bluuebunny/crossref_metadata_2025 huggingface dataset:
Fetal Doppler velocimetry and bronchopulmonary dysplasia risk among growth-restricted preterm infants: an observational study
Authors: Lio Alessandra , Rosati Paolo , Pastorino Roberta , Cota Francesco , Tana Milena , Tirone Chiara , Aurilia Claudia , Ricci Cinzia , Gambacorta Alessandro , Paladini Angela , Mappa Ilenia , Buongiorno Silvia , Zannoni Gian Franco , Romagnoli Costantino , Vento Giovanni
Published: July 2017

Objective

To investigate whether fetal growth restriction (FGR) diagnosis, based on pathological prenatal fetal Doppler velocimetry, is associated with bronchopulmonary dysplasia (BPD) independently of being small for gestational age (SGA) per se at birth among very preterm infants.

Design

Prospective, observational study. FGR was defined as failing fetal growth in utero and fetal Doppler velocimetry abnormalities.

Setting

Policlinico Universitario Agostino Gemelli, Roma, Italy.

Patients

Preterm newborns with gestational age ≤30 weeks and birth weight (BW) ≤1250 g.

Main outcome measures

Bronchopulmonary dysplasia.

Results

In the study period, 178 newborns were eligible for the study. Thirty-nine infants (22%) were considered fetal growth-restricted infants. Among the 154 survived babies at 36 weeks postmenstrual age, 12 out of 36 (33%) of the FGR group developed BPD versus 8 out of 118 (7%) of the NO-FGR group (p<0.001). BPD rate was sixfold higher among the SGA-FGR infants compared with the SGA-NO-FGR infants. In a multivariable model, FGR was significantly associated with BPD risk (OR 5.1, CI 1.4 to 18.8, p=0.01), independently from BW z-score that still remains a strong risk factor (OR 0.5, CI 0.3 to 0.9, p=0.01).

Conclusion

Among SGA preterm infants, BPD risk dramatically increases when placenta dysfunction is the surrounding cause of low BW. Antenatal fetal Doppler surveillance could be a useful tool for studying placenta wellness and predicting BPD risk among preterm babies. Further research is needed to better understand how FGR affects lung development.
Productivity of public hospitals in Nepal: a data envelopment analysis
Authors: Silwal Pushkar Raj , Ashton Toni
Published: July 2017

Objectives

Public hospitals in Nepal account for a major share of the total health budget. Therefore, questions are often asked about the performance of these hospitals. Existing measures of performance are limited to historical ratio analyses without any benchmarks. The objective of this study is to explore the trends in inputs, outputs and productivity changes in Nepalese public hospitals from 2011–2012 to 2013–2014.

Setting and participants

The study was conducted among 32 Nepalese public hospitals (23 district level and 9 higher level) for the three fiscal years from 2011–2012 to 2013–2014.

Outcome measures

First, basic ratio analyses were conducted for the input and output measures over the study years. Then, Malmquist productivity change scores were obtained using data envelopment analysis. Aggregated as well as separate analyses were conducted for district level and higher level hospitals.

Results

Real expenditures of the sampled hospitals declined over the 3-year period from an average of US$ 371 000 in year 1 to US$ 368 730 in year 2 and US$ 328680 in year 3. The average aggregated hospital outputs increased marginally from 8276 in 2011–2012 to 8613 in 2013–2014. The total factor productivity of the study hospitals declined by 6.9% annually from 2011–2012 to 2013–2014. Of the total 32 hospitals, productivity increased in only 12 (37.5%) hospitals and declined in the remaining 20 hospitals. The total factor productivity loss was influenced by a decline in technology change, despite an increase in efficiency.

Conclusions

In general, productivity of the study hospitals declined over the study period. Availability and accessibility of accurate, detailed and consistent measures of hospital inputs and outputs is a major challenge for this type of analysis.
Sequence analysis to assess labour market participation following vocational rehabilitation: an observational study among patients sick-listed with low back pain from a randomised clinical trial in Denmark
Authors: Lindholdt Louise , Labriola Merete , Nielsen Claus Vinther , Horsbøl Trine Allerslev , Lund Thomas
Published: July 2017

Introduction

The return-to-work (RTW) process after long-term sickness absence is often complex and long and implies multiple shifts between different labour market states for the absentee. Standard methods for examining RTW research typically rely on the analysis of one outcome measure at a time, which will not capture the many possible states and transitions the absentee can go through. The purpose of this study was to explore the potential added value of sequence analysis in supplement to standard regression analysis of a multidisciplinary RTW intervention among patients with low back pain (LBP).

Methods

The study population consisted of 160 patients randomly allocated to either a hospital-based brief or a multidisciplinary intervention. Data on labour market participation following intervention were obtained from a national register and analysed in two ways: as a binary outcome expressed as active or passive relief at a 1-year follow-up and as four different categories for labour market participation. Logistic regression and sequence analysis were performed.

Results

The logistic regression analysis showed no difference in labour market participation for patients in the two groups after 1 year. Applying sequence analysis showed differences in subsequent labour market participation after 2 years after baseline in favour of the brief intervention group versus the multidisciplinary intervention group.

