bluuebunny/crossref_metadata_2025 huggingface dataset:
Fuzzy‐based cluster head selection and cluster formation in wireless sensor networks
Authors: Shivappa Nagesha , Manvi Sunilkumar S.
Published: August 2019

Clustering is one of the mechanisms for routing in wireless sensor networks which reduces the energy and bandwidth requirements to improve network lifetime. A centralised cluster head selection and distributed cluster formation scheme by using fuzzy techniques is proposed in this study. The fuzzy c‐means is used by the sink to find cluster centres and their associated member nodes. A cluster head is selected from each cluster centre associated member nodes based on the fitness of the nodes which is computed using residual energy and distance to the cluster centre as inputs to fuzzy inference system. Nodes associate with a cluster head depending on their proximity, thereby forming clusters. Proximity will be found out by node with the assistance of signal strength parameter from cluster head which broadcast selection advertisement. This completes a round of cluster formation. At the end of each round, the nodes transmit their fitness value to their respective cluster head which in turn is forwarded to the sink. The sink selects a node with highest fitness value from each cluster centre associated members as cluster head for the next round. The scheme is compared with self‐management model and optimal clustering mechanism to demonstrate the improved performance.
DIAMOND: a distributed algorithm for vertex coloring problems and resource allocation
Authors: Miri Mohammadhasan , Mohamedpour Kamal , Darmani Yousef , Sarkar Mahasweta
Published: August 2019

The vertex colouring problem (VCP) and its generalisations have myriad applications in computer networks. To solve the VCP with colours, numerous distributed algorithms based on LOCAL model have been proposed to reduce time complexity (the number of rounds), where is the maximum vertex degree in the graph. In this paper, the authors present a distributed algorithm based on modified LOCAL model (DIAMOND) that reduces the number of rounds to one. It greedily solves the VCP with at most colours. Computational results on Geometry (GEOM) graphs show that the number of used colours to colour each instance using DIAMOND is about . DIAMOND is easily extended to solve greedily generalised VCPs in only one round. Moreover, they present two efficient resource allocation algorithms using DIAMOND. They allocate more resource to the graph compared with ‐colouring and even to ‐colouring algorithms, where is the average vertex degree of the graph. They run in two and rounds.
Ramp events forecasting based on long‐term wind power prediction and correction
Authors: Ouyang Tinghui , Huang Heming , He Yusen
Published: August 2019

To mitigate the threat to power system caused by ramp events – large wind power fluctuation, this study proposes an advanced ramp prediction approach based on event detection framework. This approach contains two successive stages of work, including wind power forecasting and ramp detection. Considering high‐performance ramp prediction requires long‐term and accurate wind power prediction results; this study also proposes a hybrid prediction model at the first stage. By using wind power curve to reflect the physic mechanism of wind power generation, data from numerical weather prediction system could be used to realise long‐term trend prediction. Then, a multivariate model is built with a data‐mining algorithm to correct system errors of the primary prediction, which is addressed to improve long‐term prediction performance. At the second stage, a modified swinging door algorithm is applied for ramp detection. Performance of both the proposed long‐term wind power prediction and the corresponding ramp prediction are computed and compared with conventional models on an actual wind dataset. Comprehensive results validated the feasibility and superiority of the proposed ramp prediction approach.
Design and implementation of Legendre‐based neural network controller in grid‐connected PV systems
Authors: Arora Ankita , Singh Alka
Published: August 2019

This study presents the development of Legendre‐based functional neural network algorithm for shunt compensation in photovoltaic (PV)‐based grid‐connected system. The controller is developed for improving power quality (PQ) and the compensator is controlled to work in current control mode. It injects the requisite compensating current depending on the nature of the load current. The compensator is also interfaced with PV source and the controller design incorporates its contribution too. Some of the PQ problems studied include curtailment of harmonics, providing necessary reactive power, power factor improvement and so on. Results under distorted grid, varying solar irradiation and variety of loads have been presented. The proposed algorithm is designed using non‐linear functional Legendre expansion of load current and has not been used for compensation or PQ problem alleviation till date. Both simulation and experimental results verify that the proposed algorithm performs far better than the adaptive popular backpropagation multilayer perceptron neural network, recurrent neural network and non‐adaptive conventional synchronous reference frame theory based techniques.
Modular and stackable power generators for efficient renewable power generation
Authors: Kails Kevin , Li Quan , Mueller Markus
Published: August 2019

Stackable power generators enable very compact electric machines with high power density. How to identify an effective way of stacking is necessary and requires new knowledge for future guidance. In this study, both possibilities of stacking modules concentrically and axially are explored and compared. An axial flux generator based on the existing double claw pole design is used as a case study. The claw pole generator, which is modular and stackable, significantly benefits on‐site installation due to its flexible small modules that can be easily transported. This is particularly important to the installation of offshore wind turbines. Superconducting field windings are applied instead of copper in such power generators, which greatly increases their power density. In order to further increase their power density and reduce mass, the authors improved the modularity of 5 MW generators and stacked them in both ways. Results show that the power density versus mass as well as volume can be improved through stacking the modules both concentrically and axially, while the former approach is much more effective. Stacking two modules of 5 MW concentrically results in a 12.1 MW power generator with a more compact structure and higher power density than the original 10 MW generator.
Optimal operation model of integrated energy system for industrial plants considering cascade utilisation of heat energy
Authors: Mu Chenlu , Ding Tao , Zeng Ziyu , Liu Peiyun , He Yuankang , Chen Tianen
Published: August 2019

