A study of the translation of sentiment in user-generated text

A thesis submitted in partial ful filment of the requirements of the University of Wolverhampton for the degree of Doctor of Philosophy.Emotions are biological states of feeling that humans may verbally express to communicate their negative or positive mood, influence others, or even afflict harm. Although emotions such as anger, happiness, affection, or fear are supposedly universal experiences, the lingual realisation of the emotional experience may vary in subtle ways across different languages. For this reason, preserving the original sentiment of the source text has always been a challenging task that draws in a translator's competence and fi nesse. In the professional translation industry, an incorrect translation of the sentiment-carrying lexicon is considered a critical error as it can be either misleading or in some cases harmful since it misses the fundamental aspect of the source text, i.e. the author's sentiment. Since the advent of Neural Machine Translation (NMT), there has been a tremendous improvement in the quality of automatic translation. This has lead to an extensive use of NMT online tools to translate User-Generated Text (UGT) such as reviews, tweets, and social media posts, where the main message is often the author's positive or negative attitude towards an entity. In such scenarios, the process of translating the user's sentiment is entirely automatic with no human intervention, neither for post-editing nor for accuracy checking. However, NMT output still lacks accuracy in some low-resource languages and sometimes makes critical translation errors that may not only distort the sentiment but at times flips the polarity of the source text to its exact opposite. In this thesis, we tackle the translation of sentiment in UGT by NMT systems from two perspectives: analytical and experimental. First, the analytical approach introduces a list of linguistic features that can lead to a mistranslation of ne-grained emotions between different language pairs in the UGT domain. It also presents an error-typology specifi c to Arabic UGT illustrating the main linguistic phenomena that can cause mistranslation of sentiment polarity when translating Arabic UGT into English by NMT systems. Second, the experimental approach attempts to improve the translation of sentiment by addressing some of the linguistic challenges identifi ed in the analysis as causing mistranslation of sentiment both on the word-level and on the sentence-level. On the word-level, we propose a Transformer NMT model trained on a sentiment-oriented vector space model (VSM) of UGT data that is capable of translating the correct sentiment polarity of challenging contronyms. On the sentence-level, we propose a semi-supervised approach to overcome the problem of translating sentiment expressed by dialectical language in UGT data. We take the translation of dialectical Arabic UGT into English as a case study. Our semi-supervised AR-EN NMT model shows improved performance over the online MT Twitter tool in translating dialectical Arabic UGT not only in terms of translation quality but also in the preservation of the sentiment polarity of the source text. The experimental section also presents an empirical method to quantify the notion of sentiment transfer by an MT system and, more concretely, to modify automatic metrics such that its MT ranking comes closer to a human judgement of a poor or good translation of sentiment

Biodiversité, biogéographie et évolution des hémosporidies dans l'océan Indien

Expliquer les patrons de biodiversité est l'un des objectifs majeurs de l'écologie. En dépit de l'accroissement de nos connaissances dans les domaines de la biologie évolutive et de l'écologie, la complexité et la multiplicité des processus impliqués dans l'assemblage des écosystèmes continuent de mettre les écologues à l'épreuve. La biogéographie s'est développée dans le but d'expliquer l'actuelle distribution des espèces en déterminant quels facteurs sont impliqués dans l'assemblage des communautés. Le travail présenté dans ce manuscrit a pour but de décrire et de comprendre quels processus ont été impliqués dans l'assemblage de communités de parasites insulaires. Nous nous sommes intéressés aux parasites sanguins de l'ordre Haemosporidia infectant les oiseaux de l'Océan Indien. Ce travail a permis d'augmenter nos connaissances sur les processus expliquant la diversité des parasites insulaires. Il est montré que les communautés hémosporidiennes de l'archipel des Mascareignes ont été assemblées par l'adjonction de multiples colonisations et de diversifications in-situ. Un groupe particulier de Leucocytozoon a colonisé l'Océan Indien en suivant ses hôtes Zosterops dans leur radiation évolutive. Une telle congruence des histoires biogéographiques des hôtes et des parasites n'a jamais été décrite chez les hémosporidies et a permis d'identifier plusieurs évènements de co-divergence et de proposer un taux d'évolution moléculaire pour les parasites. Nous décrivons également une diversité plus importante de Leucocytozoon dans les Mascareignes, comparé à Plasmodium. Ce patron peut être le produit de colonisations plus nombreuses ou plus anciennes des Leucocytozoon ou bien d'un plus faible turnover des lignées insulaires. Enfin, deux lignées de Leucocytozoon sont spatiallement ségrégées sur la Réunion et il est montré que ce patron ne peut être dû qu'à la seule influence des facteurs environnementaux. Nous suggérons que de la compétition ou des préférences pour différents vecteurs puissent être impliquées.Understanding biodiversity patterns is one of the major goals of ecology. Despite our increasing knowledge in the fields of evolutionary biology and ecology, the complexity and the multiplicicty of the processes underlying the assemblage of ecological systems continue to puzzle scientists. The field of biogeography has developed in an attempt to explain present species distributions by unravelling the factors involved in community assembly. The work presented in this manuscript aims at describing and understanding which processes were involved in the building of insular parasite communities. It specifically focuses on hemosporidian blood parasites infecting birds of the Indian Ocean and provides new insights into the processes explaining parasite diversity in insular systems. Results suggest that the hemosporidian communities of the Mascarene archipelago were assembled through a combination of multiple colonisations and in-situ diversifications. In particular, a group of Leucocytozoon parasites found their way to a number of islands in the Indian Ocean by following their Zosterops hosts in their evolutionary radiation. Such congruence of biogeographical histories of hosts and parasites has never been described in hemosporidians and allowed the identification of several co-divergence events, offering the possibility to date the parasite radiation and to propose a rate of molecular evolution for the parasites. Leucocytozoon parasites are also reported to be more diverse than Plasmodium in the Mascarene archipelago. This pattern may be the result of earlier and more numerous colonisations by Leucocytozoon. Alternatively, a lower turnover rate in Leucocytozoon could induce the same pattern. Finally, two lineages of Leucocytozoon are geographically segregated within the island of Réunion and we show that this pattern cannot be due to the sole effect of environmental factors and we suggest that competition or differential vector preference be involved

Saving Bones: a direct comparison of FTIR-ATR, whole bone percent nitrogen, and NIR

89th Annual Meeting of the American-Association-of-Physical-Anthropologists (AAPA), Los Angeles, CA, APR 15-18, 202