bluuebunny/crossref_metadata_2025 huggingface dataset:
The current provision of community-based teaching in UK medical schools: an online survey and systematic review
Authors: Lee Sandra W W , Clement Naomi , Tang Natalie , Atiomo William
Published: December 2014

Objective

To evaluate the current provision and outcome of community-based education (CBE) in UK medical schools.

Design and data sources

An online survey of UK medical school websites and course prospectuses and a systematic review of articles from PubMed and Web of Science were conducted. Articles in the systematic review were assessed using Rossi, Lipsey and Freeman's approach to programme evaluation.

Study selection

Publications from November 1998 to 2013 containing information related to community teaching in undergraduate medical courses were included.

Results

Out of the 32 undergraduate UK medical schools, one was excluded due to the lack of course specifications available online. Analysis of the remaining 31 medical schools showed that a variety of CBE models are utilised in medical schools across the UK. Twenty-eight medical schools (90.3%) provide CBE in some form by the end of the first year of undergraduate training, and 29 medical schools (93.5%) by the end of the second year. From the 1378 references identified, 29 papers met the inclusion criteria for assessment. It was found that CBE mostly provided advantages to students as well as other participants, including GP tutors and patients. However, there were a few concerns regarding the lack of GP tutors’ knowledge in specialty areas, the negative impact that CBE may have on the delivery of health service in education settings and the cost of CBE.

Conclusions

Despite the wide variations in implementation, community teaching was found to be mostly beneficial. To ensure the relevance of CBE for ‘Tomorrow's Doctors’, a national framework should be established, and solutions sought to reduce the impact of the challenges within CBE.

Strengths and limitations of this study

This is the first study to review how community-based education is currently provided throughout Medical Schools in the UK. The use of Rossi, Lipsey and Freeman's method of programme evaluation means that the literature was analysed in a consistent and comprehensive way. However, a weakness is that data from the online survey was obtained from online medical school prospectuses. This means the data may be incomplete or out of date. Data in the literature review may also be skewed by publication bias.
Accuracy of the days’ supply and the number of refills allowed recorded in Québec prescription claims databases for inhaled corticosteroids
Authors: Blais Lucie , Vilain Anne , Kettani Fatima-Zohra , Forget Amélie , Lalonde Geneviève , Beauchesne Marie-France , Ducharme Francine M , Lemière Catherine
Published: November 2014

Objectives and hypotheses

Adherence to inhaled corticosteroids (ICS) is a major issue in asthma. This study aimed to estimate the accuracy of the days’ supply and number of refills allowed, variables recorded in Québec claims databases and used to estimate adherence, and to develop correction factors, if required. We hypothesised that the accuracy of the days’ supply for ICS would be low whereas the accuracy of the number of refills allowed would be high.

Setting

40 community pharmacies in Québec (Canada) and a medication registry.

Participants

We collected data for 1108 ICS original prescriptions stored in the 40 pharmacies (sample 1), and we obtained a second sample of 2676 ICS prescriptions selected from reMed, a medication registry (sample 2).

Primary and secondary outcomes

We estimated the concordance of the days’ supply and number of refills between Québec claims databases and the original prescription from sample 1. We developed a correction factor for the days’ supply in sample 1 and validated it in sample 2. Analyses were stratified by age: 0–11 and 12–64 years.

Results

In sample 1, the concordance for the days’ supply was 39.6% (95% CI 37.6% to 41.6%) in those aged 0–11 years and 56% (54.9% to 57.2%) in those aged 12–64 years. The concordance increased to 59.4% (58.2% to 60.5%) in those aged 0–11 years and 74.2% (73.5% to 74.9%) in those aged 12–64 years after applying the correction factors in sample 2. The concordance for the refills allowed was 92.1% (91% to 93.1%) in those aged 0–11 years and 93.1% (92.5% to 93.7%) in those aged 12–64 years in sample 1.

Conclusions

The accuracy of the days’ supply was moderate among those aged 0–11 years and substantial among those aged 12–64 years after applying the correction factors. The accuracy of the number of refills was almost perfect in both groups.
Improving physical functional and quality of life in older adults with multiple sclerosis via a DVD-delivered exercise intervention: a study protocol
Authors: Wójcicki Thomas R , Roberts Sarah A , Learmonth Yvonne C , Hubbard Elizabeth A , Kinnett-Hopkins Dominque , Motl Robert W , McAuley Edward
Published: December 2014

Introduction

There is a need to identify innovative, low-cost and broad-reaching strategies for promoting exercise and improving physical function in older adults with multiple sclerosis (MS).

