bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of Automatic Controller System for Three Axis 3D Printing Platform
Authors: Ren Hongwei , Luan Yongchao , Dong Xingkun , Zhou Haijun , Chen Xin , Yu Xiaochuan
Published: November 2021

With the development of society and the continuous improvement of the level of automation, automatic three-dimensional work platform is more and more popular, but now the three-dimensional work platform has a single function, and the waste of capacity is a serious problem. Therefore, this paper uses STM32F429 MCU to design a set of replaceable working position of the three axis control platform. The design of the table with replaceable work head, by identifying the ID on the head, change the control mode, enhance the functional diversity of the three-axis platform. In addition, in order to improve the universality of the system, the platform has many external communication interfaces, visual man-machine interface and LAN network communication functions.
Design of On-line Detecting Device for Groove Wear of Elevator Traction Wheel
Authors: Shi Xiaomin , Jia Senjun
Published: November 2021

After the wear of elevator traction wheel, there is a traditional detection method which can measure the geometric dimensions of wheel groove. But this method has low measurement accuracy and cannot accurately reflect the actual profile of wheel groove. By means of the machine vision inspection technology, the profile of the traction wheel groove can be measured, a new detection method is proposed in this paper, and the corresponding measuring device is designed in detail. At the same time, with help of the computer simulation, the processing of the work piece image is used. In this method, the size and profile of the wheel groove of the traction wheel can be measured more accurately and quickly to reflect the actual wear value of the wheel groove.
An Improved Artificial Potential Field Escape Method with Weight Adjustment
Authors: Wang Hongyun , Gao Min , Gao Weiwei , Wang Yi , Zhou Haijun
Published: November 2021

Aiming at the problems of obstacle avoidance and bullet avoidance during the patrol swarm, this paper analyzed the defects of the classical artificial potential field, proposed an adjustable escape method, which establish the relationship between the adjustment coefficient and the distance. This method avoid too large or too small escape force that get the bullet into new local shock problem near the target. Then given the weight calculation and parameter selection method, restricted the escape motion by kinematics according to the constraints in the actual motion. This improved method can effecting solve the problem of avoidance in dynamic and complex environment.
Propagation Characteristics of Pressure Pulsation in Hydraulic Hose
Authors: Meng Yuzhen , Han Lei , Zhao Wenkui , Zhang Lishan
Published: November 2021

Most modern aircraft hydraulic systems use variable plunger pumps. The pulsating flow output is its inherent characteristic. The resulting pressure pulsation often causes serious damage to the energy pipeline system and endangers the lives of the occupants. This paper studies the propagation law of hydraulic oil in hydraulic hoses, fully considers the coupling vibration of hydraulic oil high-pressure fluid and flexible solids of the hose, establishes a fluid-solid coupling vibration model of hydraulic hoses, and uses ANSYS for numerical simulation to study different frequencies and pipe bending. Using ANSYS for numerical simulation to study the influence of different frequencies and pipe bending radii on the amplitude of fluid pressure pulsation, after comparative analysis, the law of fluid pressure pulsation propagation in hydraulic hoses is obtained.
Numerical Simulation of Temporal and Spatial Evolution of Stress Field in Unconsolidated Sandstone Oil Reservoir
Authors: Pei Guihong , Song Jiecheng , Zhang Xiaolong
Published: November 2021

Casing damage in the process of oilfield development is a serious problem, which is affected by geological structure, production technology and many other factors. To prevent casing damage, it is necessary to master the space-time evolution law of reservoir in-situ stress field, to provide support for casing damage prevention. Based on the perseage-stress coupling theory, taking the actual reservoir block as the research object, the change law of the in-situ stress field in unconsolidated sandstone reservoir is obtained through the fluid-solid coupling numerical simulation of the reservoir, and the internal correlation between the stress field and casing damage is analysed. The research results provide theoretical guidance for the formulation of casing damage prevention measures in the research block.
Characterization of Silicon-Photomultipliers for a Cosmic Muon Veto detector
Authors: Jangra M. , Majumder G. , Saraf M. , Satyanarayana B. , Shinde R.R. , Upadhya S.S. , Datar V.M. , Glenzinski D.A. , Bross A. , Pla-Dalmau A. , Zutshi V.V. , Group R.C. , Dukes E.C.
Published: November 2021

A Cosmic Muon Veto (CMV) detector using extruded scintillators is being designed around the mini-Iron Calorimeter detector at the transit campus of the India-based Neutrino Observatory, Madurai for measuring its efficiency at shallow depth underground experiments. The scintillation signal is transmitted through a Wavelength Shifting (WLS) fibre and readout by Hamamatsu Silicon-Photomultipliers (SiPMs). A Light Emitting Diode (LED) system is included on the front-end readout for in-situ calibration of the gain of each SiPM. A characterization system was developed for the measurement of gain and choice of the overvoltage (V
ov) of SiPMs using the LED as well as a cosmic muon telescope. The V
ov is obtained by studying the noise rate, the gain of the SiPM, and the muon detection efficiency. In case of any malfunction of the LED system during the operation, the SiPM can also be calibrated with the noise data as well as using radioactive sources. This paper describes the basic characteristics of the SiPM and the comparison of the calibration results using all three methods, as well as the V
ov of the SiPMs and muon selection criteria for the veto detector.
Isotopic evidence of increasing water abundance and lake hydrological change in Old Crow Flats, Yukon, Canada
Authors: MacDonald Lauren A , Turner Kevin W , McDonald Ian , Kay Mitchell L , Hall Roland I , Wolfe Brent B
Published: November 2021