Conclusion

The study indicated that sequence analysis could provide added analytical value as a supplement to traditional regression analysis in prospective studies of RTW among patients with LBP.
Relationship between receipt of substitutable for-fee vaccines and completion of the expanded programme on immunisation: a cross-sectional study in Fujian, China
Authors: Wu Jiang-Nan , Li Da-Jin , Zhou Yong , Du Mei-Rong , Piao Hai-Lan
Published: July 2017

Objective

The aim of this study was to evaluate the relationship between receipt of the substitutable-for-fee vaccines (SFV) and completion of the expanded programme on immunisation (EPI).

Design and settings

A cross-sectional study was conducted in Fujian province, China.

Participants

Children who were born from 1 September 2009 to 31 August 2011, and who had been residing in the township for at least 3 months, were randomly recruited from 34 townships.

Main outcomes measures

Outcomes were completion rate of the EPI and coverage rate of the SFV.

Results

The study included 1428 children, of whom 1350 (94.5%) finished the EPI and 282 (19.7%) received at least one dose of the SFV. Administration of the SFV was associated with an increased likelihood of completing the EPI (OR=3.2, 95% CI 1.3 to 7.6 in the total sample and OR=4.0, 95% CI 1.7 to 9.6 in the subsample of children in regions with the SFV accessibility). The impact of the SFV administration on completion of the EPI was larger among children whose parents have junior school education or less (97.8% and 97.9% vs 92.5% and 91.9%, both p<0.001) and among those with a timely hepatitis B vaccine first dose (98.5% vs 94.0%, p<0.001).

Conclusions

Receipt of SFV is associated with increased likelihood of completion of the EPI in Fujian, China.
Accelerated enhancedRecovery followingMinimallyInvasive colorectal cancer surgery (RecoverMI): a study protocol for a novel randomised controlled trial
Authors: Price Brandee A , Bednarski Brian K , You Y Nancy , Manandhar Meryna , Dean E Michelle , Alawadi Zeinab M , Bryce Speer B , Gottumukkala Vijaya , Weldon Marla , Massey Robert L , Wang Xuemei , Qiao Wei , Chang George J
Published: July 2017

Introduction

Definitive treatment of localised colorectal cancer involves surgical resection of the primary tumour. Short-stay colectomies (eg, 23-hours) would have important implications for optimising the efficiency of inpatient care with reduced resource utilisation while improving the overall recovery experience with earlier return to normalcy. It could permit surgical treatment of colorectal cancer in a wider variety of settings, including hospital-based ambulatory surgery environments. While a few studies have shown that discharge within the first 24 hours after minimally invasive colectomy is possible, the safety, feasibility and patient acceptability of a protocol for short-stay colectomy for colorectal cancer have not previously been evaluated in a prospective randomised study. Moreover, given the potential for some patients to experience a delay in recovery of bowel function after colectomy, close outpatient monitoring may be necessary to ensure safe implementation.

Methods and analysis

In order to address this gap, we propose a prospective randomised trial of accelerated enhancedRecovery followingMinimallyInvasive colorectal cancer surgery (RecoverMI) that leverages the combination of minimally invasive surgery with enhanced recovery protocols and early coordinated outpatient remote televideo conferencing technology (TeleRecovery) to improve postoperative patien-provider communication, enhance postoperative treatment navigation and optimise postdischarge care. We hypothesise that RecoverMI can be safely incorporated into multidisciplinary practice to improve patient outcomes and reduce the overall 30-day duration of hospitalisation while preserving the quality of the patient experience.

Ethics and dissemination

RecoverMIhas received institutional review board approval and funding from the American Society of Colorectal Surgeons (ASCRS; LPG103). Results from RecoverMI will be published in a peer-reviewed publication and be used to inform a multisite trial.

Trial registration number

NCT02613728; Pre-results.
Gait outcomes of older adults receiving subacute hospital rehabilitation following orthopaedic trauma: a longitudinal cohort study
Authors: Mathew Saira A , Varghese Paul , Kuys Suzanne S , Heesch Kristiann C , McPhail Steven M
Published: July 2017

Objectives

This study aimed to describe gait speed at admission and discharge from inpatient hospital rehabilitation among older adults recovering from orthopaedic trauma and factors associated with gait speed performance and discharge destination.

Design

A longitudinal cohort study was conducted.

Setting

Australian tertiary hospital subacute rehabilitation wards.

Participants

Patients aged ≥60 years recovering from orthopaedic trauma (n=746, 71% female) were eligible for inclusion.

Interventions

Usual care (multidisciplinary inpatient hospital rehabilitation).

Primary and secondary outcome measures

Gait speed was assessed using the timed 10 m walk test. The proportion of patients exceeding a minimum gait speed threshold indicator (a priori 0.8 m/s) of community ambulation ability was calculated. Generalised linear models were used to examine associations between patient and clinical factors with gait speed performance and being discharged to a residential aged care facility.

