Basic Characteristics Research Articles

Cooperative navigation of unmanned aerial vehicle formation with delayed measurement

Abstract This paper focused on the problem of positioning accuracy degradation caused by delayed measurement information in Unmanned Aerial Vehicle (UAV) formation cooperative navigation under complex environments such as cities and hills, and presented a non-synchronous compensation algorithm based on kinematic constraints and constructed a distributed cooperative navigation filter based on the analysis of the basic operating characteristics of inertial devices, satellite receivers, and ranging sensors. In the UAV formation, the leader-UAV is equipped with Real-Time Kinematic (RTK) differential equipment and airborne data link to construct the airborne reference beacons and provide cooperative navigation services for the wingmen-UAV. Firstly, the navigation filtering framework with inertial sensors as the core is established. Secondly, the non-synchronous compensation filter is constructed by using the kinematic constraint model, which compensates and corrects the non-synchronous air-based position of the leader-UAV, and reduces the effect of delayed measurement on the positioning error of the system. Then the fault diagnosis algorithm is utilized to complete the identification and rejection of abnormal range values in the case of Non-Line-of-Sight (NOLS). Finally, the navigation parameters are solved by the Kalman filter. Simulation results show that the non-synchronous compensated filtering proposed in this paper can improve the absolute positioning accuracy by 55%, which effectively improves the cooperative navigation performance and robustness under the presence of random time delay in the measurement information.

Pilot study: Insights into the validity of Opencap to assess knee kinematics during the back squat

Introduction
 Advancements in technology have revolutionized the field of sports science, enabling researchers to gain deeper insights into the biomechanics of athletes' movements (Baca et al., 2022). Among these technological advancements, OpenCap has emerged as a powerful tool for biomechanical analysis (Uhlrich et al., 2023). Integrating OpenCap with other innovative technologies, such as motion capture systems and data analytics, further enhances the understanding of human movement. However, the effective implementation of new technologies requires rigorous scientific validation and a nuanced approach to their comparison with already established techniques. The primary goal of this research is to establish basic characteristics for comparing biomechanical analysis results obtained from OpenCap and VICON.
 Methods
 A total of 3 healthy 23-29-year-old women with a minimum of one year of experience in strength training were recruited for the study. For OpenCap (opensimModel: LaiArnoldModified2017_poly_withArms_weldHand, posemodel: openpose, augmentermodel: v0.2), the system paired cameras of two iOS devices with a web app running on a standard laptop recording videos at 60Hz. A VICON system consisting of 10 cameras (200 Hz, Oxford Metrics Group, Oxford UK) was used for 3D motion analysis. The Plug-In Gait marker set (from the VICON system), comprising 42 markers with a diameter of 16mm, was employed along with two manual markers for tracking the barbell position. Ground reaction forces were measured using two force plates (1000 Hz, Kistler AG, Winterthur, CH). The collected data served as reference data for scaling the models and running OpenSim simulations. Barbell loads were adjusted based on body weight, with loads of 25% or 50% for the free-weight back squat. Each exercise consisted of three cycles of five repetitions, enabling subsequent calculation of average values for further analysis and evaluation.
 Results
 The analysis incorporated 22 valid squats. Statistical mapping revealed significant discrepancies in knee angles between Opencap and the OpenSim model throughout most of the back squat cycle, except from 10 to 35%. The average difference was 16.9 degrees (SD = 18.3 degrees). An RMSE of 24.9 and an ICC 3.1 of 0.503 (p = 0.006076) suggest moderate agreement between the models.
 Discussion/Conclusion
 Ongoing technological advancements are pushing the frontiers of sport biomechanics through groundbreaking innovations. To achieve a comprehensive assessment and comparison of new technologies, it is vital to perform correlation analyses on identical parameters produced by diverse models (Jing et al., 2023). The ICC results indicated a moderate agreement between the models, with the OpenCap model significantly underestimating knee angles. This lesser agreement, as compared to existing literature (Lima et al., 2023), may be attributed to the potential misinterpretation of the barbell by the model. Pending updates from the forthcoming augmenter model v0.3, we advise cautious application of Opencap technology in practical scenarios. However, we believe that with further technological advancement and continued refinement, it has the potential to greatly benefit the field of sports biomechanics.
 References
 Baca, A., Dabnichki, P., Hu, C. W., Kornfeind, P., & Exel, J. (2022). Ubiquitous computing in sports and physical activity—Recent trends and developments. Sensors, 22(21), Article 8370. https://www.mdpi.com/1424-8220/22/21/8370
 Jing, Z., Han, J., & Zhang, J. (2023). Comparison of biomechanical analysis results using different musculoskeletal models for children with cerebral palsy. Frontiers in Bioengineering and Biotechnology, 11, Article 1217918. https://doi.org/10.3389/fbioe.2023.1217918
 Lima, Y., Collings, T., Hall, M., Bourne, M., Diamond, L. (2023). Assessing lower-limb kinematics via OpenCap during dynamic tasks relevant to anterior cruciate ligament injury: A validity study. Journal of Science and Medicine in Sport, 26(Suppl2), S105. https://doi.org/10.1016/j.jsams.2023.08.123
 Uhlrich, S. D., Falisse, A., Kidziński, Ł., Muccini, J., Ko, M., Chaudhari, A. S., Hicks, J. L., & Delp, S. L. (2023). OpenCap: Human movement dynamics from smartphone videos. PLoS Computational Biology, 19(10), Article e1011462. https://doi.org/10.1371/journal.pcbi.1011462
 Acknowledgement
 This study was funded by the Swiss National Foundation (192289).

