bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of Mst89B and CG31287 is Needed for Effective Sperm Storage and Egg Fertilization in Drosophila
Authors: Grewal Gurman , Patlar Bahar , Civetta Alberto
Published: February 2021

In Drosophila, male reproductive fitness can be affected by any number of processes, ranging from development of gametes, transfer to and storage of mature sperm within the female sperm storage organs, and utilization of sperm for fertilization. We have previously identified the 89B cytogenetic map position of D. melanogaster as a hub for genes that effect male paternity success when disturbed. Here, we used RNA interference to test 11 genes that are highly expressed in the testes and located within the 89B region for their role in sperm competition and male fecundity when their expression is perturbed. Testes-specific knockdown (KD) of bor and CSN5 resulted in complete sterility, whereas KD of CG31287, Manf and Mst89B, showed a breakdown in sperm competitive success when second to mate (P2 < 0.5) and reduced fecundity in single matings. The low fecundity of Manf KD is explained by a significant reduction in the amount of mature sperm produced. KD of Mst89B and CG31287 does not affect sperm production, sperm transfer into the female bursa or storage within 30 min after mating. Instead, a significant reduction of sperm in female storage is observed 24 h after mating. Egg hatchability 24 h after mating is also drastically reduced for females mated to Mst89B or CG31287 KD males, and this reduction parallels the decrease in fecundity. We show that normal germ-line expression of Mst89B and CG31287 is needed for effective sperm usage and egg fertilization.
Differences in Homomorphic Sex Chromosomes Are Associated with Population Divergence in Sex Determination in Carinascincus ocellatus (Scincidae: Lygosominae)
Authors: Hill Peta , Shams Foyez , Burridge Christopher P. , Wapstra Erik , Ezaz Tariq
Published: February 2021

Sex determination directs development as male or female in sexually reproducing organisms. Evolutionary transitions in sex determination have occurred frequently, suggesting simple mechanisms behind the transitions, yet their detail remains elusive. Here we explore the links between mechanisms of transitions in sex determination and sex chromosome evolution at both recent and deeper temporal scales (<1 Myr; ~79 Myr). We studied a rare example of a species with intraspecific variation in sex determination, Carinascincus ocellatus, and a relative, Liopholis whitii, using c-banding and mapping of repeat motifs and a custom Y chromosome probe set to identify the sex chromosomes. We identified both unique and conserved regions of the Y chromosome among C. ocellatus populations differing in sex determination. There was no evidence for homology of sex chromosomes between C. ocellatus and L. whitii, suggesting independent evolutionary origins. We discuss sex chromosome homology between members of the subfamily Lygosominae and propose links between sex chromosome evolution, sex determination transitions, and karyotype evolution.
Targeting Diet and Exercise for Neuroprotection and Neurorecovery in Glaucoma
Authors: Tribble James R. , Hui Flora , Jöe Melissa , Bell Katharina , Chrysostomou Vicki , Crowston Jonathan G. , Williams Pete A.
Published: February 2021

Glaucoma is a leading cause of blindness worldwide. In glaucoma, a progressive dysfunction and death of retinal ganglion cells occurs, eliminating transfer of visual information to the brain. Currently, the only available therapies target the lowering of intraocular pressure, but many patients continue to lose vision. Emerging pre-clinical and clinical evidence suggests that metabolic deficiencies and defects may play an important role in glaucoma pathophysiology. While pre-clinical studies in animal models have begun to mechanistically uncover these metabolic changes, some existing clinical evidence already points to potential benefits in maintaining metabolic fitness. Modifying diet and exercise can be implemented by patients as an adjunct to intraocular pressure lowering, which may be of therapeutic benefit to retinal ganglion cells in glaucoma.
Astrocytic Regulation of Neural Circuits Underlying Behaviors
Authors: Hwang Sun-Nyoung , Lee Jae Seung , Seo Kain , Lee Hyosang
Published: February 2021

Astrocytes, characterized by a satellite-like morphology, are the most abundant type of glia in the central nervous system. Their main functions have been thought to be limited to providing homeostatic support for neurons, but recent studies have revealed that astrocytes actually actively interact with local neural circuits and play a crucial role in information processing and generating physiological and behavioral responses. Here, we review the emerging roles of astrocytes in many brain regions, particularly by focusing on intracellular changes in astrocytes and their interactions with neurons at the molecular and neural circuit levels.
The Diverse Calpain Family in Trypanosomatidae: Functional Proteins Devoid of Proteolytic Activity?
Authors: Ennes-Vidal Vítor , Branquinha Marta Helena , dos Santos André Luis Souza , d’Avila-Levy Claudia Masini
Published: February 2021

