2,352 research outputs found

    Timescale Dependence in River Channel Migration Measurements

    Get PDF
    Accurately measuring river meander migration over time is critical for sediment budgets and understanding how rivers respond to changes in hydrology or sediment supply. However, estimates of meander migration rates or streambank contributions to sediment budgets using repeat aerial imagery, maps, or topographic data will be underestimated without proper accounting for channel reversal. Furthermore, comparing channel planform adjustment measured over dissimilar timescales are biased because short‐ and long‐term measurements are disproportionately affected by temporary rate variability, long‐term hiatuses, and channel reversals. We evaluate the role of timescale dependence for the Root River, a single threaded meandering sand‐ and gravel‐bedded river in southeastern Minnesota, USA, with 76 years of aerial photographs spanning an era of landscape changes that have drastically altered flows. Empirical data and results from a statistical river migration model both confirm a temporal measurement‐scale dependence, illustrated by systematic underestimations (2–15% at 50 years) and convergence of migration rates measured over sufficiently long timescales (\u3e 40 years). Frequency of channel reversals exerts primary control on measurement bias for longer time intervals by erasing the record of observable migration. We conclude that using long‐term measurements of channel migration for sediment remobilization projections, streambank contributions to sediment budgets, sediment flux estimates, and perceptions of fluvial change will necessarily underestimate such calculations. © 2019 John Wiley & Sons, Ltd

    Neural Responses to Novel and Existing Words in Children with Autism Spectrum and Developmental Language Disorder

    Get PDF
    \ua9 2021, the Authors.The formation of new phonological representations is key in establishing items in the mental lexicon. Phonological forms become stable with repetition, time and sleep. Atypicality in the establishment of new word forms is characteristic of children with developmental language disorder (DLD) and autism spectrum disorder (ASD), yet neural changes in response to novel word forms over time have not yet been directly compared in these groups. This study measured habituation of event-related-potentials (ERPs) to novel and known words within and between two sessions spaced 24 hours apart in typically developing (TD) children, and their peers with DLD or ASD. We hypothesised that modulation of the auditory N400 amplitude would mark real-time changes in lexical processing with habituation evident within and across sessions in the TD group, while the DLD group would show attenuated habituation within sessions, and the ASD group attenuated habituation between sessions. Twenty-one typically developing children, 19 children with ASD, and 16 children with DLD listened passively to known and novel words on two consecutive days, while ERPs were recorded using dry electrodes. Counter to our hypotheses, no habituation effect emerged within sessions. However, responses did habituate between sessions, with this effect being reduced in the DLD group, indicating less pre-activation of lexical representations in response to words encountered the previous day. No differences in change over time were observed between the TD and ASD groups. These data are in keeping with theories stressing the importance of sleep-related consolidation in word learning

