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In recent years, we have seen several new models of dependent type theory extended with some form of modal necessity operator, including nominal type theory, guarded and clocked type theory and spatial and cohesive type theory. In this paper, we study modal dependent type theory: dependent type theory with an operator satisfying (a dependent version of) the K axiom of modal logic. We investigate both semantics and syntax. For the semantics, we introduce categories with families with a dependent right adjoint (CwDRA) and show that the examples above can be presented as such. Indeed, we show that any category with finite limits and an adjunction of endofunctors give rise to a CwDRA via the local universe construction. For the syntax, we introduce a dependently typed extension of Fitch-style modal λ-calculus, show that it can be interpreted in any CwDRA, and build a term model. We extend the syntax and semantics with universes.
In recent years, several initiatives have sought to encourage redemption of food assistance benefits at direct-to-consumer (DTC) market venues such as community supported agriculture programs and farmers’ markets in the USA, with the dual goal of increasing access to healthy foods for low-income families and sales of locally-grown foods for farmers. Proponents of these interventions assert that these programs have a positive impact on local economies yet there is limited evidence to validate this argument. This research project used a customized input-output model to simulate potential economic impacts of programs and policies that enable Supplemental Nutrition Assistance Program (SNAP) recipients to shift purchases from traditional food retailers to DTC venues in four states. Two different scenarios were explored: (1) increased outreach to low-income consumers and (2) financial support for using SNAP benefits at DTC market channels. We found a positive, though modest, economic impact at the state level under both scenarios when accounting for (a) business losses in the food retail and wholesale sectors, (b) a shift in acreage from commodity to specialty crops and (c) the cost to taxpayers. Since most of the increased economic activity would be in the produce farming sector, we discuss the opportunities and challenges for this sector along with potential policy implications.
Background: Persistent high-risk human papillomavirus (HPV) infection is a necessary prerequisite for development of cervical cancer and its precursor lesion, high-grade squamous intraepithelial lesion (HSIL). However, HPV infection is not sufficient to drive this process, and genetic and environmental factors may also play a role. Methods/Design: The Cervical Cancer, Genetics and Environment Twin Study was established to investigate the environmental and genetic influences on variation in susceptibility to cervical pre-cancer in 25- to 69-year-old monozygotic (MZ) and dizygotic (DZ) twins recruited through the Australian Twin Registry. Reviews of Papanicolaou (Pap) screening histories were undertaken to identify individual women with a history of an abnormal Pap test. This was followed by detection of HPV in archival Pap smears of selected twin pairs to determine HPV persistence. Selected twin pairs also completed a detailed questionnaire on socio-demographic characteristics, sexual behavior, and HPV knowledge. In future analyses, under the assumptions of the classical twin design, case-wise concordance for persistent HPV infection and HSIL will be calculated for MZ and DZ twin pairs, and twin pairs (both MZ and DZ) who are discordant for the above outcomes will be used to assess the contributions of measured environmental risk factors. Discussion: The study examines factors related to HPV persistence and development of HSIL among female MZ and DZ twins. The results will contribute to our understanding of the natural history of cervical HPV infection and the relative contributions of genetic and environmental factors in disease progression.
Recent studies point to overlap between neuropsychiatric disorders in symptomatology and genetic aetiology.
To systematically investigate genomics overlap between childhood and adult attention-deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD) and major depressive disorder (MDD).
Analysis of whole-genome blood gene expression and genetic risk scores of 318 individuals. Participants included individuals affected with adult ADHD (n = 93), childhood ADHD (n = 17), MDD (n = 63), ASD (n = 51), childhood dual diagnosis of ADHD–ASD (n = 16) and healthy controls (n = 78).
Weighted gene co-expression analysis results reveal disorder-specific signatures for childhood ADHD and MDD, and also highlight two immune-related gene co-expression modules correlating inversely with MDD and adult ADHD disease status. We find no significant relationship between polygenic risk scores and gene expression signatures.
Our results reveal disorder overlap and specificity at the genetic and gene expression level. They suggest new pathways contributing to distinct pathophysiology in psychiatric disorders and shed light on potential shared genomic risk factors.
Surgical site infections (SSIs) are a leading cause of morbidity and mortality among women undergoing cesarean section (C-section), a common procedure in North America. While risk factors for SSI are often modifiable, wide variation in clinical practice exists. With this review, we provide a comprehensive overview of the results and quality of systematic reviews and meta-analyses on interventions to reduce surgical site infections among women undergoing C-section.
We searched PubMed and the Cochrane Database of Systematic Reviews for systematic reviews and meta-analyses published between January 2000 and May 2014 on interventions to reduce the occurrence of SSIs (incisional infections and endometritis), among women undergoing C-section. We extracted data on the interventions, outcomes, and strength of evidence as determined by the original article authors, and assessed the quality of each article based on a modified Assessment of Multiple Systematic Reviews tool.