Calpains are calcium-dependent cysteine peptidases that were originally described in mammals and, thereafter, their homologues were identified in almost all known living organisms. The deregulated activity of these peptidases is associated with several pathologies and, consequently, huge efforts have been made to identify selective inhibitors. Trypanosomatids, responsible for life-threatening human diseases, possess a large and diverse family of calpain sequences in their genomes. Considering that the current therapy to treat trypanosomatid diseases is limited to a handful of drugs that suffer from unacceptable toxicity, tough administration routes, like parenteral, and increasing treatment failures, a repurposed approach with calpain inhibitors could be a shortcut to successful chemotherapy. However, there is a general lack of knowledge about calpain functions in these parasites and, currently, the proteolytic activity of these proteins is still an open question. Here, we highlight the current research and perspectives on trypanosomatid calpains, overview calpain description in these organisms, and explore the potential of targeting the calpain system as a therapeutic strategy. This review gathers the current knowledge about this fascinating family of peptidases as well as insights into the puzzle: are we unable to measure calpain activity in trypanosomatids, or are the functions of these proteins devoid of proteolytic activity in these parasites?
An Integrated Approach for Failure Analysis of Natural Gas Transmission Pipeline
Authors: Ahmed Sk Kafi , Kabir Golam
Published: February 2021

The main aim of this study is to identify the most important natural gas pipeline failure causes and interrelation analysis. In this research, the rough analytic hierarchy process (Rough-AHP) is used to identify the natural gas pipeline failure causes rank order. Then a combination of rough decision-making trial and evaluation laboratory (DEMATEL) and interpretive structural modeling (ISM) method is applied to generate the level of importance. The comparison of traditional DEMATEL and Rough-DEMATEL are also performed to establish the cause-effect interrelation diagram. Finally, the Bayesian Belief Network (BBN) is combined with Rough DEMATEL and ISM to identify the interrelation analysis among the most crucial failure causes. As a result, the energy supply company and government policymaker can take necessary safety plan and improve the operation. The main outcome of this study is to improve the security management and reduce the potential failure risks.
The Influence of the Powder Characteristics on 316L Stainless Steel Coatings Sprayed by Cold Gas Spray
Authors: Vaz Rodolpho F. , Silvello Alessio , Sanchez Javier , Albaladejo Vicente , Cano Irene García
Published: February 2021

Thermally sprayed 316L stainless steel coatings are commonly used on metallic structures due to their corrosion and wear resistance when compared to carbon steel. Cold Gas Spray (CGS) is a convenient thermal spray process to deposit 316L coatings, producing thick and very dense coatings, with almost no deleterious changes on the feedstock properties to the coating condition. The powder characteristics have influence on the microstructure of the coating, such as porosity and oxide contents, which alter its corrosion and wear behavior. CGS is an efficient technique to reduce the problems associated with material melting commonly found in other conventional thermal spray methods. In this work, different 316L powders, produced by different manufacturers, were deposited by CGS, applying the same equipment and parameters, with the objective to evaluate the relation between the powders’ characteristics and coating properties. Their microstructure, adherence, hardness, as well as the performance on corrosion and wear testing were evaluated. The water atomized powders presented in general better results than gas atomized powders.
Microstructural Charactistics of Plasma Sprayed NiCrBSi Coatings and Their Wear and Corrosion Behaviors
Authors: Huang Songqiang , Zhou Jingzhong , Sun Kuoteng , Yang Hailiang , Cai Weichen , Liu Yi , Zhou Ping , Wu Shuangjie , Li Hua
Published: February 2021

Nickel-based alloys are commonly used as protective coating materials for surface protection applications owing to their superior resistance to corrosion, wear and high-temperature oxidation. It is urgent to study the fundamental mechanism between the structure and corrosion properties of the Nickel-base composite coatings. This paper, therefore, focuses on clarifying the mechanisms of the microstructure influencing the acid corrosion and mechanical characteristics of the as-sprayed NiCrBSi coating and post-heat-treated coating. The formation mechanisms of the amorphous phase of flat particles during the plasma spray process were studied by using X-ray diffraction analysis, Raman spectroscopy and confocal laser scanning microscope at first. Then the evolutionary process of the corrosion structure and phase of the coating in the accelerated corrosion experiment is directly visualized by using scanning electron microscopy and energy spectrum analysis. The mechanical properties of the amorphous NiCrBSi coatings are lastly measured by microhardness and friction wear tests. The critical phenomena and results help to elucidate the relative influence of the surface features of atmospheric plasma sprayed coatings on acid corrosion responses and wear resistance, aiming at contributing to the development of a protective technique for electrical engineering.
Impact of Music Played in an Automatic Milking System on Cows’ Milk Yield and Behavior—A Pilot Study
Authors: Lemcke Marie-Christine , Ebinghaus Asja , Knierim Ute
Published: February 2021

Practical experience suggests that music can have a positive effect on the welfare of dairy cows, which for some other animal species has been shown in earlier studies. Music could, furthermore, be a useful tool to support, for example, daily milking routines. In this pilot study we explored effects of music inside an automatic milking system (AMS) on cows’ milk yield and behavior. The experiment was conducted on a Finnish dairy farm with 56 cows in loose housing. Over two 2-day periods without and with selected music pieces played inside the AMS, data on daily milk yield (DMY), selection gate passing frequency (GP), milking frequency (MF), and milking interval (MI) were recorded. For analyses, data of 17 Holstein-Friesian cows were used. At cow level, mean values over repeated measurements without and with music were calculated, and analyzed by paired t-tests (DMY, MF) or Wilcoxon tests (MI, GP). During intervals with music versus without, cows passed the selection gate more often (15.8 versus 13.8) and had higher MF (3.0 vs. 2.8). No differences were found in MI (07:49:21 vs. 08:37:38) and DMY (36.5 vs. 37.0). The latter might be explained by a ceiling effect. Overall, the results suggest that the investigated sample of cows perceived the selected music as attractive and that playing music might be a practical tool to reduce necessary efforts of driving cows to milking.
A Crash Recovery Scheme for a Hybrid Mapping FTL in NAND Flash Storage Devices
Authors: Park Jong-Hyeok , Park Dong-Joo , Chung Tae-Sun , Lee Sang-Won
Published: February 2021