    On the evaluation and improvement of arabic wordnet coverage and usability

    Full text link
    The final publication is available at Springer via http://dx.doi.org/10.1007/s10579-013-9237-0[EN] Built on the basis of the methods developed for Princeton WordNet and EuroWordNet, Arabic WordNet (AWN) has been an interesting project which combines WordNet structure compliance with Arabic particularities. In this paper, some AWN shortcomings related to coverage and usability are addressed. The use of AWN in question/answering (Q/A) helped us to deeply evaluate the resource from an experience-based perspective. Accordingly, an enrichment of AWN was built by semi-automatically extending its content. Indeed, existing approaches and/or resources developed for other languages were adapted and used for AWN. The experiments conducted in Arabic Q/A have shown an improvement of both AWN coverage as well as usability. Concerning coverage, a great amount of named entities extracted from YAGO were connected with corresponding AWN synsets. Also, a significant number of new verbs and nouns (including Broken Plural forms) were added. In terms of usability, thanks to the use of AWN, the performance for the AWN-based Q/A application registered an overall improvement with respect to the following three measures: accuracy (+9.27 % improvement), mean reciprocal rank (+3.6 improvement) and number of answered questions (+12.79 % improvement).The work presented in Sect. 2.2 was done in the framework of the bilateral Spain-Morocco AECID-PCI C/026728/09 research project. The research of the two first authors is done in the framework of the PROGRAMME D'URGENCE project (grant no. 03/2010). The research of the third author is done in the framework of WIQEI IRSES project (grant no. 269180) within the FP 7 Marie Curie People, DIANA-APPLICATIONS-Finding Hidden Knowledge in Texts: Applications (TIN2012-38603-C02-01) research project and VLC/CAMPUS Microcluster on Multimodal Interaction in Intelligent Systems. We would like to thank Manuel Montes-y-Gomez (INAOE-Puebla, Mexico) and Sandra Garcia-Blasco (Bitsnbrain, Spain) for their feedback on the work presented in Sect. 2.4. We would like finally to thank Violetta Cavalli-Sforza (Al Akhawayn University in Ifrane, Morocco) for having reviewed the linguistic level of the entire document.Abouenour, L.; Bouzoubaa, K.; Rosso, P. (2013). On the evaluation and improvement of arabic wordnet coverage and usability. Language Resources and Evaluation. 47(3):891-917. https://doi.org/10.1007/s10579-013-9237-0S891917473AbbĂšs, R., Dichy, J., & Hassoun, M. (2004). The architecture of a standard Arabic lexical database: Some figures, ratios and categories from the DIINAR.1 source program. In Workshop on computational approaches to Arabic script-based languages, Coling 2004. Geneva, Switzerland.Abouenour, L., Bouzoubaa, K., & Rosso, P. (2009a). Structure-based evaluation of an Arabic semantic query expansion using the JIRS passage retrieval system. In Proceedings of the workshop on computational approaches to Semitic languages, E-ACL-2009, Athens, Greece, March.Abouenour, L., Bouzoubaa, K., & Rosso, P. (2009b). Three-level approach for passage retrieval in Arabic question/answering systems. In Proceedings of the 3rd international conference on Arabic language processing CITALA’09, Rabat, Morocco, May, 2009.Abouenour, L., Bouzoubaa, K., & Rosso, P. (2010a). An evaluated semantic query expansion and structure-based approach for enhancing Arabic question/answering. Special Issue in the International Journal on Information and Communication Technologies/IEEE. June.Abouenour, L., Bouzoubaa, K., & Rosso, P. (2010b). Using the YAGO ontology as a resource for the enrichment of named entities in Arabic WordNet. In Workshop LR & HLT for semitic languages, LREC’10. Malta. May, 2010.Ahonen-Myka, H. (2002). Discovery of frequent word sequences in text. In Proceedings of the ESF exploratory workshop on pattern detection and discovery (pp. 180–189). London, UK: Springer.Al Khalifa, M., & RodrĂ­guez, H. (2009). Automatically extending NE coverage of Arabic WordNet using Wikipedia. In Proceedings of the 3rd international conference on Arabic language processing