bluuebunny/crossref_metadata_2025 huggingface dataset:
Epidemiological survey of the feasibility of broadband ultrasound attenuation measured using calcaneal quantitative ultrasound to predict the incidence of falls in the middle aged and elderly
Authors: Ou Ling-Chun , Chang Yin-Fan , Chang Chin-Sung , Chiu Ching-Ju , Chao Ting-Hsing , Sun Zih-Jie , Lin Ruey-Mo , Wu Chih-Hsing
Published: January 2017

Objectives

We investigated whether calcaneal quantitative ultrasound (QUS-C) is a feasible tool for predicting the incidence of falls.

Design

Prospective epidemiological cohort study.

Setting

Community-dwelling people sampled in central western Taiwan.

Participants

A cohort of community-dwelling people who were ≥40 years old (men: 524; women: 676) in 2009–2010. Follow-up questionnaires were completed by 186 men and 257 women in 2012.

Methods

Structured questionnaires and broadband ultrasound attenuation (BUA) data were obtained in 2009–2010 using QUS-C, and follow-up surveys were done in a telephone interview in 2012. Using a binary logistic regression model, the risk factors associated with a new fall during follow-up were analysed with all significant variables from the bivariate comparisons and theoretically important variables.

Primary outcome measures

The incidence of falls was determined when the first new fall occurred during the follow-up period. The mean follow-up time was 2.83 years.

Results

The total incidence of falls was 28.0 per 1000 person-years for the ≥40 year old group (all participants), 23.3 per 1000 person-years for the 40–70 year old group, and 45.6 per 1000 person-years for the ≥70 year old group. Using multiple logistic regression models, the independent factors were current smoking, living alone, psychiatric drug usage and lower BUA (OR 0.93; 95% CI 0.88 to 0.99, p<0.05) in the ≥70 year old group.

Conclusions

The incidence of falls was highest in the ≥70 year old group. Using QUS-C-derived BUA is feasible for predicting the incidence of falls in community-dwelling elderly people aged ≥70 years.
External validation of the Revised Cardiac Risk Index and update of its renal variable to predict 30-day risk of major cardiac complications after non-cardiac surgery: rationale and plan for analyses of the VISION study
Authors: Roshanov Pavel S , Walsh Michael , Devereaux P J , MacNeil S Danielle , Lam Ngan N , Hildebrand Ainslie M , Acedillo Rey R , Mrkobrada Marko , Chow Clara K , Lee Vincent W , Thabane Lehana , Garg Amit X
Published: January 2017

Introduction

The Revised Cardiac Risk Index (RCRI) is a popular classification system to estimate patients' risk of postoperative cardiac complications based on preoperative risk factors. Renal impairment, defined as serum creatinine >2.0 mg/dL (177 µmol/L), is a component of the RCRI. The estimated glomerular filtration rate has become accepted as a more accurate indicator of renal function. We will externally validate the RCRI in a modern cohort of patients undergoing non-cardiac surgery and update its renal component.

Methods and analysis

The Vascular Events in Non-cardiac Surgery Patients Cohort Evaluation (VISION) study is an international prospective cohort study. In this prespecified secondary analysis of VISION, we will test the risk estimation performance of the RCRI in ∼34 000 participants who underwent elective non-cardiac surgery between 2007 and 2013 from 29 hospitals in 15 countries. Using data from the first 20 000 eligible participants (the derivation set), we will derive an optimal threshold for dichotomising preoperative renal function quantified using the Chronic Kidney Disease Epidemiology Collaboration (CKD-Epi) glomerular filtration rate estimating equation in a manner that preserves the original structure of the RCRI. We will also develop a continuous risk estimating equation integrating age and CKD-Epi with existing RCRI risk factors. In the remaining (approximately) 14 000 participants, we will compare the risk estimation for cardiac complications of the original RCRI to this modified version. Cardiac complications will include 30-day non-fatal myocardial infarction, non-fatal cardiac arrest and death due to cardiac causes. We have examined an early sample to estimate the number of events and the distribution of predictors and missing data, but have not seen the validation data at the time of writing.

Ethics and dissemination

The research ethics board at each site approved the VISION protocol prior to recruitment. We will publish our results and make our models available online athttp://www.perioperativerisk.com.

Trial registration number

ClinicalTrials.govNCT00512109.
Paramedics' views on their seizure management learning needs: a qualitative study in England
Authors: Sherratt Frances C , Snape Darlene , Goodacre Steve , Jackson Mike , Pearson Mike , Marson Anthony G , Noble Adam J
Published: January 2017

Introduction

The UK ambulance service often attends to suspected seizures. Most persons attended to will not require the facilities of a hospital emergency department (ED) and so should be managed at scene or by using alternative care pathways. Most though are transported to ED. One factor that helps explain this is paramedics can have low confidence in managing seizures.

Objectives

With a view to ultimately developing additional seizure management training for practicing paramedics, we explored their learning needs, delivery preferences and potential drivers and barriers to uptake and effectiveness.

Design and setting

Semistructured interviews were conducted with a purposive sample of paramedics from the English ambulance service. Interviews were transcribed and thematically analysed.

