bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi-objective Optimization of Spectrum Sensing and Power Allocation Based on Improved Slime Mould Algorithm
Authors: Sun Jianan , Guo Bin , Hu Yanfei , Zhang Yiheng
Published: July 2021

In order to improve the throughput of sub-users of cognitive radio networks and reduce the interference to primary users, firstly, we consider the spectrum sensing time, decision threshold, and power allocation factors of joint sub-users, and construct the average network throughput and average interference as a multi-objective optimization problem, and secondly, propose a multi-objective optimization algorithm based on improved sticky bacterium algorithm (SMA) to model and solve this problem to obtain the best the sensing time, decision threshold and power. Finally, the proposed method is compared with the NSGA-II algorithm, and the simulation results show that the proposed method can effectively search for the optimal solutions of the spectrum sensing parameters to maximize the average network throughput and minimize the average interference.
A Comparative Study on the Influence of Artificial Intelligence Robot Distribution and Traditional Logistics Distribution Mode
Authors: Zhang Xiaolei
Published: July 2021

With the increasing level of intelligence of logistics enterprises in China, the mode of artificial intelligent logistics distribution has become a new strategy for the development of modern logistics industry. In the logistics industry of artificial intelligence, logistics robot has occupied the market and become the key link of logistics distribution. It is of great significance to study the distribution mode of artificial intelligence robot. With the development of our national economy and the improvement of people’s living standard, the demand for logistics service quality and distribution efficiency is higher and higher. At present, most enterprises in our country abandon the traditional manpower distribution operation mode. This paper expounds the basic concepts of “artificial intelligence” and “intelligent robot” through the literature research method and the research method of combining theory with practical cases, and obtains the cognition of the current technology of intelligent logistics by collecting, processing and sorting the relevant documents. The emergence of artificial intelligence makes large amount of data fast and accurate, while artificial intelligence robot makes logistics management system, object transportation, distribution and order quantity processing intelligent, and produces the integration of production, the production chain is greatly reduced, the communication between logistics enterprises and intelligent robots is closer, the corresponding cost can be greatly reduced, and the enterprise can manage and operate effectively.
Research on the hyper-heuristic of Sub-domain Elimination Strategies based on Firefly Algorithm
Authors: Sun Mingquan , Xing Bangsheng , Yang Daolong
Published: July 2021

In this study, a hyper-heuristic named Sub-domain Elimination Strategies based on Firefly Algorithm (SESFA) is proposed. First, a typical hyper-heuristic is usually using the high-level strategy selection or the combination of the low-level heuristics to obtain a new hyper-heuristic, each round of optimization process is carried out in the whole problem domain. However, SESFA evaluates the problem domain through the feedback information of the meta-heuristic at the lower level, eliminating the poor performance areas, and adjusting the underlying heuristic or adjusting the algorithm parameters to improve the overall optimization performance. Second, the problem domain segmentation function in SESFA can reduce the complexity of the objective function within a single sub-domain, which is conducive to improving the optimization efficiency of the underlying heuristic. Further, the problem domain segmentation function in SESFA also makes there is no direct correlation between different sub-domains, so different underlying heuristics can be adopted in different sub-domains, which is beneficial to the realization of parallel computing. Comparing SESFA with Firefly Algorithms with five standard test functions, the results show that SESFA has advantages in precision, stability and success rate.
An Algorithm for Target Tracking of the Car in Accident
Authors: Zhang Siyuan , Liu Yunqing , Dai Yile
Published: July 2021

At present, the target tracking algorithm for the video of the vehicle involved in the accident is not perfect, which causes the target to rotate and the target is blocked, and the tracking effect is not good. This paper uses a CamShift tracking algorithm that combines HLBP feature matching and unscented Kalman filtering. Firstly, the vehicle features are extracted through the algorithm to obtain more accurate features, thereby reducing the interference caused by the target rotation on the feature extraction. Secondly, the degree of occlusion of the target is judged by the Bhattacharyya distance, and finally the UKF algorithm is used to predict the target position. The vehicle efficiently solve the problem of poor tracking performance when the target is occluded. Experiments have proved that, in the actual application of tracking the accident vehicle, the algorithm can effectively reduce the influence of external factors on the tracking effect, and the tracking accuracy is greatly improved.
Research on Face Recognition Algorithm Based on Convolutional Nerve
Authors: Fang Yunqian
Published: July 2021

Facial expression can truly reflect people’s inner activities, human emotions can be fully reflected through the expression, facial expression recognition in the field of artificial intelligence has important research significance, in daily life also has its application value. At present, facial expression recognition technology has become a very promising frontier technology, but also the current research focus in the field of computer vision.