Association between CD4+T lymphocyte and body composition with physical frailty among elderly HIV-infected patients in Chongqing City

Objective: To identify the association between CD4+T lymphocyte (CD4) counts and physical frailty among HIV-infected people aged 65 years and older, and evaluate whether this association will be modified by the indicators of body composition. Methods: From May to October 2022, 485 elderly HIV-infected patients receiving antiretroviral therapy (ART) were recruited from 7 antiviral treatment sites in Jiangjin District Center for Disease Control and Prevention, Chongqing. The data of basic characteristics (age and gender), living habits (smoking and drinking) and disease history (metabolic diseases, cardiovascular and cerebrovascular diseases, respiratory disease and malignant tumors) were collected through the face-to-face investigation with self-made questionnaires. Fried Frailty Scale was used to evaluate the status of physical frailty. Physical fitness (walking speed, grip strength, height, and weight) and body composition (skeletal muscle mass, body fat mass, and basal metabolic rate) were measured. The antiretroviral treatment data were obtained from the China AIDS Integrated Prevention and Treatment Data information management system. The prevalence of physical frailty was calculated among the HIV-infected patients. The potential effects of CD4 counts on physical frailty were explored by using multivariate logistic regression. Subgroup analyses were repeated in the logistic regression with muscle mass, body fat mass, and other indicators of body composition as subgroup variables to determine whether the association might be modified by body composition. Results: The age of 485 patients were (72±5) years old, of which 48.2% (234 cases) were>70 years old and 70.9% (344 cases) were male, and all of whom had initiated the ART treatment. The prevalence of physical frailty among these patients was 7.4% (36/485). Multivariate logistic regression showed that after adjusting for age, sex, smoking, drinking, body composition index, ART duration, viral load and the number of comorbidities, increased CD4 cell level was associated with decreased prevalent risk of physical frailty among elderly HIV-infected patients. For every increase of 5.0×107 CD4 cells/L, the prevalent risk of physical frailty decreased by 12% [OR (95%CI): 0.88 (0.76-1.01)]. Compared with the low CD4 cell level group, the risk of physical frailty in those with normal CD4 cell level decreased by 69% [OR (95%CI): 0.31 (0.10-0.92)]. Subgroup analysis of body composition indicators showed that the protective effect of normal CD4 cell level on physical frailty was more pronounced in the high skeletal muscle mass and high basal metabolic rate group (Pinteraction<0.05). Conclusion: The prevalence of physical frailty among elderly HIV-infected patients is relatively lower in Chongqing, and the CD4 cell level, skeletal muscle mass and basal metabolic rate are related to physical frailty.