An FTL (flash translation layer), which most flash storage devices are equipped with, needs to guarantee the consistency of modified metadata from a sudden power failure. This crash recovery scheme significantly affects the writing performance of a flash storage device during its normal operation, as well as its reliability and recovery performance; therefore, it is desirable to make the crash recovery scheme efficient. Despite the practical importance of a crash recovery scheme in an FTL, few works exist that deal with the crash recovery issue in FTL in a comprehensive manner. This study proposed a novel crash recovery scheme called FastCheck for a hybrid mapping FTL called Fully Associative Sector Translation (FAST). FastCheck can efficiently secure the newly generated address-mapping information using periodic checkpoints, and at the same time, leverages the characteristics of an FAST FTL, where the log blocks in a log area are used in a round-robin way. Thus, it provides two major advantages over the existing FTL recovery schemes: one is having a low logging overhead during normal operations in the FTL and the other to have a fast recovery time in an environment where the log provisioning rate is relatively high, e.g., over 20%, and the flash memory capacity is very large, e.g., 32 GB or 64 GB.
Compact Double Notch Coplanar and Microstrip Bandstop Filters Using Metamaterial—Inspired Open Ring Resonators
Authors: Hinojosa Juan , Martínez-Viviente Félix L. , Alvarez-Melcon Alejandro
Published: February 2021

Compact double notch coplanar and microstrip bandstop filters are described. They are based on a version of the open interconnected split ring resonator (OISRR) integrated in microstrip or coplanar waveguides. The OISRR introduces an RLC resonator connected in parallel with the propagating microstrip line. Therefore, this resonator can be modeled as a shunt circuit to ground, with the R, L and C elements connected in series. The consequence for the frequency response of the device is a notch band at the resonant frequency of the RLC shunt circuit. The number of notch bands can be controlled by adding more OISRRs, since each pair of rings can be modeled as a shunt circuit and therefore introduces an additional notch band. In this paper, we demonstrate that these additional rings can be introduced in a concentric way in the same cell, so the size of the device does not increase and a compact multi-notch bandstop response is achieved, with the same number of notch bands as pairs of concentric rings, plus an additional spurious band at a higher frequency.
Comparative Study of Optimal Multivariable LQR and MPC Controllers for Unmanned Combat Air Systems in Trajectory Tracking
Authors: Ortiz Alvaro , Garcia-Nieto Sergio , Simarro Raul
Published: February 2021

Guidance, navigation, and control system design is, undoubtedly, one of the most relevant issues in any type of unmanned aerial vehicle, especially in the case of military missions. This task needs to be performed in the most efficient way possible, which involves trying to satisfy a set of requirements that are sometimes in opposition. The purpose of this article was to compare two different control strategies in conjunction with a path-planning and guidance system with the objective of completing military missions in the most satisfactory way. For this purpose, a novel dynamic trajectory-planning algorithm is employed, which can obtain an appropriate trajectory by analyzing the environment as a discrete 3D adaptive mesh and performs a softening process a posteriori. Moreover, two multivariable control techniques are proposed, i.e., the linear quadratic regulator and the model predictive control, which were designed to offer optimal responses in terms of stability and robustness.
A Polyimide-Based Flexible Monopole Antenna Fed by a Coplanar Waveguide
Authors: Cang Dingyong , Wang Zhiliang , Qu Huiwen
Published: February 2021

A 2.4 GHz flexible monopole antenna fed by a coplanar waveguide (CPW) was presented on polyimide (PI) as the dielectric substrate, which was fabricated by in situ self-metallization. The technology does not depend on expensive equipment or complex experimental environments, including hydrolysis, ion exchange, and reduction reaction. The measurement results show that the resonance frequency of the proposed antenna is 2.28 GHz, the bandwidth is 2.06–2.74 GHz, and the relative bandwidth is 28.33% under the flat state. The bending and folding test was also carried out. Whether it was flat, bent, or folded, the measured results met the requirements of the antenna. A fatigue test was carried out to illustrate that the prepared film has high mechanical flexibility, which expands the application field of antenna.
A Low-Cost and Efficient Microstrip-Fed Air-Substrate-Integrated Waveguide Slot Array
Authors: Li Linfeng , Yan Jie-Bang
Published: February 2021

