bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental validation of depolarizing Mueller matrix model via ex vivo colon samples
Authors: Ivanov Deyan , Borisova Ekaterina , Novikova Tatiana , Ossikovski Razvigor
Published: April 2021

Experimental validation of a previously reported depolarizing Mueller matrix model is crucial to understanding the light-tissue interactions and the morphological alterations originating in malignant tissue zones in terms of their optical properties. This manuscript is a continuation of a previously reported case study, where a theoretical model was introduced with an additional Monte Carlo simulation. The main aim of this study is to empirically validate both theory and modelling. Once extracted from an experimental Mueller matrix via symmetric decomposition, the polarimetric quantities were compared with the corresponding parameters previously determined from polarized Monte Carlo simulations. Our results were obtained from an ex vivo colon sample and indicate a potential capability to provide supplementary polarimetric data to physicians and the gold standard histopathology analysis.
Spatial distribution of the electric field of laser pulses in optical fibers having a gradient profile of the refractive index. Linear case
Authors: Bozhikoliev I , Slavchev V , Dakova A , Dakova D , Kovachev K , Kovachev L
Published: April 2021

The aim of the present research is to investigate the spatiotemporal regime of propagation of three-dimensional optical pulses in fibers with spatial dependence of the refractive index. An exact analytical solution of the linearized equation is found. Numerical simulations are conducted of the solutions obtained.
A new basic structure suitable for a fully integrated all-fiber-optic stimulated emission dye source
Authors: Vladev V , Todorova M , Slavchev V , Brazkova M. , Belina E , Bozhkov S , Radusheva P
Published: April 2021

In the present work, our research is focused on an innovative compact all-fiber-optic structure suitable for the development of fully integrated dye lasers. The structure is based on a standard fiber-optic glass ferrule with two parallel openings along its length with diameters of 125 μm. A Fabry-Perot cavity is formed in one of the openings using two fused silica optical fibers with flat end facets. An angle-polished optical fiber with a reflective metal coating is placed in the second opening through which the active medium is pumped transversely. The active medium used is the Rhodamine 6G dye dissolved in glycerine, which is pumped by the 337.1-nm wavelength laser pulses of a nitrogen TEA laser. The ferrule-based design allows for a simplified set-up procedure and the integration of the pumping system to the basic structure of the laser, thus making it very compact. The design of the light source presented allows its future use in applications, such as lab-on-a-fiber, lab-on-a-chip and total analysis micro systems.
Study optical properties of the thin HfO2 coatings deposited by DC reactive magnetron sputtering
Authors: Rabadzhiyska S , Ormanova M , Valkov S , Ivanov N , Terziyska P , Ivanov K , Petrov P
Published: April 2021

Thin HfO2 films were deposited on polished microscope glass substrates by DC magnetron sputtering at bias voltages of -85 V, -100 V, -115 V, -130 V and -145 V. The deposited films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM) and UV-VIS-NIR spectrophotometry. The XRD results show the presence of a polycrystalline monoclinic phase. The roughness calculated from the AFM images increases as the bias voltage is raised to -130 V and then starts decreasing. The effect was also investigated of the bias voltage on the optical properties of the HfO2 films.
Research on oxygen saturation based on statistical analyses
Authors: Tang Rui , Zhang Lei , Zeng Jingjing , Wang Lu
Published: April 2021

We propose indicators to measure blood oxygen saturation: 1. Mean, which reflects the central tendency of blood oxygen saturation; 2. Standard deviation, which reflects the dispersion of SpO2; 3. Hurst exponent, which indicates whether the time series is continuous or anti-continuous. Participants with nearly the same physiological characteristics except age are selected from all participants, and they are divided into female and male groups for visual analysis. We speculate that the SpO2 series model had a certain relationship with age. Subsequently, the quantitative method is used to conduct a stepwise regression analysis by using age, BMI, gender and smoking. Finally, we find that the mean of SpO2 is related to age.
Application of Machine Learning in Recommendation System
Authors: Gao Shan
Published: April 2021

China’s science and technology has been basically maintained in a state of rapid development, among which machine learning has been widely used in many fields of society. For the economic and financial fields, if they want to make effective use of machine learning, the first thing to do is to comprehensively analyze the advantages and disadvantages of each algorithm, and then use machine learning to build the corresponding user recommendation system, so as to understand the actual adaptability of each algorithm. The following sections will analyze the application of machine learning in recommender systems.
Health Evaluation Method of Supercapacitor Based on Data Mining
Authors: Fang Ziwei , Liu Shuli , Zhao Yanming
Published: April 2021

With the wide application of super capacitor energy storage system as energy storage device on urban rail trains, the problem of its safe operation has attracted great attention. In order to ensure the reliability of the supercapacitor energy storage system, it is necessary to evaluate its health effectively. In view of the fact that the existing model-based supercapacitor evaluation methods are difficult to establish a reasonable and accurate model and the parameter estimation is complex, a data-driven supercapacitor health evaluation method is proposed. In this method, based on the data of voltage, current, temperature and external characteristic parameters of charge and discharge of supercapacitor, the weighted Euclidean distance formula is introduced, the mixed weighted Euclidean distance is calculated, and the comprehensive evaluation index of supercapacitor health state is obtained. It can quickly and effectively evaluate the health status of supercapacitors.
Research on Data Center Load Balancing Technology Based on SDN
Authors: Cheng Cheng
Published: April 2021

