bluuebunny/crossref_metadata_2025 huggingface dataset:
Space–time singularities and cosmic censorship conjecture: A Review with some thoughts
Authors: Ong Yen Chin
Published: June 2020

The singularity theorems of Hawking and Penrose tell us that singularities are common place in general relativity. Singularities not only occur at the beginning of the Universe at the Big Bang, but also in complete gravitational collapses that result in the formation of black holes. If singularities — except the one at the Big Bang — ever become “naked,” i.e. not shrouded by black hole horizons, then it is expected that problems would arise and render general relativity indeterministic. For this reason, Penrose proposed the cosmic censorship conjecture, which states that singularities should never be naked. Various counterexamples to the conjecture have since been discovered, but it is still not clear under which kind of physical processes one can expect violation of the conjecture. In this short review, I briefly examine some progresses in space–time singularities and cosmic censorship conjecture. In particular, I shall discuss why we should still care about the conjecture, and whether we should be worried about some of the counterexamples. This is not meant to be a comprehensive review, but rather to give an introduction to the subject, which has recently seen an increase of interest.
Dissipative-type theories for Bjorken and Gubser flows
Authors: Cantarutti Lucas , Calzetta Esteban
Published: June 2020

We use the dissipative-type theory (DTT) framework to solve for the evolution of conformal fluids in Bjorken and Gubser flows from isotropic initial conditions. The results compare well with both exact and other hydrodynamic solutions in the literature. At the same time, DTTs enforce the Second Law of thermodynamics as an exact property of the formalism, at any order in deviations from equilibrium, and are easily generalizable to more complex situations.
Quantum hydrodynamics approach for the research of magnetic skyrmions
Authors: Trukhanova Mariya Iv.
Published: June 2020

We propose a new approach of many-particle quantum hydrodynamics to describe a system of interacting magnetic skyrmions in the external fields. The model is based on the description of skyrmions as a fluid of point-like particles. The equations of many-particle quantum hydrodynamics are obtained for a system of skyrmions with induced dipole moments and charges. The dipole–dipole interaction between dipoles and the Coulomb interaction between charges are taken into account. The influence of quantum effects in the form of the Bohm quantum potential is obtained. The contribution of Magnus effect to the dynamics of dipoles current density is predicted. The electron–skyrmion interactions are considered, based on a two-fluid model of quantum hydrodynamics with separate description of spin-up and spin-down electrons on the background of skyrmion lattice. The proposed model can be further used to study the dynamical effects in a system of skyrmions in the external fields.
Multi-objective optimization of customized bus routes based on full operation process
Authors: Wang Chao , Ma Changxi
Published: June 2020

In order to rationally formulate a customized bus route plan to improve the operation efficiency of customized buses, in view of the problem of ignoring the distance between the boarding area and the alighting area, and setting it as a fixed value when performing custom bus route optimization modeling, as well as solving the problem of multiple custom bus parking lots. This paper proposes a method based on the NSGA-II algorithm using a three-stage hybrid coding method to solve. First, according to real life, the entire operation process of customized buses is divided into four phases. Second, based on the four stages, a multi-objective optimization model of customized bus routes that satisfies multiple parking lots, multiple cars, and multiple boarding and alighting stations is constructed to pursue the minimum total travel time of passengers and minimizes the operating costs of customized bus companies. Third, the NSGA-II algorithm is employed to solve the model, including three-stage hybrid coding, segmented crossover, and segmented mutation operators. Finally, the local road network in Lanzhou City is adopted for simulation research. The results show that it is feasible to use NSGA-II algorithm to solve the problem of customizing bus routes for multiple parking lots, multiple vehicles, and multiple boarding and alighting stations. The research results are of great value for exploring the optimization methods of customized bus routes and improving the operating efficiency of custom buses.
Link community detection based on ensemble learning
Authors: Liu Zhihua , Wang Hongmei , Wang Guishen , Zhou Yu
Published: June 2020

Overlapping community detection is a hot topic in the research of data mining and graph theory. In this paper, we propose a link community detection method based on ensemble learning (LCDEL). First, we transform graph into line graph and construct node adjacency matrix of line graph. Second, we calculate node distance of line graph through a new distance metric and get node distance matrix of line graph. Third, we use PCA method to reduce dimensions of node distance matrix of line graph. Then, we cluster on the reduced node distance matrix by k-means clustering algorithm. Finally, we convert line graph back into original graph and get overlapping communities of original graph with ensemble learning. Experimental results on several real-world networks demonstrate effectiveness of LCDEL method in terms of Normalized Mutual Information (NMI), Extended Modularity (EQ) and F-score evaluation metrics.
Spatio-temporal network modelling and analysis of global strong earthquakes (M
w
≥ 6.0)
Authors: Liu Gang , Fan Qinjin , Li Weile , Scaringi Gianvito , Long Yujie , He Jing , Li Zheng
Published: June 2020

We employ a spatio-temporal network modelling approach to identify possible relations between strong earthquakes and spatial regions worldwide. A global strong earthquake dataset containing 7736 events (M
w
 ≥ 6.0) from 1964 to 2018 is used. Statistical results identify power-law relationships and heavy tail phenomena in the spatial patterns of strong earthquakes. The interactions between regions follow the same law, with a few regions that may be hit by successive strong earthquakes with high probability. Also, we find that the interconnections between regions are mainly related to the succession of events in time, whereas the distribution of events is extremely inhomogeneous in space. This study provides a research prototype for the spatio-temporal analysis of global strong earthquakes, laying a foundation for obtaining insights into the network modelling approach for global strong earthquakes.
Enhanced Interactive 360° Viewing via Automatic Guidance
Authors: Cha Seunghoon , Lee Jungjin , Jeong Seunghwa , Kim Younghui , Noh Junyong
Published: June 2020

