bluuebunny/crossref_metadata_2025 huggingface dataset:
Diabetic retinopathy and the use of laser photocoagulation: is it cost-effective to treat early?
Authors: Mistry Hema , Auguste Peter , Lois Noemi , Waugh Norman
Published: September 2017

Background/aims

The aim of the study was to explore whether it would be cost-effective to apply panretinal photocoagulation (PRP) at the severe non-proliferative diabetic retinopathy (NPDR) (early treatment) stage, compared with waiting until high-risk proliferative diabetic retinopathy (HR-PDR) characteristics (deferred treatment) developed.

Methods

A Markov model with a 30-year time horizon was developed, in which patients presenting with moderate NPDR could progress through all stages of DR (severe NPDR>early PDR>HR-PDR>severe PDR) to severe vision loss and blindness (and to death). A National Health Service and personal social services perspective was adopted. Transition probabilities were mainly derived from the Early Treatment Diabetic Retinopathy Study. Health state utilities, costs and complications were based on information from the literature, supplemented by expert opinion. Costs and outcomes were discounted at 3.5%. Both deterministic and probabilistic sensitivity analyses were conducted.

Results

Administering PRP at the severe NPDR stage could be more effective and less costly than waiting until HR-PDR developed. Sensitivity analyses gave similar results, with early treatment continuing to dominate deferred treatment. The probabilistic sensitivity analysis suggests that at willingness-to-pay threshold of £20–£30 000 per quality-adjusted life year, the probability of early treatment being cost-effective is 60%.

Conclusion

PRP administered at the severe NPDR stage is likely to be cost-effective compared with delaying photocoagulation until HR-PDR develops. However, given the limitations of the evidence, these results need to be interpreted with caution. A trial of early versus deferred laser therapy is needed to provide better data based on modern treatments.
PP15 Consent as an ethical consideration in the conduct of prehospital ambulance randomised controlled clinical trials: a systematic review
Authors: Armstrong Stephanie , Langlois Adele , Laparidou Despina , Dixon Mark , Appleton Jason P , Bath Philip M , Snooks Helen , Siriwardena A Niroshan
Published: September 2017

Background

Clinical trials in the ambulance setting are essential for providing the basis for evidence based healthcare in the prehospital environment. As the number and complexity of ambulance trials increases the ethical issues involved in such trials. We sought to understand the main ethical considerations when conducting clinical trials in the prehospital ambulance based setting.

Methods

We conducted a systematic review of ethical issues considered in randomised controlled trials in ambulance settings. A search of eight databases identified ethical issues discussed in published studies involving recruitment of ambulance service users. Four independent authors undertook abstract and full-text reviews to determine eligibility and then extracted relevant data. The data extraction concentrated on ethical considerations, with any discussion of ethics being included for further analysis. The resultant data were combined to form a narrative synthesis.

Results

In all, 56 papers were identified as meeting the inclusion criteria. Issues relating to consent were the most significant theme identified. Several consent models were used ranging from informed consent to exception from informed consent (also termed waiver of consent). Type of consent differed depending on the clinical condition or the intervention being studied. The country in which the research took place did not appear to influence the type of consent, apart from the USA where exception from informed consent appeared to be most commonly used. Many studies cited international guidelines as informing their choice of consent model and diverse and sometimes confused terms were used to describe these models.

Conclusions

Consent was the main ethical consideration in published ambulance based research. A wide range of terms was used to describe consent and terms were sometimes confused or used inconsistently. This suggests that standardisation of consent models and the terminology used to describe them may be helpful for researchers, ethics committees and research participants.
PP23 A comparative evaluation of 999 call-to-needle time of patients presenting with red flag sepsis treated with antibiotics by paramedics and emergency department staff
Authors: Payne Tanya , Chippendale Jonathon , Lloyd Adele
Published: September 2017

Background

National Institute for Health and Care Excellence guidelines on the recognition, diagnosis and early management of sepsis suggest that in all cases of high risk (or ‘red flag’) sepsis a broad spectrum antibiotic is given without delay and within one hour. For patients identified pre-hospital, GP’s and ambulance services are advised to have mechanisms in place that will allow them to give antibiotics but only where the transfer time is greater than one hour.

Whilst one hour is considered the gold standard timeframe in which to receive antibiotics, the 999 call dispatch process is often overlooked and there are no studies to date that examine the 999 call-to-needle time for sepsis patients.

The aim of this evaluation was to explore the difference between call-to-needle times of patients who present with ‘red flag’ sepsis receiving antibiotic therapy by a paramedic pre hospital versus Emergency Department (ED) staff.

Method

Data collected from a feasibility evaluation was used to determine the call-to-needle time of a broad spectrum antibiotic given by a trained paramedic prior to arrival at ED. A random sample of patients arriving in ED by ambulance with high risk (or ‘red flag’) sepsis during the same 6 month period was identified with the call-to-needle time collected retrospectively. A Mann-Whitney U test was performed using SPSS version 22 to determine if there was any significant difference.

Results

Of the patients that were treated (n=140) the median call-to-needle time of patients treated by paramedics was 45:30 min (n=60), compared to a median call-to-needle time by ED staff of 113:30 min (n=80) (p<0.001).

