Improving the reliability of model-based decision-making estimates in the two-stage decision task with reaction-times and drift-diffusion modeling

A well-established notion in cognitive neuroscience proposes that multiple brain systems contribute to choice behaviour. These include: (1) a model-free system that uses values cached from the outcome history of alternative actions, and (2) a model-based system that considers action outcomes and the transition structure of the environment. The widespread use of this distinction, across a range of applications, renders it important to index their distinct influences with high reliability. Here we consider the two-stage task, widely considered as a gold standard measure for the contribution of model-based and model-free systems to human choice. We tested the internal/temporal stability of measures from this task, including those estimated via an established computational model, as well as an extended model using drift-diffusion. Drift-diffusion modeling suggested that both choice in the first stage, and RTs in the second stage, are directly affected by a model-based/free trade-off parameter. Both parameter recovery and the stability of model-based estimates were poor but improved substantially when both choice and RT were used (compared to choice only), and when more trials (than conventionally used in research practice) were included in our analysis. The findings have implications for interpretation of past and future studies based on the use of the two-stage task, as well as for characterising the contribution of model-based processes to choice behaviour

In silico karyotyping of chromosomally polymorphic malaria mosquitoes in the Anopheles gambiae complex

Chromosomal inversion polymorphisms play an important role in adaptation to environmental heterogeneities. For mosquito species in the Anopheles gambiae complex that are significant vectors of human malaria, paracentric inversion polymorphisms are abundant and are associated with ecologically and epidemiologically important phenotypes. Improved understanding of these traits relies on determining mosquito karyotype, which currently depends upon laborious cytogenetic methods whose application is limited both by the requirement for specialized expertise and for properly preserved adult females at specific gonotrophic stages. To overcome this limitation, we developed sets of tag single nucleotide polymorphisms (SNPs) inside inversions whose biallelic genotype is strongly correlated with inversion genotype. We leveraged 1,347 fully sequenced An. gambiae and Anopheles coluzzii genomes in the Ag1000G database of natural variation. Beginning with principal components analysis (PCA) of population samples, applied to windows of the genome containing individual chromosomal rearrangements, we classified samples into three inversion genotypes, distinguishing homozygous inverted and homozygous uninverted groups by inclusion of the small subset of specimens in Ag1000G that are associated with cytogenetic metadata. We then assessed the correlation between candidate tag SNP genotypes and PCA-based inversion genotypes in our training sets, selecting those candidates with >80% agreement. Our initial tests both in held-back validation samples from Ag1000G and in data independent of Ag1000G suggest that when used for in silico inversion genotyping of sequenced mosquitoes, these tags perform better than traditional cytogenetics, even for specimens where only a small subset of the tag SNPs can be successfully ascertained

Interprofessional education for first year psychology students: career plans, perceived relevance and attitudes

Undergraduate psychology students have been largely excluded from interprofessional education (IPE) initiatives. In contrast to many health professions, undergraduate psychology students do not engage in work placements as part of their degree, and many enter careers outside the health care context. However, the collaborative skills gained through an IPE experience may well be beneficial to students who work in this wider context. This research examines whether undergraduate psychology students’ views of IPE vary according to their planned career directions, and if so, whether the perceived relevance of IPE mediates the relationships. A sample of 188 Australian university undergraduate psychology students completed an online questionnaire following completion of a first-year IPE health sciences program. Path analysis indicated that psychology students’ attitudes towards IPE are associated with both professional identification and practitioner orientation, fully mediated through the perceived relevance of IPE to future career and study plans. Stronger professional identification and practitioner orientation were associated with greater perceived relevance and more positive and less negative attitudes towards IPE. Placing a stronger emphasis on the generalizability of IP skills taught may increase students’ awareness of the relevance outside of the health context, reducing disengagement of students planning alternative careers

Evidence of widespread selection on standing variation in Europe at height-associated SNPs.

