Development of a cognitive bias methodology for measuring low mood in chimpanzees
There is an ethical and scientific need for objective, well-validated measures of low mood in captive chimpanzees. We describe the development of a novel cognitive task designed to measure ‘pessimistic’ bias in judgments of expectation of reward, a cognitive marker of low mood previously validated in a wide range of species, and report training and test data from three common chimpanzees (Pan troglodytes). The chimpanzees were trained on an arbitrary visual discrimination in which lifting a pale grey paper cone was associated with reinforcement with a peanut, whereas lifting a dark grey cone was associated with no reward. The discrimination was trained by sequentially presenting the two cone types until significant differences in latency to touch the cone types emerged, and was confirmed by simultaneously presenting both cone types in choice trials. Subjects were subsequently tested on their latency to touch unrewarded cones of three intermediate shades of grey not previously seen. Pessimism was indicated by the similarity between the latency to touch intermediate cones and the latency to touch the trained, unreinforced, dark grey cones. Three subjects completed training and testing, two adult males and one adult female. All subjects learnt the discrimination (107–240 trials), and retained it during five sessions of testing. There was no evidence that latencies to lift intermediate cones increased over testing, as would have occurred if subjects learnt that these were never rewarded, suggesting that the task could be used for repeated testing of individual animals. There was a significant difference between subjects in their relative latencies to touch intermediate cones (pessimism index) that emerged following the second test session, and was not changed by the addition of further data. The most dominant male subject was least pessimistic, and the female most pessimistic. We argue that the task has the potential to be used to assess longitudinal changes in sub-clinical levels of low mood in chimpanzees, however further work with a larger sample of animals is required to validate this claim.
Bateson et al. (2015) Development of a cognitive bias methodology for measuring low mood in chimpanzees. PeerJ 3:e998 https://doi.org/10.7717/peerj.998
A rapid assessment of post-disclosure experiences of urban HIV-positive and HIV-negative school-aged children in Kenya
There has been limited involvement of HIV-negative children in HIV disclosure studies; most studies conducted on the effects of disclosure on children have been with HIV-positive children and HIV-positive mother-child dyads. Seven HIV-positive and five HIV-negative children participated in a larger study conducted to understand the lived experiences of HIV-positive parents and their children during the disclosure process in Kenya. In this study, the experiences of these 12 children after receiving disclosure of their own and their parents’ illnesses respectively are presented. Each child underwent an in-depth qualitative semi-structured digitally recorded interview. The recorded interviews were transcribed and loaded into NVivo8 for phenomenological data analysis. Five themes emerged from the data, indicating that HIV-positive and negative children appear to have differing post-disclosure experiences revolving around acceptance of illness, stigma and discrimination, medication consumption, sexual awareness, and use of coping mechanisms. Following disclosure, HIV-negative children accepted their parents’ illnesses within a few hours to a few weeks; HIV-positive children took weeks to months to accept their own illnesses. HIV-negative children knew of high levels of stigma and discrimination within the community; HIV-positive children reported experiencing indirect incidences of stigma and discrimination. HIV-negative children wanted their parents to take their medications, stay healthy, and pay their school fees so they could have a better life in the future; HIV-positive children viewed medication consumption as an ordeal necessary to keep them healthy. HIV-negative children wanted their parents to speak to them about sexual-related matters; HIV-positive children had lingering questions about relationships, use of condoms, marriage, and childbearing options. All but one preadolescent HIV-positive child had self-identified a person to speak with for social support. When feeling overwhelmed by their circumstances, the children self-withdrew and performed positive activities (e.g., praying, watching TV, listening to the radio, singing, dancing) to help themselves feel better. Many HIV-affected families have a combination of HIV-positive and negative siblings within the household. Pending further studies conducted with larger sample sizes, the results of this study should assist healthcare professionals to better facilitate disclosure between HIV-positive parents and their children of mixed HIV statuses.