As the energy crisis becomes more prominent, the issue of energy conservation and recycling is urgent. For large‐scale industrial plants, there are various forms of heat energy resources with different grades and energy storages. This study presents the detail modelling of all equipment in the integrated energy system to specify the physical operational constraints. Furthermore, an optimisation model is set up to minimise the total cost of an individual industrial plant, with the consideration of energy production equipment, energy conversion equipment and energy storage equipment in the plant. In particular, the relationship among the heat energy with different grades is described to characterise the cascade utilisation of the heat energy. Finally, a material processing factory with multi‐grade heat energy is simulated to verify the effectiveness of the proposed model with energy cascade utilisation.
Data‐based fused modal scintillation index for depth classification of a moving source using a single receiver
Authors: Shi Junjie , Sun Dajun , Fu Hongling , Liu Qingyu , Zhang Wensong
Published: August 2019

A data‐based discriminant based on fusing the scintillation of normal mode amplitudes is proposed for depth classification of surface/submerged moving source passively in a shallow water waveguide. The approach is based on a modified Hankel transform to estimate the modal wavenumber spectrum using the synthetic aperture created by the moving source. The modal wavenumber peaks are corresponding to the terms of modal excitation time series associated with the temporal modulation of an acoustic source's depth, which is used to build the fused modal scintillation index (FMSI). FMSI's robustness is presented through analysing its dependence on the SSP, sediment properties, frequency, the receiver depth, and the source depth fluctuation. Real data for a ship of opportunity and a controlled towed source collected in South China Sea preliminarily illustrates FMSI's potential for depth classification. The fused modal scintillation approach may provide a robust method for qualitative binary source depth classification.
Robust adaptive beamforming in impulsive noise environments
Authors: Hajiabadi Mojtaba , Radmanesh Hamid , Samkan Mahmood
Published: August 2019

Adaptive beamforming is one of the most important parts of a smart antenna. The most existing adaptive algorithms are based on the second‐order‐moment of the error signal like least‐mean‐square and recursive‐least‐square (RLS) algorithms. Although these algorithms are popular, their performances are not robust in impulsive noise environments. A linearly constrained correntropy‐based adaptive algorithm to solve the beamforming problem in impulsive noises is proposed in this study. The kernel width parameter of the proposed algorithm is considered to be time‐varying to deal with non‐stationary and impulsive environments. Simulation results illustrate that the proposed beamforming algorithm has a robust performance in impulsive noise. Moreover, the computational complexity of the authors’ algorithm is less than the recent algorithms presented in this literature.
Bilateral photoplethysmography for peripheral arterial disease screening in haemodialysis patients using astable multivibrator and machine learning classifier
Authors: Wu Jian‐Xing , Lin Chia‐Hung , Kan Chung‐Dann , Chen Wei‐Ling
Published: August 2019

Peripheral arterial disease (PAD) is highly prevalent in haemodialysis (HD) patients with type 2 diabetes. Atherosclerosis may occur in both lower and upper peripheral arteries, causing progressive dialysis access stenosis in HD patients. To assess the risk of PAD, non‐invasive bilateral photoplethysmography (PPG) can be used to obtain continuous variations in blood flow volume in in vivo examinations. The authors propose an astable multivibrator to model the peripheral circulation system and to produce PPG oscillation with time constants, duty ratio (rising time), and amplitude ratio of systolic and diastolic pressures. Then, the bilateral differences in the time constant and duty ratio are used to separate the normal condition from PAD. The machine learning decision‐making process utilises a screening method to automatically detect subjects with and without the risk of PAD. The radial‐based function is employed to parameterise the similarity and dissimilarity levels using probability values. Colour relation analysis incorporates the probability values into the perceptual colour relationships for PAD screening. The experimental results indicate that in comparison with bilateral timing parameters, degree of stenosis, and resistive index, the proposed screening method is efficient in preventing complications of PAD and is easily implemented in an embedded system.
Comparison of the PD characteristics of epoxy resin under exponential decay pulse and sinusoidal voltages
Authors: Mi Yan , Gui Lu , Deng Shengchu , Liu Lulu , Ouyang Wenmin
Published: August 2019

The saturable reactor insulation epoxy resin is subjected to exponential decay pulse voltage under normal operating conditions. It is of great importance to study the partial discharge (PD) mechanism of epoxy resin under exponential decay pulse and sinusoidal voltages for optimal insulation design. Thus, the difference in the PD behaviours under the exponential decay pulse and sinusoidal voltages is revealed in this study for the first time, and the PD characteristics of the two types of voltages are compared and analysed at 25 and 110°C. Compared to the results for sinusoidal voltage, a higher amplitude, lower repetitive PD inception voltage peak (RPDIV) and fewer PDs are obtained under an exponential decay pulse voltage. Additionally, for the same type of voltage, the RPDIV is lower, the PD magnitude is higher and the number of PDs is smaller at 110°C than those at 25°C. The experimental results can provide a new reference for the insulation redesign of a saturable reactor under an exponential decay pulse voltage.
Determination of electrical percolation threshold of carbon nanotube‐based epoxy nanocomposites and its experimental validation
Authors: Mohan Lekshmi , Kumar Polisetti Naveen , Karakkad Sunitha , Krishnan Sindhu Thiruthi
Published: August 2019

