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Ensuring Access to Safe and Nutritious Food for All Through the Transformation of Food Systems
Maximum tolerable excess noise in CV-QKD and improved lower bound on two-way capacities
The two-way capacities of quantum channels determine the ultimate
entanglement distribution rates achievable by two distant parties that are
connected by a noisy transmission line, in absence of quantum repeaters. Since
repeaters will likely be expensive to build and maintain, a central open
problem of quantum communication is to understand what performances are
achievable without them. In this paper, we find a new lower bound on the
energy-constrained and unconstrained two-way quantum and secret-key capacities
of all phase-insensitive bosonic Gaussian channels, namely thermal attenuator,
thermal amplifier, and additive Gaussian noise, which are realistic models for
the noise affecting optical fibres or free-space links. Ours is the first
nonzero lower bound in the parameter range where the (reverse) coherent
information becomes negative, and it shows explicitly that entanglement
distribution is always possible when the channel is not entanglement breaking.
In addition, our construction is fully explicit, i.e. we devise and optimise a
concrete entanglement distribution and distillation protocol that works by
combining recurrence and hashing protocols.Comment: 41 pages, 11 figure
Metaphors of London fog, smoke and mist in Victorian and Edwardian Art and Literature
Julian Wolfreys has argued that after 1850 writers employed stock images of the city without allowing them to transform their texts. This thesis argues, on the contrary, that metaphorical uses of London fog were complex and subtle during the Victorian and Edwardian periods, at least until 1914. Fog represented, in particular, formlessness and the dissolution of boundaries. Examining the idea of fog in literature, verse, newspaper accounts and journal articles, as well as in the visual arts, as part of a common discourse about London and the state of its inhabitants, this thesis charts how the metaphorical appropriation of this idea changed over time. Four of Dickens's novels are used to track his use of fog as part of a discourse of the natural and unnatural in individual and society, identifying it with London in progressively more negative terms. Visual representations of fog by Constable, Turner, Whistler, Monet, Markino, O'Connor, Roberts and Wyllie and Coburn showed an increasing readiness to engage with this discourse. Social tensions in the city in the 1880s were articulated in art as well as in fiction. Authors like Hay and Barr showed the destruction of London by its fog because of its inhabitants' supposed degeneracy. As the social threat receded, apocalyptic scenarios gave way to a more optimistic view in the work of Owen and others. Henry James used fog as a metaphorical representation of the boundaries of gendered behaviour in public, and the problems faced by women who crossed them. The dissertation also examines fog and individual transgression, in novels and short stories by Lowndes, Stevenson, Conan Doyle and Joseph Conrad. After 1914, fog was no more than a crude signifier of Victorian London in literature, film and, later, television, deployed as a cliche instead of the subtle metaphorical idea discussed in this thesis
Queer spies in British Cold War culture: literature, film, theatre and television
This PhD thesis investigates how male homosexuality has been represented in British spy
fiction from the 1950s to the 2010s in multiple media: literature, film, television and
theatre. Due mainly to the betrayal of the Cambridge Spy ring around the middle of the
century, British culture has associated spies with homosexuality, while the wider
Anglophone world was in the grip of a homophobic atmosphere created by McCarthy's
Red Scare. My thesis explores how this history is reflected in the spy genre from the Cold
War to the present, in which male homosexuality and secret agency intersect as âqueerâ,
in so far as they were both considered to be discreet and criminal, existing outside of the
heteronormative order. By following multiple texts across media and time, I discuss how
some writers, television and film directors and actors update queer identity in spy fiction,
creating a shifting image of queer spies through decades. I refer to the findings of
adaptation studies and queer studies, along with numerous studies on spy fiction.
I conclude that the interrelation of different media has contributed to the re-drawing of queer identity in spy fiction. These developments have enabled the spies'
queer identity to transcend its pejorative history in British culture, towards its more
flexible and pliant sense which is designated by the term's modern usage. I also discuss
that spiesâ homosexuality has been represented as a fleeting ghost in most of the texts
examined, hovering on the margins of pages and screen. Although homosexuality is not
âthe love that dare not speak its nameâ anymore, clandestine queer spies have been
preserved as spectral others in the genre for many years. Spy fiction is a cultural
repository retaining the memory of violence inflicted against those who have been called
âqueerâ in twentieth century Britain, and the spectral nature of queer spies narrates this
history reaching back to the Oscar Wilde trial in 1895, from which point British queer
identity as we know now developed.