Function and therapeutic prospects of next-generation probiotic Akkermansia muciniphila in infectious diseases.

Akkermansia muciniphila is a gram-negative bacterium that colonizes the human gut, making up 3-5% of the human microbiome. A. muciniphila is a promising next-generation probiotic with clinical application prospects. Emerging studies have reported various beneficial effects of A. muciniphila including anti-cancer, delaying aging, reducing inflammation, improving immune function, regulating nervous system function, whereas knowledge on its roles and mechanism in infectious disease is currently unclear. In this review, we summarized the basic characteristics, genome and phenotype diversity, the influence of A. muciniphila and its derived components on infectious diseases, such as sepsis, virus infection, enteric infection, periodontitis and foodborne pathogen induced infections. We also provided updates on mechanisms how A. muciniphila protects intestinal barrier integrity and modulate host immune response. In summary, we believe that A. muciniphila is a promising therapeutic probiotic that may be applied for the treatment of a variety of infectious diseases.

Cognition-Enhancement Effect of Median Nerve Electrical Stimulation in Patients with Cognitive Impairment: A Retrospective Cohort Study

People with cognitive impairment often face quality-of-life problems and require ongoing support, which has profound consequences for caregivers and society. Noninvasive brain stimulation techniques, such as median nerve electrical stimulation (MNS), have shown promising potentials in improving cognitive ability in patients with cognitive impairment. Therefore, we aimed to investigate the positive effect and safety of MNS in cognitive impairment. Patients diagnosed with cognitive impairment from the hospital record management system of the First Affiliated Hospital of Nanchang University from April 1, 2020, to December 31, 2022, were enrolled. Data on patients' basic characteristics, treatment records, and examination results such as the Mini-Mental State Examination (MMSE), activities of daily living (ADL), and P300 event-related potentials before and after treatment were collected. Overall, 146 patients with cognitive impairment were enrolled, including 71 patients who underwent conventional therapy (standard treatment group) and 75 patients who underwent conventional therapy and MNS operation (active MNS group). Before treatment, there were no differences between the standard treatment and active MNS groups in terms of age, sex, etiology, duration of symptoms before therapy, hospital stay, whether they had undergone surgery, MMSE score, ADL score, and amplitude and latency of the P300 event-related potentials (P > 0.05). After treatment, we observed significant improvements in the MMSE score, ADL score, amplitude of P300, and decreased latency of P300 event-related potentials in both groups compared with before treatment (P < 0.05). In addition, we observed that the active MNS group showed higher MMSE and ADL scores, higher amplitude of P300 event-related potentials, and lower latency of P300 event-related potentials than the standard treatment group after treatment (P < 0.05). Furthermore, no side effects were associated with MNS operation. These preliminary data provide early evidence that MNS may be a positive effect and safe method for promoting the recovery of cognitive ability in patients with cognitive impairment.

Radio News in the Slovak Republic in the 21st Century

The present scientific study focuses on the issue of radio news in the 21st century. The ambition is to evaluate, at the time of writing this study, the current situation concerning news coverage in the most listened radio entities in the Slovak Republic. In this context, the basic characteristics of a public radio broadcaster and a private radio entity are also described. The results focus on the current state of radio news and its diverse interpretation in selected radio entities in Slovakia based on quantitative content analysis. The study details information on the nature of broadcast news in our research sample of the main news programmes of a public and a private radio broadcaster in Slovakia. It also sets out research questions and hypotheses focusing on the representation of news with a domestic and foreign focus, as well as which foreign countries dominate the foreign news coverage, and the themes in the foreign news coverage. The study summarizes the results of the research, generalizes the data, and also formulates conclusions that define radio news in the 21st century. The research section also includes interviews with executives from two selected media entities to support the results of the quantitative content analysis.