CITALA’09, May, Rabat, Morocco.Alotaiby, F., Alkharashi, I., & Foda, S. (2009). Processing large Arabic text corpora: Preliminary analysis and results. In Proceedings of the second international conference on Arabic language resources and tools (pp. 78–82), Cairo, Egypt.Baker, C. F., Fillmore, C. J., & Cronin, B. (2003). The structure of the FrameNet database. International Journal of Lexicography, 16(3), 281–296.Baldwin, T., Pool, P., & Colowick, S. M. (2010). PanLex and LEXTRACT: Translating all words of all languages of the world. In Proceedings of Coling 2010, demonstration volume (pp. 37–40), Beijing.Benajiba, Y., Diab, M., & Rosso, P. (2009). Using language independent and language specific features to enhance Arabic named entity recognition. In IEEE transactions on audio, speech and language processing. Special Issue on Processing Morphologically Rich Languages, 17(5), 2009.Benajiba, Y., Rosso, P., & Lyhyaoui, A. (2007). Implementation of the ArabiQA question answering system’s components. In Proceedings of workshop on Arabic natural language processing, 2nd Information Communication Technologies int. symposium, ICTIS-2007, April 3–5, Fez, Morocco.BenoĂźt, S., & Darja, F. (2008). Building a free French WordNet from multilingual resources. Workshop on Ontolex 2008, LREC’08, June, Marrakech, Morocco.Black, W., Elkateb, S., Rodriguez, H, Alkhalifa, M., Vossen, P., Pease, A., et al. (2006). Introducing the Arabic WordNet project. In Proceedings of the third international WordNet conference. Sojka, Choi: Fellbaum & Vossen (eds).Boudelaa, S., & Gaskell, M. G. (2002). A reexamination of the default system for Arabic plurals. Language and Cognitive Processes, 17, 321–343.Brini, W., Ellouze & M., Hadrich, B. L. (2009a). QASAL: Un systĂšme de question-rĂ©ponse dĂ©diĂ© pour les questions factuelles en langue Arabe. In 9th JournĂ©es Scientifiques des Jeunes Chercheurs en GĂ©nie Electrique et Informatique, Tunisia.Brini, W., Trigui, O., Ellouze, M., Mesfar, S., Hadrich, L., & Rosso, P. (2009b). Factoid and definitional Arabic question answering system. In Post-proceedings of NOOJ-2009, June 8–10, Tozeur, Tunisia.Buscaldi, D., Rosso, P., GĂłmez, J. M., & Sanchis, E. (2010). Answering questions with an n-gram based passage retrieval engine. Journal of Intelligent Information Systems, 34(2), 113–134.Costa, R. P., & Seco, N. (2008). Hyponymy extraction and Web search behavior analysis based on query reformulation. In Proceedings of the 11th Ibero-American conference on AI: advances in artificial intelligence (pp. 1–10).Denicia-carral, C., Montes-y-GĂ”mez, M., Villaseñor-pineda, L., & Hernandez, R. G. (2006). A text mining approach for definition question answering. In Proceedings of the 5th international conference on natural language processing, FinTal’2006, Turku, Finland.Diab, M. T. (2004). Feasibility of bootstrapping an Arabic Wordnet leveraging parallel corpora and an English Wordnet. In Proceedings of the Arabic language technologies and resources, NEMLAR, Cairo, Egypt.El Amine, M. A. (2009). Vers une interface pour l’enrichissement des requĂȘtes en arabe dans un systĂšme de recherche d’information. In Proceedings of the 2nd confĂ©rence internationale sur l’informatique et ses applications (CIIA’09), May 3–4, Saida, Algeria.Elghamry, K. (2008). Using the web in building a corpus-based hypernymy-hyponymy Lexicon with hierarchical structure for Arabic. In Proceedings of the 6th international conference on informatics and systems, INFOS 2008. Cairo, Egypt.Elkateb, S., Black, W., Vossen, P., Farwell, D., RodrĂ­guez, H., Pease, A., et al. (2006). Arabic WordNet and the challenges of Arabic. In Proceedings of Arabic NLP/MT conference, London, UK.Fellbaum, C. (Ed.). (1998). WordNet: An electronic lexical database. MA: MIT Press.GarcĂ­a-Blasco, S., Danger, R., & Rosso, P. (2010). Drug–drug interaction detection: A new approach based on maximal frequent sequences. Sociedad Española para el Procesamiento del Lenguaje Natural, SEPLN, 45, 263–266.GarcĂ­a-HernĂĄndez, R. A. (2007). Algoritmos para el descubrimiento de patrones secuenciales maximales. Ph.D. Thesis, INAOE. September, Mexico.GarcĂ­a-HernĂĄndez, R. A., MartĂ­nez Trinidad, J. F., & Carrasco-ochoa, J. A. (2010). Finding maximal sequential patterns in