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Effects of Altered Haptic Feedback Gain Upon Balance Are Explained by Sensory Conflict Estimation
No full textLightly touching a solid object reduces postural sway. Here, we determine the effect of artificially modifying haptic feedback for balance. Participants stood with their eyes closed, lightly gripping a manipulandum that moved synchronously with body sway to systematically enhance or attenuate feedback gain between +2 and −2, corresponding to motion in the same or opposite direction to the body, respectively. This intervention had a systematic effect on postural sway, which exhibited an asymmetric u‐shape function with respect to haptic feedback gain. Sway was minimal around zero gain, corresponding to a static object. Sway increased slightly at gains below −0.25 but increased greatly at gains above +0.25. At +2, it was approximately double that of a no‐touch condition. Mean interaction force between the hand and manipulandum remained < 0.9 N throughout, although it increased slightly at extreme gains. Cross‐correlations between hand force and trunk position were highest during conditions of least sway, suggesting that higher quality haptic feedback is associated with greater sway reduction. We successfully replicated the sway behaviour using a feedback control model that attenuated haptic feedback signals when the discrepancy between haptic and proprioceptive signals reached a threshold. Our findings suggests the CNS can utilise augmented haptic feedback for balance, but only with relatively small changes to natural feedback gain. In healthy volunteers, it offers minimal benefit over a static object. Haptic feedback is therefore optimal when motion is physiologically realistic and subtle enough to be misinterpreted as self‐motion.publishe
Prickly postglacial pioneers: freshwater plankton community composition influences fatty acid desaturase (FADS2) copy number in southern Greenland threespine sticklebacks
No full textThe adaptation of marine fish to freshwater environments includes prodigious examples of rapid evolution.Given the scarcity of ω-3 long-chain polyunsaturated fatty acids (LC-PUFA) in freshwater, we expect selection to be strong on fish transitioning to freshwater habitats and yet the underlying ecological causes of genomic and phenotypic differentiation are poorly understood for traits associated with lipid content and composition. Threespine stickleback Gasterosteus aculeatus have repeatedly colonized, and adapted to, freshwater habitats across the Northern Hemisphere. These freshwater populations often show elevated copy number of the fatty acid desaturase 2 gene (FADS2), which increases the biosynthetic capacity of LC-PUFA. The starkly lower content of LC-PUFA in freshwater compared to marine prey, especially docosahexaenoic acid (DHA), likely imposes strong positive selection on freshwater fish for either increased biosynthesis or greater dietary acquisition of LC-PUFA. The recently colonized and relatively undisturbed threespine stickleback populations in postglacial coastal lakes of southern Greenland offer an exceptional opportunity to study how variation in the copy number of FADS2 is related to abiotic and biotic conditions of lakes and their morphometry. As expected, given its position on the stickleback X chromosome, we found strong sexual dimorphism in FADS2 copy number in all populations (19 freshwater, 1 marine and 1 brackish), and an increased dimorphism in some freshwater populations. We also found that FADS2 copy number was negatively correlated, for both males and females, with the abundance of copepods, which are a DHA-rich food source in the zooplankton community. Overall, our results suggest that the prey community context of lakes might influence the process of metabolic adaptation of marine fish colonizing freshwater ecosystems.publishe
A Sparse Approximate Factor Model for High-Dimensional Covariance Matrix Estimation and Portfolio Selection
No full textWe propose a novel estimation approach for the covariance matrix based on the l1-regularized approximate factor model (AFM). Our sparse approximate factor (SAF) covariance estimator allows for the existence of weak factors and hence relaxes the pervasiveness assumption generally adopted for the standard AFM. We prove the consistency of the covariance matrix estimator under the Frobenius norm as well as the consistency of the factor loadings and the factors. Our Monte Carlo simulations reveal that the SAF covariance estimator has superior properties in finite samples for low and high dimensions and different designs of the covariance matrix. Moreover, in an out-of-sample portfolio forecasting application, the estimator uniformly outperforms alternative portfolio strategies based on alternative covariance estimation approaches and modeling strategies including the 1/N-strategy.publishe
Psychoneural reduction revised : The case of suicidality in bipolar disorder