Participants

A diverse sample of 19 professionals was recruited from 5 different ambulance NHS trusts and the College of Paramedics.

Results

Participants said seizure management was neglected within basic and postregistration paramedic training. Most welcomed additional learning opportunities and identified gaps in knowledge. This included how to differentiate between seizure types and patients that do and do not need ED. Practical, interactive e-learning was deemed the most preferable delivery format. To allow paramedics to fully implement any increase in skill resulting from training, organisational and structural changes were said to be needed. This includes not penalising paramedics for likely spending longer on scene.

Conclusions

This study provides the first evidence on the learning needs and preferences of paramedics regarding seizures. It can be used to inform the development of a bespoke training programme for paramedics. Future research should develop and then assess the benefit such training has on paramedic confidence and on the quality of care they offer to seizure patients.
What aspects of intentional rounding work in hospital wards, for whom and in what circumstances? A realist evaluation protocol
Authors: Harris Ruth , Sims Sarah , Levenson Ros , Gourlay Stephen , Ross CBE Fiona , Davies Nigel , Brearley Sally , Favato Giampiero , Grant Robert
Published: January 2017

Introduction

Intentional rounding (IR) is a structured process whereby nurses in hospitals carry out regular checks, usually hourly, with individual patients using a standardised protocol to address issues of positioning, pain, personal needs and placement of items. The widespread implementation of IR across the UK has been driven by the recommendations of the Francis Inquiry although empirical evidence of its effectiveness is poor. This paper presents a protocol of a multimethod study using a realist evaluation approach to investigate the impact and effectiveness of IR in hospital wards on the organisation, delivery and experience of care from the perspective of patients, their family members and staff.

Methods and analysis

The study will be conducted in four phases. Phase 1: theory development using realist synthesis to generate hypotheses about what the mechanisms of IR may be, what particular groups may benefit most or least and what contextual factors might be important to its success or failure which will be tested in subsequent phases of the study. Phase 2: a national survey of all NHS acute trusts to explore how IR is implemented and supported across England. Phase 3: case studies to explore how IR is implemented ‘on the ground’, including individual interviews with patients, family members and staff, non-participant observation, retrieval of routinely collected patient outcomes and cost analysis. Phase 4: accumulative data analysis across the phases to scrutinise data for patterns of congruence and discordance and develop an overall evaluation of what aspects of IR work, for whom and in what circumstances.

Ethics and dissemination

The study has been approved by NHS South East Coast—Surrey Research Ethics Committee. Findings will be published in a wide range of outputs targeted at key audiences, including patient and carer organisations, nursing staff and healthcare managers.
Meat intake and risk of diverticulitis among men
Authors: Cao Yin , Strate Lisa L , Keeley Brieze R , Tam Idy , Wu Kana , Giovannucci Edward L , Chan Andrew T
Published: January 2017

Objective

Diverticulitis is a common disease with a substantial clinical and economic burden. Besides dietary fibre, the role of other foods in the prevention of diverticulitis is underexplored.

Design

We prospectively examined the association between consumption of meat (total red meat, red unprocessed meat, red processed meat, poultry and fish) with risk of incident diverticulitis among 46 461 men enrolled in the Health Professionals Follow-Up Study (1986–2012). Cox proportional hazards models were used to compute relative risks (RRs) and 95% CIs.

Results

During 651 970 person-years of follow-up, we documented 764 cases of incident diverticulitis. Compared with men in the lowest quintile (Q1) of total red meat consumption, men in the highest quintile (Q5) had a multivariable RR of 1.58 (95% CI 1.19 to 2.11; p for trend=0.01). The increase in risk was non-linear, plateauing after six servings per week (p for non-linearity=0.002). The association was stronger for unprocessed red meat (RR for Q5 vs Q1: 1.51; 95% CI 1.12 to 2.03; p for trend=0.03) than for processed red meat (RR for Q5 vs Q1: 1.03; 95% CI 0.78 to 1.35; p for trend=0.26). Higher consumption of poultry or fish was not associated with risk of diverticulitis. However, the substitution of poultry or fish for one serving of unprocessed red meat per day was associated with a decrease in risk of diverticulitis (multivariable RR 0.80; 95% CI 0.63 to 0.99).

Conclusions

Red meat intake, particularly unprocessed red meat, was associated with an increased risk of diverticulitis. The findings provide practical dietary guidance for patients at risk of diverticulitis.
Coeliac disease screening is suboptimal in a tertiary gastroenterology setting
Authors: Iskandar Heba , Gray Darrell M , Vu Hongha , Mirza Faiz , Rude Mary Katherine , Regan Kara , Abdalla Adil , Gaddam Srinivas , Almaskeen Sami , Mello Michael , Marquez Evelyn , Meyer Claire , Bolkhir Ahmed , Kanuri Navya , Sayuk Gregory , Gyawali C Prakash
Published: January 2017

Background and aims

Coeliac disease (CD) is widely prevalent in North America, but case-finding techniques currently used may not be adequate for patient identification. We aimed to determine the adequacy of CD screening in an academic gastroenterology (GI) practice.

