bluuebunny/crossref_metadata_2025 huggingface dataset:
Association between chronic immune-mediated inflammatory diseases and cardiovascular risk
Authors: Baena-Díez Jose Miguel , Garcia-Gil Maria , Comas-Cufí Marc , Ramos Rafel , Prieto-Alhambra Daniel , Salvador-González Betlem , Elosua Roberto , Dégano Irene R , Peñafiel Judith , Grau María
Published: August 2017

Objective

To examine the association between chronic immune-mediated diseases (rheumatoid arthritis, systemic lupus erythematosus or the following chronic immune-mediated inflammatory diagnoses groups: inflammatory bowel diseases, inflammatory polyarthropathies, systemic connective tissue disorders and spondylopathies) and the 6-year coronary artery disease, stroke, cardiovascular disease incidence and overall mortality; and to estimate the population attributable fractions for all four end-points for each chronic immune-mediated inflammatory disease.

Methods

Cohort study of individuals aged 35–85 years, with no history of cardiovascular disease from Catalonia (Spain). The coded diagnoses of chronic immune-mediated diseases and cardiovascular diseases were ascertained and registered using validated codes, and date of death was obtained from administrative data. Cox regression models for each outcome according to exposure were fitted to estimate HRs in two models
1
: after adjustment for sex, age, cardiovascular risk factors and
2
further adjusted for drug use. Population attributable fractions were estimated for each exposure.

Results

Data were collected from 991 546 participants. The risk of cardiovascular disease was increased in systemic connective tissue disorders (model 1: HR=1.38 (95% CI 1.21 to 1.57) and model 2: HR=1.31 (95% CI 1.15 to 1.49)), rheumatoid arthritis (HR=1.43 (95% CI 1.26 to 1.62) and HR=1.31 (95% CI 1.15 to 1.49)) and inflammatory bowel diseases (HR=1.18 (95% CI 1.06 to 1.32) and HR=1.12 (95% CI 1.01 to 1.25)). The effect of anti-inflammatory treatment was significant in all instances (HR=1.50 (95% CI 1.24 to 1.81); HR=1.47 (95% CI 1.23 to 1.75); HR=1.43 (95% CI 1.19 to 1.73), respectively). The population attributable fractions for all three disorders were 13.4%, 15.7% and 10.7%, respectively.

Conclusion

Systemic connective tissue disorders and rheumatoid arthritis conferred the highest cardiovascular risk and population impact, followed by inflammatory bowel diseases.
Effectiveness of a nationwide intervention to increase helmet use in Dutch skiers and snowboarders: an observational cohort study
Authors: Vriend Ingrid , Hesselink Arlette , Kemler Ellen , Gouttebarge Vincent , van Mechelen Willem , Verhagen Evert
Published: August 2017

Objective

Helmet use in Dutch recreational skiers and snowboarders (DRSS) remains low. This study evaluated the effects of exposure to a nationwide intervention on relevant determinants of helmet use and helmet use in DRSS.

Methods

The intervention mapping protocol was used to develop an in-season intervention programme targeted at adult DRSS. A prospective single-cohort study was conducted to evaluate the impact of intervention exposure on determinants of helmet use (ie, knowledge about head injury risk and preventive measures, risk perception, attitudes to head injury risk and helmet use and intention to helmet use) and self-reported helmet use. A random sample of 363 DRSS from an existing panel participated in this study. Data were collected using online questionnaires before and immediately after the 2010/2011 intervention season. In a separate sample of 363 DRSS, intervention reach was assessed after the 2010/2011 season.

Results

Overall, no significant associations were found between intervention exposure and the determinants of helmet use. However, subgroup analyses revealed intervention effects on risk perception and knowledge in specific subpopulations. Intervention exposure had a significant, positive effect on helmet use in DRSS (β=0.23; 95% CI 0.017 to 0.44). Subgroup analyses revealed that this effect was found in: (1) skiers, (2) female DRSS, (3) young skiers and (4) intermediate skiers. Overall, intervention reach was 28.1%, with differences found between skiers and snowboarders.

Conclusions

Exposure to a nationwide intervention programme was associated with increased self-reported helmet use in DRSS. Differences were found in intervention effectiveness and reach between subpopulations. These differences must be taken into account when developing and evaluating future interventions.
Pitfalls in the management of peripheral vascular injuries
Authors: Feliciano David V
Published: August 2017

Over the past 65+ years, most civilian peripheral vascular injuries have been managed by trauma surgeons with training or experience in vascular repair or ligation. This is appropriate as the in-hospital trauma team is immediately available, and there are often other injuries present in the victim.

The pitfall to avoid during evaluation of the patient in the emergency center is a missed diagnosis. In the patient without ‘hard’ signs of a peripheral vascular injury, a careful history (bleeding), physical examination including measurement of ankle–brachial (ABI) or brachial–brachial index and liberal use of CT arteriography depending on an ABI <0.9 should essentially make the diagnosis if an arterial injury is present.