A microstrip-fed air-substrate-integrated waveguide (ASIW) slot array with high efficiency and low cost is presented. The design cuts out the substrate material within SIW, replaces the vias with metallic sidewalls, and uses a simple microstrip line-waveguide transition to feed the slot array. Radiating slots are cut on a 5-mil brass-plate, which covers the top of the substrate cutout to resemble a hollow waveguide structure. This implementation provides a simple and efficient antenna array solution for millimeter-wave (mm-wave) applications. Meanwhile, the fabrication is compatible with the standard printed circuit board (PCB) manufacturing process. To demonstrate the concept, a 4-element ASIW slot array working at the n257 band for 5G communications was designed using low-cost Rogers 4350B and FR4 substrate materials. Our simulation result shows 18% more efficiency than a conventional SIW slot array using the same substrate. The fabricated prototype shows |S11| < −15 dB over 27–29 GHz and a peak realized gain of 10.1 dBi at 28.6 GHz. The design procedure, prototyping process, and design analysis are discussed in the paper.
Image Distortion and Rectification Calibration Algorithms and Validation Technique for a Stereo Camera
Authors: Kim Jonguk , Bae Hyansu , Lee Suk Gyu
Published: February 2021

This paper focuses on the calibration problem using stereo camera images. Currently, advanced vehicle systems such as smart cars and mobile robots require accurate and reliable vision in order to detect obstacles and special marks around. Such modern vehicles can be equipped with sensors and cameras together or separately. In this study, we propose new methodologies of stereo camera calibration based on the correction of distortion and image rectification. Once the calibration is complete, the validation of the corrections is presented followed by an evaluation of the calibration process. Usually, the validation section is not jointly considered with the calibration in other studies. However, the mass production of cameras widely uses the validation techniques in calibrations owned by manufacturing businesses. Here, we aim to present a single process for the calibration and validation of stereo cameras. The experiment results showed the disparity maps in comparison with another study and proved that the proposed calibration methods can be efficient.
A Study on Re-Engagement and Stabilization Time on Take-Over Transition in a Highly Automated Driving System
Authors: Kim Hyunsuk , Kim Woojin , Kim Jungsook , Lee Seung-Jun , Yoon Daesub , Jo Junghee
Published: February 2021

In the case of level 3 automated vehicles, in order to safely and quickly transfer control authority rights to manual driving, it is necessary that a study be conducted on the characteristics of human factors affecting the transition of manual driving. In this study, we conducted three experiments to compare the characteristics of human factors that influence the driver’s quality of response when re-engaging and stabilizing manual driving. The three experiments were conducted sequentially by dividing them into a normal driving situation, an obstacle occurrence situation in front, and an obstacle and congestion on surrounding roads. We performed a statistical analysis and classification and regression tree (CART) analysis using experimental data. We found that as the number of trials increased, there was a learning effect that shortened re-engagement times and increased the proportion of drivers with good response times. We found that the stabilization time increased as the experiment progressed, as obstacles appeared in front and traffic density increased in the surrounding lanes. The results of the analysis are useful for vehicle developers designing safer human–machine interfaces and for governments developing guidelines for automated driving systems.
Study of Injection Method for Maximizing Oil-Cooling Performance of Electric Vehicle Motor with Hairpin Winding
Authors: Ha Taewook , Kim Dong Kyu
Published: February 2021

The oil injection method was studied to maximize the cooling performance of an electric vehicle motor with a hairpin winding. The cooling performance of the motor using the oil cooling method is proportional to the contact area of the oil and the coil. A numerical analysis was conducted to examine the effect of the spray nozzle type on the oil flow. The dripping nozzle forms the thickest oil film on the coil, making it the most effective for cooling of hairpin-type motors. Subsequently, an experimental study was conducted to optimize the nozzle diameter and number of nozzles. When the inlet diameter and number was 6.35 mm and 6, the oil film formation rate was 53%, yielding the most uniform oil film. Next, an experiment was performed to investigate the effects of the oil temperature and flow rate on the oil flow. The oil film formation rate was the highest (83%) when the oil temperature was 40 °C and the flow rate was 6 LPM.
Huber-Based Robust Unscented Kalman Filter Distributed Drive Electric Vehicle State Observation
Authors: Wan Wenkang , Feng Jingan , Song Bao , Li Xinxin
Published: February 2021

Accurate and real-time acquisition of vehicle state parameters is key to improving the performance of vehicle control systems. To improve the accuracy of state parameter estimation for distributed drive electric vehicles, an unscented Kalman filter (UKF) algorithm combined with the Huber method is proposed. In this paper, we introduce the nonlinear modified Dugoff tire model, build a nonlinear three-degrees-of-freedom time-varying parametric vehicle dynamics model, and extend the vehicle mass, the height of the center of gravity, and the yaw moment of inertia, which are significantly influenced by the driving state, into the vehicle state vector. The vehicle state parameter observer was designed using an unscented Kalman filter framework. The Huber cost function was introduced to correct the measured noise and state covariance in real-time to improve the robustness of the observer. The simulation verification of a double-lane change and straight-line driving conditions at constant speed was carried out using the Simulink/Carsim platform. The results show that observation using the Huber-based robust unscented Kalman filter (HRUKF) more realistically reflects the vehicle state in real-time, effectively suppresses the influence of abnormal error and noise, and obtains high observation accuracy.
Prediction Performance Analysis of Artificial Neural Network Model by Input Variable Combination for Residential Heating Loads
Authors: Lee Chanuk , Jung Dong Eun , Lee Donghoon , Kim Kee Han , Do Sung Lok
Published: February 2021

