Object Location Memory Error in Virtual and Real Environments

We aim to further explore the transfer of spatial knowledge from virtual to real spaces. Based on previous research on spatial memory in immersive virtual reality (VR) we ran a study that looked at the effect of three locomotion techniques (joystick, pointing-and-teleporting and walking-in-place) on object location learning and recall. Participants were asked to learn the location of a virtual object in a virtual environment (VE). After a short period of time they were asked to recall the location by placing a real version of the object in the real-world equivalent environment. Results indicate that the average placement error, or distance between original and recalled object location, is approximately 20cm for all locomotion technique conditions. This result is similar to the outcome of a previous study on spatial memory in VEs that used real walking. We report this unexpected finding and suggest further work on spatial memory in VR by recommending the replication of this study in different environments and using objects with a wider diversity of properties, including varying sizes and shapes

A Comparison of Virtual and Physical Training Transfer of Bimanual Assembly Tasks

As we explore the use of consumer virtual reality technology for training applications, there is a need to evaluate its validity compared to more traditional training formats. In this paper, we present a study that compares the effectiveness of virtual training and physical training for teaching a bimanual assembly task. In a between-subjects experiment, 60 participants were trained to solve three 3D burr puzzles in one of six conditions comprised of virtual and physical training elements. In the four physical conditions, training was delivered via paper- and video-based instructions, with or without the physical puzzles to practice with. In the two virtual conditions, participants learnt to assemble the puzzles in an interactive virtual environment, with or without 3D animations showing the assembly process. After training, we conducted immediate tests in which participants were asked to solve a physical version of the puzzles. We measured performance through success rates and assembly completion testing times. We also measured training times as well as subjective ratings on several aspects of the experience. Our results show that the performance of virtually trained participants was promising. A statistically significant difference was not found between virtual training with animated instructions and the best performing physical condition (in which physical blocks were available during training) for the last and most complex puzzle in terms of success rates and testing times. Performance in retention tests two weeks after training was generally not as good as expected for all experimental conditions. We discuss the implications of the results and highlight the validity of virtual reality systems in training

Prenatal exposure to NO2 and ultrasound measures of fetal growth in the Spanish INMA cohort

__Background:__ Air pollution exposure during pregnancy has been associated with impaired fetal growth. However, few studies have measured fetal biometry longitudinally, remaining unclear as to whether there are windows of special vulnerability. __Objective:__ The aim was to investigate the impact of nitrogen dioxide (NO2) exposure on fetal and neonatal biometry in the Spanish INMA study. Methods: Biparietal diameter (BPD), femur length (FL), abdominal circumference (AC), and estimated fetal weight (EFW) were evaluated for up to 2,478 fetuses in each trimester of pregnancy. Size at 12, 20, and 34 weeks of gestation and growth between these points, as well as anthropometry at birth, were assessed by SD scores derived using cohort-specific growth curves. Temporally adjusted land-use regression was used to estimate exposure to NO2 at home addresses for up to 2,415 fetuses. Associations were investigated by linear regression in each cohort and subsequent meta-analysis. __Results:__ A 10-μg/m3 increase in average exposure to NO2 during weeks 0-12 was associated with reduced growth at weeks 0-12 in AC (-2.1%; 95% CI: -3.7, -0.6) and EFW (-1.6%; 95% CI: -3.0, -0.3). The same exposure was inversely associated with reduced growth at weeks 20-34 in BPD (-2.6%; 95% CI: -3.9, -1.2), AC (-1.8%; 95% CI: -3.3, -0.2), and EFW (-2.1%; 95% CI: -3.7, -0.2). A less consistent pattern of association was observed for FL. The negative association of this exposure with BPD and EFW was significantly stronger in smoking versus nonsmoking mothers. __Conclusi

Contrast in Edge Vegetation Structure Modifies the Predation Risk of Natural Ground Nests in an Agricultural Landscape

Nest predation risk generally increases nearer forest-field edges in agricultural landscapes. However, few studies test whether differences in edge contrast (i.e. hard versus soft edges based on vegetation structure and height) affect edge-related predation patterns and if such patterns are related to changes in nest conspicuousness between incubation and nestling feeding. Using data on 923 nesting attempts we analyse factors influencing nest predation risk at different edge types in an agricultural landscape of a ground-cavity breeding bird species, the Northern Wheatear (Oenanthe oenanthe). As for many other bird species, nest predation is a major determinant of reproductive success in this migratory passerine. Nest predation risk was higher closer to woodland and crop field edges, but only when these were hard edges in terms of ground vegetation structure (clear contrast between tall vs short ground vegetation). No such edge effect was observed at soft edges where adjacent habitats had tall ground vegetation (crop, ungrazed grassland). This edge effect on nest predation risk was evident during the incubation stage but not the nestling feeding stage. Since wheatear nests are depredated by ground-living animals our results demonstrate: (i) that edge effects depend on edge contrast, (ii) that edge-related nest predation patterns vary across the breeding period probably resulting from changes in parental activity at the nest between the incubation and nestling feeding stage. Edge effects should be put in the context of the nest predator community as illustrated by the elevated nest predation risk at hard but not soft habitat edges when an edge is defined in terms of ground vegetation. These results thus can potentially explain previously observed variations in edge-related nest predation risk