Gachanja (2015) A rapid assessment of post-disclosure experiences of urban HIV-positive and HIV-negative school-aged children in Kenya. PeerJ 3:e956 https://doi.org/10.7717/peerj.956
Pyrosequencing revealed shifts of prokaryotic communities between healthy and disease-like tissues of the Red Sea sponge Crella cyathophora
Sponge diseases have been widely reported, yet the causal factors and major pathogenic microbes remain elusive. In this study, two individuals of the sponge Crella cyathophora in total that showed similar disease-like characteristics were collected from two different locations along the Red Sea coast separated by more than 30 kilometers. The disease-like parts of the two individuals were both covered by green surfaces, and the body size was much smaller compared with adjacent healthy regions. Here, using high-throughput pyrosequencing technology, we investigated the prokaryotic communities in healthy and disease-like sponge tissues as well as adjacent seawater. Microbes in healthy tissues belonged mainly to the Proteobacteria, Cyanobacteria and Bacteroidetes, and were much more diverse at the phylum level than reported previously. Interestingly, the disease-like tissues from the two sponge individuals underwent shifts of prokaryotic communities and were both enriched with a novel clade affiliated with the phylum Verrucomicrobia, implying its intimate connection with the disease-like Red Sea sponge C. cyathophora. Enrichment of the phylum Verrucomicrobia was also considered to be correlated with the presence of algae assemblages forming the green surface of the disease-like sponge tissues. This finding represents an interesting case of sponge disease and is valuable for further study.
Gao et al. (2015) Pyrosequencing revealed shifts of prokaryotic communities between healthy and disease-like tissues of the Red Sea sponge Crella cyathophora. PeerJ 3:e890 https://doi.org/10.7717/peerj.890
Can sea urchins beat the heat? Sea urchins, thermal tolerance and climate change
The massive die-off of the long-spined sea urchin, Diadema antillarum, a significant reef grazer, in the mid 1980s was followed by phase shifts from coral dominated to macroalgae dominated reefs in the Caribbean. While Diadema populations have recovered in some reefs with concomitant increases in coral cover, the additional threat of increasing temperatures due to global climate change has not been investigated in adult sea urchins. In this study, I measured acute thermal tolerance of D. antillarum and that of a sympatric sea urchin not associated with coral cover, Echinometra lucunter, over winter, spring, and summer, thus exposing them to substantial natural thermal variation. Animals were taken from the wild and placed in laboratory tanks in room temperature water (∼22 °C) that was then heated at 0.16–0.3 °C min−1 and the righting behavior of individual sea urchins was recorded. I measured both the temperature at which the animal could no longer right itself (TLoR) and the righting time at temperatures below the TLoR. In all seasons, D. antillarum exhibited a higher mean TLoR than E. lucunter. The mean TLoR of each species increased with increasing environmental temperature revealing that both species acclimatize to seasonal changes in temperatures. The righting times of D. antillarum were much shorter than those of E. lucunter. The longer relative spine length of Diadema compared to that of Echinometra may contribute to their shorter righting times, but does not explain their higher TLoR. The thermal safety margin (the difference between the mean collection temperature and the mean TLoR) was between 3.07–3.66 °C for Echinometra and 3.79–5.67 °C for Diadema. While these thermal safety margins exceed present day temperatures, they are modest compared to those of temperate marine invertebrates. If sea temperatures increase more rapidly than can be accommodated by the sea urchins (either by genetic adaptation, phenotypic plasticity, or both), this will have important consequences for the structure of coral reefs.
