified as the hormone that contributes most to the sexually dimorphic effects of cannabinoids in adults. Many, but not all sexually dimorphic effects of exogenous cannabinoids can be attributed to a sexually dimorphic endocannabinoid system in rodents, although the same has not yet been established firmly for humans. A greater understanding of the mechanisms underlying sexually dimorphic effects of cannabinoids will facilitate development of sex-specific approaches to treat marijuana dependence and to use cannabinoid-based medications therapeutically.     

Sex differences in anogenital distances and digit ratios in wild David＇s rock squirrels Sciurotamias davidianus

The prenatal hormonal environment plays an important role in organizing sex differences in the morphology, physiology and behavior of humans as well as other vertebrates. Currently, all related research on rodents has been focused on Myomorpha. This study presents data on sex differences in the anogenital distance （AGD） and the ratio of the second to the fourth digit length （2D：4D） from 44 wild David＇s rock squirrels Sciurotamias davidianus captured from the Qinling Mountains, China. This was the first study of a species from Sciuromorpha. The AGD as well as body mass are sexually dimorphic. There are no sex differences or lateral asymmetry in 2D：4D. Significant correlation was not found between AGD and 2D：4D for any paw. The findings indicate that 2D：4D may not be fixed or influenced by the prenatal steroidal environment in David＇s rock squirrels [Current Zoology 60 （2）： 180-185, 2014].     

Parental nonemployment in childhood and children’s health later in life

While the effects of joblessness on the health of the non-employed are well-documented, its long-term spillover consequences on the health of their relatives, especially children, remain poorly understood. This research explores the long-term associations of parental nonemployment spells experienced during early, mid and late childhood on children’s mental and physical health. The analysis exploits data drawn from the British Household Panel Survey (BHPS) and the UK Household Longitudinal Study (UKHLS), linking detailed parental socioeconomic information with their children between the years 1993 and 2013. This paper employs a Correlated Random Effects (CRE) probit model that allows accounting for unobserved heterogeneity as well as a non-linear Generalized Estimating Equations (GEE) random effects estimator accounting in addition for the dependency structure of the data. Results indicate that experiencing parental nonemployment during early and late childhood has a negative association on the children’s likelihood of suffering from long-standing illnesses later in life, while experiencing parental nonemployment during middle childhood negatively affects the young adult’s mental health. Moreover, experiencing parental nonemployment during late childhood increases the probability of both reporting poor or fair self-assessed health and the likelihood of consuming prescribed medicines in early adulthood. However, there seems to be a considerable effect heterogeneity by family socioeconomic status, parents’ gender, and frequencies of parental nonemployment spells. Current adulthood circumstances, such as level of educational attainment, job situation and household demographics, are used to explore the potential mechanisms affecting results. These findings may help policymakers shape appropriate responses to mitigate the psychological and physical burden derived from parental nonemployment, especially among already disadvantaged households.     

Young children’s understanding of plant life: a study exploring rural–urban differences in their drawings

Drawing activities are believed to be a useful methodology to gain insight into young children’s thoughts and ideas related to a diverse range of research topics. In this respect, the study of drawings has proven to be a valuable procedure with a view to unravelling how the natural world is conceptualised in early childhood. The present study examines the content of the drawings that 328 Spanish children aged between of 4 and 7 carried out in their bid to express their understanding of plant life and the data collected is related to the potential for connecting with nature which may be offered by the location of their educational centres. The results show slight but significant differences between the depictions undertaken by the children attending schools in rural environments, and those made by their peer group in urban centres. The evidence and conclusions of the study are coherent with the assumption that as early as kindergarten age, children are well involved in attempting to give meaning to their nature-based experiences.     

Parkinson’s disease and sex-related differences in electromyography during daily life

Scope: Daily bilateral electromyography (EMG) recordings reveal muscle activation patterns implicated in asymmetric Parkinson’s disease (PD)-related functional decline. Also, daily EMG recordings reveal sex-differences in muscle activity that give rise to unique PD presentation in males and females. Purpose: Quantify handgrip strength and daily muscle quiescence through analysis of gaps in the EMG signal in males and females with PD. Bilateral daily EMG was recorded and normalized to maximal voluntary exertions (MVE). EMG gap was defined as <1% amplitude of MVE for >0.1 s and characterized as number, duration and time occupied by gaps. A dynamometer evaluated maximal grip-strength. Three-way repeated measures ANOVA examined differences in gap characteristics and strength. Gap duration was shorter (p = 0.04) and occupied less time (p = 0.02) in PD than controls. Females had fewer gaps with shorter duration (p = 0.004), occupying less time (p = 0.004) compared with males. Gaps were fewer (p = 0.04) and occupied less time (p = 0.01) on more-affected than less-affected side. PD was weaker than controls (p = 0.04), females were weaker than males (p = 0.00), and the more-affected PD side was weaker than less-affected (p = 0.04). Conclusions: Quantification of muscle quiescence through gaps in the EMG signal recorded during daily life provides insight into mechanisms underlying differential change in functional performance in males and females with PD.     