Results

At discharge, 18% of patients (n=135) exceeded the 0.8 m/s threshold indicator for community ambulation ability. Faster gait speed at discharge was found to be associated with being male (B=0.44, 95% CI −0.01 to 0.88), admitted with pelvic (B=0.76, 95% CI 0.15 to 1.38) or multiple fractures (B=1.13, 95% CI 0.25 to 2.02) (vs hip fracture), using no mobility aids (B=−0.94, 95% CI −1.89 to 0.01) and walking at a faster gait speed at admission (B=5.77, 95% CI 5.04 to 6.51). Factors associated with being discharged to residential aged care included older age (OR 1.07, 95% CI 1.04 to 1.11), longer length of stay (OR 1.02, 95% CI 1.01 to 1.03), having an upper limb fracture (vs hip fracture) (OR 2.80, 95% CI 1.32 to 5.94) and lower Functional Independence Measure cognitive score (OR 0.90, 95% CI 0.87 to 0.93).

Conclusions

Patients with a range of injury types, not only those presenting to hospital with hip fractures, are being discharged with slow gait speeds that are indicative of limited functional mobility and a high risk of further adverse health events.
Risk of sarcoidosis and seropositive rheumatoid arthritis from occupational silica exposure in Swedish iron foundries: a retrospective cohort study
Authors: Vihlborg Per , Bryngelsson Ing-Liss , Andersson Lena , Graff Pål
Published: July 2017

Objective

To study the impact of occupational silica exposure on the incidence rates of sarcoidosis and rheumatoid arthritis (RA) in a cohort of exposed workers in Swedish iron foundries.

Design

The prevalence of sarcoidosis and RA in a cohort of silica exposed workers was compared with the prevalence in the general Swedish population in this register study. A mixed model was used to calculate silica exposure, and individual silica exposures were used to compute dose responses.

Setting

Personnel records from 10 iron foundries were used to identify workers whose employment began before 2005 which was then linked to the national non-primary outpatient visits register.

Participants

The final cohort consisted of 2187 silica-exposed male workers who had been employed for at least 1 year and were still alive without having emigrated when the follow-up study began. The cohort’s employment period covers 23 807 person-years at risk.

Main outcome

The presented results indicate that moderate to high levels of silica exposure increase risks for sarcoidosis and seropositive RA.

Results

Mean levels of airborne silica dust in the foundries decreased significantly between the 1970s and 2000s. Incidence rates of sarcoidosis (3.94; 95% CI 1.07 to 10.08) and seropositive RA (2.59; 95% CI 1.24 to 4.76) were significantly higher among highly exposed individuals.

Conclusion

Our results reveal increased risks for sarcoidosis and seropositive RA among individuals with high exposure to silica dust (>0.048 mg/m3) compared with non-exposed and less-exposed groups.
Comparative safety of antiepileptic drugs for neurological development in children exposed during pregnancy and breast feeding: a systematic review and network meta-analysis
Authors: Veroniki Areti Angeliki , Rios Patricia , Cogo Elise , Straus Sharon E , Finkelstein Yaron , Kealey Ryan , Reynen Emily , Soobiah Charlene , Thavorn Kednapa , Hutton Brian , Hemmelgarn Brenda R , Yazdi Fatemeh , D'Souza Jennifer , MacDonald Heather , Tricco Andrea C
Published: July 2017

Objectives

Compare the safety of antiepileptic drugs (AEDs) on neurodevelopment of infants/children exposed in utero or during breast feeding.

Design and setting

Systematic review and Bayesian random-effects network meta-analysis (NMA). MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials were searched until 27 April 2017. Screening, data abstraction and quality appraisal were completed in duplicate by independent reviewers.

Participants

29 cohort studies including 5100 infants/children.

Interventions

Monotherapy and polytherapy AEDs including first-generation (carbamazepine, clobazam, clonazepam, ethosuximide, phenobarbital, phenytoin, primidone, valproate) and newer-generation (gabapentin, lamotrigine, levetiracetam, oxcarbazepine, topiramate, vigabatrin) AEDs. Epileptic women who did not receive AEDs during pregnancy or breast feeding served as the control group.

Primary and secondary outcome measures

Cognitive developmental delay and autism/dyspraxia were primary outcomes. Attention-deficit hyperactivity disorder, language delay, neonatal seizures, psychomotor developmental delay and social impairment were secondary outcomes.

Results

The NMA on cognitive developmental delay (11 cohort studies, 933 children, 18 treatments) suggested that among all AEDs only valproate was statistically significantly associated with more children experiencing cognitive developmental delay compared with control (OR=7.40, 95% credible interval (CrI) 3.00 to 18.46). The NMA on autism (5 cohort studies, 2551 children, 12 treatments) suggested that oxcarbazepine (OR 13.51, CrI 1.28 to 221.40), valproate (OR 17.29, 95% CrI 2.40 to 217.60), lamotrigine (OR 8.88, CrI 1.28 to 112.00) and lamotrigine+valproate (OR 132.70, CrI 7.41 to 3851.00) were associated with significantly greater odds of developing autism compared with control. The NMA on psychomotor developmental delay (11 cohort studies, 1145 children, 18 treatments) found that valproate (OR 4.16, CrI 2.04 to 8.75) and carbamazepine+phenobarbital+valproate (OR 19.12, CrI 1.49 to 337.50) were associated with significantly greater odds of psychomotor delay compared with control.

Conclusions

Valproate alone or combined with another AED is associated with the greatest odds of adverse neurodevelopmental outcomes compared with control. Oxcarbazepine and lamotrigine were associated with increased occurrence of autism. Counselling is advised for women considering pregnancy to tailor the safest regimen.