Conclusion

Considering the call dispatch challenges that all ambulance services experience, patients with ‘red flag’ sepsis can be treated with an antibiotic within an hour of the 999 call and on average one hour earlier than patients who are treated by ED staff.
PP25 Using a linked health dataset to identify what happens to patients following prehospital care
Authors: Coster Joanne , O’Cathain Alicia , Crum Annabel , Jacques Richard , Nicholl Jon , Turner Janette
Published: September 2017

Background

UK prehospital services receive poor information about what happens to patients beyond the prehospital phase of care; this limits the opportunity to assess patient outcomes following non-conveyance. We aimed to identify what happens to patients after prehospital discharge, as part of two studies 1) to develop better ways of measuring prehospital quality and performance (Prehospital Outcomes for Evidence Based Evaluation, (PhOEBE)) and 2) to assess Variation in Ambulance Non-conveyance decisions (VAN).

Method

We developed a patient level dataset, linking ambulance call and clinical data to subsequent ED, hospital and mortality data. Data for 6 months of 2013 was provided by one ambulance service and linked to national datasets using NHS Digital’s data-linking service. We identified a sub-group of non-conveyed patients and identified recontacts (EMS, ED, hospital admission or death) within 3 days of the call. We traced 24% (2514/10634) of hear and treat calls and 84% (42,796/50894) of see and treat calls.

Results

Within our sample, 20.6% of see and treat calls had a recontact within 3 days, 6.3% (2694/42.796) were admitted to hospital and 0.3% (129/42796) died. Poor hear and treat linkage rates limited data reliability, therefore we conducted a sensitivity analysis using traced calls only and traced plus non-traced calls as the denominator. We found that hear and treat hospital admissions within 3 days range from 2.5%–10.5% and deaths within 3 days range from 0.06%–0.24%

We developed a new indicator to monitor the quality and safety of non-transport decisions “Proportion of calls left at home which result in hospital admission or death within 3 days”.

Conclusions

We linked multiple data sources to identify what happens to patients following prehospital care and identified low rates of hospital admission and death following non-conveyance. We developed a new non-conveyance indicator to assess safety and monitor non-conveyance rates over time.
PP27 Terms used to describe key symptoms in out-of-hospital cardiac arrest by people calling 999 emergency medical services: a qualitative analysis of call recordings to two uk ambulance services
Authors: Gibson Josephine ME , Jones Stephanie P , Hurley Margaret , Auton Mal , Leathley Michael J , Sutton Christopher J , Bangee Munirah , Benedetto Valerio , Chesworth Brigit , Miller Colette , O’Shea Dawn , Quinn Tom , Mackway-Jones Kevin C , Curran Andy , Niroshan Siriwardena A , Davis David , Price Chris , Dewitt David , Barron Tracey , Fox Peter , Watkins Caroline L
Published: September 2017

Background

Cardiac arrest outside hospital is a catastrophic medical emergency experienced by an estimated 60 000 people a year in the UK. The speed and accuracy with which cardiac arrest outside hospital is recognised by 999 call handlers is fundamental to improving the chance of survival, but is extremely challenging. We aimed to identify how cardiac arrest is actually described by callers during dialogues with 999 call handlers.

Methods

Data was obtained from two acute NHS trusts and their two local ambulance trusts for all cases of suspected or actual out-of-hospital cardiac arrest (OHCA) or imminent medically witnessed cardiac arrest (MWCA) which led to transfer to one of the study hospitals, for a one year period (1/7/2013–30/6/2014). The 999 call recordings were listened to in full; words or phrases used by callers to describe clinical signs and symptoms were identified and clustered into key indicator symptoms using a thematic approach.

Findings

429 cases of cardiac arrest were identified, of which 246 (57.3%) were dispatched using a ‘cardiac arrest’ code. 6 callers (1.4%) used the term ‘cardiac arrest’ or a synonym. Key indicator symptoms reported most frequently were unconsciousness (64.8%), ineffective breathing (61.9%), and absent breathing (48.8%). Descriptors of conscious level included diverse colloquialisms and terms relating to reduced or fluctuating level of consciousness (17.2%). Descriptors of ineffective breathing included diverse terms relating to slow, fast, irregular, agonal, dyspnoea, and shallow breathing, plus nonspecific terms (e.g. ‘breathing’s funny); and ‘don’t know’ statements.

Conclusion

Callers’ descriptors of key symptoms of OHCA are varied and include many colloquialisms. Call handler training should include awareness of likely descriptions, particularly of ineffective breathing, which may be more commonly reported than absent breathing.
BET 2: Treatment of frostbite with iloprost
Authors: Kaller Margo
Published: September 2017

A short cut review was carried out to establish whether an infusion of iloprost can be used to treat frostbite to reduce the risk of needing an amputation. Three studies were directly relevant to the question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of these papers are tabulated. The clinical bottom line is that iloprost may reduce the risk of amputation after frostbite.
Reactive oxygen species signalling in the diabetic heart: emerging prospect for therapeutic targeting
Authors: Wilson Adam J , Gill Eleanor K , Abudalo Rawan A , Edgar Kevin S , Watson Chris J , Grieve David J
Published: September 2017