Lake-rich northern permafrost landscapes are sensitive to changing climate conditions, but ability to track real-time and potentially multiple hydrological responses (e.g. lake expansion, drawdown, drainage) is challenging due to absence of long-term, sustainable monitoring programs in these remote locations. Old Crow Flats (OCF), Yukon, is a Ramsar Wetland of International Importance where concerns about low water levels and their consequences for wildlife habitat and traditional ways of life prompted multidisciplinary studies during the International Polar Year (2007–2008) and led to the establishment of an aquatic ecosystem monitoring program. Here, we report water isotope data from 14 representative thermokarst lakes in OCF, the foundation of the monitoring program, and time-series of derived metrics including the isotope composition of input waters and evaporation-to-inflow ratios for a 13 year period (2007–2019). Although the lakes spanned multiple hydrological categories (i.e. rainfall-, snowmelt- and evaporation-dominated) based on initial surveys, well-defined trends from application of generalized additive models and meteorological records reveal that lakes have become increasingly influenced by rainfall, and potentially waters from thawing permafrost. These sources of input have led to more positive lake water balances. Given the documented role of rainfall in causing thermokarst lake drainage events in OCF and elsewhere, we anticipate increased vulnerability of lateral water export from OCF. This study demonstrates the value of long-term isotope-based monitoring programs for identifying hydrological consequences of climate change in lake-rich permafrost landscapes.
Modelling and Analysis of a Virtual Prototype of a Rotary Machine in MSC.ADAMS
Authors: Sapietová A , Dekýš V , Sapieta M , Jastraban A , Pástor M
Published: November 2021

The article presents an analysis of the virtual model of Laval (Jeffcott) rotor in the software environment MSC.ADAMS. The parameters describing the stability of the rotor operation were monitored and evaluated, i. j. critical angular velocity and trajectory of the rotor center of gravity (orbit). The results were compared with the values measured on the experimental equipment, as well as with the values obtained by analytical calculation. The paper further presents a simulation in which the second critical velocity was reached. The paper further presents a simulation in which the second critical velocity was reached.
Modeling of complex construction problems for randomly changing technological processes
Authors: Knast P. , Kołodziej A. , Konecki K.
Published: November 2021

Modeling of complex construction problems for randomly changing technological processes occurs during the production of rubber compounds. Without a good knowledge of the technology of producing rubber compounds, durable and efficient mixers cannot be designed. The conducted industrial research has been shown that the process of mixing the raw materials varies in time and that the forces acting inside the mixer chamber are distributed randomly. During the mixing process of the chemical components, the position of the force changes inside the mixing chamber. The load on the mixer changes over time - as a result of mixing the raw materials and the pressure of the beater. After feeding the raw materials into the mixing chamber, a big concentrated force is reacted on the ram of the mixer, which over time is transformed into several concentrated forces acting simultaneously. Then, as a result of mixing raw materials, temperature and chemical reactions, a pressure acts on the walls of the chamber and the ram of mixer. The conducted research has proved that the most dangerous, from the point of view of the mechanical durability of the mixer, is the first stage of production, in which the beater is subjected to concentrated force. Then, the compactor deforms much more and it can scratch the surface leading to damage to the mixer. The conducted research allows for a much better understanding of the process and thus to carry out a variant simulation of deformations occurring during operation, and thus to improve the durability of the mixer mechanisms.
Analysis of selected properties of powdered compacts
Authors: Olekšáková D
Published: November 2021

Magnetic materials are large and specific group of materials with interesting properties and useful applications. Some of them have been known for many years, but many important materials have only been discovered in recent decades. It can be expected that many newly discovered materials with specific properties will soon be used in applications in which magnetic materials have been used for a long time, but their properties will be better. The development of new magnetic materials will certainly bring the possibility of their use in such applications in which they have not been used before. This paper contains the review of the results of research focused on the study of soft magnetic ferromagnetic materials. Specifically, they are materials of chemical composition Fe19Ni81 (called Permalloy) and Fe16Ni79Mo5 (called Supermalloy). These materials were prepared in the form of powders by the technique of the mechanical milling. Subsequently, these powders were compacted with aim to prepare a compacted material of the desired shape and size with excellent magnetic properties. This research was focused on the study of the structure and magnetic properties of massive magnetic materials prepared by the compaction of the powders in order to prepare soft magnetic material with excellent properties competing with the material used so far.
The influence of liquid rubber on selected properties of rubber compound and its vulcanizates
Authors: Brigantová S , Pajtášová M , Janík R , Ondrušová D , Ďurišová S
Published: November 2021