At operation, one pitfall is to limit skin preparation and draping, thereby eliminating the option of removing the greater saphenous vein if needed as a conduit from either the groin or ankle of an uninjured lower extremity. Another pitfall is to make a full longitudinal incision directly over a large pulsatile hematoma. Rather, separate shorter longitudinal incisions should be made to obtain proximal and distal vascular control before entering the hematoma. The failure to recognize patients who should be managed initially with insertion of a temporary intraluminal shunt is a major pitfall as well. Not following time-proven and results-proven ‘fine techniques’ of operative repair is another major pitfall. Such techniques include the following: use of small angioaccess vascular clamps or silastic vessel loops; passage of proximal and distal Fogarty catheters; administration of regional or systemic heparin during complex repairs; an open anastomosis technique; and completion arteriography after a complex arterial repair in a lower extremity.

Avoiding pitfalls should allow for success in peripheral vascular repair, particularly since most patients are young with non-diseased vessels.
Derivation and validation of a two-biomarker panel for diagnosis of ARDS in patients with severe traumatic injuries
Authors: Ware Lorraine B , Zhao Zhiguo , Koyama Tatsuki , Brown Ryan M , Semler Matthew W , Janz David R , May Addison K , Fremont Richard D , Matthay Michael A , Cohen Mitchell J , Calfee Carolyn S
Published: August 2017

Background

Acute respiratory distress syndrome (ARDS) is common after severe traumatic injuries but is underdiagnosed and undertreated. We hypothesized that a panel of plasma biomarkers could be used to diagnose ARDS in severe trauma. To test this hypothesis, we derived and validated a biomarker panel in three independent cohorts and compared the diagnostic performance to clinician recognition of ARDS.

Methods

Eleven plasma biomarkers of inflammation, lung epithelial and endothelial injury were measured in a derivation cohort of 439 severe trauma patients. ARDS status was analyzed by two-investigator consensus, and cases were required to meet Berlin criteria on intensive care unit (ICU) day 1. Controls were subjects without ARDS during the first 4 days of study enrollment. A multivariable logistic regression model was used to generate probabilities for ARDS. A reduced model with the top two performing markers was then tested in two independent validation cohorts. To assess clinical diagnosis of ARDS, medical records in the derivation cohort were systematically searched for documentation of ARDS diagnosis made by a clinical provider.

Results

Among 11 biomarkers, the combination of the endothelial injury marker angiopoietin-2 (Ang-2) and the lung epithelial injury marker receptor for advanced glycation endproducts (RAGE) provided good discrimination for ARDS in the derivation cohort (area under the curve (AUC)=0.74 (95% CI 0.67 to 0.80). In the validation cohorts, the AUCs for this model were 0.70 (0.61 to 0.77) and 0.78 (0.71 to 0.84). In contrast, provider assessment demonstrated poor diagnostic accuracy for ARDS, with AUC of 0.55 (0.51 to 0.60).

Discussion

A two-biomarker panel consisting of Ang-2 and RAGE performed well across multiple patient cohorts and outperformed clinical providers for diagnosing ARDS in severe trauma. Clinical application of this model could improve both diagnosis and treatment of ARDS in patients with severe trauma.

Level of evidence

Diagnostic study, level II.
Antimicrobial use in food‐producing animals: a rapid evidence assessment of stakeholder practices and beliefs
Authors: Hockenhull Jo , Turner Andrea E , Reyher Kristen K , Barrett David C , Jones Laura , Hinchliffe Stephen , Buller Henry J
Published: August 2017

Food‐producing animals throughout the world are likely to be exposed to antimicrobial (AM) treatment. The crossover in AM use between human and veterinary medicine raises concerns that antimicrobial resistance (AMR) may spread from food‐producing animals to humans, driving the need for further understanding of how AMs are used in livestock practice as well as stakeholder beliefs relating to their use. A rapid evidence assessment (REA) was used to collate research on AM use published in peer‐reviewed journals between 2000 and 2016. Forty‐eight papers were identified and reviewed. The summary of findings highlights a number of issues regarding current knowledge of the use of AMs in food‐producing animals and explores the attitudes of interested parties regarding the reduction of AM use in livestock. Variation between and within countries, production types and individual farms demonstrates the complexity of the challenge involved in monitoring and regulating AM use in animal agriculture. Many factors that could influence the prevalence of AMR in livestock are of concern across all sections of the livestock industry. This REA highlights the potential role of farmers and veterinarians and of other advisors, public pressure and legislation to influence change in the use of AMs in livestock.
CITY SIZE, LABOR PRODUCTIVITY AND WAGES IN KOREA
Authors: LEE BUN SONG , HONG SUNG HYO , WOHAR MARK E.
Published: August 2017