We present a new interactive playback method to enhance 360° viewing experiences. Our method automatically rotates the virtual camera of a 360°  panoramic video (360° video) player during interactive viewing to guide the viewer through the most important regions of the video. With this method, the viewer can watch a 360° video with minimum efforts to find important events in a scene both in interactive (e.g., HMD) and less-interactive (e.g., PC and TV) viewing environments. To estimate the importance of each viewing direction, we combine spatial and temporal saliency with cluster-based weighting. A maximum backward cumulative importance volume (MBCIV) is then constructed by accumulating this importance in the video space. During playback, which uses a forward tracing scheme through the MBCIV, the initial optimal path is found based on the viewer’s viewing direction. A smooth path is then derived using penalized curve fitting. Finally, the virtual camera is rotated to follow the path. The experiments and user studies demonstrate that our method allows the viewer to effectively enjoy 360° videos with minimum interaction efforts, or even through a non-interactive display.
Unsupervised Detection of Distinctive Regions on 3D Shapes
Authors: Li Xianzhi , Yu Lequan , Fu Chi-Wing , Cohen-Or Daniel , Heng Pheng-Ann
Published: June 2020

This article presents a novel approach to learn and detect distinctive regions on 3D shapes. Unlike previous works, which require labeled data, our method is unsupervised. We conduct the analysis on point sets sampled from 3D shapes, then formulate and train a deep neural network for an unsupervised shape clustering task to learn local and global features for distinguishing shapes with respect to a given shape set. To drive the network to learn in an unsupervised manner, we design a clustering-based nonparametric softmax classifier with an iterative re-clustering of shapes, and an adapted contrastive loss for enhancing the feature embedding quality and stabilizing the learning process. By then, we encourage the network to learn the point distinctiveness on the input shapes. We extensively evaluate various aspects of our approach and present its applications for distinctiveness-guided shape retrieval, sampling, and view selection in 3D scenes.
Inhomogeneous CTMC Birth-and-Death Models Solved by Uniformization with Steady-State Detection
Authors: Burak Maciej Rafal , Korytkowski Przemyslaw
Published: June 2020

Time-inhomogeneous queueing models play an important role in service systems modeling. Although the transient solutions of corresponding continuous-time Markov chains (CTMCs) are more precise than methods using stationary approximations, most authors consider their computational costs prohibitive for practical application. This article presents a new variant of the uniformization algorithm that utilizes a modified steady-state detection technique. The presented algorithm is applicable for CTMCs when their stationary solution can be efficiently calculated in advance, particularly for many practically applicable birth-and-death models with limited size. It significantly improves computational efficiency due to an early prediction of an occurrence of a steady state, using the properties of the convergence function of the embedded discrete-time Markov chain. Moreover, in the case of an inhomogeneous CTMC solved in consecutive timesteps, the modification guarantees that the error of the computed probability distribution vector is strictly bounded at each point of the considered time interval.
Toward a Theory of Superdense Time in Simulation Models
Authors: Nutaro James
Published: June 2020

We develop a theory of superdense time that encompasses existing uses of superdense time in discrete event simulations and points to new forms that have not previously been explored. A central feature of our development is a set of axioms for superdense time. The sufficiency of these axioms is demonstrated by using them to prove that a general model of a discrete event simulation procedure, expressed in terms of a mathematical system, constitutes a state transition function. Several forms of superdense time, both known and novel, are shown to satisfy the axioms.
Modeling Resources to Simulate Business Process Reliability
Authors: Bocciarelli Paolo , D’Ambrogio Andrea , Giglio Andrea , Paglia Emiliano
Published: June 2020

The combination of process modeling and simulation-based analysis provides a quantitative approach to analyze business processes, and to evaluate design alternatives before committing the required resources, to properly align operations with business strategies, improve operational efficiency, and gain competitive advantage. However, the use of simulation-based analysis is still limited in practice, mainly because it does not exploit process modeling standards and typically addresses performance-related properties only, such as time and cost. This article proposes a methodology that first extends the standard language for process modeling (i.e., BPMN) to introduce a flexible and accurate specification of business process resources, and then exploits the extended process specification to analyze and predict the process behavior by use of a simulation approach that takes into account reliability-related properties, to consider unexpected failures of process resources. The simulation-based analysis is implemented by use of a domain-specific process simulation language that preserves the BPMN execution semantics. An example application is introduced to show the importance of addressing both performance and reliability properties for the simulation-based analysis of business processes.
Testing Relative to Usage Scope
Authors: Miranda Breno , Bertolino Antonia
Published: June 2020