Methods

Consecutive initial visits to a tertiary academic GI practice were surveyed over a 3-month period as a fellow-initiated quality improvement project. All electronic records were reviewed to look for indications for CD screening according to published guidelines. The timing of screening was noted (before or after referral), as well as the screening method (serology or biopsy). Data were analysed to compare CD screening practices across subspecialty clinics.

Results

616 consecutive patients (49±0.6 years, range 16–87 years, 58.5% females, 94% Caucasian) fulfilled inclusion criteria. CD testing was indicated in 336 (54.5%), but performed in only 145 (43.2%). The need for CD screening was highest in luminal GI and inflammatory bowel disease clinics, followed by biliary and hepatology clinics (p<0.0001); CD screening rate was highest in the luminal GI clinic (p=0.002). Of 145 patients screened, 4 patients (2.4%) had serology consistent with CD, of which 2 were proven by duodenal biopsy. Using this proportion, an additional 5 patients might have been diagnosed in 191 untested patients with indications for CD screening.

Conclusions

More than 50% of patients in a tertiary GI clinic have indications for CD screening, but <50% of indicated cases are screened. Case-finding techniques therefore are suboptimal, constituting a gap in patient care and an important target for future quality improvement initiatives.
Non-alcoholic fatty pancreas disease
Authors: Alempijevic Tamara , Dragasevic Sanja , Zec Simon , Popovic Dragan , Milosavljevic Tomica
Published: January 2017

Obesity is a growing problem worldwide and disorders associated with excess body fat including the metabolic syndrome, type 2 diabetes mellitus (T2DM), cardiovascular disease and malignant neoplasms are becoming a major cause of morbidity and mortality. Over the past decade, a vast amount of research has furthered our understanding of non-alcoholic fatty liver disease; however, only recently pancreatic fat infiltration is coming to the forefront of investigation. Termed non-alcoholic fatty pancreas disease (NAFPD), it is becoming evident that it has important associations with other diseases of obesity. It appears to arise as obesity progresses and after an initial phase of pancreatic hypertrophy and hyperplasia, fatty infiltration becomes apparent. Various studies have demonstrated that NAFPD may exacerbate the severity of acute pancreatitis, promote pancreatic dysfunction associated with insulin resistance and T2DM, and even have links to the development of pancreatic carcinoma, and therefore, it must be investigated in further detail.
Mean-field analysis of two-species totally asymmetric simple exclusion process (TASEP) with attachment and detachment
Authors: Song Minghua , Zhang Yunxin
Published: January 2017

In the field of statistical physics, unidirectional motion of a large number of particles along a single track can be described by totally asymmetric simple exclusion process (TASEP), from which many meaningful properties, such as the appearance of domain wall (defined as the borderline of high particle density and low particle density along the motion track) and boundary layers, can be obtained. However, it is biologically general that a single track may be occupied by different particle species. For example, in cells each microtubule protofilament is usually occupied by different species of motor protein. So previous studies about TASEP that included only one particle species may not be reasonable enough to describe more detailed properties of particle motion processes in a real cell environment. To address this problem, TASEP including two particle species is discussed in this study. Theoretical methods to get particle densities of each species are provided. By which, phase transition related properties of particle densities are obtained. Our analysis shows that domain wall and boundary layers of single species densities always appear simultaneously with those of the total particle density. The height of the domain wall of total particle density is equal to the summation of those of single particle species. Phase diagrams for typical model parameters are also presented. The methods presented in this study can be generalized to analyze TASEP with more particle species.
A Multiple-Plasticity Spiking Neural Network Embedded in a Closed-Loop Control System to Model Cerebellar Pathologies
Authors: Geminiani Alice , Casellato Claudia , Antonietti Alberto , D’Angelo Egidio , Pedrocchi Alessandra
Published: January 2017

The cerebellum plays a crucial role in sensorimotor control and cerebellar disorders compromise adaptation and learning of motor responses. However, the link between alterations at network level and cerebellar dysfunction is still unclear. In principle, this understanding would benefit of the development of an artificial system embedding the salient neuronal and plastic properties of the cerebellum and operating in closed-loop. To this aim, we have exploited a realistic spiking computational model of the cerebellum to analyze the network correlates of cerebellar impairment. The model was modified to reproduce three different damages of the cerebellar cortex: (i) a loss of the main output neurons (Purkinje Cells), (ii) a lesion to the main cerebellar afferents (Mossy Fibers), and (iii) a damage to a major mechanism of synaptic plasticity (Long Term Depression). The modified network models were challenged with an Eye-Blink Classical Conditioning test, a standard learning paradigm used to evaluate cerebellar impairment, in which the outcome was compared to reference results obtained in human or animal experiments. In all cases, the model reproduced the partial and delayed conditioning typical of the pathologies, indicating that an intact cerebellar cortex functionality is required to accelerate learning by transferring acquired information to the cerebellar nuclei. Interestingly, depending on the type of lesion, the redistribution of synaptic plasticity and response timing varied greatly generating specific adaptation patterns. Thus, not only the present work extends the generalization capabilities of the cerebellar spiking model to pathological cases, but also predicts how changes at the neuronal level are distributed across the network, making it usable to infer cerebellar circuit alterations occurring in cerebellar pathologies.
Epileptic Discharge Related Functional Connectivity Within and Between Networks in Benign Epilepsy with Centrotemporal Spikes
Authors: Li Rong , Ji Gong-Jun , Yu Yangyang , Yu Yang , Ding Mei-Ping , Tang Ye-Lei , Chen Huafu , Liao Wei
Published: January 2017

