bluuebunny/crossref_metadata_2025 huggingface dataset:
The vanishing cycles of curves in toric surfaces II
Authors: Crétois Rémi , Lang Lionel
Published: June 2018

We resume the study initiated in [R. Crétois and L. Lang, The vanishing cycles of curves in toric surfaces, I, preprint (2017), arXiv:1701.00608]. For a generic curve [Formula: see text] in an ample linear system [Formula: see text] on a toric surface [Formula: see text], a vanishing cycle of [Formula: see text] is an isotopy class of simple closed curve that can be contracted to a point along a degeneration of [Formula: see text] to a nodal curve in [Formula: see text]. The obstructions that prevent a simple closed curve in [Formula: see text] from being a vanishing cycle are encoded by the adjoint line bundle [Formula: see text]. In this paper, we consider the linear systems carrying the two simplest types of obstruction. Geometrically, these obstructions manifest on [Formula: see text] respectively as an hyperelliptic involution and as a spin structure. In both cases, we determine all the vanishing cycles by investigating the associated monodromy maps, whose target space is the mapping class group [Formula: see text]. We show that the image of the monodromy is the subgroup of [Formula: see text] preserving respectively the hyperelliptic involution and the spin structure. The results obtained here support Conjecture [Formula: see text] in [R. Crétois and L. Lang, The vanishing cycles of curves in toric surfaces, I, preprint (2017), arXiv:1701.00608] aiming to describe all the vanishing cycles for any pair [Formula: see text].
A new generalized version of Log-logistic distribution with applications in medical sciences and other applied fields
Authors: Para Bilal Ahmad , Jan Tariq Rashid
Published: June 2018

In this paper, we studied a two-parameter transmuted model of Log-logistic distribution (LLD) using the quadratic rank transmutation map technique studied by Shaw and Buckley1 as a new survival model in medical sciences and other applied fields. Statistical properties of Transmuted LLD (TLLD) are discussed comprehensively. Robust measures of skewness and kurtosis of the proposed model have also been discussed along with graphical overview. The estimation of the model parameters is performed by Maximum Likelihood (ML) method followed by a Monte Carlo (MC) simulation procedure to investigate the performance of the ML estimators and the asymptotic confidence intervals of the parameters. Applications of the proposed model to real-life data are also presented.
Input and Output Constraints in Iterative Learning Control Design for Robotic Manipulators
Authors: Sebastian Gijo , Tan Ying , Oetomo Denny , Mareels Iven
Published: June 2018

Motivated by the safety requirement of rehabilitation robotic systems for after stroke patients, this paper handles position or output constraints in robotic manipulators when the patients repeat the same task with the robot. In order to handle output constraints, if all state information is available, a state feedback controller can ensure that the output constraints are satisfied while iterative learning control (ILC) is used to learn the desired control input through iterations. By incorporating the feedback control using barrier Lyapunov function with feed-forward control (ILC) carefully, the convergence of the tracking error, the boundedness of the internal state, the boundedness of input signals can be guaranteed along with the satisfaction of the output constraints over iterations. The effectiveness of the proposed controller is demonstrated using simulations from the model of EMU, a rehabilitation robotic system.
Energy transfer to a harmonic chain under kinematic and force loadings: Exact and asymptotic solutions
Authors: Kuzkin V. A. , Krivtsov A. M.
Published: June 2018

We consider dynamics of a one-dimensional harmonic chain with harmonic on-site potential subjected to kinematic and force loadings. Under kinematic loading, a particle in the chain is displaced according to sinusoidal law. Under force loading, a harmonic force is applied to a particle. Dependence of the total energy supplied to the chain on loading frequency is investigated. Exact and asymptotic expressions for the energy are derived. For loading frequencies inside the spectrum, the energy grows in time. The rate of energy growth depends on the group velocity corresponding to loading frequency. For non-zero group velocities, the energy grows linearly. If the group velocity vanishes, behavior of the system under kinematic and force loadings is qualitatively different. Under kinematic loading, the energy is bounded, while under force loading it grows in time as [Formula: see text]. Similar problem is solved in continuum formulation for a longitudinally vibrating elastic rod. It is shown that at large times, expressions for energies of the rod and the chain are identical, provided that sound speed and density are chosen properly. Generalization of results for the case of an arbitrary periodic excitation is discussed.
Sensitivity Analysis of Hybrid Split-Step Fourier/Finite Difference Parabolic Equation Models
Authors: Aslan Mustafa , Smith Kevin B. , Moss Geoffrey
Published: June 2018

Traditionally, ocean acoustic propagation models assume the sea surface can be treated as an idealized pressure release boundary. For flat surfaces, this can easily be accomplished through a variety of modeling techniques. Rough surfaces, however, introduce additional complexities in numerical models which assume a pressure release condition. An alternative approach is to model the physical water/air interface in a manner analogous to the water/sediment interface of the bottom. However, the ocean surface boundary introduces a much larger interface discontinuity than the bottom interface. In this work, a previously developed hybrid split-step Fourier/finite-difference approach is implemented at the water/air interface. Results are compared with standard SSF smoothing approaches. Normal mode and finite element models are utilized to provide benchmark solutions. Tradeoffs between accuracy and stability are discussed, as well as the model’s ability to accurately compute transmission across the water/air interface.
Using Machine Learning to Support Qualitative Coding in Social Science
Authors: Chen Nan-Chen , Drouhard Margaret , Kocielnik Rafal , Suh Jina , Aragon Cecilia R.
Published: June 2018