With the rise of mobile Internet and big data, the continuous expansion of data center network deployment, the trend toward more complex traffic patterns and fine-grained performance management requirements, have brought more and more network performance issues to the fore. As an emerging network architecture, SDN separates the control plane from the data plane, and has the characteristics of centralized control and programmable. The centralized control feature of SDN technology enables the SDN controller to dynamically obtain network topology, link information, node information, and flow information in a timely manner, thereby realizing flexible and fine-grained centralized scheduling of network flows, which is very suitable for the needs of data centers. Due to the high dynamic nature of SDN, how to improve the timeliness of its load balancing and better solve network congestion is very important. Aiming at the problems in data center network applications, this paper studies the SDN-based data center network load balancing management system structure, and discusses the load balancing technology of data center server clusters based on improved ant colony algorithm.
A Regional Network Topology Construction Algorithm Based On Sampling Measurement
Authors: Tao Zhiyuan , Liu Yan
Published: April 2021

Network topology construction is one of the basic means to study the target network. Whether it is the discovery of vital nodes, IP location or network characteristics mining, a complete and accurate network topology is needed. In this paper, a regional network topology construction algorithm based on sampling measurement is proposed to solve the problem of high time cost and resource waste of existing algorithms. Firstly, multiple vantage points located inside and outside the target area are selected to form a probing set. Then the IPes of the target area is extracted based on sampling to form the target IP set. Finally, the probing set is used to probe the target IP set periodically. The network topology of the target region was constructed based on the results of a 40-day internet measurement and compared with the existing database. The experimental results show that the coverage rate of routing nodes in the target area is improved by more than 90% compared with the measured data provided by CAIDA (Center for Applied Internet Data Analysis) and by more than 10% compared with the measured data provided by IPIP.
A Retrieval Method for Chinese EMR Based on Semantic Knowledge Map
Authors: Li Hao , Zhang Runtong
Published: April 2021

Due to the diversity of natural language in Chinese electronic medical records, it is usually hard for traditional retrieval methods to provide ideal results. On this condition, this paper proposes a retrieval method for Chinese EMR based on semantic knowledge map. Through natural language processing and semantic analysis, we can build connections for medical knowledge, and organize all the entities into a visual knowledge map. After that, a novel retrieval method based on semantic knowledge map is proposed, which focuses on node connection of documents and terms. Through semantic extension and intention spread, the improved retrieval results are returned, and the results are reordered by correlation. Compared with general methods, this method can significantly improve the accuracy of Chinese EMR text retrieval and optimize the ranking strategy of retrieval results.
Prediction of special OD passenger flow based on transfer learning
Authors: Wang Yu , Zhang Zhengpu , Wang Xiaodong , Tao Cheng
Published: April 2021

The prediction of railway passenger flow has always been an important topic in the field of railway operation. Due to the limitation of the number of allocated tickets, some special OD(Origin to Destination) data are sometimes inaccurate. It will obviously affect the final prediction accuracy if it is directly used as a sample. However, it is very difficult to restore the biased data to the true value. In this paper, we choose case-based transfer learning to remove the unqualified samples from the target domain and replace them with the corresponding samples in the source domain and form the final training sample data set. At the same time, we choose the improved AdaBoost algorithm, the sample weight is adjusted by the error size, and the model is retrained to get the final model. The results show that the prediction accuracy of transfer learning based on improved AdaBoost algorithm is better than that of traditional ensemble learning, ARIMA model and multiple regression model. It also provides a new theoretical view for special OD passenger flow prediction in the future.
Research on Recognition Technology of Amur Tiger Gait Features Based on Video
Authors: Lili Zhou , Jinyu Wang , Tongjun Liu
Published: April 2021

With the continuous advancement of technology, people are paying more and more attention to the living environment of wild animals. Located at the top of the food chain of the forest ecosystem, the Siberian tiger is a flagship species and umbrella species for biodiversity protection. The effective protection and sustainable survival of its population has far-reaching natural and social significance for China’s ecological security1. At present, the research on the Siberian tiger is mainly concentrated in the biological fields such as genes and heredity. Only a small amount of research on the detection of Siberian tigers and their footprints in static images. Research on the behavior recognition of Siberian tigers in videos is currently in its infancy. In the field of computer vision, as an independent research object, more and more researchers pay attention to the automatic recognition of gait. Based on the human gait model, a standard database for evaluating the performance of gait recognition algorithms has been established to promote the research of gait recognition. development of. This article will use deep neural convolutional networks and feature subspace learning algorithms to extract the gait features of the Siberian tiger from video images and establish a gait model of the Siberian tiger. This will lay the foundation for the identification of Siberian tigers and further research on their health status, and provide a foundation for the wild Provide theoretical support for animal protection.
Time-series prediction model of PM2.5 concentration based on LSTM neural network
Authors: Li Yiyang
Published: April 2021

