541 research outputs found

    Select and Augment: Enhanced Dense Retrieval Knowledge Graph Augmentation

    Full text link
    Injecting textual information into knowledge graph (KG) entity representations has been a worthwhile expedition in terms of improving performance in KG oriented tasks within the NLP community. External knowledge often adopted to enhance KG embeddings ranges from semantically rich lexical dependency parsed features to a set of relevant key words to entire text descriptions supplied from an external corpus such as wikipedia and many more. Despite the gains this innovation (Text-enhanced KG embeddings) has made, the proposal in this work suggests that it can be improved even further. Instead of using a single text description (which would not sufficiently represent an entity because of the inherent lexical ambiguity of text), we propose a multi-task framework that jointly selects a set of text descriptions relevant to KG entities as well as align or augment KG embeddings with text descriptions. Different from prior work that plugs formal entity descriptions declared in knowledge bases, this framework leverages a retriever model to selectively identify richer or highly relevant text descriptions to use in augmenting entities. Furthermore, the framework treats the number of descriptions to use in augmentation process as a parameter, which allows the flexibility of enumerating across several numbers before identifying an appropriate number. Experiment results for Link Prediction demonstrate a 5.5% and 3.5% percentage increase in the Mean Reciprocal Rank (MRR) and Hits@10 scores respectively, in comparison to text-enhanced knowledge graph augmentation methods using traditional CNNs.Comment: Article has already been puclished to Journal of Artificial Intelligence Research (JAIR

    Age, growth rate, sexual dimorphism and fecundity of knobbed whelk Busycon carica (Gmelin, 1791) in a western mid-Atlantic lagoon system, Virginia

    Get PDF
    Growth, onset of sexual maturity, and sexual reversal in laboratory-reared Busycon carica have been examined. Animals first matured at 9 years of age. The first sign of maturity in all animals we reared was the presence of the penis. At 12.4 years of age, one of the animals laid an egg case that did not contain embryos. This animal, and all others, still retained a penis. At 13.5 years, three egg cases were laid and over half the animals had undergone sex reversal (loss of the penis). Field studies have shown that egg strings are laid in the fall on tidal and intertidal flats and over winter to hatch in the spring. Organisms that require a relatively long time to mature, that lay few eggs per spawning season, and that are vulnerable for a long time are difficult to manage for a sustained yield fishery

    Plant pathogens as biological agents for the control of weeds

    Get PDF
    Weed control is by far the most pervasive and costly need in agriculture, both in underdevel­ oped as well as in technologically advanced production systems. In 1994, losses due to weeds in U.S. agriculture—including herbi­ cide costs and yield losses—amounted to over $ 15 billion, and about 96% of the more than 21 million acres of row crops grown in Iowa received at least one chemical herbicide appli­ cation. Pesticide use statistics reveal that more herbicides are used than any other class of pesticide. Despite the extensive use of herbi­ cides, certain weed species continue to cause problems in agriculture, and current control strategies for some of these are inadequate. Among these weeds are johnsongrass (Sor­ ghum halapense), the morning glorys (Ipomoea spp.), nutsedges (Cyperus esculentus), shattercane (Sorghum bicolor), and velvetleaf (Abutillon theophrasti)

    Team-Based Learning in Engineering Classrooms: Feedback Form and Content Adds Value to the Learning Experience

    Get PDF
    An instructional strategy called Team-Based Learning (TBL) has been implemented by the authors in courses that emphasize fundamental engineering concepts that are core to the discipline. TBL is an alternative to conventional classroom lecture instruction. In a TBL course, students are placed on permanent learning teams and the teams work together, during class time, to apply course concepts and solve discipline-relevant problems called application exercises. The goal of introducing TBL in these engineering courses is to enhance the quality of student learning by incentivizing student engagement with course content and fostering team skills. This is achieved by using application exercises that require student teams to apply critical thinking and decision making abilities. Students on high performing teams routinely report that their team’s success on application exercises is directly attributable to the thorough preparation by individual student team members outside of class, and that the TBL course structure helped them develop and enhance their ability to learn challenging concepts on their own. An important component of TBL course structure is the inclusion of frequent, timely, and varied types of instructional feedback to students. This paper will introduce a taxonomy for instructional feedback and place the feedback mechanisms that are inherent in the TBL course structure within this context. The form and content of instructional feedback used in TBL engineering courses will be examined. This discussion will include suggestions for achieving a balance between the dimensions of feedback to facilitate the professional development of engineering students

    Host-Switching Does not Circumvent the Ni-based Defence of the Ni hyperaccumulator \u3ci\u3eStreptanthus polygaloides\u3c/i\u3e (Brassicaceae)