In Korea apartment buildings, most energy is consumed as heating energy. In order to reduce heating energy in apartment buildings, it is required to reduce the amount of energy used in heating systems. Energy saving in heating systems can be achieved through operation and control based on efficient operation plans. The efficient operation plan of the heating system should be based on the predicted heating load. Thus, various methods have been developed for predicting heating loads. Recently, artificial intelligence techniques (e.g., ANN: artificial neural network) have been used to predict heating loads. The process for determination of input data variables is necessary to obtain the accuracy of predicted results using an ANN model. However, there is a lack of studies to evaluate the accuracy level of the predicted results caused by the selection and combination of input variables. There is a need to evaluate the performance of an ANN model for prediction of residential heating loads. Therefore, the purpose of this study is, for a residential building, to evaluate the accuracy levels of predicted heating loads using an ANN model with various combinations of input variables. To achieve the study purpose, each case was classified according to the combination of the input variables and the prediction results were analyzed. Through this, the worst, mean, and best were selected according to the predicted performance. In addition, an actual case was selected consisting of variables that can be measured in an actual building. The derived cv(RMSE) of each case resulted in a percentage value of 38.2% for the worst, 7.3% for the mean, 3.0% for the best, and 5.4% for the actual. The largest difference between the best and worst resulted in 33.2%, and thus the precision of the predicted heating loads was highly affected by the selection and combination of the input variables used for the ANN model.
High Performance Graph Data Imputation on Multiple GPUs
Authors: Zhou Chao , Zhang Tao
Published: February 2021

In real applications, massive data with graph structures are often incomplete due to various restrictions. Therefore, graph data imputation algorithms have been widely used in the fields of social networks, sensor networks, and MRI to solve the graph data completion problem. To keep the data relevant, a data structure is represented by a graph-tensor, in which each matrix is the vertex value of a weighted graph. The convolutional imputation algorithm has been proposed to solve the low-rank graph-tensor completion problem that some data matrices are entirely unobserved. However, this data imputation algorithm has limited application scope because it is compute-intensive and low-performance on CPU. In this paper, we propose a scheme to perform the convolutional imputation algorithm with higher time performance on GPUs (Graphics Processing Units) by exploiting multi-core GPUs of CUDA architecture. We propose optimization strategies to achieve coalesced memory access for graph Fourier transform (GFT) computation and improve the utilization of GPU SM resources for singular value decomposition (SVD) computation. Furthermore, we design a scheme to extend the GPU-optimized implementation to multiple GPUs for large-scale computing. Experimental results show that the GPU implementation is both fast and accurate. On synthetic data of varying sizes, the GPU-optimized implementation running on a single Quadro RTX6000 GPU achieves up to 60.50× speedups over the GPU-baseline implementation. The multi-GPU implementation achieves up to 1.81× speedups on two GPUs versus the GPU-optimized implementation on a single GPU. On the ego-Facebook dataset, the GPU-optimized implementation achieves up to 77.88× speedups over the GPU-baseline implementation. Meanwhile, the GPU implementation and the CPU implementation achieve similar, low recovery errors.
Collaborative Filtering Based on a Variational Gaussian Mixture Model
Authors: Yang FengLei , Liu Fei , Liu ShanShan
Published: February 2021

Collaborative filtering (CF) is a widely used method in recommendation systems. Linear models are still the mainstream of collaborative filtering research methods, but non-linear probabilistic models are beyond the limit of linear model capacity. For example, variational autoencoders (VAEs) have been extensively used in CF, and have achieved excellent results. Aiming at the problem of the prior distribution for the latent codes of VAEs in traditional CF is too simple, which makes the implicit variable representations of users and items too poor. This paper proposes a variational autoencoder that uses a Gaussian mixture model for latent factors distribution for CF, GVAE-CF. On this basis, an optimization function suitable for GVAE-CF is proposed. In our experimental evaluation, we show that the recommendation performance of GVAE-CF outperforms the previously proposed VAE-based models on several popular benchmark datasets in terms of recall and normalized discounted cumulative gain (NDCG), thus proving the effectiveness of the algorithm.
Oscillatory Bifurcations in Porous Layers with Stratified Porosity, Driven by Each Coefficient of the Spectrum Equation
Authors: Rionero Salvatore
Published: February 2021

