1,807 research outputs found

    Musculoskeletal adaptations to physical interventions in spinal cord injury

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    Adjacency Pair Recognition in Wikipedia Discussions using Lexical Pairs

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    Needle in a Haystack: Reducing the Costs of Annotating Rare-Class Instances in Imbalanced Datasets

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    Anomalies, Unparticles, and Seiberg Duality

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    We calculate triangle anomalies for fermions with non-canonical scaling dimensions. The most well known example of such fermions (aka unfermions) occurs in Seiberg duality where the matching of anomalies (including mesinos with scaling dimensions between 3/2 and 5/2) is a crucial test of duality. By weakly gauging the non-local action for an unfermion, we calculate the one-loop three-current amplitude. Despite the fact that there are more graphs with more complicated propagators and vertices, we find that the calculation can be completed in a way that nearly parallels the usual case. We show that the anomaly factor for fermionic unparticles is independent of the scaling dimension and identical to that for ordinary fermions. This can be viewed as a confirmation that unparticle actions correctly capture the physics of conformal fixed point theories like Banks-Zaks or SUSY QCD.Comment: 13 pages, 1 figur

    Convergence science in the Anthropocene: Navigating the known and unknown

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    Rapidly changing ecological and social systems currently pose significant societal challenges. Navigating the complexity of social-ecological change requires ap- proaches able to cope with, and potentially solve, both foreseen and unforeseen societal challenges. The emergent field of convergence addresses the intricacies of such challenges, and is thus relevant to a broad range of interdisciplinary issues. This paper suggests a way to conceptualize convergence research. It discusses how it relates to two major societal challenges (adaptation, transformation), and to the generation of policy-relevant science. It also points out limitations to the further development of convergence research

    Crowdsource Annotation and Automatic Reconstruction of Online Discussion Threads

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    Modern communication relies on electronic messages organized in the form of discussion threads. Emails, IMs, SMS, website comments, and forums are all composed of threads, which consist of individual user messages connected by metadata and discourse coherence to messages from other users. Threads are used to display user messages effectively in a GUI such as an email client, providing a background context for understanding a single message. Many messages are meaningless without the context provided by their thread. However, a number of factors may result in missing thread structure, ranging from user mistake (replying to the wrong message), to missing metadata (some email clients do not produce/save headers that fully encapsulate thread structure; and, conversion of archived threads from over repository to another may also result in lost metadata), to covert use (users may avoid metadata to render discussions difficult for third parties to understand). In the field of security, law enforcement agencies may obtain vast collections of discussion turns that require automatic thread reconstruction to understand. For example, the Enron Email Corpus, obtained by the Federal Energy Regulatory Commission during its investigation of the Enron Corporation, has no inherent thread structure. In this thesis, we will use natural language processing approaches to reconstruct threads from message content. Reconstruction based on message content sidesteps the problem of missing metadata, permitting post hoc reorganization and discussion understanding. We will investigate corpora of email threads and Wikipedia discussions. However, there is a scarcity of annotated corpora for this task. For example, the Enron Emails Corpus contains no inherent thread structure. Therefore, we also investigate issues faced when creating crowdsourced datasets and learning statistical models of them. Several of our findings are applicable for other natural language machine classification tasks, beyond thread reconstruction. We will divide our investigation of discussion thread reconstruction into two parts. First, we explore techniques needed to create a corpus for our thread reconstruction research. Like other NLP pairwise classification tasks such as Wikipedia discussion turn/edit alignment and sentence pair text similarity rating, email thread disentanglement is a heavily class-imbalanced problem, and although the advent of crowdsourcing has reduced annotation costs, the common practice of crowdsourcing redundancy is too expensive for class-imbalanced tasks. As the first contribution of this thesis, we evaluate alternative strategies for reducing crowdsourcing annotation redundancy for class-imbalanced NLP tasks. We also examine techniques to learn the best machine classifier from our crowdsourced labels. In order to reduce noise in training data, most natural language crowdsourcing annotation tasks gather redundant labels and aggregate them into an integrated label, which is provided to the classifier. However, aggregation discards potentially useful information from linguistically ambiguous instances. For the second contribution of this thesis, we show that, for four of five natural language tasks, filtering of the training dataset based on crowdsource annotation item agreement improves task performance, while soft labeling based on crowdsource annotations does not improve task performance. Second, we investigate thread reconstruction as divided into the tasks of thread disentanglement and adjacency recognition. We present the Enron Threads Corpus, a newly-extracted corpus of 70,178 multi-email threads with emails from the Enron Email Corpus. In the original Enron Emails Corpus, emails are not sorted by thread. To disentangle these threads, and as the third contribution of this thesis, we perform pairwise classification, using text similarity measures on non-quoted texts in emails. We show that i) content text similarity metrics outperform style and structure text similarity metrics in both a class-balanced and class-imbalanced setting, and ii) although feature performance is dependent on the semantic similarity of the corpus, content features are still effective even when controlling for semantic similarity. To reconstruct threads, it is also necessary to identify adjacency relations among pairs. For the forum of Wikipedia discussions, metadata is not available, and dialogue act typologies, helpful for other domains, are inapplicable. As our fourth contribution, via our experiments, we show that adjacency pair recognition can be performed using lexical pair features, without a dialogue act typology or metadata, and that this is robust to controlling for topic bias of the discussions. Yet, lexical pair features do not effectively model the lexical semantic relations between adjacency pairs. To model lexical semantic relations, and as our fifth contribution, we perform adjacency recognition using extracted keyphrases enhanced with semantically related terms. While this technique outperforms a most frequent class baseline, it fails to outperform lexical pair features or tf-idf weighted cosine similarity. Our investigation shows that this is the result of poor word sense disambiguation and poor keyphrase extraction causing spurious false positive semantic connections. In concluding this thesis, we also reflect on open issues and unanswered questions remaining after our research contributions, discuss applications for thread reconstruction, and suggest some directions for future work