A total of 30 review articles met inclusion criteria and were reviewed. Among these articles, 77 distinct interventions were evaluated: 29% were supported with strong evidence as assessed by the original article authors, and 83% of the reviews articles were classified as good quality based on our assessment. Ten interventions were classified as being effective in reducing SSI with strong evidence in a good-quality article, including preoperative vaginal cleansing, the use of perioperative antibiotic prophylaxis, and several surgical techniques.
Efforts to reduce SSI rates among women undergoing C-section should include interventions such as preoperative vaginal cleansing and the use of perioperative antibiotics because compelling evidence exists to support their effectiveness.
We apply cross-correlation to Pléiades satellite images to generate accurate, high-resolution monthly surface velocity maps of Monte Tronador glaciers between March and June 2012. Measured surface displacements cover periods as short as 19 days, with a precision of ∼0.58 m (11 m a−1). These glaciers follow a radial flow pattern, with maximum surface speeds of ∼390 m a−1 associated with steep icefalls. The lower reaches of the debris-covered tongues of Verde and Casa Pangue glaciers are almost stagnant, whereas Ventisquero Negro, another debris-covered glacier, shows acceleration at the front due to calving into a proglacial lake. Low-elevation debris-covered glacier tongues show increasing velocities at the beginning of the accumulation season, whereas higher-elevation, clean-ice tongues reduce their speed during this period. This contrasting behavior is probably in response to an increase in water input to the subglacial system from winter rainfall events at low elevations and a decrease in meltwater production at higher elevations. These sequential velocity maps can help to identify the controls on glacier surface velocity, aid in the delimitation of ice divides and could also contribute to more realistic calibration of ice-flux-mass–balance models in this glacierized area.
Mandatory influenza vaccination is associated with improved healthcare personnel vaccination rates, but institutional barriers to implementation and enforcement are reported. We explored barriers and facilitators to mandatory vaccination among a national sample of hospital administrators. Support from employees and administration were cited as key to the success of a mandate.
This is the second of two papers in which we estimate transition probabilities amongst levels of disability as defined in the Australian Survey of Disability, Ageing and Carers. In this paper we describe our estimation procedure, followed by its implementation, discussion of results and graduation of the estimated transition probabilities.
Correct handling of names and binders is an important issue in meta-programming. This paper presents an embedding of constraint logic programming into the αML functional programming language, which provides a provably correct means of implementing proof search computations over inductive definitions involving names and binders modulo α-equivalence. We show that the execution of proof search in the αML operational semantics is sound and complete with regard to the model-theoretic semantics of formulae, and develop a theory of contextual equivalence for the subclass of αML expressions which correspond to inductive definitions and formulae. In particular, we prove that αML expressions, which denote inductive definitions, are contextually equivalent precisely when those inductive definitions have the same model-theoretic semantics. This paper is a revised and extended version of the conference paper (Lakin, M. R. & Pitts, A. M. (2009) Resolving inductive definitions with binders in higher-order typed functional programming. In Proceedings of the 18th European Symposium on Programming (ESOP 2009), Castagna, G. (ed), Lecture Notes in Computer Science, vol. 5502. Berlin, Germany: Springer-Verlag, pp. 47–61) and draws on material from the first author's PhD thesis (Lakin, M. R. (2010) An Executable Meta-Language for Inductive Definitions with Binders. University of Cambridge, UK).
This is a book about names and symmetry in the part of computer science that has to do with programming languages. Although symmetry plays an important role in many branches of mathematics and physics, its relevance to computer science may not be so clear to the reader. This introduction explains the computer science motivation for a theory of names based upon symmetry and provides a guide to what follows.
Names are used in many different ways in computer systems and in the formal languages used to describe and construct them. This book is exclusively concerned with what Needham calls ‘pure names’:
A pure name is nothing but a bit-pattern that is an identifier, and is only useful for comparing for identity with other such bit-patterns – which includes looking up in tables to find other information. The intended contrast is with names which yield information by examination of the names themselves, whether by reading the text of the name or otherwise. […] like most good things in computer science, pure names help by putting in an extra stage of indirection; but they are not much good for anything else.
(Needham, 1989, p. 90)
We prefer to use the adjective ‘atomic’ rather than ‘pure’, because for this kind of name, internal structure is irrelevant; their only relevant attribute is their identity. Although such names may not be much good for anything other than indirection, that one thing is a hugely important and very characteristic aspect of computer science.
Nominal sets provide a promising new mathematical analysis of names in formal languages based upon symmetry, with many applications to the syntax and semantics of programming language constructs that involve binding, or localising names. Part I provides an introduction to the basic theory of nominal sets. In Part II, the author surveys some of the applications that have developed in programming language semantics (both operational and denotational), functional programming and logic programming. As the first book to give a detailed account of the theory of nominal sets, it will be welcomed by researchers and graduate students in theoretical computer science.