Prediction of complete regression in fertility-sparing patients with endometrial cancer and apical hyperplasia: the GLOBAL model in a large Chinese cohort

BackgroundFertility preservation treatment is increasingly essential for patients with apical endometrial hyperplasia (AEH) and early endometrial cancer (EEC) worldwide. Complete regression (CR) is the main endpoint of this treatment. Accurately predicting CR and implementing appropriate interventions during treatment are crucial for these patients.MethodsWe conducted a retrospective study involving 193 patients diagnosed with atypical AEH or EEC, enrolled from January 2012 to March 2022 at our center. We evaluated 24 clinical parameters as candidate predictors and employed LASSO regression to develop a prediction model for CR. Subsequently, a nomogram was constructed to predict CR after the treatment. We evaluated the performance of the nomogram using receiver operator characteristic (ROC) curve and decision curve analysis (DCA) to assess its predictive accuracy. Additionally, we employed cumulative curves to determine the CR rate among patients.ResultsOut of the 193 patients, 173 achieved CR after undergoing fertility preservation treatment. We categorized features with similar properties and provided a list of formulas based on their coefficients. The final model, named GLOBAL (including basic information, characteristics, blood pressure, glucose metabolism, lipid metabolism, immunohistochemistry, histological type, and medication), comprised eight variables identified using LASSO regression. A nomogram incorporating these eight risk factors was developed to predict CR. The GLOBAL model exhibited an AUC of 0.907 (95% CI 0.828–0.969). Calibration plots demonstrated a favorable agreement between the predicted probability by the GLOBAL model and actual observations in the cohort. The cumulative curve analysis revealed varying cumulative CR rates among patients in the eight subgroups. Categorized analysis demonstrated significant diversity in the effects of the GLOBAL model on CR among patients with different total points (p < 0.05).ConclusionWe have developed and validated a model that significantly enhances the predictive accuracy of CR in AEH and EEC patients seeking fertility preservation treatment.

Epidémia bez konca. Čierny kašeľ vo farnosti Detva v 60. rokoch 19. storočia

The article deals with the occurence of whooping cough epidemics using the example of the parish of Detva in the 1860s. However, the problem is more complicated in that the disease appears in the church registers as a cough (tussis), not as a whooping cough (pertussis / tussis convulsiva). Therefore, it was repeatedly verified in the medical literature and sources of the time whenever these terms are correlated. I present how whooping cough is characterized, and how its epidemics manifested themselves in the past. Another part of the text is an analysis of register records, indicating cough, or whooping cough as the cause of death based on records of burials from the parish of Detva in today’s central Slovakia. Victims who perished of a „cough“ died in every year of the analyzed decade. That was also the main reason why I chose this period. My goal was to find out the basic demographic characteristics of the epidemics, such as the average age of the victims, the gender ratio and the proportion of deaths of cough victims to other deceased. Then I would calculate the crude death rate of whooping cough victims and analyzing the seasonality of epidemics. In addition, the research also follow the course of the infection in different parts of the parish, comparing the primary centre of the parish, i.e., the town of Detva, with the periphery of the region, which was made up of estates scattered in the hills.

