First Principle Quantum Description of the Energetics Associated with LaBr3, LaC13, and Ce Doped Scintillators

Considerable interest is given to the excellent scintillation properties of cerium doped lanthanum chloride (LaCl3) and lanthanum bromide (LaBr3). The scintillation efficiencies are much greater than other materials, even those containing cerium. This high efficiency is attributed to the high mobility of electrons and holes, unique placement of the cerium 5d states within the band gap, and energy of the band gap. To better understand the scintillation process and better define the nature of the Self Trapped Exciton (STE) within these unique scintillation materials, density functional theory (DFT), and Ab-inito (HF-MP2) calculations are reported. DFT calculations have yielded a qualitative description of the orbital composition and energy distribution of the band structure in the crystalline material. MP2 and single configuration interaction calculations have provided quantitative values for the band gap and provided energies for the possible range of excited states created following hole and electron creation. Based on this theoretical treatment, one possible description of the STE is the combination of Vk center (Br2-1) and LaBr+1 species that recombine to form a distorted geometry LaBr3* (triplet state). Depending on the distance between the LaBr and Br2, the STE emission band can be reproduced

First Principle Quantum Description of the Energetics Associated with LaBr3, LaCl3, and Ce Doped Scintillators

Considerable interest is given to the excellent scintillation properties of cerium doped lanthanum chloride (LaCl3) and lanthanum bromide (LaBr3). The scintillation efficiencies are much greater than other materials, even those containing cerium. This high efficiency is attributed to the high mobility of electrons and holes, unique placement of the cerium 5d states within the band gap, and energy of the band gap. To better understand the scintillation process and better define the nature of the Self Trapped Exciton (STE) within these unique scintillation materials, density functional theory (DFT), and Ab-inito (HF-MP2) calculations are reported. DFT calculations have yielded a qualitative description of the orbital composition and energy distribution of the band structure in the crystalline material. MP2 and single configuration interaction calculations have provided quantitative values for the band gap and provided energies for the possible range of excited states created following hole and electron creation. Based on this theoretical treatment, one possible description of the STE is the combination of Vk center (Br2-1) and LaBr+1 species that recombine to form a distorted geometry LaBr3* (triplet state). Depending on the distance between the LaBr and Br2, the STE emission band can be reproduced

Global energy transfer during a magnetospheric field line resonance

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95367/1/grl28194.pd

Multiomics modeling of the immunome, transcriptome, microbiome, proteome and metabolome adaptations during human pregnancy.

MotivationMultiple biological clocks govern a healthy pregnancy. These biological mechanisms produce immunologic, metabolomic, proteomic, genomic and microbiomic adaptations during the course of pregnancy. Modeling the chronology of these adaptations during full-term pregnancy provides the frameworks for future studies examining deviations implicated in pregnancy-related pathologies including preterm birth and preeclampsia.ResultsWe performed a multiomics analysis of 51 samples from 17 pregnant women, delivering at term. The datasets included measurements from the immunome, transcriptome, microbiome, proteome and metabolome of samples obtained simultaneously from the same patients. Multivariate predictive modeling using the Elastic Net (EN) algorithm was used to measure the ability of each dataset to predict gestational age. Using stacked generalization, these datasets were combined into a single model. This model not only significantly increased predictive power by combining all datasets, but also revealed novel interactions between different biological modalities. Future work includes expansion of the cohort to preterm-enriched populations and in vivo analysis of immune-modulating interventions based on the mechanisms identified.Availability and implementationDatasets and scripts for reproduction of results are available through: https://nalab.stanford.edu/multiomics-pregnancy/.Supplementary informationSupplementary data are available at Bioinformatics online

Kinetic model of the inner magnetosphere with arbitrary magnetic field

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95311/1/jgra21699.pd

Is Mislocalization during saccades related to the position of the saccade target within the image or to the gaze position at the end of the saccade?

A stimulus that is flashed around the time of a saccade tends to be mislocalized in the direction of the saccade target. Our question is whether the mislocalization is related to the position of the saccade target within the image or to the gaze position at the end of the saccade. We separated the two with a visual illusion that influences the perceived distance to the target of the saccade and thus saccade endpoint without affecting the perceived position of the saccade target within the image. We asked participants to make horizontal saccades from the left to the right end of the shaft of a Müller-Lyer figure. Around the time of the saccade, we flashed a bar at one of five possible positions and asked participants to indicate its location by touching the screen. As expected, participants made shorter saccades along the fins-in (<->) configuration than along the fins-out (>-<) configuration of the figure. The illusion also influenced the mislocalization pattern during saccades, with flashes presented with the fins-out configuration being perceived beyond flashes presented with the fins-in configuration. The difference between the patterns of mislocalization for bars flashed during the saccade for the two configurations corresponded quantitatively with a prediction based on compression towards the saccade endpoint considering the magnitude of the effect of the illusion on saccade amplitude. We conclude that mislocalization is related to the eye position at the end of the saccade, rather than to the position of the saccade target within the image

Scientific Opportunities to Reduce Risk in Nuclear Process Science

Cleaning up the nation’s nuclear weapons complex remains as one of the most technologically challenging and financially costly problems facing the U.S. Department of Energy (DOE). Safety, cost, and technological challenges have often delayed progress in retrieval, processing, and final disposition of high-level waste, spent nuclear fuel, and challenging materials. Some of the issues result from the difficulty and complexity of the technological issues; others have programmatic bases, such as contracting strategies that may provide undue focus on near-term, specific clean-up goals or difficulty in developing and maintaining stakeholder confidence in the proposed solutions. We propose that independent basic fundamental science research focused on the full cleanup life-cycle offers an opportunity to help address these challenges by providing 1) scientific insight into the fundamental mechanisms involved in currently selected processing and disposal options, 2) a rational path to the development of alternative technologies should the primary options fail, 3) confidence that models that predict long-term performance of different disposal options are based upon the best available science, 4) fundamental science discovery that enables transformational solutions to revolutionize the current baseline processes

Comparative phylogeography of reef fishes from the Gulf of Aden to the Arabian Sea reveals two cryptic lineages

Arabian Sea is a heterogeneous region with high coral cover and warm stable conditions at the western end (Djibouti), in contrast to sparse coral cover, cooler temperatures, and upwelling at the eastern end (southern Oman). We tested for barriers to dispersal across this region (including the Gulf of Aden and Gulf of Oman), using mitochondrial DNA surveys of 11 reef fishes. Study species included seven taxa from six families with broad distributions across the Indo-Pacific and four species restricted to the Arabian Sea (and adjacent areas). Nine species showed no significant genetic partitions, indicating connectivity among contrasting environments spread across 2000 km. One butterflyfish (Chaetodon melannotus) and a snapper (Lutjanus kasmira) showed phylogenetic divergences of d = 0.008 and 0.048, respectively, possibly indicating cryptic species within these broadly distributed taxa. These genetic partitions at the western periphery of the Indo-Pacific reflect similar partitions recently discovered at the eastern periphery of the Indo-Pacific (the Hawaiian and the Marquesan Archipelagos), indicating that these disjunctive habitats at the ends of the range may serve as evolutionary incubators for coral reef organisms. © 2017 Springer-Verlag Berlin HeidelbergTh

The Earth: Plasma Sources, Losses, and Transport Processes

This paper reviews the state of knowledge concerning the source of magnetospheric plasma at Earth. Source of plasma, its acceleration and transport throughout the system, its consequences on system dynamics, and its loss are all discussed. Both observational and modeling advances since the last time this subject was covered in detail (Hultqvist et al., Magnetospheric Plasma Sources and Losses, 1999) are addressed