Machine learning (ML) has become increasingly influential to human society, yet the primary advancements and applications of ML are driven by research in only a few computational disciplines. Even applications that affect or analyze human behaviors and social structures are often developed with limited input from experts outside of computational fields. Social scientists—experts trained to examine and explain the complexity of human behavior and interactions in the world—have considerable expertise to contribute to the development of ML applications for human-generated data, and their analytic practices could benefit from more human-centered ML methods. Although a few researchers have highlighted some gaps between ML and social sciences [51, 57, 70], most discussions only focus on quantitative methods. Yet many social science disciplines rely heavily on qualitative methods to distill patterns that are challenging to discover through quantitative data. One common analysis method for qualitative data is
qualitative coding
. In this article, we highlight three challenges of applying ML to qualitative coding. Additionally, we utilize our experience of designing a visual analytics tool for collaborative qualitative coding to demonstrate the potential in using ML to support qualitative coding by shifting the focus to identifying ambiguity. We illustrate dimensions of ambiguity and discuss the relationship between disagreement and ambiguity. Finally, we propose three research directions to ground ML applications for social science as part of the progression toward
human-centered
machine learning.
How Messenger RNA and Nascent Chain Sequences Regulate Translation Elongation
Authors: Choi Junhong , Grosely Rosslyn , Prabhakar Arjun , Lapointe Christopher P. , Wang Jinfan , Puglisi Joseph D.
Published: June 2018

Translation elongation is a highly coordinated, multistep, multifactor process that ensures accurate and efficient addition of amino acids to a growing nascent-peptide chain encoded in the sequence of translated messenger RNA (mRNA). Although translation elongation is heavily regulated by external factors, there is clear evidence that mRNA and nascent-peptide sequences control elongation dynamics, determining both the sequence and structure of synthesized proteins. Advances in methods have driven experiments that revealed the basic mechanisms of elongation as well as the mechanisms of regulation by mRNA and nascent-peptide sequences. In this review, we highlight how mRNA and nascent-peptide elements manipulate the translation machinery to alter the dynamics and pathway of elongation.
Transnational Governance for Mining and the Mineral Lifecycle
Authors: Auld Graeme , Betsill Michele , VanDeveer Stacy D.
Published: June 2018

This review focuses on transnational governance in the minerals and mining sector. Although several initiatives have emerged to address specific governance challenges in this sector, knowledge of these efforts is piecemeal and little is known about patterns in transnational governance development across this issue area. We address these gaps by reviewing the extant research literature and analyzing empirical examples of transnational minerals and mining governance, using the gold sector as an illustrative case. We identify the social, humanitarian, security, and environmental problems manifest along the mineral lifecycle and consider the extent to which existing transnational governance initiatives address these issues. We call for future scholarship that addresses the diversity of transnational governance practices in the minerals and mining sector and explains emergent patterns in the particular forms of governance that dominate this issue area, as well the types of problems that have (and have not) received attention.
Communication Between the Microbiota and Mammalian Immunity
Authors: Ost Kyla S. , Round June L.
Published: June 2018

Mammalian immune systems evolved within a diverse world dominated by microbes, making interactions between these two life-forms inevitable. Adaptive immunity protects against microbes through antigen-specific responses. In classical studies, these responses were investigated in the context of pathogenicity; however, we now know that they have significant effects on our resident microbes. In turn, microbes employ an arsenal of mechanisms to influence development and specificity of host immunity. Understanding these complex reactions will be necessary to develop microbiota-based strategies to prevent or treat disease. Here we review the literature detailing the cross talk between resident microbes with a focus on the specificity of host responses and the microbial molecules that influence them.
Epigenetic Variation and Regulation in Malaria Parasites
Authors: Duraisingh Manoj T. , Skillman Kristen M.
Published: June 2018

Eukaryotic pathogens must survive in different hosts, respond to changing environments, and exploit specialized niches to propagate. Plasmodium parasites cause human malaria during bloodstream infections, where they must persist long enough to be transmitted. Parasites have evolved diverse strategies of variant gene expression that control critical biological processes of blood-stage infections, including antigenic variation, erythrocyte invasion, innate immune evasion, and nutrient acquisition, as well as life-cycle transitions. Epigenetic mechanisms within the parasite are being elucidated, with discovery of epigenomic marks associated with gene silencing and activation, and the identification of epigenetic regulators and chromatin proteins that are required for the switching and maintenance of gene expression. Here, we review the key epigenetic processes that facilitate transition through the parasite life cycle and epigenetic regulatory mechanisms utilized by Plasmodium parasites to survive changing environments and consider epigenetic switching in the context of the outcome of human infections.
The extracellular loop of the auxiliary β1-subunit is involved in the regulation of BKCa channel mechanosensitivity
Authors: Xin Fang , Cheng Yuan , Ren Jie , Zhang Sitao , Liu Ping , Zhao Haiyan , Huang Haixia , Wang Wei
Published: June 2018