Trial registration number

PROSPERO database (CRD42014008925).
Evaluation by various methods of the physiological mechanism of a high-flow nasal cannula (HFNC) in healthy volunteers
Authors: Okuda Miyuki , Tanaka Nobuya , Naito Kazuyuki , Kumada Takao , Fukuda Koji , Kato Yuto , Kido Yuto , Okuda Yutaro , Nohara Ryuji
Published: July 2017

Introduction

Several reports have described the usefulness of a high-flow nasal cannula (HFNC). However, the physiological mechanisms of this system are unclear. In the current study, various methods were used to investigate the physiological mechanisms of an HFNC in healthy volunteers.

Methods

The physiological mechanisms of the constant-flow and constant-pressure models of HFNC were studied in 10 healthy volunteers by the oesophageal balloon method, the electrical impedance method and the forced oscillation technique (FOT).

Results

The tidal volume (TV) increased markedly during HFNC (off, 30 L/min, 50 L/min: 685.6±236.5 mL, 929.8±434.7 mL, 968.8±451.1 mL). The end-inspiratory oesophageal pressure (EIOP) was not significantly different, but there was a tendency for it to decrease. HFNC 30 L/min and 50 L/min, the increment in TV and the difference in EIOP showed strong negative correlations (p=0.0025, 0.003). The end-expiratory oesophageal pressure (EEOP) increased. The respiratory system reactance at 5 Hz (X5) by FOT decreased significantly. There was a flow rate-dependent EEOP increase, and the positive end-expiratory pressure (PEEP) effect of HFNC was confirmed. There was a correlation between the difference in X5 and the difference in EEOP during HFNC 30 L/min and 50 L/min, with correlation coefficients of 0.534 and 0.404 (p=0.112, 0.281). The amount of change in EEOP and the fluctuation in X5 were positively correlated.

Conclusions

The PEEP effect of HFNC was confirmed by the electrical impedance method and FOT. The increment in TV and the difference in EIOP of HFNC showed strong negative correlations.
A national quitline service and its promotion in the mass media: modelling the health gain, health equity and cost–utility
Authors: Nghiem Nhung , Cleghorn Christine L , Leung William , Nair Nisha , Deen Frederieke S van der , Blakely Tony , Wilson Nick
Published: July 2017

Background

Mass media campaigns and quitlines are both important distinct components of tobacco control programmes around the world. But when used as an integrated package, the effectiveness and cost-effectiveness are not well described. We therefore aimed to estimate the health gain, health equity impacts and cost–utility of the package of a national quitline service and its promotion in the mass media.

Methods

We adapted an established Markov and multistate life-table macro-simulation model. The population was all New Zealand adults in 2011. Effect sizes and intervention costs were based on past New Zealand quitline data. Health system costs were from a national data set linking individual health events to costs.

Results

The 1-year operation of the existing intervention package of mass media promotion and quitline service was found to be net cost saving to the health sector for all age groups, sexes and ethnic groups (saving $NZ84 million; 95%uncertainty interval 60–115 million in the base-case model). It also produced greater per capita health gains for Māori (indigenous) than non-Māori (2.2 vs 0.73 quality-adjusted life-years (QALYs) per 1000 population, respectively). The net cost saving of the intervention was maintained in all sensitivity and scenario analyses for example at a discount rate of 6% and when the intervention effect size was quartered (given the possibility of residual confounding in our estimates of smoking cessation). Running the intervention for 20 years would generate an estimated 54 000 QALYs and $NZ1.10 billion (US$0.74 billion) in cost savings.

Conclusions

The package of a quitline service and its promotion in the mass media appears to be an effective means to generate health gain, address health inequalities and save health system costs. Nevertheless, the role of this intervention needs to be compared with other tobacco control and health sector interventions, some of which may be even more cost saving.
My week: Jenny Jaffe
Authors: Jaffe Jenny
Published: July 2017

Jenny Jaffe is a veterinarian who works on disease risk analysis and health surveillance at the Zoological Society of London. Here, she describes a recent week
Using metagenomics to show the efficacy of forest restoration in the New Jersey Pine Barrens
Authors: Eaton William D. , Shokralla Shadi , McGee Kathleen M. , Hajibabaei Mehrdad
Published: July 2017

The Franklin Parker Preserve within the New Jersey Pine Barrens contains 5000 acres of wetlands habitat, including old-growth Atlantic white cedar (or AWC; Chamaecyparis thyoides) swamps, cranberry bogs, and former cranberry bogs undergoing restoration into AWC forests. This study showed that the C-use efficiency was greater in the old-growth AWC soils than in soils from 8-year-old mid-stage restored AWC stands, which were greater than found in soil from 4-year-old AWC stands—the latter two stands being restored from long-term cranberry bogs. A metagenomic analysis of eDNA extracted from these soils showed that the C-cycle trends were associated with increases in the relative numbers of DNA sequences from several copiotrophic bacterial groups (Bacteroidetes and Proteobacteria), complex C-decomposing fungal groups (Sordiomycetes, Mortierellales, and Thelephorales), and collembolan and formicid invertebrates. All groups are indicators of successionally more advanced soils, and critical for soil C-cycle activities. These data suggest that the restoration activities studied are enhancing critical guilds of soil biota, and increasing C-use efficiency in the soils of restored habitats, and that the use of metagenomic analysis of soil eDNA can be used in the development of assessment models for soil recovery of wetlands following restoration.
Exploring the potential of gametic reconstruction of parental genotypes by F1hybrids as a bridge for rapid introgression
Authors: Cannon Charles H. , Scher C. Lane
Published: July 2017