Sherman (2015) Can sea urchins beat the heat? Sea urchins, thermal tolerance and climate change. PeerJ 3:e1006 https://doi.org/10.7717/peerj.1006
A mathematical model for predicting glucose levels in critically-ill patients: the PIGnOLI model
Background and Objectives. Glycemic control is of paramount importance in the intensive care unit. Presently, several BG control algorithms have been developed for clinical trials, but they are mostly based on experts’ opinion and consensus. There are no validated models predicting how glucose levels will change after initiating of insulin infusion in critically ill patients. The study aimed to develop an equation for initial insulin dose setting. Methods. A large critical care database was employed for the study. Linear regression model fitting was employed. Retested blood glucose was used as the independent variable. Insulin rate was forced into the model. Multivariable fractional polynomials and interaction terms were used to explore the complex relationships among covariates. The overall fit of the model was examined by using residuals and adjusted R-squared values. Regression diagnostics were used to explore the influence of outliers on the model. Main Results. A total of 6,487 ICU admissions requiring insulin pump therapy were identified. The dataset was randomly split into two subsets at 7 to 3 ratio. The initial model comprised fractional polynomials and interactions terms. However, this model was not stable by excluding several outliers. I fitted a simple linear model without interaction. The selected prediction model (Predicting Glucose Levels in ICU, PIGnOLI) included variables of initial blood glucose, insulin rate, PO volume, total parental nutrition, body mass index (BMI), lactate, congestive heart failure, renal failure, liver disease, time interval of BS recheck, dextrose rate. Insulin rate was significantly associated with blood glucose reduction (coefficient: −0.52, 95% CI [−1.03, −0.01]). The parsimonious model was well validated with the validation subset, with an adjusted R-squared value of 0.8259. Conclusion. The study developed the PIGnOLI model for the initial insulin dose setting. Furthermore, experimental study is mandatory to examine whether adjustment of the insulin infusion rate based on PIGnOLI will benefit patients’ outcomes.
Zhang (2015) A mathematical model for predicting glucose levels in critically-ill patients: the PIGnOLI model. PeerJ 3:e1005 https://doi.org/10.7717/peerj.1005
Beliefs and attitudes towards mental illness: an examination of the sex differences in mental health literacy in a community sample
Objectives. The current study investigated mental health literacy in an Australian sample to examine sex differences in the identification of and attitudes towards various aspects of mental illness. Method. An online questionnaire was completed by 373 participants (M = 34.87 years). Participants were randomly assigned either a male or female version of a vignette depicting an individual exhibiting the symptoms of one of three types of mental illness (depression, anxiety, or psychosis) and asked to answer questions relating to aspects of mental health literacy. Results. Males exhibited poorer mental health literacy skills compared to females. Males were less likely to correctly identify the type of mental illness, more likely to rate symptoms as less serious, to perceive the individual as having greater personal control over such symptoms, and less likely to endorse the need for treatment for anxiety or psychosis. Conclusion. Generally, the sample was relatively proficient at correctly identifying mental illness but overall males displayed poorer mental health literacy skills than females.
Gibbons et al. (2015) Beliefs and attitudes towards mental illness: an examination of the sex differences in mental health literacy in a community sample. PeerJ 3:e1004 https://doi.org/10.7717/peerj.1004
Catch, bycatch and discards of the Galapagos Marine Reserve small-scale handline fishery
Fisheries bycatch is a significant marine conservation issue as valuable fish are wasted and protected species harmed with potential negative ecological and socio-economic consequences. Even though there are indications that the small-scale handline fishery of the Galapagos Marine Reserve has a low selectivity, information on its bycatch has never been published. We used onboard monitoring and interview data to assess the bycatch of the Galapagos handline fishery by estimating the bycatch ratio, determining species compositions of landings and bycatch, identifying fishers’ reasons for discarding certain individuals, and revealing historical trends in the bycatch ratio. The estimated bycatch ratio as a function of biomass of 0.40 and a diverse species composition of target catch and bycatch confirmed the low selectivity of this fishery. Most individuals were not landed for economic motivations, either because species (77.4%) or sizes (17.7%) are unmarketable or for regulatory reasons (5.9%). We found that bycatch contributes to growth overfishing of some target species because they are discarded or used as bait before reaching their first maturity. Moreover, over half of interviewees perceived a historical decrease in bycatch ratios that was explained by a diversification of the target catch due to the reduction in abundance of the traditionally most important target species. As some target species show signs of overfishing and to date there are no specific regulations for the finfish fishery species in place, we recommend the implementation of a series of management measures to protect critical life stages of overexploited species and to improve the selectivity of the Galapagos handline fishery.