The onset of oscillatory bifurcations in a porous horizontal layer L, uniformly rotating about a vertical axis, with vertically stratified porosity, heated from below and salted from above and below, is investigated. Denoting by Pi,(i=1,2), the Prandtl numbers of the salt Si salting L from below (i=1) and above (i=2) respectively, it is shown that: (i) in L the oscillatory bifurcations can occur only if one of the structural conditions P1>1,P2<1 or P1=1,P2<1 or P1>1,P2=1 is verified; (ii) exists a bound R¯2 for the Rayleigh number R2 of S2 such that R2<R¯2 guarantees the absence of cold convection; (iii) via a new approach based on the instability power of each coefficient of the spectrum equation, criteria of existence, location and frequency of oscillatory (Hopf) bifurcations are furnished for any porosity stratification law. These criteria, as far as we know are, for the case at stake, the first criteria of Hopf bifurcations appearing in literature. We are confident that, via experimental results, will be validated.
Effect of Strain Measurement Layout on Damage Detection and Localization in a Free Falling Compliant Cylinder Impacting a Water Surface
Authors: Mercuri Alessandro , Fanelli Pierluigi , Ubertini Stefano , Falcucci Giacomo , Jannelli Elio , Biscarini Chiara
Published: February 2021

The need for effective and reliable damage detection and localization systems is growing in several engineering fields, in particular in water impact problems characterized by impulsive loading conditions, high amplitude vibrations and large local deformations. In this paper, we further develop the approach presented in previous works to detect damage of water-impacting structures. Specifically, we provide a set of experimental tests on a flexible plastic cylinder impacting the water after a 50 cm free fall. The cylindrical specimen is artificially damaged in a known position. Strain measurements are performed through a set of nine fiber Bragg gratings distributed along the circumference of a cylinder section. We show that strain sensors can be used as reference sensors, for structure displacements reconstruction, and control sensors, for damage detection purposes, and the computation of the difference between measured and expected deformation may allow damage detection. Moreover, we investigate how exchanging control and reference sensors in the same sensor arrangement affect damage detection and localization.
Application of Fractal Dimension of Terrestrial Laser Point Cloud in Classification of Independent Trees
Authors: Zhang Ju , Hu Qingwu , Wu Hongyu , Su Junying , Zhao Pengcheng
Published: February 2021

Tree precise classification and identification of forest species is a core issue of forestry resource monitoring and ecological effect assessment. In this paper, an independent tree species classification method based on fractal features of terrestrial laser point cloud is proposed. Firstly, the terrestrial laser point cloud data of an independent tree is preprocessed to obtain terrestrial point clouds of independent tree canopy. Secondly, the multi-scale box-counting dimension calculation algorithm of independent tree canopy dense terrestrial laser point cloud is proposed. Furthermore, a robust box-counting algorithm is proposed to improve the stability and accuracy of fractal dimension expression of independent tree point cloud, which implementing gross error elimination based on Random Sample Consensus. Finally, the fractal dimension of a dense terrestrial laser point cloud of independent trees is used to classify different types of independent tree species. Experiments on nine independent trees of three types show that the fractal dimension can be stabilized under large density variations, proving that the fractal features of terrestrial laser point cloud can stably express tree species characteristics, and can be used for accurate classification and recognition of forest species.
Optimal Control and Positional Controllability in a One-Sector Economy
Authors: Grigorenko Nikolai , Luk’yanova Lilia
Published: February 2021

A model of production funds acquisition, which includes two differential links of the zero order and two series-connected inertial links, is considered in a one-sector economy. Zero-order differential links correspond to the equations of the Ramsey model. These equations contain scalar bounded control, which determines the distribution of the available funds into two parts: investment and consumption. Two series-connected inertial links describe the dynamics of the changes in the volume of the actual production at the current production capacity. For the considered control system, the problem is posed to maximize the average consumption value over a given time interval. The properties of optimal control are analytically established using the Pontryagin maximum principle. The cases are highlighted when such control is a bang-bang, as well as the cases when, along with bang-bang (non-singular) portions, control can contain a singular arc. At the same time, concatenation of singular and non-singular portions is carried out using chattering. A bang-bang suboptimal control is presented, which is close to the optimal one according to the given quality criterion. A positional terminal control is proposed for the first approximation when a suboptimal control with a given deviation of the objective function from the optimal value is numerically found. The obtained results are confirmed by the corresponding numerical calculations.
EU Demand for Defense, 1990–2019: A Strategic Spatial Approach
Authors: George Justin , Sandler Todd
Published: February 2021

For 1990–2019, this study presents two-step GMM estimates of EU members’ demands for defense spending based on alternative spatial-weight matrices. In particular, EU spatial connectivity is tied to EU membership status, members’ contiguity, contiguity and power projection, inverse distance, and arms trade. At a Nash equilibrium, our EU demand equations are derived explicitly from a spatially based game-theoretical model of alliances. Myriad spatial linkages among EU members provide a robust free-riding finding, which differs from the spatial and non-spatial literature on EU defense spending. Even though the EU applies common trade policies and allows for unrestricted labor movement among members, members’ defense responses adhered to those of a defense alliance. Moreover, EU defense spending exhibits positive responses to GDP and transnational terrorist attacks, and a negative response to population. During the sample period, EU members did not view Russia as a military threat.
Occurrence of Antibiotic Resistance Genes in Hermetia illucens Larvae Fed Coffee Silverskin Enriched with Schizochytrium limacinum or Isochrysis galbana Microalgae
Authors: Milanović Vesna , Roncolini Andrea , Cardinali Federica , Garofalo Cristiana , Aquilanti Lucia , Riolo Paola , Ruschioni Sara , Corsi Lorenzo , Isidoro Nunzio , Zarantoniello Matteo , Olivotto Ike , Ceccobelli Simone , Tavoletti Stefano , Clementi Francesca , Osimani Andrea
Published: February 2021