Strong signatures of positive selection at newly arising genetic variants are well documented in humans(1-8), but this form of selection may not be widespread in recent human evolution(9). Because many human traits are highly polygenic and partly determined by common, ancient genetic variation, an alternative model for rapid genetic adaptation has been proposed: weak selection acting on many pre-existing (standing) genetic variants, or polygenic adaptation(10-12). By studying height, a classic polygenic trait, we demonstrate the first human signature of widespread selection on standing variation. We show that frequencies of alleles associated with increased height, both at known loci and genome wide, are systematically elevated in Northern Europeans compared with Southern Europeans (P < 4.3 × 10(-4)). This pattern mirrors intra-European height differences and is not confounded by ancestry or other ascertainment biases. The systematic frequency differences are consistent with the presence of widespread weak selection (selection coefficients ∼10(-3)-10(-5) per allele) rather than genetic drift alone (P < 10(-15))

Euclid : Forecasts from redshift-space distortions and the Alcock-Paczynski test with cosmic voids

Euclid is poised to survey galaxies across a cosmological volume of unprecedented size, providing observations of more than a billion objects distributed over a third of the full sky. Approximately 20 million of these galaxies will have their spectroscopy available, allowing us to map the three-dimensional large-scale structure of the Universe in great detail. This paper investigates prospects for the detection of cosmic voids therein and the unique benefit they provide for cosmological studies. In particular, we study the imprints of dynamic (redshift-space) and geometric (Alcock-Paczynski) distortions of average void shapes and their constraining power on the growth of structure and cosmological distance ratios. To this end, we made use of the Flagship mock catalog, a state-of-the-art simulation of the data expected to be observed with Euclid. We arranged the data into four adjacent redshift bins, each of which contains about 11000 voids and we estimated the stacked void-galaxy cross-correlation function in every bin. Fitting a linear-theory model to the data, we obtained constraints on f/b and DMH, where f is the linear growth rate of density fluctuations, b the galaxy bias, D-M the comoving angular diameter distance, and H the Hubble rate. In addition, we marginalized over two nuisance parameters included in our model to account for unknown systematic effects in the analysis. With this approach, Euclid will be able to reach a relative precision of about 4% on measurements of f/b and 0.5% on DMH in each redshift bin. Better modeling or calibration of the nuisance parameters may further increase this precision to 1% and 0.4%, respectively. Our results show that the exploitation of cosmic voids in Euclid will provide competitive constraints on cosmology even as a stand-alone probe. For example, the equation-of-state parameter, w, for dark energy will be measured with a precision of about 10%, consistent with previous more approximate forecasts.Peer reviewe

The therapeutic alliance in psychotherapy for adolescent depression: Differences between treatment types and change over time

Although the alliance is usually considered a generic factor common to all therapies, there are theoretical reasons to suspect that it may develop differently in different types of therapies. Yet, in youth psychotherapy, little is known about this issue to date. This study investigated whether the mean strength of the alliance, as well as its trajectory over time, differed between three equally effective psychological treatments for adolescent depression. Data were drawn from the IMPACT study, a randomized controlled trial comparing cognitive-behavioral therapy (CBT) and short-term psychoanalytic psychotherapy (STPP) versus a brief psychosocial intervention (BPI) in the treatment of adolescent depression. Adolescents’ (N = 338) and therapists’ (n = 159) ratings of the alliance were collected using the Working Alliance Inventory short form at 6, 12, and 36 weeks after randomization. Data were analyzed using multilevel linear models. Results showed that adolescents’ and therapists’ mean alliance ratings differed between treatment types, being highest in CBT and lowest in the STPP at all time points. Mean therapists’ alliance ratings increased slightly over time in all arms, while mean adolescents’ ratings were stable over time in CBT and BPI but slightly increased in the STPP group. These findings suggest that the mean strength of the alliance differs between treatment type, and future research is required to pinpoint what factors contribute to these differences and their relationship with treatment outcomes

A longitudinal study of cattle productivity in intensive dairy farms in central Ethiopia