Establishment and efficiency test of a clinical prediction model of bronchopulmonary dysplasia associated pulmonary hypertension in very premature infants

Objective: To develop a risk prediction model for identifying bronchopulmonary dysplasia (BPD) associated pulmonary hypertension (PH) in very premature infants. Methods: This was a retrospective cohort study. The clinical data of 626 very premature infants whose gestational age <32 weeks and who suffered from BPD were collected from October 1st, 2015 to December 31st, 2021 of the Seventh Medical Center of the People's Liberation Army General Hospital as a modeling set. The clinical data of 229 very premature infants with BPD of Hunan Children's Hospital from January 1 st, 2020 to December 31st, 2021 were collected as a validation set for external verification. The very premature infants with BPD were divided into PH group and non PH group based on the echocardiogram after 36 weeks' corrected age in the modeling set and validation set, respectively. Univariate analysis was used to compare the basic clinical characteristics between groups, and collinearity exclusion was carried out between variables. The risk factors of BPD associated PH were further screened out by multivariate Logistic regression, and the risk assessment model was established based on these variables. The receiver operating characteristic (ROC) area under curve (AUC) and Hosmer-Lemeshow goodness-of-fit test were used to evaluate the model's discrimination and calibration power, respectively. And the calibration curve was used to evaluate the accuracy of the model and draw the nomogram. The bootstrap repeated sampling method was used for internal verification. Finally, decision curve analysis (DCA) to evaluate the clinical practicability of the model was used. Results: A total of 626 very premature infants with BPD were included for modeling set, including 85 very premature infants in the PH group and 541 very premature infants in the non PH group. A total of 229 very premature infants with BPD were included for validation set, including 24 very premature infants in the PH group and 205 very premature infants in the non PH group. Univariate analysis of the modeling set found that 22 variables, such as artificial conception, fetal distress, gestational age, birth weight, small for gestational age, 1 minute Apgar score ≤7, antenatal corticosteroids, placental abruption, oligohydramnios, multiple pulmonary surfactant, neonatal respiratory distress syndrome (NRDS)>stage Ⅱ, early pulmonary hypertension, moderate-severe BPD, and hemodynamically significant patent ductus arteriosus (hsPDA) all had statistically significant influence between the PH group and the non PH group (all P<0.05). Antenatal corticosteroids, fetal distress, NRDS >stage Ⅱ, hsPDA, pneumonia and days of invasive mechanical ventilation were identified as predictive variables and finally included to establish the Logistic regression model. The AUC of this model was 0.86 (95%CI 0.82-0.90), the cut-off value was 0.17, the sensitivity was 0.77, and the specificity was 0.84. Hosmer-Lemeshow goodness-of-fit test showed that P>0.05. The AUC for external validation was 0.88, and the Hosmer-Lemeshow goodness-of-fit test suggested P>0.05. Conclusions: A high sensitivity and specificity risk prediction model of PBD associated PH in very premature infants was established. This predictive model is useful for early clinical identification of infants at high risk of BPD associated PH.

Quantitative analysis of risk assessment indicators for re-introduction of imported malaria in China