Understanding the relationship between the proteus effect, immersion, and gender among world of Warcraft players: an empirical survey study

Online gaming is part of contemporary life, with a range of influences on gamer's behaviour. The convergence and alignment of an individual's attitude and behaviour with features and characteristics of their in-game representation (i.e. their avatar), is conceptualised as the 'Proteus effect' (PE). In the massively multiplayer online role-playing game World of Warcraft (WoW), the Draenei ('exiled ones') are one type of in-game character faction. In the present study, the interplay between choosing the class of Draenei, experiencing game-related immersion, along with the gamer's biological gender was examined in relation to PE behaviours among 404 WoW gamers (males = 299; 74%; females = 104; 26%). Participants completed the Proteus Effect Scale and the Immersion sub-scale of the User-Avatar Questionnaire. A hierarchical regression analysis indicated a significant positive association between immersion and PE behaviours. Furthermore, mediation and moderated mediation analyses suggested that being a Draenei was positively associated with the level of game-related immersion, which in turn associated to higher PE behaviours offline, independent of participants' gender. Results indicate that gamers who are more immersed within the gaming world tend to exhibit elevated PE behaviours. Moreover, being a Draenei in WoW appeared to relate with higher game-immersion experiences, which resulted in higher PE behaviours offline

Epidemiology and pathogenesis of maternal-fetal transmission of Trypanosoma cruzi and a case for vaccine development against congenital Chagas disease

Trypanos o ma cruzi (T. cruzi or Tc) is the causative agent of Chagas disease (CD). It is common for patients to suffer from non-specific symptoms or be clinically asymptomatic with acute and chronic conditions acquired through various routes of transmission. The expecting women and their fetuses are vulnerable to congenital transmission of Tc. Pregnant women face formidable health challenges because the frontline antiparasitic drugs, benznidazole and nifurtimox, are contraindicated during pregnancy. However, it is worthwhile to highlight that newborns can be cured if they are diagnosed and given treatment in a timely manner. In this review, we discuss the pathogenesis of maternal-fetal transmission of Tc and provide a justification for the investment in the development of vaccines against congenital CD.Fil: Rios, Lizette. University of Texas Medical Branch; Estados UnidosFil: Campos, Emiliano Emanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; ArgentinaFil: Menon, Ramkumar. University of Texas Medical Branch; Estados UnidosFil: Zago, María Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; ArgentinaFil: Garg, Nisha J.. University of Texas Medical Branch; Estados Unido

Exploration of Shared Genetic Architecture Between Subcortical Brain Volumes and Anorexia Nervosa

In MRI scans of patients with anorexia nervosa (AN), reductions in brain volume are often apparent. However, it is unknown whether such brain abnormalities are influenced by genetic determinants that partially overlap with those underlying AN. Here, we used a battery of methods (LD score regression, genetic risk scores, sign test, SNP effect concordance analysis, and Mendelian randomization) to investigate the genetic covariation between subcortical brain volumes and risk for AN based on summary measures retrieved from genome-wide association studies of regional brain volumes (ENIGMA consortium, n = 13,170) and genetic risk for AN (PGC-ED consortium, n = 14,477). Genetic correlations ranged from − 0.10 to 0.23 (all p > 0.05). There were some signs of an inverse concordance between greater thalamus volume and risk for AN (permuted p = 0.009, 95% CI: [0.005, 0.017]). A genetic variant in the vicinity of ZW10, a gene involved in cell division, and neurotransmitter and immune system relevant genes, in particular DRD2, was significantly associated with AN only after conditioning on its association with caudate volume (pFDR = 0.025). Another genetic variant linked to LRRC4C, important in axonal and synaptic development, reached significance after conditioning on hippocampal volume (pFDR = 0.021). In this comprehensive set of analyses and based on the largest available sample sizes to date, there was weak evidence for associations between risk for AN and risk for abnormal subcortical brain volumes at a global level (that is, common variant genetic architecture), but suggestive evidence for effects of single genetic markers. Highly powered multimodal brain- and disorder-related genome-wide studies are needed to further dissect the shared genetic influences on brain structure and risk for AN