The large conductance Ca2+-activated potassium (BKCa) channel is activated by stretch. The stress-regulated exon (STREX) in α-subunits is known to affect the mechanosensitivity of BKCa channels. However, in human colonic smooth muscle cells (HCoSMCs), we found that the α-subunits without STREX (ZERO-BK) and β1-subunits could be detected yet the cells were mechanosensitive. Whether the β1-subunit is involved in the regulation of BKCa mechanosensitivity is unclear. In the present study, ZERO-BK and β1-subunits were individually expressed or coexpressed in HEK293 cells and cell-attached patch-clamp techniques were used to measure BKCa currents defining mechanosensitivity. Single-channel patch-clamp recordings from HEK293 cells cotransfected with ZERO-BK and β1-subunits showed stretch sensitivity, but there was no mechanosensitivity in HEK293 cells transfected only with ZERO-BK. We also showed that expression of the β1-subunit could increase mechanosensitivity of the STREX-type α-subunits (STREX-BK). To identify the domain in β1-subunits responsible for affecting stretch sensitivity, we expressed β1- LoopDel (chimeric β1-subunits without the extracellular loop) or β1- C TermDel (chimeric β1-subunits without COOH terminus) with ZERO-BK in HEK293 cells. The data showed that deletion of the extracellular loop but not the COOH terminus of β1-subunits virtually abolished the mechanosensitivity. These results suggest that the extracellular loop of the β1-subunit is involved in the regulation of BKCa channel mechanosensitivity and that role is independent of STREX.
Inflammation-associated changes in DOR expression and function in the mouse colon
Authors: DiCello Jesse J. , Saito Ayame , Rajasekhar Pradeep , Eriksson Emily M. , McQuade Rachel M. , Nowell Cameron J. , Sebastian Benjamin W. , Fichna Jakub , Veldhuis Nicholas A. , Canals Meritxell , Bunnett Nigel W. , Carbone Simona E. , Poole Daniel P.
Published: June 2018

Endogenous opioids activate opioid receptors (ORs) in the enteric nervous system to control intestinal motility and secretion. The μ-OR mediates the deleterious side effects of opioid analgesics, including constipation, respiratory depression, and addiction. Although the δ-OR (DOR) is a promising target for analgesia, the function and regulation of DOR in the colon are poorly understood. This study provides evidence that endogenous opioids activate DOR in myenteric neurons that may regulate colonic motility. The DOR agonists DADLE, deltorphin II, and SNC80 inhibited electrically evoked contractions and induced neurogenic contractions in the mouse colon. Electrical, chemical, and mechanical stimulation of the colon evoked the release of endogenous opioids, which stimulated endocytosis of DOR in the soma and proximal neurites of myenteric neurons of transgenic mice expressing DOR fused to enhanced green fluorescent protein. In contrast, DOR was not internalized in nerve fibers within the circular muscle. Administration of dextran sulfate sodium induced acute colitis, which was accompanied by DOR endocytosis and an increased density of DOR-positive nerve fibers within the circular muscle. The potency with which SNC80 inhibited neurogenic contractions was significantly enhanced in the inflamed colon. This study demonstrates that DOR-expressing neurons in the mouse colon can be activated by exogenous and endogenous opioids. Activated DOR traffics to endosomes and inhibits neurogenic motility of the colon. DOR signaling is enhanced during intestinal inflammation. This study demonstrates functional expression of DOR by myenteric neurons and supports the therapeutic targeting of DOR in the enteric nervous system.

NEW & NOTEWORTHY DOR is activated during physiologically relevant reflex stimulation. Agonist-evoked DOR endocytosis is spatially and temporally regulated. A significant proportion of DOR is internalized in myenteric neurons during inflammation. The relative proportion of all myenteric neurons that expressed DOR and the overlap with the nNOS-positive population are increased in inflammation. DOR-specific innervation of the circular muscle is increased in inflammation, and this is consistent with enhanced responsiveness to the DOR agonist SNC80.
Cholinergic activation of enteric glia is a physiological mechanism that contributes to the regulation of gastrointestinal motility
Authors: Delvalle Ninotchska M. , Fried David E. , Rivera-Lopez Gretchen , Gaudette Luke , Gulbransen Brian D.
Published: June 2018

The reflexive activities of the gastrointestinal tract are regulated, in part, by precise interactions between neurons and glia in the enteric nervous system (ENS). Intraganglionic enteric glia are a unique type of peripheral glia that surround enteric neurons and regulate neuronal function, activity, and survival. Enteric glia express numerous neurotransmitter receptors that allow them to sense neuronal activity, but it is not clear if enteric glia monitor acetylcholine (ACh), the primary excitatory neurotransmitter in the ENS. Here, we tested the hypothesis that enteric glia detect ACh and that glial activation by ACh contributes to the physiological regulation of gut functions. Our results show that myenteric enteric glia express both the M3 and M5 subtypes of muscarinic receptors (MRs) and that muscarine drives intracellular calcium (Ca2+) signaling predominantly through M3R activation. To elucidate the functional effects of activation of glial M3Rs, we used GFAP::hM3Dq mice that express a modified human M3R (hM3Dq) exclusively on glial fibrillary acidic protein (GFAP) positive glia to directly activate glial hM3Dqs using clozapine- N-oxide. Using spatiotemporal mapping analysis, we found that the activation of glial hM3Dq receptors enhances motility reflexes ex vivo. Continuous stimulation of hM3Dq receptors in vivo, drove changes in gastrointestinal motility without affecting neuronal survival in the ENS and glial muscarinic receptor activation did not alter neuron survival in vitro. Our results provide the first evidence that GFAP intraganglionic enteric glia express functional muscarinic receptors and suggest that the activation of glial muscarinic receptors contributes to the physiological regulation of functions.