Coverage criteria provide a useful and widely used means to guide software testing; however, indiscriminately pursuing full coverage may not always be convenient or meaningful, as not all entities are of interest in any usage context. We aim at introducing a more meaningful notion of coverage that takes into account how the software is going to be used. Entities that are not going to be exercised by the user should not contribute to the coverage ratio. We revisit the definition of coverage measures, introducing a notion of relative coverage. According to this notion, we provide a definition and a theoretical framework of relative coverage, within which we discuss implications on testing theory and practice. Through the evaluation of three different instances of relative coverage, we could observe that relative coverage measures provide a more effective strategy than traditional ones: we could reach higher coverage measures, and test cases selected by relative coverage could achieve higher reliability. We hint at several other useful implications of relative coverage notion on different aspects of software testing.
Computing Alignments of Well-Formed Process Models using Local Search
Authors: Taymouri Farbod , Carmona Josep
Published: June 2020

The alignment of observed and modeled behavior is an essential element for organizations, since it opens the door for conformance checking and enhancement of processes. The state-of-the-art technique for computing alignments has exponential time and space complexity, hindering its applicability for medium and large instances. In this article, a novel approach is presented to tackle the challenge of computing an alignment for large-problem instances that correspond to well-formed process models. Given an observed trace, first it uses a novel replay technique to find an initial candidate trace in the model. Then a local search framework is applied to try to improve the alignment until no further improvement is possible. The implementation of the presented technique reveals a magnificent reduction both in computation time and in memory usage. Moreover, although the proposed technique does not guarantee the derivation of an alignment with minimal cost, the experiments show that in practice the quality of the obtained solutions is close to optimal.
Construction of Hierarchical Hollow MoS2/Carbon Microspheres for Enhanced Lithium Storage Performance
Authors: Gao Suning , Yang Liangtao , Shao Jie , Qu Qunting , Wu Yuping , Holze Rudolf
Published: June 2020

Hierarchical C@MoS2 hollow spheres assembled from few layer-MoS2 nanosheets coated on both interior and exterior surfaces of hollow carbon spheres (HCSs) have been developed by a modified template method. The polydopamine-derived carbon shell functions as a support with a negatively charged surface resulting in the in situ growth of few layer-MoS2 nanosheets and prevents them from agglomeration with an integrated structure. In addition, the hollow carbon spheres with their mesopores provide sufficient liquid-solid contact area and shorter electron and ion pathways, as well as buffer for volume changes occurring during the charge/discharge process. The prepared C@MoS2 material is characterized by XRD, TGA, BET, Raman, SEM, HRTEM and XPS measurements. When applied as a negative electrode material in LIBs, the C@MoS2 electrode exhibits high reversible gravimetric capacity (1100 mAh·g−1 at 0.1 C), superior rate performance (633 mAh·g−1 at 20.0 C) and superb cycling life (86.0% of its original specific capacity left after 130 cycles).
Analysis of Magnetohydrodynamics Flow of Incompressible Fluids over Oscillating Bottom Surface with Heat and Mass Transfer
Authors: Bulinda Vincent M. , Kang’ethe Giterere P. , Kiogora Phineas R.
Published: June 2020

Analysis of magnetohydrodynamics flow of incompressible fluids over an oscillating bottom surface with heat and mass transfer is discussed. The flow is free convection in nature. Momentum, energy, and concentration equations are obtained for computation of their respective profiles. The unsteady flow two-dimensional governing equations are solved numerically by the explicit finite difference method of the Forward Time Backward Space scheme. The numerical results show that the applied parameters have significant effects on the fluid flow and heat transfer and have been discussed with the help of graphical illustrations.
Performance Evaluation of Cognitive Radio Networks with Imperfect Spectrum Sensing and Bursty Primary User Traffic
Authors: Salameh Osama , Bruneel Herwig , Wittevrongel Sabine
Published: June 2020

In this paper, we introduce a four-dimensional continuous-time Markov chain model to evaluate the performance of cognitive radio networks. In such networks, secondary (unlicensed) users may opportunistically use the frequency channels not currently occupied by primary (licensed) users in order to increase the utilization of the wireless spectrum. Secondary users perform channel sensing before as well as during transmission in order not to interfere with primary users. The proposed model assumes that primary users arrive according to a bursty arrival process and moreover takes the possible occurrence of sensing errors (false alarms and misdetections) into account. Several performance measures including the collision rate between primary and secondary users, the blocking probabilities of primary or secondary users, and the mean delay of secondary users are derived and illustrated through numerical examples. The results show that the system performance strongly depends on the degree of burstiness in the arrival process of primary users. It is also observed that the quality of service of the primary network can be seriously compromised due to misdetection by secondary users.
Point-Symmetric Extension-Based Interval Shannon-Cosine Spectral Method for Fractional PDEs
Authors: Xing Ruyi , Li Yanqiao , Wang Qing , Wu Yangyang , Mei Shu-Li
Published: June 2020

The approximation accuracy of the wavelet spectral method for the fractional PDEs is sensitive to the order of the fractional derivative and the boundary condition of the PDEs. In order to overcome the shortcoming, an interval Shannon-Cosine wavelet based on the point-symmetric extension is constructed, and the corresponding spectral method on the fractional PDEs is proposed. In the research, a power function of cosine function is introduced to modulate Shannon function, which takes full advantage of the waveform of the Shannon function to ensure that many excellent properties can be satisfied such as the partition of unity, smoothness, and compact support. And the interpolative property of Shannon wavelet is held at the same time. Then, based on the point-symmetric extension and the general variational theory, an interval Shannon-Cosine wavelet is constructed. It is proved that the first derivative of the approximated function with this interval wavelet function is continuous. At last, the wavelet spectral method for the fractional PDEs is given by means of the interval Shannon-Cosine wavelet. By means of it, the condition number of the discrete matrix can be suppressed effectively. Compared with Shannon and Shannon-Gabor wavelet quasi-spectral methods, the novel scheme has stronger applicability to the shockwave appeared in the solution besides the higher numerical accuracy and efficiency.
Fluoroscopic Stenting as a Bridge to Surgery versus Emergency Management for Malignant Obstruction of the Colon
Authors: Xue Fan , Lin Feng , Zhou Jun , Feng Ning , Cui You-Gang , Zhang Xu , Yi Yu-Peng , Liu Wen-Zhi
Published: June 2020