Despite being first described 45 years ago, the existence of a distinct diabetic cardiomyopathy remains controversial. Nonetheless, it is widely accepted that the diabetic heart undergoes characteristic structural and functional changes in the absence of ischaemia and hypertension, which are independently linked to heart failure progression and are likely to underlie enhanced susceptibility to stress. A prominent feature is marked collagen accumulation linked with inflammation and extensive extracellular matrix changes, which appears to be the main factor underlying cardiac stiffness and subclinical diastolic dysfunction, estimated to occur in as many as 75% of optimally controlled diabetics. Whether this characteristic remodelling phenotype is primarily driven by microvascular dysfunction or alterations in cardiomyocyte metabolism remains unclear. Although hyperglycaemia regulates multiple pathways in the diabetic heart, increased reactive oxygen species (ROS) generation is thought to represent a central mechanism underlying associated adverse remodelling. Indeed, experimental and clinical diabetes are linked with oxidative stress which plays a key role in cardiomyopathy, while key processes underlying diabetic cardiac remodelling, such as inflammation, angiogenesis, cardiomyocyte hypertrophy and apoptosis, fibrosis and contractile dysfunction, are redox sensitive. This review will explore the relative contributions of the major ROS sources (dysfunctional nitric oxide synthase, mitochondria, xanthine oxidase, nicotinamide adenine dinucleotide phosphate oxidases) in the diabetic heart and the potential for therapeutic targeting of ROS signalling using novel pharmacological and non-pharmacological approaches to modify specific aspects of the remodelling phenotype in order to prevent and/or delay heart failure development and progression.
Impact of QTc formulae in the prevalence of short corrected QT interval and impact on probability and diagnosis of short QT syndrome
Authors: Providência Rui , Karim Nabeela , Srinivasan Neil , Honarbakhsh Shohreh , Vidigal Ferreira Maria João , Gonçalves Lino , Marijon Eloi , Lambiase Pier D
Published: September 2017

Objective

To assess the prevalence of short corrected QT (QTc) intervals and its impact on short QT syndrome (SQTS) diagnosis using different QT correction formulae.

Methods

Observational study. The prevalence of short QTc intervals was estimated using four different QT correction formulae in 14 662 young adults from the ‘Sudden Cardiac Death Screening of Risk FactOrS’ (SCD-SOS) cohort. Then, using data from this cohort and the pooled-cohort analysed by Gollob et al, comprising 61 patients with SQTS, we assessed the impact of the different QTc correction formulae on SQTS probability and diagnosis based on the Expert Consensus recommendations (QTc ≤330 ms or QTc 330–360 ms+1 additional risk feature).

Results

The prevalence of individuals with a QTc ≤330 and ≤320 ms in the SCD-SOS cohort was extremely low (≤0.07% and≤0.02%, respectively), and these were more frequently identified by the Framingham correction. The different QTc correction formulae led to a shift in SQTS probability in 5%–10% of individuals in both the SCD-SOS and Gollob cohort). Intermediate probability individuals were rare (<0.1%), and no high-SQTS probability individuals were identified in the SCD-SOS cohort. Based on Consensus criteria, instead of 12 (0.08%) individuals being diagnosed with SQTS using the Bazett equation, a different number of individuals would meet diagnostic criteria with the other formulae: 11 (0.08%) using Fridericia, 9 (0.06%) with Hodges and 16 (0.11%) using the Framingham equation.

Conclusion

Prevalence of SQTS in the apparently healthy adult population is low. Applying different QTc correction formulae leads to significant reclassification of SQTS probability and their impact on predicting outcomes should be assessed.
Deep learning guided stroke management: a review of clinical applications
Authors: Feng Rui , Badgeley Marcus , Mocco J , Oermann Eric K
Published: September 2017

Stroke is a leading cause of long-term disability, and outcome is directly related to timely intervention. Not all patients benefit from rapid intervention, however. Thus a significant amount of attention has been paid to using neuroimaging to assess potential benefit by identifying areas of ischemia that have not yet experienced cellular death. The perfusion–diffusion mismatch, is used as a simple metric for potential benefit with timely intervention, yet penumbral patterns provide an inaccurate predictor of clinical outcome. Machine learning research in the form of deep learning (artificial intelligence) techniques using deep neural networks (DNNs) excel at working with complex inputs. The key areas where deep learning may be imminently applied to stroke management are image segmentation, automated featurization (radiomics), and multimodal prognostication. The application of convolutional neural networks, the family of DNN architectures designed to work with images, to stroke imaging data is a perfect match between a mature deep learning technique and a data type that is naturally suited to benefit from deep learning’s strengths. These powerful tools have opened up exciting opportunities for data-driven stroke management for acute intervention and for guiding prognosis. Deep learning techniques are useful for the speed and power of results they can deliver and will become an increasingly standard tool in the modern stroke specialist’s arsenal for delivering personalized medicine to patients with ischemic stroke.
Achieving comprehensive disease control in patients with early and established rheumatoid arthritis treated with adalimumab plus methotrexate versus methotrexate alone
Authors: Keystone Edward C , Breedveld Ferdinand C , Heijde Désirée van der , van Vollenhoven Ronald F , Emery Paul , Smolen Josef S , Sainsbury Iain , Florentinus Stefan , Kupper Hartmut , Chen Kun , Kavanaugh Arthur
Published: September 2017

Objective

To evaluate the achievement of comprehensive disease control (CDC) following 1 year of treatment with adalimumab+methotrexate versus methotrexate alone and whether early achievement of remission (at week 24 or 26) is associated with CDC at week 52 in patients with either early or established rheumatoid arthritis (RA).