To quantitatively analyze the risk indicators of re-introduction of imported malaria in China and their weighting coefficients, so as to investigate the difference in the contribution of risk indicators included in the current risk assessment framework for re-introduction of imported malaria in China to the risk assessment of re-introduction of imported malaria. Publications pertaining to the risk assessment framework for re-introduction of imported malaria in China that reported the risk indicators and their weighting coefficients were retrieved in PubMed, Web of Science, CNKI, Wanfang Data, and VIP with terms of "malaria", "re-introduction/re-transmission/re-establishment", "risk assessment/risk evaluation/risk prediction" from the inception of the database through 3 August 2023, and literature search was performed in Google Scholar to ensure the comprehensiveness of the retrieval. Basic characteristics of included studies were extracted using pre-designed information extraction forms by two investigators, and data pertaining to risk indicators of re-introduction of imported malaria were cross-checked by these two investigators. The risk indicators included in the risk assessment framework for re-introduction of imported malaria in China and their weighting coefficients were visualized with the Nightingale's rose diagrams using the software R 4.2.1, and the importance of risk indictors was evaluated with the frequency of risk indicators included in the risk assessment framework and the ranking of weighting coefficients of risk indicators. In addition, the capability of risk indicators screened by different weighting methods was compared by calculating the ratio of the maximum to the minimum of the weighting coefficients of the risk indicators screened by different weighting methods. A total of 2 138 publications were retrieved, and following removal of duplications and screening, a total of 8 publications were included in the final analysis. In these 8 studies, 8 risk assessment frameworks for re-introduction of imported malaria in China and 52 risk indicators of re-introduction of imported malaria were reported, in which number of imported malaria cases (n = 8) and species of malaria vectors were more frequently included in the risk assessment frameworks (n = 8), followed by species of imported malaria parasites (n = 6) and population density of local malaria vectors (n = 6), and species of local malaria vectors (n = 6), number of imported malaria cases (n = 5) and species of imported malaria parasites had the three highest weighting coefficients (n = 4). The weighting methods included expert scoring method, combination of expert scoring method and analytic hierarchy process, and combination of expert scoring method and entropy weight method in these 8 studies, and the ratios of the maximum to the minimum of the weighting coefficients of the risk indicators screened by the expert scoring method were 1.143 to 2.241, while the ratios of the maximum to the minimum of the weighting coefficients of the risk indicators screened by combination of the expert scoring method and analytic hierarchy process were 34.970 to 162.000. Number of imported malaria cases, species of imported malaria parasites, species of local malaria vectors and population density of local malaria vectors are core indicators in the current risk assessment framework for re-introduction of imported malaria in China. Combination of the expert scoring method and analytic hierarchy process is superior to the expert scoring method alone for weighting the risk indicators.

Statistical evaluation of hard-to-measure surfaces

The main goal of this article will be to find ways to evaluate hard-to-measure surfaces statistically. First, the basic characteristics and rules of surface quality will be described according to the standards ČSN EN 4287, ČSN EN 4288 and ČSN EN ISO 2517-2. Subsequently, the measured values of the roughness parameter Sa (arithmetic average of the height of the measured surface) and Sz (the maximum height of the measured surface) will be compared and evaluated which is the best. These parameters will be described and measured on aluminium plates on which the test surfaces were laser engraved. To evaluate the best surface, statistical methods will be used, such as the EDA methodology (exploratory data analysis), hypothesis testing with normality and outlier tests, and last but not least, cluster or cluster analysis, which compares the similarity of the measured data. This article aims to show the possibilities of surface quality assessment using 3D surface roughness parameters, which are not often used in practice.

Reporting and influencing factors of patient-reported outcomes in acupuncture randomised controlled trials: a cross-sectional study protocol

IntroductionPatient-reported outcomes (PROs) are health reports that come directly from the patients themselves and represented the experience and insights of the patient’s perspective on the impact of the intervention. PROs...

Abstract WP157: Withdrawing and Withholding of Life Sustaining Treatment After Stroke: Understanding the Content of Discussion With Families &amp; Review of Symptoms at End of Life

Background: Stroke kills 160,000 patients every year in the US. Most patients who die with stroke do so in hospital. Little is known about the acute dying process or experience of patients with stroke and their families. Objectives: The goal of this quality improvement project is to better understand the end-of-life process in patients dying with stroke at our institution, focusing on patients who were awake at end of life. Methods: Of patients admitted to our academic medical center in 2022 with stroke who died, we collected basic characteristics and information about reasoning behind WLST and the patient’s condition immediately after WLST. Among those who showed signs of wakefulness (tracking examiner or better), we searched the chart for any documentation of broadly defined goals of care conversations and patient or family symptoms assessed at end of life. Results: Of 525 patients, 118 patients (22.5%) died in hospital. Basic characteristics are listed in Table 1. WLST occurred in 99 patients (84% of decedents), of whom 33 (27.8%) showed signs of wakefulness at time of WLST. None of the patients participated in conversations, and a documented advance directive was followed in 5 (15%). After WLST, patient symptoms most frequently documented by clinicians included dyspnea (n=29), pain (n=18), and restlessness (n=12), but no non-physical symptoms (see Table 2). Family symptoms were not documented. Discussion: At least one quarter of hospital decedents after stroke showed signs of wakefulness, with patient-centered symptoms rarely documented. A standardized, systematic symptom assessment is needed to truly understand signs and symptoms during end-of life for patients with stroke.