Aim. To investigate the feasibility of a SEMS (self-expandable metallic stent) as a bridge to surgery for malignant colonic obstruction. Methods. We retrospectively reviewed 83 patients that were in accordance with inclusion criteria; of these, 33 patients that underwent fluoroscopy-guided SEMS placement followed by elective curative resection were classified as a SEMS group and 50 patients, who received emergency surgery (ES), were classified as an ES group. The clinicopathological characteristics, surgery-related parameters, complications, and three-year survival rate were compared between the two groups. Results. No significant differences between the two groups were observed in any of the clinicopathologic characteristics except for higher preoperative absolute neutrophil count in the ES group (P<0.001). Compared to the ES group, the SEMS group has significantly more cases, which featured a laparoscopic approach (72.7% vs. 14.0%, P<0.001), lower overall stoma rate (0% vs. 34.0%, P<0.001), and lower overall postoperative morbidity (27.3% vs. 56.0%, P=0.010). The oncological outcomes did not differ significantly between the two groups in terms of three-year overall survival (P=0.125). The technical and clinical success rates of stent placement were 91.7% and 100%, respectively. Conclusion. Patients treated with the stent-surgery approach had significant short-term superiorities and similar long-term outcomes, compared to patients who had emergency surgery alone. The SEMS is, therefore, safe and feasible as a bridge to surgery for malignant colonic obstruction.
Pain Management and Its Possible Implementation Research in North Ethiopia: A before and after Study
Authors: Tequare Mengistu Hagazi , Huntzicker James John , Gidey Mhretu Hagos , Zelelew Yibrah Berhe , Abraha Hiluf Ebuy , Tsegay Mehari Abrha , Gebretensaye Kesatea Gebrewahd , Gebre Tesfay Daniel , Sotomayor Julio Gonzalez , Nardos Rahel , Yosses Mary Beth , Cobbs Joshua Edwin , Schmidt Jennifer Pui Ling , Weisman Wendy , Breitner Leslie K.
Published: June 2020

Background. Though there is an effective intervention, pain after surgical intervention is undermanaged worldwide. A systematic implementation is required to increase the utilization of available evidence-based intervention to manage the inevitable pain after surgery. The aim of this research project is to develop a scalable model for managing pain after cesarean section by implementing the World Health Organization’s (WHO) pain management guidelines through a combination of implementation research and quality improvement methods. Methods. We implemented the World Health Organization (WHO) pain management guidelines using effective implementation strategies. First, we conducted a formative qualitative exploration to identify enablers and obstacles. In addition, we took base-line assessment on pain management implementation process and outcome using a checklist prepared from the guideline and an adapted American Pain Outcome assessment tool version 2010, respectively. Then, we integrated the guidelines into the existing practice by using collaborative iterative learning strategy. We analyzed the data by Statistical Packages for Social Sciences (SPSS) version 21. We compared the before and after data using chi-squared and Fischer’s exact test. A change in any measurement was considered as significant at p value 0.05. Result. We collected data from 106 mothers before and 110 mothers after intervention implementation. We successfully integrated pain as a fifth vital sign in more than 87% (p value <0.001) of patient, and fidelity was approximately 59% (p value <0.001). In addition, we significantly improved pain outcome measures after the implementation of the intervention. Conclusion and Recommendations. A systematic approach to implement pain management guidelines was successful. We recommend the ward sustain these gains and that hospital, the region, and the nation to replicate the success.
Comparison of Postoperative Pain and Appetite in Pediatric Patients Undergoing Monopolar Tonsillotomy and Cold Steel Tonsillectomy
Authors: El Sayed Ahmad Youssef , Nehme Jade , Moukarzel Nabil
Published: June 2020