Methods

Post hoc analyses were conducted in three clinical studies assessing treatment with adalimumab+methotrexate: DE019 (NCT00195702) enrolled patients with established RA who were methotrexate inadequate responders; OPTIMA (NCT00420927) and PREMIER (NCT00195663) enrolled methotrexate-naive patients with early RA. In OPTIMA, patients not achieving stable low disease activity at weeks 22 and 26 in the placebo+methotrexate group could receive open-label adalimumab+methotrexate for 52 weeks (Rescue ADA arm). CDC was defined as the simultaneous achievement of clinical remission (DAS28(CRP)<2.6), normal function (HAQ-DI<0.5) and absence of radiographic progression (ΔmTSS≤0.5).

Results

Regardless of disease duration, significantly more patients receiving adalimumab+methotrexate achieved CDC compared with methotrexate alone. In the adalimumab+methotrexate group, a numerically greater proportion of patients with early RA (~25%) versus established RA (14%) achieved CDC at 1 year; achievement of CDC was notably greater among patients who met criteria for remission at week 24 or 26 (~50% of patients with early RA and 39% with established RA).

Conclusion

Treatment with adalimumab+methotrexate increases the likelihood of achieving CDC in patients with either early or established RA. Clinical remission at week 24 or 26 is associated with achievement of CDC at week 52.

Trial registration number

DE019 (NCT00195702), OPTIMA (NCT00420927), PREMIER (NCT00195663); Post-results.
Pharmacokinetics of marbofloxacin administered via intravenous regional limb perfusion in dairy cows: evaluation of two different tourniquets
Authors: Celani Gianluca , Tulini Serena Maria Rita , Montesano Camilla , Zezza Daniela , Sergi Manuel , Varasano Vincenzo , Mortellaro Carlo Maria , Compagnone Dario , Amorena Michele , Petrizzi Lucio
Published: September 2017

Objectives

This study evaluated synovial and systemic plasma pharmacokinetic variables of marbofloxacin after a single intravenous regional limb perfusion (IVRLP) performed using two different tourniquets in clinically healthy, standing, non‐sedated dairy cows. The authors hypothesised that the type of tourniquet used for IVRLP would influence the synovial fluid concentration of marbofloxacin in the perfused distal limb.

Design

The study had a randomised parallel‐group design.

Methods

Ten adult dairy cows were included. Unilateral hindlimb IVRLP through the dorsal common digital III vein was performed in two groups of five cows (group 1: wide rubber tourniquet; group 2: manual pneumatic tourniquet) using 0.67 mg/kg of marbofloxacin. The tourniquet was applied proximal to the tarsus and maintained for 30 minutes. Samples of jugular blood and synovial fluid from the tibiotarsal joints of the perfused limb were obtained before and at intervals after IVRLP. All samples were analysed for drug concentrations using liquid chromatography tandem mass spectrometry. Pharmacokinetic parameters were determined to establish the influence of tourniquet types. Differences were considered significant at P≤0.05.

Results

No adverse effects from the procedure or marbofloxacin were observed in any animal. Significant differences in synovial concentrations and pharmacokinetic parameters were measured. The mean ± sd areas under the concentration versus time curve from time 0 to 24 hours were 178.98±58.08 µg hour/ml for group 2 and 21.11±9.93 µg hour/ml for group 1. The mean ± sd maximum marbofloxacin concentrations were 75.50±10.19 µg/ml for group 2 and 6.35±1.47 µg/ml for group 1.

Conclusions

Performing IVRLP using the dorsal common digital III vein and a manual pneumatic tourniquet set at 300 mmHg above the tarsus in standing cows resulted in significantly higher marbofloxacin concentrations in the tibiotarsal joint compared with those with the wide rubber tourniquet.

Trial registration

Local ethical committee (number 41/2012/CEISA).
Factors related to work and life satisfaction of veterinary practitioners in Germany
Authors: Kersebohm Johanna C , Lorenz Timo , Becher Anne , Doherr Marcus G
Published: September 2017

Objectives

Veterinary practitioners’ working situation is both challenging and changing. They have higher levels of work‐related stress and suicide risk than the general population. The proportion of women is increasing, and in Germany especially women and employed veterinarians are reported to be less satisfied than comparable subgroups of the general population. In this study we identified key factors associated with work and life satisfaction among veterinary practitioners in Germany.

Design

Questionnaire‐based cross‐sectional survey.

Setting

All veterinary practitioners registered in Germany in 2016.

Participants

There were 2549 respondents, of whom 1930 met the inclusion criteria for further analysis. They had a median age of 37 and the majority of respondents were women (79.3 per cent). Almost two‐thirds (63.8 per cent) worked as employed veterinarian.