    Measuring the measurement error: A method to qualitatively validate survey data

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    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Empirical social science relies heavily on self-reported data, but subjects may misreport behaviors, especially sensitive ones such as crime or drug abuse. If a treatment influences survey misreporting, it biases causal estimates. We develop a validation technique that uses intensive qualitative work to assess survey misreporting and pilot it in a field experiment where subjects were assigned to receive cash, therapy, both, or neither. According to survey responses, both treatments reduced crime and other sensitive behaviors. Local researchers spent several days with a random subsample of subjects after surveys, building trust and obtaining verbal confirmation of four sensitive behaviors and two expenditures. In this instance, validation showed survey underreporting of most sensitive behaviors was low and uncorrelated with treatment, while expenditures were under reported in the survey across all arms, but especially in the control group. We use these data to develop measurement error bounds on treatment effects estimated from surveys.This study was funded by the National Science Foundation (SES-1317506), the World Bank's Learning on Gender and Conflict in Africa (LOGiCA) trust fund, the World Bank's Italian Children and Youth (CHYAO) trust fund, the Department of International Development, UK (DFID, GA-C1-RA2-114) via the Institute for the Study of Labor (IZA), a Vanguard Charitable Trust, the American People through the United States Agency for International Development (USAID, AID-OAA-A-12-00066) DCHA/CMM office, and the Robert Wood Johnson Health and Society Scholars Program at Harvard University (Cohort 5). The contents of this study are the sole responsibility of authors and do not necessarily reflect the views of their employers or any of these funding agencies or governments

    Comprehensive Chronic Pain Treatment: Does Smoking Affect Outcomes?

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    Abstract Objective: To determine whether smoking status effects pain and functional outcomes in a chronic pain program. Methods: A retrospective cohort study of 178 patients treated at the Nebraska Medicine comprehensive Pain Management Program over a five year period was completed. Outcomes measures were the Visual Analog Scale Past Month Average Pain score (VAS-PMA), Multidimensional Pain Inventory pain and interference scales (MPI-P and MPI-I), and the Pain and Impairment Relationship Scale (PAIRS). Patients were categorized by smoking status into non-smoker or current smoker groups. Wilcoxon tests were used to compare the pre scores, post scores, and post-minus-pre scores between smoking status groups. Results: The pre-treatment VAS-PMA and MPI-P median scores were significantly higher in the current smoker group (81.5 and 5.0, respectively) compared to the non-smoker group (76.5 and 4.3, respectively), whereas post-treatment median scores did not differ. Furthermore, the current smoker group had a significantly greater decrease on the MPI-P from pre- to post-treatment (median=-2.0) than the non-smoker group (median=-1.6). In addition, smokers had a significantly higher pre-treatment PAIRS score (73.5) than nonsmokers (70), whereas post-treatment scores did not differ. Conclusion: Smokers and non-smokers both benefit from the program, but smokers, who report greater initial pain and stronger beliefs about the association between pain and functional impairment, may benefit more than non-smokers
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