Objectives. Adenotonsillectomy (AT) is amongst the most widely performed pediatric surgeries in the United States (US) and the whole world. AT includes two major surgical techniques: total tonsillectomy (TT) and partial tonsillectomy (PT). Several studies have been conducted to evaluate the difference between TT and PT and assess the comparative effectiveness, benefits, and sequelae between both. In Lebanon, very few studies were done tackling this issue and assessing its sequelae on the pediatric population. Methods. A prospective study was conducted including pediatric patients aged between 2 and 9 years, who were admitted for partial tonsillectomy (PT) or total tonsillectomy (TT) in 2018. An estimated number of children included were 50: 25 patients underwent PT and 25 patients underwent TT. Patients were sent home on day 1 post-op with a questionnaire that evaluates the following over the first 10 days post-op: pain using the Wong–Baker Faces Pain Rating Scale and the “Parents Postoperative Pain Measure” (PPPM) questionnaire, and appetite using the visual analogue scale (VAS). Results. Patients in the PT group and in the TT group had no demographical differences in terms of age, BMI, exposure to smoking, area of living, and attending a day care center. Comparison between PT and TT revealed a significant difference in both pain and appetite scales. Patients who underwent PT had significantly lower PPPM scores on the 1st, 2nd, 4th, 5th, 6th, and 10th day after surgery compared to the TT patients. Further validation was revealed by the Wong–Baker Faces Pain Rating Scale, showing that the PT surgery group experienced significantly less postoperative pain compared to the TT surgery group. Assessing the appetite using the visual analogue scale favored PT over TT. Comparisons revealed that most PT patients returned to their normal eating habits starting at day 4 while this was applicable in the TT group at day 10. Postoperative pain improved from day 1 to day 10 in both surgical groups. Conclusion. In conclusion, the recovery process after the PT surgery causes less postoperative morbidity, thus an earlier return to normal activity compared to the TT. The patients of the latter group are affected by more pain and less appetite over the first 10 days after the surgery.
Existence Theory and Novel Iterative Method for Dynamical System of Infectious Diseases
Authors: Ali Gauhar , Nazir Ghazala , Shah Kamal , Li Yongjin
Published: June 2020

This manuscript is devoted to investigate qualitative theory of existence and uniqueness of the solution to a dynamical system of an infectious disease known as measles. For the respective theory, we utilize fixed point theory to construct sufficient conditions for existence and uniqueness of the solution. Some results corresponding to Hyers–Ulam stability are also investigated. Furthermore, some semianalytical results are computed for the considered system by using integral transform due to the Laplace and decomposition technique of Adomian. The obtained results are presented by graphs also.
Acute Effect of a Protein Supplement on Targeted Plasma Amino Acid Profile among Healthy Asian Indians: A Randomized Controlled Trial
Authors: Kurien Ammu , Sharma Nidhi , Marathe Madhavi , Joshi Nandan , Selvam Sumithra , Devi Sarita , Sambashivaiah Sucharita
Published: June 2020

Background. Indians have a poor protein intake in terms of quantity as well as quality because of their predominantly cereal-based diet. However, there is limited information on circulatory amino acid levels in healthy Indians. Herein, we evaluated the acute effect of a protein supplement on the plasma levels of essential amino acids (EAAs) in healthy Indian adults, using targeted EAA analysis. Methods. In this double-blind, randomized, crossover study, 20 healthy Indian adults were randomized to receive the test protein supplement (treatment arm, n = 10) or placebo (control arm, n = 10) with milk, after overnight fasting. After 7 days, the participants returned for the crossover treatment. Blood samples were collected at baseline and at 60 and 120 min after protein/placebo consumption. Plasma EAA levels were estimated using liquid chromatography-tandem mass spectrometry. Repeated measures ANOVA was performed to assess the effect of treatment on EAA levels. P values < 0.05 were considered statistically significant. Results. At baseline, mean plasma levels did not differ significantly between the two arms for any of the EAAs. In the treatment arm, the mean levels of all EAAs increased significantly from baseline to 60 min (P<0.01), with no significant change from 60 to 120 min. There was no significant change in amino acid levels in the control arm. The magnitude as well as percentage of increase from baseline to 60 min was significantly greater in the treatment arm than in the control arm for all EAAs. Conclusion. Compared to placebo, protein supplement increased circulatory amino acid levels in healthy Indians. The observed increase in EAA levels and its role in conjunction with exercise in both healthy and diseased states need to be further evaluated. This is the first dataset exploring targeted EAA profiles and the effect of a protein supplement among healthy Indians. The clinical trial is registered with CTRI/2018/12/016777.
A Study on Correlation of Traffic Accident Tendency with Driver Characters Using In-Depth Traffic Accident Data
Authors: Hu Lin , Bao Xingqian , Wu Hequan , Wu Wenguang
Published: June 2020

Traffic accidents are often related to the driver’s driving behavior, which is mainly decided by his or her characters. In order to explore the correlation of traffic accident risk with driver characters, the age, driving experience, and driving style were statistically analyzed based on the China In-Depth Accident Study (CIDAS) database. Taking the number of casualties in the accident as evaluation indicators, the grey cluster analysis was used to classify the drivers into four accident risk ranks: low, medium to low, medium to high, and high. The results show that drivers aged 18–30 years are more likely to induce accidents; drivers with 6–10 years of driving experience have the highest risk to accidents, followed by drivers with 4-5 years of driving experience; and the driving style is also highly correlated with accident risk tendency.
Banded Sleeve Gastrectomy Improves Weight Loss Compared to Nonbanded Sleeve: Midterm Results from a Prospective Randomized Study
Authors: Gentileschi Paolo , Bianciardi Emanuela , Siragusa Leandro , Tognoni Valeria , Benavoli Domenico , D’Ugo Stefano
Published: June 2020