The aim of the work was to determine the influence of liquid rubber on selected properties of rubber compound and its vulcanizates. Due to the liquid form of this rubber, it is not possible to completely replace the conventional solid rubber used in the mixture because of problems in further processing. In four experimental tests, we used different amounts of liquid rubber in the recipe together with butadiene-styrene rubber and the compounds we mixed according to the general conditions. We studied the curing characteristics of prepared mixture and we measuremend physical and mechanical properties of study vulcanizates and summarized the individual measured values for each parameter and suggested the greatest importance of the recipe for rubber practice.
Application of biowaste in rubber blend
Authors: Božeková S , Mičicová Z , Ondrušová D , Pajtášová M , Božek M
Published: November 2021

Submitted paper deals with the incorporation of biological waste into the rubber blend and moreover, it is mainly connected with the determination of the influence of this biowaste on the basic properties of the blends and vulcanizate. Wood flour, which comes from the production of wood pellets, was used as the biowaste. Biowaste was used as a filler but also as a plasticizer. The effect of the mentioned biowaste (wood flour) in rubber blend was determined from the aspect of curing characteristics and physical-mechanical properties. In addition, Payne effect was also determined. Achieved results show the possibilities of partial use of biowaste in the rubber blend and provide other research possibilities.
Optimization of the Study Materials Design in the Conditions of the COVID-19 Pandemic
Authors: Knežo D
Published: November 2021

Numerical and statistical methods are frequently used as a research tool in technical fields and therefore are an important part of studies within technical study programmes. The COVID-19 pandemic has affected university education resulting in the distance form of education. Experience has shown that to train the application of numerical and statistical methods as well as to create homework, which is a condition for students to complete their courses, it is important to provide a large number of exercises and tasks. The work describes a model of automated study materials design using computer technology with emphasis on optimizing the design in terms of three optimization conditions: any number of exercises and tasks, minimizing the design time required and a sufficient variety of exercises and tasks. Free Pascal programming language and the LaTeX typographic system were used as the basis for the model.
Modeling the vehicle operational efficiency in the "Vehicle - Infrastructure” system
Authors: Mateichyk V , Smieszek M , Tsiuman M , Symonenko R
Published: November 2021

The article is devoted to the study of vehicle operational efficiency in certain infrastructural environment conditions. The vehicle operational efficiency is evaluated according to dynamic, economic and environmental criteria using a mathematical model of the "Vehicle-Infrastructure" system. The mathematical model describes the main processes in the studied system: the conversion of input energy into mechanical energy of propulsion system, mechanical energy transmission to the vehicle wheels, the conversion of wheels rotation into vehicle translational motion, change of vehicle motion modes and directions according to a given motion law in certain infrastructural environment conditions. The presented structure of the mathematical model contains generalized dependences between the main parameters of the system processes and feedbacks implementing the target functions of thermal control of individual propulsion subsystems and vehicle modes to achieve the desired values of energy consumption and emissions per transport work unit. The results of vehicle operational efficiency evaluation using verified model in the implementation of individual algorithms for thermal development control of propulsion subsystems (engine and catalytic converter) in the heating mode are given.
Design and implementation of a diagnostic system for measuring high-precision reducers
Authors: Kočiško M , Pollák M , Vodilka A , Paulišin D
Published: November 2021

At present, the industry is in a phase where there is an effort to maximize the automation of production processes. In many places, human power is being replaced by automated machines and industrial robots. Automation makes it possible to increase work efficiency, significantly reduce production costs and also increase the quality of the final product. A precondition for increasing the quality of production is to achieve high accuracy of specialized machines and industrial robots, resp. the accuracy of positioning of individual parts. Due to the drive system and the achieved speed, the gear unit includes a gearbox. Reducers used in robotic joints are the most complex subsystems of robots. For very precise applications, the designers will reach for the so-called backlash-free reducers for their characteristic properties (minimum values of backlash in teeth, angular transmission errors, hysteresis and others). Despite many positive properties, high-precision reducers also show their characteristic nonlinearities, which influence the behavior of the whole system and it is so important to know their behavior. Given these facts, this article deals with the design and implementation of mechatronic diagnostic equipment for the identification of nonlinearities, static and dynamic parameters, vibrodiagnostic measurements and measurements of the efficiency of bearing reducers.
Determination of the coefficient of friction in a screw joint loaded with a controlled torque
Authors: Mascenik J
Published: November 2021

The aim of this article is mechanism description for the measuring the friction coefficient in the threads of threaded joint and consecutive experimental measuring of friction coefficient. The coefficient of friction in the threads of a bolt and nut depends on a number of factors, in particular the roughness of the surfaces, the properties of the lubricating film and the angle of the side of the thread. The coefficient is a function of the heat treatment, the quality of the surface protection substance, the size of the screw load and the pitch angle of the thread. The principal parameters of the measuring was fastening torque, which was choose by the torque wrench, axial strength, measured by axial force sensor, and calculated friction coefficient. The friction coefficient was calculated through the use of exponential equation of the torque balance in the screw. The value of the friction coefficient was examined on the threaded joint of size M20 without the plastic lubricants and with the plastic lubricants. Measured values of friction coefficient was close to values listed in the norm and makes argument that plastic lubricants can decrease the friction coefficient in the threads of threaded joint.
The method of kinematic excitation reconstruction based on measured suspension dynamic responses – experimental verification
Authors: Klockiewicz Zbyszko , Ślaski Grzegorz , Pikosz Hubert
Published: November 2021