This study attempts to derive policy implications for spatially-balanced growth through empirical analysis on determinants of regional wage gaps in Korea. Combes et al. [(2008) Spatial wage disparities: Sorting Matters. Journal of Urban Economics, 63, 723–742] suggest that regional wage gaps result from the regional differences in workers’ human capital, nonhuman endowments, and agglomeration economies. The current study applies a similar two-stage estimation model to the 2006 cross-sectional data for 4009 workers from the Korean Labor Panel Survey (KLPS) performed by the Korea Labor Institute. Localization economies are positive external effects from the geographic concentration of firms in the same industry. We find evidence of localization economies in our research. The second stage estimation results for the determinants of regional wage gaps show that the average wage is higher in areas that concentrate in a small number of industries rather than in areas that are diversified with many industries. This result is in direct contrast to the findings from Combes et al. [(2008) Spatial wage disparities: Sorting Matters. Journal of Urban Economics, 63, 723–742] who analyze the French labor market data. This difference can be explained by the possibility that in Korea the improved quality of life (e.g., better education services) and/or the increase in job mobility in large diversified metropolitan areas induce workers to accept relatively lower wages in those areas. In order to resolve the bias in the estimation of the agglomeration effects caused by the heterogeneity of workers, we also performed panel regressions of the 2nd 2000 and the 7th 2005 KLPS panel data of 7431 observations. The panel regression results also support our original findings from regressions of the 8th 2006 KLPS data.
Critical temperature of pair condensation in a dilute Bose gas with spin–orbit coupling
Authors: Luo Dekun , Yin Lan
Published: August 2017

We study the Bardeen–Cooper–Shrieffer (BCS) pairing state of a two-component Bose gas with a symmetric spin–orbit coupling (SOC). In the dilute limit at low temperature, this system is essentially a dilute gas of diatomic molecules. We compute the effective mass of the molecule and find that it is anisotropic in momentum space. The critical temperature of the pairing state is about eight times smaller than the Bose–Einstein condensation (BEC) transition temperature of an ideal Bose gas with the same density.
A New Analytical Approach for Free Vibration, Buckling and Forced Vibration of Rectangular Nanoplates Based on Nonlocal Elasticity Theory
Authors: Rong Dalun , Fan Junhai , Lim C. W. , Xu Xinsheng , Zhou Zhenhuan
Published: August 2017

In this paper, an analytical Hamiltonian-based model for the dynamic analysis of rectangular nanoplates is proposed using the Kirchhoff plate theory and Eringen’s nonlocal theory. In a symplectic space, the dynamic problem is reduced to solving a unified Hamiltonian dual equation formed by a total unknown vector consisting of displacements, rotation angles, bending moments and generalized shear forces. The exact solutions for free vibration, buckling and steady state forced vibration are established by the eigenvalue analysis and expansion of eigenfunction without any trial functions. In addition, the explicit expressions of the characteristic equations, mode functions and steady state response of the nanoplate with two opposite edges that are simply supported or guided supported are obtained. To verify the accuracy and reliability of the present method, numerical results are compared with published solutions and excellent agreement is obtained. Comprehensive benchmark results that consider the nonlocal effect on the dynamic behaviors of rectangular nanoplates are also presented in dimensionless tabular and graphical forms.
Interpretation miniatures
Authors: Nikolić Hrvoje
Published: August 2017

Most physicists do not have patience for reading long and obscure interpretation arguments and disputes. Hence, to attract attention of a wider physics community, in this paper various old and new aspects of quantum interpretations are explained in a concise and simple (almost trivial) form. About the “Copenhagen” interpretation, we note that there are several different versions of it and explain how to make sense of “local nonreality” interpretation. About the many-world interpretation (MWI), we explain that it is neither local nor nonlocal, that it cannot explain the Born rule, that it suffers from the preferred basis problem, and that quantum suicide cannot be used to test it. About the Bohmian interpretation, we explain that it is analogous to dark matter, use it to explain that there is no big difference between nonlocal correlation and nonlocal causation, and use some condensed-matter ideas to outline how nonrelativistic Bohmian theory could be a theory of everything. We also explain how different interpretations can be used to demystify the delayed choice experiment, to resolve the problem of time in quantum gravity, and to provide alternatives to quantum nonlocality. Finally, we explain why is life compatible with the second law.
Efficient Family of Sixth-Order Methods for Nonlinear Models with Its Dynamics
Authors: Behl Ramandeep , Maroju Prashanth , Motsa S. S.
Published: August 2017

In this study, we design a new efficient family of sixth-order iterative methods for solving scalar as well as system of nonlinear equations. The main beauty of the proposed family is that we have to calculate only one inverse of the Jacobian matrix in the case of nonlinear system which reduces the computational cost. The convergence properties are fully investigated along with two main theorems describing their order of convergence. By using complex dynamics tools, its stability is analyzed, showing stable members of the family. From this study, we intend to have more information about these methods in order to detect those with best stability properties. In addition, we also presented a numerical work which confirms the order of convergence of the proposed family is well deduced for scalar, as well as system of nonlinear equations. Further, we have also shown the implementation of the proposed techniques on real world problems like Van der Pol equation, Hammerstein integral equation, etc.
The Analysis of Dynamic Buckling of an Impacted Column using Difference Methods
Authors: Lu Xinyang , Wu Qingbiao , Khan Yasir
Published: August 2017