Background. Weight regain after laparoscopic sleeve gastrectomy (LSG) is nowadays a growing concern. Sleeve dilatation and loss of food restriction is considered the main mechanism. The placement of a silicon ring around the gastric tube seems to give benefits in the short term. We report the results of a randomized study comparing LSG and laparoscopic banded sleeve gastrectomy (LBSG) over a 4-year follow-up. Objectives. To evaluate the efficacy of banded sleeve gastrectomy compared to standard sleeve in the midterm. Methods. Between 01/2014 and 01/2015, we randomly assigned 50 patients to receive one of the two procedures. Patients’ management was exactly the same, apart from the band placement. We analyzed differences in weight loss, operative time, complication rate, and mortality, with a median follow-up of 4 years. Results. Twenty five patients were assigned to receive LSG (Group A) and 25 LBSG (Group B). The mean preoperative BMI (body mass index) was 47.3 ± 6.58 kg/m2 and 45.95 ± 5.85 kg/m2, respectively. There was no significant difference in the operative time. No intraoperative or postoperative complications occurred. At 12-month follow-up, the mean BMI was 29.72 ± 4.40 kg/m2 in Group A and 27.42 ± 4.47 kg/m2 in Group B (p=0.186). After a median follow-up of 4 years, the mean BMI in Group B was significantly lower than Group A (24.10 ± 4.52 kg/m2 vs 28.80 ± 4.62 kg/m2; p=0.00199). Conclusions. LBSG is a safe procedure, with no impact on postoperative complications. The banded sleeve showed a significant greater weight loss in the midterm follow-up. Considering the issue of weight regain observed after LSG, the placement of a perigastric ring during the first procedure may be a strategy to improve the results. This trial is registered with NCT04228185.
Mathematical Oncology Comes to the Clinic: A Data-Driven Treatment for Financial Toxicity?
Authors: Triche Timothy J.
Published: June 2020

Over the past two decades, progress in tumor immunology and targeted therapy has reshaped oncology, and in many cases, reshaped the course of once-intractable diseases. Yet the cost of its clinical manifestation has created a disease of its own: “financial toxicity,” the burden of drugs such as imatinib, where a year's supply can easily cost as much as a house. Equally rapid progress in mathematical oncology over this time period has often come in the form of fundamental, rather than applied, advances. However, in new work by Hähnel and colleagues, we can see the outlines of a viable treatment for financial toxicity: precise, dynamic, clinically validated, and immune-aware models, able to accurately identify patients who remain disease-free in the months and years after discontinuing effective, but pricey, targeted therapies.

See related article by Hähnel et al., p. 2394
Immuno-Interception for Patients with High-Risk Cancer
Authors: Umar Asad , Loomans-Kropp Holli A.
Published: June 2020

Cancer immune-interception for prevention of recurrence in patients with high-risk familial cancer like Muir–Torre syndrome or Lynch syndrome using immune checkpoint blockade inhibitors is a promising approach. Albeit, as described in a case report by Pollak and colleagues in the April 2020 issue of Cancer Prevention Research, it has the potential to be used as immune-interceptive with alternative dosing regimens for cancers with microsatellite instability. The combination of additional cancer preventive and immunopreventive approaches, such as vaccines and minimal dose of immune checkpoint blockade inhibitors, is another unexplored modality for cancer interception in high-risk individuals.
Optimization of wind energy conversion systems – an artificial intelligent approach
Authors: Koay Ying Ying , Tan Jian Ding , Koh Siaw Paw , Chong Kok Hen , Tiong Sieh Kiong , Ekanayake Janaka
Published: June 2020

The environmentally friendly wind energy conversion system has become one of the most studied branches of sustainable energy. Like many other power generator, maximum power point tracking is an easy yet effective way to boost the efficiency of the conversion system. In this research, a modified Electromagnetism-like Mechanism Algorithm (EM) is proposed for the maximum power point tracking (MPPT) scheme of a micro-wind energy conversion system (WECS). In contrast with the random search steps used in a conventional EM, modified EM is enhanced with a Split, Probe, and Compare (SPC-EM) feature which ensures solutions with higher accuracies quicker by not having to scrutinize the search in details at the beginning stages of the iterations. Experiments and simulations are carried to test the SPC-EM in tracking the maximum power point under different wind profiles. Results indicate that the performance of the modified EM showed significant improvement over the conventional EM in the benchmarking. It can thus be concluded that based on the simulations, the SPC-EM performs well as an MPPT scheme in a micro-WECS.
Buck converter optimization using P&O algorithm for PV system based battery charger
Authors: Abidin Zainul , Muttaqin Adharul , Maulana Eka , Ramadhan M. Gilang
Published: June 2020

In this research, battery charger based on Photovoltaic (PV) system consists of buck converter as useful PV module interface was fabricated. Since output power of PV module changes quickly due to changing solar radiation, optimization is required. One of the easy and cheap optimization techniques is by implementing Perturb and Observe (P&O) algorithm for controlling switch of the buck converter. The P&O algorithm tracks maximum power point by generating suitable duty cycle for switching of the buck converter. The objective of this paper is to present the experimental proof of the P&O algorithm implementation in optimizing performance of the buck converter. The experimental results prove that the P&O algorithm can optimize the work of the buck converter and support shorter charging time by producing higher output voltage and power.
Transmission line fault identification and classification with integrated FACTS device using multiresolution analysis and naïve bayes classifier
Authors: Aker Elhadi Emhemed , Othman Mohammad Lutfi , Aris Ishak , Wahab Noor Izzri Abdul , Hizam Hashim , Emmanuel Osaj
Published: June 2020