In this paper, facial expression recognition based on convolution neural network is studied. The concrete work has the following several parts: For the part of face detection, this paper introduces the common methods of knowledge-based rules, feature-based, template-based matching, and statistical model-based, and V-J detector is used for face detection in this paper. In the part of expression recognition, we study the recognition of happiness, sadness, anger, depression, fear and surprise by convolution neural network. This paper uses keras to build a deep learning framework. The neural network consists of volume base layer, pool layer, activation layer and full connection layer. The classifier uses softmax. Using the image data in the standard database as input, after the processing of each layer in the neural network, and finally outputting the probability corresponding to six expressions through softmax, it is generally believed that the expression with the highest probability is the facial expression in the input image.
Application Research of VR Technology in Product Design
Authors: Min Song
Published: July 2021

At present, VR technology has been widely used in R&D and manufacturing of product design projects because of its many advantages. How to further improve the application effect of VR technology in product design practice projects has become one of the research hotspots in the design field in recent years. Based on this, this paper explores the application of VR technology in product design. Firstly, it introduces the basic situation of VR technology. Then, taking the design of leisure and entertainment products in public facilities as an example, it discusses the basic application process of VR technology. Finally, it looks forward to the future development of VR technology based on the shortcomings of VR technology in product design.
An Empirical Study of Online Terminology Translation Retrieval:Using Search Engines as a Tool
Authors: Wang Zheng
Published: July 2021

Online search engines and other computer-aided tools are playing an increasingly important role in technical translation, especially in the translation of out-of-vocabulary new terms. Dictionaries, at times, prove to be of little help to term translation where out-of-vocabulary terms rely on polysemy for heuristic effects. This paper explores the role of online search engines in terminology translation by analyzing the effectiveness of four terminology translation extraction methods which utilize online search engines as search tools, thereby generating suggestions on how to use search result for reference. An experiment with some new terms was conducted to examine the effectiveness of each method. This study revealed that template-based term translation extraction and dictionary-based translation extraction have the highest accuracy rate of 86% and 89% respectively while semantic prediction search method is the most flexible method with the highest retrieval rate of 95% although its results are not always accurate. Therefore, a verification model was proposed, which utilizes quantitative-and-qualitative context analysis to verify the accuracy of translation results obtained from a search engine.
Research on Intelligent Fault Diagnosis of Servo Hydraulic Drawing Cushion
Authors: Yu Zikou , Duan Yongyong , Wu Zongling , Wang Yuhang
Published: July 2021

The drawing cushion of press line in the press workshop of the whole car factory has been extensively upgraded from air cushion to hydraulic drawing cushion. The hydraulic drawing cushion is more accurate than the drawing force of the air cushion, however, the hydraulic drawing cushion is a complex of mechanical, hydraulic, Motion Control and detection technology, and coupled with the press, which makes the fault diagnosis of the hydraulic drawing cushion more difficult. This paper mainly introduces the problems of the coordination among the three systems of mechanical, hydraulic and electronic control of Rexroth Company’s servo-hydraulic drawing cushion and its intelligent fault diagnosis method.
A Target Detection and Evaluation Method for Safety Protection Equipment
Authors: Qiu Jianzhong , Wu Jun , Wan Guoyong , Huang Pengcheng , Zhou Tingting
Published: July 2021

The existing safety detection methods are not sufficient to achieve real-time accurate detection, and cannot perform real-time safety assessment. Taking the construction site as an example, this paper proposes a safety equipment wear detection method based on the joint constraint of linear distance and angle, and proposes the idea of establishing a knowledge database of safety protection equipment wear behavior, and proposes a safety factor evaluation model. In this paper, convolutional neural networks are used to identify the construction personnel and safety equipment in two basic poses, and the linear distance and deflection angle of the regional center point coordinates are used to jointly determine the wearing status of the safety equipment. The generated result matches the safety information knowledge base to obtain the final test results. We obtained the real-time safety factor of the construction personnel by correlating the detection results with the actual scene. Finally, the method used in the article is summarized and prospected.
Segmentation of Pulmonary Nodules Based on BBClstm Unet
Authors: Wang Xi , Li Mingqiu , Yang Ji
Published: July 2021

To solve the problem of insufficient segmentation accuracy caused by the failure of UNET model to make full use of the weight relationship and semantic information between coding layers in lung nodule image segmentation, a lung nodule segmentation method based on BBClstm-Unet is proposed. In this method, parallel attention module is used to complete the information coding of a larger range of pulmonary nodules image and reset the weight of sampling correlation channel information. Bconvlstm structure is used to combine feature mapping, and forward and backward output sampling are fused to obtain the final segmentation result. At the same time, hybrid loss function is used to alleviate the class imbalance problem. The experimental results show that the average dice value of BBClstm-Unet network on luna16 data set reaches 90.83%, which is better than the original UNET network.
Driver Fatigue Detection Based on Parallel Neural Network
Authors: Yang Ji , Li Mingqiu , Wang Xi , Lu Jiafeng
Published: July 2021

Aiming at the problem that the existing fatigue driving detection methods cannot make full use of eye features and semantic information, a driver eye fatigue detection method based on parallel neural network is proposed. This method detects human faces through a multi-task cascaded convolutional network, determines the driver’s eye area according to the face ratio relationship, uses the parallel structure of the convolutional neural network and the residual network to recognize the eye state opening and closing, and according to PERCLOS the criterion is to judge the fatigue state. The experimental results show that the method has a high accuracy rate and can effectively detect the fatigue driving state.
Primary Frequency Regulation of Intelligent Building-type Virtual Power Plant
Authors: Cui Yong , Xiao Fei , Gu Jun , Wang Weihong , Cao Liang , Zhan Gui , Yin Shuangrui , Chen Minyu , Ai Qian
Published: July 2021