text document collections and single documents. Informatica, 34(1), 93–101.Goweder, A., & De Roeck, A. (2001). Assessment of a significant Arabic corpus. In Proceedings of the Arabic NLP workshop at ACL/EACL, (pp. 73–79), Toulouse, France.Graff, D. (2007). Arabic Gigaword (3rd ed.). Philadelphia, USA: Linguistic Data Consortium.Graff, D., Kong, J., Chen, K., & Maeda, K. (2007). English Gigaword (3rd ed.). Philadelphia, USA: Linguistic Data Consortium.Hammou, B., Abu-salem, H., Lytinen, S., & Evens, M. (2002). QARAB: A question answering system to support the Arabic language. In Proceedings of the workshop on computational approaches to Semitic languages, ACL, (pp. 55–65), Philadelphia.Hearst, M. A. (1992). Automatic acquisition of hyponyms from large text corpora. In Proceedings of the 14th conference on Computational linguistics, COLING ‘92 (vol. 2, pp. 539–545).Kanaan, G., Hammouri, A., Al-Shalabi, R., & Swalha, M. (2009). A new question answering system for the Arabic language. American Journal of Applied Sciences, 6(4), 797–805.Kim, H., Chen, S., & Veale, T. (2006). Analogical reasoning with a synergy of HowNet and WordNet. In Proceedings of GWC’2006, the 3rd global WordNet conference, January, Cheju, Korea.Kipper-Schuler, K. (2006). VerbNet: A broad-coverage, comprehensive verb lexicon. Ph.D. Thesis.Mohammed, F. A., Nasser, K., & Harb, H. M. (1993). A knowledge-based Arabic question answering system (AQAS). In ACM SIGART bulletin (pp. 21–33).Niles, I., & Pease, A. (2001). Towards a standard upper ontology. In Proceedings of FOIS-2 (pp. 2–9), Ogunquit, Maine.Niles, I., & Pease, A. (2003). Linking lexicons and ontologies: Mapping WordNet to the suggested upper merged ontology. In Proceedings of the 2003 international conference on information and knowledge engineering, Las Vegas, Nevada.Ortega-Mendoza, R. M., Villaseñor-pineda, L., & Montes-y-GĂ”mez, M. (2007). Using lexical patterns to extract hyponyms from the Web. In Proceedings of the Mexican international conference on artificial intelligence MICAI 2007. November, Aguascalientes, Mexico. Lecture Notes in Artificial Intelligence 4827. Berlin: Springer.Palmer, M., P. Kingsbury, & D. Gildea. (2005). The proposition bank: An annotated corpus of semantic roles. Computational Linguistics, 21. USA: MIT Press.Pantel, P., & Pennacchiotti, M. (2006). Espresso: Leveraging generic patterns for automatically harvesting semantic relations. In Proceedings of conference on computational linguistics association for computational linguistics, (pp. 113–120), Sydney, Australia.Rodriguez, H., Farwell, D., Farreres, J., Bertran, M., Alkhalifa, M., & MartĂ­, A. (2008a). Arabic WordNet: Semi-automatic extensions using Bayesian Inference. In Proceedings of the the 6th conference on language resources and evaluation LREC2008, May, Marrakech, Morocco.Rodriguez, H., Farwell, D., Farreres, J., Bertran, M., Alkhalifa, M., Mart., M., et al. (2008b). Arabic WordNet: Current state and future extensions. In Proceedings of the fourth global WordNet conference, January 22–25, Szeged, Hungary.Sharaf, A. M. (2009). The Qur’an annotation for text mining. First year transfer report. School of Computing, Leeds University. December.Snow, R., Jurafsky, D., & Andrew, Y. N. (2005). Learning syntactic patterns for automatic hypernym discovery. In Lawrence K. Saul et al. (Eds.), Advances in neural information processing systems, 17. Cambridge, MA: MIT Press.Suchanek, F. M., Kasneci, G., & Weikum, G. (2007). YAGO: A core of semantic knowledge unifying WordNet and Wikipedia. In Proceedings of 16th international World Wide Web conference WWW’2007, (pp. 697–706), May, Banff, Alberta, Canada: ACM Press.Tjong Kim Sang, E., & Hofmann, K. (2007). Automatic extraction of Dutch hypernym–hyponym pairs. In Proceedings of CLIN-2006, Leuven, Belgium.Toral, A., Munoz, R., & Monachini, M. (2008). Named entity WordNet. In Proceedings of the Sixth international conference on language resources and evaluation (LREC’08), Marrakech, Morocco.Vossen, P. (Ed.). (1998). EuroWordNet, a multilingual database with lexical semantic networks. The Netherlands: Kluwer.Wagner, A. (2005). Learning thematic role relations for lexical semantic nets. Ph.D. Thesis, University of TĂŒbingen, 2005