This paper is present a novel approach for solving the pending under-reach problem encountered by distance relay protection scheme in the 3rd zones protection coverage for a midpoint STATCOM compensated transmission lines. The propose transmission line model is develop in Matlab for analyzed feature extraction using Discrete Wavelet multiresolution analysis approach. Extracted feature from standard deviation and entropy energy contents of SLG transient faults current at location beyond the integrated STATCOM used for machine learning algorithm model building using WEKA software. The Naïve Bayes classifier model perform best with robustness prediction and detection of faults with quick convergence even with less training data. The outperformance of the proposed classifier has been 100 % for the relay algorithm modification for under-reach problem elimination in 3rd zones protection coverage.
Modeling of single phase off-grid inverter for small standalone system applications
Authors: Tan Rodney H.G. , Chuin Chong Boon , Solanki Sunil Govinda
Published: June 2020

This paper presents the detail circuitry modeling of single phase off-grid inverter for small standalone system applications. The entire model is developed in MATLAB/Simulink platform using circuitry model. This off grid inverter consists of a high frequency DC-DC step up converter cascaded with a full bridge PI control voltage source inverter using SPWM modulation with LC filter to produce sine wave output. This is a common design used in many small commercial off-grid inverter. This off-grid inverter model is capable to produce AC sinewave output voltage at 230 V 50 Hz up to 1 kW power from a 48 V DC lead acid battery source. The AC sine wave output waveform achieved a voltage Total Harmonic Distortion (THD) of less than 1 % which is almost a pure sine wave. The conversion efficiency performance of the off-grid inverter achieved more than 94 %. The performance of the model is validated by real commercial off-grid inverter. The performance validation experiment shows that the off-grid inverter Simulink model conversion efficiency and THD performance are comparable to the commercial off-grid inverter. This model contributes to assist small to medium standalone system load and battery sizing design with greater accuracy.
Are Higher Operator Volumes for Unprotected Left Main Stem Percutaneous Coronary Intervention Associated With Improved Patient Outcomes?
Authors: Kinnaird Tim , Gallagher Sean , Anderson Richard , Sharp Andrew , Farooq Vasim , Ludman Peter , Copt Samuel , Curzen Nick , Banning Adrian , Mamas Mamas
Published: June 2020

Background:

The relationship between operator volume and survival after unprotected left main stem percutaneous coronary intervention (uLMS-PCI) is poorly defined.

Methods:

Data from the British Cardiovascular Intervention Society national PCI database were analyzed for all uLMS-PCI procedures performed in England and Wales between 2012 and 2014 and 4 quartiles of annualized uLMS-PCI volume (Q1–Q4) generated. Individual logistic regressions were performed for 12-month mortality to quantify the independent association between operator quartile and outcomes.

Results:

In total, 6724 uLMS-PCI procedures were analyzed with a negatively skewed distribution and an annualized median of 3 procedures per year. Operator volume ranged from 1 to 54 uLMS-PCI procedures/year. Within Q1, 347 operators performed a median of 2 procedures/year (interquartile range, 1–3); in Q2, 134 operators performed a median of 5 procedures/year (interquartile range, 4–6); in Q3, 59 operators performed a mean of 10 procedures/year (interquartile range, 8–12); and in Q4, 29 operators performed a mean of 21 procedures/year (interquartile range, 17–29). Higher volume operators undertook uLMS-PCI in patients with greater comorbid burden and performed more complex procedures compared with lower operator volumes. Adjusted in-hospital survival (odds ratio, 0.39 [95% CI, 0.24–0.67];
P
<0.001), in-hospital major adverse cardiac and cerebral events (odds ratio, 0.41 [95% CI, 0.27–0.62];
P
<0.001), and 12-month survival (odds ratio, 0.54 [95% CI, 0.39–0.73];
P
<0.001) were lower in Q4 operators compared with Q1 operators. A close association between operator volume/case and superior 12-month survival was observed (
P
<0.001). The lower volume threshold of minimum operator uLMS-PCI volume associated with improved survival was ≥16 cases/year.

Conclusions:

These data suggest that operator volume is an important factor in determining outcome after uLMS-PCI.
l
-Tryptophan–Induced Vasodilation Is Enhanced in Preeclampsia
Authors: Broekhuizen Michelle , Klein Theo , Hitzerd Emilie , de Rijke Yolanda B. , Schoenmakers Sam , Sedlmayr Peter , Danser A.H. Jan , Merkus Daphne , Reiss Irwin K.M.
Published: June 2020

