E-Learning During Covid-19 Pandemic: An Empirical Research

The COVID-19 pandemic changed our way of life, affected many industries, and had a major impact on education. The paper presents observations and analyses of the challenges raised by the short adaptation time of the learning process and the caused technical, academic, and communication difficulties. An overview of the distinctive features of e-learning during crises, with special attention to communication, feedback and pedagogical approaches in an electronic environment, has been made. Empirical research of the opinion of students and teachers about online learning was conducted. The used research methods are survey and direct observation. Special attention is paid to the results of the survey, which are presented and discussed in detail.

A more gradual positive end-expiratory pressure increase reduces lung damage and improves cardiac function in experimental acute respiratory distress syndrome

Increases in positive end-expiratory pressure (PEEP) or recruitment maneuvers may increase stress in lung parenchyma, extracellular matrix, and lung vessels; however, adaptative responses may occur. We evaluated the effects of PEEP on lung damage and cardiac function when increased abruptly, gradually, or more gradually in experimental mild/moderate acute respiratory distress syndrome (ARDS) induced by Escherichia coli lipopolysaccharide intratracheally. After 24h, Wistar rats (n=48) were randomly assigned to four mechanical ventilation strategies according to PEEP levels: (1) 3 cmH2O for 2-h (control); (2) 3 cmH2O for 1-h followed by an abrupt increase to 9 cmH2O for 1-h (no adaptation time); (3) 3 cmH2O for 30 min followed by a gradual increase to 9 cmH2O over 30 min then kept constant for 1-h (shorter adaptation time); and (4) more gradual increase in PEEP from 3 cmH2O to 9 cmH2O over 1-h and kept constant thereafter (longer adaptation time). At the end of the experiment, oxygenation improved in the shorter and longer adaptation time groups compared to the no-adaptation and control groups. Diffuse alveolar damage and expressions of interleukin-6, club cell protein-16, vascular cell adhesion molecule-1, amphiregulin, decorin, and syndecan were higher in no adaptation time compared to other groups. Pulmonary arterial pressure was lower in longer adaptation time than in no adaptation (p=0.002) and shorter adaptation time (p=0.025) groups. In this model, gradually increasing PEEP limited lung damage and release of biomarkers associated with lung epithelial/endothelial cell and extracellular matrix damage, as well as the PEEP-associated increase in pulmonary arterial pressure.

Application of the Developed Methodology for Transfer of the Temporary Dentures Parameters to a Permanent Prosthesis Supporting on Dental Implants

AIM: The aim of this work is to increase the quality and accuracy of the prostheses manufacture on implants in patients with completely absent dentition, to reduce the number of doctors’ visits to creation of temporary crowns, and more quickly adapt to new prostheses. MATERIALS AND METHODS: A survey and comprehensive treatment of 55 people with complete edentulousness were carried out. Group I consisted of 30 patients who underwent treatment using the developed prototyping method, which took into account the shape of the complete removable dentures and the ratio of the jaws during the manufacture of the prosthesis on implants. The treatment of Group II, consisting of 25 patients, was carried out using a standard technique - after opening the implants, the central ratio of the jaws and the setting of the teeth were re-determined. RESULTS: The treatment of patients with completely absent dentition using the developed prototyping methodology allowed to increase the accuracy of manufacturing temporary dentures based on dental implants, reduce the time of adaptation to the prosthesis and achieve high aesthetic results. CONCLUSION: A prosthesis made using the proposed methodology for transferring the parameters of a temporary dentures to a permanent ones based on dental implants meets all functional and aesthetic requirements, improves the quality of prosthetics, reduces the manufacturing time of the prosthesis, the patient’s adaptation time to it, and is the basis for improving the quality of patient’s life.

Departure Time Choice in Schedule-Based Transit Assignment

This paper investigates existing departure time models for a schedule-based transit assignment and their parametrization. It analyzes the impact of the temporal resolution of travel demand and suggests functions for evaluating the adaptation time as part of the utility of a path. The adaptation time quantifies the time between the preferred and the scheduled departure times. The findings of the analysis suggested that travel demand should be discretized into intervals of 1 min, with interval borders right between the full minute, that is, ±0.5 min. It was shown that longer time intervals led to arbitrary run volumes, even for origin–destination pairs with just one transit line and a fixed headway. Although a linear relationship between adaptation time and adaptation disutility is a common assumption in several publications, it cannot represent certain types of passenger behavior. For some trip purposes, passengers may be insensitive to small adaptation times, but highly sensitive to large adaptations. This requires a nonlinear evaluation function.