In order to cope with the impact of intelligent building-type virtual power plant on system frequency, this paper proposes a primary frequency control strategy. Firstly, a typical demand-side resource model of intelligent building-type virtual power plant is established, which considers the travel uncertainty of electric vehicles and resident’s comfort preference. Secondly, the control parameters of electric vehicles and air-conditioning loads are designed respectively, and a control strategy based on variable coefficient droop control is proposed. Finally, a simulation example verifies the effectiveness of the primary frequency regulation strategy, which can effectively reduce system frequency fluctuations while ensuring user demand.
Betting on the best case: higher end warming is underrepresented in research
Authors: Jehn Florian U , Schneider Marie , Wang Jason R , Kemp Luke , Breuer Lutz
Published: July 2021

We compare the probability of different warming rates to their mentions in IPCC reports through text mining. We find that there is a substantial mismatch between likely warming rates and research coverage. 1.5 °C and 2 °C scenarios are substantially overrepresented. More likely higher end warming scenarios of 3 °C and above, despite potential catastrophic impacts, are severely neglected.
Reducing CO2emissions by targeting the world’s hyper-polluting power plants*
Authors: Grant Don , Zelinka David , Mitova Stefania
Published: July 2021

Combusting fossil fuels to produce electricity is the single largest contributor to sector-level, anthropogenic carbon pollution. Because sector-wide policies are often too unwieldy to implement, however, some researchers have recommended reducing electricity-based CO2emissions by targeting the most extreme emitters of each nation’s electricity industry. Here, we use a unique international data source to measure national disproportionalities in power plant CO2emissions and estimate the fraction of each country’s electricity-based CO2emissions that would be reduced if its most profligate polluters lowered their emission intensities, switched to gas fuels, and incorporated carbon capture and storage systems. We find that countries’ disproportionalities vary greatly and have mostly grown over time. We also find that 17%–49% of the world’s CO2emissions from electricity generation could be eliminated depending on the intensity standards, fuels, or carbon capture technologies adopted by hyper-emitting plants. This suggests that policies aimed at improving the environmental performance of ‘super polluters’ are effective strategies for transitioning to decarbonized energy systems.
A mapping between the spin and fermion algebra
Authors: Meier Felix , Waltner Daniel , Braun Petr , Guhr Thomas
Published: July 2021

We derive a formalism to express the spin algebra

s
u

(

2

)

in a spin s representation in terms of the algebra of L fermionic operators that obey the canonical anti-commutation relations. We also give the reverse direction of expressing the fermionic operators as polynomials in the spin operators of a single spin. We extend here to further spin values the previous investigations by Dobrov (2003 J. Phys. A: Math. Gen.
36 L503) who in turn clarified on an inconsistency within a similar formalism in the works of Batista and Ortiz (2001 Phys. Rev. Lett.
86 1082). We then consider a system of L fermion flavors and apply our mapping in order to express it in terms of the spin algebra. Furthermore we investigate a possibility to simplify certain Hamiltonian operators by means of the mapping.
Removing invasive conifers - considerations, complexity and costs
Authors: Edwards Peter , Sprague Rowan , Stahlmann-Brown Philip
Published: July 2021

Invasive conifers are a significant problem in countries such as New Zealand, requiting a substantial investment to bring them under control. One of the critical elements of controlling invasive conifers is operational planning—determining where to control them, which trees to control, what methods to use, and the estimated cost. However, it is challenging to determine accurate costs due to the complexity of multiple site- and tree-related factors. In New Zealand, control costs are highly variable because understanding of costs per method are outdated and the complexities involved are not well elucidated. This paper explores why and how control costs vary to better predict costs in the future. To explore the factors that influence cost, we ran an online workshop that generally followed a nominal group process with several experienced project managers and contractors involved in invasive conifer control. To effectively estimate the cost of control, contractors and project managers must first understand how various site and tree-related factors influence the choice of control method. Contractors and project managers then determine how the factors influence cost. These results come at an important time in the management of invasive conifers in New Zealand and elsewhere. Control operations are increasing and expanding, requiring accurate estimates of costs to plan future operations. The findings will also be useful for training new staff and updating guidelines on invasive conifer control.
‘What matters to you?’ Health outcome prioritisation in treatment decision-making for older patients
Authors: Festen Suzanne , van Twisk Yvette Z , van Munster Barbara C , de Graeff Pauline
Published: July 2021

Background

for shared decision-making, it is important to discuss of the patients’ priorities in order to align treatment decisions with these priorities.

Objective

to assess the most important health outcome for older patients on the verge of making a treatment decision, using the Outcome Prioritization Tool (OPT). Secondary objectives were the feasibility of the OPT and patient variables associated with prioritising different health outcomes.

Design

retrospective cohort study.