The impact of basic health insurance participation characteristics on the health of mobile populations: the mediating role of health service utilization behavior.

It is a pivotal element of China's health system reform to improve the health security of health insurance for the mobile population. Achieving this objective is integral to the success of the reform. The aim of this study was to analyze the impact of different enrollment characteristics of basic health insurance on the health of the mobile population and to investigate the mediating role of health service utilization behavior. This cross-sectional study included 135,372 migrants who participated in the 2018 China Migrants Dynamic Survey (CMDS). Two indicators were employed in this study to assess the characteristics of the mobile population's involvement in basic health insurance-namely, whether or not they participated in local health insurance and the type of health insurance in which they participated. The health status of the mobile population was measured using self-assessed health. Health service utilization behavior was divided into public health service utilization and medical service utilization. Multivariate ordered logistic regression was employed to examine the effect of health insurance on the health of the mobile population. Subsequently, the Bootstrap method was applied to analyze the mediating effect of health service utilization behavior in the relationship between health insurance and the health of the mobile population. Health insurance had a positive impact on health, public health services, and health service utilization among the mobile population. However, enrollment in local health insurance (OR = 1.088, 95% CI = 1.043-1.134) and enrollment in Basic Medical Insurance for Urban Employees (OR = 1.178, 95% CI = 1.090-1.273) were more likely to be associated with higher levels of health and a greater likelihood of receiving health service utilization. The results of the mediating mechanism analysis indicated that health education, health records, family doctor contracting, receiving inpatient services, and being hospitalized locally all played a partially mediating role in the impact of the place of enrollment on health. Regarding the effect of the type of enrollment on health, three types of services-namely, health education, health records, and contracting with a family doctor-played a partially mediating role, while receiving inpatient services and being hospitalized locally did not exhibit a mediating effect. The effect of the type of participation on health is partially mediated. Based on the impact of the different enrolment characteristics of basic health insurance on the health of the mobile population and the mediating role of health service utilization in this impact, furthermore, improvement of health insurance coverage for the mobile population should focus on improving the accessibility of health services, increasing the level of health insurance coverage, mitigating differences in treatment between the different insurance systems, and simplifying the process of transferring the health insurance relationships.

Ray Tracing Meets Terahertz: Challenges and Opportunities

It is very likely that the terahertz (THz) spectrum will be used for the operation of the upcoming 6th-generation (6G) wireless communication systems. This article presents a study for the application of ray tracing (RT) for THz channel modeling. Because of the extremely short wavelengths of THz signals, we argue that signal propagation in the THz spectrum can be precisely modeled by employing RT techniques and thus accurate channel models can be obtained in an efficient manner. We first review recent research and standardization activities related with RT-assisted channel modeling which mainly deal with millimeter-wave (mmWave) applications and to a much lesser extent have been applied the THz spectrum. Then, we present the basic THz wave propagation characteristics, including reflection, scattering, penetration, shadowing as well as signal absorption by atmospheric molecules and tiny particles under different weather conditions. The methodologies for the appropriate construction of target scenarios are presented as well as efficient computational methods for the effective RT operation. Finally, various research and development (R&D) challenges related to RT-based channels for future THz communication systems are identified and possible solutions are highlighted.

Effect of acupuncture on ischaemic stroke in patients with rheumatoid arthritis: a nationwide propensity score-matched study

ObjectiveTo demonstrate that acupuncture is beneficial for decreasing the risk of ischaemic stroke in patients with rheumatoid arthritis (RA).DesignA propensity score-matched cohort study.SettingA nationwide population-based study.ParticipantsPatients with RA diagnosed between...