Interspecific hybridization and genetic introgression are commonly observed in natural populations of many species, especially trees. Among oaks, gene flow between closely related species has been well documented. And yet, hybridization does not lead to a “melting pot”, i.e., the homogenization of phenotypic traits. Here, we explore how the combination of several common reproductive and genomic traits could create an avenue for interspecific gene flow that partially explains this apparent paradox. During meiosis, F1hybrids will produce approximately (½)n“reconstructed” parental gametes, where n equals the number of chromosomes. Crossing over would introduce a small amount of introgressive material. The resulting parental-type gametophytes would probably possess a similar fertilization advantage as conspecific pollen. The resulting “backcross” would actually be the genetic equivalent of a conspecific out-cross, with a small amount of heterospecific DNA captured through crossing over. Even with detailed genomic analysis, the resulting offspring would not appear to be a backcross. This avenue for rapid introgression between species through the F1hybrid will be viable for organisms that meet certain conditions: low base chromosome number, conserved genomic structure and size, production of billions of gametes/gametophytes during each reproductive event, and conspecific fertilization advantage.
Spatial organization of fibroblast and spermatocyte nuclei with different B-chromosome content in Korean field mouse, Apodemus peninsulae (Rodentia, Muridae)
Authors: Karamysheva Tatyana V. , Torgasheva Anna A. , Yefremov Yaroslav R. , Bogomolov Anton G. , Liehr Thomas , Borodin Pavel M. , Rubtsov Nikolay B.
Published: July 2017

Korean field mouse (Apodemus peninsulae) shows a wide variation in the number of B chromosomes composed of constitutive heterochromatin. For this reason, it provides a good model to study the influence of the number of centromeres and amount of heterochromatin on spatial organization of interphase nuclei. We analyzed the three-dimensional organization of fibroblast and spermatocyte nuclei of the field mice carrying a different number of B chromosomes using laser scanning microscopy and 3D fluorescence in situ hybridization. We detected a co-localization of the B chromosomes with constitutive heterochromatin of the chromosomes of the basic set. We showed a non-random distribution of B chromosomes in the spermatocyte nuclei. Unpaired B chromosomes showed a tendency to occur in the compartment formed by the unpaired part of the XY bivalent.
A Predator–Prey Model with Prey Population Guided Anti-Predator Behavior
Authors: Sun Xiaodan , Li Yingping , Xiao Yanni
Published: July 2017

We consider a predator–prey system with prey population guided anti-predator behavior, in which anti-predator behaviors happen only when the population size of the prey is greater than a threshold. We investigate the rich dynamics of the proposed piecewise model as well as both subsystems without and with nonlinear functional response. In particular, the subsystem with anti-predator behaviors exhibits rich dynamical behaviors including saddle-node bifurcation, Hopf bifurcation, Bogdanov–Takens bifurcation and homoclinic bifurcation. Further, besides the dynamical properties of subsystems the piecewise system shows some new complicated dynamical behaviors as the threshold value varies, including unstable limit cycle, semistable limit cycle, bistability of equilibrium and limit cycle, and tristability of three equilibria. From the switching system we can conclude that a great anti-predator rate induces the prey population to persist more likely, but whether the prey and predator populations coexist depends further on the threshold that triggers anti-predator behavior. Especially, a large threshold not only makes coexistence of the prey and predator populations as an equilibrium more likely, but also damps the predator–prey oscillations.
On the Existence of Limit Cycles and Relaxation Oscillations in a 3D van der Pol-like Memristor Oscillator
Authors: Messias Marcelo , Maciel Anderson L.
Published: July 2017

We study a van der Pol-like memristor oscillator, obtained by substituting a Chua’s diode with an active controlled memristor in a van der Pol oscillator with Chua’s diode. The mathematical model for the studied circuit is given by a three-dimensional piecewise linear system of ordinary differential equations, depending on five parameters. We show that this system has a line of equilibria given by the [Formula: see text]-axis and the phase space [Formula: see text] is foliated by invariant planes transverse to this line, which implies that the dynamics is essentially two-dimensional. We also show that in each of these invariant planes may occur limit cycles and relaxation oscillations (that is, nonsinusoidal repetitive (periodic) solutions), depending on the parameter values. Hence, the oscillator studied here, constructed with a memristor, is also a relaxation oscillator, as the original van der Pol oscillator, although with a main difference: in the case of the memristor oscillator, an infinity of oscillations are produced, one in each invariant plane, depending on the initial condition considered. We also give conditions for the nonexistence of oscillations, depending on the position of the invariant planes in the phase space.
A Double Perturbation Method for Reducing Dynamical Degradation of the Digital Baker Map
Authors: Liu Lingfeng , Lin Jun , Miao Suoxia , Liu Bocheng
Published: July 2017