Setting and subjects

at the University Medical Hospital Groningen, the Netherlands, 350 patients were included who visited the geriatric outpatient clinic during the work-up regarding a complex treatment decision (such as cancer treatment or heart valve replacement).

Methods

during geriatric assessment, patients prioritised between four health outcomes, using the OPT.

Results

median age was 78.5 years, 172 (49.1%) were referred regarding a treatment decision for a malignant disease. Cognitive impairment was present in 23.6%. Most patients (55.2%) prioritised maintaining independence as their most important goal, followed by extending life in 21.1%. Only cognitive impairment was significantly associated with prioritising extending life as the most important health outcome. For 107 patients (30.6%), the OPT was not feasible; these patients more often had malnutrition and assisted living.

Conclusions

the main health outcome of older patients on the verge of making a treatment decision was maintaining independence, followed by extending life. Patients with cognitive impairment more often prioritised extending life. The OPT was feasible as a decision aid for most patients. For optimal shared decision-making, it is crucial to take patient preferences into account.
Estimation of Airborne Vapor Concentrations of Oil Dispersants COREXIT™ EC9527A and EC9500A, Volatile Components Associated with the Deepwater Horizon Oil Spill Response and Clean-up Operations
Authors: Stenzel Mark R , Arnold Susan F , Ramachandran Gurumurthy , Kwok Richard K , Engel Lawrence S , Sandler Dale P , Stewart Patricia A
Published: July 2021

The Deepwater Horizon (DWH) drilling unit explosion above the Macondo oil well on 20 April 2010 caused the release of approximately 4.9 million barrels (779 million L) of oil into the Gulf of Mexico. As part of a larger spill response and clean-up effort, approximately 1.84 million gallons (6.81 million L) of chemical dispersants COREXIT™ EC9500A and COREXIT™ EC9527A were applied to the resultant oil slicks through spraying on the water surface by plane and by vessel and through injection at the release source near the seabed. The GuLF STUDY is investigating the health effects of workers involved in the oil spill response and clean-up after the DWH explosion, and estimates of possible exposure to chemical dispersants were needed. Exposures were estimated to the volatile components of COREXIT™ EC9500A [petroleum distillates, hydrotreated light, and propylene glycol (PG)] and of COREXIT™ EC9527A [2-butoxyethanol (2-BE) and PG] using two of AIHA IHMOD2.0© mathematical modeling tools along with the dispersants’ chemical and physical properties. Monte Carlo simulations were used to reflect uncertainty in input parameters with both the two-box, constant emission model and the near and mid field plume model for indoor and outdoor activities, respectively. Possible exposure scenarios considered various evaporation rates, sizes of the dispersant pool, wind speeds, and ventilation rates. For the two-box model, mean near field exposure estimates to 2-BE ranged from 0.9 to 5.7 ppm, while mean far field estimated exposures ranged from 0.3 to 3.5 ppm. Estimates of mean near field plume model exposures ranged from 0.01 to 3.7 ppm at 2.5 ft from the source, and <0.01 to 0.3 ppm at 10 ft from the source. Estimated exposures to PG were approximately 10% of the calculated 2-BE exposures and exposures to petroleum distillates about 40% higher than the 2-BE estimates. Results indicate that compared with current occupational exposure guidelines, overexposure to petroleum distillates and PG probably did not occur in our study, but under some conditions, for short periods, exposure to 2-BE may have exceeded the limits for peak exposures. These estimates were developed for use in job-exposure matrices to estimate exposures of workers having contact with dispersant vapors for the GuLF STUDY.
Exposure Assessment Techniques Applied to the Highly Censored Deepwater Horizon Gulf Oil Spill Personal Measurements
Authors: Stenzel Mark R , Groth Caroline P , Banerjee Sudipto , Ramachandran Gurumurthy , Kwok Richard K , Engel Lawrence S , Sandler Dale P , Stewart Patricia A
Published: July 2021

The GuLF Long-term Follow-up Study (GuLF STUDY) is investigating potential adverse health effects of workers involved in the Deepwater Horizon (DWH) oil spill response and cleanup (OSRC). Over 93% of the 160 000 personal air measurements taken on OSRC workers were below the limit of detection (LOD), as reported by the analytic labs. At this high level of censoring, our ability to develop exposure estimates was limited. The primary objective here was to reduce the number of measurements below the labs’ reported LODs to reflect the analytic methods’ true LODs, thereby facilitating the use of a relatively unbiased and precise Bayesian method to develop exposure estimates for study exposure groups (EGs). The estimates informed a job-exposure matrix to characterize exposure of study participants. A second objective was to develop descriptive statistics for relevant EGs that did not meet the Bayesian criteria of sample size ≥5 and censoring ≤80% to achieve the aforementioned level of bias and precision. One of the analytic labs recalculated the measurements using the analytic method’s LOD; the second lab provided raw analytical data, allowing us to recalculate the data values that fell between the originally reported LOD and the analytical method’s LOD. We developed rules for developing Bayesian estimates for EGs with >80% censoring. The remaining EGs were 100% censored. An order-based statistical method (OBSM) was developed to estimate exposures that considered the number of measurements, geometric standard deviation, and average LOD of the censored samples for N ≥ 20. For N < 20, substitution of ½ of the LOD was assigned. Recalculation of the measurements lowered overall censoring from 93.2 to 60.5% and of the THC measurements, from 83.1 to 11.2%. A total of 71% of the EGs met the ≤15% relative bias and <65% imprecision goal. Another 15% had censoring >80% but enough non-censored measurements to apply Bayesian methods. We used the OBSM for 3% of the estimates and the simple substitution method for 11%. The methods presented here substantially reduced the degree of censoring in the dataset and increased the number of EGs meeting our Bayesian method’s desired performance goal. The OBSM allowed for a systematic and consistent approach impacting only the lowest of the exposure estimates. This approach should be considered when dealing with highly censored datasets.
Tracing the evolution of aneuploid cancers by multiregional sequencing with CRUST
Authors: Chattopadhyay Subhayan , Karlsson Jenny , Valind Anders , Andersson Natalie , Gisselsson David
Published: July 2021