Methods and analysis

This randomised controlled pilot trial will test the efficacy of a 6-month, DVD-delivered exercise intervention to improve functional performance and quality of life in older adults with MS. Participants will be randomised either into a DVD-delivered exercise condition or an attentional control condition. This novel approach to programme delivery provides participants with detailed exercise instructions which are presented in a progressive manner and includes a variety of modifications to better meet varying levels of physical abilities. The targeted exercises focus on three critical elements of functional fitness: flexibility, strength and balance. It is hypothesised that participants who are randomised to the exercise DVD condition will demonstrate improvements in physical function compared with participants assigned to the attentional control condition. Data analysis will include a 2 (condition)×2 (time) mixed factor analysis of variance (ANOVA) that follows intent-to-treat principles, as well as an examination of effect sizes. Participants will take part in qualitative interviews about perspectives on physical activity and programme participation.

Ethics and dissemination

The study protocol was approved by a university institutional review board and registered with a federal database. Participants will be asked to read and sign a detailed informed consent document and will be required to provide a physician's approval to participate in the study. The exercise DVDs include an overview of safety-related concerns and recommendations relative to exercise participation, as well as detailed instructions highlighting the proper execution of each exercise presented on screen. Following completion of this trial, data will be immediately analysed and results will be presented at scientific meetings and published in scholarly journals.

Trial registration number

Clinical TrialsNCT01993095.
Protocol investigating the clinical utility of an objective measure of activity and attention (QbTest) on diagnostic and treatment decision-making in children and young people with ADHD—‘AssessingQbTestUtility inADHD’ (AQUA): a randomised controlled trial
Authors: Hall Charlotte L , Walker Gemma M , Valentine Althea Z , Guo Boliang , Kaylor-Hughes Catherine , James Marilyn , Daley David , Sayal Kapil , Hollis Chris
Published: December 2014

Introduction

The National Institute for Health and Care Excellence (NICE) guidelines for attention deficit/hyperactivity disorder (ADHD) state that young people need to have access to the best evidence-based care to improve outcome. The current ‘gold standard’ ADHD diagnostic assessment combines clinical observation with subjective parent, teacher and self-reports. In routine practice, reports from multiple informants may be unavailable or contradictory, leading to diagnostic uncertainty and delay. The addition of objective tests of attention and activity may help reduce diagnostic uncertainty and delays in initiating treatment leading to improved outcomes. This trial investigates whether providing clinicians with an objective report of levels of attention, impulsivity and activity can lead to an earlier, and more accurate, clinical diagnosis and improved patient outcome.

Methods and analysis

This multisite randomised controlled trial will recruit young people (aged 6–17 years old) who have been referred for an ADHD diagnostic assessment at Child and Adolescent Mental Health Services (CAMHS) and Community Paediatric clinics across England. Routine clinical assessment will be augmented by the QbTest, incorporating a continuous performance test (CPT) and infrared motion tracking of activity. The participant will be randomised into one of two study arms: QbOpen (clinician has immediate access to a QbTest report): QbBlind (report is withheld until the study end). Primary outcomes are time to diagnosis and diagnostic accuracy. Secondary outcomes include clinician's diagnostic confidence and routine clinical outcome measures. Cost-effective analysis will be conducted, alongside a qualitative assessment of the feasibility and acceptability of incorporating QbTest in routine practice.

Ethics and dissemination

The findings from the study will inform commissioners, clinicians and managers about the feasibility, acceptability, clinical utility and cost-effectiveness of incorporating QbTest into routine diagnostic assessment of young people with ADHD. The results will be submitted for publication in peer-reviewed journals. The study has received ethical approval.

Trial registration number

NCT02209116.
Over-the-head two-thumb encircling technique as an alternative to the two-finger technique in the in-hospital infant cardiac arrest setting: a randomised crossover simulation study
Authors: Jo Choong Hyun , Jung Hwan Suk , Cho Gyu Chong , Oh You Jang
Published: November 2014

Objective

To determine if the over-the-head two-thumb encircling technique (OTTT) provides better quality cardiopulmonary resuscitation (CPR) than the conventional two-finger technique (TFT) when performed by a lone rescuer in an in-hospital infant cardiac arrest setting.

Methods

This prospective, randomised crossover design study recruited 50 nurses who voluntarily performed lone rescuer infant CPR for 2 min on a manikin. Participants who performed OTTT stood at the head of the manikin to compress the chest and provide bag–valve mask ventilations, whereas those who performed TFT stood by the side of the manikin to compress the chest and provide pocket–mask ventilations. Mean hands-off time, mean compression depths and rates, proportion of effective compressions and complete recoil, and fatigue score changes were assessed during the test, and a survey on the ease of use of the techniques was conducted after the test.

Results

Hands-off time, total ventilation volume and number of ventilations were not significantly different between the two techniques. OTTT resulted in greater depth of compressions (p<0.001), greater proportion of effective compressions (p<0.001), smaller proportion of complete recoil (p=0.001), and smaller fatigue score change (p=0.003) than TFT. In addition, subjects reported that compression, ventilation and changing compression to ventilation were easier using OTTT than TFT.