The digital Baker map is widely used in different kinds of cryptosystems, especially for image encryption. However, any chaotic map which is realized on the finite precision device (e.g. computer) will suffer from dynamical degradation, which refers to short cycle lengths, low complexity and strong correlations. In this paper, a novel double perturbation method is proposed for reducing the dynamical degradation of the digital Baker map. Both state variables and system parameters are perturbed by the digital logistic map. Numerical experiments show that the perturbed Baker map can achieve good statistical and cryptographic properties. Furthermore, a new image encryption algorithm is provided as a simple application. With a rather simple algorithm, the encrypted image can achieve high security, which is competitive to the recently proposed image encryption algorithms.
Global Hopf Bifurcation for a Predator–Prey System with Three Delays
Authors: Jiang Zhichao , Wang Lin
Published: July 2017

In this paper, a delayed predator–prey model is considered. The existence and stability of the positive equilibrium are investigated by choosing the delay [Formula: see text] as a bifurcation parameter. We see that Hopf bifurcation can occur as [Formula: see text] crosses some critical values. The direction of the Hopf bifurcations and the stability of the bifurcation periodic solutions are also determined by using the center manifold and normal form theory. Furthermore, based on the global Hopf bifurcation theorem for general function differential equations, which was established by J. Wu using fixed point theorem and degree theory methods, the existence of global Hopf bifurcation is investigated. Finally, numerical simulations to support the analytical conclusions are carried out.
Approximations of the Homoclinic Orbits Near a Double-Zero Bifurcation with Symmetry of Order Two
Authors: Rocşoreanu Carmen , Sterpu Mihaela
Published: July 2017

The two-dimensional system of differential equations corresponding to the normal form of the double-zero bifurcation with symmetry of order two is considered. This is a codimension two bifurcation. The associated dynamical system exhibits, among others, a homoclinic bifurcation. In this paper, we obtain second order approximations both for the curve of parametric values of homoclinic bifurcation and for the homoclinic orbits. To perform this task, we reduce first the normal form to a perturbed Hamiltonian system, using a blow-up technique. Then, by means of a perturbation method, we determine explicit first and second order approximations of the homoclinic orbits. The solutions obtained theoretically are compared with those obtained numerically for several cases. Finally, an application of the obtained results is presented.
Dynamics and Physiological Roles of Stochastic Firing Patterns Near Bifurcation Points
Authors: Jia Bing , Gu Huaguang
Published: July 2017

Different stochastic neural firing patterns or rhythms that appeared near polarization or depolarization resting states were observed in biological experiments on three nervous systems, and closely matched those simulated near bifurcation points between stable equilibrium point and limit cycle in a theoretical model with noise. The distinct dynamics of spike trains and interspike interval histogram (ISIH) of these stochastic rhythms were identified and found to build a relationship to the coexisting behaviors or fixed firing frequency of four different types of bifurcations. Furthermore, noise evokes coherence resonances near bifurcation points and plays important roles in enhancing information. The stochastic rhythms corresponding to Hopf bifurcation points with fixed firing frequency exhibited stronger coherence degree and a sharper peak in the power spectrum of the spike trains than those corresponding to saddle-node bifurcation points without fixed firing frequency. Moreover, the stochastic firing patterns changed to a depolarization resting state as the extracellular potassium concentration increased for the injured nerve fiber related to pathological pain or static blood pressure level increased for aortic depressor nerve fiber, and firing frequency decreased, which were different from the physiological viewpoint that firing frequency increased with increasing pressure level or potassium concentration. This shows that rhythms or firing patterns can reflect pressure or ion concentration information related to pathological pain information. Our results present the dynamics of stochastic firing patterns near bifurcation points, which are helpful for the identification of both dynamics and physiological roles of complex neural firing patterns or rhythms, and the roles of noise.
AGGREGATION OF CRYSTALLINE COPPER SULPHATE SALT IN A GELATIN MEDIUM
Authors: BHATTACHARYYA SUBARNAREKHA , ROY BISWAJIT , TARAFDAR SUJATA
Published: July 2017

A drying droplet changes its morphological pattern depending upon complex pattern forming system. To control the distribution of solute particles in a droplet during drying is an important aspect in many scientific and industrial purposes. In this work, with the help of optical microscopy, we study characteristic patterns generated in dried drops of colloidal copper sulphate (CuSO[Formula: see text][Formula: see text]5H2O) solution on surface of glass. At lower concentration of salt solution the growth pattern follows a monofractal structure whereas at higher concentration, the self-assembled pattern gradually gets disappeared. Calculating the fractal dimension (FD) of the generated patterns by box counting method with help of imageJ, it is observed that the patterns resemble DLA structure through a specific range of concentration of the salt solution.
Inside fluids
Authors: Chern Albert , Knöppel Felix , Pinkall Ulrich , Schröder Peter
Published: July 2017

Clebsch maps encode velocity fields through functions. These functions contain valuable information about the velocity field. For example, closed integral curves of the associated vorticity field are level lines of the vorticity Clebsch map. This makes Clebsch maps useful for visualization and fluid dynamics analysis. Additionally they can be used in the context of simulations to enhance flows through the introduction of subgrid vorticity. In this paper we study
spherical
Clebsch maps, which are particularly attractive. Elucidating their geometric structure, we show that such maps can be found as minimizers of a non-linear Dirichlet energy. To illustrate our approach we use a number of benchmark problems and apply it to numerically given flow fields. Code and a video can be found in the ACM Digital Library.
Sequential line search for efficient visual design optimization by crowds
Authors: Koyama Yuki , Sato Issei , Sakamoto Daisuke , Igarashi Takeo
Published: July 2017