This thesis benefits the study of spy fiction by filling a gap in the investigation of
homosexual representation. It also contributes to the field of gender studies of literature,
film, television, and theatre by illustrating queer history in a genre which has not received
a great deal of focus on its representation of homosexuality. Spy fiction occupies a
central position in British popular culture, and by exploring this genre in terms of
homosexuality, this research will identify the role which same-sex desire has historically
played in the British cultural imagination
'Exarcheia doesn't exist': Authenticity, Resistance and Archival Politics in Athens
My thesis investigates the ways people, materialities and urban spaces interact to form affective ecologies and produce historicity. It focuses on the neighbourhood of Exarcheia, Athensâ contested political topography par excellence, known for its production of radical politics of discontent and resistance to state oppression and eoliberal capitalism. Embracing Exarcheiaâs controversial status within Greek vernacular, media and state discourses, this thesis aims to unpick the neighbourhoodsâ socio-spatial assemblage imbued with affect and formed through the numerous (mis)understandings and (mis)interpretations rooted in its turbulent political history. Drawing on theory on urban spaces, affect, hauntology and archival politics, I argue for Exarcheia as an unwavering archival space composed of affective chronotopes â (in)tangible loci that defy space and temporality. I posit that the interwoven narratives and materialities emerging in my fieldwork are persistently â and perhaps obsessively â reiterating themselves and remaining imprinted on the neighbourhoodâs landscape as an incessant reminder of violent histories that the state often seeks to erase and forget. Through this analysis, I contribute to understandings of place as a primary ethnographic âobjectâ and the ways in which place forms complex interactions and relationships with social actors, shapes their subjectivities, retains and bestows their memories and senses of historicity
Foundations for programming and implementing effect handlers
First-class control operators provide programmers with an expressive and efficient
means for manipulating control through reification of the current control state as a first-class object, enabling programmers to implement their own computational effects and
control idioms as shareable libraries. Effect handlers provide a particularly structured
approach to programming with first-class control by naming control reifying operations
and separating from their handling.
This thesis is composed of three strands of work in which I develop operational
foundations for programming and implementing effect handlers as well as exploring
the expressive power of effect handlers.
The first strand develops a fine-grain call-by-value core calculus of a statically
typed programming language with a structural notion of effect types, as opposed to the
nominal notion of effect types that dominates the literature. With the structural approach,
effects need not be declared before use. The usual safety properties of statically typed
programming are retained by making crucial use of row polymorphism to build and
track effect signatures. The calculus features three forms of handlers: deep, shallow,
and parameterised. They each offer a different approach to manipulate the control state
of programs. Traditional deep handlers are defined by folds over computation trees,
and are the original con-struct proposed by Plotkin and Pretnar. Shallow handlers are
defined by case splits (rather than folds) over computation trees. Parameterised handlers
are deep handlers extended with a state value that is threaded through the folds over
computation trees. To demonstrate the usefulness of effects and handlers as a practical
programming abstraction I implement the essence of a small UNIX-style operating
system complete with multi-user environment, time-sharing, and file I/O.
The second strand studies continuation passing style (CPS) and abstract machine
semantics, which are foundational techniques that admit a unified basis for implementing deep, shallow, and parameterised effect handlers in the same environment. The
CPS translation is obtained through a series of refinements of a basic first-order CPS
translation for a fine-grain call-by-value language into an untyped language. Each refinement moves toward a more intensional representation of continuations eventually
arriving at the notion of generalised continuation, which admit simultaneous support for
deep, shallow, and parameterised handlers. The initial refinement adds support for deep
handlers by representing stacks of continuations and handlers as a curried sequence of
arguments. The image of the resulting translation is not properly tail-recursive, meaning some function application terms do not appear in tail position. To rectify this the
CPS translation is refined once more to obtain an uncurried representation of stacks
of continuations and handlers. Finally, the translation is made higher-order in order to
contract administrative redexes at translation time. The generalised continuation representation is used to construct an abstract machine that provide simultaneous support for
deep, shallow, and parameterised effect handlers. kinds of effect handlers.
The third strand explores the expressiveness of effect handlers. First, I show that
deep, shallow, and parameterised notions of handlers are interdefinable by way of typed
macro-expressiveness, which provides a syntactic notion of expressiveness that affirms
the existence of encodings between handlers, but it provides no information about the
computational content of the encodings. Second, using the semantic notion of expressiveness I show that for a class of programs a programming language with first-class
control (e.g. effect handlers) admits asymptotically faster implementations than possible in a language without first-class control
Photography and Aesthetics: a critical study on visual and textual narratives in the lifework of Sergio LarraĂn and its impact in 20th century Europe and Latin America
The main focus of this study is a theoretical exploration of critical approaches applicable to the work of the Chilean photographer Sergio LarraĂn (1931-2012). It presents analytical tools to contextualise and understand the importance and impact of his work in photographic studies and his portrayal of twentieth-century Latin American and European culture. It inspects in depth a large portion of his photo work, which is still only partially published and mostly reduced to his "active" period as a photojournalist, aside from the personal photographic exploration of his early and late career (C. Mena). This extended material creates a broader scope for understanding his photographs and him as a canonical photographer. This study analyses the photographer's trajectory as discourses of recollection of historical memory in time (Mauad) to trace LarraĂn's collective memory associated with his visual production. Such analysis helps decode his visual imagery and his projection and impact on the European and Latin American culture. This strategy helps solve a two fold problem: firstly, it generates an interpretive consistency to understand the Chilean's photographic practice; secondly, it explores the power of images as an aesthetic experience in the installation of nationalist ideologies and the creation of imaginaries (B. Anderson 163)
NgÄ Tuituinga o te PĆtae: Rangatahi perspectives of leadership within NgÄti Maniapoto
Research on youth leadership development is often saturated by adult perceptions and thus the literature often lacks youth voice and youth perspective on what integral areas are needed for successful youth leadership development. This research focuses on the rangatahi of NgÄti Maniapoto and their perspectives of leadership within the iwi to aid the gap in academic literature relating to youth perception of leadership development.