LSTM (long-short term memory neural network) is a neural network suitable for simulating and predicting time series changes. This paper designs a PM2.5 concentration prediction model based on the LSTM neural network. Use Python language programming implementation under the Tensor Flow framework, training the model using real weather data from 2015-01-01∼2019-01-01, and the obtained model can accurately predict the concentration change of future PM2.5. RMSE and DC were used as evaluation indexes to compare the LSTM neural network model with the traditional BP (Back Propagation) algorithm model. It turns out, LSTM model has the characteristics of high precision and stable prediction effect, proved that the time series prediction ability of the LSTM model is more superior. As an effective method for predicting PM2.5 concentration data, it can provide the basis for predicting pollutants.
Application of active learning algorithm in handwriting recognition numbers
Authors: Pu Tiantian
Published: April 2021

Active learning is very suitable for many problems in natural language processing, where unlabeled data may be abundant, but annotation is slow and expensive. This article aims to illustrate some active learning methods for handwritten digit recognition tasks, such as the least confidence and entropy methods. We investigated the previously used sequence model query selection strategies and used some selection strategies for sample labeling in handwritten digit recognition. We also conduct a large-scale empirical comparison of using multiple corpora, which shows that our proposed method improves the technical level.
Research on the method of warship formation threat assessment based on structural contribution degree
Authors: Song Guibao , Liu Zhenyu , Liu Tie , Qiang Yugong
Published: April 2021

In this paper, a threat assessment method based on the structural contribution of equipment is proposed. The complex network theory, entropy weight method, grey correlation method and other assessment models are comprehensively used to deconstruct the structural contribution of equipment to combat tasks from the perspective of the contribution of each ship to the structure of the entire formation. The research results can help to determine the benefit value and priority of each ship attacking the enemy formation, guide our commanders and soldiers to destroy the air defense system of the enemy formation so as to reduce the function of the system, and provide reference for the target allocation of attacking the enemy formation.
Queue scheduling mechanism of integrative intelligent network based on information age
Authors: Zheng Jiangshan , Yang Li , Pan Chengsheng , Shi Huaifeng
Published: April 2021

Aiming at the problems of deterministic transmission of delay-sensitive service flows and mixed transmission of different service flows in the integrative intelligent network, which can easily lead to network congestion collapse and excessive delay, a scheduling mechanism named SATAS based on information age is proposed. The service flows in the intelligent network aggregation node are classified into delay-sensitive and other types of service flows. Based on the idea of time division multiplexing, the service flow in the buffer queue is scheduled according to the gated list. Further, combined with the age of information, based on the multi-objective optimization decision-making theory, and according to the actual requirements of scheduling in the intelligent network, a suitable gate control list is obtained, thereby realizing the scheduling of business flows in the intelligent network. Finally, a simulation verification system is built to schedule different types of business flows. The simulation results show that the SATAS mechanism ensures the deterministic transmission of delay-sensitive service flows, while ensuring the mixed transmission of different service flows, reducing the queuing delay and frame loss rate.
Research on the formation logic and basic model of standards
Authors: Han Peng-Wu , Deng Xiao-Mei , Dang Wei , Nan Yi
Published: April 2021

The out-of-date and cross repetition of standards is one of the key issues in the current standardization work. Before the comprehensive application of modern technology to solve such issue, it is necessary to study the mechanism and logical relationship of standards in theory, so as to provide theoretical support for the research of modern technology. From the perspective of natural evolution and human social development, this paper studies and proposes the classification of standards and the mechanism of standards generation. Besides, from the perspective of system theory, the basic model of standards is also proposed and studied. Finally, from the per-spective of development and implementation, current issues are summarized, which provides support for the future study to propose a systematic scheme of standards out-of-date and cross repetition.
Development and Design of Crowd Evacuation Simulation System in Complex Environment
Authors: Zhou Runjia , Wang Weian , Xue Huijie , Chen Xudong , Wang Ziyang
Published: April 2021

In order to better evacuate people in emergencies and ensure the safety of people’s lives and properties, we designed and developed a simulation system for crowd evacuation in complex environments based on the RVO algorithm. The system has completed the functions of scene construction, crowd simulation, optimal path planning, evacuation process simulation and playback, and heat map analysis. After the evacuation process is over, the evacuation drawings, evacuation process and related content can be saved in the form of the entire project if the creator chooses to save it, which is convenient for future review.
Research on architecture design of UAV PHM system
Authors: Gao Tong
Published: April 2021

According to the application requirements of state prediction and health management (PHM) technology in the field of UAV, this paper analyzes the functional requirements of UAV PHM system by referring to the research results and application experience of PHM technology at home and abroad and combining with the current situation of UAV support in China. Furthermore, this paper designs the architecture of UAV PHM system and introduces the workflow of the system in detail, which provides guidance and reference for the improvement of UAV comprehensive support level.
HTFP2D: An efficient transform framework for power primary drawing
Authors: Hongbo Liang , zhanfeng Wang , Xiaoting Chen
Published: April 2021