Desafíos de la educación digital: experiencias de estudiantes universitarios durante el COVID-19

El objetivo del presente artículo es analizar las experiencias y los desafíos frente a las exigencias de una educación digita ya que coexisten en la llamada educación digital, la conectividad, la creatividad, la colaboración, la convergencia y la comunidad. La investigación es cuantitativa, su diseño es correlacional y con muestreo no probabilístico. La principal ventaja que se identifica es la adaptación, la organización del tiempo y la eficacia para cumplir con las nuevas exigencias de atender las clases en línea y a distancia. Las desventajas son la brecha digital, los recursos limitados para trabajar en línea, y la incertidumbre que genera la propia contingencia sanitaria derivada de la COVID-19. Abstract The objective of this article is the analysis of experiences and challenges in response to demands made by digital education in which connectivity, creativity, collaboration, convergence and community co-exist. The research is quantitative with a correlational design and includes non-probabilistic sampling. The main advantages identified were, adaptation, time management, and efficiency to fulfill the new demands that online distance classes imply. Conversely, the disadvantages found are the digital divide, limited resources which prevent students to work online, and the uncertainty derived from health contingency actions taken against COVID-19.

AP-based CW Synchronization Scheme in IEEE 802.11 WLANs

In this paper, an optimal CW (Contention Window) synchronization scheme is proposed in IEEE 802.11 WLANs. IEEE 802.11 WLANs operates with DCF (Distributed Coordination Function) mode for the MAC (Medium Access Control). In DCF, CW becomes the minimum CW according to the success of data transmissions and increases exponentially due to the collisions. In this situation, the smaller value of the minimum CW can increase the collision probability because stations have higher opportunity to access the medium. On the other hand, the higher value of the minimum CW will delay the transmission, which can result in the network performance degradation. In IEEE 802.11, since the base minimum CW value is a fixed value depending on the hardware or standard, it is difficult to provide the optimal network performance that can be determined by the flexible CW value according to the number of active stations. In addition, the synchronization of optimal CW is required among mobile stations to adapt the network parameters. Especially for the newly joined stations such as moving or turning on stations, they need to adapt the minimum CW value to get the optimal network performance. The shorter the adaptation time is, the better the network performance can maintain. Therefore, in this paper, AP (Access Point) calculates the optimal CW and shares it with mobile stations using beacon and probe response messages for the fast CW synchronization. Extensive simulation results show that the proposed scheme outperforms the previous schemes in terms of the network throughput and adaptation time.

Simulating Human Visual Perception in Tunnel Portals

To study the characteristics of light and dark adaptation in tunnel portals, and to determine the influencing factors in light–dark vision adaptation, basic tunnel lighting and linear design data were obtained. In this study, we used a light-shielded tent to simulate the dark environment of a tunnel, observe the driver recognition time for target objects during the light–dark adaptation process, and analyze the light–dark adaptation time of human vision. Based on the experimental data, we examined the relationships between age, gender, illuminance, and light and dark adaptation times, and established a model for these relationships. The experimental results show that the dark adaptation time is generally longer than the light adaptation time. The dark adaptation time is positively related to age and exhibits a cubic relationship. There is no significant correlation between the light adaptation time and age, but the overall trend is for the light adaptation time to gradually increase with increasing age. There is no correlation between gender and light and dark adaptation times, but there is a notable correlation between light and dark adaptation times and illuminance. When the illuminance ranges from 11,000 to 13,000 lux, the light and dark adaptation times are the longest.

Aligning compound extreme events as defined from climate science and sectoral impact perspectives

<p>This talk will contrast how U.S. decision makers’ impacts-focused perspective on compound extreme events differs from climate science-based perspectives. Examples from around the U.S. will be provided, with an emphasis on cascading impacts that have spanned multiple regions and sectors. The talk will also propose a path forward for synthesizing ‘top-down’ and ‘bottom-up’ approaches to compound extremes, to facilitate adaptation. Time-permitting, preliminary findings from an analysis of sequential humid heat and extreme precipitation over the U.S. may be shown, as a guiding example. The work described reflects a collaboration of scientists funded by NOAA’s Regional Integrated Sciences and Assessments (RISA) program, charged with co-generating ‘useable science’ by working closely with stakeholders.   </p>