Sex differences in vasopressin V₂ receptor expression and vasopressin-induced antidiuresis

The renal vasopressin V(2) receptor (V(2)R) plays a critical role in physiological and pathophysiological processes associated with arginine vasopressin (AVP)-induced antidiuresis. Because clinical data suggests that females may be more prone to hyponatremia from AVP-mediated antidiuresis, we investigated whether there are sex differences in the expression and function of the renal V(2)R. In normal Sprague-Dawley rat kidneys, V(2)R mRNA and protein expression was 2.6- and 1.7-fold higher, respectively, in females compared with males. To investigate the potential physiological implications of this sex difference, we studied changes in urine osmolality induced by the AVP V(2)R agonist desmopressin. In response to different doses of desmopressin, there was a graded increase in urine osmolality and decrease in urine volume during a 24-h infusion. Females showed greater mean increases in urine osmolality and greater mean decreases in urine volume at 0.5 and 5.0 ng/h infusion rates. We also studied renal escape from antidiuresis produced by water loading in rats infused with desmopressin (5.0 ng/h). After 5 days of water loading, urine osmolality of both female and male rats escaped to the same degree physiologically, but V(2)R mRNA and protein in female kidneys was reduced to a greater degree (-63% and -73%, respectively) than in males (-32% and -48%, respectively). By the end of the 5-day escape period, renal V(2)R mRNA and protein expression were reduced to the same relative levels in males and females, thereby abolishing the sex differences in V(2)R expression seen in the basal state. Our results demonstrate that female rats express significantly more V(2)R mRNA and protein in kidneys than males, and that this results physiologically in a greater sensitivity to V(2)R agonist administration. The potential pathophysiological implications of these results are that females may be more susceptible to the development of dilutional hyponatremia because of a greater sensitivity to endogenously secreted AVP.     

Sex‐specific differences in Sand Martin Riparia riparia nest attentiveness

Capsule Nest attentiveness during the night is significantly lower in males but varies with the activities of the breeding cycle. Male nest attentiveness shows minima during the burrowing and egg‐laying phases, and also during the brooding of chicks in second or re‐nest broods.     

Habitat- and sex-related differences in a small carnivore’s diet in a competitor-free environment

The alien invasive American mink Neovison vison is fully established in the low species richness and competitor-free environment of Iceland. This study documents the diversity as well as seasonal and sexual variation in the diet of mink in Iceland based on stomach contents. Seasonal changes mainly reflected variation in abundance of migratory birds and wood mice Apodemus sylvaticus. In comparison with mink elsewhere in similar habitats, the mink in Iceland consumed more fish and birds and fewer mammals, which is in accordance with local availability. This reinforces evidence of opportunistic foraging. Females generally ate more fish and fewer birds than males and this might be explained by their smaller body size and possible limitation in catching larger birds. Mink in coastal habitats showed greater sexual differences in diet than mink in riparian habitats, probably reflecting less prey diversity in riparian habitats than coastal ones. This study is an input towards explaining the ecological consequences of sexual size dimorphism and supports the hypothesis that generalist species might be successful invaders due to their capability in utilising new and diverse resources. The mink in Iceland can be regarded as a model for a small-bodied semi-aquatic carnivore away from the confounding effects of inter-specific competition.     

Other people’s children: inclusive parenting in a diversified neighbourhood in Norway

ABSTRACT

This article explores how parents include other people’s children in intensive parenting practices. Increased diversification of Norwegian society calls attention to opportunities for social mobility and the risk of greater inequality. However, insufficient research has been carried out into how parents pursue parenting in such a context. How are parenting practices informed by increased diversity? Why and how do parents become engaged with other people’s children? This study explores the concept of intensive parenting, which researchers view as commonplace among Western middle-class parents, and which leads to individualizing parenting. It argues that for some, intensive parenting also incorporates inclusive parenting – a responsibility not only towards their own child, but a concern for and time investment in other people’s children. This parenting style is linked to a desire to create a more egalitarian society, and a belief that a child’s upbringing and future depends upon the wellbeing of other people’s children.     

Assessing the impact of fostering on children’s outcomes in Niger

This article measures the impact of fostering on children’s outcomes in Niger. We estimate a simultaneous equations model with three outcomes for children (school attendance, hours of market work and hours of domestic work) and a treatment variable (fostering). Nonlinearity provides identification by functional form of the causal effect of fostering. We further use information on the historical level of community integration of the child’s ethnicity and the relative importance of the ethnicity in the neighborhood to build a plausibly exogenous exclusion restriction in order to correct for the potential endogeneity of fostering. Our results sustain the overall conclusion that fostering has a positive impact on children’s school attendance and hours of domestic work. However, while foster boys and girls are both engaged in longer hours of domestic labor, only foster boys are advantaged in terms of schooling.     