No full textThis paper uses suicidality in bipolar disorder (BD) to illustrate that multidimensional frameworks account for complex phenomena with cognitive, psychological, socioenvironmental and physiological components better than their reductionist counterparts. We challenge level‐based reductionist models that regard a particular dimension as fundamental. To comprehensively understand complex psychiatric phenomena, multidimensional models that acknowledge the heterogeneity of aetiological factors, rather than homogenising them under a single dimension, must be utilised. Multidimensional models allow a better understanding of the individual context under which a psychiatric phenomenon arises, and the interrelationships between its different aetiological dimensions. Suicidality in BD is used as a case study because it particularly highlights the interplay between biological, psychological, sociocultural and experiential factors. The multidimensional nature of suicidality is reflected by the heterogeneous strategies by which it is managed. Although similar to suicidality in other contexts, in BD suicidality has distinctive structural characteristics that emphasise its multidimensionality. Consequently, investigating suicidality in BD yields claims generalisable to suicidality as a whole alongside novel insights on BD‐specific features. For instance, suicidality in BD has physiological causal factors, e.g., genetic predisposition and aggravation by symptomatic periods. However, its other features underscore the causal roles of cognitions. In persons with BD, suicidality can persist beyond depression and is sometimes experienced during mania, possibly due to suicidal ideation persisting beyond symptomatic periods. This indicates the need to account for cognitive or psychological causal factors. Models of suicidality in BD typically adopt a non‐level‐based, non‐reductionist approach, reflected in the diverse clinical strategies for managing suicidality in BD.publishe
Cortical representation of novel tool use: Understanding the neural basis of mechanical problem solving
No full textIntroduction
Using tools effectively is a fundamental human ability. Besides the proper recall of semantic knowledge, the application of mechanical problem solving strategies allows one to execute tool-related tasks properly. Past fMRI studies have shown a mainly left-lateralized network, including ventral, ventro-dorsal, and dorso-dorsal streams while using familiar tools with access to semantic information. However, to what degree the network is recruited when applying mechanical problem solving strategies to handle novel tools remains unclear.
Methods
An event-related fMRI study including 22 participants was conducted. During scanning, participants had to manipulate novel tools, the function of which they could infer by mechanical problem solving. Brain activity was measured during actual novel tool use and selection, both during the planning and execution phase.
Results
Similar brain activation during tool use and tool selection could be observed, ranging from left-hemispheric inferior parietal to frontal regions in the ventro-dorsal stream with lack of ventral activation. Task-specific activations were more pronounced during the planning phases.
Discussion
During mechanical problem solving brain activation is more pronounced in the ventro-dorsal stream, where mechanical understanding and motor control need to be integrated. Similar networks recruited during tool selection compared to tool use trials reflect mental simulation strategies used to determine the appropriate tool-recipient fit. The ventral stream, linked to the recall of semantic knowledge, plays a subordinate role during this task and a stronger involvement of anterior regions reflect the relevance of the frontal lobe contributing to mechanical problem solving.publishe
What the new loss and damage fund needs for public approval : choice experimental evidence from Austria
No full textThe severity of extreme weather events is increasing due to climate change. While industrialized nations have historically contributed the most to greenhouse gas emissions and are thus considered the primary polluters, the adverse impacts of climate change are disproportionately felt in low-income countries with limited capacity to cope. These regions are generally less resilient to extreme weather, resulting in significant damage. Many vulnerable countries lack the resources to manage these losses independently, necessitating international financial support. For over 30 years, the allocation of these costs has been a central issue at UN climate conferences. At COP 27 and COP 28, an international fund was established to address climate-induced losses and damages. However, key details regarding payment obligations and the distribution of funds remain unresolved. Securing consistent funding requires public approval in donor countries. To understand public preferences, we conducted a representative choice experiment in Austria exploring various financing options for such a fund. Our findings suggest that public support is higher if contributions are based on principles of responsibility rather than voluntary donations, with a preference for disaster relief payments. Additionally, respondents favored a maximum monthly contribution of 30 € per capita and prioritized funding for slow-onset events over rapid-onset events.publishe
Losing control : Prefrontal emotion regulation relates to symptom severity and predicts treatment-related symptom change in adolescent girls with conduct disorder
No full textBackground: Emotion regulation skills are linked to corticolimbic brain activity (e.g., dorsolateral prefrontal cortex (dlPFC) and limbic regions) and enable an individual to control their emotional experiences thus allowing healthy social functioning. Disruptions in emotion regulation skills are reported in neuropsychiatric disorders, including conduct disorder or oppositional defiant disorder (CD/ODD). Clinically recognized means to ameliorate emotion regulation deficits observed in CD/ODD include cognitive or dialectical behavioral skills therapy as implemented in the START-NOW program. However, the role of emotion regulation and its neural substrates in symptom severity and prognosis following treatment of adolescent CD/ODD has yet to be investigated.