Conclusions

OTTT performed by a lone rescuer in an in-hospital infant cardiac arrest setting resulted in greater compression depth, with no increase in hands-off time, compared with TFT. OTTT may therefore be a suitable alternative to TFT in the in-hospital infant cardiac arrest setting.
Predictors of emergency service use in adolescents and adults with autism spectrum disorder living with family
Authors: Lunsky Yona , Paquette-Smith Melissa , Weiss Jonathan A , Lee Jacques
Published: November 2014

Introduction

The use of emergency services among adolescents and adults with autism spectrum disorder (ASD) transitioning into adult health services has not been well described.

Objectives

To describe emergency service use including emergency departments (EDs), paramedics, and police involvement among adolescents and adults with ASD and to examine predictors of using emergency services.

Methods

Caregivers of 396 adolescents and adults with ASD were recruited through autism advocacy agencies and support programmes in Ontario to complete a survey about their child's health service use. Surveys were completed online, by mail and over the phone between December 2010 and October 2012. Parents were asked to describe their child's emergency service use and provide information about potential predictive factors including predisposing, enabling and clinical need variables.

Results

According to parents, 13% of their children with ASD used at least one emergency service in a 2-month period. Sedation or restraints were used 23% of the time. A combination of need and enabling variables predicted emergency service use with previous ED use in the last year (OR 3.4, 95% CI 1.7 to 6.8), a history of hurting others (OR 2.3, 95% 1.2 CI to 4.7) and having no structured daytime activities (OR 3.2, 95% CI 1.4 to 7.0) being the strongest multivariate predictors in the model.

Conclusions

Patients with ASD and their families are likely to engage with paramedics or police or visit the ED. Further education and support to families and emergency clinicians are needed to improve and, when possible, prevent such occurrences.
Did Chile’s traffic law reform push police enforcement? Understanding Chile’s traffic fatalities and injuries reduction
Authors: Nazif-Munoz José Ignacio , Quesnel-Vallée Amélie , van den Berg Axel
Published: November 2014

Background

The objective of the current study is to determine to what extent the reduction of Chile’s traffic fatalities and injuries during 2000–2012 was related to the police traffic enforcement increment registered after the introduction of its 2005 traffic law reform.

Methods

A unique dataset with assembled information from public institutions and analyses based on ordinary least square and robust random effects models was carried out. Dependent variables were traffic fatality and severe injury rates per population and vehicle fleet. Independent variables were: (1) presence of new national traffic law; (2) police officers per population; (3) number of traffic tickets per police officer; and (4) interaction effect of number of traffic tickets per police officer with traffic law reform. Oil prices, alcohol consumption, proportion of male population 15–24 years old, unemployment, road infrastructure investment, years’ effects and regions’ effects represented control variables.

Results

Empirical estimates from instrumental variables suggest that the enactment of the traffic law reform in interaction with number of traffic tickets per police officer is significantly associated with a decrease of 8% in traffic fatalities and 7% in severe injuries. Piecewise regression model results for the 2007–2012 period suggest that police traffic enforcement reduced traffic fatalities by 59% and severe injuries by 37%.

Conclusions

Findings suggest that traffic law reforms in order to have an effect on both traffic fatality and injury rates reduction require changes in police enforcement practices. Last, this case also illustrates how the diffusion of successful road safety practices globally promoted by WHO and World Bank can be an important influence for enhancing national road safety practices.
Where art and science meet
Authors: Holden Ann
Published: December 2014

Ann Holden had to give up veterinary practice for medical reasons, and is now studying for membership of the Medical Artists' Association of Great Britain
10‐minute chat
Authors: Evans Mark
Published: December 2014

Mark Evans is probably best known as the presenter of Channel 4's Inside Nature's Giants. His 25‐year career has followed an unusual path; this, he says, is partly due to his short attention span, which meant he got side‐tracked from a career in practice. A common thread is his fascination with how things work and ‘an addictive need to fix things when they go wrong’.
Ten‐minute chat
Authors: Stacey Huw
Published: December 2014

Huw Stacey is commercial manager at Companion Care Services, which provides business services and support to the 94 surgeries of the Companion Care group.
New graduate's diary
Authors: Hall Jen
Published: December 2014

Jen Hall is busy organising practice meetings for farmers and stockmen, alongside meeting a demand for ongoing TB tests as farmers hope and prepare for better weather.
New graduate's diary
Authors: Hall Jen
Published: December 2014

It is almost a year to the day since Jen Hall graduated from Nottingham – one of the first group of vets to do so. Here, she looks back on her first year in practice and offers some thoughts on PDP.
Enjoying a diverse career
Authors: Barabas Stephen
Published: December 2014

Stephen Barabas always dreamed of being a vet; he had no ‘plan B’. Since qualifying, he has worked in practice, was a front line vet during the FMD epidemic in 2001, and then moved into industry. He recently set up a company to help vets develop their own websites
Veterinary forensics: more than ‘animal CSI’
Authors: Bailey David
Published: December 2014

Veterinary forensics is a new and emerging field of veterinary medicine. David Bailey, who recently developed a postgraduate training programme in the subject, outlines what the work involves
New graduate's diary
Authors: Hall Jennifer
Published: December 2014

