Enzymatic depolymerization of alginate by two novel thermostable alginate lyases from Rhodothermus marinus

Alginate (alginic acid) is a linear polysaccharide, wherein (1→4)-linked β-D-mannuronic acid and its C5 epimer, α-L-guluronic acid, are arranged in varying sequences. Alginate lyases catalyze the depolymerization of alginate, thereby cleaving the (1→4) glycosidic linkages between the monomers by a β-elimination mechanism, to yield unsaturated 4-deoxy-L-erythro-hex-4-enopyranosyluronic acid (Δ) at the non-reducing end of resulting oligosaccharides (α-L-erythro configuration) or, depending on the enzyme, the unsaturated monosaccharide itself. In solution, the released free unsaturated monomer product is further hydrated in a spontaneous (keto-enol tautomerization) process to form two cyclic stereoisomers. In this study, two alginate lyase genes, designated alyRm3 and alyRm4, from the marine thermophilic bacterium Rhodothermus marinus (strain MAT378), were cloned and expressed in Escherichia coli. The recombinant enzymes were characterized, and their substrate specificity and product structures determined. AlyRm3 (PL39) and AlyRm4 (PL17) are among the most thermophilic and thermostable alginate lyases described to date with temperature optimum of activity at ∼75 and 81°C, respectively. The pH optimum of activity of AlyRm3 is ∼5.5 and AlyRm4 at pH 6.5. Detailed NMR analysis of the incubation products demonstrated that AlyRm3 is an endolytic lyase, while AlyRm4 is an exolytic lyase, cleaving monomers from the non-reducing end of oligo/poly-alginates

An Optimal Algorithm for Sliding Window Order Statistics

Assume there is a data stream of elements and a window of size m. Sliding window algorithms compute various statistic functions over the last m elements of the data stream seen so far. The time complexity of a sliding window algorithm is measured as the time required to output an updated statistic function value every time a new element is read. For example, it is well known that computing the sliding window maximum/minimum has time complexity O(1) while computing the sliding window median has time complexity O(log m). In this paper we close the gap between these two cases by (1) presenting an algorithm for computing the sliding window k-th smallest element in O(log k) time and (2) prove that this time complexity is optimal

Multiparty Selection

Given a sequence A of n numbers and an integer (target) parameter 1 ? i ? n, the (exact) selection problem is that of finding the i-th smallest element in A. An element is said to be (i,j)-mediocre if it is neither among the top i nor among the bottom j elements of S. The approximate selection problem is that of finding an (i,j)-mediocre element for some given i,j; as such, this variant allows the algorithm to return any element in a prescribed range. In the first part, we revisit the selection problem in the two-party model introduced by Andrew Yao (1979) and then extend our study of exact selection to the multiparty model. In the second part, we deduce some communication complexity benefits that arise in approximate selection. In particular, we present a deterministic protocol for finding an approximate median among k players

Interviewee: The Harrisons; Interviewer: Snæbjörnsdóttir/Wilson

Bryndis Snæbjörnsdóttir and Mark Wilson conduct their collaborative practice from bases in the north of England and Reykjavík, Iceland. With a strong research grounding, their socially engaged projects explore contemporary relationships between human and non-human animals in the contexts of history, culture and the environment. This exclusive interview with leading pioneer of eco-art Newton (and Helen Mayer) Harrison, concerns the Harrisons' lives' work, the launch of their major monograph The Time of the Force Majeure, and urgent issues of ecocriticism and the arts. Text and questions by Snæbjörnsdóttir /Wilson

On the Receiving End: The Role of Scholarship, Memory, and Genre in Constructing Ljósvetninga saga