Maniapoto has an abundance of leadership examples from the plethora of tĆ«puna that have developed the iwi to the leaders of contemporary Maniapoto pushing the iwi forward. The purpose of this research is to delve into the perspectives of rangatahi Maniapoto that pertain to good leadership qualities, their perception of leadership, unique leadership styles within Maniapoto, rangatahi leadership skills and perspectives of youth development within the iwi. By interviewing rangatahi with strong connection to Maniapoto this information of their perspectives revealed four integral areas of rangatahi leadership development were collated into a model for dissemination and use within the iwi for youth development practices. This model is named NgÄ Tuituinga o te PĆtae and has four areas, education, collective, communication and vision. Education was identified by rangatahi as they found that learning Maniapoto reo and tikanga was integral for a Maniapoto leader, in addition they saw an opportunity to establish a wÄnanga to future proof our Maniapototanga. A collective approach to leadership was highlighted as the rangatahi perceive that Maniapoto leaders need to be well known in the community and have good relationships with iwi members to be successful. Rangatahi reported that communication was an important attribute for leaders to have, not just speech but communicating by doing was essential for a Maniapoto leader. Finally, rangatahi explained that leaders need to have a vision for the taiao and a vision for our people to be a successful leader, and be able to take the iwi to a place they have not been to before.
This study adds to the scarce literature on youth perceptions on youth leadership development and definitively answers the question on how rangatahi of Maniapoto perceive leadership and how rangatahi of Maniapoto would develop leadership within Te Nehenehenui. The key findings presented in this thesis indicate that rangatahi from Maniapoto engage and identify leadership in many ways, however they do agree that leadership development is necessary for Maniapoto to flourish in the future. Applying this model and research within the iwi will create new foundations for leadership to grow within Maniapoto, and fill the gap of leadership for the iwi that rangatahi have identified
JESUS AND THE VISIBILITY OF GOD: SIGHT AND BELIEF IN THE FOURTH GOSPEL
This thesis establishes the value of the physical incarnation of God for belief. It asserts that the theological nature of belief derives from a God who can make himself physically visible in the world. While scholars have often debated the relationship between the empirical senses and belief in John, few have queried the presuppositions about Godâs invisibility that inform their positions. In response, this thesis argues across six chapters that unless God becomes physically visible in Jesus, belief does not obtain. Chapter 1 shows that God himself is ultimately the cause, content, and consequence of the belief that John 20:30-31 describes as the purpose of the Gospel. It establishes the theological nature of belief and thus the fact that the Gospel endeavours to draw humanity close to God via faith in Jesus. The remaining five chapters argue that seeing God in Jesus is both possible and desirable. Chapter 2 re-evaluates the metaphysics of divine visibility in Early Judaism and in John and concludes that God can be physically visible in Jesusâs body. John does not regard divinity as invisible in itself; rather, he claims that seeing Jesus is seeing God. Two long chapters follow and substantiate the claims of Chapter 2. They point up the entwined nature of divine presence and material reality by arguing that Jesusâs body is a divine place. This fact â coupled with Johnâs depiction of Jesus as a man in divine places â stresses his divinity on earth even as it reveals his localized humanity. Chapter 5 argues that sight itself is the primary catalyst for belief in John. Although human hearts occlude proper vision, seeing remains key to human apprehension of God and belief in him. Chapter 6 draws the foregoing together by arguing that seeing Jesus is seeing God across the Johannine narratives, both despite and because of their deeply counterintuitive climax in the crucifixion
Walking with the Earth: Intercultural Perspectives on Ethics of Ecological Caring
It is commonly believed that considering nature different from us, human beings (qua rational, cultural, religious and social actors), is detrimental to our engagement for the preservation of nature. An obvious example is animal rights, a deep concern for all living beings, including non-human living creatures, which is understandable only if we approach nature, without fearing it, as something which should remain outside of our true home. âWalking with the earthâ aims at questioning any similar preconceptions in the wide sense, including allegoric-poetic contributions. We invited 14 authors from 4 continents to express all sorts of ways of saying why caring is so important, why togetherness, being-with each others, as a spiritual but also embodied ethics is important in a divided world
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