In this paper, the object of our study is two coupled partial differential equation which have a rich physical background. With a reasonable change to the initial value, we use central difference method and compact finite difference method to get the numerical results of the governing equations. In the analysis of the latter, we use the Hermitian and skew-Hermitian splitting (HSS) method to solve a large sparse non-Hermitian positive definite system of linear equations. In this way, the computational efficiency can be improved and the convergence is guaranteed which is proved by Bai [Bai et al. [2003] “Hermitian and skew-Hermitian splitting methods for non-Hermitian positive definite linear systems,” SIAM J. Matrix Anal. Appl. 24, 603–626] and Chen [Chen et al. [2014] “Convergence analysis of the modified Newton-HSS method under the Hölder continuous condition,” J. Comput. Appl. Math. 264, 115–130]. And we also pay attention to the effect of initial conditions, on which we add a small perturbation to observe its influence by comparing numerical results.
The universal n-pointed surface bundle only has n sections
Authors: Chen Lei
Published: August 2017

The classifying space BDiff[Formula: see text] of the orientation-preserving diffeomorphism group of a surface [Formula: see text] of genus [Formula: see text] fixing [Formula: see text] points pointwise has a universal bundle [Formula: see text] The [Formula: see text] fixed points provide [Formula: see text] sections [Formula: see text] of [Formula: see text]. In this paper we prove a conjecture of R. Hain that any section of [Formula: see text] is homotopic to some [Formula: see text]. Let [Formula: see text] be the space of ordered [Formula: see text]-tuple of distinct points on [Formula: see text]. As part of the proof of Hain’s conjecture, we prove a result of independent interest: any surjective homomorphism [Formula: see text] is equal to one of the forgetful homomorphisms [Formula: see text], possibly post-composed with an automorphism of [Formula: see text]. We also classify sections of the universal hyperelliptic surface bundle.
Streaming Tree Transducers
Authors: Alur Rajeev , D'antoni Loris
Published: August 2017

The theory of tree transducers provides a foundation for understanding expressiveness and complexity of analysis problems for specification languages for transforming hierarchically structured data such as XML documents. We introduce
streaming tree transducers
as an analyzable, executable, and expressive model for transforming unranked ordered trees (and forests) in a single pass. Given a linear encoding of the input tree, the transducer makes a single left-to-right pass through the input, and computes the output in linear time using a finite-state control, a visibly pushdown stack, and a finite number of variables that store output chunks that can be combined using the operations of string-concatenation and tree-insertion. We prove that the expressiveness of the model coincides with transductions definable using monadic second-order logic (MSO). Existing models of tree transducers either cannot implement all MSO-definable transformations, or require
regular look-ahead
that prohibits single-pass implementation. We show a variety of analysis problems such as
type-checking
and checking
functional equivalence
are decidable for our model.
An Average-Case Depth Hierarchy Theorem for Boolean Circuits
Authors: Håstad Johan , Rossman Benjamin , Servedio Rocco A. , Tan Li-Yang
Published: August 2017

We prove an average-case depth hierarchy theorem for Boolean circuits over the standard basis of AND, OR, and NOT gates. Our hierarchy theorem says that for every
d
≥ 2, there is an explicit
n
-variable Boolean function
f
, computed by a linear-size depth-
d
formula, which is such that any depth-(
d
−1) circuit that agrees with
f
on (1/2 +
o

n

(1)) fraction of all inputs must have size exp(
n
Ω (1/d)
). This answers an open question posed by Håstad in his Ph.D. thesis (Håstad 1986b).

Our average-case depth hierarchy theorem implies that the polynomial hierarchy is infinite relative to a random oracle with probability 1, confirming a conjecture of Håstad (1986a), Cai (1986), and Babai (1987). We also use our result to show that there is no “approximate converse” to the results of Linial, Mansour, Nisan (Linial et al. 1993) and (Boppana 1997) on the total influence of bounded-depth circuits.

A key ingredient in our proof is a notion of
random projections
which generalize random restrictions.
Local Representative-Based Matrix Factorization for Cold-Start Recommendation
Authors: Shi Lei , Zhao Wayne Xin , Shen Yi-Dong
Published: August 2017

Cold-start recommendation is one of the most challenging problems in recommender systems. An important approach to cold-start recommendation is to conduct an interview for new users, called the
interview-based approach
. Among the interview-based methods, Representative-Based Matrix Factorization (RBMF) [24] provides an effective solution with appealing merits: it represents users over selected representative items, which makes the recommendations highly intuitive and interpretable. However, RBMF only utilizes a global set of representative items to model all users. Such a representation is somehow too strict and may not be flexible enough to capture varying users’ interests. To address this problem, we propose a novel interview-based model to dynamically create meaningful user groups using decision trees and then select local representative items for different groups. A two-round interview is performed for a new user. In the first round, l
1
global questions are issued for group division, while in the second round, l
2
local-group-specific questions are given to derive local representation. We collect the feedback on the (l
1
+l
2
) items to learn the user representations. By putting these steps together, we develop a joint optimization model, named
local representative-based matrix factorization
, for new user recommendations. Extensive experiments on three public datasets have demonstrated the effectiveness of the proposed model compared with several competitive baselines.
Herbarium Racketensis: a stroll through the woods (functional pearl)
Authors: St-Amour Vincent , Feltey Daniel , Florence Spencer P. , You Shu-Hung , Findler Robert Bruce
Published: August 2017