NEW & NOTEWORTHY Enteric glia are emerging as novel regulators of enteric reflex circuits, but little is still known regarding the effects of specific transmitter pathways on glia and the resulting consequences on enteric reflexes. Here, we provide the first evidence that enteric glia monitor acetylcholine in the enteric nervous system and that glial activation by acetylcholine is a physiological mechanism that contributes to the functional regulation of intestinal reflexes.
Auditory modulation of spiking activity and local field potentials in area MT does not appear to underlie an audiovisual temporal illusion
Authors: Kafaligonul Hulusi , Albright Thomas D. , Stoner Gene R.
Published: June 2018

The timing of brief stationary sounds has been shown to alter the perceived speed of visual apparent motion (AM), presumably by altering the perceived timing of the individual frames of the AM stimuli and/or the duration of the interstimulus intervals (ISIs) between those frames. To investigate the neural correlates of this “temporal ventriloquism” illusion, we recorded spiking and local field potential (LFP) activity from the middle temporal area (area MT) in awake, fixating macaques. We found that the spiking activity of most MT neurons (but not the LFP) was tuned for the ISI/speed (these parameters covaried) of our AM stimuli but that auditory timing had no effect on that tuning. We next asked whether the predicted changes in perceived timing were reflected in the timing of neuronal responses to the individual frames of the AM stimuli. Although spiking dynamics were significantly, if weakly, affected by auditory timing in a minority of neurons, the timing of spike responses did not systematically mirror the predicted perception of stimuli. Conversely, the duration of LFP responses in β- and γ-frequency bands was qualitatively consistent with human perceptual reports. We discovered, however, that LFP responses to auditory stimuli presented alone were robust and that responses to audiovisual stimuli were predicted by the linear sum of responses to auditory and visual stimuli presented individually. In conclusion, we find evidence of auditory input into area MT but not of the nonlinear audiovisual interactions we had hypothesized to underlie the illusion.

NEW & NOTEWORTHY We utilized a set of audiovisual stimuli that elicit an illusion demonstrating “temporal ventriloquism” in visual motion and that have spatiotemporal intervals for which neurons within the middle temporal area are selective. We found evidence of auditory input into the middle temporal area but not of the nonlinear audiovisual interactions underlying this illusion. Our findings suggest that either the illusion was absent in our nonhuman primate subjects or the neuronal correlates of this illusion lie within other areas.
Winternitz Signature Scheme Using Nonadjacent Forms
Authors: Roh Dongyoung , Jung Sangim , Kwon Daesung
Published: June 2018

Hash-based signatures are gaining attention as one of the alternatives that can replace current digital signatures that are not secure against an attack by quantum computers along with lattice-based signatures, multivariate signatures, and code-based signatures. Up to now, all hash-based signatures have used binary representations to generate signatures. In this paper, we propose using the nonadjacent form (NAF) when generating signatures in hash-based signatures. Concretely, we propose a hash-based signature scheme, WSS-N, which is obtained by applying nonadjacent forms (NAF) to the Winternitz signature scheme. We prove that WSS-N is existentially unforgeable under chosen message attacks in the standard model. And we show that WSS-N needs less hash function calls compared to the Winternitz signature scheme using the binary representation, WSS-B. For a specific parameter with a 256-bit security, we can see that WSS-N generates signatures faster than WSS-B by 8%. Finally, we implement both WSS-N and WSS-B and show that WSS-N generates signatures faster than WSS-B on a desktop computer.
Matrix Metalloproteinase-1 Gene Polymorphism Associated with Ultrasound-Assessed Carotid Thickness among Older Adults
Authors: Morais Junior Gilberto Santos , Rodrigues Nathalia Oliveira , Henriques Adriane Dallanora , Tonet-Furioso Audrey Cecília , Brito Ciro José , Gomes Lucy Oliveira , Moraes Clayton Franco , Nóbrega Otávio Toledo
Published: June 2018

Background and Aim. Due to the high incidence of vascular diseases, it is necessary to identify new circulating or structural markers for predicting risk for chronic diseases. Some studies suggest that MMP1 gene polymorphisms are associated with the enzyme expression levels in situ (e.g., in atherosclerotic plaques). Objectives. Thus, the study of this polymorphism may help understanding the pathophysiology of coronary disease. Methods. We performed cross-sectional clinical and laboratory evaluations (including measurement of intima-media thickness of carotid arteries) and genotyping of the MMP1 SNP rs495366 (A/G) in 366 elderly people. Results. No significant differences between genotypes were noted for biochemical, metabolic, inflammatory, or clinical variables except for a significant difference in intima-media thickness for the left carotid artery and a trend toward significance for the right counterpart. Conclusion. Carriers of the allele associated with lower MMP1 expression (allele A) presented greater carotid thickness. We suggest that the phenomenon can be explained by impaired remodeling of the arterial wall (poor degradation of collagen fibers in this scenario), yielding carotid wall thickening and a greater intrinsic risk for cerebrovascular events.
Journal of Food Quality Thermal Degradation of Plum Anthocyanins: Comparison of Kinetics from Simple to Natural Systems
Authors: Turturică Mihaela , Stănciuc Nicoleta , Mureșan Claudia , Râpeanu Gabriela , Croitoru Constantin
Published: June 2018

