Using Augmented Reality as a Tool for Distance Learning of VSEPR Theory

Distance learning poses challenges in most academic settings, especially at the undergraduate laboratory level. Improving this mode of learning diminishes the impact of current events on young scientists’ development of foundational laboratory concepts. Our work explores the use of augmented reality (AR) in a laboratory setting. We developed a completely virtual valence shell electron pair repulsion (VSEPR) theory lab activity consistent with the goals of Keck Science Department’s Introduction to Chemistry course’s in-person VSEPR lab activity. We were able to maintain a hands-on learning experience for students while using a tool many students already own: an iPhone as an alternative to model kits typically used for this lesson. Evaluating the efficacy of the AR lab activity was done in the Fall 2020 semester with Keck Science Department’s CHEM14 class. I used a series of post-lab surveys, for instructors and students, to determine the efficacy of our approach and gauge students’ experience with the technology. Ultimately, instructors and students found the lab activity helpful and felt AR was the most helpful in mastering VSEPR theory

Structural Agnostic Modeling: Adversarial Learning of Causal Graphs

A new causal discovery method, Structural Agnostic Modeling (SAM), is presented in this paper. Leveraging both conditional independencies and distributional asymmetries in the data, SAM aims at recovering full causal models from continuous observational data along a multivariate non-parametric setting. The approach is based on a game between $d$ players estimating each variable distribution conditionally to the others as a neural net, and an adversary aimed at discriminating the overall joint conditional distribution, and that of the original data. An original learning criterion combining distribution estimation, sparsity and acyclicity constraints is used to enforce the end-to-end optimization of the graph structure and parameters through stochastic gradient descent. Besides the theoretical analysis of the approach in the large sample limit, SAM is extensively experimentally validated on synthetic and real data

Past, present and future environmental footprint of the Danish wind turbine fleet with LCA_WIND_DK, an online interactive platform

International audienceRenewable energy systems are promoted and developed notably due to their low environmental footprint. Fleet-wide robust environmental assessments are needed to drive the sustainable transition of energy systems worldwide. This study introduces a tailored comprehensive impact assessment methodology for fleets of renewable energy systems based on Life Cycle Analysis and its application to Danish wind turbines fleet through an online platform LCA_WIND_DK (viewer.webservice-energy.org/lca-wind-dk/). This platform enables to visualize environmental performances of wind turbines in Denmark and their temporal evolution. The fleet is known in detail from 1980 to 2016 and projected from 2017 to 2030 based on national objectives for onshore/offshore capacity and pre-approved offshore projects. Each turbine's future electricity production is estimated from its power curve and geo-localized wind time-series. More than 10,000 cradle-to-grave life cycle inventories are generated, considering the spatio-temporal context and technological characteristics. The comprehensive analysis of the Danish fleet over fifty years reveals long-term trends for several impact categories. Improvements in all categories follow similar trends as in climate change, which decreases from 40 to 13 g CO2-eq/kWh between 1980 and 2030. Improvements stem from combined economies of scale and higher load factors linked to increasingly large and powerful turbines. The interactive mapping tool LCA_WIND_DK may provide statistics to support renewable energy oriented policy scenarios and unique spatio-temporal environmental information to project developers. This novel approach designed for large territories, here applied to the Danish wind turbine fleet, is generic and can be applied to other renewable energy systems and/or to other territories

The Population Genomics of Pacific Herring in the Bering Sea using mtDNA

Research Poste

Ret Finger Protein: An E3 Ubiquitin Ligase Juxtaposed to the XY Body in Meiosis

During prophase I of male meiosis, the sex chromosomes form a compact structure called XY body that associates with the nuclear membrane of pachytene spermatocytes. Ret Finger Protein is a transcriptional repressor, able to interact with both nuclear matrix-associated proteins and double-stranded DNA. We report the precise and unique localization of Ret Finger Protein in pachytene spermatocytes, in which Ret Finger Protein takes place of lamin B1, between the XY body and the inner nuclear membrane. This localization of Ret Finger Protein does not seem to be associated with O-glycosylation or sumoylation. In addition, we demonstrate that Ret Finger Protein contains an E3 ubiquitin ligase activity. These observations lead to an attractive hypothesis in which Ret Finger Protein would be involved in the positioning and the attachment of XY body to the nuclear lamina of pachytene spermatocytes

Plasma natural 15N abundance may predict both feed conversion efficiency and residual feed intake in beef cattle across different dietary conditions

Cheap and rapid methods to predict between-animal variability of feed efficiency (FE) areneeded. We evaluated, by using a large dataset on beef cattle (n = 355) fed contrasting diets(grass vs corn based diets), the potential of plasma natural 15N abundance (δ15N) as abiomarker of between-animal variation in FE, measured either as feed conversion efficiency(FCE) or residual feed intake (RFI). Data were analyzed by mixed models, with diet and δ15Nas a fixed effect and experimental farm, batch and pen as random effects. A negative andsignificant correlation was found between FCE and δ15N within each contemporary group,with a lower response (slope) however in grass vs corn diets (δ15N × diet interaction; P =0.002). Likewise, we found a significant but positive relationship between δ15N and RFI, butwithout the influence of diet or any tested random effect. Our results indicate that δ15N is apromising biomarker of between-animal variation of feed efficiency (FCE and RFI) ingrowing beef cattle

Different Transport Mechanisms in Plant and Human AMT/Rh-type Ammonium Transporters

The conserved family of AMT/Rh proteins facilitates ammonium transport across animal, plant, and microbial membranes. A bacterial homologue, AmtB, forms a channel-like structure and appears to function as an NH3 gas channel. To evaluate the function of eukaryotic homologues, the human RhCG glycoprotein and the tomato plant ammonium transporter LeAMT1;2 were expressed and compared in Xenopus oocytes and yeast. RhCG mediated the electroneutral transport of methylammonium (MeA), which saturated with Km = 3.8 mM at pHo 7.5. Uptake was strongly favored by increasing the pHo and was inhibited by ammonium. Ammonium induced rapid cytosolic alkalinization in RhCG-expressing oocytes. Additionally, RhCG expression was associated with an alkali-cation conductance, which was not significantly permeable to NH4+ and was apparently uncoupled from the ammonium transport. In contrast, expression of the homologous LeAMT1;2 induced pHo-independent MeA+ uptake and specific NH4+ and MeA+ currents that were distinct from endogenous currents. The different mechanisms of transport, including the RhCG-associated alkali-cation conductance, were verified by heterologous expression in appropriate yeast strains. Thus, homologous AMT/Rh-type proteins function in a distinct manner; while LeAMT1;2 carries specifically NH4+, or cotransports NH3/H+, RhCG mediates electroneutral NH3 transport

Background

PROCEEDINGS A rich internet application for remote visualization and collaborative annotation of digital slides in histology and cytolog