2,023 research outputs found

    Quantitative computational syntax: some initial results

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    In the computational study of human intelligence, the language sciences are in the unique position of resting both on sophisticated theories and representations and on large amounts of observational data available for many languages. In this paper, we discuss some recent results, where large-scale, data-intensive computational modelling techniques are used to address fundamental linguistic questions on the quantitative properties of abstract grammatical representations. Specifically, we present a programme of research exemplified in three case studies to identify the causes of frequency differentials. In the area of word order, we discuss work that investigates whether typological and corpus frequencies are systematically correlated to abstract syntactic structures and to higher-level structural principles of minimisation and efficiency. In the area of verb meaning, corpus-based computational models are discussed that investigate how frequencies are correlated to well-known lexical effects in causative alternations and morphological marking. The large corpus-based, cross-linguistic component of the work and the abstract grammatical hypotheses on word order and verb meaning provide new empirical and computational evidence to the important debate on language variation, its extent and its limits and illustrate how to bring corpus-based computational methodology to bear on theoretical syntactic issues. In so doing, we help reduce the current gap between theoretical and computational linguistics

    Learning Document Similarity Using Natural Language Processing

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    The recent considerable growth in the amount of easily available on-line text has brought to the foreground the need for large-scale natural language processing tools for text data mining. In this paper we address the problem of organizing documents into meaningful groups according to their content and to visualize a text collection, providing an overview of the range of documents and of their relationships, so that they can be browsed more easily. We use Self-Organizing Maps (SOMs) (Kohonen 1984). Great efficiency challenges arise in creating these maps. We study linguistically-motivated ways of reducing the representation of a document to increase efficiency and ways to disambiguate the words in the documents

    Drug conjugation to hyaluronan widens therapeutic indications for ovarian cancer

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    Management of ovarian cancer still requires improvements in therapeutic options. A drug delivery strategy was tested that allows specific targeting of tumor cells in combination with a controlled release of a cytotoxic molecule. To this aim, the efficacy of a loco-regional intraperitoneal treatment with a bioconjugate (ONCOFID-S) derived by chemical linking of SN-38, the active metabolite of irinotecan (CPT-11), to hyaluronan was assessed in a mouse model of ovarian carcinomatosis. In vitro, the bioconjugate selectively interacted with ovarian cancer cells through the CD44 receptor, disclosed a dose-dependent tumor growth inhibition efficacy comparable to that of free SN-38 drug, and inhibited Topoisomerase I function leading to apoptosis by a mechanism involving caspase-3 and -7 activation and PARP cleavage. In vivo, the intraperitoneal administration of ONCOFID-S in tumor-bearing mice did not induce inflammation, and evidenced an improved therapeutic efficacy compared with CPT-11. In conclusion, SN-38 conjugation to hyaluronan significantly improved the profile of in vivo tolerability and widened the field of application of irinotecan. Therefore, this approach can be envisaged as a promising therapeutic strategy for loco-regional treatment of ovarian cancer

    Exploiting Cloze Questions for Few Shot Text Classification and Natural Language Inference

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    Some NLP tasks can be solved in a fully unsupervised fashion by providing a pretrained language model with “task descriptions” in natural language (e.g., Radford et al., 2019). While this approach underperforms its supervised counterpart, we show in this work that the two ideas can be combined: We introduce Pattern-Exploiting Training (PET), a semi-supervised training procedure that reformulates input examples as cloze-style phrases to help language models understand a given task. These phrases are then used to assign soft labels to a large set of unlabeled examples. Finally, standard supervised training is performed on the resulting training set. For several tasks and languages, PET outperforms supervised training and strong semi-supervised approaches in low-resource settings by a large margin

    The Scope and the Sources of Variation in Verbal Predicates in English and French

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    Proceedings of the Ninth International Workshop on Treebanks and Linguistic Theories. Editors: Markus Dickinson, Kaili Müürisep and Marco Passarotti. NEALT Proceedings Series, Vol. 9 (2010), 199-210. © 2010 The editors and contributors. Published by Northern European Association for Language Technology (NEALT) http://omilia.uio.no/nealt . Electronically published at Tartu University Library (Estonia) http://hdl.handle.net/10062/15891

    Mandibular repositioning in adult patients - an alternative to surgery?: A two-year follow-up