The stability of anthocyanin was assessed over a temperature range of 50–120°C in different simulated plum juices in order to compare the thermal behavior in the presence of certain compounds. The results were correlated with the antioxidant activity and intrinsic fluorescence spectra. The results suggested significant changes, especially at higher temperature; hence, increase in the fluorescence intensity and some bathochromic and hypsochromic shifts were observed. Anthocyanins in natural matrices presented the highest rate for degradation, followed by the anthocyanins in juices with sugars. Values of the activation energies were 42.40 ± 6.87 kJ/mol for the degradation in water, 40.70 ± 4.25 kJ/mol for the juices with citric acid, 23.03 ± 3.53 kJ/mol for the juices containing sugars, 35.99 ± 3.60 kJ/mol for simulated juices with mixture, and 14.19 ± 2.39 kJ/mol for natural juices. A protective effect of sugars was evidenced, whereas in natural matrices, the degradation rate constant showed lower temperature dependence.
Analysis of Nonstationary Characteristics for High‐Speed Railway Scenarios
Authors: Zhou Tao , Tao Cheng , Liu Kai
Published: June 2018

This paper presents the analysis of nonstationary characteristics for high‐speed railway (HSR) scenarios, according to passive long‐term evolution‐ (LTE‐) based channel measurements. The measurement data collected in three typical scenarios, rural, station, and suburban, are processed to obtain the channel impulse responses (CIRs). Based on the CIRs, the nonstationarity of the HSR channel is studied focusing on the stationarity interval, and a four‐state Markov chain model is generated to describe the birth‐death process of multipath components. The presented results will be useful in dynamic channel modeling for future HSR mobile communication systems.
The Prevalence and Associations of Peripheral Retinopathy: Baseline Study of Guangzhou Office Computer Workers
Authors: Zhang Ting , Zuo Yajing , Wei Yantao , Huang Wenbin , Zhou Xuezhi , Liu Rongjiao , Zhong Lili , Peng Manjuan , Zhang Shaochong
Published: June 2018

Purpose. To determine the prevalence of peripheral retinopathy and its associated risk factors among a sample of Guangzhou office computer workers. Methods. A cross-sectional study of Guangzhou Chinese computer workstations and operators in different departments and units of the Guangzhou Power Supply Bureau, China, in 2016. Peripheral retinopathy was recorded and analyzed using a scanning laser ophthalmoscope (SLO; Optos, Daytona, United Kingdom) and slit-lamp microscopy combined with a three-mirror contact lens. Results. The 1934 eyes of 967 subjects (513 females and 454 males) were included in this study. In total, 79.1% of the eyes were myopic in workers aged 20–29 years, 72.9% in workers aged 30–39 years, 62.2% in workers aged 40–49 years, and 43.4% in workers aged 50–59 years (p<0.001). Most eyes had optic nerve crescents (81.3%). Various peripheral degenerations were found: 7 eyes (0.4%) had microcystoid degeneration, 40 (2.1%) had peripheral pigmentary degeneration, 87 (4.5%) had lattice degeneration, and 4 (0.2%) had snail-track degeneration. Nineteen (1.0%) eyes had paving-stone degeneration, 11 (0.6%) eyes had a retinal hole or tear, and 16 (0.8%) eyes had chorioretinal degeneration. Multivariate regression confirmed that greater axial length (OR: 1.18 (1.03, 1.35), p=0.012) and more serious spherical equivalent (OR: 0.82 (0.77, 0.88), p<0.001) were significant risk factors for peripheral retinal changes. Conclusion. Peripheral retinal degenerative changes were found in a larger proportion of younger computer workers than older ones. Myopia is occurring in younger and younger people, accompanied by peripheral retinal degeneration.
Distributed Multirobot Exploration Based on Scene Partitioning and Frontier Selection
Authors: Lopez-Perez Jose J. , Hernandez-Belmonte Uriel H. , Ramirez-Paredes Juan-Pablo , Contreras-Cruz Marco A. , Ayala-Ramirez Victor
Published: June 2018

In mobile robotics, the exploration task consists of navigating through an unknown environment and building a representation of it. The mobile robot community has developed many approaches to solve this problem. These methods are mainly based on two key ideas. The first one is the selection of promising regions to explore and the second is the minimization of a cost function involving the distance traveled by the robots, the time it takes for them to finish the exploration, and others. An option to solve the exploration problem is the use of multiple robots to reduce the time needed for the task and to add fault tolerance to the system. We propose a new method to explore unknown areas, by using a scene partitioning scheme and assigning weights to the frontiers between explored and unknown areas. Energy consumption is always a concern during the exploration, for this reason our method is a distributed algorithm, which helps to reduce the number of communications between robots. By using this approach, we also effectively reduce the time needed to explore unknown regions and the distance traveled by each robot. We performed comparisons of our approach with state-of-the-art methods, obtaining a visible advantage over other works.
Effect of Storage Temperatures on the Moisture Migration and Microstructure of Beef
Authors: Li Xia , Wang Hang , Mehmood Waris , Qian Shuyi , Sun Zhen , Zhang Chunhui , Blecker Christophe
Published: June 2018