    A Selberg integral for the Lie algebra A_n

    Full text link
    A new q-binomial theorem for Macdonald polynomials is employed to prove an A_n analogue of the celebrated Selberg integral. This confirms the g=A_n case of a conjecture by Mukhin and Varchenko concerning the existence of a Selberg integral for every simple Lie algebra g.Comment: 32 page

    Inductively guided circuits for ultracold dressed atoms

    Get PDF
    Recent progress in optics, atomic physics and material science has paved the way to study quantum effects in ultracold atomic alkali gases confined to non-trivial geometries. Multiply connected traps for cold atoms can be prepared by combining inhomogeneous distributions of DC and radio-frequency electromagnetic fields with optical fields that require complex systems for frequency control and stabilization. Here we propose a flexible and robust scheme that creates closed quasi-one-dimensional guides for ultracold atoms through the ‘dressing’ of hyperfine sublevels of the atomic ground state, where the dressing field is spatially modulated by inductive effects over a micro-engineered conducting loop. Remarkably, for commonly used atomic species (for example, 7Li and 87Rb), the guide operation relies entirely on controlling static and low-frequency fields in the regimes of radio-frequency and microwave frequencies. This novel trapping scheme can be implemented with current technology for micro-fabrication and electronic control

    A critical review of PASBio's argument structures for biomedical verbs

    Get PDF
    BACKGROUND: Propositional representations of biomedical knowledge are a critical component of most aspects of semantic mining in biomedicine. However, the proper set of propositions has yet to be determined. Recently, the PASBio project proposed a set of propositions and argument structures for biomedical verbs. This initial set of representations presents an opportunity for evaluating the suitability of predicate-argument structures as a scheme for representing verbal semantics in the biomedical domain. Here, we quantitatively evaluate several dimensions of the initial PASBio propositional structure repository. RESULTS: We propose a number of metrics and heuristics related to arity, role labelling, argument realization, and corpus coverage for evaluating large-scale predicate-argument structure proposals. We evaluate the metrics and heuristics by applying them to PASBio 1.0. CONCLUSION: PASBio demonstrates the suitability of predicate-argument structures for representing aspects of the semantics of biomedical verbs. Metrics related to theta-criterion violations and to the distribution of arguments are able to detect flaws in semantic representations, given a set of predicate-argument structures and a relatively small corpus annotated with them

    Serious sports-related injury in England and Wales from 2012-2017: a study protocol

    Get PDF
    Background Physical activity is an important component of healthy lifestyles, with a central role in morbidity prevention. However, sporting and physical activity also involve an inherent injury risk. Some sports and activities have a higher injury risk, and may involve more severe injuries. Furthermore, injuries of a severe nature have substantial individual and societal consequences, including the burden of assessment, treatment, and potential on-going care costs. There are limited data on severe sports injury risk in England and Wales, and no national data describing risk across sports. The aims of this study are to identify the cases and incidence of: i) paediatric and ii) adult severe sports injury from 2012 to 2017; and to describe injury incidence in individual sports. Methods This study is an analysis of prospectively collected sport-related injuries, treated from January 2012 to December 2017. Incidents involving a severe injury (in-patient trauma care) in England and Wales, will be identified from the Trauma Audit Research Network registry. Data for patients who were: transfers or direct hospital admissions, with inpatient stays of ≄3 days, admissions to High Dependency areas, or in-hospital mortality after admission; and whose injury mechanism was sport, or incident description included one of 62 sporting activities, will be extracted. Data will be categorised by sport, and sports participation data will be derived from Sport England participation surveys. Descriptive statistics will be estimated for all demographic, incident, treatment and sport fields, and crude serious annual injury incidence proportions estimated. Poisson confidence intervals will be estimated for each sport and used to describe injury risk (incidence) across sporting activities. Discussion This study will be the first to describe the number of, and trends in severe sport-related injuries in England and Wales. These data are useful to monitor the number and burden of severe sports injury, and inform injury prevention efforts. The monitoring and mitigation of sports injury risk is essential for individuals, health services and policy, and to encourage physically active lifestyles and safer participation for adults and children

    Evaluation of an interactive, case-based review session in teaching medical microbiology