Jennifer Hall discovers that dealing with the effects of bovine TB on farmers is very different from learning about the disease at vet school.
A career in government service and in international consultancy
Authors: Corrigan Philip
Published: December 2014

In 1972, Philip Corrigan planned to leave Ireland to go to Australia for a year, in order to satisfy his wanderlust. He never returned to live there, and has since worked all over the world
Clarifying specialist status
Authors: Andrews Freda
Published: December 2014

Clarifying the structure of specialisation is the task of a working party set up by the RCVS. Its recommendations, which have quality assurance at their heart, are now available for comment, explains Freda Andrews, RCVS head of education
Learning to teach – teaching to learn
Authors: Davies Faye
Published: December 2014

A Masters in Veterinary Education and other courses offered by the Royal Veterinary College (RVC) aim to develop individuals as professional veterinary and paraveterinary educators. RVC course administrator Faye Davies explains how the programmes can be followed via distance learning or face‐to‐face
Inhibitory effects of kaempferol on the invasion of human breast carcinoma cells by downregulating the expression and activity of matrix metalloproteinase-9
Authors: Li Chenglin , Zhao Yuanwei , Yang Dan , Yu Yanyan , Guo Hao , Zhao Ziming , Zhang Bei , Yin Xiaoxing
Published: December 2014

Matrix metalloproteinases (MMPs) have been regarded as major critical molecules assisting tumor cells during metastasis, for excessive ECM (ECM) degradation, and cancer cell invasion. In the present study, in vitro and in vivo assays were employed to examine the inhibitory effects of kaempferol, a natural polyphenol of flavonoid family, on tumor metastasis. Data showed that kaempferol could inhibit adhesion, migration, and invasion of MDA-MB-231 human breast carcinoma cells. Moreover, kaempferol led to the reduced activity and expression of MMP-2 and MMP-9, which were detected by gelatin zymography, real-time PCR, and western blot analysis, respectively. Further elucidation of the mechanism revealed that kaempferol treatment inhibited the activation of transcription factor activator protein-1 (AP-1) and MAPK signaling pathway. Moreover, kaempferol repressed phorbol-12-myristate-13-acetate (PMA)-induced MMP-9 expression and activity through suppressing the translocation of protein kinase Cδ (PKCδ) and MAPK signaling pathway. Our results also indicated that kaempferol could block the lung metastasis of B16F10 murine melanoma cells as well as the expression of MMP-9 in vivo. Taken together, these results demonstrated that kaempferol could inhibit cancer cell invasion through blocking the PKCδ/MAPK/AP-1 cascade and subsequent MMP-9 expression and its activity. Therefore, kaempferol might act as a therapeutic potential candidate for cancer metastasis.
Genetic structure of the introduced heaven tree (Ailanthus altissima) in Japan: evidence for two distinct origins with limited admixture
Authors: Kurokochi Hiroyuki , Saito Yoko , Ide Yuji
Published: December 2014

The heaven tree, Ailanthus altissima (Mill.) Swingle, was intentionally introduced from China to many temperate areas globally, where it has become successfully established. Here, we investigated the patterns of genetic differentiation between introduced Japanese A. altissima populations using both plastid and nuclear microsatellite markers. Three hundred and eighty-eight trees were sampled from six planted and 12 naturalized populations. Two distinct chloroplastic haplotypes were observed, which allowed us to separate two groups of trees, H1 and H3, containing 128 and 260 trees, respectively. Nine nuclear genetic microsatellites revealed 17.7 alleles per locus on average. These data did not indicate significant isolation-by-distance. Analysis of molecular variance showed the absence of genetic differentiation between the planted and naturalized populations. In contrast, the two groups defined according to the chloroplastic haplotypes (H1 and H3) were differentiated. STRUCTURE analysis showed that, within each haplotype group, most trees were strictly assigned to one cluster, with the exception of a few (ca. 30) trees. Our results indicate that (1) geographical genetic structure was weak, with high genetic variation among populations; (2) a congruent signal was revealed by chloroplastic and nuclear markers, indicating two distinct provenances; and (3) admixture between the two lineages has occurred, but remains limited. Several other invasive plant species have already been reported to exhibit similar trends; hence, future management of A. altissima might be required in Japan.
Utilizing ion mobility and tandem mass spectrometry to evaluate the structure and behaviour of multimeric cyclodextrin complexes
Authors: Berland Kevin , Renaud Justin B. , Mayer Paul M.
Published: December 2014

