Jörg Ritter

In almost all current approaches, the collation of large texts is applied to a fixed given segmentation of the two texts witnesses to be compared and consists of two consecutive steps. First, the segments of the two texts are aligned, and then the aligned segments are compared in detail. For larger manuscripts or books consisting of many pages, the segments are usually the paragraphs of the texts. When comparing two texts, where the second text is a revised version of the first, poor local alignments can arise. This occurs in places where paragraphs have been split into two smaller paragraphs to insert a new paragraph in between, or where several consecutive sentences have been moved from one paragraph to the previous or next paragraph. Most paragraph collation tools cannot handle these scenarios properly because they align each paragraph with at most one paragraph of the other text. In this paper, we discuss this problem in detail and present a heuristic for resegmenting the two texts to be compared in order to achieve a better collation.

In this paper,(0) we present a method for paraphrase extraction in Ancient Greek that can be applied to huge text corpora in interactive humanities applications. Since lexical databases and POS tagging are either unavailable or do not achieve sufficient accuracy for ancient languages, our approach is based on pure word embeddings and the word mover's distance (WMD) [20]. We show how to adapt the WMD approach to paraphrase searching such that the expensive WMD computation has to be computed for a small fraction of the text segments contained in the corpus, only. Formally, the time complexity will be reduced from O (N . K-3 . log K) to O(N + K-3 - log K), compared to the brute-force approach which computes the WMD between each text segment of the corpus and the search query. N is the length of the corpus and K the size of its vocabulary. The method, which searches not only for paraphrases of the same length as the search query but also for paraphrases of varying lengths, was evaluated on the Thesaurus Linguae Graecae (R) (TLG (R)) [25]. The TLG consists of about 75 - 10(6) Greek words. We searched the whole TLG for paraphrases for given passages of Plato. The experimental results show that our method and the brute-force approach, with only very few exceptions, propose the same text passages in the TLG as possible paraphrases. The computation times of our method are in a range that allows its application in interactive systems and let the humanities scholars work productively and smoothly.

Activity of the renin-angiotensin-aldosterone system is thought to play a major role in determining blood pressure (BP) and target organ damage such as left ventricular hypertrophy. In Afro-Caribbean subjects, however, hypertension tends to be more severe despite lower plasma renin activity. We investigated whether this might be due to a different relation between aldosterone and renin in Afro-Caribbean compared to white subjects. Plasma aldosterone and renin activity were assessed in the morning after 15 min seated in 383 hypertensive subjects of Afro-Caribbean or white ethnicity (61% Afro-Caribbean, 83% on treatment) attending a hypertension clinic in London, UK. Left ventricular mass index (LVMI) was assessed by echocardiography in 276 subjects. Plasma renin activity was lower in Afro-Caribbean compared to white subjects (0.4 [0.3-1.0] v 1.4 [0.5-3.4] ng/mL/h, medians [interquartile range], P < .0001). Despite this, aldosterone was higher in Afro-Caribbean compared to white subjects (8.0 [6.1-12.6] v 7.4 [2.3-17.1] ng/dL, medians [interquartile range], P < .01). The LVMI corrected for sex and BP was higher in Afro-Caribbean than in white subjects. In Afro-Caribbean but not in white subjects LVMI was independently correlated with plasma aldosterone (standardized regression coefficient, beta= 0.25, P < .001). In Afro-Caribbean hypertensive subjects in London, plasma aldosterone is elevated despite lower renin and may contribute to increased severity of hypertension and left ventricular hypertrophy in Afro-Caribbean compared to white subjects.