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Oklahoma State University-Center for Health Sciences (OSU-CHS) has replaced its microbiology wet laboratory with a variety of tutorials including a case-based interactive session called Microbial Jeopardy!. The question remains whether the time spent by students and faculty in the interactive case-based tutorial is worthwhile? This study was designed to address this question by analyzing both student performance data and assessing students' perceptions regarding the tutorial.</p> <p>Methods</p> <p>Both quantitative and qualitative data were used in the current study. Part One of the study involved assessing student performance using archival records of seven case-based exam questions used in the 2004, 2005, 2006, and 2007 OSU-CHS Medical Microbiology course. Two sample t-tests for proportions were used to test for significant differences related to tutorial usage. Part Two used both quantitative and qualitative means to assess student's perceptions of the Microbial Jeopardy! session. First, a retrospective survey was administered to students who were enrolled in Medical Microbiology in 2006 or 2007. Second, responses to open-ended items from the 2008 course evaluations were reviewed for comments regarding the Microbial Jeopardy! session.</p> <p>Results</p> <p>Both student performance and student perception data support continued use of the tutorials. Quantitative and qualitative data converge to suggest that students like and learn from the interactive, case-based session.</p> <p>Conclusion</p> <p>The case-based tutorial appears to improve student performance on case-based exam questions. Additionally, students perceived the tutorial as helpful in preparing for exam questions and reviewing the course material. The time commitment for use of the case-based tutorial appears to be justified.</p

    Binding of Transcription Factor GabR to DNA Requires Recognition of DNA Shape at a Location Distinct from its Cognate Binding Site

    Get PDF
    Mechanisms for transcription factor recognition of specific DNA base sequences are well characterized and recent studies demonstrate that the shape of these cognate binding sites is also important. Here, we uncover a new mechanism where the transcription factor GabR simultaneously recognizes two cognate binding sites and the shape of a 29 bp DNA sequence that bridges these sites. Small-angle X-ray scattering and multi-angle laser light scattering are consistent with a model where the DNA undergoes a conformational change to bend around GabR during binding. In silico predictions suggest that the bridging DNA sequence is likely to be bendable in one direction and kinetic analysis of mutant DNA sequences with biolayer interferometry, allowed the independent quantification of the relative contribution of DNA base and shape recognition in the GabR–DNA interaction. These indicate that the two cognate binding sites as well as the bendability of the DNA sequence in between these sites are required to form a stable complex. The mechanism of GabR–DNA interaction provides an example where the correct shape of DNA, at a clearly distinct location from the cognate binding site, is required for transcription factor binding and has implications for bioinformatics searches for novel binding sites

    Protein structure and phenotypic analysis of pathogenic and population missense variants inSTXBP1.

    Get PDF
    This is the final version of the article. Available from Wiley via the DOI in this record.BACKGROUND: Syntaxin-binding protein 1, encoded bySTXBP1, is highly expressed in the brain and involved in fusing synaptic vesicles with the plasma membrane. Studies have shown that pathogenic loss-of-function variants in this gene result in various types of epilepsies, mostly beginning early in life. We were interested to model pathogenic missense variants on the protein structure to investigate the mechanism of pathogenicity and genotype-phenotype correlations. METHODS: We report 11 patients with pathogenic de novo mutations inSTXBP1identified in the first 4293 trios of the Deciphering Developmental Disorder (DDD) study, including six missense variants. We analyzed the structural locations of the pathogenic missense variants from this study and the literature, as well as population missense variants extracted from Exome Aggregation Consortium (ExAC). RESULTS: Pathogenic variants are significantly more likely to occur at highly conserved locations than population variants, and be buried inside the protein domain. Pathogenic mutations are also more likely to destabilize the domain structure compared with population variants, increasing the proportion of (partially) unfolded domains that are prone to aggregation or degradation. We were unable to detect any genotype-phenotype correlation, but unlike previously reported cases, most of the DDD patients withSTXBP1pathogenic variants did not present with very early-onset or severe epilepsy and encephalopathy, though all have developmental delay with intellectual disability and most display behavioral problems and suffered seizures in later childhood. CONCLUSION: Variants acrossSTXBP1that cause loss of function can result in severe intellectual disability with or without seizures, consistent with a haploinsufficiency mechanism. Pathogenic missense mutations act through destabilization of the protein domain, making it prone to aggregation or degradation. The presence or absence of early seizures may reflect ascertainment bias in the literature as well as the broad recruitment strategy of the DDD study.This study was supported by the Health Innovation Challenge Fund (grant number: HICF-1009-003) and Wellcome Trust Sanger Institute (grant number: WT098051)
    • 

    corecore