The effects of freezing temperature on the microstructure and moisture migration of beef were investigated, aiming to provide the potential theoretical basis for the beef storage. Drip loss, surface hydrophobicity, and secondary structure of myofibrillar proteins, ice crystal, and micro- and ultrastructure of meat were analyzed at 4°C, −1°C, −6°C, −9°C, −12°C, and −18°C, respectively. Results indicated that the drip loss and surface hydrophobicity of samples stored at −12°C were significantly lower than that stored at 4°C and −1°C (p<0.05) and no significant difference with −18°C (p>0.05). Result from Fourier transform infrared spectroscopy suggested that protein denaturation occurred after storage. There was an increase in α-helices and decline in random coil at lower temperature (−12°C and −18°C). It was indicated that the samples stored at −12°C and −18°C could effectively restrain the denaturation of protein and maintain the stability of secondary structure. The analysis of the ice crystal and micro- and ultrastructure of the muscle indicated that the structure of samples stored at −12°C and −18°C had more integrity and was complete than that stored at 4°C and −1°C. The spaces (water “reservoir” and “channel”) where was the origination of drip were small. Furthermore, the results of low-field nuclear magnetic resonance and 1H magnetic relaxation image showed that the freezing at −12°C could inhibit the migration of immobilized water to free water.
Horizontal Bearing Test and Optimization of m Value for Precast Piles in Alluvium Stratum of the Yellow River
Authors: Lyu Xianzhou , Chen Zhen , Zhao Zenghui , Wang Weiming
Published: June 2018

For a pile foundation design, the value of proportional coefficient m to define the soil horizontal resist force is a significant parameter. However, different geological conditions and experimental environment have led to different m values. In this paper, an in situ test is firstly carried out on the horizontal bearing capacity of large-size precast square-piles. The piles deformation is then derived by using the optimization method from the measured data. Secondly a back analysis model is established to calculate the m value by using the simplex method, which reveals the evolution rule of the value of proportional coefficient m. Results show that the horizontal bearing characteristics of precast piles depend on the interaction force of piles and soils. The action mechanism of the soils around the piles is gradually developed with the increase in the concrete content. The horizontal critical load and the Eigenvalue of horizontal bearing capacity increased by 16.7% and 20%, respectively. It is also seen that the higher the content of the cement-soil around the piles and the longer the pile length, the bigger the m value obtained. The variation of the proportional coefficient m with the horizontal displacement of pile top is defined by three stages: rapid decaying stage, slow decaying stage, and balanced stage, respectively. The inverse analysis method on the proposed m value can accurately reflect the actual working state of piles and soils. In the depth of 3~18m in the west of Ji'nan, the range of m value is recommended as 4~6.58 MN·m-4. When Δ takes 12mm, the values of m are consistent with the result from the back analysis. In summary, the obtained m value can be effectively used to guide the design of enclosure structure in the super deep foundation pit in the Yellow River alluvial stratum.
Design Optimization of the Centrifugal Pumps via Low Fidelity Models
Authors: Siddique M. Hamid , Afzal Arshad , Samad Abdus
Published: June 2018

Low fidelity model assisted design optimization of turbomachines has reduced the total computational and experimental costs. These models are called surrogate models which mimic the actual experiments or simulations. The surrogate models can generate thousands of approximate results from a few samples, making it easy to locate the optimal solution. Ample articles reported surrogate assisted design optimization of centrifugal pumps. In this article, the authors try to give a brief overview of the surrogate based optimization technique along with its historical applications and trend of the recent use. The various key design parameters which affect the performance of the centrifugal pump have also been discussed. The effectiveness of the surrogate based optimization technique and corresponding performance metrics have been discussed.
Apis mellifera adansonii Is the Most Defensive Honeybee in Uganda
Authors: Kasangaki Patrice , Nyamasyo Gideon N. , Ndegwa Paul N. , Angiro Christopher , Kajobe Robert
Published: June 2018

Honeybee defensive behaviour is an important trait for selection of honeybees for breeding programs. We evaluated the variation in honeybee defensive behaviour with environmental factors and hive conditions. Factors such as the difference in the agro-ecological zones, colony strength, mean elevation, type of bee hive used, and the vegetation cover were considered. The number of honeybees attacking the researchers’ protective gear within one minute of disturbance was recorded per colony and analyzed. Apis m. adansonii was found to be the most defensive. Variations in the agro-ecological zones, colony strength, and mean elevation were found to significantly influence the defensive behaviour of the honeybees. Honeybee colonies in the Mid North AEZ were the most defensive. The type of bee hive and vegetation cover did not have any influence on the defensive behaviour. From this study, we suggest that selection of honeybees that are less defensive for breeding programs should consider A. m. scutellata and honeybee colonies from West Nile and Southern Highland AEZs at higher elevations.
Feedforward Feedback Pitch Control for Wind Turbine Based on Feedback Linearization with Sliding Mode and Fuzzy PID Algorithm
Authors: Ren Haijun , Zhang Hao , Deng Guang , Hou Bin
Published: June 2018