Ethiopia is witnessing an emergence of intensive urban dairy farming. The aims of this study were to capture cattle productivity parameters in selected intensive dairy farms in and around Addis Ababa (Central Ethiopia). The study is a pre-requisite and baseline for further economic analysis of diseases such as bovine tuberculosis (BTB) and to assess some of the current challenges faced by farm owners for optimal animal performances. Hence, a 3-year longitudinal observational study was conducted for the first time in Ethiopia, in 24 dairy farms with intensive husbandry, including a total of 1,705 dairy animals. Herd characteristics, animal movement, and productivity parameters (fertility, morbidity, mortality) were recorded in a herd-book. Whereas, half the farms saw their animals increase in number over the 3 years, 37.5% (mainly large farms) saw their herd size decrease. Offtakes accounted for 76.6% of all animal exits. One hundred and ninety (11.1%) animals died of natural causes. Highest mortality was observed in young stock (13.9%). Overall, diseases were the leading cause for death (57.5%). The majority of calves (69%) that died, did so within the first week of life. Mean calving interval (CI) was 483.2 days. Successful conception after artificial insemination (AI) was 66.1% with Addis Ababa and smaller farms faring worst. Mean time interval from calving to first service was 152 days. Date of birth to first service was 592.2 days and date of birth to first calving was 794.7 days. In conclusion, the study showed sub-optimal productivity performances in intensive dairy cattle and highlighted some of the current gaps and challenges in urban dairy productivity

The alliance–outcome association in the treatment of adolescent depression

A growing body of research has consistently demonstrated a relationship between alliance and treatment outcomes in youth psychotherapy. However, past research often suffered methodological issues that prevented detailed investigation of temporal relationships between alliance and symptomatology. The current study explored the directions of effect between alliance and outcome by examining the associations between early alliance and subsequent outcome while controlling for patients’ baseline severity and prior symptom change. It also examined potential moderators of this association. Data were drawn from the IMPACT study, a randomized controlled trial comparing cognitive-behavioural therapy (CBT) and short-term psychoanalytic psychotherapy (STPP) versus a brief psychosocial intervention (BPI) in the treatment of adolescent depression. Adolescents (N=224) and therapist (n=139) rated the alliance 6 weeks after randomization. Depression severity and overall psychopathology were assessed at baseline, 6, 12, 36, 52 and 86 weeks after randomization. Patients’ age, gender, baseline depression severity, conduct disorder symptoms and treatment type were examined as potential moderators of the alliance-outcome association. Data were analysed using multilevel models. Findings suggested that higher early alliance ratings were associated with subsequent symptom reduction, even after controlling for prior symptom change and baseline severity. There was evidence that the strength of this association was strongest in CBT patients, weaker in STPP, and statistically indistinguishable from zero in BPI. These findings suggest that early therapeutic alliance with adolescents may influence subsequent outcome independent of prior symptom change and initial severity but that the effect of the alliance on outcome might vary across treatment types

The factor structure of the Working Alliance Inventory Short-form in youth psychotherapy: an empirical investigation

Objective: The Working Alliance Inventory short form (WAI-S) is one of the most commonly used alliance measures with adolescents. Yet, its factor structure has received minimal attention in the youth alliance literature. This study investigated the factor structure of the WAI-S in psychotherapy for adolescent depression and explored its measurement invariance across time, therapeutic approaches and patients’ and therapists’ perspectives. The existence of method effects associated with the negatively worded items of the scale was also assessed. Method: The setting of this study is the IMPACT trial, a randomised controlled trial assessing the effects of three therapeutic interventions in the treatment of adolescent depression. The WAI-S was completed at 6, 12 and 36 weeks after randomisation by 338 adolescents and 159 therapists. Data were analysed using confirmatory factor analysis. Results: The hypothesised Bond-Task-Goal alliance structure was not supported and a general, one-factor model was found to be more psychometrically valid. The existence of a method effect and measurement invariance across time and treatment arms were also found. Conclusions: While the distinction between the specific alliance dimensions is conceptually and clinically interesting, at an empirical level the alliance features of the WAI-S in youth psychotherapy remain strongly intercorrelated