The Heart´s rhythm ‘n’ blues: Sex differences in circadian variation patterns of vagal activity vary by depressive symptoms in predominantly healthy employees

Introduction: Successful regulation of emotional states is positively associated to mental health, while difficulties in regulating emotions are negatively associated to overall mental health and in particular associated with anxiety or depression symptoms. A key structure associated to socio-emotional regulatory processes is the central autonomic network. Activity in this structure is associated to vagal activity can be indexed noninvasively and simply by measures of peripheral cardiac autonomic modulations such as heart rate variability. Vagal activity exhibits a circadian variation pattern, with a maximum during nighttime.

Depression is known to affect chronobiology. Also, depressive symptoms are known to be associated with decreased resting state vagal activity, but studies investigating the association between circadian variation pattern of vagal activity and depressive symptoms are scarce. We aim to examine these patterns in association to symptom severity of depression using chronobiologic methods.

Methods: Data from the Manheim Industrial Cohort Studies (MICS) were used. A total of 3,030 predominantly healthy working adults underwent, among others, ambulatory 24-h hear rate-recordings, detailed health examination and online questionnaires and were available for this analysis. The root mean sum of successive differences (RMSSD) was used as an indicator of vagally mediated heart rate variability. Three individual-level cosine function parameters (MESOR, amplitude, acrophase) were estimated to quantify circadian variation pattern. Multivariate linear regression models including important covariates such as age, sex, and lifestyle factors as well as an interaction effect of sex with depressive symptoms were used to estimate the association of circadian variation pattern of vagal activity with depressive symptoms simultaneously.

Results: The analysis sample consisted of 20.2% females and an average age 41 with standard deviation of 11 years. Nonparametric bivariate analysis revealed significant MESOR and amplitude differences between the 90^th percentile split, but not on acrophase.

Multivariate linear regression models estimated depressive symptoms to be negatively associated with the 24h mean (MESOR) and oscillation amplitude in men but positively associated in women. This pattern of findings indicates a blunted day-night rhythm of vagal activity in men with greater depressive symptoms as well as a moderation effect of sex in the association of CVP and depressive symptoms.

Conclusions: This is the first study investigating circadian variation pattern by mild depressive symptoms in a large, rather healthy occupational sample. Depressive symptoms were associated with decreased circadian variation pattern of vagal activity in men but with increased circadian variation pattern in women. The possible underlying mechanism(s) are discussed using the neurovisceral integration model. These findings may have implications for the knowledge on etiology, diagnosis, course, and treatment of depressive symptoms and thus may be of significant public health relevance.     

Sex differences in human adipose tissues – the biology of pear shape

Women have more body fat than men, but in contrast to the deleterious metabolic consequences of the central obesity typical of men, the pear-shaped body fat distribution of many women is associated with lower cardiometabolic risk. To understand the mechanisms regulating adiposity and adipose tissue distribution in men and women, significant research attention has focused on comparing adipocyte morphological and metabolic properties, as well as the capacity of preadipocytes derived from different depots for proliferation and differentiation. Available evidence points to possible intrinsic, cell autonomous differences in preadipocytes and adipocytes, as well as modulatory roles for sex steroids, the microenvironment within each adipose tissue, and developmental factors. Gluteal-femoral adipose tissues of women may simply provide a safe lipid reservoir for excess energy, or they may directly regulate systemic metabolism via release of metabolic products or adipokines. We provide a brief overview of the relationship of fat distribution to metabolic health in men and women, and then focus on mechanisms underlying sex differences in adipose tissue biology.     

Preschool-aged children’s jumps: Imitation performances

Imitative behavior underlaid by perception and action links during children’s development in complex locomotor skills has been the object of relatively few studies. In order to explore children’s motor coordination modes, 130 children divided into five age groups from 3.5 to 7.5 years were instructed to imitate jumping tasks in spontaneous motor situation and in various imitative contexts by an adult providing verbal orders and gestural demonstrations. Their conformity to the model, stability and variability scores were coded from a video analysis when they performed jumps with obstacles. To evaluate their postural-motor control level, the durations of the preparatory phase and jumping flights were also timed. Results showed that all age groups generated the demonstrator’s goal but not necessarily the same coordination modes of jumping. In imitation with temporal proximity, the model helped the youngest age groups to adopt his coordination modes and stabilized only the oldest age groups’ performances starting from 5.5 years old, without effect on learning imitation. Differences between the youngest and oldest children in the jump duration suggested that the reproduction of a complex motor activity such as jumping with a one foot take-off would require resolution and adjustment of main postural stability.