Benign epilepsy with centrotemporal spikes (BECTS) is a common childhood epilepsy syndrome associated with abnormalities in neurocognitive domains, particularly during interictal epileptiform discharges (IEDs). Here, we investigated the effects of IEDs on brain’s intrinsic connectivity networks in 43 BECTS patients and 28 matched healthy controls (HCs). Patients were further divided into IED and non-IED subgroups based on simultaneous EEG-fMRI recordings. Functional connectivity within and between five networks, corresponding to seizure origination and cognitive processes, were analyzed to measure IED effects. We found that patients exhibited increased connectivity within the auditory network (AN) and the somato-motor network (SMN), and decreased connectivity within the basal ganglia network and the dorsal attention network, suggesting that both transient and chronic seizure activity may disturb normal network organization. The IED group showed decreased functional connectivity within the default mode network (DMN) compared with the non-IED group and HCs, implying that the DMN was selectively impaired during epileptiform discharges associated with altered self-referential cognitive functions. Moreover, the IED group exhibited increased positive correlations between the AN and the SMN, which suggests a possible excessive influence of centrotemporal spiking on information processing in the auditory system. The association between epileptic activity and network dysfunctions highlights their importance in investigating the pathological mechanism underlying BECTS.
An implicit-explicit finite-difference lattice Boltzmann subgrid method on nonuniform meshes
Authors: Qiu Ruofan , Chen Rongqian , You Yancheng
Published: January 2017

In this paper, an implicit-explicit finite-difference lattice Boltzmann method with subgrid model on nonuniform meshes is proposed. The implicit-explicit Runge–Kutta scheme, which has good convergence rate, is used for the time discretization and a mixed difference scheme, which combines the upwind scheme with the central scheme, is adopted for the space discretization. Meanwhile, the standard Smagorinsky subgrid model is incorporated into the finite-difference lattice Boltzmann scheme. The effects of implicit-explicit Runge–Kutta scheme and nonuniform meshes of present lattice Boltzmann method are discussed through simulations of a two-dimensional lid-driven cavity flow on nonuniform meshes. Moreover, the comparison simulations of the present method and multiple relaxation time lattice Boltzmann subgrid method are conducted qualitatively and quantitatively.
Relativistic model of neutron stars in X-ray binary
Authors: Kalam Mehedi , Hossein Sk Monowar , Islam Rabiul , Molla Sajahan
Published: January 2017

In this paper, we study the inner structure of some neutron stars from theoretical as well as observational points of view. We calculate the probable radii, compactness (u) and surface redshift (Z[Formula: see text]) of five neutron stars (X-ray binaries) namely 4U 1538-52, LMC X-4, 4U 1820-30, 4U 1608-52, EXO 1745-248. Here, we propose a stiff equation of state (EoS) of matter distribution which relates pressure with matter density. Finally, we check the stability of such kind of theoretical structure.
On sutured Khovanov homology and axis-preserving mutations
Authors: Hubbard Diana
Published: January 2017

This paper establishes that sutured annular Khovanov homology is not invariant for braid closures under axis-preserving mutations. This follows from an explicit relationship between sutured annular Khovanov homology and the classical Burau representation for braid closures.
Polynomial invariants via odd parities for virtual link diagrams
Authors: Im Young Ho , Kim Sera , Park Kyoung Il
Published: January 2017

We introduce the odd index polynomial and the odd arrow polynomial for virtual links which are different from the original index polynomial and arrow polynomial.
In search of a pristine signal for (scale-)chiral symmetry in nuclei
Authors: Rho Mannque
Published: January 2017

I describe the long-standing search for a “smoking-gun” signal for the manifestation of (scale-)chiral symmetry in nuclear interactions. It is prompted by Gerry Brown’s last unpublished note, reproduced verbatim below, on the preeminent role of pions and vector ([Formula: see text]) mesons in providing a simple and elegant description of strongly correlated nuclear interactions. In this note written in tribute to Gerry Brown, I first describe a case of an unambiguous signal in axial-charge transitions in nuclei and then combine his ideas with the more recent development on the role of hidden symmetries in nuclear physics. What transpires is the surprising conclusion that the Landau–Migdal fixed point interaction [Formula: see text], the nuclear tensor forces and Brown–Rho scaling, all encoded in scale-invariant hidden local symmetry, as Gerry put, “run the show and make all forces equal.”
Pathways of NO adsorption on Si(100)2×1 by van der Waals corrected DFT
Authors: Carbone Marilena
Published: January 2017