Clonal deconvolution of mutational landscapes is crucial to understand the evolutionary dynamics of cancer. Two limiting factors for clonal deconvolution that have remained unresolved are variation in purity and chromosomal copy number across different samples of the same tumor. We developed a semi-supervised algorithm that tracks variant calls through multi-sample spatiotemporal tumor data. While normalizing allele frequencies based on purity, it also adjusts for copy number changes at clonal deconvolution. Absent à priori copy number data, it renders in silico copy number estimations from bulk sequences. Using published and simulated tumor sequences, we reliably segregated clonal/subclonal variants even at a low sequencing depth (~50×). Given at least one pure tumor sample (>70% purity), we could normalize and deconvolve paired samples down to a purity of 40%. This renders a reliable clonal reconstruction well adapted to multi-regionally sampled solid tumors, which are often aneuploid and contaminated by non-cancer cells.
Distance-guided protein folding based on generalized descent direction
Authors: Wang Liujing , Liu Jun , Xia Yuhao , Xu Jiakang , Zhou Xiaogen , Zhang Guijun
Published: July 2021

Advances in the prediction of the inter-residue distance for a protein sequence have increased the accuracy to predict the correct folds of proteins with distance information. Here, we propose a distance-guided protein folding algorithm based on generalized descent direction, named GDDfold, which achieves effective structural perturbation and potential minimization in two stages. In the global stage, random-based direction is designed using evolutionary knowledge, which guides conformation population to cross potential barriers and explore conformational space rapidly in a large range. In the local stage, locally rugged potential landscape can be explored with the aid of conjugate-based direction integrated into a specific search strategy, which can improve the exploitation ability. GDDfold is tested on 347 proteins of a benchmark set, 24 template-free modeling (FM) approaches targets of CASP13 and 20 FM targets of CASP14. Results show that GDDfold correctly folds [template modeling (TM) score ≥ = 0.5] 316 out of 347 proteins, where 65 proteins have TM scores that are greater than 0.8, and significantly outperforms Rosetta-dist (distance-assisted fragment assembly method) and L-BFGSfold (distance geometry optimization method). On CASP FM targets, GDDfold is comparable with five state-of-the-art full-version methods, namely, Quark, RaptorX, Rosetta, MULTICOM and trRosetta in the CASP 13 and 14 server groups.
A critical appraisal of the circulating levels of differentially expressed microRNA in endometriosis
Authors: Leonova Anna , Turpin Victoria E , Agarwal Sanjay K , Leonardi Mathew , Foster Warren G
Published: July 2021

Endometriosis is a common gynecological condition characterized by estrogen dependence, chronic pelvic pain, infertility, and diagnostic delay of between 5.4 and 12 years. Despite extensive study, no biomarker, either alone or in combination with other markers, has proven superior to laparoscopy for the diagnosis of endometriosis. Recent studies report that circulating levels of differentially expressed microRNA (miRNA) in women with endometriosis compared with controls are potential diagnostic tools. However, the lack of replication and absence of validated differential expression in novel study populations have led some to question the diagnostic value of miRNA. To elucidate potential reasons for the lack of replication of study results and explore future directions to enhance replicability of circulating miRNA results, we carried out an electronic search of the miRNA literature published between 2000 and 2020. Eighteen studies were identified in which 63 different miRNAs were differentially expressed in the circulation of women with endometriosis compared with controls. However, the differential expressions of only 14 miRNAs were duplicated in one or more studies. While individual miRNAs lacked diagnostic value, miRNA panels yielded sensitivity and specificity equal to or better than laparoscopy in five studies. Important differences in study design, sample processing, and analytical methods were identified rendering direct comparisons across studies problematic and could account for the lack of reproducibility of study results. We conclude that while the results of miRNA studies to date are encouraging, refinements to study design and analytical methods should enhance the reliability of circulating miRNA for the diagnosis of endometriosis.
Identifying online risk markers of hard-to-observe crimes through semi-inductive triangulation: The case of human trafficking in the United States
Authors: de Vries Ieke , Radford Jason
Published: July 2021