The electrical conductivity of polymer nanocomposites plays a critical role in applications like aerospace and electromagnetic shielding. Electrical conductivity and other electromagnetic parameters of carbon nanotube (CNT)‐based epoxy nanocomposites are being analysed in this work for their suitability in electromagnetic shielding. Unfilled epoxy and CNT epoxy nanocomposite samples with various filler loadings are prepared. Impedance measurements are conducted over the frequency range of 20 Hz–10 MHz. Micromechanics model is used for the theoretical estimation of electrical conductivity of CNT‐based epoxy nanocomposites. Interface thickness in the conventional model is modified to avoid the overestimation of electrical conductivity. DC conductivity of nanocomposites determined experimentally is found to obey classical law of percolation theory and percolation threshold is determined to be 0.17 wt% which agrees well with theoretical value of 0.18 wt% obtained using modified micromechanics model. AC conductivity is found to obey universal dynamic response. Dipolar polarisation mechanism is prominent in the tested frequency range whose frequency of occurrence increases with CNT content due to a greater number of interfaces formed between CNT and epoxy. CNT epoxy nanocomposites are found to have negative permeability thus acting as absorbers in electromagnetic shielding.
Performance enhancement of the machine‐fault diagnosis system using feature mapping, normalisation and decision fusion
Authors: Sreekumar K.T. , George Kuruvachan K. , Santhosh Kumar C. , Ramachandran K.I.
Published: August 2019

A unified fault modelling approach for machines with varying operating speeds is of interest in automating production facilities. Building a unified fault model is challenging due to the presence of speed‐specific attributes in the features derived. In this work, it is shown how feature selection, mapping, normalisation and fusion of heterogeneous systems can help enhance the performance of speed‐independent (SI) machine‐fault diagnosis systems. Statistical features, obtained after applying feature selection, are used as input to a support vector machine (SVM) back‐end classifier as the baseline system. Entropy‐based feature selection algorithm is proposed to improve the performance of the fault diagnosis system. Furthermore, to make the fault diagnosis system independent of speed, locality constrained linear coding (LLC), Fisher vector encoding (FVE) and mean and variance normalisation (MVN) are used. The LLC‐MVN system and FVE‐MVN system map the input features in terms of SI basis vectors to make the features robust to speed‐specific variations. Finally, the decision scores of the time‐domain LLC‐MVN‐SVM, frequency‐domain LLC‐MVN‐SVM systems and variational mode decomposition‐based FVE‐MVN‐SVM system were fused with appropriate weighting factors. The detection error trade‐off curve is also used as a performance measure for intelligent fault diagnosis systems.
Investigating effects of force and pressure centre signals on stabilogram analysis
Authors: Cetin Egehan , Bilgin Suleyman
Published: August 2019

In this study, the centre of pressure (COPx) and force change (Fx) in the anterior–posterior (AP) plane, the centre of pressure (COPy) and force change (Fy) signals in medial–lateral (ML) plane were compared. In order to make comparisons in this context, the time‐dependent norms of the COPx–COPy, and Fx–Fy signals (FB, COPB) of 163 subjects were calculated separately. Subsequently, the mean standard deviation values (FSTD, COPSTD) of these values generated by time‐based were obtained. The scatter plots in the AP plane and the ML plane are presented in different categories, which depend on the standard deviation values, young‐elderly of the measurement group, the firm‐soft of the ground and open‐close of the eyes. Finally, the separation successes of and were calculated by means of basic classification algorithms. According to the results obtained, it is observed that the force signals generally provide more successful results than COP signals. In the study, the highest accuracy was performed with force signals and the support vector machine algorithm separated the young‐aged group with an accuracy of 81.67%.
Life‐detection radar based on wideband chaotic signal
Authors: Xu Hang , Li Ying , Li Liqiang , Zhang Jianguo , Han Hong , Liu Li , Wang Bingjie
Published: August 2019

We propose a novel life‐detection radar using a wideband Boolean‐chaos signal as a probe signal. The range between the radar and the human target can be obtained by correlating the echo signal from the target with its delayed duplicate. This range is modulated periodically by human chest's displacements along the recording time axis and the modulation frequency is the same as the respiratory frequency. Therefore, the authors propose a life‐detection algorithm based on correlation method to detect the human target's respiratory frequency and range. Experimental results demonstrate that the authors’ radar can simultaneously detect the respiratory frequency and range of the human target behind a 20‐cm‐thick wall. In addition, the high range resolution and excellent anti‐jamming property of the chaotic radar have been demonstrated by their previous studies, which make it perform superbly in complex electromagnetic environments.
Diamond‐shaped metasurface low‐profile wideband antenna
Authors: Shi Chenyun , Cui Jie , Renli Zhang , Han Yubing
Published: August 2019

