Auxin-induced SCFTIR1-Aux/IAA interaction involves stable modification of the SCFTIR1 complex

The plant hormone auxin can regulate gene expression by destabilizing members of the Aux/IAA family of transcriptional repressors. Auxin-induced Aux/IAA degradation requires the protein-ubiquitin ligase SCFTIR1, with auxin acting to enhance the interaction between the Aux/IAAs and SCIFTIR1. SKP1, Cullin, and an F-box-containing protein (SCF)-mediated degradation is an important component of many eukaryotic signaling pathways. In all known cases to date, the interaction between the targets and their cognate SCFs is regulated by signal-induced modification of the target. The mechanism by which auxin promotes the interaction between SCFTIR1 and Aux/IAAs is not understood, but current hypotheses propose auxin-induced phosphorylation, hydroxylation, or proline isomerization of the Aux/IAAs. We found no evidence to support these hypotheses or indeed that auxin induces any stable modification of Aux/IAAs to increase their affinity for SCFTIR1. Instead, we present data suggesting that auxin promotes the SCIFTIR1-Aux/IAA interaction by affecting the SCIF component, TIR1, or proteins tightly associated with it

Network structure and dynamics of effective models of non-equilibrium quantum transport

Across all scales of the physical world, dynamical systems can often be usefully represented as abstract networks that encode the system's units and inter-unit interactions. Understanding how physical rules shape the topological structure of those networks can clarify a system's function and enhance our ability to design, guide, or control its behavior. In the emerging area of quantum network science, a key challenge lies in distinguishing between the topological properties that reflect a system's underlying physics and those that reflect the assumptions of the employed conceptual model. To elucidate and address this challenge, we study networks that represent non-equilibrium quantum-electronic transport through quantum antidot devices -- an example of an open, mesoscopic quantum system. The network representations correspond to two different models of internal antidot states: a single-particle, non-interacting model and an effective model for collective excitations including Coulomb interactions. In these networks, nodes represent accessible energy states and edges represent allowed transitions. We find that both models reflect spin conservation rules in the network topology through bipartiteness and the presence of only even-length cycles. The models diverge, however, in the minimum length of cycle basis elements, in a manner that depends on whether electrons are considered to be distinguishable. Furthermore, the two models reflect spin-conserving relaxation effects differently, as evident in both the degree distribution and the cycle-basis length distribution. Collectively, these observations serve to elucidate the relationship between network structure and physical constraints in quantum-mechanical models. More generally, our approach underscores the utility of network science in understanding the dynamics and control of quantum systems.Comment: 37 pages, including supplementary materia

Using virtual reality to assess and promote transfer of memory training in older adults with memory complaints: A randomized controlled trial

In this proof-of-concept study, we assessed the potential for immersive virtual reality (VR) to measure transfer following strategic memory training, and whether efficacy and transfer are increased when training is complemented by practice in an immersive virtual environment. Forty older adults with subjective memory complaints were trained with the method of loci. They were randomized to either a condition where they practiced the strategy in VR (n = 20) or a control condition where they were familiarized with VR using a non-memory task (n = 20). Training efficacy was measured with word recall, and transfer of the training benefit was measured with a recall task completed in two VR tasks (primary outcomes) as well as a self-report memory questionnaire (secondary outcomes). Testing was administered before (PRE), midway (POST 3), and after (POST 6) training. Participants improved their scores on word recall. Regarding transfer measures, participants improved their performance in the two VR recall tasks but not on the self-report memory questionnaire. No significant group effect was observed. Improvement was found when comparing PRE to POST 3 with no further improvement at POST 6. Thus, strategic memory training improved the memory of seniors with memory complaints on word recall and a transfer task relying on a VR scenario that resembles real-life. However, no evidence supporting an increase in transfer effects was found when enriching training with VR memory exercises

Intrinsically motivated graph exploration using network theories of human curiosity

Intrinsically motivated exploration has proven useful for reinforcement learning, even without additional extrinsic rewards. When the environment is naturally represented as a graph, how to guide exploration best remains an open question. In this work, we propose a novel approach for exploring graph-structured data motivated by two theories of human curiosity: the information gap theory and the compression progress theory. The theories view curiosity as an intrinsic motivation to optimize for topological features of subgraphs induced by the visited nodes in the environment. We use these proposed features as rewards for graph neural-network-based reinforcement learning. On multiple classes of synthetically generated graphs, we find that trained agents generalize to larger environments and to longer exploratory walks than are seen during training. Our method computes more efficiently than the greedy evaluation of the relevant topological properties. The proposed intrinsic motivations bear particular relevance for recommender systems. We demonstrate that curiosity-based recommendations are more predictive of human behavior than PageRank centrality for several real-world graph datasets, including MovieLens, Amazon Books, and Wikispeedia.Comment: 14 pages, 5 figures in main text, and 15 pages, 8 figures in supplemen

Access to Indigenous and allopathic medicines: A systematic review of barriers and facilitators