Characterizing noncovalent complexes of molecular dimers and higher complexes using tandem mass spectrometry (MS/MS) can be hindered due to spectral overlap in both the MS and the MS/MS. We investigated the structures and dissociation energetics of multimeric β-cyclodextrin (β-CD) complexes alone or with substrates using combinations of ion mobility spectrometry (IMS), MS/MS, and Rice–Ramsperger–Kassel–Marcus (RRKM) unimolecular rate modelling. The doubly charged β-CD dimers ([(β-CD)2 – 2H+]2−) dissociate to two [β-CD – H+]− ions with the same m/z. IMS was used to separate source generated [(β-CD)2 – 2H+]2− from [β-CD – H+]− and the extent of [(β-CD)2 – 2H+]2− dissociation versus collision energy was determined by modelling changes in the ion’s isotopic profile. The RRKM derived critical energy (E0) for dissociation of [(β-CD)2 – H+]− and [(β-CD)2 – 2H+]2− were 1.85 ± 0.11 eV and 1.79 ± 0.09 eV, respectively, corresponding to a slight decrease in complex stability due to increased charge–charge repulsion in the dianion. This approach was extended to include dimeric complexes complexed to 4,4′-(propane-1,3-diyl) dibenzoic acid (PDDA) and ibuprofen (Ibu).
The su(1,1)-like intensity-dependent Rabi model: A perturbative analysis of weak and strong-coupling regimes
Authors: Penna Vittorio , Raffa Francesco A.
Published: December 2014

We present a perturbative analysis of a Rabi model where the coupling between the quantized single-mode electromagnetic field and the two-level atom depends on the field intensity. Upon modeling the matter–radiation coupling through the Holstein–Primakoff realization of algebra su(1,1), we evaluate first- and second-order eigenenergies and eigenstates both in the weak-coupling regime (atom transition frequency smaller than the coupling strength) and in the strong-coupling regime. In the first case, among various effects, we observe a quadratic dependence on the photon number of energy eigenvalues and the possible formation of level doublets. In the strong-coupling case, the perturbative analysis becomes considerably complex due to the su(1,1)-valued form of the unperturbed Hamiltonian. The critical condition for the transition to an almost continuous spectrum is found in terms of the model parameters.
GPUfs
Authors: Silberstein Mark , Ford Bryan , Witchel Emmett
Published: December 2014

The GPUfs file system layer for GPU software makes core operating system abstractions available to GPU code.
Intelligent living
Authors: Mone Gregory
Published: December 2014

After years of false starts, the smart home is gaining momentum.
Port squatting
Authors: Neville-Neil George V.
Published: December 2014

Do not irk your local sysadmin.
Learning your limit
Authors: Rogers Timothy G. , O'Connor Mike , Aamodt Tor M.
Published: December 2014

The gap between processor and memory performance has become a focal point for microprocessor research and development over the past three decades. Modern architectures use two orthogonal approaches to help alleviate this issue: (1) Almost every microprocessor includes some form of on-chip storage, usually in the form of caches, to decrease memory latency and make more effective use of limited memory bandwidth. (2) Massively multithreaded architectures, such as graphics processing units (GPUs), attempt to hide the high latency to memory by rapidly switching between many threads directly in hardware. This paper explores the intersection of these two techniques. We study the effect of accelerating highly parallel workloads with significant locality on a massively multithreaded GPU. We observe that the memory access stream seen by on-chip caches is the direct result of decisions made by the hardware thread scheduler. Our work proposes a hardware scheduling technique that reacts to feedback from the memory system to create a more cache-friendly access stream. We evaluate our technique using simulations and show a significant performance improvement over previously proposed scheduling mechanisms. We demonstrate the effectiveness of scheduling as a cache management technique by comparing cache hit rate using our scheduler and an LRU replacement policy against other scheduling techniques using an optimal cache replacement policy.
Q&A: From Esterel to HipHop
Authors: Mone Gregory
Published: December 2014

This year's CNRS Gold Medal recipient, Gérard Berry, discusses his roots in computer science, why computers are stupid, and how he has helped to simplify programming.
Settable and non-interfering signal functions for FRP
Authors: Winograd-Cort Daniel , Hudak Paul
Published: December 2014

Functional Reactive Programming
(FRP) provides a method for programming continuous, reactive systems by utilizing
signal functions
that, abstractly, transform continuous input signals into continuous output signals. These signals may also be
streams of events
, and indeed, by allowing signal functions themselves to be the values carried by these events (in essence, signals of signal functions), one can conveniently make discrete changes in program behavior by "switching" into and out of these signal functions. This higher-order notion of switching is common among many FRP systems, in particular those based on arrows, such as Yampa.

Although convenient, the power of switching is often an overkill and can pose problems for certain types of program optimization (such as
causal commutative arrows
[14]), as it causes the structure of the program to change dynamically at run-time. Without a notion of just-in-time compilation or related idea, which itself is beset with problems, such optimizations are not possible at compile time.