Domain-specific languages are the ultimate abstraction, dixit Paul Hudak. But what abstraction should we use to build such ultimate abstractions? What is sauce for the goose is sauce for the gander: a language, of course!

Racket is the ultimate abstraction-abstraction, a platform for quickly and easily building new ultimate abstractions. This pearl demonstrates Racket's power by taking a leisurely walk through the implementation of a DSL for Lindenmayer systems, the computational model par excellence of theoretical botany.
Testing and debugging functional reactive programming
Authors: Perez Ivan , Nilsson Henrik
Published: August 2017

Many types of interactive applications, including video games, raise particular challenges when it comes to testing and debugging. Reasons include de-facto lack of reproducibility and difficulties of automatically generating suitable test data. This paper demonstrates that certain variants of Functional Reactive Programming (FRP) implemented in pure functional languages can mitigate such difficulties by offering referential transparency at the level of whole programs. This opens up for a multi-pronged approach for assisting with testing and debugging that works across platforms, including assertions based on temporal logic, recording and replaying of runs (also from deployed code), and automated random testing using QuickCheck. The approach has been validated on real, non-trivial games implemented in the FRP system Yampa through a tool providing a convenient Graphical User Interface that allows the execution of the code under scrutiny to be controlled, moving along the execution time line, and pin-pointing of violations of assertions on PCs as well as mobile platforms.
Lock-step simulation is child's play (experience report)
Authors: Breitner Joachim , Smith Chris
Published: August 2017

Implementing multi-player networked games by broadcasting the player’s input and letting each client calculate the game state -- a scheme known as *lock-step simulation* – is an established technique. However, ensuring that every client in this scheme obtains a consistent state is infamously hard and in general requires great discipline from the game programmer. The thesis of this pearl is that in the realm of functional programming – in particular with Haskell's purity and static pointers – this hard problem becomes almost trivially easy.

We support this thesis by implementing lock-step simulation under very adverse conditions. We extended the educational programming environment CodeWorld, which is used to teach math and programming to middle school students, with the ability to create and run interactive, networked multi-user games. Despite providing a very abstract and high-level interface, and without requiring any discipline from the programmer, we can provide consistent lock-step simulation with client prediction.
A pretty but not greedy printer (functional pearl)
Authors: Bernardy Jean-Philippe
Published: August 2017

This paper proposes a new specification of pretty printing which is stronger than the state of the art: we require the output to be the shortest possible, and we also offer the ability to align sub-documents at will. We argue that our specification precludes a greedy implementation. Yet, we provide an implementation which behaves linearly in the size of the output. The derivation of the implementation demonstrates functional programming methodology.
A unified approach to solving seven programming problems (functional pearl)
Authors: Byrd William E. , Ballantyne Michael , Rosenblatt Gregory , Might Matthew
Published: August 2017

We present seven programming challenges in Racket, and an elegant, unified approach to solving them using constraint logic programming in miniKanren.
Abstracting definitional interpreters (functional pearl)
Authors: Darais David , Labich Nicholas , Nguyen Phúc C. , Van Horn David
Published: August 2017

In this functional pearl, we examine the use of definitional interpreters as a basis for abstract interpretation of higher-order programming languages. As it turns out, definitional interpreters, especially those written in monadic style, can provide a nice basis for a wide variety of collecting semantics, abstract interpretations, symbolic executions, and their intermixings.

But the real insight of this story is a replaying of an insight from Reynold's landmark paper,
Definitional Interpreters for Higher-Order Programming Languages
, in which he observes definitional interpreters enable the defined-language to inherit properties of the defining-language. We show the same holds true for definitional
abstract
interpreters. Remarkably, we observe that abstract definitional interpreters can inherit the so-called “pushdown control flow” property, wherein function calls and returns are precisely matched in the abstract semantics, simply by virtue of the function call mechanism of the defining-language.

The first approaches to achieve this property for higher-order languages appeared within the last ten years, and have since been the subject of many papers. These approaches start from a state-machine semantics and uniformly involve significant technical engineering to recover the precision of pushdown control flow. In contrast, starting from a definitional interpreter, the pushdown control flow property is inherent in the meta-language and requires no further technical mechanism to achieve.
On the expressive power of user-defined effects: effect handlers, monadic reflection, delimited control
Authors: Forster Yannick , Kammar Ohad , Lindley Sam , Pretnar Matija
Published: August 2017

We compare the expressive power of three programming abstractions for user-defined computational effects: Plotkin and Pretnar's effect handlers, Filinski's monadic reflection, and delimited control without answer-type-modification. This comparison allows a precise discussion about the relative expressiveness of each programming abstraction. It also demonstrates the sensitivity of the relative expressiveness of user-defined effects to seemingly orthogonal language features.