Hermetia illucens larvae are among the most promising insects for use as food or feed ingredients due to their ability to convert organic waste into biomass with high-quality proteins. In this novel food or feed source, the absence of antibiotic-resistant bacteria and their antibiotic resistance (AR) genes, which could be horizontally transferred to animal or human pathogens through the food chain, must be guaranteed. This study was conducted to enhance the extremely scarce knowledge on the occurrence of AR genes conferring resistance to the main classes of antibiotics in a rearing chain of H. illucens larvae and how they were affected by rearing substrates based on coffee silverskin supplemented with increasing percentages of Schizochytrium limacinum or Isochrysis galbana microalgae. Overall, the PCR and nested PCR assays showed a high prevalence of tetracycline resistance genes. No significant effect of rearing substrates on the distribution of the AR genes in the H. illucens larvae was observed. In contrast, the frass samples were characterized by a significant accumulation of AR genes, and this phenomenon was particularly evident for the samples collected after rearing H. illucens larvae on substrates supplemented with high percentages (>20%) of I. galbana. The latter finding indicates potential safety concerns in reusing frass in agriculture.
Clinical Features, Inpatient Trajectories and Frailty in Older Inpatients with COVID-19: A Retrospective Observational Study
Authors: Osuafor Christopher N. , Davidson Catriona , Mackett Alistair J. , Goujon Marie , Van Der Poel Lelane , Taylor Vince , Preller Jacobus , Goudie Robert J. B. , Keevil Victoria L.
Published: February 2021

Introduction: We describe the clinical features and inpatient trajectories of older adults hospitalized with COVID-19 and explore relationships with frailty. Methods: This retrospective observational study included older adults admitted as an emergency to a University Hospital who were diagnosed with COVID-19. Patient characteristics and hospital outcomes, primarily inpatient death or death within 14 days of discharge, were described for the whole cohort and by frailty status. Associations with mortality were further evaluated using Cox Proportional Hazards Regression (Hazard Ratio (HR), 95% Confidence Interval). Results: 214 patients (94 women) were included of whom 142 (66.4%) were frail with a median Clinical Frailty Scale (CFS) score of 6. Frail compared to nonfrail patients were more likely to present with atypical symptoms including new or worsening confusion (45.1% vs. 20.8%, p < 0.001) and were more likely to die (66% vs. 16%, p = 0.001). Older age, being male, presenting with high illness acuity and high frailty were independent predictors of death and a dose–response association between frailty and mortality was observed (CFS 1–4: reference; CFS 5–6: HR 1.78, 95% CI 0.90, 3.53; CFS 7–8: HR 2.57, 95% CI 1.26, 5.24). Conclusions: Clinicians should have a low threshold for testing for COVID-19 in older and frail patients during periods of community viral transmission, and diagnosis should prompt early advanced care planning.
Heavy Load Carrying and Symptoms of Pelvic Organ Prolapse among Women in Tanzania and Nepal: An Exploratory Study
Authors: Koyuncu Aybüke , Kadota Jillian L. , Mnyippembe Agatha , Njau Prosper F. , Sijali Tula Ram , McCoy Sandra I. , Bates Michael N. , Harris-Adamson Carisa , Prata Ndola
Published: February 2021

Heavy load carrying of water, firewood, and sand/stones is a ubiquitous activity for women living in developing countries. Although the intra-abdominal pressure associated with heavy load carrying is hypothesized to increase the risk of pelvic organ prolapse (POP) among women, relevant epidemiologic data are lacking. We conducted a comparative study involving two exploratory cross-sectional studies among convenience samples of women carrying heavy loads, with different characteristics: (1) as part of their activities for daily living, in Shinyanga region, Tanzania; and (2) working as sand miners in Pokhara, Nepal. Women were categorized has having “low” or “high” load-carrying exposures based on the measured weights of the loads being carried at the time of the survey, as well as on self-reported duration and frequency of load carrying. A summary score for lower abdominal discomfort suggestive of POP was generated using questions from the Pelvic Organ Prolapse Distress Inventory (POPDI-6). Women with higher load carrying exposures had on average higher discomfort scores in both Tanzania (adjusted prevalence difference (PDa) = 3.7; 95% CI: −3.8–11.3; p = 0.33) and Nepal (PDa = 9.3; 95% CI: −4.9–23.6; p = 0.18). We identified trends suggestive of an association between increasing heavy load carrying exposures and symptoms of lower abdominal discomfort. Our findings underscore the need for larger epidemiologic studies of the potential adverse reproductive health effects of heavy load carrying activities on women in developing countries.
The Impact of SARS-CoV-2 Outbreak on the Polish Dental Community’s Standards of Care—A Six-Month Retrospective Survey-Based Study
Authors: Dalewski Bartosz , Palka Lukasz , Kiczmer Paweł , Sobolewska Ewa
Published: February 2021