Power system needs not only graphics files, but also model files to realize mapping and association between power equipment and drawings. Drawing files are often composed of hundreds of graphic elements, which need to be transformed into structured model files through identification. In this paper, a hybrid transformation framework of primary power drawing (htfp2d) is proposed. The method of text and graphics recognition is integrated. Through the identification of key elements, the model file of a drawing is constructed and the drawing is redrawn. Experiments show that the method can effectively identify various drawings and promote the inheritance and use of historical drawing resources.
Research on Coordinated Control of Dual Motors Based on DSP
Authors: Wu Lanjiang
Published: April 2021

In order to save energy and reduce emissions, improve the ecological environment and achieve sustainable development, the research and development of electric vehicles has become a common consensus in all countries in the world. As the core component of electric vehicles, the requirements for drive motors are getting higher and higher. The control strategy of the dual-stator motor is based on the mature vector control method of the traditional PMSM. The two sets of three-phase windings are transformed at the same time by rotating coordinate, and the vector control under the dual synchronous rotating coordinate is realized through separate decoupling; the control system uses TMS320F28335 as the control core, equipped with The dual stator motor vector control system makes full use of chip resources to realize the functions of rotor position detection, two-winding current and voltage acquisition and IGBT drive at the same time to complete the torque control of the two stator windings. It is verified by experiments that the control system meets the requirements of electric vehicle power system, with simple structure and strong practicability.
Shortest path planning for mobile chargers
Authors: Yi Huiyang , Shen Xiaojian , Wang Jiaqi
Published: April 2021

This paper studies the shortest path that a mobile charger should travel when charging a wireless rechargeable sensor network. Under the condition that the latitude and longitude of each node in the wireless rechargeable sensor network are known, we combine the actual working conditions of the mobile charger to establish a TSP problem model and use two improved modern optimization algorithms and three common optimization algorithms to solve. By comparing the results, we conclude that the improved genetic algorithm can obtain the shortest path length of 11485 m with the least number of iterations. The improved genetic algorithm has better applicability to the problem in this background.
A novel underwater bipedal walking soft robot bio-inspired by the coconut octopus
Authors: Wu Qiuxuan , Yang Xiaochen , Wu Yan , Zhou Zhijun , Wang Jian , Zhang Botao , Luo Yanbin , Chepinskiy Sergey A , Zhilenkov Anton A
Published: April 2021

In order to increase the compatibility between underwater robots and the underwater environment and inspired by the coconut octopus’s underwater bipedal walking, a method was proposed for bipedal walking for an underwater soft robot based on a spring-loaded inverted pendulum (SLIP) model. Using the characteristics of octopus tentacles rolling on the ground, a wrist arm was designed using the cable-driven method, and an underwater SLIP bipedal walking model was established, which makes an underwater soft robot more suitable for moving on uneven ground. An underwater bipedal walking soft robot based on coconut octopus was then designed, and a machine vision algorithm was used to extract the motion information for analysis. Experimental analysis shows that the underwater bipedal walking robot can achieve an average speed of 6.48 cm s−1, and the maximum instantaneous speed can reach 8.14 cm s−1.
A staggered 3-layer DOI PET detector using BaSO4 reflector for enhanced crystal identification and inter-crystal scattering event discrimination capability
Authors: Kang Han Gyu , Nishikido Fumihiko , Yamaya Taiga
Published: April 2021

The spatial resolution of small animal positron emission tomography (PET) scanners can be improved by the use of crystals with fine pitch and rejection of inter-crystal scattering (ICS) events, which leads to a better quantification of radiopharmaceuticals. On the other hand, depth-of-interaction (DOI) information is essential to preserve the spatial resolution at the PET field-of-view (FOV) periphery while keeping the sensitivity. In this study we proposed a novel staggered 3-layer DOI detector using BaSO4 reflector material for an enhanced crystal identification performance as well as ICS event rejection capability over those of ESR reflector based DOI detectors. The proposed staggered 3-layer DOI detector had 3-layer staggered LYSO crystal arrays (crystal pitch = 1 mm), an acrylic light guide, and a 4 × 4 SiPM array. The 16 SiPM anode signals were read out by using a resistive network to encode the crystal position and energy information while the timing signal was extracted from the common cathode. The crystal map quality was substantially enhanced by using the BaSO4 reflector material as compared to that of the ESR reflector due to the low optical crosstalk between the LYSO crystals. The ICS events can be rejected with BaSO4 by using simple pulse height discrimination thanks to the light collection efficiency difference that depends on the crystal layers. As a result, the total number of events was decreased around 26% with BaSO4 as compared to that of ESR. The overall energy resolution and coincidence timing resolution with BaSO4 were 19.7 ± 5.6% and 591 ± 160 ps, respectively which were significantly worse than 10.9 ± 2.2% and 308 ± 23 ps values of ESR because of the relatively low light collection efficiency with BaSO4 (1057 ± 308 ADC) compared to that of ESR (1808 ± 118 ADC). In conclusion, we found the proposed staggered 3-layer DOI detector using the BaSO4 reflector material with ICS event rejection capability can be a cost-effective solution for realizing high resolution and highly sensitive small animal PET scanners while minimizing the complexity of the SiPM readout circuit.
Ambipolar carbon nanotube transistors with hybrid nanodielectric for low-voltage CMOS-like electronics
Authors: Portilla Luis , Zhao Jianwen , Zhao Jing , Occhipinti Luigi G , Pecunia Vincenzo
Published: April 2021