Parameter tweaking is a common task in various design scenarios. For example, in color enhancement of photographs, designers tweak multiple parameters such as "brightness" and "contrast" to obtain the best visual impression. Adjusting one parameter is easy; however, if there are multiple correlated parameters, the task becomes much more complex, requiring many trials and a large cognitive load. To address this problem, we present a novel extension of
Bayesian optimization
techniques, where the system decomposes the entire parameter tweaking task into a sequence of one-dimensional
line search
queries that are easy for human to perform by manipulating a single slider. In addition, we present a novel concept called
crowd-powered visual design optimizer
, which queries crowd workers, and provide a working implementation of this concept. Our
single-slider manipulation
microtask design for crowdsourcing accelerates the convergence of the optimization relative to existing comparison-based microtask designs. We applied our framework to two different design domains: photo color enhancement and material BRDF design, and thereby showed its applicability to various design domains.
An efficient and practical near and far field fur reflectance model
Authors: Yan Ling-Qi , Jensen Henrik Wann , Ramamoorthi Ravi
Published: July 2017

Physically-based fur rendering is difficult. Recently, structural differences between hair and fur fibers have been revealed by Yan et al. (2015), who showed that fur fibers have an inner scattering medulla, and developed a double cylinder model. However, fur rendering is still complicated due to the complex scattering paths through the medulla. We develop a number of optimizations that improve efficiency and generality without compromising accuracy, leading to a practical fur reflectance model. We also propose a key contribution to support both near and far-field rendering, and allow smooth transitions between them.

Specifically, we derive a compact BCSDF model for fur reflectance with only 5 lobes. Our model unifies hair and fur rendering, making it easy to implement within standard hair rendering software, since we keep the traditional
R
,
TT
, and
TRT
lobes in hair, and only add two extensions to scattered lobes,

TT
s

and

TRT
s

. Moreover, we introduce a compression scheme using tensor decomposition to dramatically reduce the precomputed data storage for scattered lobes to only 150 KB, with minimal loss of accuracy. By exploiting piecewise analytic integration, our method further enables a multi-scale rendering scheme that transitions between near and far field rendering smoothly and efficiently for the first time, leading to 6 -- 8× speed up over previous work.
Multi-scale vorticle fluids
Authors: Angelidis Alexis
Published: July 2017

We present a multi-scale method for simulating incompressible gases in 3-dimensions with resolution variation suitable for perspective cameras and regions of importance. The dynamics is derived from the vorticity equation. Lagrangian particles are created, modified and deleted in a manner that handles advection with buoyancy and viscosity. Boundaries and deformable object collisions are modeled with the source and doublet panel method. Our acceleration structure is based on the FMM (Fast Multipole Method), but with a varying size to account for non-uniform sampling. Because the dynamics of our method is voxel free, we can freely specify the voxel resolution of the output density and velocity while keeping the main shapes and timing.
Patch-based optimization for image-based texture mapping
Authors: Bi Sai , Kalantari Nima Khademi , Ramamoorthi Ravi
Published: July 2017

Image-based texture mapping is a common way of producing texture maps for geometric models of real-world objects. Although a high-quality texture map can be easily computed for accurate geometry and calibrated cameras, the quality of texture map degrades significantly in the presence of inaccuracies. In this paper, we address this problem by proposing a novel global patch-based optimization system to synthesize the aligned images. Specifically, we use patch-based synthesis to reconstruct a set of photometrically-consistent aligned images by drawing information from the source images. Our optimization system is simple, flexible, and more suitable for correcting large misalignments than other techniques such as local warping. To solve the optimization, we propose a two-step approach which involves patch search and vote, and reconstruction. Experimental results show that our approach can produce high-quality texture maps better than existing techniques for objects scanned by consumer depth cameras such as Intel RealSense. Moreover, we demonstrate that our system can be used for texture editing tasks such as hole-filling and reshuffling as well as multiview camouflage.
Convolutional neural networks on surfaces via seamless toric covers
Authors: Maron Haggai , Galun Meirav , Aigerman Noam , Trope Miri , Dym Nadav , Yumer Ersin , Kim Vladimir G. , Lipman Yaron
Published: July 2017

The recent success of convolutional neural networks (CNNs) for image processing tasks is inspiring research efforts attempting to achieve similar success for geometric tasks. One of the main challenges in applying CNNs to surfaces is defining a natural convolution operator on surfaces.

In this paper we present a method for applying deep learning to sphere-type shapes using a global seamless parameterization to a planar flat-torus, for which the convolution operator is well defined. As a result, the standard deep learning framework can be readily applied for learning semantic, high-level properties of the shape. An indication of our success in bridging the gap between images and surfaces is the fact that our algorithm succeeds in learning semantic information from an input of raw low-dimensional feature vectors.