Many types of crime are difficult to study because they are hard to operationalize, hidden from the public, or both. With communication increasingly moving to online domains, recent work has begun to examine whether the online domain contains traces of such hard-to-observe crimes. This study explores the online linguistic contours of hard-to-observe crimes through a rigorous mixed-methods approach that combines interviews and computational text analysis. Using human trafficking in illicit massage businesses as a proof-of-concept, we show how this approach, which we call semi-inductive triangulation, meets the empirical contextuality and relationality of crime traces in the online domain. The findings contribute to an emerging field of computational criminology and call for an integration of linguistic approaches in criminology.
Prediction Rules for Ruling Out Endocarditis in Patients With Staphylococcus aureus Bacteremia
Authors: van der Vaart Thomas W , Prins Jan M , Soetekouw Robin , van Twillert Gitte , Veenstra Jan , Herpers Bjorn L , Rozemeijer Wouter , Jansen Rogier R , Bonten Marc J M , van der Meer Jan T M
Published: July 2021

Background

Staphylococcus aureus bacteremia (SAB) is in 10% to 20% of cases complicated by infective endocarditis. Clinical prediction scores may select patients with SAB at highest risk for endocarditis, improving the diagnostic process of endocarditis. We compared the accuracy of the Prediction Of Staphylococcus aureus Infective endocarditiseTime to positivity, Iv drug use, Vascular phenomena, preExisting heart condition (POSITIVE), Predicting Risk of Endocarditis Using a Clinical Tool (PREDICT), and VIRSTA scores for classifying the likelihood of endocarditis in patients with SAB.

Methods

Between August 2017 and September 2019, we enrolled consecutive adult patients with SAB in a prospective cohort study in 7 hospitals in the Netherlands. Using the modified Duke Criteria for definite endocarditis as reference standard, sensitivity, specificity, negative predictive (NPV), and positive predictive values were determined for the POSITIVE, PREDICT, and VIRSTA scores. An NPV of at least 98% was considered safe for excluding endocarditis.

Results

Of 477 SAB patients enrolled, 33% had community-acquired SAB, 8% had a prosthetic valve, and 11% a cardiac implantable electronic device. Echocardiography was performed in 87% of patients, and 42% received transesophageal echocardiography (TEE). Eighty-seven (18.2%) had definite endocarditis. Sensitivity was 77.6% (65.8%–86.9%), 85.1% (75.8%–91.8%), and 98.9% (95.7%–100%) for the POSITIVE (n = 362), PREDICT, and VIRSTA scores, respectively. NPVs were 92.5% (87.9%–95.8%), 94.5% (90.7%–97.0%), and 99.3% (94.9%–100%). For the POSITIVE, PREDICT, and VIRSTA scores, 44.5%, 50.7%, and 70.9% of patients with SAB, respectively, were classified as at high risk for endocarditis.

Conclusions

Only the VIRSTA score had an NPV of at least 98%, but at the expense of a high number of patients classified as high risk and thus requiring TEE.

Clinical Trials Registration

Netherlands Trial Register code 6669.
Impact of nest sanitation behavior on hosts’ egg rejection: an empirical study and meta-analyses
Authors: Li Qihong , Bi Jianli , Wu Jiangwen , Yang Canchao
Published: July 2021

Egg rejection in birds is a specific adaptation toward avian brood parasitism, whereas nest sanitation is a general behavior for cleaning the nest and avoiding predation. However, both behaviors refer to the action of ejecting objects out of the nest, and nest sanitation has been proposed as a pre-adaptation for egg rejection. Here, we tested the eliciting effect of nest sanitation on egg rejection in the red-whiskered bulbul Pycnonotus jocosus, a potential host species that are sympatric with parasitic cuckoos. We conducted meta-analyses of previous studies on both nest sanitation and egg rejection, in order to evaluate the consistency of our conclusions. Our results showed that nest sanitation did not elicit egg rejection in P. jocosus. The conclusions concerning such an eliciting effect from previous studies were mixed, whereas the methodologies were inconsistent, making the studies unsuitable for comparisons. However, the ejection frequency of nest sanitation was consistently higher than the frequency of egg rejection across different host species or populations. These results suggest that nest sanitation, which is an ancient behavior, is more fundamental than egg rejection, but the effect of the former on the latter is complex and needs further study. Standardized methodologies and the integration of behavior, physiology, and modeling may provide better opportunities to explore the relationship between nest sanitation and egg rejection.
Safety, feasibility and prognostic value of stress perfusion CMR in patients with pacemaker
Authors: Pezel T , Lacotte J , Toupin S , Garot P , Hovasse T , Unterseeh T , Sanguineti F , Ait Said M , Salerno F , Fiorina L , Manenti V , Horvilleur J , Garot J
Published: July 2021

Funding Acknowledgements

Type of funding sources: None.

BACKGROUND

Several studies have shown the excellent prognostic value of stress cardiovascular magnetic resonance (CMR). However, its prognostic value in patients with pacemaker (PM) remains unknown because most studies excluded PM patients.

PURPOSE

This study aimed to assess the prognostic value of vasodilator stress perfusion CMR in patients with PM.