This paper introduces two new ideas that obviate, in a predominance of cases, the need for switching. The first is a
non-interference
law for arrows with choice that allows an arrowized FRP program to dynamically alter its own structure (within statically limited bounds) as well as abandon unused streams. The other idea is a notion of a
settable signal function
that allows a signal function to capture its present state and later be restarted from some previous state. With these two features, canonical uses of higher-order switchers can be replaced with a suitable first-order design, thus enabling a broader range of static optimizations.
Lem
Authors: Mulligan Dominic P. , Owens Scott , Gray Kathryn E. , Ridge Tom , Sewell Peter
Published: December 2014

Recent years have seen remarkable successes in
rigorous engineering
: using mathematically rigorous semantic models (not just idealised calculi) of real-world processors, programming languages, protocols, and security mechanisms, for testing, proof, analysis, and design. Building these models is challenging, requiring experimentation, dialogue with vendors or standards bodies, and validation; their scale adds engineering issues akin to those of programming to the task of writing clear and usable mathematics. But language and tool support for specification is lacking. Proof assistants can be used but bring their own difficulties, and a model produced in one, perhaps requiring many person-years effort and maintained over an extended period, cannot be used by those familiar with another.

We introduce Lem, a language for engineering
reusable
large-scale semantic models. The Lem design takes inspiration both from functional programming languages and from proof assistants, and Lem definitions are translatable into OCaml for testing, Coq, HOL4, and Isabelle/HOL for proof, and LaTeX and HTML for presentation. This requires a delicate balance of expressiveness, careful library design, and implementation of transformations - akin to compilation, but subject to the constraint of producing usable and human-readable code for each target. Lem's effectiveness is demonstrated by its use in practice.
Building embedded systems with embedded DSLs
Authors: Hickey Patrick C. , Pike Lee , Elliott Trevor , Bielman James , Launchbury John
Published: December 2014

We report on our experiences in synthesizing a fully-featured autopilot from embedded domain-specific languages (EDSLs) hosted in Haskell. The autopilot is approximately 50k lines of C code generated from 10k lines of EDSL code and includes control laws, mode logic, encrypted communications system, and device drivers. The autopilot was built in less than two engineer years. This is the story of how EDSLs provided the productivity and safety gains to do large-scale low-level embedded programming and lessons we learned in doing so.
Maximal sharing in the Lambda calculus with letrec
Authors: Grabmayer Clemens , Rochel Jan
Published: December 2014

Increasing sharing in programs is desirable to compactify the code, and to avoid duplication of reduction work at run-time, thereby speeding up execution. We show how a maximal degree of sharing can be obtained for programs expressed as terms in the lambda calculus with letrec. We introduce a notion of 'maximal compactness' for λ
letrec
-terms among all terms with the same infinite unfolding. Instead of defined purely syntactically, this notion is based on a graph semantics. λ
letrec
-terms are interpreted as first-order term graphs so that unfolding equivalence between terms is preserved and reflected through bisimilarity of the term graph interpretations. Compactness of the term graphs can then be compared via functional bisimulation.

We describe practical and efficient methods for the following two problems: transforming a λ
letrec
-term into a maximally compact form; and deciding whether two λ
letrec
-terms are unfolding-equivalent. The transformation of a λ
letrec
-terms
L
into maximally compact form
L
0
proceeds in three steps: (i) translate
L
into its term graph
G
= [[L]] ; (ii) compute the maximally shared form of
G
as its bisimulation collapse
G
0
; (iii) read back a λ
letrec
-term
L
0
from the term graph
G
0
with the property [[
L
0
]] =
G
0
. Then
L
0
represents a maximally shared term graph, and it has the same unfolding as
L
.

The procedure for deciding whether two given λ
letrec
-terms
L
1
and
L
2
are unfolding-equivalent computes their term graph interpretations [[
L
1
]] and [[
L
2
]], and checks whether these are bisimilar.

For illustration, we also provide a readily usable implementation.
A theory of gradual effect systems
Authors: Bañados Schwerter Felipe , Garcia Ronald , Tanter Éric
Published: December 2014

Effect systems have the potential to help software developers, but their practical adoption has been very limited. We conjecture that this limited adoption is due in part to the difficulty of transitioning from a system where effects are implicit and unrestricted to a system with a static effect discipline, which must settle for conservative checking in order to be decidable. To address this hindrance, we develop a theory of gradual effect checking, which makes it possible to incrementally annotate and statically check effects, while still rejecting statically inconsistent programs. We extend the generic type-and-effect framework of Marino and Millstein with a notion of unknown effects, which turns out to be significantly more subtle than unknown types in traditional gradual typing. We appeal to abstract interpretation to develop and validate the concepts of gradual effect checking. We also demonstrate how an effect system formulated in Marino and Millstein's framework can be automatically extended to support gradual checking.
Functional programming for dynamic and large data with self-adjusting computation
Authors: Chen Yan , Acar Umut A. , Tangwongsan Kanat
Published: December 2014

Combining type theory, language design, and empirical work, we present techniques for computing with large and dynamically changing datasets. Based on lambda calculus, our techniques are suitable for expressing a diverse set of algorithms on large datasets and, via self-adjusting computation, enable computations to respond automatically to changes in their data. To improve the scalability of self-adjusting computation, we present a type system for precise dependency tracking that minimizes the time and space for storing dependency metadata. The type system eliminates an important assumption of prior work that can lead to recording spurious dependencies. We present a type-directed translation algorithm that generates correct self-adjusting programs without relying on this assumption. We then show a probabilistic-chunking technique to further decrease space usage by controlling the fundamental space-time tradeoff in self-adjusting computation. We implement and evaluate these techniques, showing promising results on challenging benchmarks involving large graphs.
SeLINQ
Authors: Schoepe Daniel , Hedin Daniel , Sabelfeld Andrei
Published: December 2014