Numerical Equivalent Acoustic Material for Air-Filled Porous Absorption Simulations in Finite Different Time Domain Methods: Design and Comparison

Extracting the microscopic parameters of a porous material is a complex task, and attempts have been made to develop models that can simulate their characteristics, gathering the least amount of information possible. As a case in point, tests to evaluate macroscopic behaviors such as tortuosity, which depends directly on the microscopic fluid velocities, are highly susceptible to generate errors if the precision of the measurement devices is not correct, and the same goes for the other parameters. For this reason, in this paper, a sound propagation model in porous materials with a rigid frame is presented based on a local theory, which tries to simplify, even more, the way to obtain the basic characteristics of porous materials, such as their absorption coefficient at normal and random incidence, and their normal surface impedance. The proposed linearized equivalent fluid model presents four phenomenological coefficients, which characterize acoustic propagation trough the material. Their values are obtained from the material thickness and a measurement in an impedance tube following the ISO 10534 standard. Thus, what is only required is the measured absorption coefficient, either on one third or one octave bands, to fully represent the acoustic behavior in the finite different in time domain (FDTD) method. The model has been simulated with FDTD in porous and fibrous kernels, and the results show a strong agreement with the laboratory measurements and with the analytical results calculated with well-established semi-phenomenological models.

Deciphering the Nexus: Knowledge, Reality, and Quantum Magnetism

We understand that magnetism has a wave-particle duality due to experiments. Asking the question of what is it that can be known is what led to the experiments. This paper shows the importance of knowing the basic characteristics of everything leads to an easier understanding of existence and should be introduced early in the education curriculum. Everything we are studying has the same basic characteristics, a truly multidisciplinary tool.

Chronic Noise Exposure with Normal Hearing is Related to Adverse Quality of Life and Burnout

Aims and scope: Occupational noise exposure is a well-known factor of hearing loss and other health related problems. Its contribution on burnout and health related quality of life, particularly when there is no hearing loss is less well studied. Herein we aim to study the effect of noise on the responses of normal hearing industrial workers on validated instruments. Methods: 384 industrial workers from three pharmaceutical companies with normal hearing were stratified into two groups: a noise-exposure group (n=195) and a nonexposure group (n=125). In addition to basic demographic characteristics, factors such as smoking, and BMI were examined alongside responses to the Oldenburg Burnout Inventory (OLBI) and SF-36 questionnaire. Findings: The noise-exposure group exhibited a higher prevalence of smokers (p&lt;0.01), a slightly elevated median BMI (p=0.04) and reported more pronounced exhaustion as measured by the OLBI (p=0.03). Furthermore, they exhibited poorer responses in various dimensions of the SF-36 questionnaire, particularly in bodily pain (p&lt;0.01), physical functioning (p=0.03), physical role functioning (p=0.02) and emotional role functioning (p&lt;0.01) scales. Conclusion: Occupational noise exposure, even in the absence of hearing loss, is associated with a higher prevalence of burnout symptoms and an overall reduced health-related quality of life among industrial workers. These insights underscore the need for proactive measures to mitigate noise exposure's adverse impact on employee wellbeing and productivity in noisy work environments, independently of the findings in their audiometric results.

A global perspective on household size and composition, 1970–2020

Households are core units of social organization and reproduction, yet, compared to other areas of demographic research, we have limited understanding of their basic characteristics across countries. Using data from 793 time points and 156 countries in the new CORESIDENCE database, this article provides a comprehensive analysis of global household size and composition trends. The findings reveal that despite significant international variations in household size, ranging from 1.8 in Denmark to 8.4 in Senegal, there is a widespread decline in household size. On average, households have decreased by approximately 0.5 persons per decade. Children contribute to over three-quarters of the observed variability and decline in household size in recent decades. In contrast, the number of other relatives in households has remained relatively stable or has only moderately decreased. While households are becoming more similar in size, their composition is not converging globally to the same extent. These dynamics have macro and micro-level implications for families, societies, and the economy. Further investigation is required to understand the underlying factors driving these transformations and their consequences.