537 research outputs found
Stone-Type Dualities for Separation Logics
Stone-type duality theorems, which relate algebraic and
relational/topological models, are important tools in logic because -- in
addition to elegant abstraction -- they strengthen soundness and completeness
to a categorical equivalence, yielding a framework through which both algebraic
and topological methods can be brought to bear on a logic. We give a systematic
treatment of Stone-type duality for the structures that interpret bunched
logics, starting with the weakest systems, recovering the familiar BI and
Boolean BI (BBI), and extending to both classical and intuitionistic Separation
Logic. We demonstrate the uniformity and modularity of this analysis by
additionally capturing the bunched logics obtained by extending BI and BBI with
modalities and multiplicative connectives corresponding to disjunction,
negation and falsum. This includes the logic of separating modalities (LSM), De
Morgan BI (DMBI), Classical BI (CBI), and the sub-classical family of logics
extending Bi-intuitionistic (B)BI (Bi(B)BI). We additionally obtain as
corollaries soundness and completeness theorems for the specific Kripke-style
models of these logics as presented in the literature: for DMBI, the
sub-classical logics extending BiBI and a new bunched logic, Concurrent Kleene
BI (connecting our work to Concurrent Separation Logic), this is the first time
soundness and completeness theorems have been proved. We thus obtain a
comprehensive semantic account of the multiplicative variants of all standard
propositional connectives in the bunched logic setting. This approach
synthesises a variety of techniques from modal, substructural and categorical
logic and contextualizes the "resource semantics" interpretation underpinning
Separation Logic amongst them
The 2007 Provincial Election and Electoral System Referendum in Ontario
Ontarioâs general election in Oct. 10, 2007, was unprecedented for several reasons. The election was held on a date fixed by legislation and not one set by the premier or his caucus, something new to Ontario and relatively new to Canadian politics. Turnout declined to 53%, the lowest ever in Ontario history. The incumbent Liberals won a second consecutive majority government, something the party had not achieved since 1937. And finally, the election featured a referendum question that asked voters in Ontario to approve reforms to the electoral system, a proposal that was overwhelmingly rejected. This article explores each of the above-stated elements as they unfolded in the election
Exit Polling in Canada: An Experiment
Although exit polling has not been used to study Canadian elections before, such polls have methodological features that make them a potentially useful complement to data collected through more conventional designs. This paper reports on an experiment with exit polling in one constituency in the 2003 Ontario provincial election. Using student volunteers, a research team at Wilfrid Laurier University conducted an exit poll in the bellwether constituency of Kitchener Centre to assess the feasibility of mounting this kind of study on a broader scale. The experiment was successful in a number of respects. It produced a sample of 653 voters that broadly reflected the partisan character of the constituency, and which can hence be used to shed light on patterns of vote-switching and voter motivations in that constituency. It also yielded insights about best practices in mounting an exit poll in the Ontario context, as well as about the potential for using wireless communication devices to transmit respondent data from the field. The researchers conclude that exit polling on a limited basis (selected constituencies) is feasible, but the costs and logistics associated with this methodology make a province-wide or country-wide study unsupportable at present
Provability in BI's Sequent Calculus is Decidable
The logic of Bunched Implications (BI) combines both additive and
multiplicative connectives, which include two primitive intuitionistic
implications. As a consequence, contexts in the sequent presentation are not
lists, nor multisets, but rather tree-like structures called bunches. This
additional complexity notwithstanding, the logic has a well-behaved metatheory
admitting all the familiar forms of semantics and proof systems. However, the
presentation of an effective proof-search procedure has been elusive since the
logic's debut. We show that one can reduce the proof-search space for any given
sequent to a primitive recursive set, the argument generalizing Gentzen's
decidability argument for classical propositional logic and combining key
features of Dyckhoff's contraction-elimination argument for intuitionistic
logic. An effective proof-search procedure, and hence decidability of
provability, follows as a corollary.Comment: Submitted to CADE-2
Development networks and urban growth in small cities
Real estate development is an intensely social process dependent on rich networks of relations between public and private sector actors. Previous work has explored how far such relations are formalised in large cities through shared coalitions of interest intended to promote urban growth. Relatively little attention has been given to networks in smaller cities, which is the concern of this paper. Drawing on detailed research in a small Scottish city, the paper explores how its local network was characterised by strong reliance on network construction and reproduction through trust and reputation. Significantly, within such local networks, competition and collaboration can exist side by side, without subsuming normal tensions into consistent agendas or formally defined âpartnershipsâ. Controlling land for urban expansion provides a particular focus for these tensions, since it can allow certain interests to gain network dominance. These findings raise important concerns around whether small cities should rely on informal networks to promote growth instead of constructing formal coalitions that may attract more externally based actors. Such choices have profound implications for the capacity and transparency of development networks, and thus for the accountability of the urban development process