The paper presents the method of kinematic road excitation reconstruction based on measured suspension dynamic responses and its reconstruction with use of estimated displacements of unsprung mass as a preliminary approximation of kinematic excitation and tracking control system with a PID controller that allows for faithful reconstruction of unsprung mass accelerations and, in turn, kinematic excitations. The authors performed an experimental verification of the method with use of one axle car trailer and measurements of road profile and acquiring signals of suspension dynamics responses. The signal processing methodology and obtained results are presented for random and determined excitations. The necessary requirements to use the method effectively were defined and its limitations were listed.
Sensorless Control of Asynchronous Motor at Low speed
Authors: Duhancik M , Gaspar S , Coranic T
Published: November 2021

The subject of the submitted paper is to provide a detailed description of simulation control of rotor position sensing of an asynchronous motor by an injection method of high-frequency analogue signal on supply signal frequency of up to 5 Hz, i.e., at zero and low speed. In general, contrary to discrete signal injection, the implementation of the method appears to be simpler for continual signal injection aimed at monitoring of asymmetry of rotary electric machines, however, the process of information gathering related to position of monitored asymmetries during signal reaction processing is more complicated. Genuine verification of the method requires designing a mathematical model of a motor including asymmetries caused by rotor grooving and by magnetic core saturation. The asymmetries occurring in asynchronous motors considerably influence the instant value of a stator induction LS. Asymmetries caused by magnetic circuit saturation were identified and eliminated because of inducing the measured signal distortion. The elimination method LMDEM is the method proposed for repressing the asymmetries. The asymmetries caused by rotor grooving are intended to detect the rotor position. In final part, mathematical functions will be used for converting the signal to rotor position.
Analysis of software solutions for creating models by a generative design approach
Authors: Pollák M , Kočiško M , Dobránsky J
Published: November 2021

With the constant development of new technologies and designs, the idea of a generative design approach arose. Generative design allows to create an infinite number of new designs in a relatively short time without the constraints associated with the imagination of the designer. Designs created by a generative design approach create optimized products that meet the specific needs of their end users. The parts created in this way are often lighter, stronger and less expensive in terms of their subsequent production. Generative design software applications are often more intuitive to work with than traditional CAD systems, and no additional knowledge associated with operating the software is required. The main goal of generative design is to save time in the design process, save material by creating optimal structures, and thus save money by developing cost-effective products. The product software only adds material where it is needed, which is typical of the additive production of organic shapes and forms. The product created in this way is more efficient for production compared to the traditional design and production approach. The article points out the current state of development of this rapidly expanding design technology with a description of software solutions used for the implementation of a generative design approach on illustrative examples of created design products.
Testing and simulating the working conditions of an organic material shredders
Authors: Tyszczuk K , Śmigielski G , Domek G
Published: November 2021

The paper presents the results of works carried out by the authors on the design and operation of organic material shredders. It is a widely undertaken research program started many years ago, in recent months devoted to testing the operational wear of a selected shredder and product. Previous research has involved different grinder designs and different ways of disintegrating basic biological materials. In the following years, parameters for different shredded materials were selected for the selected type of knife shredder. After reaching the "most difficult" material for disintegration, the analysis of the design of the shredders and the selection of the system for that particular material was resumed. Tests of structural elements, crucial for the system durability, show the complexity of the grinding process conditions. The selection of key parameters and the simulation of their influence on the course of the process allowed for the development of the process model. Subsequent simulations using the developed model allow you to select the parameters of the shredder in an optimal way.
On the pseudospectra of Schrödinger operators on Zoll manifolds
Authors: Sher David , Uribe Alejandro , Villegas-Blas Carlos
Published: November 2021

We consider non-self-adjoint Schrödinger operators

Δ
+
V

\Delta +V

where

Δ
\Delta

is the Laplace-Beltrami operator on a Zoll manifold

X
X

and

V
∈

C
∞

(
X
,

C

)

V\in C^\infty (X,\mathbb {C})

. We obtain asymptotic results on the pseudo-spectrum and numerical range of such operators.
Predicting superagers by machine learning classification based on the functional brain connectome using resting-state functional magnetic resonance imaging
Authors: Park Chang-hyun , Kim Bori R , Park Hee Kyung , Lim Soo Mee , Kim Eunhee , Jeong Jee Hyang , Kim Geon Ha
Published: November 2021

