316 research outputs found
From Display to Labelled Proofs for Tense Logics
We introduce an effective translation from proofs in the display calculus to proofs in the labelled calculus in the context of tense logics. We identify the labelled calculus proofs in the image of this translation as those built from labelled sequents whose underlying directed graph possesses certain properties. For the basic normal tense logic Kt, the image is shown to be the set of all proofs in the labelled calculus G3Kt
A Focused Sequent Calculus Framework for Proof Search in Pure Type Systems
Basic proof-search tactics in logic and type theory can be seen as the
root-first applications of rules in an appropriate sequent calculus, preferably
without the redundancies generated by permutation of rules. This paper
addresses the issues of defining such sequent calculi for Pure Type Systems
(PTS, which were originally presented in natural deduction style) and then
organizing their rules for effective proof-search. We introduce the idea of
Pure Type Sequent Calculus with meta-variables (PTSCalpha), by enriching the
syntax of a permutation-free sequent calculus for propositional logic due to
Herbelin, which is strongly related to natural deduction and already well
adapted to proof-search. The operational semantics is adapted from Herbelin's
and is defined by a system of local rewrite rules as in cut-elimination, using
explicit substitutions. We prove confluence for this system. Restricting our
attention to PTSC, a type system for the ground terms of this system, we obtain
the Subject Reduction property and show that each PTSC is logically equivalent
to its corresponding PTS, and the former is strongly normalising iff the latter
is. We show how to make the logical rules of PTSC into a syntax-directed system
PS for proof-search, by incorporating the conversion rules as in
syntax-directed presentations of the PTS rules for type-checking. Finally, we
consider how to use the explicitly scoped meta-variables of PTSCalpha to
represent partial proof-terms, and use them to analyse interactive proof
construction. This sets up a framework PE in which we are able to study
proof-search strategies, type inhabitant enumeration and (higher-order)
unification
Cisplatin-induced ototoxicity: the current state of ototoxicity monitoring in New Zealand.
Background: Many well-known pharmacologic agents have been shown to have toxic effects to the cochleo-vestibular system. Examples of such ototoxic agents include cisplatin and aminoglycoside antibiotics. Ototoxicity monitoring consists of a comprehensive pattern of audiological assessments designed to detect the onset of any hearing loss. Three main methods have emerged over the past decade, and include the basic audiological assessment, extended high frequency (EHF) audiometry, and otoacoustic emission (OAE) measurement. These measures can be used separately or in combination, depending on clinical purpose and patient considerations. It is suggested by the American Academy of Audiology Position Statement and Clinical Practice Guidelines: Ototoxicity Monitoring, that baseline testing be done in a fairly comprehensive manner, including pure-tone thresholds in both the conventional- and extended high frequency ranges, tympanometry, speech audiometry, and the testing of OAEs (AAA, 2009). Anecdotal evidence suggests that New Zealand Audiologists do not currently follow a national ototoxicity monitoring protocol. Therefore the main aim of this study was to explore the current status of ototoxicity monitoring within New Zealand.
Hypothesis: It was hypothesized that hospital based Audiology departments across New Zealand each followed their own internal ototoxicity monitoring protocol based, to a large extent, on the guidelines proposed by the American Academy of Audiology and by the American Speech-Language-Hearing Association.
Method: Through the use of a Telephone Interview Questionnaire, 16 charge Audiologists were interviewed to establish their current state of knowledge regarding ototoxicity monitoring at 16 out of 20 district health boards in New Zealand. Enquiries about the current systems and procedures in place at their departments together with any suggestions and recommendations to improve on these systems were made.
