Does prey size matter? Novel observations of feeding in the leatherback turtle (Dermochelys coriacea) allow a test of predator–prey size relationships

Optimal foraging models predict that large predators should concentrate on large prey in order to maximize their net gain of energy intake. Here, we show that the largest species of sea turtle, Dermochelys coriacea, does not strictly adhere to this general pattern. Field observations combined with a theoretical model suggest that a 300 kg leatherback turtle would meet its energetic requirements by feeding for 3–4 h a day on 4 g jellyfish, but only if prey were aggregated in high-density patches. Therefore, prey abundance rather than prey size may, in some cases, be the overriding parameter for foraging leatherbacks. This is a classic example where the presence of small prey in the diet of a large marine predator may reflect profitable foraging decisions if the relatively low energy intake per small individual prey is offset by high encounter rates and minimal capture and handling costs. This study provides, to our knowledge, the first quantitative estimates of intake rate for this species.

ICT Interventions for Schoolgirls Do Matter! Understanding the Factors Influencing ICT Career Intentions through Partial Least Squares Analysis.

Intervention programs aimed at promoting study and work opportunities in the Information and Communications Technology (ICT) field to schoolgirls (Interventions) have been encouraged to combat a decline in the interest among girls to study ICT at school. The goal of our study is to investigate the influence of Interventions on schoolgirls’ intentions to choose a career in the ICT field by analysing the  comprehensive survey data (n = 3577), collected during four interventions in Australia, using the Partial Least Squares method. Our study is also aimed at identifying other factors influencing ICT career intentions. We found that the attitude towards interventions has an indirect influence on ICT career intentions by affecting interest in ICT. Our results also challenge several existing theoretical studies by showing that factors that had previously been suggested as influencers were found to have little or no impact in this study, these being same-sex education and computer usage.

Sex does not matter: gender bias and gender differences in peer assessments of contributions to group work

This paper considers the possibility of gender bias in peer ratings for contributions to team assignments, as measured by an online self-and-peer assessment tool. The research was conducted to determine whether peer assessment led to reliable and fair marking outcomes. The methodology of Falchikov and Magin was followed in order to test their finding that gender has no discernable impact on peer ratings. Data from over 1500 participants at two universities enrolled in four different degree programmes were analysed. The research indicates an absence of gender bias in six case studies. The research also found that women received significantly higher ratings than men.

Organisational and professional commitment of early career accountants: do mentoring and organisational ethical climate matter?

This study assesses the effects of mentoring and organisational ethical climate (OEC) on the organisational and professional commitment (PC) of early career accountants (ECAs) (i.e. accounting graduate recruits with three or less years of working experience). The empirical data are based on a questionnaire survey from 86 ECAs in Australian public accounting firms, and hypothesis testing utilises partial least squares analysis. Our results indicate when a career development style of mentoring is adopted there is greater organisational as well as PC. By contrast, a social support mentoring style has no significant impact on organisational commitment (OC) and a negative effect on PC. Further, our data also reveal OEC to be positively associated with OC, and OC in turn having a positive impact on PC. The results imply that fostering a career-focused mentoring environment and an OEC can increase an ECA's OC and PC. These results have various implications for human resource management at both the accounting firm and professional levels.

Describing socioeconomic gradients in children's diets - does the socioeconomic indicators used matter?

Background: 

Does size matter? Sex differences in white-faced storm petrels’ ecology

Does size matter? In the case of the white-faced storm petrel, yes, it would appear so. The findings of this study make a significant contribution to further our understanding of how even subtle sexual size dimorphism influences aspects of this species’ biology and ecology, and how this relates across Procellariiformes.

Does gender matter? A one year follow-up of autistic, attention and anxiety symptoms in high-functioning children with autism spectrum disorder

Gender differences in autism spectrum disorder (ASD) symptoms and associated problem behaviours over development may provide clues regarding why more males than females are diagnosed with ASD. Fifty-six high-functioning children with ASD, and 44 typically developing controls, half of the participants female, were assessed at baseline (aged 7–12 years) and one-year later, collecting measures of autism, attention and anxiety symptoms, school placement and support information. Findings indicated no gender differences in autistic symptoms. Males were more hyperactive and received more integration-aide support in mainstream schools, and females were more socially anxious. Overall, similar gender profiles were present across two time points. Lower hyperactivity levels in females might contribute to their under-identification. Implications are discussed using a biopsychosocial model of gender difference.

Does timing matter? How priority effects influence the outcome of parasite interactions within hosts

In nature, hosts are exposed to an assemblage of parasite species that collectively form a complex community within the host. To date, however, our understanding of how within-host–parasite communities assemble and interact remains limited. Using a larval amphibian host (Pacific chorus frog, Pseudacris regilla) and two common trematode parasites (Ribeiroia ondatrae and Echinostoma trivolvis), we experimentally examined how the sequence of host exposure influenced parasite interactions within hosts. While there was no evidence that the parasites interacted when hosts were exposed to both parasites simultaneously, we detected evidence of both intraspecific and interspecific competition when exposures were temporally staggered. However, the strength and outcome of these priority effects depended on the sequence of addition, even after accounting for the fact that parasites added early in host development were more likely to encyst compared to parasites added later. Ribeiroia infection success was reduced by 14 % when Echinostoma was added prior to Ribeiroia, whereas no such effect was noted for Echinostoma when Ribeiroia was added first. Using a novel fluorescent-labeling technique that allowed us to track Ribeiroia infections from different exposure events, we also discovered that, similar to the interspecific interactions, early encysting parasites reduced the encystment success of later arriving parasites by 41 %, which could be mediated by host immune responses and/or competition for space. These results suggest that parasite identity interacts with host immune responses to mediate parasite interactions within the host, such that priority effects may play an important role in structuring parasite communities within hosts. This knowledge can be used to assess host–parasite interactions within natural communities in which environmental conditions can lead to heterogeneity in the timing and composition of host exposure to parasites.

Cocaine use severity and cerebellar gray matter are associated with reversal learning deficits in cocaine-dependent individuals

Cocaine addiction involves persistent deficits to unlearn previously rewarded response options, potentially due to neuroadaptations in learning-sensitive regions. Cocaine-targeted prefrontal systems have been consistently associated with reinforcement learning and reversal deficits, but more recent interspecies research has raised awareness about the contribution of the cerebellum to cocaine addiction and reversal. We aimed at investigating the link between cocaine use, reversal learning and prefrontal, insula and cerebellar gray matter in cocaine-dependent individuals (CDIs) varying on levels of cocaine exposure in comparison with healthy controls (HCs). Twenty CDIs and 21 HCs performed a probabilistic reversal learning task (PRLT) and were subsequently scanned in a 3-Tesla magnetic resonance imaging scanner. In the PRLT, subjects progressively learn to respond to one predominantly reinforced stimulus, and thenmust learn to respond according to the opposite, previously irrelevant, stimulus-reward pairing. Performance measureswere errors after reversal (reversal cost), and probability of maintaining response after errors. Voxel-based morphometry was conducted to investigate the association between gray matter volume in the regions of interest and cocaine use and PRLT performance. Severity of cocaine use correlated with gray matter volume reduction in the left cerebellum (lobule VIII), while greater reversal cost was correlated with gray matter volume reduction in a partially overlapping cluster (lobules VIIb and VIII). Right insula/inferior frontal gyrus correlated with probability of maintaining response after errors. Severity of cocaine use detrimentally impacted reversal learning and cerebellar gray matter.