METHODS

Consecutive patients with MR-conditional pacemakers referred for stress perfusion CMR at 1.5 T were followed for the occurrence of major adverse cardiovascular events (MACE), defined by cardiovascular death or nonfatal myocardial infarction. Cox regressions analyses were performed to determine the prognostic value of CMR-parameters. The quality of CMR was rated by two observers blinded to clinical details. Data on pacemaker and leads were collected pre- and post-CMR.

RESULTS

Of 224 patients who completed the stress CMR protocol, 2 patients had inconclusive stress CMR due to artefact and 203 patients (72.9% male, mean age 71.4 ± 8.7 years) completed the follow-up (median [interquartile range], 7.0 [5.2-7.3] years). Among those, 23 experienced a MACE (11.3%). Stress CMR was well tolerated with no major adverse events. All scans were completed successfully with no significant change in lead thresholds or pacing parameters. Overall, the image quality was rated good or excellent in 84.1% of segments. Using Kaplan-Meier analysis, inducible ischemia and late gadolinium enhancement (LGE) were significantly associated with the occurrence of MACE (hazard ratio, HR: 11.80 [95% CI, 4.63-30.30]; and HR: 6.74 [95% CI, 2.47-18.40], both p < 0.001; respectively). In multivariable Cox regression, inducible ischemia and LGE were independent predictors of a higher incidence of MACE (HR: 5.24 [95% CI, 2.61-14.40]; and HR: 2.98 [95% CI, 2.25-4.02]; both p < 0.001; respectively). In patients with ischemia, CMR-related coronary revascularization showed no benefit in reducing MACE (p = 0.25).

CONCLUSION

Stress CMR is safe, feasible and has a good discriminative prognostic value in consecutive patients with PM.
Myocardial perfusion after COVID-19 infection: No persisting impaired myocardial blood flow in surviving patients
Authors: Thornton G , Shetye A , Knott K , Razvi Y , Vimalesvaran K , Kurdi H , Artico J , Yousef S , Antonakaki D , Kellman P , Knight D , Cole GD , Moon JC , Fontana M , Treibel TA
Published: July 2021

Funding Acknowledgements

Type of funding sources: None.

Background

 Acute myocardial damage is common in hospitalized patients with severe COVID-19, with evidence of myocardial infarction and myocarditis demonstrated on cardiovascular magnetic resonance (CMR). Post-mortem studies have also implicated microvascular thrombosis, which may cause persistent microvascular disease. 

Purpose

 To determine the long-term coronary sequelae in recovered COVID-19 using multiparametric CMR including state-of-the-art inline quantitative stress myocardial blood flow (sMBF) mapping to assess global and regional sMBF.

Methods

 Prospective, multicentre observational study of recovered COVID-19 patients scanned at three London CMR units. Results were compared to a propensity-matched, pre-COVID chest pain cohort (104 patients referred for perfusion CMR, with subsequently demonstrated unobstructed coronary arteries) and 27 healthy volunteers (HV). Perfusion image analysis was performed using a novel artificial intelligence approach deriving global and regional stress and rest MBF with a cut-off of >2.25mL/g/min signifying normal sMBF and <1.82mL/g/min abnormal sMBF (Kotecha JCVI 2019). 

Results

 104 recovered, post-COVID patients (median age 62 years, 76% male; 89[87%] hospitalised, 41/89[46%] requiring ICU) underwent adenosine-stress perfusion CMR at a median 131(IQR 43-179) days from COVID-19 diagnosis. Median LVEF was 67% (IQR 60-71%; 12 (11.5%) with impaired LVEF), 51 patients (49%) had late gadolinium enhancement (LGE); 18% infarct-pattern and 33% non-ischaemic LGE.  Global stress MBF in post-COVID patients was no different to age-, sex- and co-morbidities-matched controls (2.57 ± 0.77 vs. 2.40 ± 0.75 ml/g/min, p = 0.11, Figure 1), though lower than HV (3.00 ± 0.76 ml/g/min, p = 0.001). Post-COVID, multivariate predictors of low sMBF were male sex (OR 0.57, 95%CI 0.41-0.80, p = 0.001) and hypertension (OR 0.67, 95%CI 0.51-0.88, p = 0.004), but not COVID-19 disease severity (ICU admission) or presence of scar (ischemic/non-ischemic).  21/42 with reduced sMBF (<2.25mL/g/min) had regional perfusion defects consistent with epicardial coronary disease.

Conclusions

  COVID-19 survivors do not demonstrate evidence of reduced global MBF by CMR compared to risk factor matched controls. Stress perfusion CMR identifies etiology of acute myocardial damage (infarction/myocarditis) and presence of occult coronary ischemia.
Liver magnetic resonance relaxometry can provide useful markers for the assessment of right heart failure in dilated cardiomyopathy
Authors: Rafouli-Stergiou P , Symons R , Droogne W , Dresselaers T , Masci PG , Bogaert J
Published: July 2021

Funding Acknowledgements

Type of funding sources: None.