Methods: Cross-sectional data including fMRI responses during emotion regulation (N=114; average age=15years), repeated-measures assessments of symptom severity (pre-, post-treatment, long-term follow-up), and fMRI data collected prior to and following the START-NOW randomized controlled trial (n=44) for female adolescents with CD/ODD were analyzed using group comparisons and multiple regression.
Results: First, behavioral and neural correlates of emotion regulation are disrupted in female adolescents with CD/ODD. Second, ODD symptom severity is negatively associated with dlPFC/precentral gyrus activity during regulation. Third, treatment-related symptom changes are predicted by pre-treatment ODD symptom severity and regulatory dlPFC/precentral activity. Additionally, pre-treatment dlPFC/precentral activity and ODD symptom severity predict long-term reductions in symptom severity following treatment for those participants that received the START NOW treatment.
Conclusion: Our findings demonstrate the important role that emotion regulation skills play in the characteristics of CD/ODD and show that regulatory dlPFC/precentral activity is positively associated with treatment response in female adolescents with CD/ODD.publishe
Substantive Representation : Explaining the Adoption of Indigenous Rights Legislation in Latin America
No full textIndigenous peoples belong to the most underprivileged groups worldwide. To address this situation, countries in Latin America and beyond increasingly recognize Indigenous rights constitutionally. However, these constitutional rights are not implemented equally everywhere. This could relate to the corresponding ordinary law—or lack thereof. Here I ask, under which conditions are Indigenous peoples represented in ordinary legislation? To answer this question, I collected the original INDILEX dataset on the status of Indigenous peoples and their rights in the legislation of sixteen Latin American countries (1979–2018). Building on the political representation literature, I contrast descriptive representation with political allies, social movements, and favorable context factors as determinants of the substantive representation of Indigenous peoples. The analysis shows that leftist presidents and a broad constitutional mandate are key predictors of Indigenous rights legislation. The role of Indigenous civil society and democracy depends on the time frame and operationalization choice.publishe
Breaking Barriers? : Social Inequality in Pathways to Higher Education Between General and Vocational Schools in Germany
No full textPathways to higher education through vocational upper secondary schools (VUSSs) are intended to increase permeability. However, in both VUSSs and general upper secondary schools (GUSSs), participation is socially selective. This article examined differences between GUSS and VUSS students in (a) the attainment of a higher education entrance qualification (HEEQ) and (b) the subsequent transition to higher education. Taking entry selectivity into account, we analysed the extent to which inequalities between GUSS and VUSS in both outcomes could be explained by differences in school achievement and educational considerations—namely, cost–benefit perceptions, expected success, and status maintenance motives. Using data from the German National Educational Panel Study (NEPS; Starting Cohort 4), we selected a sample of individuals who entered upper secondary education in either VUSS or GUSS ( = 5032). Two binary dependent variables were used to indicate (a) the successful attainment of an HEEQ and (b) the subsequent transition to higher education (as opposed to vocational education and training). The results from logit models indicated that VUSS students were significantly less likely to obtain an HEEQ and progress to higher education. This association was smaller but still persistent when controlling for entry selection, school achievement, and educational considerations (AMEHEEQ = −0.047, AMEtransition = −0.150). However, when intake selection was considered in the logit models, school achievement and educational considerations during upper secondary education were insignificant in explaining why VUSS students were less likely than GUSS students to obtain an HEEQ and enter higher education.publishe
Rapid-scan electron paramagnetic resonance spectroscopy of nitroxide based spin systems
No full textRapid-scan (RS) electron paramagnetic resonance (EPR) spectroscopy combined with site-directed spin-labeling (SDSL) is a powerful tool for investigating fast kinetics on biologically relevant timescales. This article provides an overview of the technique, highlighting the utility of nitroxide-based spin-labels and probes. Recent technical and methodological progress demonstrating the applicability of RS EPR is illustrated through examples in the field of chemical biology.publishe