Currently, SARS-CoV-2 is the primary pathogen worldwide, disrupting most of our everyday activities. The study aim was to evaluate its impact on the Polish dental community, standards of care, health, and welfare. Methods: A Google Forms survey was conducted among 303 dental practitioners. Results: Of respondents, 54.93% curbed the number of patients in the last six months, 34.21% declared no changes, and 10.86% reported an increase; whereas 70.7% of the respondents reported a treatment price increase within the same period (27.96% and 1.32% reported no changes and a decrease, respectively). Of the respondents, 15.5% did not close their businesses during the first wave of the pandemic. Most declared 1 or 2 month break, 30.7% and 34.7%, respectively. Some reported 3, 4, or 5 month breaks (15.84%, 1.32%, and 0.99%, respectively), and only two respondents (0.66%) did not admit patients at all. Headache episodes were more frequent among female dentists before the pandemic; after the pandemic, headache frequency increased among both sexes. Temporomandibular disorders (TMDs) were more frequent among women (p = 0.017). Conclusions: Most Polish dentists followed SARS-CoV-2 recommendations and restricted their practices to admitting only patients with pain or incomplete treatment. Decreased sleep parameters, head, back, and neck pain, were observed. This situation may affect dental health conditions in Polish society over time.
BRAINballs Program Improves the Gross Motor Skills of Primary School Pupils in Vietnam
Authors: Pham Van Han , Wawrzyniak Sara , Cichy Ireneusz , Bronikowski Michał , Rokita Andrzej
Published: February 2021

The purpose of this study was to evaluate the impact of the BRAINballs program on second graders’ gross motor skills in a primary school in Vietnam. A total of 55 students (23 boys and 32 girls) aged seven years participated in the study. The research used the method of a pedagogical experiment and parallel group technique (experimental and control group) with pre- and post-testing. The study was conducted in the school year 2019/2020. The gross motor skills performance was assessed by the Test of Gross Motor Development—2nd Edition. The BRAINballs program was conducted twice a week and combined physical activity with subject-related contents by means of a set of 100 balls with painted letters, numbers, and signs. The results showed that the experimental and control groups improved their motor skills after one school year (p < 0.001). However, the analysis of covariance demonstrated that students from the experimental group, compared to students from the control group, showed significantly better scores in both subtests: locomotor (p = 0.0000) and object control skills (p = 0.0000). The findings of this study show that the BRAINballs program had a positive effect on children’s motor performances and may help to better understand the development of basic motor skills of seven-year-old students in Vietnam.
Work-Fitness Evaluation for Shift Work Disorder
Authors: Jang Tae-Won
Published: February 2021

Shift work disorder (SWD), which is characterized by insomnia and excessive sleepiness related with shift work, is one of the most common health problems in shift workers. Shift work disorder causes insomnia, fatigue, worse work performance, an increased likelihood of accidents, and a poor quality of life. In addition, SWD is associated with decreased productivity and increased economic costs. The correct management of SWD is important to prevent sleep disturbances and maintain work performance in shift workers. To diagnose and evaluate SWD, it is necessary to take detailed medical histories, assess the severity of sleep disturbances, and evaluate shift workers’ sleep using a sleep diary and actigraphy. The work-fitness evaluation should include recommendations on how shift workers can reduce their sleep disturbances and increase work performance, as well as the assessment of work performance. This paper reviews previous research on the evaluation, diagnosis, and management of SWD and summarizes the work-fitness evaluation of SWD.
Factors Associated with Non-Attendance at Dental Preventive Care in Slovak High School Students
Authors: Samohyl Martin , Babjakova Jana , Vondrova Diana , Jurkovicova Jana , Stofko Juraj , Kollar Branislav , Hirosova Katarina , Filova Alexandra , Argalasova Lubica
Published: February 2021

This study aimed to determine the factors associated with the avoidance of dental preventive care in high school students and their parents in the framework of The Youth and Parents Risk Factor Behavior Survey in Slovakia, the ongoing cross-sectional school-based survey of students and their parents or legal representatives. The data were collected using two separate standardized questionnaires: (i) the questionnaire for students (n = 515) and (ii) the questionnaire for parents (n = 681). The study group included 57 high school students (54.4% males) who did not visit the dentist for preventive care in the previous year. The control group included 458 students (35.8% males) who visited a dentist for preventive care at least once in the previous year. A significantly higher number of males (54.4%), older adolescents, and young adults (21.8%; 20.0%) were not visiting dental preventive care regularly. Incomplete family (56.1%), stressful situations at home (17.5%), and feeling unwell were the factors contributing to the avoidance of dental preventive care. More than 34.5% of adolescents and young adults were not visiting either dental preventive care or pediatric preventive care (adjusted odds ratio (AOR) = 5.14; 95% confidence interval (CI) = 2.40, 10.99). Children of divorced mothers and mothers with household income lower than EUR 900 had significantly higher dental care avoidance in bivariate analysis. A significantly higher percentage of fathers from the exposed group were not visiting dental preventive care regularly (47.8%, p < 0.05). The results of the study can be used as an educational intervention step focusing on the parental influence on adolescent and young adults’ behavior and as a challenge for the improvement of dental preventive care in older adolescents and young adults.