The proliferation of place-and-forget devices driven by the exponentially-growing Internet of Things industry has created a demand for low-voltage thin-film transistor (TFT) electronics based on solution-processible semiconductors. Amongst solution-processible technologies, TFTs based on semiconducting single-walled carbon nanotubes (sc-SWCNTs) are a promising candidate owing to their comparatively high current driving capability in their above-threshold region at low voltages, which is desirable for applications with constraints on supply voltage and switching speed. Low-voltage above-threshold operation in sc-SWCNTs is customarily achieved by using high-capacitance-density gate dielectrics such as metal-oxides fabricated via atomic layer deposition (ALD) and ion-gels. These are unattractive, as ALD requires complex-processing or exotic precursors, while ion-gels lead to slower devices with poor stability. This work demonstrates the fabrication of low-voltage above-threshold sc-SWCNTs TFTs based on a high-capacitance-density hybrid nanodielectric, which is composed of a readily-made AlO
x
nanolayer and a solution-processed self-assembled monolayer (SAM). The resultant TFTs can withstand a gate-channel voltage of 1–2 V, which ensures their above-threshold operation with balanced ambipolar behavior and electron/hole mobilities of 7 cm2 V−1 s−1. Key to achieving balanced ambipolarity is the mitigation of environmental factors via the encapsulation of the devices with an optimized spin-on polymer coating, which preserves the inherent properties of the sc-SWCNTs. Such balanced ambipolarity enables the direct implementation of CMOS-like circuit configurations without the use of additional dopants, semiconductors or source/drain electrode metals. The resultant CMOS-like inverters operate in the above-threshold region with supply voltages in the 1–2 V range, and have positive noise margins, gain values surpassing 80 V/V, and a bandwidth exceeding 100 kHz. This reinforces SAM-based nanodielectrics as an attractive route to easy-to-fabricate sc-SWCNT TFTs that can operate in the above-threshold region and that can meet the demand for low-voltage TFT electronics requiring moderate speeds and higher driving currents for wearables and sensing applications.
Optimum design of an eight pole electromagnetic bearing
Authors: Bisht Shishir , Gupta Nitin Kumar , Tharke G D , Somani Nalin
Published: April 2021

The paper aims to give the step by step design procedure of an electromagnetic bearing having eight pole for machine tool applications having the shaft diameter of 20 mm and rotate with the speed of 750 rpm. The mathematical procedure consists of the geometrical as well as constraints due to losses occur in the electromagnetic bearing which makes the designing more accurate. Finally, optimization has been done to get the optimum values of the dimension of the electromagnetic bearing. By interior trust method numerical optimization has carried out to find out the optimum values of the dimensions of an electromagnetic bearing to maximize the electromagnetic force exerted by it. This has supported by a CAD model using Solid Works showing the dimensions of the model. The mathematical model compared with the available literature on electromagnetics bearing and found to be an effective with consideration of all iron and copper losses. The results show the designed bearing can produce a magnetic force of 166 N from each electromagnet on the shaft. For the application an electric hand drill machine has to be taken and an electromagnetic bearing consists of 8 electromagnets has been designed which is capable of generating 29 N of electromagnetic force onto the shaft of the electric hand drill machine.
Piezoelectric inchworm actuator using silicon as the mechanical material
Authors: Hughes George , Adams Mark
Published: April 2021

Piezoelectric inchworm actuators allow for a large stroke and high precision. This paper aims to minimize the footprint of the actuator by using semiconductor and MEMS fabrication techniques to build the frame and channel out of silicon wafers. The high precision of the semiconductor processes allows for precise tolerances as well as the ability to use batch processing for a shorter fabrication time. Using silicon as the mechanical material can also allow for the incorporation of the electrical signals into the frame.
The Torelli map restricted to the hyperelliptic locus
Authors: Landesman Aaron
Published: April 2021

Let

g
≥
2

g \geq 2

and let the Torelli map denote the map sending a genus

g
g

curve to its principally polarized Jacobian. We show that the restriction of the Torelli map to the hyperelliptic locus is an immersion in characteristic not

2
2

. In characteristic

2
2

, we show the Torelli map restricted to the hyperelliptic locus fails to be an immersion because it is generically inseparable; moreover, the induced map on tangent spaces has kernel of dimension

g
−
2

g-2

at every point.
Comparison of 2 Case Definitions for Ascertaining the Prevalence of Autism Spectrum Disorder Among 8-Year-Old Children
Authors: Maenner Matthew J , Graves Sierra J , Peacock Georgina , Honein Margaret A , Boyle Coleen A , Dietz Patricia M
Published: April 2021