In the current study, the NO adsorption on the Si(100) surface was investigated by DFT including van der Waals forces (vdW). Stable molecular and dissociative configurations were found and compared to previous studies. Furthermore, additional states were investigated where NO adsorbs across dimers. The transformation of NO from molecular adsorbate into a dissociated adsorbate migrated into the subsurface was investigated by nudged elastic band. Several pathways were explored, either multi-staged, or direct from molecular into subsurface migrated configurations, both including and excluding vdW forces. The energy barriers of the single steps of multi-staged pathways never exceed 0.15[Formula: see text]eV and are, in general, smaller when NO is adsorbed across dimers rather than bridged on a single dimer and when including vdW. Furthermore, the oxygen-bridged configurations are kinetically more accessible than the nitrogen-bridged ones.
Wavelet analysis of the temporal-spatial distribution in the Eurasia seismic belt
Authors: Zheng Wenfeng , Li Xiaolu , Yin Lirong , Yin Zhengtong , Yang Bo , Liu Shan , Song Lihong , Zhou Yu , Li Yanhong
Published: January 2017

Due to the growing frequency of earthquakes, safeties of human lives and properties are facing serious threats. However, the research in the field of spatial-temporal distribution of earthquake is quite a few. In this paper, we use wavelet model to analyze the spatial-temporal distribution of earthquakes. Because the spatial-temporal distribution of earthquake activity is closely related to the distribution of the earthquake fault zone, we analyze large-scale earthquake clusters by selecting the Eurasia seismic belt and the surrounding region as the research area. From the perspective of the time domain, the results show that the seismic energy of the earthquake fault zone presences compact support or similar compact support distribution, suggesting that the seismic zone exists a relatively quiet period and active stage. This indicate that the seismic zone is periodical. The period of strong earthquakes above normal and less than normal is different by time changes. The cycles of earthquakes are different due to different regions and different geological and geographical environment.
Geometric quantization of the Hitchin system
Authors: Dey Rukmini
Published: January 2017

This paper is about geometric quantization of the Hitchin system. We quantize a Kahler form on the Hitchin moduli space (which is half the first Kahler form defined by Hitchin) by considering the Quillen bundle as the prequantum line bundle and modifying the Quillen metric using the Higgs field so that the curvature is proportional to the Kahler form. We show that this Kahler form is integral and the Quillen bundle descends as a prequantum line bundle on the moduli space. It is holomorphic and hence one can take holomorphic square integrable sections as the Hilbert space of quantization of the Hitchin moduli space.
Conformal, concircular, quasi-conformal and conharmonic flatness on normal complex contact metric manifolds
Authors: Turgut Vanli Aysel , Unal Inan
Published: January 2017

Conformal, concircular, quasi-conformal and conharmonic curvature tensors play an important role in Riemannian geometry. In this paper, we study on normal complex contact metric manifolds under flatness conditions of these tensors.
Photocatalytic Activity of Reduced Graphene Oxide-SnSe Nanohybrids with Efficiency Interface Effect
Authors: He H.-Y.
Published: January 2017

Reduced graphene oxide-SnSe (rGO-SnSe) nanohybrids were synthesized with a solution chemical reaction at room temperature. The nanohybrids were characterized by various techniques for their microstructural and photocatalytic activities in photodegradation of alkaline dye malachite green in the water. The effects of rGO/SnSe ratio, initial solution pH, and H2O2 concentration on the photodegradation efficiency were studied. The SnSe nanocrystallines with nanoscale size and narrow bandgap were formed and uniformly adhered on the rGO surface. Raman analysis confirmed the reduction of GO. The experimental results indicated that the nanohybrids showed excellent sunlight-excited photocatalytic activity in degrading malachite green in the water. Significantly, the nanohybrids showed remarkable photo-Fenton-like catalytic activity. The photodegradation rates of the hybrids were greater than that of SnSe nanoparticles, increased with increasing rGO/SnSe ratio, and related to operation parameters. High photocatalytic activities were ascribed to the efficiency interface effect that was confirmed by the calculations of band energy level and photoconductivity. The TOC measurement further verified the photodegradation results. The nanoparticles and nanohybrids also showed excellent reusability.
Adsorption Patterns of Helium on Carbon and Cellulose Nanotubes: Molecular Dynamics Simulations
Authors: Majidi Roya , Taghiyari Hamid Reza , Ekhlasi Mahsa
Published: January 2017

Molecular dynamics simulations were performed to study helium adsorption on carbon and cellulose nanotubes. Adsorption isotherms were analyzed at different temperatures and pressures. All adsorption isotherms for carbon and cellulose nanotubes were predicted to be of Langmuir shape type I. Helium adsorption was observed both inside and outside of open-ended tubes. Increasing temperatures caused lower helium adsorption on carbon and cellulose nanotubes. The calculated quantities confirmed that the adsorption capacity of the cellulose nanotube was greater than that of the carbon nanotube. The adsorption capacity, isosteric heat of adsorption and binding energy indicated that cellulose nanotubes as well as carbon nanotubes are proper materials for gas storage.
Pattern dynamics of a diffusive predator–prey model with delay effect
Authors: Hu Guangping , Li Xiaoling , Li Dongliang
Published: January 2017