The root cause for
confidentiality
and
integrity
attacks against computing systems is insecure
information flow
. The complexity of modern systems poses a major challenge to secure
end-to-end
information flow, ensuring that the insecurity of a single component does not render the entire system insecure. While information flow in a variety of languages and settings has been thoroughly studied in isolation, the problem of tracking information across component boundaries has been largely out of reach of the work so far. This is unsatisfactory because tracking information across component boundaries is necessary for end-to-end security.

This paper proposes a framework for uniform tracking of information flow through both the application and the underlying database. Key enabler of the uniform treatment is recent work by Cheney et al., which studies database manipulation via an embedded language-integrated query language (with Microsoft's LINQ on the backend). Because both the host language and the embedded query languages are functional F#-like languages, we are able to leverage information-flow enforcement for functional languages to obtain information-flow control for databases "for free", synergize it with information-flow control for applications and thus guarantee security across application-database boundaries. We develop the formal results in the form of a security type system that includes a treatment of algebraic data types and pattern matching, and establish its soundness. On the practical side, we implement the framework and demonstrate its usefulness in a case study with a realistic movie rental database.
Krivine nets
Authors: Fredriksson Olle , Ghica Dan R.
Published: December 2014

We define a new approach to compilation to distributed architectures based on networks of abstract machines. Using it we can implement a generalised and fully transparent form of Remote Procedure Call that supports calling higher-order functions across node boundaries, without sending actual code. Our starting point is the classic Krivine machine, which implements reduction for untyped call-by-name PCF. We successively add the features that we need for distributed execution and show the correctness of each addition. Then we construct a two-level operational semantics, where the high level is a network of communicating machines, and the low level is given by local machine transitions. Using these networks, we arrive at our final system, the
Krivine Net
. We show that Krivine Nets give a correct distributed implementation of the Krivine machine, which preserves both termination and non-termination properties. All the technical results have been formalised and proved correct in Agda. We also implement a prototype compiler which we compare with previous distributing compilers based on Girard's Geometry of Interaction and on Game Semantics.
Practical and effective higher-order optimizations
Authors: Bergstrom Lars , Fluet Matthew , Le Matthew , Reppy John , Sandler Nora
Published: December 2014

Inlining is an optimization that replaces a call to a function with that function's body. This optimization not only reduces the overhead of a function call, but can expose additional optimization opportunities to the compiler, such as removing redundant operations or unused conditional branches. Another optimization, copy propagation, replaces a redundant copy of a still-live variable with the original. Copy propagation can reduce the total number of live variables, reducing register pressure and memory usage, and possibly eliminating redundant memory-to-memory copies. In practice, both of these optimizations are implemented in nearly every modern compiler.

These two optimizations are practical to implement and effective in first-order languages, but in languages with lexically-scoped first-class functions (aka, closures), these optimizations are not available to code programmed in a higher-order style. With higher-order functions, the analysis challenge has been that the environment at the call site must be the same as at the closure capture location, up to the free variables, or the meaning of the program may change. Olin Shivers' 1991 dissertation called this family of optimizations
superΒ
and he proposed one analysis technique, called
reflow
, to support these optimizations. Unfortunately, reflow has proven too expensive to implement in practice. Because these higher-order optimizations are not available in functional-language compilers, programmers studiously avoid uses of higher-order values that cannot be optimized (particularly in compiler benchmarks).

This paper provides the first practical and effective technique for
superΒ
(higher-order) inlining and copy propagation, which we call unchanged variable analysis. We show that this technique is practical by implementing it in the context of a real compiler for an ML-family language and showing that the required analyses have costs below 3% of the total compilation time. This technique's effectiveness is shown through a set of benchmarks and example programs, where this analysis exposes additional potential optimization sites.
A relational framework for higher-order shape analysis
Authors: Kaki Gowtham , Jagannathan Suresh
Published: December 2014

We propose the integration of a relational specification framework within a dependent type system capable of verifying complex invariants over the shapes of algebraic datatypes. Our approach is based on the observation that structural properties of such datatypes can often be naturally expressed as inductively-defined
relations
over the recursive structure evident in their definitions. By interpreting constructor applications (abstractly) in a relational domain, we can define expressive relational abstractions for a variety of complex data structures, whose structural and shape invariants can be automatically verified. Our specification language also allows for definitions of
parametric
relations for polymorphic data types that enable highly composable specifications and naturally generalizes to higher-order polymorphic functions.