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    Abstract Background Adult patients presenting with skeletal discrepancies may refuse surgical intervention. Materials and methods Thirty-two patients who declined orthognathic correction of their maxillo-mandibular dysplasia and who were without signs of temporomandibular dysfunction (TMD) were offered mandibular repositioning as a non-invasive alternative. Simulating a skeletal correction, it was explained that the approach was based on results described in case reports. Before commencing treatment, initial records, lateral and frontal head films, study casts and photos were obtained (T0) and the mandible was repositioned to camouflage a retrognathic skeletal discrepancy or a mandibular transverse asymmetry by means of an occlusal build-up using Triad™ gel. Results Three months later (T1), 23 patients had adapted to the new occlusion reflected by an absence of functional disturbance and without fracture of the composite occlusal build-up. Mandibular position in these patients was maintained by additional orthodontic treatment and an adjustment of the occlusion to the built-up postured position (T1). The skeletal changes occurring during repositioning were assessed on sagittal and frontal head films while intra-articular changes occurring during a two-year follow-up period (T2) were evaluated on images constructed from CBCT scans. No significant change, either in the direction of relapse or in the direction of further normalisation of condylar position, were observed during the two-year observation period. Conclusion Mandibular repositioning is a non-invasive intervention that may be considered a valid alternative to surgery in selected patients. Morphological variables from the radiographs taken at T0 and the results of the initial clinical evaluation of dysfunction yielded only vague and insignificant indicators regarding the predictability of the adaptation. A CBCT scan at T0 might have contributed to the identification of the patients who would likely accept the repositioning

    Does He Wink or Does He Nod? A Challenging Benchmark for Evaluating Word Understanding of Language Models

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    Recent progress in pretraining language models on large corpora has resulted in significant performance gains on many NLP tasks. These large models acquire linguistic knowledge during pretraining, which helps to improve performance on downstream tasks via fine-tuning. To assess what kind of knowledge is acquired, language models are commonly probed by querying them with ‘fill in the blank’ style cloze questions. Existing probing datasets mainly focus on knowledge about relations between words and entities. We introduce WDLMPro (Word Definitions Language Model Probing) to evaluate word understanding directly using dictionary definitions of words. In our experiments, three popular pretrained language models struggle to match words and their definitions. This indicates that they understand many words poorly and that our new probing task is a difficult challenge that could help guide research on LMs in the future

    Reverse immunoediting: When immunity is edited by antigen

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    Immune selective pressure occurring during cancer immunoediting shapes tumor features revealed at clinical presentation. However, in the "Escape" phase, the tumor itself has the chance to influence the immunological response. Therefore, the capacity of the immune response to sculpt the tumor characteristics is only one side of the coin and even the opposite is likely true, i.e. that an antigen can shape the immune response in a sort of "reverse immunoediting". This reciprocal modeling probably occurs continuously, whenever the immune system encounters a tumor/foreign antigen, and can be operative in the pathogen/immune system interplay, thus possibly permeating the protective immunity as a whole. In line with this view, the characterization of a T cell response as well as the design of both active and passive immunotherapy strategies should also take into account all Ag features (type, load and presentation). Overall, we suggest that the "reverse immunoediting" hypothesis could help to dissect the complex interplay between antigens and the immune repertoire, and to improve the outcome of immunotherapeutic approaches, where T cell responses are manipulated and reprogrammed

    Impact of γ-chain cytokines on EBV-specific T cell cultures

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    <p>Abstract</p> <p>Background</p> <p>Recent preclinical adoptive immunotherapy studies in murine models prompt to employ "proper" rather than "as many as possible" antigen-specific T cells to gain better therapeutic results. Ideally, "proper" T cells are poorly differentiated <it>in vitro</it>, but retain the capacity to fully differentiate into effector cells <it>in vivo</it>, where they can undergo long-term survival and strong proliferation. Such requirements can be achieved by modifying culture conditions, namely using less "differentiating" cytokines than IL-2.</p> <p>Methods</p> <p>To evaluate this issue in human T cell cultures, we exploited a well characterized and clinical-grade protocol finalized at generating EBV-specific CTL for adoptive immunotherapy. In particular, we studied the impact of IL-7, IL-15 and IL-21 compared to IL-2 on different aspects of T cell functionality, namely growth kinetics, differentiation/activation marker expression, cytokine production, and short-term and long-term cytotoxicity.</p> <p>Results</p> <p>Results disclosed that the culture modifications we introduced in the standard protocol did not improve activity nor induce substantial changes in differentiation marker expression of EBV-specific CTL.</p> <p>Conclusions</p> <p>Our data indicated that the addition of γ-chain cytokines other than IL-2 for the generation of EBV-specific T cell cultures did not produce the improvements expected on the basis of recent published literature. This fact was likely due to the intrinsic differences between murine and human models and highlights the need to design <it>ad hoc </it>protocols rather than simply modify the cytokines added in culture.</p
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