We study the spatiotemporal dynamics in a diffusive predator–prey system with time delay. By investigating the dynamical behavior of the system in the presence of Turing–Hopf bifurcations, we present a classification of the pattern dynamics based on the dispersion relation for the two unstable modes. More specifically, we researched the existence of the Turing pattern when control parameters lie in the Turing space. Particularly, when parameter values are taken in Turing–Hopf domain, we numerically investigate the formation of all the possible patterns, including time-dependent wave pattern, persistent short-term competing dynamics and stationary Turing pattern. Furthermore, the effect of time delay on the formation of spatial pattern has also been analyzed from the aspects of theory and numerical simulation. We speculate that the interaction of spatial and temporal instabilities in the reaction–diffusion system might bring some insight to the finding of patterns in spatial predator–prey models.
Global threshold dynamics of SIQS epidemic model in time fluctuating environment
Authors: Li Shang , Fan Meng , Rong Xinmiao
Published: January 2017

The paper characterizes the global threshold dynamics of an epidemic model of SIQS type in environments with fluctuations, where the quarantine class is explicitly involved. Criteria are established for the permanence and extinction of the infective in environments with time oscillations. In particular, we further consider an environment which varies periodically in time. The global threshold dynamic scenarios i.e. the existence and global asymptotic stability of the disease-free periodic solution, the existence of the endemic periodic solution and the permanence of the infective are completely characterized by the basic reproduction number defined by the spectral radius of an associated linear integral operator.
Modeling the transmission of Buruli ulcer in fluctuating environments
Authors: Assan Belthasara , Nyabadza Farai , Landi Pietro , Hui Cang
Published: January 2017

The transmission dynamics of Buruli ulcer (BU) largely depends on environmental changes. In this paper a deterministic model for the transmission of BU in fluctuating environments is proposed. The model incorporates periodicity in the disease transmission pathways and the Mycobacterium ulcerans density that are thought to vary seasonally. Two reproduction numbers, the time-averaged reproduction number [Formula: see text] and the basic reproduction number [Formula: see text], are determined and compared. It is shown that the time-averaged reproduction underestimates the number of infections. Numerical simulations confirmed that if [Formula: see text] the infection is sustained seasonally. The model outcome suggests that environmental fluctuations should be taken into consideration in designing policies aimed at BU control and management.
A note on an age-of-infection SVIR model with nonlinear incidence
Authors: Yang Junyuan , Jin Zhen , Wang Lin , Xu Fei
Published: January 2017

In this paper, nonlinear incidence rate is incorporated into an age-of-infection SVIR epidemiological model. By the method of Lyapunov functionals, it is shown that the basic reproduction number [Formula: see text] of the model is a threshold parameter in the sense that if [Formula: see text], the disease dies out, while if [Formula: see text], the disease persists.
Phenomena associated with diffusion, assisted by moving interfaces in shape memory alloys: A review of our earlier studies
Authors: Kustov Sergey , Sapozhnikov Konstantin , Wang Xiebin
Published: January 2017

In this review, examples are given of a number of unusual phenomena, which we relate with the effect largely overlooked in shape memory alloys: diffusion of point-like defects, assisted by moving linear and planar defects — dislocations, twin and interphase boundaries.
Fast growth of amorphous Si nanowires by direct current arc plasma jet chemical vapor deposition
Authors: Wu Yongheng , Li Mingji , Li Cuiping , Wu Xiaoguo , Yang Baohe , Li Hongji
Published: January 2017

Silicon (Si) nanowires were synthesized by direct current arc plasma jet chemical vapor deposition. It was found that growth temperature and growth time played important roles in the morphologies of the Si nanowires. The possible formation mechanism of Si nanowire was also proposed according to the corresponding results. In addition, the Ni particles are dispersed on the Si substrate with the help of alkaline etching, which enables the lateral growth of Si nanowires on a Si substrate. This offers a simple and practical way of synthesizing and positioning the Si nanowires on a substrate.
A historical review of the development of verification and validation theories for simulation models
Authors: Durst Phillip J. , Anderson Derek T. , Bethel Cindy L.
Published: January 2017

Modeling and simulation (M&S) play a critical role in both engineering and basic research processes. Computer-based models have existed since the 1950s, and those early models have given way to the more complex computational and physics-based simulations used today. As such, a great deal of research has been done to establish what level of trust should be given to simulation outputs and how to verify and validate the models used in these simulations. This paper presents an overview of the theoretical work done to date defining formal definitions for, and methods of, verification and validation (V&V) of computer models. Simulation models are broken down into three broad categories: analytical and simulation models, computational and physics-based models, and simulations of autonomous systems, and the unique theories and methods developed to address V&V of these models are presented. This paper also presents the current problems in the theoretical field of V&V for models as simulations move from single system models and simulations to more complex simulation tools. In particular, this paper highlights the lack of agreed-upon methods for V&V of simulations of autonomous systems, such as an autonomous unmanned vehicles, and proposes some next steps needed to address this problem.
Adaptive forgetting factor OS-ELM and bootstrap for time series prediction
Authors: Liu Jingzhong
Published: January 2017