This thesis reveals how scholarly preconceptions guided the reception of a specific saga, Ljósvetninga saga, and contributes to a wider understanding of how saga, Old Norse, medieval, and general literature are each constantly changing and unstable, both in their preservation, and in the ways they are presented to the general public and scholarly community. It focuses on issues of memory and genre that arise from a material philology approach, providing a literary analysis of both redactions of the saga as independent texts with their own intrinsic value.Ljósvetninga saga takes place in Northern Iceland during the tenth and eleventh centuries and focuses on the political maneuverings of the chieftain Guðmundr inn ríki Eyjólfsson and his son Eyjólfr. Most of the academic debate surrounding Ljósvetninga saga has focused on the issue of its origins. This saga, most likely written in the thirteenth century, is atypical in that it has two seperate redactions that offer highly divergent information and narratives in several segments, dividing the saga between the A-redaction, based on the late fourteenth–early fifteenth-century manuscript AM 561 4to, and the C-redaction, based on the mid-fifteenth-century manuscript AM 162 c fol. and its approximately fifty post-medieval paper copies. The divergent redactions are the source of much speculation about the text’s origins, split between an interpretation of oral composition, commonly referred to as Freeprose, and one of written composition, commonly referred to as Bookprose. These two understandings of the saga are also tied to two different editions of the saga, which have been alternately used to elevate one redaction over the other. Theodore Andersson’s attempt to shift the debate toward a compromise between Freeprose and Bookprose has only been partially successful, due, among other reasons, to his continued elevation of one redaction (the C-redaction). This thesis approaches both redactions as independent, internally-coherent texts rather than stressing their literary relationship. The thesis deals with its primary question: How did the reception of Ljósvetninga saga influence its construction? It shows that Ljósvetninga saga has been constantly rewritten over time by its oral performers, its literary authors, its scribes, its publishers, and its scholars. In the introduction, the thesis establishes its material philology approach, presents its assumptions about medieval authorship and intentionality, and argues for the use of the paper manuscript AM 485 4to as the base manuscript for its treatment of C-redaction. The scholarly debate about the saga is presented with special attention paid to matters of origins and dating, examining Ljósvetninga saga’s relationship with Brennu-Njáls saga, and what is gained from a literary connection between the two. A literary interpretation of both redactions as texts that have their own intrinsic value is provided, showing how each of these texts creates meaning using internal connections, including the C-redaction’s þættir. Ljósvetninga saga is used as a tool to discuss the role of cultural memory in composition and interpretation, with a stress on the scholar Barði Guðmundsson, AM 162 c fol.’s fifteenth-century scribe Ólafur Loftsson, and AM 561 4to’s hypothetical fourteenth-century context. The thesis offers a synchronic and a diachronic reading: the first treats memory as a template for events and people contemporaneous with the author, whereas the second acknowledges both past and present as significant for interpretation. The thesis also examines Ljósvetninga saga in its generic context, questioning and expanding the definition of the Íslendingasögur (Sagas of Early Icelanders) category, and rejecting the usefulness of the term ‘post-classical’ Íslendingasögur altogether. Using Rick Altman’s concept of generic crossroads, the thesis analyses both redactions’ manuscripts’ approach to the issue of power. This thesis reveals how scholarly preconceptions guided the reception of a specific saga, Ljósvetninga saga, and contributes to a wider understanding of how