The Autism and Developmental Disabilities Monitoring (ADDM) Network conducts population-based surveillance of autism spectrum disorder (ASD) among 8-year-old children in multiple US communities. From 2000 to 2016, investigators at ADDM Network sites classified ASD from collected text descriptions of behaviors from medical and educational evaluations which were reviewed and coded by ADDM Network clinicians. It took at least 4 years to publish data from a given surveillance year. In 2018, we developed an alternative case definition utilizing ASD diagnoses or classifications made by community professionals. Using data from surveillance years 2014 and 2016, we compared the new and previous ASD case definitions. Compared with the prevalence based on the previous case definition, the prevalence based on the new case definition was similar for 2014 and slightly lower for 2016. Sex and race/ethnicity prevalence ratios were nearly unchanged. Compared with the previous case definition, the new case definition’s sensitivity was 86% and its positive predictive value was 89%. The new case definition does not require clinical review and collects about half as much data, yielding more timely reporting. It also more directly measures community identification of ASD, thus allowing for more valid comparisons among communities, and reduces resource requirements while retaining measurement properties similar to those of the previous definition.
Associations between preoperative anaemia and hospital costs following major abdominal surgery: cohort study
Authors: Meyerov J , Louis M , Lee D K , Fletcher L , Banyasz D , Miles L F , Ma R , Tosif S , Koshy A N , Story D A , Bellomo R , Weinberg L
Published: April 2021

Background

Determining the cost-effectiveness and sustainability of patient blood management programmes relies on quantifying the economic burden of preoperative anaemia. This retrospective cohort study aimed to evaluate the hospital costs attributable to preoperative anaemia in patients undergoing major abdominal surgery.

Methods

Patients who underwent major abdominal surgery between 2010 and 2018 were included. The association between preoperative patient haemoglobin (Hb) concentration and hospital costs was evaluated by curve estimation based on the least-square method. The in-hospital cost of index admission was calculated using an activity-based costing methodology. Multivariable regression analysis and propensity score matching were used to estimate the effects of Hb concentration on variables related directly to hospital costs.

Results

A total of 1286 patients were included. The median overall cost was US $18 476 (i.q.r.13 784–27 880), and 568 patients (44.2 per cent) had a Hb level below 13.0 g/dl. Patients with a preoperative Hb level below 9.0 g/dl had total hospital costs that were 50.6 (95 per cent c.i. 14.1 to 98.9) per cent higher than those for patients with a preoperative Hb level of 9.0–13.0 g/dl (P < 0.001), 72.5 (30.6 to 128.0) per cent higher than costs for patients with a Hb concentration of 13.1–15.0 g/dl (P < 0.001), and 62.4 (21.8 to 116.7) per cent higher than those for patients with a Hb level greater than 15.0 g/dl (P < 0.001). Multivariable general linear modelling showed that packed red blood cell (PRBC) transfusions were a principal cost driver in patients with a Hb concentration below 9.0 g/dl.

Conclusion

Patients with the lowest Hb concentration incurred the highest hospital costs, which were strongly associated with increased PRBC transfusions. Costs and possible complications may be decreased by treating preoperative anaemia, particularly more severe anaemia.
Adaptation to the dietary sugar D-tagatose via genome instability in polyploid Candida albicans cells
Authors: Thomson Gregory J , Kakade Pallavi , Hirakawa Matthew P , Ene Iuliana V , Bennett Richard J
Published: April 2021

The opportunistic fungal pathogen Candida albicans undergoes an unusual parasexual cycle wherein diploid cells mate to form tetraploid cells that can generate genetically diverse progeny via a nonmeiotic program of chromosome loss. The genetic diversity afforded by parasex impacts clinically relevant features including drug resistance and virulence, and yet the factors influencing genome instability in C. albicans are not well defined. To understand how environmental cues impact genome instability, we monitored ploidy change following tetraploid cell growth in a panel of different carbon sources. We found that growth in one carbon source, D-tagatose, led to high levels of genomic instability and chromosome loss in tetraploid cells. This sugar is a stereoisomer of L-sorbose which was previously shown to promote karyotypic changes in C. albicans. However, while expression of the SOU1 gene enabled utilization of L-sorbose, overexpression of this gene did not promote growth in D-tagatose, indicating differences in assimilation of the two sugars. In addition, genome sequencing of multiple progenies recovered from D-tagatose cultures revealed increased relative copy numbers of chromosome 4, suggestive of chromosome-level regulation of D-tagatose metabolism. Together, these studies identify a novel environmental cue that induces genome instability in C. albicans, and further implicate chromosomal changes in supporting metabolic adaptation in this species.
SELECTION FOR RECOMBINATION IN PARTIALLY SELF-FERTILIZING POPULATIONS
Authors: Charlesworth D , Charlesworth B , Strobeck C
Published: April 2021