Primary outcomes

Importance of different job characteristics measured in 5‐point Likert items, work satisfaction measured on a 5‐point Likert item and life satisfaction measured in 11‐point Likert items.

Secondary outcomes

Facets such as satisfaction with leisure time, family life, health and standard of living, information on working conditions such as working time, income, as well as year of birth and other demographic data.

Results

A ‘good working atmosphere’ was the most relevant job characteristic for all veterinary practitioners. Work satisfaction of employed practitioners is closely linked to satisfaction with their colleagues. This link is less pronounced for self‐employed practitioners. A ‘reasonable salary’ was the second and ‘holidays and leisure time’ was the third most important job characteristics for employed practitioners. A ‘good working atmosphere’ and ‘family friendly arrangements’ were statistically significantly more important for women than for men, while a ‘reasonable salary’ was more important for men.

Conclusions

Our results indicate strong associations between levels of work satisfaction and various work‐related factors in subgroups of veterinary practitioners in Germany that reduce life satisfaction. The strength of some associations differs between men and women, as well as between self‐employed and employed veterinarians. Outgoing students should be better prepared for the challenging working conditions that they face in veterinary practice. Salary levels should be improved and the working conditions adapted to the respective subgroups in order to increase work and life satisfaction.
Ground-dwelling arthropod response to fire and clearcutting in jack pine: implications for ecosystem management
Authors: Venier L.A. , Work T.T. , Klimaszewski J. , Morris D.M. , Bowden J.J. , Kwiaton M.M. , Webster K. , Hazlett P.
Published: September 2017

We tested the response of species composition of three dominant litter-dwelling arthropod taxa (carabid beetles, spiders, and rove beetles) to wildfire and harvest. This study was conducted in north-central Ontario (47°42′N, 83°36′W) in jack pine (Pinus banksiana Lamb.) dominated stands in 2013 using pitfall trapping. Using 222 species (12 015 individuals), we compared the effects of disturbance using recently burned (3 years since fire) and clearcut sites (3 years since harvest; tree length, full tree, stump removal, and blading), as well as older, closed-canopy stands that have regenerated following clearcutting (51 years since harvest) and fire (92 years since fire), with multivariate regression trees. Taxa were more similar in the three controls (including recent fire) than between controls and harvest treatments, with increased forest floor disturbance in harvested plots being a likely explanation. In addition, taxa were different in the younger (51 years) harvest-origin plots than in the older (92 years) fire-origin plots, suggesting that communities had not yet recovered from the harvest disturbance possibly due to insufficient coarse woody debris in the younger stand. These results indicate that forest management practices that match natural forest floor disturbance could ameliorate short-term effects, whereas the maintenance of more coarse woody debris could reduce the recovery time of epigaeic communities.
Tackling tangledness of cosmic strings by knot polynomial topological invariants
Authors: Li Xinfei , Liu Xin , Huang Yong-Chang
Published: September 2017

Cosmic strings in the early universe have received revived interest in recent years. In this paper, we derive these structures as topological defects from singular distributions of the quintessence field of dark energy. Our emphasis is placed on the topological charge of tangled cosmic strings, which originates from the Hopf mapping and is a Chern–Simons action possessing strong inherent tie to knot topology. It is shown that the Kauffman bracket knot polynomial can be constructed in terms of this charge for unoriented knotted strings, serving as a topological invariant much stronger than the traditional Gauss linking numbers in characterizing string topology. Especially, we introduce a mathematical approach of breaking-reconnection which provides a promising candidate for studying physical reconnection processes within the complexity-reducing cascades of tangled cosmic strings.
The Higgs boson decay into ZZ decaying to identical fermion pairs
Authors: Zagoskin Taras V. , Korchin Alexander Yu.
Published: September 2017

In order to investigate various decay channels of the Higgs boson [Formula: see text] or the hypothetical dilaton, we consider a neutral particle [Formula: see text] with zero spin and arbitrary [Formula: see text] parity. This particle can decay into two off-mass-shell [Formula: see text] bosons ([Formula: see text] and [Formula: see text]) decaying to identical fermion–antifermion pairs ([Formula: see text]): [Formula: see text]. We derive analytical formulas for the fully differential width of this decay and for the fully differential width of [Formula: see text] ([Formula: see text] stands for [Formula: see text], [Formula: see text], or [Formula: see text]). Integration of these formulas yields some Standard Model histogram distributions of the decay [Formula: see text] which are compared with corresponding Monte Carlo simulated distributions obtained by ATLAS and with ATLAS experimental data.
Propagation of Gamma packets on de Sitter space–time
Authors: Chilom Alin-Nicolae
Published: September 2017

The (1[Formula: see text]+[Formula: see text]1) scalar quantum mechanics on the de Sitter space–time is outlined focusing on the momentum-energy statistics and the propagation of the packets that minimize the uncertainty relation between energy and momentum.
Global weak solutions in a three-dimensional Keller–Segel–Navier–Stokes system with subcritical sensitivity
Authors: Wang Yulan
Published: September 2017