A low profile wideband metasurface (MTS) antenna based on periodically modulated diamond‐shaped patch is presented. The proposed antenna consists of diamond‐shaped MTS patches and a slotted antenna fed by a microstrip line, which excites both the quasi‐TM30 mode of MTS patches and a slot antenna mode to realise a wideband operation. Impedance bandwidth for −10 dB return loss achieves 49% of 5 GHz Wi‐Fi band (from 4.53 to 7.55 GHz). The proposed antenna maintains gain from 5 to 9.8 dB and its cross‐section dimension is 0.06λ 0.
Fabrication and photocatalytic properties of porous ZnO architectures
Authors: Cai Honglan , Guo Zhenliang , Qiao Qingan , Ren Shuhua , Zhu Dongdong , Yin Ping , Xue Zhongxin
Published: August 2019

In this work, a series of porous zinc oxide (ZnO) architectures were prepared by changing the concentration of trisodium citrate by using a green hydrothermal and calcination method, and the photocatalytic performance of the ZnO samples were investigated by using Rhodamine B as degradant under ultraviolet irradiation. The concentration of trisodium citrate had a great influence on the morphology, structure and optical properties of the ZnO samples, which together affected the photocatalytic activity. With the increase of trisodium citrate concentration, the morphology of as‐prepared hexagonal wurtzite ZnO changed from flower‐like to porous microsphere, and then formed bigger spheres which were more tightly assembled by nanosheets. The higher photocatalytic performance of ZnO microsphere prepared from 1 × 10−3 mol·l−1 trisodium citrate solution was due to the hierarchical pore structure, its better ultraviolet light absorption and higher charge separation. Moreover, the mechanism of the dye photodegradation reaction was discussed.
MicroRNAs as Regulators and Biomarkers of Platelet Function and Activity in Coronary Artery Disease
Authors: Stojkovic Stefan , Nossent Anne Yaël , Haller Paul , Jäger Bernhard , Vargas Kris G. , Wojta Johann , Huber Kurt
Published: August 2019

Microribonucleic acids (miRs) are small, noncoding ribonucleic acids (RNAs), which play an important role in the regulation of platelet function and activity. Several studies proposed a mechanistic role of platelet-related miRs in the pathophysiology of coronary artery disease (CAD) and atherothrombosis. Circulating, platelet-related miRs have been proposed as diagnostic, prognostic, as well as treatment response biomarkers in CAD and acute coronary syndrome (ACS). In this review, we summarize recent studies on the role of platelet-related miRs in the regulation of platelet function and activity. Furthermore, we review the studies investigating the role of platelet-related miRs as biomarkers in patients with CAD and ACS.
Opioid Use Disorder during Antepartum and Postpartum Hospitalizations
Authors: Kern-Goldberger Adina R. , Huang Yongmei , Polin Melanie , Siddiq Zainab , Wright Jason D. , D'Alton Mary E. , Friedman Alexander M.
Published: August 2019

Objective This study aimed to evaluate temporal trends in opioid use disorder (OUD) during antepartum and postpartum hospitalizations.

Study Design This repeated cross-sectional analysis analyzed data from the National (Nationwide) Inpatient Sample. Women aged 15 to 54 years admitted antepartum or postpartum were identified. The presence of OUD was determined based on a diagnosis of opioid abuse, opioid dependence, or opioid overdose. Temporal trends in OUD were evaluated using the Rao–Scott chi-square test. Temporal trends in opioid overdose were additionally evaluated.

Results An estimated 7,336,562 antepartum hospitalizations and 1,063,845 postpartum readmissions were included in this analysis. The presence of an OUD diagnosis during antepartum hospitalizations increased from 0.7% of patients in 1998 to 1999 to 2.9% in 2014 (p < 0.01) and during postpartum hospitalizations increased from 0.8% of patients in 1998 to 1999 to 2.1% of patients in 2014 (p < 0.01). Risk of overdose diagnoses increased significantly for both antepartum hospitalizations, from 22.7 per 100,000 hospitalizations in 1998 to 2000 to 70.3 per 100,000 hospitalizations in 2013 to 2014 (p < 0.001), and postpartum hospitalizations, from 18.8 per 100,000 hospitalizations in 1998 to 2000 to 65.2 per 100,000 hospitalizations in 2013 to 2014 (p = 0.02).

Discussion Risk of OUD diagnoses and overdoses increased over the study period for both antepartum and postpartum hospitalizations.
Association of Maternal Buprenorphine or Methadone Dose with Fetal Growth Indices and Neonatal Abstinence Syndrome
Authors: Coulson Carol C. , Lorencz Erin , Rittenhouse Katelyn , Ramage Melinda , Lorenz Kathleen , Galvin Shelley L.
Published: August 2019

Objective Our objective was to compare fetal growth and incidence of neonatal abstinence syndrome requiring treatment across pregnant women with opioid use disorders on two types and two dose categories of medication-assisted treatment.

Study Design A retrospective cohort study was conducted in a comprehensive, perinatal program in western North Carolina comparing growth percentiles on third-trimester ultrasound and at birth, and diagnosis of neonatal abstinence syndrome requiring treatment. Singletons were exposed in utero to low- to moderate-dose buprenorphine (≤16 mg/day; n = 70), high-dose buprenorphine (≥17 mg/day; n = 36), low- to moderate-dose methadone (≤89 mg/day; n = 41), or high-dose methadone (≥90 mg/day; n = 74). Multivariate analysis of variance with posthoc Bonferroni comparisons (p ≤ 0.01) and multinomial logistic regressions (adjusted odds ratio, 99% confidence interval) were conducted.