Introduction

In dilated cardiomyopathy (DCM) patients at risk of developing right heart failure (RHF), early depiction of congestive heart failure (CHF) is pivotal to inform about the hemodynamic status and tailor medical therapy.

Purpose

We hypothesized that increased liver relaxation times measured at routine cardiovascular magnetic resonance (CMR), reflecting passive hepatic congestion, may be a valuable imaging biomarker to depict CHF.

Methods

The study cohort included DCM patients with (n = 48) and without (n = 46) right ventricular dysfunction (RVD), defined as a right ventricular ejection fraction <35%, and >45%, respectively, and a control group (n = 40). Native T1, T2, and extracellular volume (ECV) liver values were measured on routinely acquired cardiac maps.

Results

DCM with RVD patients had higher C-reactive protein, troponin I and NT-pro BNP values, and worse LV functional parameters than DCM without RVD patients (all p < 0.001). T1, T2 and ECV liver values were significantly higher in DCM with, compared to DCM without, RVD patients and also compared to controls [T1: 675 ± 88ms vs. 538 ± 39ms and 540 ± 34ms; T2: 54 ± 8ms vs. 45 ± 5ms and 46 ± 4ms; ECV: 36 ± 7% vs. 29 ± 4% and 30 ± 3%, respectively (all p < 0.001)]. Gamma glutamyltranspeptidase (γGT) correlated moderately but significantly with liver native T1 (r2 =0.34), T2 (r2 =0.27), and ECV (r2 =0.23) (all p < 0.001). Using right atrial pressure (RAP > 5 mmHg), as a surrogate measure of RHF, liver native T1 yielded at ROC analysis the highest AUC (0.906), significantly higher than liver ECV (0.813), γGT (0.806), liver T2 (0.797), total bilirubin (0.737) and alkaline phosphatase (0.561) [Figure 1]. A liver native T1 value of 617 ms showed a sensitivity of 79.5% and a specificity of 91.0% in identifying RHF. Density plots to discriminate between presence and absence of RHF are demonstrated at Figure 2. Excellent intra-/inter-observer agreement was found for assessment of native T1/T2/ECV liver values.

Conclusion

In DCM patients, assessment of liver relaxation times acquired on a CMR exam, may provide valuable information with regard to the presence of RHF.
Outcomes of cardiovascular magnetic resonance imaging in people living with HIV
Authors: Arendt C , De Leuw P , Haberl A , Kann G , Wolf T , Stephan C , Schuettfort G , Arcari L , Vasquez M , Albrecht M , Escher F , Vogl T , Zeiher A , Nagel E , Puntmann V
Published: July 2021

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction

People living with human immunodeficiency virus (HIV, PLWH) are at increased risk of cardiovascular disease (CVD). HIV infection and accelerated traditional risk factors due to highly-active antiretroviral therapy (HAART) are proposed mechanisms for increased rate of heart failure (HF). The pathophysiological drivers of myocardial dysfunction and worse cardiovascular outcome in HIV remain poorly understood.

Purpose

To examine prognostic relationships of cardiac imaging measures with cardiovascular outcome in PLWH on HAART.

Methods

This is a prospective observational longitudinal study using cardiac magnetic resonance (CMR) imaging in consecutive PLHWH on long-term HAART who were screened for underlying CVD and followed up clinically for adjudicated adverse cardiovascular events (cardiovascular mortality, non-fatal acute coronary syndrome, an appropriate device discharge, or a documented HF hospitalization). Imaging protocol included routine assessment of cardiac volumes and function, scar by late gadolinium enhancement, myocardial perfusion and native T1 /T2 mapping. Time-to-event analysis was performed from the index CMR exam to the first single event per patient Systematic risk scores for CVD (Framingham risk score (FRS), Data Collection on Adverse effects of anti-HIV Drugs score, D:A:D and MAGGIC integer score) were calculated using original online calculators.

Results

156 participants (males 62%, 50 [42-57] years of age) were included. 24 events were observed (4 HF deaths, 1 sudden cardiac death, 2 non-fatal acute myocardial infarction, 1 appropriate device discharge and 16 HF hospitalizations) during a median follow-up of 13 [9-19] months. Patients with events had higher native T1 (ms, 1149 [1115-1163] ms vs. 1110 [1075-1138] ms), native T2 (ms, 40 [38-41] vs. 37 [36-39]), LV mass index (g/m², 65 [49-77] vs. 57 [49-64]) p < 0.05 for all). In multivariable analyses, native T1 was independently predictive of adverse events (ChiSq 15.9, p < 0.001, native T1 (10 ms) hazard ratio (95% confidence interval) 1.20 (1.08-1.33), p = 0.001), followed by a model that also included LV mass (ChiSq 17.1, p < 0.001). Traditional cardiovascular risk scores were not predictive of the adverse events.

Conclusions

Native myocardial T1 and LV mass by CMR, as opposed to traditional cardiovascular risk scores, predict cardiovascular outcome in PLWH, together reflecting the pathological myocardial remodeling of myocardial fibrosis and inflammation that potentially explain higher rates of HF in PLWH as compared to the non-infected population. These findings may inform personalized approaches to screening and early intervention to reduce the burden of HF.