This paper deals with the Keller–Segel–Navier–Stokes system [Formula: see text] in a bounded domain [Formula: see text] with smooth boundary, where [Formula: see text] and [Formula: see text] are given functions. We shall develop a weak solution concept which requires solutions to satisfy very mild regularity hypotheses only, especially for the component [Formula: see text]. Under the assumption that there exist [Formula: see text] and [Formula: see text] such that [Formula: see text] it is finally shown that for all suitably regular initial data an associated initial-boundary value problem possesses a globally defined weak solution. In comparison to the result for the corresponding fluid-free system, it is easy to see that the restriction on [Formula: see text] here is optimal. This result extends previous studies on global solvability for this system in the two-dimensional domain and for the associated chemotaxis-Stokes system obtained on neglecting the nonlinear convective term in the fluid equation.
Some U(n1 + n2) ⊃U(n1) ⊗U(n2) isoscalar factors
Authors: Ganev H. G.
Published: September 2017

Some of the [Formula: see text] isoscalar factors (IFs), involving the [Formula: see text] couplings of the type [Formula: see text], are obtained using the building-up procedure. It is shown that such type of IFs are relevant to the quantum-mechanical treatment of the two-component many-body systems.
A GENERALIZED PREDATOR–PREY SYSTEM WITH HABITAT COMPLEXITY
Authors: MA ZHIHUI , WANG SHUFAN , WANG TINGTING , TANG HAOPENG , LI ZIZHEN
Published: September 2017

This paper presents a generalized predator–prey system and considers the effect of habitat complexity on the dynamical consequences. The results show that habitat complexity has a major impact on the dynamical consequences of the considered system. On the one hand, habitat complexity has a stabilizing impact under certain conditions. A numerical simulation in our study and in experiments conducted in the published studies elaborate on this stabilizing effect. On the other hand, the most interesting and open issue is that a destabilizing effect of habitat complexity is found theoretically. All results are explained and illustrated from the ecological viewpoint.
NUMERICAL PRICING OF CoCo BONDS WITH PARISIAN TRIGGER FEATURE USING THE FORTET METHOD
Authors: LEUNG CHI MAN , KWOK YUE KUEN
Published: September 2017

Unlike conventional convertible bonds, contingent convertible (CoCo) bonds are converted into equity shares of the issuing bank subject to certain trigger mechanisms (accounting and/or regulatory trigger) when the issuing bank is under financial nonviable state. We consider pricing of these CoCo bonds using the contingent claims approach, where the state variables are the stock price and Tier 1 capital ratio. We use the Parisian feature to model the regulatory trigger where equity conversion is triggered when the capital ratio stays under the nonviable state consecutively for a certain period of time. The accounting trigger is modeled using the one-touch barrier feature associated with the capital ratio. The Parisian trigger feature adds one extra path dependent state variable in the pricing model of a CoCo bond. We design effective numerical algorithms for pricing the CoCo bonds using the extended Fortet method that avoid adding one extra state variable for the Parisian feature of regulatory trigger. Pricing properties of the CoCo bonds under both regulatory trigger and accounting trigger are explored.
Generating degrees for graded projective resolutions
Authors: Marcos Eduardo N. , Solotar Andrea , Volkov Yury
Published: September 2017

We provide a framework connecting several well-known theories related to the linearity of graded modules over graded algebras. In the first part, we pay a particular attention to the tensor products of graded bimodules over graded algebras. Finally, we provide a tool to evaluate the possible degrees of a module appearing in a graded projective resolution once the generating degrees for the first term of some particular projective resolution are known.
Directed Fuzzy Networks as a Model to Illicit Flows and Max Flow Min Cut Theorem
Authors: Mathew Sunil , Mordeson John N.
Published: September 2017

Directed fuzzy networks are introduced in this paper. They are normalized node capacitated networks and provide a good platform to model different types of complicated flows in nature. A directed fuzzy network version of Menger’s theorem and the celebrated Max flow Min cut theorem are also provided. Since the maximum flow through minimum number of directed internally disjoint paths is important in quality of service (QoS) problems in networking, the results in this paper can be applied to a wide variety of problems.
Local Look at Human Trafficking
Authors: Mordeson John N. , Mathew Sunil
Published: September 2017

We use expert opinion to determine linear equations that aid in determining how well a local area in the state of Nebraska, USA, is doing in combating sex trafficking. The mathematical model used here can be expanded to larger regions such as states or countries. Our results are in agreement with those of Shared Hope International. We also use outranking relations to determine experts’ preferences.
Statistical Convergence of Complex Uncertain Sequences
Authors: Tripathy Binod Chandra , Nath Pankaj Kumar
Published: September 2017

Complex uncertain variables are measurable functions from an uncertainty space to the set of complex numbers and are used to model complex uncertain quantities. This paper introduces the statistical convergence concepts of complex uncertain sequences: statistical convergence almost surely (a.s.), statistical convergence in measure, statistical convergence in mean, statistical convergence in distribution and statistical convergence uniformly almost surely (u.a.s.) In addition, decomposition theorems and relationships among them are discussed.
T-joins in strongly connected hypergraphs
Authors: Calinescu Gruia
Published: September 2017

Given an edge-weighted undirected hypergraph [Formula: see text] and an even-sized set of vertices [Formula: see text], a T-cut is a partition of [Formula: see text] into two parts [Formula: see text] and [Formula: see text] such that [Formula: see text] is odd. A T-join in [Formula: see text] for [Formula: see text] is a set of hyperedges [Formula: see text] such that for every T-cut [Formula: see text] there is a hyperedge [Formula: see text] intersecting both [Formula: see text] and [Formula: see text].