Results Differences in neonatal outcomes reached statistical significance for larger head circumference for buprenorphine doses (p = 0.01) and for longer length (p < 0.01) and lower odds of neonatal abstinence syndrome requiring treatment (p < 0.01) with low- to moderate-dose buprenorphine versus high-dose methadone.

Conclusion Among pregnant women using medication-assisted treatment for opioid use disorders, low- to moderate-dose buprenorphine (≤16 mg/day) was associated with the most favorable neonatal outcomes. However, more rigorous control of confounders with a larger sample is necessary to determine if low- to moderate-dose buprenorphine is the better treatment choice.
Impaired Arterial Elastic Properties and Endothelial Glycocalyx in Patients with Embolic Stroke of Undetermined Source
Authors: Ikonomidis Ignatios , Frogoudaki Alexandra , Vrettou Agathi-Rosa , Andreou Ioannis , Palaiodimou Lina , Katogiannis Konstantinos , Liantinioti Chryssa , Vlastos Dimitrios , Zervas Paschalis , Varoudi Maria , Lambadiari Vaia , Triantafyllidi Helen , Pavlidis George , Efentakis Panagiotis , Tsoumani Maria , Tsantes Argirios E. , Parissis John , Revela Ioanna , Andreadou Ioanna , Tsivgoulis Georgios
Published: August 2019

Background and Purpose Cardioembolism is a postulated mechanism of embolic stroke of undetermined source (ESUS). We investigated endothelial glycocalyx, aortic elastic properties, oxidative stress, and their association with left atrial (LA) function in ESUS and healthy individuals.

Methods In 90 ESUS patients (age 50.4 ± 13.2) and 90 controls with similar risk factors, we measured: (1) perfused boundary region (PBR) of the sublingual arterial microvessels (range 5–25 µm), a marker inversely related with glycocalyx thickness, (2) pulse wave velocity (PWV), central systolic blood pressure (cSBP), and augmentation index (AIx), (3) LA volume and strain using speckle-tracking imaging, and (4) malondialdehyde (MDA) and protein carbonyls (PCs), as oxidative stress markers.

Results Compared with controls, ESUS had higher PWV, PBR, MDA, and PC levels as well as higher LA volume and reduced reservoir LA strain (p < 0.05). PBR > 1.2 μm of microvessel ranging from 5 to 9 μm and PWV > 10.2 m/s were associated with ESUS on multivariable analysis (odds ratio: 2.374 and 5.429, p < 0.05, respectively) and increased the c-statistic of the initial model from 0.54 to 0.71. In ESUS, glycocalyx damage (increased PBR) was related with increased PWV (p < 0.01) which was linked with LA reservoir strain after controlling for age, sex, and risk factors (p = 0.03). Increased MDA and PC were related with glycocalyx damage, increased PWV (r = 0.67 and r = 0.52), AIx, cSBP, and aortic atheroma (p < 0.01).

Conclusion Arterial function and endothelial glycocalyx are severely impaired in ESUS and are linked to LA dysfunction suggesting their contribution to ESUS pathogenesis.

Clinical Trial Registration URL-http://www.clinicaltrials.gov. Unique identifier: NCT03609437.
Variation in Toxoplasma gondii seroprevalence: effects of site, sex, species and behaviour between insular and mainland macropods
Authors: Taggart Patrick L. , Fancourt Bronwyn A. , Peacock David , Caraguel Charles G. B. , McAllister Milton M.
Published: August 2019

Context Feral cats threaten wildlife conservation through a range of direct and indirect effects. However, most studies that have evaluated the impacts of feral cats on species of conservation significance have focussed on direct impacts such as predation; few studies have considered the indirect impacts of cat-borne disease. Toxoplasma gondii, a cat-borne parasite, causes both acute and latent disease in a range of wildlife species, and macropods are particularly susceptible. Kangaroo Island is Australia’s third largest island and supports a high density of feral cats and high seroprevalence of T. gondii in multiple species, relative to the mainland. This suggests that Kangaroo Island has a high environmental contamination with the parasite and a high risk of infection for other species. Aims We aimed to describe T. gondii seroprevalence in culled and road-killed macropods, so as to assess the effects of island versus mainland location, sex, species and behaviour. Methods Macropod sera were tested for T. gondii IgG antibodies using a commercially available modified agglutination test. Key results The seroprevalence of T. gondii in culled western grey kangaroos (Macropus fuliginosus) was significantly higher on the island (20%, 11/54 positive) than on the mainland (0%, 0/61 positive). There was no difference in T. gondii seroprevalence between culled and road-killed (21%, 21/102 positive) kangaroos from the island. The seroprevalence of T. gondii was significantly higher in female (32%, 12/38 positive) than in male (13%, 8/60 positive) kangaroos, but we observed no sex effect in tammar wallabies (Macropus eugenii), and no effect of species. Conclusions The higher T. gondii seroprevalence in insular macropods supports previous reports of higher T. gondii exposure in other Kangaroo Island fauna. The lack of difference in T. gondii seroprevalence between culled and road-killed kangaroos suggests that T. gondii-positive animals are not more vulnerable to road mortality, in contrast to that suggested previously. Implications Our findings suggest greater potential adverse conservation impacts owing to toxoplasmosis on the island than on the mainland. In light of a recent study demonstrating higher cat abundance on the island than on the mainland, the higher observed T. gondii seroprevalence in insular macropods is likely to be a consequence of higher cat density.
Closed-loop cycles of experiment design, execution, and learning accelerate systems biology model development in yeast
Authors: Coutant Anthony , Roper Katherine , Trejo-Banos Daniel , Bouthinon Dominique , Carpenter Martin , Grzebyta Jacek , Santini Guillaume , Soldano Henry , Elati Mohamed , Ramon Jan , Rouveirol Celine , Soldatova Larisa N. , King Ross D.
Published: August 2019