After exceeding rated power, variable speed variable pitch wind turbines need to keep output powers at rated value by adopting pitch angles. With the typical nonlinear characteristics of the wind turbines, it is difficult to control accurately by conventional linear controller. Though feedback control can realize the stability of the system, it is effective only when deviations are produced. As such, feedforward control can be applied to compensate the time-delay produced by feedback control. Accordingly, we propose a compound control strategy that combines feedback controller with feedforward controller in this paper. In feedback loop, we adopt fuzzy algorithm to adjust the parameters of PID controller. Furthermore, to overcome large variation of input wind speed, variable universe theory is proposed to optimize fuzzy algorithm. In feedforward loop, we propose feedback linearization to address nonlinear problem. Furthermore, sliding mode algorithm is supplied to improve the robustness of feedback linearization. Therefore, feedforward loop can efficiently compensate time-delay deficiency of wind turbine systems. Simulation results show that the proposed controller can enhance the control accuracy and robustness of the system.
Effects of Cr Content on Microstructure and Mechanical Properties of AlCoCrxFeNi High‐Entropy Alloy
Authors: Shun Tao-Tsung , Hung Wei-Jhe
Published: June 2018

In this study, we investigated the effects of Cr content on the crystal structure, microstructure, and mechanical properties of four AlCoCrxFeNi (x = 0.3, 0.5, 0.7, and 1.0, in molar ratio) high‐entropy alloys. AlCoCr0.3FeNi alloy contains duplex phases, which are ordered BCC phase and FCC phase. As the Cr content increases to x = 1.0, the FCC phase disappears and the microstructure exhibits a spinodal structure formed by a BCC phase and an ordered BCC phase. This result indicates that Cr is a BCC former in AlCoCrxFeNi alloys. With increasing Cr content, the alloy hardness increases from HV415 to HV498. AlCoCr0.3FeNi, AlCoCr0.5FeNi, and AlCoCr0.7FeNi exhibit a high compressive fracture strain of about 0.24 because of the formation of the FCC phase in the BCC matrix. Moreover, the highest yield stress of 1394 MPa and compressive strength of 1841 MPa presented by AlCoCrFeNi alloy are due to the existence of a nano‐net‐like spinodal structure.
Mapping of Deep Tectonic Structures of Central and Southern Cameroon by an Interpretation of Surface and Satellite Magnetic Data
Authors: Som Mbang Constantin Mathieu , Basseka Charles Antoine , Kamguia Joseph , Etamè Jacques , Njiteu Tchoukeu Cyrille Donald , Pemi Mouzong Marcelin
Published: June 2018

The aim of this study is to determine the depth of deep tectonic structures observed in the Adamawa-Yadé zone (central part of Cameroon) and propose a new structural map of this area. The horizontal gradient associated with upward continuation and the 3D Euler deconvolution methods have been applied to the Earth Magnetic Anomaly Grid 2 (EMAG2) data from the study area. The determination of the maximum magnitude of the horizontal gradient of the total magnetic intensity field reduced to the equator, in addition to the main contacts deducted by Euler solution, allowed the production of a structural map to show the fault systems for the survey area. This result reveals the existence of two structural domains which is thus confirmed by the contrast of magnetic susceptibility in the Central Cameroon Zone. The suggested depths are in the range of 3.34 km to 4.63 km. The structural map shows two types of faults (minors and majors) with W-E, N-S, NW-SE, NE-SW, ENE-WSW, WNW-ESE, NNE-SSW, and NNW-SSE trending. The major faults which are deepest (3.81 km to 4.63 km) with NE-SW, W-E, and N-S direction are very represented in the second domain which includes the Pangar-Djerem zone. This domain which recovers many localities (Ngaoundéré, Tibati, Ngaoundal, Yoko Bétaré-Oya, and Yaoundé) is associated with the Pan-African orogeny and the Cameroon Volcanic Line.
On the Effect of Control-Point Spacing on the Multisolution Phenomenon in the P3P Problem
Authors: Vynnycky M. , Reddy G. M. M.
Published: June 2018

The perspective 3-point (P3P) problem, also known as pose estimation, has its origins in camera calibration and is of importance in many fields: for example, computer animation, automation, image analysis, and robotics. One possibility is to formulate it mathematically in terms of finding the solution to a quartic equation. However, there is yet no quantitative knowledge as to how control-point spacing affects the solution structure—in particular, the multisolution phenomenon. Here, we consider this problem through an algebraic analysis of the quartic’s coefficients and its discriminant and find that there are significant variations in the likelihood of two or four solutions, depending on how the spacing is chosen. The analysis indicates that although it is never possible to remove the occurrence of the four-solution case completely, it could be possible to choose spacings that would maximize the occurrence of two real solutions. Moreover, control-point spacing is found to impact significantly on the reality conditions for the solution of the quartic equation.
Biologically Visual Perceptual Model and Discriminative Model for Road Markings Detection and Recognition
Authors: Jia Huiqun , Wei Zhonghui , He Xin , Lv You , He Dinglong , Li Muyu
Published: June 2018