A directed hypergraph has for every hyperedge exactly one vertex, called the head, and several vertices, that are tails. A directed hypergraph is strongly connected if there exists at least one directed path between any two vertices of the hypergraph, where a directed path is defined to be a sequence of vertices and hyperedges for which each hyperedge has as one of its tails the vertex preceding it and as its head the vertex following it in the sequence. Orienting an undirected hypergraph means choosing a head for each hyperedge.

We prove that every edge-weighted undirected hypergraph that admits a strongly connected orientation has a T-join of total weight at most [Formula: see text] times the total weight of all the edges of the hypergraph, and sketch an improvement to [Formula: see text]. We also exhibit a series of example showing that one cannot improve the constant above to [Formula: see text].
The Kangaroo, the Bear, and the Dragon: Australia-Russia-China Relations in the “Asian Century”
Authors: Antonopoulos Paul
Published: September 2017

With Australia and Russia increasingly seeing their future in the Asia-Pacific, neither can reach its full economic potential except under the guidance of Beijing’s control of ports on its “Maritime Silk Road.” Cold War clichés of the “Yankee lapdog” and the big bad “Russian bear” continue to dominate how Canberra and Moscow view each other. Yet when it comes to the future of Australia-Russia-China relations, one must look beyond Moscow, Beijing, and Canberra, but rather at Vladivostok and Darwin, symbols of an as-yet unrealized goal to shift emphasis onto each country’s sparsely-populated regions bordering the Asia-Pacific. With the dawning of the “Asian Century,” how does the United States change the geopolitical dynamics of the region, and how do China, Russia, and Australia react to “America’s Pacific Century”? Rather than a capitulation to America’s aggressive posture in the Asia-Pacific, China and Russia have consolidated the integration of their economies and militaries to counter such penetration. This emerging rivalry creates a challenge for Australia to balance its military alliance with the United States and its economic reliance on China. The necessity of finetuning this balance should be Canberra’s primary foreign policy issue.
Banks’ capital regulation and risk: Does bank vary in size? Empirical evidence from Bangladesh
Authors: Zheng Changjun , Moudud-Ul-Huq Syed
Published: September 2017

This paper primarily examines both causality effect of banks’ capital regulation and risk-taking behavior based on generalized methods of moment (GMM) for a dynamic unbalanced panel observation of 32 commercial banks in Bangladesh over the period 2000–2014. The empirical findings of this study suggest that capital regulation has a significant effect on risk-taking behavior, and excessive risks impede the growth of capital ratio as well as the stability. Moreover, from bank-level data, size does not uniformly affect the quantity of capital and risk. Large banks have poor capital ratio and higher inclination to risk than small size counterpart. Small size banks are well managed in capital ratio and risk-taking that glitter their stability through the periods. Besides these effects, corporate governance notably influenced banks to reduce credit risk and enhance stability. Finally, this paper provides some implications for the think tanks and stakeholders of the country.
MC-ADAPT
Authors: Lee Jaewoo , Chwa Hoon Sung , Phan Linh T. X. , Shin Insik , Lee Insup
Published: September 2017

Recent embedded systems are becoming integrated systems with components of different criticality. To tackle this, mixed-criticality systems aim to provide different levels of timing assurance to components of different criticality levels while achieving efficient resource utilization. Many approaches have been proposed to execute more lower-criticality tasks without affecting the timeliness of higher-criticality tasks. Those previous approaches however have at least one of the two limitations; i) they penalize all lower-criticality tasks at once upon a certain situation, or ii) they make the decision how to penalize lower-criticality tasks at design time. As a consequence, they under-utilize resources by imposing an excessive penalty on low-criticality tasks. Unlike those existing studies, we present a novel framework, called MC-ADAPT, that aims to minimally penalize lower-criticality tasks by fully reflecting the dynamically changing system behavior into adaptive decision making. Towards this, we propose a new scheduling algorithm and develop its runtime schedulability analysis capable of capturing the dynamic system state. Our proposed algorithm adaptively determines which task to drop based on the runtime analysis. To determine the quality of task dropping solution, we propose the speedup factor for task dropping while the conventional use of the speedup factor only evaluates MC scheduling algorithms in terms of the worst-case schedulability. We apply the speedup factor for a newly-defined task dropping problem that evaluates task dropping solution under different runtime scheduling scenarios. We derive that MC-ADAPT has a speedup factor of 1.619 for task drop. This implies that MC-ADAPT can behave the same as the optimal scheduling algorithm with optimal task dropping strategy does under any runtime scenario if the system is sped up by a factor of 1.619.
Runtime Enforcement of Cyber-Physical Systems
Authors: Pinisetty Srinivas , Roop Partha S. , Smyth Steven , Allen Nathan , Tripakis Stavros , Hanxleden Reinhard Von
Published: September 2017