We present three calculi, one per abstraction, extending Levy's call-by-push-value. For each calculus, we present syntax, operational semantics, a natural type-and-effect system, and, for effect handlers and monadic reflection, a set-theoretic denotational semantics. We establish their basic metatheoretic properties: safety, termination, and, where applicable, soundness and adequacy. Using Felleisen's notion of a macro translation, we show that these abstractions can macro-express each other, and show which translations preserve typeability. We use the adequate finitary set-theoretic denotational semantics for the monadic calculus to show that effect handlers cannot be macro-expressed while preserving typeability either by monadic reflection or by delimited control. Our argument fails with simple changes to the type system such as polymorphism and inductive types. We supplement our development with a mechanised Abella formalisation.
Imperative functional programs that explain their work
Authors: Ricciotti Wilmer , Stolarek Jan , Perera Roly , Cheney James
Published: August 2017

Program slicing provides explanations that illustrate how program outputs were produced from inputs. We build on an approach introduced in prior work, where dynamic slicing was defined for pure higher-order functional programs as a Galois connection between lattices of partial inputs and partial outputs. We extend this approach to
imperative functional programs
that combine higher-order programming with references and exceptions. We present proofs of correctness and optimality of our approach and a proof-of-concept implementation and experimental evaluation.
Effect-driven QuickChecking of compilers
Authors: Midtgaard Jan , Justesen Mathias Nygaard , Kasting Patrick , Nielson Flemming , Nielson Hanne Riis
Published: August 2017

How does one test a language implementation with QuickCheck (aka. property-based testing)? One approach is to generate programs following the grammar of the language. But in a statically-typed language such as OCaml too many of these candidate programs will be rejected as ill-typed by the type checker. As a refinement Pałka et al. propose to generate programs in a goal-directed, bottom-up reading up of the typing relation. We have written such a generator. However many of the generated programs has output that depend on the evaluation order, which is commonly under-specified in languages such as OCaml, Scheme, C, C++, etc. In this paper we develop a type and effect system for conservatively detecting evaluation-order dependence and propose its goal-directed reading as a generator of programs that are independent of evaluation order. We illustrate the approach by generating programs to test OCaml's two compiler backends against each other and report on a number of bugs we have found doing so.
A specification for dependent types in Haskell
Authors: Weirich Stephanie , Voizard Antoine , de Amorim Pedro Henrique Azevedo , Eisenberg Richard A.
Published: August 2017

We propose a core semantics for Dependent Haskell, an extension of Haskell with full-spectrum dependent types. Our semantics consists of two related languages. The first is a Curry-style dependently-typed language with nontermination, irrelevant arguments, and equality abstraction. The second, inspired by the Glasgow Haskell Compiler's core language FC, is its explicitly-typed analogue, suitable for implementation in GHC. All of our results---chiefly, type safety, along with theorems that relate these two languages---have been formalized using the Coq proof assistant. Because our work is backwards compatible with Haskell, our type safety proof holds in the presence of nonterminating computation. However, unlike other full-spectrum dependently-typed languages, such as Coq, Agda or Idris, because of this nontermination, Haskell's term language does not correspond to a consistent logic.
A metaprogramming framework for formal verification
Authors: Ebner Gabriel , Ullrich Sebastian , Roesch Jared , Avigad Jeremy , de Moura Leonardo
Published: August 2017

We describe the metaprogramming framework currently used in Lean, an interactive theorem prover based on dependent type theory. This framework extends Lean's object language with an API to some of Lean's internal structures and procedures, and provides ways of reflecting object-level expressions into the metalanguage. We provide evidence to show that our implementation is performant, and that it provides a convenient and flexible way of writing not only small-scale interactive tactics, but also more substantial kinds of automation.
Chaperone contracts for higher-order sessions
Authors: Melgratti Hernán , Padovani Luca
Published: August 2017

Contracts have proved to be an effective mechanism that helps developers in identifying those modules of a program that violate the contracts of the functions and objects they use. In recent years, sessions have established as a key mechanism for realizing inter-module communications in concurrent programs. Just like values flow into or out of a function or object, messages are sent on, and received from, a session endpoint. Unlike conventional functions and objects, however, the kind, direction, and properties of messages exchanged in a session may vary over time, as the session progresses. This feature of sessions calls for contracts that evolve along with the session they describe.