Simple and objective prediction of survival in patients with lung cancer: staging the host systemic inflammatory response
Background. Prediction of survival in patients diagnosed with lung cancer remains problematical. The aim of the present study was to examine the clinical utility of an established objective marker of the systemic inflammatory response, the Glasgow Prognostic Score, as the basis of risk stratification in patients with lung cancer. Methods. Between 2005 and 2008 all newly diagnosed lung cancer patients coming through the multidisciplinary meetings (MDTs) of four Scottish centres were included in the study. The details of 882 patients with a confirmed new diagnosis of any subtype or stage of lung cancer were collected prospectively. Results. The median survival was 5.6 months (IQR 4.8â6.5). Survival analysis was undertaken in three separate groups based on mGPS score. In the mGPS 0 group the most highly predictive factors were performance status, weight loss, stage of NSCLC, and palliative treatment offered. In the mGPS 1 group performance status, stage of NSCLC, and radical treatment offered were significant. In the mGPS 2 group only performance status and weight loss were statistically significant. Discussion. This present study confirms previous work supporting the use of mGPS in predicting cancer survival; however, it goes further by showing how it might be used to provide more objective risk stratification in patients diagnosed with lung cancer
The Role of Ageing and Parenchymal Senescence on Macrophage Function and Fibrosis
In this review, we examine senescent cells and the overlap between the direct biological impact of senescence and the indirect impact senescence has via its effects on other cell types, particularly the macrophage. The canonical roles of macrophages in cell clearance and in other physiological functions are discussed with reference to their functions in diseases of the kidney and other organs. We also explore the translational potential of different approaches based around the macrophage in future interventions to target senescent cells, with the goal of preventing or reversing pathologies driven or contributed to in part by senescent cell load in vivo
Delivering lower carbon urban transport choices: European ambition meets the reality of institutional (mis)alignment.
Reducing carbon emissions from the transport sector has become a critical imperative for public policy as our understanding of the impacts of the mobility system on the environment has developed. This paper contrasts policy development in three cities (Aberdeen, Bremen and Malmö) that collaborated as part of a European Union knowledge exchange programme designed to share innovative approaches to carbon reduction in the transport sector. We identify a number of critical aspects of governance, including the approach to policy formulation and implementation, and the status of consensus and cohesion, as key determinants of transport outcomes. We conclude that the degree of institutional alignment evident in each cityâs governance network is crucial in explaining their appetite for the pursuit of low carbon policies, and in turn the real potential for policy transfer to occur as envisaged by European Union collaboration frameworks
Collective futures: cultivating creative collectives.
Collective Futures was a partnership project between three highly regarded institutions operating in the creative industries: Gray's School of Art, University of The West of Scotland (UWS) and the Glasgow School of Art. The partners undertook a unique exploration of creative collectives as a route to economic success and talent development for designer-makers. The collaborative nature of the partnership working throughout the project was recognised by the partners as a form of Creative Academic Collective. The aims of the project were consistent with Creative Scotland's strategic intention to support talent hubs for creative practitioners, and also aligned with recent reports (EKOS) and initiatives such as the South of Scotland Social Enterprise Initiative (SOSCEI), Creative Arts Business Network (CABN) and Emergents, that reinforced the importance of scale, networking, collaboration and the notion of creative places around the country to support creative industries. Central to the success of the project was a meaningful connection and engagement of designer/maker communities and creative practitioners in several parts of Scotland. This project sought to explore effective models of collective working that support designer/makers in the development of their own talent and to sustain and grow their creative businesses
Arctic river temperature dynamics in a changing climate
Climate change in the Arctic is expected to have a major impact on stream ecosystems, affecting hydrological and thermal regimes. Although temperature is important to a range of inâstream processes, previous Arctic stream temperature research is limitedâfocused on glacierised headwaters in summerâwith limited attention to snowmelt streams and winter. This is the first highâresolution study on stream temperature in northâeast Greenland (Zackenberg). Data were collected from five streams from September 2013 to September 2015 (24 months). During the winter, streams were largely frozen solid and water temperature variability low. Spring iceâoff date occurred simultaneously across all streams, but 11 days earlier in 2014 compared with 2015 due to thicker snow insulation. During summer, water temperature was highly variable and exhibited a strong relationship with meteorological variables, particularly incoming shortwave radiation and air temperature. Mean summer water temperature in these snowmelt streams was high compared with streams studied previously in Svalbard, yet was lower in Swedish Lapland, as was expected given latitude. With global warning, Arctic stream thermal variability may be less in summer and increased during the winter due to higher summer air temperature and elevated winter precipitation, and the spring and autumn iceâon and iceâoff dates may extend the flowing water seasonâin turn affecting stream productivity and diversity
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