Superagers are defined as older adults who have youthful memory performance comparable to that of middle-aged adults. Classifying superagers based on the brain connectome using machine learning modeling can provide important insights on the physiology underlying successful aging. We aimed to investigate the unique patterns of functional brain connectome of superagers and develop predictive models to differentiate superagers from typical agers based on machine learning methods. We obtained resting-state functional magnetic resonance imaging (rsfMRI) data and cognitive measures from 32 superagers and 58 typical agers. The accuracies of three machine learning methods including the linear support vector machine classifier (SV), the random forest classifier (RF), and the logistic regression classifier (LR) in predicting superagers were comparable (SV = 0.944, RF = 0.944, LR = 0.944); however, RF achieved the highest area under the curve (AUC; 0.979). An ensemble learning method combining the three classifiers achieved the highest AUC (0.986). The most discriminative nodes for predicting superagers encompassed areas in the precuneus; posterior cingulate gyrus; insular cortex; and superior, middle, and inferior frontal gyrus, which were located in default, salient, and multiple-demand networks. Thus, rsfMRI data can provide high accuracy for predicting superagers, thereby capturing and describing the unique characteristics of their functional brain connectome.
Impact of Maternal Pertussis Antibodies on the Infants’ Cellular Immune Responses
Authors: Orije Marjolein R P , García-Fogeda Irene , Van Dyck Wouter , Corbière Véronique , Mascart Françoise , Mahieu Ludo , Hens Niel , Van Damme Pierre , Cools Nathalie , Ogunjimi Benson , Maertens Kirsten , Leuridan Elke
Published: November 2021

Introduction

Maternal antibody interference of the infant’s humoral immune responses raises some concern to the strategy of maternal Tdap (tetanus, diphtheria, acellular pertussis [aP]) vaccination. This study assessed the impact of maternal Tdap antibodies on the infant’s pertussis-specific T lymphocyte responses following infant vaccination with an aP containing vaccine, in a term and preterm born cohort.

Methods

Heparin samples (±0.5 mL) were conveniently drawn from infants of a Belgian prospective cohort study (N = 79, NCT02511327), including Tdap vaccinated (Boostrix®) and nonvaccinated women (no Tdap vaccine in the last 5 years) that delivered at term or prematurely. Sampling was performed before and 1 month after primary (8-12-16 weeks) and booster vaccination (13 or 15 months) with DTaP-IPV-HB-PRP~T vaccine (Hexyon®). Pertussis toxin (PT)-specific CD3+, CD3+ CD4+ and CD3+ CD8+ lymphoblasts and their cytokine secretions were measured using a flow cytometric assay on whole blood (FASCIA) and multiplex technology (Meso Scale Discovery), respectively.

Results

In total, 57% of all infants were considered PT-specific CD3+ CD4+ lymphoblasts responders after primary and booster vaccination, whereas 17% were CD3+ CD8+ lymphoblast responders. Interferon (IFN)-γ, interleukin (IL)-13, IL-17A, and IL-5 cytokine secretions after primary and booster vaccination were indicative of a mixed T helper (Th) 1/Th2/Th17 cell profile. Lymphoblast and cytokine levels were comparable between term and preterm infants. Nonresponders for IL-13 after booster vaccination had higher maternal PT immunoglobulin G (IgG) levels at birth when compared to responders.

Conclusions

Term and preterm born infants are capable of inducing Th1, Th2, and Th17 responses after aP vaccination, yet maternal vaccination modulate these responses. Evaluation of this effect in larger trials is needed.
Dutch experiences in new partnerships between science and practice in health promotion: toward a fourth-generation university
Authors: Garretsen Henk , van de Goor Ien , van de Mheen Dike
Published: November 2021

For a long time already, attempts have been made to bridge the gap between research and practice. In this respect, society demands that universities should have a bigger social impact. University and society/societal organizations should work together (co-create) during the entire research process, from the articulation of the research question until the implementation of the results. There is controversy about the question whether it is possible for universities to work together with practice and at the same time to retain the academic quality standards. First, this article deals with the question what characteristics are important for universities in order to be able to work together with practice. In this respect, the Dutch scientist Steinbuch came up with a tantalizing idea arguing that universities may take a next step and develop into ‘fourth generation universities’. Second, it is described how a process of co-creation between university and the health promotion practice has been developed, bottom up, at Tranzo, Scientific Center for Care and Wellbeing, Tilburg University, the Netherlands. The ideas developed by Steinbuch and the results of the bottom up processes in Tilburg are combined. Consequences of the Tilburg experiences for the characteristics of a fourth-generation university are discussed as well as consequences for the role of universities in society.
Standalone epicardial left atrial appendage exclusion for thromboembolism prevention in atrial fibrillation
Authors: Cartledge Richard , Suwalski Grzegorz , Witkowska Anna , Gottlieb Gary , Cioci Anthony , Chidiac Gilbert , Ilsin Burak , Merrill Barry , Suwalski Piotr
Published: November 2021

OBJECTIVES

Most strokes associated with atrial fibrillation (AF) result from left atrial appendage thrombi. Oral anticoagulation can reduce stroke risk but is limited by complication risk and non-compliance. Left atrial appendage exclusion (LAAE) is a new surgical option to reduce stroke risk in AF. The study objective was to evaluate the safety and feasibility of standalone thoracoscopic LAAE in high stroke risk AF patients.

METHODS

This was a retrospective, multicentre study of high stroke risk AF patients who had oral anticoagulation contraindications and were not candidates for ablation nor other cardiac surgery. Standalone thoracoscopic LAAE was performed using 3 unilateral ports access and epicardial clip. Periprocedural adverse events, long-term observational clinical outcomes and stroke rate were evaluated.