We describe an algorithm that translates relational specifications into a decidable fragment of first-order logic that can be efficiently discharged by an SMT solver. We have implemented these ideas in a type checker called CATALYST that is incorporated within the MLton SML compiler. Experimental results and case studies indicate that our verification strategy is both practical and effective.
Romeo
Authors: Stansifer Paul , Wand Mitchell
Published: December 2014

Current languages for safely manipulating values with names only support term languages with simple binding syntax. As a result, no tools exist to safely manipulate code written in those languages for which name problems are the most challenging. We address this problem with Romeo, a language that respects α-equivalence on its values, and which has access to a rich specification language for binding, inspired by attribute grammars. Our work has the complex-binding support of David Herman's λ

m

, but is a full-fledged binding-safe language like Pure FreshML.
Behavioral software contracts
Authors: Findler Robert Bruce
Published: December 2014

Programmers embrace contracts. They can use the language they know and love to formulate logical assertions about the behavior of their programs. They can use the existing IDE infrastructure to log contracts, to test, to debug, and to profile their programs.

The keynote presents the challenges and rewards of supporting contracts in a modern, full-spectrum programming language. It covers technical challenges of contracts while demonstrating the non-technical motivation for contract system design choices and showing how contracts and contract research can serve practicing programmers.

The remainder of this article is a literature survey of contract research, with an emphasis on recent work about higher-order contracts and blame.
Race directed scheduling of concurrent programs
Authors: Eslamimehr Mahdi , Palsberg Jens
Published: December 2014

Detection of data races in Java programs remains a difficult problem. The best static techniques produce many false positives, and also the best dynamic techniques leave room for improvement. We present a new technique called race directed scheduling that for a given race candidate searches for an input and a schedule that lead to the race. The search iterates a combination of concolic execution and schedule improvement, and turns out to find useful inputs and schedules efficiently. We use an existing technique to produce a manageable number of race candidates. Our experiments on 23 Java programs found 72 real races that were missed by the best existing dynamic techniques. Among those 72 races, 31 races were found with schedules that have between 1 million and 108 million events, which suggests that they are rare and hard-to-find races.
A tool to analyze the performance of multithreaded programs on NUMA architectures
Authors: Liu Xu , Mellor-Crummey John
Published: December 2014

Almost all of today's microprocessors contain memory controllers and directly attach to memory. Modern multiprocessor systems support non-uniform memory access (NUMA): it is faster for a microprocessor to access memory that is directly attached than it is to access memory attached to another processor. Without careful distribution of computation and data, a multithreaded program running on such a system may have high average memory access latency. To use multiprocessor systems efficiently, programmers need performance tools to guide the design of NUMA-aware codes. To address this need, we enhanced the HPCToolkit performance tools to support measurement and analysis of performance problems on multiprocessor systems with multiple NUMA domains. With these extensions, HPCToolkit helps pinpoint, quantify, and analyze NUMA bottlenecks in executions of multithreaded programs. It computes derived metrics to assess the severity of bottlenecks, analyzes memory accesses, and provides a wealth of information to guide NUMA optimization, including information about how to distribute data to reduce access latency and minimize contention. This paper describes the design and implementation of our extensions to HPCToolkit. We demonstrate their utility by describing case studies in which we use these capabilities to diagnose NUMA bottlenecks in four multithreaded applications.
Parallelization hints via code skeletonization
Authors: Aguston Cfir , Ben Asher Yosi , Haber Gadi
Published: December 2014

Tools that provide optimization hints for program developers are facing severe obstacles and often unable to provide meaningful guidance on how to parallelize real--life applications. The main reason is due to the high code complexity and its large size when considering commercially valuable code. Such code is often rich with pointers, heavily nested conditional statements, nested while--based loops, function calls, etc. These constructs prevent existing compiler analysis from extracting the full parallelization potential. We propose a new paradigm to overcome this issue by automatically transforming the code into a much simpler skeleton-like form that is more conductive for auto-parallelization. We then apply existing tools of source--level automatic parallelization on the skeletonized code in order to expose possible parallelization patterns. The skeleton code, along with the parallelized version, are then provided to the programmer in the form of an IDE (Integrated Development Environment) recommendation.

The proposed skeletonization algorithm replaces pointers by integer indexes and C-struct references by references to multi-dimensional arrays. This is because automatic parallelizers cannot handle pointer expressions. For example, while(p != NULL){ p->val++; p=p->next; } will be skeletonized to the parallelizable for(Ip=0;Ip<N;Ip++){ Aval[Ip]++; } where Aval[] holds the embedding of the original list. It follows that the main goal of the skeletonization process is to embed pointer-based data structures into arrays. Though the skeletonized code is not semantically equivalent to the original code, it points out a possible parallelization pattern for this code segment and can be used as an effective parallelization hint to the programmer. We applied the method on several representative benchmarks from SPEC CPU 2000 and reached up to 80% performance gain after several sequential code segments had been manually parallelized based on the parallelization patterns of the generated skeletons. In a different set of experiments we tried to estimate the potential of skeletonization for a larger set of programs in SPEC 2000 and obtained an estimation of 27% additional loops that can be parallelized/vectorized due to skeletonization.