saga, Old Norse, medieval, and general literature are each constantly changing and unstable, both in their preservation, and in the ways they are presented to the general public and scholarly community.Ljósvetninga saga gerist á Norðurlandi á tíundu og elleftu öld og fjallar fyrst og fremst um pólitískar fléttur höfðingjans Guðmundar hins ríka Eyjólfssonar og sonar hans Eyjólfs. Fræðileg umræða um Ljósvetninga sögu hefur öðru fremur einblínt á uppruna hennar. Sagan, sem talin er rituð á þrettándu öld, er óvenjuleg að því leyti að hún er varðveitt í tveim gerðum sem mjög eru frábrugðnar um ýmis atriði og atburði. Þannig skiptist sagan í A-gerð, sem byggð er á handritinu AM 561 4to frá seinni hluta fjórtándu aldar eða upphafi þeirrar fimmtándu, og í C-gerð, sem byggð er á handritinu AM 162 c fol. frá miðri fimmtándu öld og um það bil fimmtíu pappírsafritum sem rituð eru eftir siðbreytingu. Hinar frábrugðnu gerðir sögunnar hafa orðið tilefni til mikilla vangaveltna um uppruna sögunnar og skiptar skoðanir þar um. Ein skoðun er sú að sagan sé upprunnin í munnlegri geymd og er kennd við skóla sagnfestukenningarinnar, en önnur skoðun er sú að sagan sé frumsamin á bókfell og er hún kennd við bókfestukenninguna. Sá ólíki skilningur sem lagður er í söguna út frá þessum tveim meginkenningum tengjast sömuleiðis tveim ólíkum fræðilegum útgáfum á sögunni, sem hvor um sig hafa verið notaðar sem rök fyrir gildi annarrar gerðarinnar fram yfir hina. Tilraun Theodore Andersson til að sætta umræðuna og fara bil beggja kenninga hefur ekki tekist nema að hluta til, meðal annars vegna þeirrar óbilandi afstöðu sem hann tekur með C-gerð sögunnar. Í þessari ritgerð verður litið svo á að báðar gerðir sögunnar séu sjálfstæðir og sjálfum sér samkvæmir textar fremur en að bókmenntaleg tengsl þeirra verði í forgrunni. Lykilspurningin sem ritgerðinni er ætlað að svara er: Hvaða áhrif höfðu viðtökur Ljósvetninga sögu áhrif á samsetningu hennar? Hér verður sýnt að Ljósvetninga saga hefur stöðugt verið endursamin hvort heldur sem er í munnlegum flutningi, af bóklegum höfundum hennar, handritaskrifurum, útgefendum og fræðimönnum. Aðferðir efnislegrar textafræði eru grundvöllur rannsóknarinnar. Í inngangi eru kynntar forsendur rannsóknarinnar er varða höfunda á miðöldum og bókmenntalegan atbeina þeirra, og rök eru færð fyrir því að pappírshandritið AM 485 4to sé grundvallarhandrit að C-gerðinni. Áhersla verður lögð á þá fræðilegu umræðu um söguna sem hefur að gera með uppruna hennar og aldur. Þar með verða tengsl Ljósvetninga sögu við Brennu-Njáls sögu skoðuð og hvað samband þessara texta getur sagt okkur. Báðar gerðir sögunnar eru greindar með aðferðum bókmenntafræði enda eru þær sjálfstæðar gerðir sem hvor hefur gildi í sjálfri sér, og það er sýnt hvernig merkingarsköpun hvors texta hangir saman við innbyrðis tengingar, þar með talið þætti C-gerðarinnar. Ljósvetninga saga er ennfremur notuð sem rammi um umræðu um hlutverk menningarminnis í samsetningu og túlkun sögunnar, með áherslu á fræðileg skrif Barða Guðmundssonar, skrifara fimmtándu aldar handritsins AM 162 c fol., og ætlað fjórtándu aldar samhengi handritsins AM 561 4to. Ritgerðin býður hvort tveggja upp á samtímalegan og sögulegan lestur á sögunni; hinn fyrri lítur á minni sem skapalón fyrir notkun atburða og persóna samtíða höfundinum, meðan hinn síðari viðurkennir að hvort tveggja fortíð og nútíð skipta máli fyrir túlkun texta. Ritgerðin kannar einnig bókmenntagrein Ljósvetninga sögu og færir fram efasemdir um og útvíkkun á skilgreiningu Íslendingasagna, og hafnar jafnframt alfarið hugtakinu ‘unglegar’ eða ‘póstklassískar’ Íslendingasögur. Með stuðningi í hugtaki Rick Altman ‘vegamót bókmenntagreina’ (e. generic crossroads) er ráðist í greiningu á nálgun handrita beggja gerða sögunnar á völd. Ritgerðin leiðir í ljós hvernig fyrirframgefnar ályktanir fræðimanna hafa haft áhrif á viðtökur Ljósvetninga sögu. Hún er framlag til aukins skilnings á því hvernig forníslenskar sögur og bókmenntir almennt eru stöðugt breytingum háðar, bæði hvað geymd þeirra snertir og hvernig þær eru kynntar almenningi og fræðasamfélaginu.163292-05