Significance

Systems biology involves the development of large computational models of biological systems. The radical improvement of systems biology models will necessarily involve the automation of model improvement cycles. We present here a general approach to automating systems biology model improvement. Humans are eukaryotic organisms, and the yeast
Saccharomyces cerevisiae
is widely used in biology as a “model” for eukaryotic cells. The yeast diauxic shift is the most studied cellular transformation. We combined multiple software tools with integrated laboratory robotics to execute three semiautomated cycles of diauxic shift model improvement. All the experiments were formalized and communicated to a cloud laboratory automation system (Eve) for execution. The resulting improved model is relevant to understanding cancer, the immune system, and aging.
The efficiency paradox: How wasteful competitors forge thrifty ecosystems
Authors: Vermeij Geerat J.
Published: August 2019

Organic waste, an inevitable byproduct of metabolism, increases in amount as metabolic rates (per capita power) of animals and plants rise. Most of it is recycled within aerobic ecosystems, but some is lost to the system and is sequestered in the crust for millions of years. Here, I identify and resolve a previously overlooked paradox concerning the long-term loss of organic matter. In this efficiency paradox, high-powered species are inefficient in that they release copious waste, but the ecosystems they inhabit lose almost no organic matter. Systems occupied by more efficient low-powered species suffer greater losses because of less efficient recycling. Over Phanerozoic time, ecosystems have become more productive and increasingly efficient at retaining and redistributing organic matter even as opportunistic and highly competitive producers and consumers gained power and became less efficient. These patterns and trends are driven by natural selection at the level of individuals and coherent groups, which favors winners that are more powerful, active, and wasteful. The activities of these competitors collectively create conditions that are increasingly conducive to more efficient recycling and retention of organic matter in the ecosystem.
Intermembrane transport: Glycerophospholipid homeostasis of the Gram-negative cell envelope
Authors: Powers Matthew J. , Trent M. Stephen
Published: August 2019

This perspective addresses recent advances in lipid transport across the Gram-negative inner and outer membranes. While we include a summary of previously existing literature regarding this topic, we focus on the maintenance of lipid asymmetry (Mla) pathway. Discovered in 2009 by the Silhavy group [J. C. Malinverni, T. J. Silhavy,
Proc. Natl. Acad. Sci. U.S.A.
106, 8009–8014 (2009)], Mla has become increasingly appreciated for its role in bacterial cell envelope physiology. Through the work of many, we have gained an increasingly mechanistic understanding of the function of Mla via genetic, biochemical, and structural methods. Despite this, there is a degree of controversy surrounding the directionality in which Mla transports lipids. While the initial discovery and subsequent studies have posited that it mediated retrograde lipid transport (removing glycerophospholipids from the outer membrane and returning them to the inner membrane), others have asserted the opposite. This Perspective aims to lay out the evidence in an unbiased, yet critical, manner for Mla-mediated transport in addition to postulation of mechanisms for anterograde lipid transport from the inner to outer membranes.
CD8αα homodimers function as a coreceptor for KIR3DL1
Authors: Geng Jie , Raghavan Malini
Published: August 2019

Significance

Inhibitory receptors specific for major histocompatibility class I (MHC-I) molecules regulate NK cell responses. Here, we describe that cluster of differentiation 8αα (CD8αα) works as a coreceptor to enhance interaction between MHC-I and one of these receptors, KIR3DL1. We further demonstrate that inhibition of NK cell activation by MHC-I and KIR3DL1 interaction is fine-tuned by CD8αα. By testing cytokine secretion ability, we found CD8αα+NK cells are generally better educated, and thus more responsive to abnormal cells. All these results suggest that CD8αα is an important regulator of NK cell activation.
Diverse repertoire of human adipocyte subtypes develops from transcriptionally distinct mesenchymal progenitor cells
Authors: Min So Yun , Desai Anand , Yang Zinger , Sharma Agastya , DeSouza Tiffany , Genga Ryan M. J. , Kucukural Alper , Lifshitz Lawrence M. , Nielsen Søren , Scheele Camilla , Maehr René , Garber Manuel , Corvera Silvia
Published: August 2019