In this work, we extend to sessions the notion of chaperone contract (roughly, a contract that applies to a mutable object) and investigate the ramifications of contract monitoring in a higher-order language that features sessions. We give a characterization of correct module, one that honors the contracts of the sessions it uses, and prove a blame theorem. Guided by the calculus, we describe a lightweight implementation of monitored sessions as an OCaml module with which programmers can benefit from static session type checking and dynamic contract monitoring using an off-the-shelf version of OCaml.
Whip: higher-order contracts for modern services
Authors: Waye Lucas , Chong Stephen , Dimoulas Christos
Published: August 2017

Modern service-oriented applications forgo semantically rich protocols and middleware when composing services. Instead, they embrace the loosely-coupled development and deployment of services that communicate via simple network protocols. Even though these applications do expose interfaces that are
higher-order
in spirit, the simplicity of the network protocols forces them to rely on brittle low-level encodings. To bridge the apparent semantic gap, programmers introduce ad-hoc and error-prone defensive code. Inspired by Design by Contract, we choose a different route to bridge this gap. We introduce Whip, a contract system for modern services. Whip (i) provides programmers with a
higher-order contract language
tailored to the needs of modern services; and (ii) monitors services at run time to detect services that do not live up to their advertised interfaces. Contract monitoring is local to a service. Services are treated as black boxes, allowing heterogeneous implementation languages without modification to services' code. Thus, Whip does not disturb the loosely coupled nature of modern services.
Manifest sharing with session types
Authors: Balzer Stephanie , Pfenning Frank
Published: August 2017

Session-typed languages building on the Curry-Howard isomorphism between linear logic and session-typed communication guarantee session fidelity and deadlock freedom. Unfortunately, these strong guarantees exclude many naturally occurring programming patterns pertaining to shared resources. In this paper, we introduce sharing into a session-typed language where types are stratified into linear and shared layers with modal operators connecting the layers. The resulting language retains session fidelity but not the absence of deadlocks, which can arise from contention for shared processes. We illustrate our language on various examples, such as the dining philosophers problem, and provide a translation of the untyped asynchronous π-calculus into our language.
Theorems for free for free: parametricity, with and without types
Authors: Ahmed Amal , Jamner Dustin , Siek Jeremy G. , Wadler Philip
Published: August 2017

The polymorphic blame calculus integrates static typing, including universal types, with dynamic typing. The primary challenge with this integration is preserving parametricity: even dynamically-typed code should satisfy it once it has been cast to a universal type. Ahmed et al. (2011) employ runtime type generation in the polymorphic blame calculus to preserve parametricity, but a proof that it does so has been elusive. Matthews and Ahmed (2008) gave a proof of parametricity for a closely related system that combines ML and Scheme, but later found a flaw in their proof. In this paper we present an improved version of the polymorphic blame calculus and we prove that it satisfies relational parametricity. The proof relies on a step-indexed Kripke logical relation. The step-indexing is required to make the logical relation well-defined in the case for the dynamic type. The possible worlds include the mapping of generated type names to their types and the mapping of type names to relations. We prove the Fundamental Property of this logical relation and that it is sound with respect to contextual equivalence. To demonstrate the utility of parametricity in the polymorphic blame calculus, we derive two free theorems.
On polymorphic gradual typing
Authors: Igarashi Yuu , Sekiyama Taro , Igarashi Atsushi
Published: August 2017

We study an extension of gradual typing—a method to integrate dynamic typing and static typing smoothly in a single language—to parametric polymorphism and its theoretical properties, including conservativity of typing and semantics over both statically and dynamically typed languages, type safety, blame-subtyping theorem, and the gradual guarantee—the so-called refined criteria, advocated by Siek et al. We develop System F

G

, which is a gradually typed extension of System F with the dynamic type and a new type consistency relation, and translation to a new polymorphic blame calculus System F

C

, which is based on previous polymorphic blame calculi by Ahmed et al. The design of System F

G

and System F

C

, geared to the criteria, is influenced by the distinction between static and gradual type variables, first observed by Garcia and Cimini. This distinction is also useful to execute statically typed code without incurring additional overhead to manage type names as in the prior calculi. We prove that System F

G

satisfies most of the criteria: all but the hardest property of the gradual guarantee on semantics. We show that a key conjecture to prove the gradual guarantee leads to the Jack-of-All-Trades property, conjectured as an important property of the polymorphic blame calculus by Ahmed et al.
Inferring scope through syntactic sugar
Authors: Pombrio Justin , Krishnamurthi Shriram , Wand Mitchell
Published: August 2017

Many languages use syntactic sugar to define parts of their surface language in terms of a smaller core. Thus some properties of the surface language, like its
scoping rules
, are not immediately evident. Nevertheless, IDEs, refactorers, and other tools that traffic in source code depend on these rules to present information to users and to soundly perform their operations. In this paper, we show how to lift scoping rules defined on a core language to rules on the surface, a process of
scope inference
. In the process we introduce a new representation of binding structure---scope as a preorder---and present a theoretical advance: proving that a desugaring system preserves α-equivalence even though scoping rules have been provided
only
for the core language. We have also implemented the system presented in this paper.
How Elearning Practitioners can Find Value in Augmented and Virtual Reality Technology
Authors: Manjorin Jeremy
Published: August 2017