THE JAMAICA CONSTABULARY FORCE: TRANSFORMATION TO MEET THE CHALLENGES OF THE 21ST CENTURY

If there is one single expectation of Government, which we share throughout our lives, it is security and protection. This is one of the most basic functions of all forms of Government throughout the ages. This policy paper, inevitably concentrates on those aspects of reform, which are primarily matters for the police. However, we approach radical change not from the standpoint of those delivering the service, but from those reliant on it. We want to look at the way in which we can substantially improve the standard, reliability, consistency, and responsiveness of the service. Jamaicans of all ages are sick and tired of anti-social thuggish behaviour. They are fed up with hearing that ‘nothing can be done’ or ‘if only’ someone else would do something, then ‘we might be able to help’. Our task is clear. We want to prevent, detect, apprehend, and convict the perpetrators of crime. We need and should have a process that enables those undertaking the basic task of protecting our homes, our streets, and our persons, to do the job more effectively. Whether in dramatically slimming down bureaucracy and reassigning tasks in a way that frees up police officers to do their real job more effectively, or in extending what we are calling the ‘police family’ to engage others in policing, or in adopting more modern techniques: Change must be brought about. But the challenge of modernisation is to bring about the kind of improvements that are welcomed by everyone – except those more concerned about protecting their comfortable ways of working. The challenge to us is to provide the means which will enable police officers and support staff to work better, and to do their job free from complicated and time consuming procedures, unnecessary to achieve results or to protect basic rights. For it is those who are least able to buy their way out of deprived and drug-ridden neighbourhoods, who cannot afford private protection or security checks, who are the main victims of crime. So, for those who care most about human rights, it is the elderly and frail, the intimidated mother with children threatened by drug pushers, and those without a car to visit friends , which should provide the motivation for action and support. In the end, it will not be the statistics on crime falling, or targets met, but rather the difference felt in the neighbourhood and community itself which will be judge and jury of these reforms. It is time to focus on preventing crime and protecting the victims, and to place the weight of society behind this drive to reform the police.Jamaica,JCF,Jamaica Constabulary Force,Jamaica Police reform, Police Reform

Representations of Christ in Christian Skaldic Poetry

This thesis aims to demonstrate that, through use of literary genre, vocabulary, and emphasis of detail, the authors of Christian skaldic verse in the twelfth to fifteenth centuries continually reshaped a specific set of representations for Christ to suit each poem’s individual purpose, its audience, and the literary tastes of the periods in which they were written. In order to show how Christ’s portrayal changes over time and according to each poem’s overarching purpose, I have selected the following five Christian skaldic poems and made each the focus of a chapter: Einarr Skúlason’s Geisli, Gamli kanóki’s Harmsól, and the anonymously-composed poems Leiðarvísan, Líknarbraut, and Lilja. Within each chapter I provide an overview of the poem, selecting stanzas that highlight features of Christ that are prevalent or striking in some way, and analyse how these representations not only influence the poem itself, but also shape perceptions of Christ’s relationship with humanity. Each chapter leads to an overall consideration both of the image of Christ as this has been represented, and of the degree to which this has been influenced by biblical and patristic writings, Old Norse literature and culture, or by a combination of these elements. In the concluding chapter I identify the prevailing representations of Christ throughout these five poems, dividing these characterisations into five categories: Christ as Warrior Chieftain, as Healer and Abundant Nourisher, as Legal Authority, as Beguiler, and as Light. I assess the changing importance of each of these representations over time and in these poems, in order to enable a better understanding of the changing images of Christ in the medieval skaldic corpus and how these may reflect locally specific perceptions of Christ

Tam o' Shanter: A Nordic Tinge

Tam o’ Shanter, a great narrative poem written by Roberts Burns, is written in Scots and as such is difficult to access by standard English speakers and non-natives alike. This monograph offers an account of the language of Tam as characterised by a significant number of distinctive lexical and phonological items related to Old Norse. It is claimed that Old Norse constitutes an essential and highly descriptive element of the poem in terms of dramatic impact, soundscape, timing, and pace. As the beating heart of Tam, this element is identified and described as constituting the core of the poem’s linguistic fusion, and it is related to present-day Icelandic and Swedish. A new translation of the poem is also proposed in order to increase accessibility to a wider audience