2,391 research outputs found

    Vertex Representations for Yangians of Kac-Moody algebras

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    30 pagesUsing vertex operators, we build representations of the Yangian of a simply laced Kac-Moody algebra and of its double. As a corollary, we prove the PBW property for simply laced affine Yangians.Peer reviewe

    Factors Influencing the Surprising Instability of Word Embeddings

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    Despite the recent popularity of word embedding methods, there is only a small body of work exploring the limitations of these representations. In this paper, we consider one aspect of embedding spaces, namely their stability. We show that even relatively high frequency words (100-200 occurrences) are often unstable. We provide empirical evidence for how various factors contribute to the stability of word embeddings, and we analyze the effects of stability on downstream tasks.Comment: NAACL HLT 201

    The formal shift operator on the Yangian double

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    Let g\mathfrak{g} be a symmetrizable Kac-Moody algebra with associated Yangian YgY_\hbar\mathfrak{g} and Yangian double DYg\mathrm{D}Y_\hbar\mathfrak{g}. An elementary result of fundamental importance to the theory of Yangians is that, for each cCc\in \mathbb{C}, there is an automorphism τc\tau_c of YgY_\hbar\mathfrak{g} corresponding to the translation tt+ct\mapsto t+c of the complex plane. Replacing cc by a formal parameter zz yields the so-called formal shift homomorphism τz\tau_z from YgY_\hbar\mathfrak{g} to the polynomial algebra Yg[z]Y_\hbar\mathfrak{g}[z]. We prove that τz\tau_z uniquely extends to an algebra homomorphism Φz\Phi_z from the Yangian double DYg\mathrm{D}Y_\hbar\mathfrak{g} into the \hbar-adic closure of the algebra of Laurent series in z1z^{-1} with coefficients in the Yangian YgY_\hbar\mathfrak{g}. This induces, via evaluation at any point cC×c\in \mathbb{C}^\times, a homomorphism from DYg\mathrm{D}Y_\hbar\mathfrak{g} into the completion of the Yangian with respect to its grading. We show that each such homomorphism gives rise to an isomorphism between completions of DYg\mathrm{D}Y_\hbar\mathfrak{g} and YgY_\hbar\mathfrak{g} and, as a corollary, we find that the Yangian YgY_\hbar\mathfrak{g} can be realized as a degeneration of the Yangian double DYg\mathrm{D}Y_\hbar\mathfrak{g}. Using these results, we obtain a Poincar\'{e}-Birkhoff-Witt theorem for DYg\mathrm{D}Y_\hbar\mathfrak{g} applicable when g\mathfrak{g} is of finite type or of simply-laced affine type.Comment: 40 page

    Examination of the Association Between Intimate Partner Violence and STI/HIV Risk in African American Women in High Risk Areas of Atlanta, GA: A Mixed Methods Analysis

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    In March 2012, President Obama issued a Presidential Memorandum creating an interagency Federal Working Group to explore the intersection of HIV/AIDS, violence against women and girls, and gender-related health disparities. Intimate partner violence (IPV) and HIV constitute major public health issues for women, particularly African American women who are disproportionately affected by HIV/AIDS. In 2012, the rate of HIV for African American women was four to 20 times higher than rates for females of other races. This study explores the complex relationship between IPV and STI/HIV risk in African American females. In an attempt to examine the intersection of IPV and STI/HIV risk this study used cross-sectional survey data to quantitatively examine the differences between women who had experienced IPV in the previous 12 months (cases) and women who had not experienced IPV in the previous 12 months (controls) in: 1) previous STI diagnosis, 2) accessing HIV testing and 3) mean scores of fear of condom negotiation due to physical violence. Chi-square analyses were completed to determine if the populations were statistically significant in terms of previous STI diagnosis and accessing HIV testing. An independent-samples t-test was conducted to compare the fear of condom negotiation scores for cases and controls. In addition, qualitative analysis was conducted to further elucidate the mechanisms from experiencing IPV to an increased risk of HIV infection. The quantitative analysis suggests a significant difference between fear of condom negotiation due to fear of physical violence. The qualitative analysis suggests that women who experience IPV are often forced to have sex with their partners, experience physical violence in response to condom negotiation and use drugs and/or alcohol to cope with the abuse. HIV prevention interventions need to address IPV as a possible risk factor. In addition, an enhancement of IPV screening in healthcare settings is needed. Future prospective studies are critical to address the issues of temporality and causality

    Experimental investigations concerning the limits of detonation in gaseous mixtures. Part I

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    It is the purpose of this investigation to determine quantitatively the limits of detonation in gaseous mixtures for the conditions imposed and for a number of given gaseous explosive mixtures

    Texan City magazine health news : a content analysis

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    City magazines have a powerful role in convincing readers to take proactive health measures, however they rarely take advantage of their capacity to set their communities' public agendas. This study considered the health content in five city magazines in Texas: Austin Monthly, D Magazine, Fort Worth, Texas Magazine, Houstonia, and San Antonio Magazine. Using agenda building, agenda-setting, and second-level agenda-setting, this research quantitatively analyzed 169 health articles published in 2018 on the five magazines' websites for how the publications presented health news. The core findings of this research included: the overall agenda was actionable health, the city magazines were more than three times more likely to cite an indirect source than a human, and that salient story elements promoted the historical status quo of city magazines and not the health agenda or health literacy. The most prevalent story topic was nutrition/fitness, occurring in the majority of the articles. The core of my research was to question whether these publications were publishing health content that reflected their cities' health profiles. While some magazines, such as Houstonia and Fort Worth, Texas Magazine did better than others, all of the city magazines could improve.by Catherine WendlandtIncludes bibliographical reference
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