This paper confirms HOLDEN'S (1979) suggestion that certain types of fitness interactions between a pair of loci in partially self-fertilizing populations may promote selection for increased recombination between them. Our results are based on both algebraic and computer calculations of the fate of alleles at a third locus, which control the level of recombination between the selected pair. We also show that the behavior of the population mean fitness as a function of recombination fraction is not necessarily an indicator of the direction of selection on recombination in partially selfiig populations.
THE REGULATION OF WHITE LOCUS EXPRESSION: A DOMINANT MUTANT ALLELE AT THE WHITE LOCUS OF DROSOPHILA MELANOGASTER
Authors: Bingham Paul M
Published: April 2021

A new mutant allele (wDZL)at the white locus of Drosophila melanogaster is dominant to the wild-type allele, but apparently only when the two alleles are synapsed. When chromosomal rearrangements prevent somatic pairing between the two white alleles, wDZL is rendered recessive to wild type. This observation suggests that the dominance of wDZL is sensitive to a synapsis (transvection) effect. On the basis of this and other properties, it is proposed that wDZL causes the repression of transcription of a synapsed w+ allele, but not of a w+ allele elsewhere in the same nucleus. One model to account for this supposes that wDzL produces a repressor of white-locus transcription. This repressor is presumed to be so unstable that other white genes, removed from wDZL but in the same nucleus, are not detectably repressed. These properties may be simply understood if it is assumed that the repressor produced by the wDZL allele is an RNA molecule.
GENETIC EVIDENCE FOR A SILENT SUC GENE IN YEAST
Authors: Carlson Marian , Osmond Barbara C , Botstein David
Published: April 2021

The SUC genes (SUC1-SUC7) of Saccharomyces are a family of genes that are dispersed in the yeast genome. A SUC  + allele at any locus confers the ability to produce the enzyme invertase and, thus, to ferment sucrose. Most yeast strains do not carry SUC  + alleles at all possible SUC loci. We have investigated the naturally occurring negative (suc0) alleles present at SUC loci with the aim of distinguishing between two possible models for the structure of suc0 alleles: (1) suc0 alleles correspond to a simple absence of SUC genetic information; (2) suc0 alleles are "silent" SUC genes that either produce a defective product or are not expressed. To facilitate these studies, sucrose-nonfermenting strains were constructed that are congenic to S. cerevisiae strain S288C (SUC2  +), but carry at the SUC2 locus the naturally occurring negative allele, suc20, of strain FL100 (Lacroute 1968). These strains were used to study the genetic properties of the suc20 allele of FL100 and the suc0 alleles (suc10, suc30, etc.) of S288C. The suc20 allele was shown to revert to an active Suc+ state and to provide functional information at three points in the SUC2 gene in recombination experiments; this suc20 gene thus appears to be a "silent" gene. Similar tests for silent SUC genes in S288C (corresponding to loci other than SUC2) failed to reveal any additional silent genes.
Nationwide audit and feedback on implementation of antibiotic stewardship programmes in Norwegian hospitals
Authors: Skodvin Brita , Høgli June U , Gravningen Kirsten , Neteland Marion I , Harthug Stig , Akselsen Per E
Published: April 2021

Background

Implementation of antibiotic stewardship programmes (ASPs) in hospitals is challenging and there is a knowledge gap on how to pursue this process efficiently.

Objectives

To evaluate whether audit and feedback (A&F) is a feasible and useful methodology to assess and support the implementation of ASPs in hospitals.

Methods

A multidisciplinary team performed document reviews and on-site interviews with professionals involved in the implementation of ASPs. Oral feedback on preliminary findings and areas of improvement were provided on-site, followed by feedback reports summarizing major findings and recommendations. Descriptive statistics were used to present number of hospital trusts, interviewees, professions, disciplines, workload and costs.

Results

All 22 hospital trusts in Norway participated in the A&F conducted October 2017 to April 2019. Altogether, 446 leaders and healthcare workers were interviewed: 110 leaders, 336 health professionals of whom 89 were antimicrobial stewardship team members. Median number of days from audits were performed till reporting were 36 (IQR 30–49). Median workload for auditors per visit was 7 days (6–8). Total costs were €133 952. Main audit findings were that ASP structures were established in most hospital trusts, but leadership commitment and implementation of interventions were often lacking. The hospital trusts received feedback on establishing governance structures, setting local targets, implementing interventions and increased involvement of nurses.

Conclusions

Nationwide A&F provides a unique and comprehensive insight into the implementation of ASPs in hospitals and is feasible with a reasonable amount of resources. This approach can identify targets for improved implementation of ASPs in hospitals.
Volvulus of the transverse colon in an octogenarian veteran
Authors: Pickett Maryanne L , Mottershaw Ann M , Gupta Pramod , Huerta Sergio
Published: April 2021