RESULTS

Procedural success was 99.4% (174/175 patients). Pleural effusion occurred in 4 (2.3%) patients; other periprocedural complications were <1% each. One perioperative haemorrhagic stroke occurred (0.6%). No phrenic nerve palsy or cardiac tamponade occurred. Predicted annual ischaemic stroke rate of 4.8/100 patient-years (based on median CHA2DS2-VASc score of 4.0) was significantly higher than stroke risk observed in follow-up after LAAE. No ischaemic strokes occurred (median follow-up: 12.5 months), resulting in observed rate of 0 (95% CI 0–2.0)/100 patient-years (P < 0.001 versus predicted). Six all-cause (non-device-related) deaths occurred during follow-up.

CONCLUSIONS

Study proved that a new surgical option, standalone thoracoscopic LAAE, is feasible and safe. With this method, long-term stroke rate may be reduced compared to predicted for high-risk AF population.
Antibiotic dispensing knowledge and practice among dispensing staff working in pharmacies near teaching hospitals in Kathmandu Valley, Nepal
Authors: Karki Kshitij , Kumar Neupane Aashish , Raj Singh Devendra
Published: November 2021

Objectives

To assess antibiotic dispensing knowledge and practice among dispensing staff who may or may not have a formal pharmacy qualification working in pharmacies near teaching hospitals in Kathmandu Valley, Nepal.

Methods

A face-to-face cross-sectional study was conducted among 220 dispensing staff. The data were analysed using SPSS 20 to measure descriptive statistics and logistic regressions.

Key findings

Among 220 participants, half of them (50.0%) had inadequate knowledge and slightly less than half of the participants (46.4%) had poor antibiotics dispensing practices.

Conclusions

The government authority should develop and implement a plan for continuous professional education programmes and frequent monitoring of pharmacies to address inadequate antibiotic dispensing knowledge and poor practice.
Evaluation of the Treatment of Aspiration Pneumonia in Hospitalized Children
Authors: Streck Haley L , Goldman Jennifer L , Lee Brian R , Sheets Justin M , Wirtz Ann L
Published: November 2021

Background

Aspiration pneumonia (AP) treatment is variable with limited available guidance on optimal antibiotic choice and duration. This study evaluated the impact of antibiotic regimen and duration on treatment failure for AP in children and correlated the effects of antimicrobial stewardship program (ASP) interventions on treatment duration.

Methods

Hospitalized children who received antibiotics for AP were identified through an existing ASP repository. Diagnosis was confirmed through ASP documentation with either an international classification of diseases 9/10 code or physician diagnosis of AP. Incidence of treatment failure (necrotizing pneumonia, lung abscess, empyema, or retreatment) was compared between patients receiving shorter (≤7 days) vs longer (>7 days) course of antibiotics and between various empiric/final antibiotic regimens utilized. Duration of treatment was evaluated in patients with or without an ASP intervention.

Results

Four hundred and nineteen treatment courses for AP were included. Nineteen episodes (4.5%) of treatment failure were identified. No difference in treatment failure was observed between shorter vs longer courses (8 vs 11 episodes). An aminopenicillin plus beta-lactamase inhibitor was most frequently utilized for both empiric (47.2%) and final treatment (67.5%). Treatment failure rates did not differ with length of intravenous therapy nor empiric/final antibiotic regimen chosen. ASP interventions targeting duration were associated with significantly shorter courses (6.28 vs 7.46 days; P = .04).

Conclusions

Shorter courses of antibiotics did not result in more treatment failure for AP when compared to longer courses. Neither antibiotic choice nor route impacted treatment failure rates. ASPs may optimize the treatment of pediatric AP.
Intestinal necrosis and sigmoid colon obstruction due to bilateral strangulated femoral hernia in a male: a rare surgical and anatomic case report
Authors: Zarokosta Maria , Paraskevas George , Chrysanthou Chrysanthos , Piperos Theodoros , Foutsitzi Aikaterini , Nikas Dimitris , Mariolis-Sapsakos Theodoros
Published: November 2021

Bilateral femoral hernia is a peculiar clinical condition, with female predominance, with only a few cases reported in the literature. There are only two cases of bilateral strangulated femoral hernias, and these occur solely in females. To our knowledge, in the present manuscript, a bilateral strangulated femoral hernia in a male patient is reported for the first time. A 68-year-old male proceeded to the emergency department of our institution with symptoms of bowel obstruction. Abdominal computed tomography, magnetic resonance imaging and subsequent emergency laparotomy revealed obstruction of the sigmoid colon and simultaneous necrosis of several loops of the small intestine due to bilateral strangulated femoral hernia. The operation was uneventful. Despite the scarcity of this clinical condition, surgeons’ awareness is fundamental, in addition to deep knowledge of the pathology and the anatomy of femoral hernias, in order to diagnose and treat adequately strangulated and incarcerated femoral hernias.
DNACPR decisions during Covid-19: An empirical and analytical study
Authors: Bows Hannah , Herring Jonathan
Published: November 2021

