Kahler submanifolds and the Umehara algebra

We show that an indefinite Euclidean complex space is not a relative of an indefinite non-flat complex space form. We further study whether two compact Fubini-Study spaces are relatives or not

Receiver Operating Characteristic (ROC) Area Under the Curve (AUC): A Diagnostic Measure for Evaluating the Accuracy of Predictors of Education Outcomes

Early Warning Systems (EWS) and Early Warning Indictors (EWI) have recently emerged as an attractive domain for states and school districts interested in predicting student outcomes using data that schools already collect with the intention to better time and tailor interventions. However, current diagnostic measures used across the domain do not consider the dual issues of sensitivity and specificity of predictors, key components for considering accuracy. We apply signal detection theory using Receiver Operating Characteristic (ROC) Area Under the Curve (AUC) analysis adapted from the engineering and medical domains, and using the pROC package in R. Using nationally generalizable data from the Education Longitudinal Study of 2002 (ELS:2002) we provide examples of applying ROC accuracy analysis to a variety of predictors of student outcomes, such as dropping out of high school, college enrollment, and postsecondary STEM degrees and careers. Keywords: ROC, AUC, Early Warning System, Early Warning Indicator, signal detection theory, dropout, college enrollment, Postsecondary STEM Degree, hard STEM career, soft STEM caree

Targeted expression of truncated glued disrupts giant fiber synapse formation in Drosophila

Glued1 (Gl1) mutants produce a truncated protein that acts as a poison subunit and disables the cytoplasmic retrograde motor dynein. Heterozygous mutants have axonal defects in the adult eye and the nervous system. Here we show that selective expression of the poison subunit in neurons of the giant fiber (GF) system disrupts synaptogenesis between the GF and one of its targets, the tergotrochanteral motorneuron (TTMn). Growth and pathfinding by the GF axon and the TTMn dendrite are normal, but the terminal of the GF axon fails to develop normally and becomes swollen with large vesicles. This is a presynaptic defect because expression of truncated Glued restricted to the GF results in the same defect. When tested electrophysiologically, the flies with abnormal axons show a weakened or absent GF-TTMn connection. In Glued1 heterozygotes, GF-TTMn synapse formation appears morphologically normal, but adult flies show abnormal responses to repetitive stimuli. This physiological effect is also observed when tetanus toxin is expressed in the GFs. Because the GF-TTMn is thought to be a mixed electrochemical synapse, the results show that Glued has a role in assembling both the chemical and electrical components. We speculate that disrupting transport of a retrograde signal disrupts synapse formation and maturation

Kahler submanifolds and the Umehara algebra

We show that indefinite Euclidean spaces and indefinite non-flat complex space forms are relatives. We also study when two Fubini-Study spaces are relatives

Activity Assay of Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Triple-Negative Breast Cancer Cells Using Peptide-Conjugated Magnetic Beads

Triple-negative breast cancer (TNBC) is a highly aggressive subtype of breast cancer with limited treatment options. Epidermal growth factor receptor I (EGFR) has emerged as a promising target in TNBC. Limited success of the EGFR kinase inhibiting small molecules in clinical trials may be attributed in part to inaccuracy in identifying EGFR signatures in patient tumors. In light of the absence of a simple correlation between EGFR expression and its degree of activation, a simple and reliable tool that can quantify EGFR kinase activity in tumor samples may be of therapeutic value in predicting patient-specific EGFR targeted therapies. This study reports the development of an assay that can quantitatively profile EGFR kinase activities and inhibitor sensitivities in TNBC cell lysates by using peptide reporters covalently tethered to magnetic beads in a controlled orientation. The use of magnetic beads provides rapid sample handling and easy product isolation. The potential of this approach was demonstrated by screening a set of five clinically relevant EGFR tyrosine kinase inhibitors. Formatted for microwell plates, this magnetic bead-based kinase assay may be used as a complementary approach for direct high-throughput screening of small molecule inhibitors.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140099/1/adt.2012.454.pd

Zirconia-Based Electrolyte Stability in Direct-Carbon Fuel Cells with Molten Sb Anodes

Direct carbon fuel cells (DCFC) that use zirconia-based electrolytes and molten Sb anodes have much promise for the efficient conversion of carbonaceous solid fuels into electricity. However, etching of the electrolyte, and ultimately cell failure, has been observed during operation. In this study, we have investigated this etching phenomenon as a function of the electrolyte composition and cell operating conditions and demonstrated that it is not electrochemical in nature, but rather results from reaction between the electrolyte and Sb2O3

A Typology of Parental Involvement in Student Experience: A Latent Class Analysis