Online sequential extreme learning machine (OS-ELM) for single-hidden layer feedforward networks (SLFNs) is an effective machine learning algorithm. But OS-ELM has some underlying weaknesses of neglecting time series timeliness and being incapable to provide quantitative uncertainty for prediction. To overcome these shortcomings, a time series prediction method is presented based on the combination of OS-ELM with adaptive forgetting factor (AFF-OS-ELM) and bootstrap (B-AFF-OS-ELM). Firstly, adaptive forgetting factor is added into OS-ELM for adjusting the effective window length of training data during OS-ELM sequential learning phase. Secondly, the current bootstrap is developed to fit time series prediction online. Then associated with improved bootstrap, the proposed method can compute prediction interval as uncertainty information, meanwhile the improved bootstrap enhances prediction accuracy and stability of AFF-OS-ELM. Performances of B-AFF-OS-ELM are benchmarked with other traditional and improved OS-ELM on simulation and practical time series data. Results indicate the significant performances achieved by B-AFF-OS-ELM.
Exceptional solutions to the Painlevé VI equation associated with the generalized Jacobi weight
Authors: Lyu Shulin , Chen Yang
Published: January 2017

We consider the generalized Jacobi weight [Formula: see text], [Formula: see text]. As is shown in [D. Dai and L. Zhang, Painlevé VI and Henkel determinants for the generalized Jocobi weight, J. Phys. A: Math. Theor. 43 (2010), Article ID:055207, 14pp.], the corresponding Hankel determinant is the [Formula: see text]-function of a particular Painlevé VI. We present all the possible asymptotic expansions of the solution of the Painlevé VI equation near [Formula: see text] and [Formula: see text] for generic [Formula: see text]. For four special cases of [Formula: see text] which are related to the dimension of the Hankel determinant, we can find the exceptional solutions of the Painlevé VI equation according to the results of [A. Eremenko, A. Gabrielov and A. Hinkkanen, Exceptional solutions to the Painlevé VI equation, preprint (2016), arXiv:1602.04694 ], and thus give another characterization of the Hankel determinant.
Reducing the Complexity of Dataflow Graphs Using Slack-Based Merging
Authors: Ali Hazem Ismail , Stuijk Sander , Akesson Benny , Pinho Luís Miguel
Published: January 2017

There exist many dataflow applications with timing constraints that require real-time guarantees on safe execution without violating their deadlines. Extraction of timing parameters (offsets, deadlines, periods) from these applications enables the use of real-time scheduling and analysis techniques, and provides guarantees on satisfying timing constraints. However, existing extraction techniques require the transformation of the dataflow application from highly expressive dataflow computational models, for example, Synchronous Dataflow (SDF) and Cyclo-Static Dataflow (CSDF) to Homogeneous Synchronous Dataflow (HSDF). This transformation can lead to an exponential increase in the size of the application graph that significantly increases the runtime of the analysis.

In this article, we address this problem by proposing an offline heuristic algorithm called
slack-based merging
. The algorithm is a novel graph reduction technique that helps in speeding up the process of timing parameter extraction and finding a feasible real-time schedule, thereby reducing the overall design time of the real-time system. It uses two main concepts: (a) the difference between the worst-case execution time of the SDF graph’s firings and its timing constraints (slack) to merge firings together and generate a reduced-size HSDF graph, and (b) the novel concept of merging called
safe merge
, which is a merge operation that we formally prove cannot cause a live HSDF graph to deadlock. The results show that the reduced graph (1) respects the throughput and latency constraints of the original application graph and (2) typically speeds up the process of extracting timing parameters and finding a feasible real-time schedule for real-time dataflow applications. They also show that when the throughput constraint is relaxed with respect to the maximal throughput of the graph, the merging algorithm is able to achieve a larger reduction in graph size, which in turn results in a larger speedup of the real-time scheduling algorithms.
Specification Mining for Machine Improvisation with Formal Specifications
Authors: Valle Rafael , Donzé Alexandre , Fremont Daniel J. , Akkaya Ilge , Seshia Sanjit A. , Freed Adrian , Wessel David
Published: January 2017

We address the problem of mining musical specifications from a training set of songs and using these specifications in a machine improvisation system capable of generating improvisations imitating a given style of music. Our inspiration comes from
control improvisation
, which combines learning and synthesis from formal specifications. We mine specifications from symbolic musical data with musical and general usage patterns. We use the mined specifications to ensure that an improvised musical sequence satisfies desirable properties given a harmonic context and phrase structure. We present a specification mining strategy based on pattern graphs and apply it to the problem of supervising the improvisation of blues songs. We present an analysis of the mined specifications and compare the results of improvisations generated with and without specifications.
Scale & Cap
Authors: Hankendi Can , Coskun Ayse Kivilcim
Published: January 2017