Single-cell sequencing technologies have revealed an unexpectedly broad repertoire of cells required to mediate complex functions in multicellular organisms. Despite the multiple roles of adipose tissue in maintaining systemic metabolic homeostasis, adipocytes are thought to be largely homogenous with only 2 major subtypes recognized in humans so far. Here we report the existence and characteristics of 4 distinct human adipocyte subtypes, and of their respective mesenchymal progenitors. The phenotypes of these distinct adipocyte subtypes are differentially associated with key adipose tissue functions, including thermogenesis, lipid storage, and adipokine secretion. The transcriptomic signature of “brite/beige” thermogenic adipocytes reveals mechanisms for iron accumulation and protection from oxidative stress, necessary for mitochondrial biogenesis and respiration upon activation. Importantly, this signature is enriched in human supraclavicular adipose tissue, confirming that these cells comprise thermogenic depots in vivo, and explain previous findings of a rate-limiting role of iron in adipose tissue browning. The mesenchymal progenitors that give rise to beige/brite adipocytes express a unique set of cytokines and transcriptional regulators involved in immune cell modulation of adipose tissue browning. Unexpectedly, we also find adipocyte subtypes specialized for high-level expression of the adipokines adiponectin or leptin, associated with distinct transcription factors previously implicated in adipocyte differentiation. The finding of a broad adipocyte repertoire derived from a distinct set of mesenchymal progenitors, and of the transcriptional regulators that can control their development, provides a framework for understanding human adipose tissue function and role in metabolic disease.
Pressure-induced phase transitions and superconductivity in a quasi–1-dimensional topological crystalline insulator α-Bi
4
Br
4
Authors: Li Xiang , Chen Dongyun , Jin Meiling , Ma Dashuai , Ge Yanfeng , Sun Jianping , Guo Wenhan , Sun Hao , Han Junfeng , Xiao Wende , Duan Junxi , Wang Qinsheng , Liu Cheng-Cheng , Zou Ruqiang , Cheng Jinguang , Jin Changqing , Zhou Jianshi , Goodenough John B. , Zhu Jinlong , Yao Yugui
Published: August 2019

Significance

The quasi–1-dimensional bismuth bromide, α-Bi
4
Br
4
, has been predicted to be a rotational symmetry-protected topological crystalline insulator. The structural study under high pressure indicates that the α-Bi
4
Br
4
phase is stable up to 4.3 GPa. There is a rich phase diagram of physical properties under high pressure in the α-Bi
4
Br
4
phase (i.e., a pressure-induced insulator–metal transition and, most importantly, a superconductive phase near the boundary of the insulator–metal transition). These findings help to answer questions, such as whether it is possible for the symmetry-protected electrons to form Cooper pairs. The α-Bi
4
Br
4
undergoes a pressure-induced structural transition above 4.3 GPa to a triclinic
P-
1 phase, which is another superconductive phase.
Sleight is right: Cyber control as a new battleground for African elections
Authors: Amoah Michael
Published: August 2019

Sleight of hand in manipulating the computation of results has become the new might for deciding who wins presidential elections. It appears that whoever controls the computation exercises a right to take advantage and win, and whoever loses or relinquishes control of the computation loses the election. As incumbents do not want to be identified with direct interference or rigging, hacking has become an alternative means. This raises a serious challenge for election management bodies (EMBs) and a new frontier for international observation. As electronic data management has become a key battleground, international observers cannot restrict their monitoring to the manual process alone. However, individual states may have data sensitivity concerns about granting electronic monitoring access to partisan international observers. Institutionalizing internationally agreed protocols that would allow real-time monitoring of EMBs’ computer systems by international observers or forensic audits of any stage of the electoral process to investigate interference, manipulation, hacking, and counter claims, is now a necessity. At the same time, the extent to which international monitors can be trusted to be non-partisan is of equal importance and could reduce forum shopping over time.
Investigation of the Obesity Paradox in Chronic Obstructive Pulmonary Disease, According to Smoking Status, in the United States
Authors: Wu Tianshi David , Ejike Chinedu O , Wise Robert A , McCormack Meredith C , Brigham Emily P
Published: August 2019

An obesity paradox in chronic obstructive pulmonary disease (COPD), whereby overweight/obese individuals have improved survival, has been well-described. These studies have generally included smokers. It is unknown whether the paradox exists in individuals with COPD arising from factors other than smoking. Nonsmoking COPD is understudied yet represents some 25%–45% of the disease worldwide. To determine whether the obesity paradox differs between ever- and never-smokers with COPD, 1,723 adult participants with this condition were examined from 2 iterations of the National Health and Nutrition Examination Survey (1988–1994, 2007–2010), with mortality outcomes followed through December 2011. Using Cox proportional hazards models, adjusted for sociodemographic factors, lung function, and survey cycle, ever/never-smoking was found to modify the association between body mass index and hazard of death. Compared with normal-weight participants, overweight/obese participants had lower hazard of death among ever-smokers (for overweight, adjusted hazard ratio (aHR) = 0.56, 95% confidence interval (CI): 0.43, 0.74; for obesity, aHR = 0.66, 95% CI: 0.48, 0.92), but never-smokers did not (overweight, aHR = 1.41, 95% CI: 0.66, 3.03; obesity, aHR = 1.29, 95% CI: 0.48, 3.48). An obesity paradox appeared to be absent among never-smokers with COPD. This, to our knowledge, novel finding might be explained by pathophysiological differences between smoking-related and nonsmoking COPD or by smoking-associated methodological biases.
Advancing an interdisciplinary framework to study seed dispersal ecology
Authors: Beckman Noelle G , Aslan Clare E , Rogers Haldre S , Kogan Oleg , Bronstein Judith L , Bullock James M , Hartig Florian , HilleRisLambers Janneke , Zhou Ying , Zurell Damaris , Brodie Jedediah F , Bruna Emilio M , Cantrell Robert Stephen , Decker Robin R , Efiom Edu , Fricke Evan C , Gurski Katherine , Hastings Alan , Johnson Jeremy S , Loiselle Bette A , Miriti Maria N , Neubert Michael G , Pejchar Liba , Poulsen John R , Pufal Gesine , Razafindratsima Onja H , Sandor Manette E , Shea Katriona , Schreiber Sebastian , Schupp Eugene W , Snell Rebecca S , Strickland Christopher , Zambrano Jenny
Published: August 2019