This book review of Practical Augmented Reality written by Steve Aukstakalnis explores the practical side of augmented and virtual realities for the professional learner.
Neuronal-Glial Interactions Maintain Chronic Neuropathic Pain after Spinal Cord Injury
Authors: Gwak Young S. , Hulsebosch Claire E. , Leem Joong Woo
Published: August 2017

The hyperactive state of sensory neurons in the spinal cord enhances pain transmission. Spinal glial cells have also been implicated in enhanced excitability of spinal dorsal horn neurons, resulting in pain amplification and distortions. Traumatic injuries of the neural system such as spinal cord injury (SCI) induce neuronal hyperactivity and glial activation, causing maladaptive synaptic plasticity in the spinal cord. Recent studies demonstrate that SCI causes persistent glial activation with concomitant neuronal hyperactivity, thus providing the substrate for central neuropathic pain. Hyperactive sensory neurons and activated glial cells increase intracellular and extracellular glutamate, neuropeptides, adenosine triphosphates, proinflammatory cytokines, and reactive oxygen species concentrations, all of which enhance pain transmission. In addition, hyperactive sensory neurons and glial cells overexpress receptors and ion channels that maintain this enhanced pain transmission. Therefore, post-SCI neuronal-glial interactions create maladaptive synaptic circuits and activate intracellular signaling events that permanently contribute to enhanced neuropathic pain. In this review, we describe how hyperactivity of sensory neurons contributes to the maintenance of chronic neuropathic pain via neuronal-glial interactions following SCI.
A Novel Approach to Determine the Prevalence of Type of Soft Palate Using Digital Intraoral Impression
Authors: Chaturvedi Saurabh , Khaled Addas Mohamed , Al Humaidi Abdullah Saad Ali , Al Qahtani Abdulrazaq Mohammed , Al Qahtani Mubarak Daghash
Published: August 2017

Aim. To determine the prevalence of type of soft palate in targeted population. Materials and Methods. Using computer technology in dentistry, intraoral digital scanner, and 3D analysis software tool, study was conducted. 100 patients selected from the outpatient clinics were divided into two groups based on the ages of 20–40 years and 41–60 years with equal ratio of males and females. Each selected patient’s maxillary arch was scanned with intraoral scanner; images so obtained were sectioned in anteroposterior cross section and with the 3D analysis software; the angulation between hard and soft palate was determined. Results. The prevalence of type II soft palate (angulation between hard and soft palate is between 10 and 45 degrees) was highest, 60% in group 1 and 44% in group 2. The difference between genders was statistically significant with p value <0.05 in both the groups, although females had higher angulation compared to the males in all classes of both groups. Conclusions. In targeted population of Aseer Province, Saudi Arabia, the prevalence of type II soft palate was more common, with higher soft palate angulation among females. The advanced age had no effect in the type of soft palate in the region.
The Perturbed Riemann Problem for Special Keyfitz-Kranzer System with Three Piecewise Constant States
Authors: Jiang Yuhao , Shen Chun
Published: August 2017

The Riemann problem for a special Keyfitz-Kranzer system is investigated and then seven different Riemann solutions are constructed. When the initial data are chosen as three piecewise constant states under suitable assumptions, the global solutions to the perturbed Riemann problem are constructed explicitly by studying all occurring wave interactions in detail. Furthermore, the stabilities of solutions are obtained under the specific small perturbations of Riemann initial data.
Laser‐Induced Color Marking of Titanium: A Modeling Study of the Interference Effect and the Impact of Protective Coating
Authors: Łęcka K. M. , Wójcik M. R. , Antończak A. J.
Published: August 2017

Laser‐induced color marking of metals, due to numerous advantages, including inter alia the high quality, resolution, durability, and noncontact methodology of surface marking, seems to be attractive for use in various applications. In this method, the resulting color is mainly evident from the interference effect. Therefore, one of the still unsolved problems on titanium is the color change after imposition of an additional layer (fingerprints, grease, etc.). In this paper, a computer simulation based on the theoretical thin layers model was presented. The results of the modeling study revealed that theoretically a thin protective coating of a known refractive index can be applied while still maintaining the target color. In this case, as a protective layer, an amphiphobic coating has been taken into consideration with its ability to resist surface contamination. The study was performed for titanium (grade 2). The model utilizes the real data derived from the spectrophotometer, as well as from the ellipsometry measurements of laser‐induced samples.
Iatrogenic IVC Perforation after Successful Catheter-Directed Thrombolysis
Authors: Firoozi Ata , Moosavi Jamal , Shafe Omid , Sadeghipour Parham
Published: August 2017

Central vein perforation as a rare complication of venous interventions is considered a nightmare if occurring in thoracic cage but behaves benignly in abdominal or pelvic region. This is not a rule, as we unfortunately encountered during the procedure of venous intervention in our patient. Although mechanical control of iatrogenic perforation or rupture is the first and most critical step during interventional procedures, the importance of anticoagulant and thrombolytic agents reversal should not be overlooked.