We examine the extent to which there are significantly different types of Parental Involvement in student’s high school experience, and what the relationship of these different types may be to long-term student outcomes, such as high school graduation, college going, and specifically for this study, STEM career outcomes. With the dataset the Education Longitudinal Study of 2002 (ELS:2002) which includes 11,727 parents of high school students in the United States, we examine how parents interact with students and schools using Latent Class Analysis (LCA). We identify three significantly different subgroups of parent involvement: Guiding (44.2%), Lenient (22.3%), and Advocate (33.5%). Parental context and demographic factors, such as gender and ethnicity, and school variables, such as private status and school size, are significantly associated with membership across subgroups, which in turn are related to students’ education outcomes, such as college enrollment and selection of a STEM career versus other career outcomes

A Data-Driven Analysis of a Tactical Surface Scheduler

NASA's Airspace Technology Demonstration-2 (ATD-2) integrates arrival, departure, and surface operations to extend integrated traffic sequencing all the way from the gate to the overhead stream and back again for multi-airport, metroplex environments. A key concept of ATD-2 centers on surface scheduling that allows aircraft to taxi, climb, and insert within the overhead stream with minimal interruptions. A core principle is to allow aircraft to absorb delay at the gate prior to engine start in order to reduce overall fuel burn and emissions. To achieve these goals, it is necessary for the scheduler to properly balance the demand at the runway with the available capacity while also predicting accurate takeoff times. This paper provides a data-driven analysis of the runway demand capacity balancing and measures the accuracy of schedules that are generated while running in a live operational environment at the Charlotte Douglas International Airport. We found that using minimum-time wake vortex separation constraints to define runway capacity resulted in scheduling departure operations at a slightly higher rate than the runway was operating and we discovered a surprising relationship between the runway rate and the accuracy of the schedules

Gallium/aluminum interdiffusion between n-GaN and sapphire

The distribution profiles of Ga and Al near the interface of the n-GaN/sapphire system were measured by x-ray energy dispersive spectroscopy (XEDS). The results are obtained by the corrected XED spectra. First, the gallium diffusing into the sapphire substrate obeys the law of remainder probability function. The gallium diffusion coefficient DGa=2.30×10-13 cm2s-1 was calculated by theoretical fitting. Second, the diffusion is associated with the GaN growth process at high temperature. Compared to the diffusion of Ga into the sapphire substrate, much less Al antidiffusion from the substrate to the GaN film, with diffusion coefficient DA1 approximately equal to 4.8×10-15 cm2s-1, was observed in the film. © 1998 American Institute of Physics.published_or_final_versio

Chlorophyll fluorescence tracks seasonal variations of photosynthesis from leaf to canopy in a temperate forest

Author Posting. © The Author(s), 2016. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Global Change Biology 23 (2017): 2874-2886, doi: 10.1111/gcb.13590.Accurate estimation of terrestrial gross primary productivity (GPP) remains a challenge despite its importance in the global carbon cycle. Chlorophyll fluorescence (ChlF) has been recently adopted to understand photosynthesis and its response to the environment, particularly with remote sensing data. However, it remains unclear how ChlF and photosynthesis are linked at different spatial scales across the growing season. We examined seasonal relationships between ChlF and photosynthesis at the leaf, canopy, and ecosystem scales, and explored how leaf-level ChlF was linked with canopy-scale solar induced chlorophyll fluorescence (SIF) in a temperate deciduous forest at Harvard Forest, Massachusetts, USA. Our results show that ChlF captured the seasonal variations of photosynthesis with significant linear relationships between ChlF and photosynthesis across the growing season over different spatial scales (R2=0.73, 0.77 and 0.86 at leaf, canopy and satellite scales, respectively; p<0.0001). We developed a model to estimate GPP from the tower-based measurement of SIF and leaf-level ChlF parameters. The estimation of GPP from this model agreed well with flux tower observations of GPP (R2=0.68; p<0.0001), demonstrating the potential of SIF for modeling GPP. At the leaf scale, we found that leaf Fq’/Fm’, the fraction of absorbed photons that are used for photochemistry for a light adapted measurement from a pulse amplitude modulation fluorometer, was the best leaf fluorescence parameter to correlate with canopy-SIF yield (SIF/APAR, R2=0.79; p<0.0001). We also found that canopy-SIF and SIF-derived GPP (GPPSIF) were strongly correlated to leaf-level biochemistry and canopy structure, including chlorophyll content (R2=0.65 for canopy-GPPSIF and chlorophyll content; p<0.0001), leaf area index (LAI) (R2=0.35 for canopy-GPPSIF and LAI; p<0.0001), and normalized difference vegetation index (NDVI) (R2=0.36 for canopy-GPPSIF and NDVI; p<0.0001). Our results suggest that ChlF can be a powerful tool to track photosynthetic rates at leaf, canopy, and ecosystem scales.This research was supported by U.S. Department of Energy Office of Biological and Environmental Research Grant DE-SC0006951, National Science Foundation Grants DBI-959333 and AGS-1005663, and the University of Chicago and the MBL Lillie Research Innovation Award to J. Tang, National Science Foundation of China Grants (41671421) to Y. Zhang, and China Scholarship Council (CSC) to H. Yang.2017-12-1