Results: This study found that only 9 of the 16 DHBs interviewed currently follow an ototoxicity monitoring protocol. Furthermore, other than initially hypothesized the origin of the protocols followed by the remaining 7 departments were reported to have ranged from independently developed protocols to historically adopted protocols. One department implemented an adapted version of a protocol by Fausti et al. (Ear and Hearing 1999; 20(6):497-505). This diversity in origin however, does confirm our initial suspicion that no universal and standardized monitoring protocol is currently being followed by Audiologists working in the public health sector of New Zealand
Refocusing generalised normalisation
When defined with general elimination/application rules, natural
deduction and -calculus become closer to sequent
calculus. In order to get real isomorphism, normalisation has to
be defined in a ``multiary'' variant, in which reduction rules are
necessarily non-local (reason: nomalisation, like cut-elimination,
acts at the \emph{head} of applicative terms, but natural
deduction focuses at the \emph{tail} of such terms). Non-local
rules are bad, for instance, for the mechanization of the system.
A solution is to extend natural deduction even further to a
\emph{unified calculus} based on the unification of cut and
general elimination. In the unified calculus, a sequent term
behaves like in the sequent calculus, whereas the reduction steps
of a natural deduction term are interleaved with explicit steps
for bringing heads to focus. A variant of the calculus has the
symmetric role of improving sequent calculus in dealing with
tail-active permutative conversions
Bun splitting: a practical cutting stock problem
We describe a new hierarchical 2D-guillotine Cutting Stock Problem. In contrast to the classic cutting stock problem, waste is not an issue. The problem relates to the removal of a defective part and assembly of the remaining parts into homogeneous size blocks. The context is the packing stages of cake manufacturing. The company's primary objective is to minimise total processing time at the subsequent, packing stage. This objective reduces to one of minimising the number of parts produced when cutting the tray load of buns. We offer a closed form optimization approach to this class of problems for certain cases, without recourse to mathematical programming or heuristics. The methodology is demonstrated through a case study in which the number of parts is reduced by almost a fifth, and the manufacturer's subsidiary requirement to reduce isolated single bun parts and hence customer complaints is also satisfied
Inhibition of DAMP signaling as an effective adjunctive treatment strategy in pneumococcal meningitis
Background: Pneumococcal meningitis remains a potentially lethal and debilitating disease, mainly due to brain damage from sustained inflammation. The release of danger-associated molecular patterns (DAMPs), like myeloid-related protein 14 (MRP14) and high mobility group box 1 protein (HMGB1), plays a major role in persistence of inflammation. In this study, we evaluated if paquinimod, an MRP14-inhibitor, and an anti-HMGB1 antibody can improve clinical outcome as adjunctive therapeutics in pneumococcal meningitis. Methods: We tested the adjuvant administration of paquinimod and the anti-HMGB1 antibody in our pneumococcal meningitis mouse model assessing clinical (clinical score, open-field-test, temperature) and pathophysiological parameters (intracranial pressure, white blood cell count in CSF, bleeding area) as well as bacterial titers in blood and brain 24 h after administration and 48 h after infection. Furthermore, we explored the interactions of these two agents with dexamethasone, the standard adjuvant treatment in pneumococcal meningitis (PM), and daptomycin, a nonbacteriolytic antibiotic preventing pathogen-associated molecular pattern (PAMP) release. Results: Adjunctive inhibition of MRP14 or HMGB1 reduced mortality in mice with PM. This effect was lost when the two anti-DAMP agents were given simultaneously, possibly due to excessive immunosuppression. Combining anti-PAMP (daptomycin) and anti-DAMP treatments did not produce synergistic results;instead, the anti-DAMP treatment alone was sufficient and superior. The combination of anti-HMGB1 with dexamethasone did not diminish the effect of the former. Conclusions: DAMP inhibition possesses good potential as an adjuvant treatment approach in PM, as it improves clinical outcome and can be given together with the standard adjuvant dexamethasone without drug effect loss in experimental PM
Сутність та класифікація ризиків інвестиційної діяльності
Наводиться визначення поняттю "ризики інвестиційної діяльності" за рахунок поєднання його сутнісних характеристик, виконано узагальнення класифікації цих ризиків, запропоновано введення нової класифікаційної групи – "корпоративні ризики", які пов'язані з можливістю втрати контролю над підприємством інвестором-акціонером
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