Many implantable medical devices, such as pacemakers, have been recalled due to failure of their embedded software. This motivates rethinking their design and certification processes. We propose, for the first time, an additional layer of safety by formalising the problem of run-time enforcement of implantable pacemakers. While recent work has formalised run-time enforcement of reactive systems, the proposed framework generalises existing work along the following directions: (1) we develop bi-directional enforcement, where the enforced policies depend not only on the status of the pacemaker (the controller) but also of the heart (the plant), thus formalising the run-time enforcement problem for cyber-physical systems (2) we express policies using a variant of discrete timed automata (DTA), which can cover all regular properties unlike earlier frameworks limited to safety properties, (3) we are able to ensure the timing safety of implantable devices through the proposed enforcement, and (4) we show that the DTA-based approach is efficient relative to its dense time variant while ensuring that the discretisation error is relatively small and bounded. The developed approach is validated through a prototype system implemented using the open source KIELER framework. The experiments show that the framework incurs minimal runtime overhead.
Improving Invariant Mining via Static Analysis
Authors: Schulze Christoph , Cleaveland Rance
Published: September 2017

This paper proposes the use of static analysis to improve the generation of invariants from test data extracted from Simulink models. Previous work has shown the utility of such automatically generated invariants as a means for updating and completing system specifications; they also are useful as a means of understanding model behavior. This work shows how the scalability and accuracy of the data mining process can be dramatically improved by using information from data/control flow analysis to reduce the search space of the invariant mining and to eliminate false positives. Comparative evaluations of the process show that the improvements significantly reduce execution time and memory consumption, thereby supporting the analysis of more complex models, while also improving the accuracy of the generated invariants.
Response-Time Analysis for Task Chains with Complex Precedence and Blocking Relations
Authors: Schlatow Johannes , Ernst Rolf
Published: September 2017

For the development of complex software systems, we often resort to component-based approaches that separate the different concerns, enhance verifiability and reusability, and for which microkernel-based implementations are a good fit to enforce these concepts. Composing such a system of several interacting software components will, however, lead to complex precedence and blocking relations, which must be taken into account when performing latency analysis. When modelling these systems by classical task graphs, some of these effects are obfuscated and tend to render such an analysis either overly pessimistic or even optimistic.

We therefore firstly present a novel task (meta-)model that is more expressive and accurate w.r.t. these (functional) precedence and mutual blocking relations. Secondly, we apply the busy-window approach and formulate a modular response-time analysis on task-chain level suitable but not restricted to static-priority scheduled systems. We show that the conjunction of both concepts allows the calculation of reasonably tight latency bounds for scenarios not adequately covered by related work.
Security-Aware Scheduling of Embedded Control Tasks
Authors: Lesi Vuk , Jovanov Ilija , Pajic Miroslav
Published: September 2017

In this work, we focus on securing cyber-physical systems (CPS) in the presence of network-based attacks, such as
Man-in-the-Middle
(MitM) attacks, where a stealthy attacker is able to compromise communication between system sensors and controllers. Standard methods for this type of attacks rely on the use of cryptographic mechanisms, such as Message Authentication Codes (MACs) to ensure data integrity. However, this approach incurs significant computation overhead, limiting its use in resource constrained systems. Consequently, we consider the problem of scheduling multiple control tasks on a shared processor while providing a suitable level of security guarantees. Specifically, by security guarantees we refer to control performance, i.e., Quality-of-Control (QoC), in the presence of attacks. We start by mapping requirements for QoC under attack into constraints for security-aware control tasks that, besides standard control operations, intermittently perform data authentication. This allows for the analysis of the impact that security-related computation overhead has on both schedulability of control tasks and QoC. Building on this analysis, we introduce a mixed-integer linear programming-based technique to obtain a schedulable task set with predefined QoC requirements. Also, to facilitate optimal resource allocation, we provide a method to analyze interplay between available computational resources and the overall QoC under attack, and show how to obtain a schedulable task set that maximizes the overall QoC guarantees. Finally, we prove usability of our approach on a case study with multiple automotive control components.
Testing Cyber-Physical Systems through Bayesian Optimization
Authors: Deshmukh Jyotirmoy , Horvat Marko , Jin Xiaoqing , Majumdar Rupak , Prabhu Vinayak S.
Published: September 2017

Many problems in the design and analysis of cyber-physical systems (CPS) reduce to the following optimization problem: given a CPS which transforms continuous-time input traces in R

m

to continuous-time output traces in R
n
and a cost function over output traces, find an input trace which minimizes the cost. Cyber-physical systems are typically so complex that solving the optimization problem analytically by examining the system dynamics is not feasible. We consider a black-box approach, where the optimization is performed by testing the input-output behaviour of the CPS.

We provide a unified, tool-supported methodology for CPS testing and optimization. Our tool is the first CPS testing tool that supports Bayesian optimization. It is also the first to employ fully automated dimensionality reduction techniques. We demonstrate the potential of our tool by running experiments on multiple industrial case studies. We compare the effectiveness of Bayesian optimization to state-of-the-art testing techniques based on CMA-ES and Simulated Annealing.