Background: Globally, Indigenous peoples are the victims of social inequalities in health. Their state of health is much lower than the health of the general population. Colonialism, living conditions and access to care are the main determinants of observed health conditions. The scientific objective of this systematic literature review is to study the facilitators and barriers to access healthcare for both, traditional and allopathic medicines. Methods: An inclusive search of electronic databases (e.g ProQuest, Ovid, Medline, CINAHL PLUS, Cochrane Library, ApaPsyNet, PsyINFO and Sociological Abstracts databases) of the past 20 years was performed. We retained studies discussing (1) traditional medicine (TM) or allopathic medicine (AM) or both and occurring (2) within Indigenous population worldwide. We made no distinction between research carried out in rural as opposed to urban areas. Results: A total of 45 studies published between 1996 and 2016 met our inclusion criteria and this speaks to the high interest and contemporary pertinence of accessing both systems of healthcare for Indigenous populations worldwide. Our thematic analysis enabled us to group barriers and facilitators into five categories, namely related to personal, relational, cultural, structural and policy components. As far as barriers and facilitators are concerned, the category that encompasses the most themes is the structural category. Conclusions: Mutual respect, trust and understanding of each other’s modalities is essential to offer the best healthcare options from both AM and TM to Indigenous peoples and hence pave the way to reducing health inequities. Wellness and strength-based approaches must also be favoured

Access to Indigenous and allopathic medicines: A systematic review of barriers and facilitators

Background: Globally, Indigenous peoples are the victims of social inequalities in health. Their state of health is much lower than the health of the general population. Colonialism, living conditions and access to care are the main determinants of observed health conditions. The scientific objective of this systematic literature review is to study the facilitators and barriers to access healthcare for both, traditional and allopathic medicines. Methods: An inclusive search of electronic databases (e.g ProQuest, Ovid, Medline, CINAHL PLUS, Cochrane Library, ApaPsyNet, PsyINFO and Sociological Abstracts databases) of the past 20 years was performed. We retained studies discussing (1) traditional medicine (TM) or allopathic medicine (AM) or both and occurring (2) within Indigenous population worldwide. We made no distinction between research carried out in rural as opposed to urban areas. Results: A total of 45 studies published between 1996 and 2016 met our inclusion criteria and this speaks to the high interest and contemporary pertinence of accessing both systems of healthcare for Indigenous populations worldwide. Our thematic analysis enabled us to group barriers and facilitators into five categories, namely related to personal, relational, cultural, structural and policy components. As far as barriers and facilitators are concerned, the category that encompasses the most themes is the structural category. Conclusions: Mutual respect, trust and understanding of each other’s modalities is essential to offer the best healthcare options from both AM and TM to Indigenous peoples and hence pave the way to reducing health inequities. Wellness and strength-based approaches must also be favoured

Activation changes induced by cognitive training are consistent with improved cognitive reserve in older adults with subjective cognitive decline

Abtract Functional magnetic resonance imaging (fMRI) was used to assess the effect of cognitive training on brain activation as a function of the learning phase and level of education. Forty older adults with subjective cognitive decline (SCD) received 6 1-hour memory training sessions with the method of loci. Brain imaging (N = 29) was measured during word list encoding and retrieval before training (PRE), after 3 training sessions (POST3), and after 6 training sessions (POST6). Participants showed increased activation of the left inferior pre-frontal gyrus from PRE to POST6 during encoding and reduced bilateral frontostriatal activation from PRE to POST3 during retrieval, regardless of education. Activation changes from PRE to POST3 varied as a function of education in 2 regions of the right temporal lobe: participants with lower education showed increased activation, while those with higher education showed decreased activation. These regions were initially less active in people with lower education. Results suggest a strategic shift in people with lower education and expertise building in those with higher education, along with a restoration of initial education-related differences

Laboratory demonstration of the triple-grating vector vortex coronagraph

The future Habitable Worlds Observatory aims to characterize the atmospheres of rocky exoplanets around solar-type stars. The vector vortex coronagraph (VVC) is a main candidate to reach the required contrast of $10^{-10}$. However, the VVC requires polarization filtering and every observing band requires a different VVC. The triple-grating vector vortex coronagraph (tgVVC) aims to mitigate these limitations by combining multiple gratings that minimize the polarization leakage over a large spectral bandwidth. In this paper, we present laboratory results of a tgVVC prototype using the In-Air Coronagraphic Testbed (IACT) facility at NASA's Jet Propulsion Laboratory and the Space Coronagraph Optical Bench (SCoOB) at the University of Arizona Space Astrophysics Lab (UASAL). We study the coronagraphic performance with polarization filtering at 633 nm and reach a similar average contrast of $2 \times 10^{-8}$ between 3-18 $\lambda/D$ at the IACT, and $6 \times 10^{-8}$ between 3-14 $\lambda/D$ at SCoOB. We explore the limitations of the tgVVC by comparing the testbed results. We report on other manufacturing errors and ways to mitigate their impact.Comment: 9 pages, 5 figures, SPIE Optics + Photonics - Techniques and Instrumentation for Detection of Exoplanets X