In the USA, the third leading cause of a large bowel obstruction in adults is volvulus with torsion occurring commonly in the sigmoid and the cecum. Transverse colonic volvulus is exceedingly rare and specific involvement of the splenic flexure is even more uncommon. In the present report, we discuss a Veteran octogenarian who presented with a long-standing history of constipation, but then developed an acute abdomen from a large bowel obstruction. At laparotomy, he had a double closed loop obstruction with volvulus of the splenic flexure. The colon at the splenic flexure was ischemic with patchy areas of necrosis, but no perforation. He underwent a subtotal colectomy with an ileostomy. This case illustrates the need for prompt intervention of this unusual entity. Current trends in the incidence, management, morbidity and mortality are discussed.
Primary posterior mediastinal angiolipoma: a case report
Authors: Nakamura Daisuke , Kobayashi Nobutaka , Miyazawa Masahisa , Satomi Hidetoshi , Ihara Nobumaro , Tsunoda Mayu
Published: April 2021

An angiolipoma is a benign tumor, and a primary mediastinal angiolipoma is extremely rare. Herein, we describe the presentation and management of a posterior mediastinal angiolipoma in a woman with loss of consciousness. Chest computed tomography (CT) revealed a contrast-enhancing mass in the right posterior mediastinum, with intercostal arterial blood supply identified on three-dimensional reconstruction CT (3D-CT). Magnetic resonance imaging revealed a fatty component. Pre-operative embolization of the supplying intercostal artery was performed to reduce intraoperative bleeding. Mass resection was performed using video-assisted thoracic surgery. Histopathology confirmed angiolipoma diagnosis. Although rare, a posterior mediastinum angiolipoma should be considered a possibility; 3D-CT and pre-operative embolization may be useful in the surgical treatment of hypervascular mediastinal tumors, such as angiolipomas.
Urban green spaces in Dhaka, Bangladesh, harbour nearly half the country’s butterfly diversity
Authors: Chowdhury Shawan , Shahriar Shihab A , Böhm Monika , Jain Anuj , Aich Upama , Zalucki Myron P , Hesselberg Thomas , Morelli Federico , Benedetti Yanina , Persson Anna S , Roy Deponkor K , Rahman Saima , Ahmed Sultan , Fuller Richard A
Published: April 2021

Cities currently harbour more than half of the world’s human population and continued urban expansion replaces natural landscapes and increases habitat fragmentation. The impacts of urbanisation on biodiversity have been extensively studied in some parts of the world, but there is limited information from South Asia, despite the rapid expansion of cities in the region. Here, we present the results of monthly surveys of butterflies in three urban parks in Dhaka city, Bangladesh, over a 3-year period (January 2014 to December 2016). We recorded 45% (137 of the 305 species) of the country’s butterfly richness, and 40% of the species detected are listed as nationally threatened. However, butterfly species richness declined rapidly in the three study areas over the 3-year period, and the decline appeared to be more severe among threatened species. We developed linear mixed effect models to assess the relationship between climatic variables and butterfly species richness. Overall, species richness was positively associated with maximum temperature and negatively with mean relative humidity and saturation deficit. Our results demonstrate the importance of urban green spaces for nationally threatened butterflies. With rapidly declining urban green spaces in Dhaka and other South Asian cities, we are likely to lose refuges for threatened fauna. There is an urgent need to understand urban biodiversity dynamics in the region, and for proactive management of urban green spaces to protect butterflies in South Asia.
Prolonged Sars-CoV-2 Viral Culture Detected in a Mild COVID-19 Infection
Authors: Vaught Eric S , Rogers Greg A , Ryan Keith E , Averitt Andrew W , Rice Jeffrey M
Published: April 2021

We describe a case of prolonged shedding of live Severe Acute Respiratory Syndrome Coronavirus, 2 in the setting of a mild novel Coronavirus Disease 2019 (COVID-19) infection in a healthy young adult male. The patient did not require hospitalization or any supplemental oxygen. The viral cultures remained positive 15 days from symptom onset. The extended duration of positive viral culture with his concurrent mild symptomatology is at odds with current CDC and DOD isolation policies for positive COVID-19 patients. This case is important as health agencies around the world grapple with how to advise patients and create protocols for isolation precautions after positive COVID-19 results.
Analytical solutions for radiation-driven winds in massive stars – II. The δ-slow regime
Authors: Araya I , Christen A , Curé M , Cidale L S , Venero R O J , Arcos C , Gormaz-Matamala A C , Haucke M , Escárate P , Clavería H
Published: April 2021

Accurate mass-loss rates and terminal velocities from massive stars winds are essential to obtain synthetic spectra from radiative transfer calculations and to determine the evolutionary path of massive stars. From a theoretical point of view, analytical expressions for the wind parameters and velocity profile would have many advantages over numerical calculations that solve the complex non-linear set of hydrodynamic equations. In a previous work, we obtained an analytical description for the fast wind regime. Now, we propose an approximate expression for the line-force in terms of new parameters and obtain a velocity profile closed-form solution (in terms of the Lambert W function) for the δ-slow regime. Using this analytical velocity profile, we were able to obtain the mass-loss rates based on the m-CAK theory. Moreover, we established a relation between this new set of line-force parameters with the known stellar and m-CAK line-force parameters. To this purpose, we calculated a grid of numerical hydrodynamical models and performed a multivariate multiple regression. The numerical and our descriptions lead to good agreement between their values.