124 research outputs found

    Eclipsing binary and white dwarf features associated with K2 target EPIC251248385

    Full text link
    White dwarfs, remnants of Sun-like stars which have completed their evolution, are one of the most common types of stars in space. Despite this, very few white dwarfs have been observed in transiting or eclipsing systems, and only two planetary systems around white dwarfs are currently known, thus motivating a search for white dwarfs with transits or eclipses as seen by the Kepler telescope. A systematic search of K2 white dwarf targets revealed one candidate with regular eclipses, but additional research was necessary to confirm the transits and white dwarf signal were coming from the same astrophysical source. The software package PyKe was utilized to adjust the light curve aperture, and perform principal component analysis which revealed that the transits were originating from a single pixel. Generating a new lightcurve from this pixel revealed the absolute transit depth, which was unconstrained previously. Ten additional images taken with the 2m LCOGT telescope revealed that a potential target star in the single Kepler pixel was actually a cluster of three stars, but no clear transits were seen from any of the potential target stars in the followup images. Additionally, analysis of transit depths in the single pixel light curve and additional investigation of nearby bright sources supported the hypothesis that the transits were more likely to be coming from the white dwarf rather than the two other sources. However, the transit duration and shape appear atypical for white dwarf systems. Thus, despite determining the potential sources and relative sizes for the potential eclipsing white dwarf candidate, or whether the eclipses come from the white dwarf target cannot be confirmed without additional data.https://iopscience.iop.org/article/10.3847/2515-5172/ab5861Published versio

    Optimization of the carrier concentration in phase-separated half-Heusler compounds

    Get PDF
    Inspired by the promising thermoelectric properties of phase-separated half-Heusler materials, we investigated the influence of electron doping in the n-type Ti_(0.3−x)Zr_(0.35)Hf_(0.35)NiSn compound. The addition of Nb to this compound led to a significant increase in its electrical conductivity, and shifted the maximum Seebeck coefficient to higher temperatures owing to the suppression of intrinsic carriers. This resulted in an enhancement of both the power factor α^2σ and figure of merit, zT. The applicability of an average effective mass model revealed the optimized electron properties for samples containing Nb. There is evidence in the literature that the average effective mass model is suitable for estimating the optimized carrier concentration of thermoelectric n-type half-Heusler compounds

    Leveling the Legal Malpractice Playing Field: Reverse Bifurcation of Trials The Fourth Annual Symposium on Legal Malpractice and Professional Responsibility.

    Get PDF
    The growing public demand for perfect results is shifting the time-tested obligation of lawyers to meet the standard of care. The general public no longer deems the advice and performance of professionals as beyond reproach. While this is probably a positive development, it appears that a number of clients (and patients) are raising the bar too high by expecting and demanding a perfect result. The legal malpractice suit is in vogue, and juries are increasingly holding attorneys to be guarantors of a favorable outcome for their clients. A significant portion of legal malpractice suits are merely thinly veiled claims for an assumed “Breach of Implied Warranty of Perfect Result.” These claims represent a shift in expectations which threatens to upset the balance between negligence and strict liability established and proven by decades of experience and tradition. In the face of shifting public expectations, routine procedures fail to bring the distinction between duty and results into focus, often holding the attorney to a higher standard of conduct than the law requires. The very nature of a legal malpractice trial is sufficiently unique to warrant special procedural attention. Innovative procedures are necessary to level the legal malpractice playing field and shield attorneys from liability for “Breach of the Implied Warranty of Perfect Result.” A reverse bifurcation method in which a plaintiff-client must first prove the validity of his claim or defense in the underlying case honors the principle that an attorney is not a guarantor of results and is presumed to have competently represented his or her client

    Leveling the Legal Malpractice Playing Field: Reverse Bifurcation of Trials The Fourth Annual Symposium on Legal Malpractice and Professional Responsibility.

    Get PDF
    The growing public demand for perfect results is shifting the time-tested obligation of lawyers to meet the standard of care. The general public no longer deems the advice and performance of professionals as beyond reproach. While this is probably a positive development, it appears that a number of clients (and patients) are raising the bar too high by expecting and demanding a perfect result. The legal malpractice suit is in vogue, and juries are increasingly holding attorneys to be guarantors of a favorable outcome for their clients. A significant portion of legal malpractice suits are merely thinly veiled claims for an assumed “Breach of Implied Warranty of Perfect Result.” These claims represent a shift in expectations which threatens to upset the balance between negligence and strict liability established and proven by decades of experience and tradition. In the face of shifting public expectations, routine procedures fail to bring the distinction between duty and results into focus, often holding the attorney to a higher standard of conduct than the law requires. The very nature of a legal malpractice trial is sufficiently unique to warrant special procedural attention. Innovative procedures are necessary to level the legal malpractice playing field and shield attorneys from liability for “Breach of the Implied Warranty of Perfect Result.” A reverse bifurcation method in which a plaintiff-client must first prove the validity of his claim or defense in the underlying case honors the principle that an attorney is not a guarantor of results and is presumed to have competently represented his or her client

    Iterative focused screening with biological fingerprints identifies selective Asc-1 inhibitors distinct from traditional high throughput screening

    Get PDF
    N-methyl-d-aspartate receptors (NMDARs) mediate glutamatergic signaling that is critical to cognitive processes in the central nervous system, and NMDAR hypofunction is thought to contribute to cognitive impairment observed in both schizophrenia and Alzheimer’s disease. One approach to enhance the function of NMDAR is to increase the concentration of an NMDAR coagonist, such as glycine or d-serine, in the synaptic cleft. Inhibition of alanine–serine–cysteine transporter-1 (Asc-1), the primary transporter of d-serine, is attractive because the transporter is localized to neurons in brain regions critical to cognitive function, including the hippocampus and cortical layers III and IV, and is colocalized with d-serine and NMDARs. To identify novel Asc-1 inhibitors, two different screening approaches were performed with whole-cell amino acid uptake in heterologous cells stably expressing human Asc-1: (1) a high-throughput screen (HTS) of 3 M compounds measuring 35S l-cysteine uptake into cells attached to scintillation proximity assay beads in a 1536 well format and (2) an iterative focused screen (IFS) of a 45 000 compound diversity set using a 3H d-serine uptake assay with a liquid scintillation plate reader in a 384 well format. Critically important for both screening approaches was the implementation of counter screens to remove nonspecific inhibitors of radioactive amino acid uptake. Furthermore, a 15 000 compound expansion step incorporating both on- and off-target data into chemical and biological fingerprint-based models for selection of additional hits enabled the identification of novel Asc-1-selective chemical matter from the IFS that was not identified in the full-collection HTS

    Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context

    Get PDF
    Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts

    Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas

    Get PDF
    Although theMYConcogene has been implicated incancer, a systematic assessment of alterations ofMYC, related transcription factors, and co-regulatoryproteins, forming the proximal MYC network (PMN),across human cancers is lacking. Using computa-tional approaches, we define genomic and proteo-mic features associated with MYC and the PMNacross the 33 cancers of The Cancer Genome Atlas.Pan-cancer, 28% of all samples had at least one ofthe MYC paralogs amplified. In contrast, the MYCantagonists MGA and MNT were the most frequentlymutated or deleted members, proposing a roleas tumor suppressors.MYCalterations were mutu-ally exclusive withPIK3CA,PTEN,APC,orBRAFalterations, suggesting that MYC is a distinct onco-genic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such asimmune response and growth factor signaling; chro-matin, translation, and DNA replication/repair wereconserved pan-cancer. This analysis reveals insightsinto MYC biology and is a reference for biomarkersand therapeutics for cancers with alterations ofMYC or the PMN
    corecore