The detection and recognition of arrow markings is a basic task of autonomous driving. To achieve all-day detection and recognition of arrow markings in complex environment, we propose a hybrid model by exploiting the advantages of biologically visual perceptual model and discriminative model. Firstly, the arrow markings are extracted from the complex background in the region of interest (ROI) by the biologically visual perceptual model using the frequency-tuned (FT) algorithm. Then candidates for road markings are detected as maximally stable extremal regions (MSER). In recognition stage, biologically visual perceptual model calculates the sparse solution of arrow markings using sparse learning theory. Finally, discriminative model uses the Adaptive Boosting (AdaBoost) classifier trained by sparse solution to classify arrow markings. Experimental results show that the hybrid model achieves detection and recognition of arrow markings in complex road conditions with the precision, recall, and F-measure being 0.966, 0.88, and 0.92, respectively. The hybrid model is robust and has some advantages compared with other state-of-the-art methods. The hybrid model proposed in this paper has important theoretical significance and practical value for all-day detection and recognition in complex environment.
Development of Novel Photosensitizer Using the Buddleja officinalis Extract for Head and Neck Cancer
Authors: Cho Hyejoung , Zheng Hui , Sun Qiaochu , Shi Shuhan , He YuZhu , Ahn Kyuhyeon , Kim Byunggook , Kim Hye-Eun , Kim Okjoon
Published: June 2018

Photodynamic therapy (PDT) is generally safer and less invasive than conventional strategies for head and neck cancer treatment. However, currently available photosensitizers have low selectivity for tumor cells, and the burden and side effects are so great that research is needed to develop safe photosensitizers. In this study, it was confirmed that the Buddleja officinalis (BO) extract, used in the treatment of inflammation and vascular diseases, shows fluorescence when activated by LED light, and, based on this, we aimed to develop a new photosensitive agent suitable for PDT. MTT, Diff‐Quick® staining, and DCF‐DA were performed to measure the effects of treating head and neck cancer cells with BO extract and 625 nm LED light (BO‐PDT). Cell cycle, TUNEL, and western blot assays, as well as acridine orange staining, were performed to explore the mechanism of BO‐PDT‐induced cell death. We found that when the BO extract was irradiated with 625 nm LED light, it showed sufficient fluorescence and stronger intracellular toxicity and ROS effect than the currently commercially available hematoporphyrin. BO‐PDT resulted in a decrease of mTOR activity that was correlated with an increase in the levels of ATG5, beclin‐1, and LC3‐II, which interfere with the formation of autophagosomes. In addition, BO‐PDT induced the activation of PARP and led to an increase in the expression of proapoptotic protein Bax and a decrease in the expression of the antiapoptotic protein Bcl‐2. Moreover, BO‐PDT has been shown to induce the autophagy pathway 4 h after treatment, while apoptosis was induced 16 h after treatment. Finally, we confirmed that BO‐PDT caused cell death of head and neck cancer cells via the intrinsic pathway. Therefore, we suggest that BO extract can be used as a new photosensitizer in PDT of head and neck cancer.
Oncocytoma of the Parotid Gland with Facial Nerve Paralysis
Authors: Hamada Seijiro , Fujiwara Keishi , Hatakeyama Hiromitsu , Homma Akihiro
Published: June 2018

Parotid gland tumor with facial nerve paralysis is strongly suggestive of a malignant tumor. However, several case reports have documented benign tumors of the parotid gland with facial nerve paralysis. Here, we report a case of oncocytoma of the parotid gland with facial nerve paralysis. A 61-year-old male presented with pain in his right parotid gland. Physical examination demonstrated the presence of a right parotid gland tumor and ipsilateral facial nerve paralysis of House–Brackmann (HB) grade III. Due to the facial nerve paralysis, a malignant tumor of the parotid gland was suspected and right parotidectomy was performed. Oncocytoma was confirmed histopathologically. The facial nerve paralysis was resolved 2 months after surgery. During the follow-up period (one and a half years), no recurrence was observed. As the tumor showed a distinctive dumbbell shape and increased somewhat due to inflammation (i.e., infection), the facial nerve was pinched by the enlarged tumor. Ischemia and strangulation of the nerve were considered to be the cause of the facial nerve paralysis associated with the benign tumor in this case.
Ahmed Glaucoma Valves versus EX-PRESS Devices in Glaucoma Secondary to Silicone Oil Emulsification
Authors: Qian Zhuyun , Xu Kai , Kong Xiangmei , Xu Huan
Published: June 2018

Objective. To evaluate and compare the clinical effects of Ahmed glaucoma valves (AGVs) and EX-PRESS implants on glaucoma secondary to silicone oil (SO) emulsification. Methods. A retrospective case-series study was designed. A total of 23 eyes with late intraocular pressure (IOP) elevation secondary to SO emulsification were included in the study. Antiglaucoma surgery with implantation of AGVs or EX-PRESS devices was performed. Pre- and postoperative ocular parameters were recorded at each visit during a 1-year follow-up period. The rates of complete success (IOP < 21 mmHg without medication) and qualified success (IOP < 21 mmHg with ≤3 glaucoma medications) were analyzed. Results. A total of 14 eyes underwent AGV implantation, and 9 underwent EX-PRESS implantation. The mean IOP and number of medications used at the last follow-up decreased significantly compared with that before surgery (P<0.001). The total success rate for all eyes including complete success (7/23) and qualified success (7/23) was 60.9% (14/23) at 1 year. The total success rate in the AGV group was 78.6% (11/14), whereas it was 33.3% (3/9) in the EX-PRESS group; the difference between the 2 groups was significant (P<0.05). Conclusion. For glaucoma secondary to SO emulsification, glaucoma implants could be effective at lowering IOP, and AGVs might produce better outcomes than EX-PRESS devices.