Zimmerhackel et al. (2015) Catch, bycatch and discards of the Galapagos Marine Reserve small-scale handline fishery. PeerJ 3:e995 https://doi.org/10.7717/peerj.995
Personality psychopathology, drug use and psychological symptoms in adolescents with substance use disorders and community controls
Substance use is a risk behavior that tends to increase during adolescence, a time when part of the personality is still in development. Traditionally, personality psychopathology has been measured in terms of categories, although dimensional models have demonstrated better consistency. This study aimed to analyze differences in personality profiles between adolescents with substance use disorders (SUD n = 74) and matched community controls (MCC n = 74) using the Personality Psychopathology Five (PSY-5) dimensional model. Additionally, we compared age at first drug use, level of drug use and internalizing and externalizing symptoms between the groups. In this study, the PSY-5 model has proved to be useful for differentiating specific personality disturbances in adolescents with SUD and community adolescents. The Disconstraint scale was particularly useful for discriminating adolescents with substance use problems and the Delinquent Attitudes facet offered the best differentiation.
Magallón-Neri et al. (2015) Personality psychopathology, drug use and psychological symptoms in adolescents with substance use disorders and community controls. PeerJ 3:e992 https://doi.org/10.7717/peerj.992
Research groups: How big should they be?
Understanding the relationship between scientific productivity and research group size is important for deciding how science should be funded. We have investigated the relationship between these variables in the life sciences in the United Kingdom using data from 398 principle investigators (PIs). We show that three measures of productivity, the number of publications, the impact factor of the journals in which papers are published and the number of citations, are all positively correlated to group size, although they all show a pattern of diminishing returns—doubling group size leads to less than a doubling in productivity. The relationships for the impact factor and the number of citations are extremely weak. Our analyses suggest that an increase in productivity will be achieved by funding more PIs with small research groups, unless the cost of employing post-docs and PhD students is less than 20% the cost of a PI. We also provide evidence that post-docs are more productive than PhD students both in terms of the number of papers they produce and where those papers are published.
Cook et al. (2015) Research groups: How big should they be?. PeerJ 3:e989 https://doi.org/10.7717/peerj.989
The taxonomy of a new parvicursorine alvarezsauroid specimen IVPP V20341 (Dinosauria: Theropoda) from the Upper Cretaceous Wulansuhai Formation of Bayan Mandahu, Inner Mongolia, China
A new parvicursorine alvarezsauroid theropod specimen IVPP V20341 from the Upper Cretaceous Wulansuhai Formation of Bayan Mandahu, Inner Mongolia, China is described. IVPP V20341 appears to be distinguishable amongst alvarezsauroids by possible cervical procoely and relatively larger semi-circular caudal neural canals, but these features are not proposed as autapomorphies because current knowledge of alvarezsauroid necks and tails remains sparse. IVPP V20341 is distinguishable from Linhenykus—the sole parvicursorine at Bayan Mandahu—by the location of the origination points of the anterior caudal transverse processes; in IVPP V20341 this is the anterodorsal corner of the centra, whereas in Linhenykus it is the posterior end of the prezygapophyses. A number of additional tentative differences between IVPP V20341 and Linhenykus are also identified, but cannot be confirmed until further details of anatomical variation along the neck and tail are revealed by future finds. Thus, following the study of IVPP V20341 there are still seven parvicursorine species from the Upper Cretaceous Gobi Basin, but future finds could increase this to eight species.
Pittman et al. (2015) The taxonomy of a new parvicursorine alvarezsauroid specimen IVPP V20341 (Dinosauria: Theropoda) from the Upper Cretaceous Wulansuhai Formation of Bayan Mandahu, Inner Mongolia, China. PeerJ 3:e986 https://doi.org/10.7717/peerj.986