Considerable concern has arisen during the Covid pandemic over the use of Do Not Attempt Cardiopulmonary Resuscitation decisions (DNACPRs) in England and Wales, particularly around the potential blanket application of them on older adults and those with learning disabilities. In this article, we set out the legal background to DNACPRs in England and the concerns raised during Covid. We also report on an empirical study that examined the use of DNACPRs across 23 Trusts in England, which found overall increases in the number of patients with a DNACPR decision during the two main Covid ‘waves’ (23 March 2020–31 January 2021) compared with the previous year. We found that these increases were largest among those in mid-life age groups, despite older patients (in particular, older women) having a higher number of DNACPR decisions overall. However, further analysis revealed that DNACPR decisions remained fairly consistent with regard to patient sex and age, with small reductions seen in the oldest age groups. We found that a disproportionate number of Black Caribbean patients had a DNACPR decision. Overall, approximately one in five patients was not consulted about the DNACPR decision, but during the first Covid wave more patients were consulted than pre-Covid.
Eccentricity driving of pebble accreting low-mass planets
Authors: Velasco Romero David A , Masset Frédéric S , Teyssier Romain
Published: November 2021

By means of high-resolution hydrodynamical, three-dimensional calculations with nested-meshes, we evaluate the eccentricity reached by a low-mass, luminous planet embedded in an inviscid disc with constant thermal diffusivity and subjected to thermal forces. We find that a cell size of at most 1/10th of the size of the region heated by the planet is required to get converged results. When the planet’s luminosity is supercritical, we find that it reaches an eccentricity of the order of 10−2–10−1, which increases with the luminosity and broadly scales with the disc’s aspect ratio. Restricting our study to the case of pebble accretion, we incorporate to our model the dependence of the accretion rate of pebbles on the eccentricity. There is therefore a feedback between eccentricity, which determines the accretion rate and hence the planet’s luminosity, and the luminosity, which yields the eccentricity attained through thermal forces. We solve for the steady-state eccentricity and study how this quantity depends on the disc’s turbulence strength parameter αz, on the dimensionless stopping time of the pebbles τs, on the inward mass flux of pebbles and on the headwind (the difference between the gas velocity and the Keplerian velocity). We find that, in general, low-mass planets (up to a few Earth masses) reach eccentricities comparable to the disc’s aspect ratio, or a sizeable fraction of the latter. Eccentric, low-mass protoplanets should therefore be the norm rather than the exception, even if they orbit far from other planets or from large-scale disturbances in the disc.
The Magellanic Edges Survey – II. Formation of the LMC’s northern arm
Authors: Cullinane L R , Mackey A D , Da Costa G S , Erkal D , Koposov S E , Belokurov V
Published: November 2021

The highly-substructured outskirts of the Magellanic Clouds provide ideal locations for studying the complex interaction history between both Clouds and the Milky Way (MW). In this paper, we investigate the origin of a >20° long arm-like feature in the northern outskirts of the Large Magellanic Cloud (LMC) using data from the Magellanic Edges Survey (MagES) and Gaia EDR3. We find that the arm has a similar geometry and metallicity to the nearby outer LMC disc, indicating that it is comprised of perturbed disc material. Whilst the azimuthal velocity and velocity dispersions along the arm are consistent with those in the outer LMC, the in-plane radial velocity and out-of-plane vertical velocity are significantly perturbed from equilibrium disc kinematics. We compare these observations to a new suite of dynamical models of the Magellanic/MW system, which describe the LMC as a collection of tracer particles within a rigid potential, and the SMC as a rigid Hernquist potential. Our models indicate the tidal force of the MW during the LMC’s infall is likely responsible for the observed increasing out-of-plane velocity along the arm. Our models also suggest close LMC/SMC interactions within the past Gyr, particularly the SMC’s pericentric passage ∼150 Myr ago and a possible SMC crossing of the LMC disc plane ∼400 Myr ago, likely do not perturb stars that today comprise the arm. Historical interactions with the SMC prior to ∼1 Gyr ago may be required to explain some of the observed kinematic properties of the arm, in particular its strongly negative in-plane radial velocity.
Nested spheroidal figures of equilibrium I. Approximate solutions for rigid rotations
Authors: Huré J-M
Published: November 2021