Although dispersal is generally viewed as a crucial determinant for the fitness of any organism, our understanding of its role in the persistence and spread of plant populations remains incomplete. Generalizing and predicting dispersal processes are challenging due to context dependence of seed dispersal, environmental heterogeneity and interdependent processes occurring over multiple spatial and temporal scales. Current population models often use simple phenomenological descriptions of dispersal processes, limiting their ability to examine the role of population persistence and spread, especially under global change. To move seed dispersal ecology forward, we need to evaluate the impact of any single seed dispersal event within the full spatial and temporal context of a plant’s life history and environmental variability that ultimately influences a population’s ability to persist and spread. In this perspective, we provide guidance on integrating empirical and theoretical approaches that account for the context dependency of seed dispersal to improve our ability to generalize and predict the consequences of dispersal, and its anthropogenic alteration, across systems. We synthesize suitable theoretical frameworks for this work and discuss concepts, approaches and available data from diverse subdisciplines to help operationalize concepts, highlight recent breakthroughs across research areas and discuss ongoing challenges and open questions. We address knowledge gaps in the movement ecology of seeds and the integration of dispersal and demography that could benefit from such a synthesis. With an interdisciplinary perspective, we will be able to better understand how global change will impact seed dispersal processes, and potential cascading effects on plant population persistence, spread and biodiversity.
tealeaves: an R package for modelling leaf temperature using energy budgets
Authors: Muir Christopher D
Published: August 2019

Plants must regulate leaf temperature to optimize photosynthesis, control water loss and prevent damage caused by overheating or freezing. Physical models of leaf energy budgets calculate the energy fluxes and leaf temperatures for a given set leaf and environmental parameters. These models can provide deep insight into the variation in leaf form and function, but there are few computational tools available to use these models. Here I introduce a new R package called tealeaves to make complex leaf energy budget models accessible to a broader array of plant scientists. This package enables novice users to start modelling leaf energy budgets quickly while allowing experts to customize their parameter settings. The code is open source, freely available and readily integrates with other R tools for scientific computing. This paper describes the current functionality of tealeaves, but new features will be added in future releases. This software tool will advance new research on leaf thermal physiology to advance our understanding of basic and applied plant science.
XI—Responsibilities and Taking on Responsibility
Authors: Calhoun Cheshire
Published: August 2019

There is a familiar, everyday notion of a responsibility. Much of daily life on and off the job is consumed by taking care of responsibilities in this sense. But what is a responsibility, and how are responsibilities related to obligations? Reflection on the phenomenon of taking on responsibilities suggests that the concept of ‘a responsibility’ is distinct from that of ‘an obligation’, and that not all responsibilities are also obligations, even though many are.
Osseocartilaginous Rib Graft L-Strut for Nasal Framework Reconstruction
Authors: Ciolek Peter J , Hanick Andrea L , Roskies Michael , Fritz Michael A
Published: August 2019

Background

In the setting of major nasal framework reconstruction, it is critical to create a stable, warp-resistant L-strut to resist the contractile forces of healing to achieve a durable outcome.

Objectives

The authors sought to demonstrate the effectiveness of the osseocartilaginous rib graft for nasal framework reconstruction.

Methods

Retrospective analysis was performed of all patients who underwent osseocartilaginous rib graft for L-strut reconstruction from 2007 to 2017 at a tertiary care hospital. Only patients with severe framework-only defects (Type IV, Daniel Classification) or total/subtotal nasal defects (Type V, Daniel Classification) were included. Primary outcome measures were: (1) maintenance of projection; (2) graft warping; and (3) graft resorption.

Results

Twenty-six patients aged an average of 54.6 years underwent nasal framework reconstruction with an osseocartilaginous rib graft L-strut. Eighteen patients had framework-only deformities (Daniel Type IV) and 8 had total or subtotal nasal deformities (Daniel Type V). Twelve patients underwent reconstruction for autoimmune mediated deformity, 10 for malignancy, 3 for traumatic injury, and 1 for an iatrogenic deformity. Average follow-up was 21 months. There was no observed warping of the L-strut construct, and all but 2 patients demonstrated total maintenance of projection. Resorption of the caudal cartilage graft was identified as the etiology of partial loss of projection in 2 patients.

Conclusions

The osseocartilaginous rib graft L-strut provides a stable, warp-resistant construct for patients lacking major dorsal and caudal support, which may be applied to reconstruction of defects due to malignancy, autoimmune, traumatic, or iatrogenic etiologies.

Level of Evidence: 4