l
-tryptophan induces IDO (indoleamine 2,3-dioxygenase) 1–dependent vasodilation. IDO1 is expressed in placental endothelial cells and downregulated in preeclampsia. Hypothesizing that this may contribute to diminished placental perfusion, we studied
l
-tryptophan–induced vasodilation in healthy and early-onset preeclampsia placental arteries, focusing on placental kynurenine pathway alterations. Despite IDO1 downregulation, kynurenine pathway metabolite concentrations (measured with ultra-performance liquid chromatography-tandem mass spectrometry) were unaltered in preeclamptic versus healthy placentas. Most likely, this is due to enhanced
l
-tryptophan uptake, evidenced by increased
l
-tryptophan levels in preeclamptic placentas. Ex vivo perfused cotyledons from healthy and preeclamptic placentas released similar amounts of
l
-tryptophan and kynurenine pathway metabolites into the circulations. This release was not altered by adding
l
-tryptophan in the maternal circulation, suggesting that
l
-tryptophan metabolites act intracellularly. Maternally applied
l
-tryptophan did appear in the fetal circulation, confirming placental passage of this essential amino acid. After in vitro incubation of placental arteries with IDO1-upregulating cytokines interferon-γ and tumor necrosis factor-α,
l
-tryptophan induced vasodilation. This vasodilation was attenuated by both IDO1 and nitric oxide (NO) synthase inhibitors. Despite IDO1 downregulation,
l
-tryptophan–induced relaxation was enhanced in preeclamptic versus healthy placental arteries. However, cytokine stimulation additionally upregulated the LAT (
l
-type amino acid transporter) 1 in preeclamptic placental arteries only. Vasodilation to the lipophilic, transporter independent ethyl ester of
l
-tryptophan was reduced in preeclamptic versus healthy placental arteries, in agreement with reduced IDO1 expression. In conclusion,
l
-tryptophan induces IDO1- and NO-dependent relaxation in placental arteries, which is determined by
l
-tryptophan uptake rather than IDO1 expression. Increased
l
-tryptophan uptake might compensate for reduced IDO1 expression in preeclamptic placentas.
Prior Coronary Artery Bypass Graft Surgery and Outcome After Percutaneous Coronary Intervention: An Observational Study From the Pan‐London Percutaneous Coronary Intervention Registry
Authors: Rathod Krishnaraj S. , Beirne Anne‐Marie , Bogle Richard , Firoozi Sam , Lim Pitt , Hill Jonathan , Dalby Miles C. , Jain Ajay K. , Malik Iqbal S. , Mathur Anthony , Kalra Sundeep Singh , DeSilva Ranil , Redwood Simon , MacCarthy Philip A. , Wragg Andrew , Smith Elliot J. , Jones Daniel A.
Published: June 2020

Background

Limited information exists regarding procedural success and clinical outcomes in patients with previous coronary artery bypass grafting (CABG) undergoing percutaneous coronary intervention (
PCI
). We sought to compare outcomes in patients undergoing
PCI
with or without
CABG
.

Methods and Results

This was an observational cohort study of 123 780 consecutive
PCI
procedures from the Pan‐London (
UK
)
PCI
registry from 2005 to 2015. The primary end point was all‐cause mortality at a median follow‐up of 3.0 years (interquartile range, 1.2–4.6 years). A total of 12 641(10.2%) patients had a history of previous
CABG
, of whom 29.3% (n=3703) underwent
PCI
to native vessels and 70.7% (n=8938) to bypass grafts. There were significant differences in the demographic, clinical, and procedural characteristics of these groups. The risk of mortality during follow‐up was significantly higher in patients with prior
CABG
(23.2%;
P
=0.0005) compared with patients with no prior
CABG
(12.1%) and was seen for patients who underwent either native vessel (20.1%) or bypass graft
PCI
(24.2%;
P
<0.0001). However, after adjustment for baseline characteristics, there was no significant difference in outcomes seen between the groups when
PCI
was performed in native vessels in patients with previous
CABG
(hazard ratio [HR],1.02; 95%
CI,
0.77–1.34;
P
=0.89), but a significantly higher mortality was seen among patients with
PCI
to bypass grafts (HR,1.33; 95%
CI,
1.03–1.71;
P
=0.026). This was seen after multivariate adjustment and propensity matching.

Conclusions

Patients with prior
CABG
were older with greater comorbidities and more complex procedural characteristics, but after adjustment for these differences, the clinical outcomes were similar to the patients undergoing
PCI
without prior
CABG
. In these patients, native‐vessel
PCI
was associated with better outcomes compared with the treatment of vein grafts.
Safety, tolerability and efficacy of LEGA-Kid® mechanical percussion device versus conventional chest physiotherapy in children: a randomised, single-blind controlled study
Authors: Hue YL , Lum LCS , Ahmad SH , Tan SS , Wong SY , Nathan AM , Eg KP , Choon MBMM
Published: June 2020

INTRODUCTION Chest physiotherapy (CPT) may benefit children aged below five years who suffer from lower respiratory tract infection (LRTI). However, its effects depend on the technique used. This study aimed to determine whether mechanical CPT using the LEGA-Kid® mechanical percussion device is superior to manual CPT in children with LRTI. METHODS Children aged five months to five years who were admitted and referred for CPT from January to April 2017 were randomised to either manual CPT or mechanical CPT with LEGA-Kid. Outcomes measured before intervention and two hours after intervention were respiratory rate (RR), oxygen saturation and modified Respiratory Distress Assessment Instrument (mRDAI) score. RESULTS All 30 enrolled patients showed significant reduction in post-intervention RR and mRDAI scores. There was an 8% reduction in RR for the manual CPT group (p = 0.002) and a 16.5% reduction in the mechanical CPT group (p = 0.0001), with a significantly greater reduction in the latter (p = 0.024). mRDAI scores decreased by 2.96 in the manual group (p = 0.0001) and 3.62 in the mechanical group (p = 0.002), with no significant difference between the groups. There was no significant improvement in oxygen saturation, and no adverse events were observed after CPT. CONCLUSION Children receiving both manual and mechanical CPT showed improvements in respiratory distress symptoms, with no adverse effects. A combined strategy of nebulised hypertonic saline followed by CPT for LRTI removes airway secretions and results in improvements in moderately severe respiratory distress. The LEGA-Kid mechanical CPT method is superior to manual CPT in reducing the RR.