We discuss the equilibrium conditions for a body made of two homogeneous components separated by oblate spheroidal surfaces and in relative motion. While exact solutions are not permitted for rigid rotation (unless a specific ambient pressure), approximations can be obtained for configurations involving a small confocal parameter. The problem then admits two families of solutions, depending on the pressure along the common interface (constant or quadratic with the cylindrical radius). We give in both cases the pressure and the rotation rates as a function of the fractional radius, ellipticities, and mass–density jump. Various degrees of flattening are allowed but there are severe limitations for global rotation, as already known from classical theory (e.g. impossibility of confocal and coelliptical solutions, gradient of ellipticity outward). States of relative rotation are much less constrained, but these require a mass–density jump. This analytical approach compares successfully with the numerical solutions obtained from the self-consistent-field method. Practical formula are derived in the limit of small ellipticities appropriate for slowly rotating star/planet interiors.
A high-resolution view of the filament of gas between Abell 399 and Abell 401 from the Atacama Cosmology Telescope and MUSTANG-2
Authors: Hincks Adam D , Radiconi Federico , Romero Charles , Madhavacheril Mathew S , Mroczkowski Tony , Austermann Jason E , Barbavara Eleonora , Battaglia Nicholas , Battistelli Elia , Bond J Richard , Calabrese Erminia , de Bernardis Paolo , Devlin Mark J , Dicker Simon R , Duff Shannon M , Duivenvoorden Adriaan J , Dunkley Jo , Dünner Rolando , Gallardo Patricio A , Govoni Federica , Hill J Colin , Hilton Matt , Hubmayr Johannes , Hughes John P , Lamagna Luca , Lokken Martine , Masi Silvia , Mason Brian S , McMahon Jeff , Moodley Kavilan , Murgia Matteo , Naess Sigurd , Page Lyman , Piacentini Francesco , Salatino Maria , Sarazin Craig L , Schillaci Alessandro , Sievers Jonathan L , Sifón Cristóbal , Staggs Suzanne , Ullom Joel N , Vacca Valentina , Van Engelen Alexander , Vissers Michael R , Wollack Edward J , Xu Zhilei
Published: November 2021

We report a significant detection of the hot intergalactic medium in the filamentary bridge connecting the galaxy clusters Abell 399 and Abell 401. This result is enabled by a low-noise, high-resolution map of the thermal Sunyaev–Zeldovich signal from the Atacama Cosmology Telescope (ACT) and Planck satellite. The ACT data provide the 1.65 arcmin resolution that allows us to clearly separate the profiles of the clusters, whose centres are separated by 37 arcmin, from the gas associated with the filament. A model that fits for only the two clusters is ruled out compared to one that includes a bridge component at >5σ. Using a gas temperature determined from Suzaku X-ray data, we infer a total mass of $(3.3\pm 0.7)\times 10^{14}\, \mathrm{M}_{\odot }$ associated with the filament, comprising about 8 per cent of the entire Abell 399–Abell 401 system. We fit two phenomenological models to the filamentary structure; the favoured model has a width transverse to the axis joining the clusters of ${\sim }1.9\, \mathrm{Mpc}$. When combined with the Suzaku data, we find a gas density of $(0.88\pm 0.24)\times 10^{-4}\, \mathrm{cm}^{-3}$, considerably lower than previously reported. We show that this can be fully explained by a geometry in which the axis joining Abell 399 and Abell 401 has a large component along the line of sight, such that the distance between the clusters is significantly greater than the $3.2\, \mathrm{Mpc}$ projected separation on the plane of the sky. Finally, we present initial results from higher resolution (12.7 arcsec effective) imaging of the bridge with the MUSTANG-2 receiver on the Green Bank Telescope.
Restoration of images with a spatially varying PSF of the T80-S telescope optical model using neural networks
Authors: Bernardi Rafael L , Berdja Amokrane , Guzmán Christian Dani , Torres-Torriti Miguel , Roth Martin M
Published: November 2021

Most image restoration methods in astronomy rely upon probabilistic tools that infer the best solution for a deconvolution problem. They achieve good performances when the point spread function (PSF) is spatially invariant in the image plane. However, this condition is not always satisfied in real optical systems. We propose a new method for the restoration of images affected by static and anisotropic aberrations using Deep Neural Networks that can be directly applied to sky images. The network is trained using simulated sky images corresponding to the T80-S Telescope optical model, a 80-cm survey imager at Cerro Tololo (Chile), which are synthesized using a Zernike polynomial representation of the optical system. Once trained, the network can be used directly on sky images, outputting a corrected version of the image that has a constant and known PSF across its field of view. The method is to be tested on the T80-S Telescope. We present the method and results on synthetic data.
H i IM correlation function from UNIT simulations: BAO and observationally induced anisotropy
Authors: Avila Santiago , Vos-Ginés Bernhard , Cunnington Steven , Stevens Adam R H , Yepes Gustavo , Knebe Alexander , Chuang Chia-Hsun
Published: November 2021

We study the clustering of H i intensity maps (IM) produced from simulations with a focus on baryonic acoustic oscillations (BAOs) and the effects induced by telescope beam smoothing and foreground cleaning. We start by creating an H i catalogue at z = 1.321 based on the Semi-Analytic Galaxy Evolution (SAGE) model applied to the UNIT simulations. With this catalogue, we investigate the relation between model H i and the dark matter haloes and we also study the abundance of H i, $\Omega _\rm{H \small {\rm I}}$, predicted by this model. We then create synthetic H i IM with a nearest-grid-point approach. In order to simulate the telescope beam effect, a Gaussian smoothing is applied on the plane perpendicular to the line of sight. The effect of foreground removal methods is simulated by exponentially damping the largest wavelength Fourier modes on the radial direction. We study the anisotropic 2-point correlation function (2PCF) ξ(r⊥, r∥) and how it is affected by the aforementioned observational effects. In order to better isolate the BAO signal, we study several 2PCF μ-wedges (with a restricted range of orientations μ) tailored to address the systematics effects and we compare them with different definitions of radial 2PCFs. Finally, we discuss our findings in the context of an SKA-like survey, finding a clear BAO signal in most of the estimators here proposed.