We demonstrate the usefulness of our approach by presenting two applications: human body segmentation, and automatic landmark detection on anatomical surfaces. We show that our algorithm compares favorably with competing geometric deep-learning algorithms for segmentation tasks, and is able to produce meaningful correspondences on anatomical surfaces where hand-crafted features are bound to fail.
3DTV at home
Authors: Kellnhofer Petr , Didyk Piotr , Wang Szu-Po , Sitthi-Amorn Pitchaya , Freeman William , Durand Fredo , Matusik Wojciech
Published: July 2017

Stereoscopic 3D (S3D) movies have become widely popular in the movie theaters, but the adoption of S3D at home is low even though most TV sets support S3D. It is widely believed that S3D with glasses is not the right approach for the home. A much more appealing approach is to use automulti-scopic displays that provide a glasses-free 3D experience to multiple viewers. A technical challenge is the lack of native multiview content that is required to deliver a proper view of the scene for every viewpoint. Our approach takes advantage of the abundance of stereoscopic 3D movies. We propose a real-time system that can convert stereoscopic video to a high-quality multiview video that can be directly fed to automultiscopic displays. Our algorithm uses a wavelet-based decomposition of stereoscopic images with per-wavelet disparity estimation. A key to our solution lies in combining Lagrangian and Eulerian approaches for both the disparity estimation and novel view synthesis, which leverages the complementary advantages of both techniques. The solution preserves all the features of Eulerian methods, e.g., subpixel accuracy, high performance, robustness to ambiguous depth cases, and easy integration of inter-view aliasing while maintaining the advantages of Lagrangian approaches, e.g., robustness to large disparities and possibility of performing non-trivial disparity manipulations through both view extrapolation and interpolation. The method achieves real-time performance on current GPUs. Its design also enables an easy hardware implementation that is demonstrated using a field-programmable gate array. We analyze the visual quality and robustness of our technique on a number of synthetic and real-world examples. We also perform a user experiment which demonstrates benefits of the technique when compared to existing solutions.
A practical extension to microfacet theory for the modeling of varying iridescence
Authors: Belcour Laurent , Barla Pascal
Published: July 2017

In this work, we introduce an extension to microfacet theory for the rendering of iridescent effects caused by thin-films of varying thickness (such as oil, grease, alcohols, etc) on top of an arbitrarily rough base layer. Our material model is the first to produce a consistent appearance between tristimulus (e.g., RGB) and spectral rendering engines by analytically pre-integrating its spectral response. The proposed extension works with any microfacet-based model: not only on reflection over dielectrics or conductors, but also on transmission through dielectrics. We adapt its evaluation to work in multi-scale rendering contexts, and we expose parameters enabling artistic control over iridescent appearance. The overhead compared to using the classic Fresnel reflectance or transmittance terms remains reasonable enough for practical uses in production.
A two-scale microfacet reflectance model combining reflection and diffraction
Authors: Holzschuch Nicolas , Pacanowski Romain
Published: July 2017

Adequate reflectance models are essential for the production of photorealistic images. Microfacet reflectance models predict the appearance of a material at the macroscopic level based on microscopic surface details. They provide a good match with measured reflectance in some cases, but not always. This discrepancy between the behavior predicted by microfacet models and the observed behavior has puzzled researchers for a long time. In this paper, we show that diffraction effects in the micro-geometry provide a plausible explanation. We describe a two-scale reflectance model, separating between geometry details much larger than wavelength and those of size comparable to wavelength. The former model results in the standard Cook-Torrance model. The latter model is responsible for diffraction effects. Diffraction effects at the smaller scale are convolved by the micro-geometry normal distribution. The resulting two-scale model provides a very good approximation to measured reflectances.
Power diagrams and sparse paged grids for high resolution adaptive liquids
Authors: Aanjaneya Mridul , Gao Ming , Liu Haixiang , Batty Christopher , Sifakis Eftychios
Published: July 2017

We present an efficient and scalable octree-inspired fluid simulation framework with the flexibility to leverage adaptivity in any part of the computational domain, even when resolution transitions reach the free surface. Our methodology ensures symmetry, definiteness and second order accuracy of the discrete Poisson operator, and eliminates numerical and visual artifacts of prior octree schemes. This is achieved by adapting the operators acting on the octree's simulation variables to reflect the structure and connectivity of a
power diagram
, which recovers primal-dual mesh orthogonality and eliminates problematic T-junction configurations. We show how such operators can be efficiently implemented using a pyramid of sparsely populated uniform grids, enhancing the regularity of operations and facilitating parallelization. A novel scheme is proposed for encoding the topology of the power diagram in the neighborhood of each octree cell, allowing us to locally reconstruct it on the fly via a lookup table, rather than resorting to costly explicit meshing. The pressure Poisson equation is solved via a highly efficient, matrix-free multigrid preconditioner for Conjugate Gradient, adapted to the power diagram discretization. We use another sparsely populated uniform grid for high resolution interface tracking with a narrow band level set representation. Using the recently introduced SPGrid data structure, sparse uniform grids in both the power diagram discretization and our narrow band level set can be compactly stored and efficiently updated via streaming operations. Additionally, we present enhancements to adaptive level set advection, velocity extrapolation, and the fast marching method for redistancing. Our overall framework gracefully accommodates the task of dynamically adapting the octree topology during simulation. We demonstrate end-to-end simulations of complex adaptive flows in irregularly shaped domains, with tens of millions of degrees of freedom.