As the number of cores per server node increases, designing multi-threaded applications has become essential to efficiently utilize the available hardware parallelism. Many application domains have started to adopt multi-threaded programming; thus, efficient management of multi-threaded applications has become a significant research problem. Efficient execution of multi-threaded workloads on cloud environments, where applications are often consolidated by means of virtualization, relies on understanding the multi-threaded specific characteristics of the applications. Furthermore, energy cost and power delivery limitations require data center server nodes to work under power caps, which bring additional challenges to runtime management of consolidated multi-threaded applications. This article proposes a dynamic resource allocation technique for consolidated multi-threaded applications for power-constrained environments. Our technique takes into account application characteristics specific to multi-threaded applications, such as power and performance scaling, to make resource distribution decisions at runtime to improve the overall performance, while accurately tracking dynamic power caps. We implement and evaluate our technique on state-of-the-art servers and show that the proposed technique improves the application performance by up to 21% under power caps compared to a default resource manager.
Characterizing and Adapting the Consistency-Latency Tradeoff in Distributed Key-Value Stores
Authors: Rahman Muntasir Raihan , Tseng Lewis , Nguyen Son , Gupta Indranil , Vaidya Nitin
Published: January 2017

The CAP theorem is a fundamental result that applies to distributed storage systems. In this article, we first present and prove two CAP-like impossibility theorems. To state these theorems, we present probabilistic models to characterize the three important elements of the CAP theorem: consistency (C), availability or latency (A), and partition tolerance (P). The theorems show the un-achievable envelope, that is, which combinations of the parameters of the three models make them impossible to achieve together. Next, we present the design of a class of systems called Probabilistic CAP (PCAP) that perform close to the envelope described by our theorems. In addition, these systems allow applications running on a single data center to specify either a latency Service Level Agreement (SLA) or a consistency SLA. The PCAP systems automatically adapt, in real time and under changing network conditions, to meet the SLA while optimizing the other C/A metric. We incorporate PCAP into two popular key-value stores: Apache Cassandra and Riak. Our experiments with these two deployments, under realistic workloads, reveal that the PCAP systems satisfactorily meets SLAs and perform close to the achievable envelope. We also extend PCAP from a single data center to multiple geo-distributed data centers.
Authentication Challenges in a Global Environment
Authors: Matsumoto Stephanos , Reischuk Raphael M. , Szalachowski Pawel , Kim Tiffany Hyun-Jin , Perrig Adrian
Published: January 2017

In this article, we address the problem of scaling authentication for naming, routing, and end-entity (EE) certification to a global environment in which authentication policies and users’ sets of trust roots vary widely. The current mechanisms for authenticating names (DNSSEC), routes (BGPSEC), and EE certificates (TLS) do not support a coexistence of authentication policies, affect the entire Internet when compromised, cannot update trust root information efficiently, and do not provide users with the ability to make flexible trust decisions. We propose the Scalable Authentication Infrastructure for Next-generation Trust (SAINT), which partitions the Internet into groups with common, local trust roots and isolates the effects of a compromised trust root. SAINT requires groups with direct routing connections to cross-sign each other for authentication purposes, allowing diverse authentication policies while keeping all entities’ authentication information globally discoverable. SAINT makes trust root management a central part of the network architecture, enabling trust root updates within seconds and allowing users to make flexible trust decisions. SAINT operates without a significant performance penalty and can be deployed alongside existing infrastructures.
Computational Sprinting
Authors: Zahedi Seyed Majid , Fan Songchun , Faw Matthew , Cole Elijah , Lee Benjamin C.
Published: January 2017

Computational sprinting is a class of mechanisms that boost performance but dissipate additional power. We describe a sprinting architecture in which many, independent chip multiprocessors share a power supply and sprints are constrained by the chips’ thermal limits and the rack’s power limits. Moreover, we present the computational sprinting game, a multi-agent perspective on managing sprints. Strategic agents decide whether to sprint based on application phases and system conditions. The game produces an equilibrium that improves task throughput for data analytics workloads by 4--6× over prior greedy heuristics and performs within 90% of an upper bound on throughput from a globally optimized policy.
Algorithmic Differentiation of Code with Multiple Context-Specific Activities
Authors: Hückelheim Jan Christian , Hascoët Laurent , Müller Jens-Dominik
Published: January 2017

Algorithmic differentiation (AD) by source-transformation is an established method for computing derivatives of computational algorithms. Static dataflow analysis is commonly used by AD tools to determine the set of
active
variables, that is, variables that are influenced by the program input in a differentiable way and have a differentiable influence on the program output. In this work, a context-sensitive static analysis combined with procedure cloning is used to generate specialised versions of differentiated procedures for each call site. This enables better detection and elimination of unused computations and memory storage, resulting in performance improvements of the generated code, in both forward- and reverse-mode AD. The implications of this
multi-activity AD
approach on the static analysis of an AD tool is shown using dataflow equations. The worst-case cost of multi-activity AD on the differentiation process is analysed and practical remedies to avoid running into this worst case are presented. The method was implemented in the AD tool Tapenade, and we present its application to a 3D unstructured compressible flow solver, for which we generate an adjoint solver that performs significantly faster when multi-activity AD is used.