    Get PDF
    Elevated tissue concentrations of metals have been shown to defend metal-hyperaccumulating plants against both herbivores and pathogens. Tolerance of metal-based defences presents a challenge to herbivores, because heavy metals cannot be degraded or metabolized. One strategy that herbivores can employ to counter high-metal defences is dietary dilution, or host switching. Highly mobile herbivores are most likely to use this strategy, but less mobile lepidopteran larvae can also Improve their performance on toxic hosts if early instar development occurs on more favourable hosts. We examined the effects of host switching on growth and survival of a generalist folivore. Specifically, we tested the hypothesis that early larval development on non-toxic hosts could improve larval performance of the beet armyworm, Spodoptera exigua, an high-Ni Streptanthus polygaloides, a Ni hyperaccumulator. Initial larval performance (weight gain) was lowest for insects switched to high-N! hosts. Decreased initial larval performance was also noted for insects switched from lettuce to low-Ni S. polygaloides, but these larvae recovered quickly. Original host identity (lettuce or low-Ni S. polygaloides) did not affect subsequent larval performance. By day 8 of the feeding trials, all larvae switched to high-Ni hosts had died. We conclude that polyphagous Spodoptera larvae are unable to counter NI-based defences via host switching

    Relationships between HI Gas Mass, Stellar Mass and Star Formation Rate of HICAT+WISE (HI-WISE) Galaxies

    Get PDF
    We have measured the relationships between HI mass, stellar mass and star formation rate using the HI Parkes All Sky-Survey Catalogue (HICAT) and the Wide-field Infrared Survey Explorer (WISE). Of the 3,513 HICAT sources, we find 3.4 micron counterparts for 2,896 sources (80%) and provide new WISE matched aperture photometry for these galaxies. For our principal sample of spiral galaxies with W1 ≤\le 10 mag and z ≤\le 0.01, we identify HI detections for 93% of the sample. We measure lower HI-stellar mass relationships that HI selected samples that do not include spiral galaxies with little HI gas. Our observations of the spiral sample show that HI mass increases with stellar mass with a power-law index 0.35; however, this value is dependent on T-type, which affects both the median and the dispersion of HI mass. We also observe an upper limit on the HI gas fraction, which is consistent with a halo spin parameter model. We measure the star formation efficiency of spiral galaxies to be constant 10−9.57^{-9.57} yr−1^{-1} ±\pm 0.4 dex for 2.5 orders of magnitude in stellar mass, despite the higher stellar mass spiral showing evidence of quenched star formation.Comment: 20 pages, 13 figures; accepted for publication by Ap

    Cortical Activity Measured with Low-Intensity Fatiguing Contractions of the Quadriceps Muscle Group

    Get PDF
    Modulation of force production required during exercise is regulated from various mechanisms in the central and peripheral nervous system. Fatigue is influenced by various mechanics that may hinder the ability to continuously sustain force production. The neural activation patterns of these systems can be recorded as electrical impulses using several non-invasive techniques. The ability to examine these during fatiguing exercise has provided further insight into activation patterns in the central nervous system (i.e., motor and pre-motor cortex) during sustained muscle contractions. Electroencephalography (EEG) has been recently utilized to examine changes associated with central fatigue, but limited advancements in technology for neuromuscular fatigue has inhibited progression in this area of research. PURPOSE:The purpose of this study is to discover the effects of low-intensity muscular fatigue on central mechanisms. METHODS:Following 3 Maximal Voluntary Contractions (MVCs), four lower-body resistance trained males (23yrs.±2, ht.176cm ±6., wt. 89kg ±16.) performed 60 second submaximal (30% MVC) isometric ramp contraction of the knee extension exercise. Knee extensions were performed on a custom-built seat using an S-beam load-cell to measure isometric force production of the quadriceps muscle group. During the fatiguing contractions, participants were encouraged to perform as many trapezoidal ramp contractions (i.e., 30%) as possible, until they could no longer sustain the required force production. Fatigue was established when the participant could no longer maintain the contraction force within 10% for no less than 3 seconds during the isometric hold.Cortical activity was recorded with a 24-electrode electroencephalogram (EEG) soft cap. Once EEG signals were referenced, bandpass filtered, and cleaned, gamma and beta frequency band data and topographic maps were computed for electrodes over the cerebral cortex (C3, Cz, and C4). Two separate repeated measures ANOVAs were used to compare the band’s during the first 3 seconds of the force plateau of the pre and post contractions.RESULTS:There were no significant differences over time in any of the electrodes/bands (p\u3e .05). DISCUSSION:These data indicate that low-intensity muscular fatigue is not mediated by central mechanisms in the C3, C4, Cz electrode spaces in the higher frequency bands (beta and gamma). Future research will examine other central mechanisms that underlie the neural circuit involved in muscular fatigue

    Dystrophin glycoprotein complex dysfunction:a regulatory link between muscular dystrophy and cancer cachexia

    Get PDF
    SummaryCachexia contributes to nearly a third of all cancer deaths, yet the mechanisms underlying skeletal muscle wasting in this syndrome remain poorly defined. We report that tumor-induced alterations in the muscular dystrophy-associated dystrophin glycoprotein complex (DGC) represent a key early event in cachexia. Muscles from tumor-bearing mice exhibited membrane abnormalities accompanied by reduced levels of dystrophin and increased glycosylation on DGC proteins. Wasting was accentuated in tumor mdx mice lacking a DGC but spared in dystrophin transgenic mice that blocked induction of muscle E3 ubiquitin ligases. Furthermore, DGC deregulation correlated positively with cachexia in patients with gastrointestinal cancers. Based on these results, we propose that, similar to muscular dystrophy, DGC dysfunction plays a critical role in cancer-induced wasting
    • …
    corecore