Mathematical Modeling to Perform an Analysis of Social Isolation Periods in the Dissemination of COVID-19

The outbreak of COVID-19 has made scientists from all over the world do not measureefforts to understand the dynamics of the disease caused by this coronavirus. Several mathematical models have been proposed to describe the dynamics and make predictions. This work proposes a mathematical model that includes social isolation of susceptible individuals as a strategy of suppression and mitigation of the disease. The Susceptible-Infectious-Isolated-Recovered-Dead (SIQRD) model is proposed to analyze three important issues about the dynamics of the disease taking into account social isolation: when the isolation should begin? How long to keep the isolation? How to get out of this isolation? To get answers, computer simulations are provided and their results discussed. The results obtained show that beginning social isolation on the 10th or 15th days, after confirmation of the 50th case, and with 70% of the population in isolation, seems to be promising, since the infected curve does not grow much until it enters the isolation and remains at a stable level during the isolation. On the other hand an abrupt release of the social isolation will imply a second peak of infected individuals above the first one, which is not desired. Therefore, the release from social isolation should be gradual.

The Effects of 8 Weeks TRX Exercises and Core Stability in the Stable Level on the Landing Pattern, the Stability of the Core Area and Balance of Girls Football Players

Background and Aims: This study aimed at the effects of 8 weeks TRX exercises and core stability exercises in the stable level on the landing pattern, the stability of the core area, and the balance of girls football players. Methods: Thirty athletes with trunk defects were screened by Tuck Jump test and selected as a statistical sample. Finally, assigned to two groups of 15 subjects at a stable level and varying level training. Both groups participated in pretest and post-test. Both groups training sessions for 8 weeks and three weeks each week on core stability training at both sustained (stable) and unstable (TRX). This study used the core stability practice protocol in the training section at a stable and unstable level. The static and dynamic balance were evaluated by BESS and Y tests, respectively. McGill’s endurance tests also evaluated the endurance of the core region. In addition, landing mechanics were assessed using the Landing Error Score System test. ANCOVA test was used to compare the differences between the research variables by two types of training. The stability of the core body was used in two groups of training (stable and TRX) and a t-test for correlating the changes within the group. Results: The results of the analysis of t-test showed that in the results of the stable training (P≤0.001) and TRX (P≤0.001) effect on score of the error of landing error, LESS, flexion 60 °, Sorensen, Right Plank, static balance and total dynamic balance score. In the post-test, there are significant differences between the two groups in the TRX and stable levels in LESS, Sorensen, static balance in the state stand on two legs on a soft surface and stand in the Tandem on a soft surface (P≤0.05). Conclusion: the results of this study showed that the use of core stability training at a stable and unstable level by helping to improve the landing jump activity, as well as improving muscular balance and endurance, can be eliminated by modifying some of the risk factors associated with an ACL injury to prevent Lower limb non-limiting injury in athletes with trunk defects.

Dramatic Increases in Telehealth-Related Tweets during the Early COVID-19 Pandemic: A Sentiment Analysis

The COVID-19 pandemic resulted in a large expansion of telehealth, but little is known about user sentiment. Tweets containing the terms “telehealth” and “telemedicine” were extracted (n = 192,430) from the official Twitter API between November 2019 and April 2020. A random subset of 2000 tweets was annotated by trained readers to classify tweets according to their content, including telehealth, sentiment, user type, and relation to COVID-19. A state-of-the-art NLP model (Bidirectional Encoder Representations from Transformers, BERT) was used to categorize the remaining tweets. Following a low and fairly stable level of activity, telehealth tweets rose dramatically beginning the first week of March 2020. The sentiment was overwhelmingly positive or neutral, with only a small percentage of negative tweets. Users included patients, clinicians, vendors (entities that promote the use of telehealth technology or services), and others, which represented the largest category. No significant differences were seen in sentiment across user groups. The COVID-19 pandemic produced a large increase in user tweets related to telehealth and COVID-19, and user sentiment suggests that most people feel positive or neutral about telehealth

THE INTRODUCED STRAWBERRY (FRAGARIA×ANANASSA DUCH.) VARIETIES AS A PROMISING BREEDING MATERIAL

The integrated assessment of introduced strawberry varieties was held in order to identify the gene sources with high level economically important characters for their use in breeding. The biological objects of research were 69 strawberry accessions. As a result of a long-term comprehensive assessment of the genetic collection of introduced strawberry varieties according to the main economically valuable traits in various weather conditions, a source with the highest and stable level of a complex of priority traits was identified. This is the variety Maya with a large-fruited (>25 g) and high productivity (>500 g/plant). Sources of very early (+5 days, Flair variety) and late (-16 days, Malwina variety) ripening periods introduced from the Netherlands have been revealed. The study of everbearing varieties made it possible to identify the variety San Andreas (USA) as source with the most stable level of the multiple fruiting trait regardless of the duration of the photoperiod. All of the above sources are characterized by a number of valuable features that meet the requirements of the consumer market: pulp density, gloss on the surface, high marketability during transportation and dessert taste. The response of identified varieties to low temperature stressors in prewinter and winter periods showed a wide reaction rate and a high regeneration ability to plant biomass.

Psychophysiological features of solving mathematical examples with fractions as adaptability markers to the cognitive load

This study is devoted to identifying a solution algorithm for standard fractions as one of the tasks that allow investigating the level of human adaptability to the cognitive load. The influential factor for a successful solution was the number of stages, and for an unsuccessful one - their duration. It was revealed that the solution success/failure correlated with the spectral power values and ratio in the theta- and alpha-diapasons of the EEG. The successful solution is accompanied by the maintenance of a stable level of theta-diapason and desynchronization in the alpha-diapason. The unsuccessful solution is characterized by an increase in the theta-diapason power, its shift to the frontal zones, and a lack of alpha-desynchronization.

EMI Noise Reduction of DC-DC Switching Converters with Automatic Output Ripple Cancellation

This paper proposes new EMI reduction technologies and automatic output voltage ripple cancellation method for the PWM buck converter with voltage-mode or current-mode and the ripple-controlled converters. Genenrally, modfying the clock frequeny is effective to reduce the EMI noise, but it may increase the output ripple substantially. We have developed techniques to cancel the increased ripple by modifying the slope of the saw-tooth signal or current of the ripple injection circuit. The EMI spectrum of the operating frequency is reduced by more than 15dB and the modified large ripple is canceled to the stable level.

Evaluation of the Stability and Suitable Scale of an Oasis Irrigation District in Northwest China

Oases support human activities in arid and semiarid regions, and their stability is important for regional sustainable development and water resource management. Water consumption is the major factor affecting the stability of oases. On the basis of remote sensing images, evaporation and socioeconomic data, this study first evaluates the stability of the Dunhuang Oasis against the expansion of an oasis irrigation district and planting structure changes from 1987 to 2015. Next, it calculates a suitable area of the oasis irrigation district using water–energy balance theory. The results are as follows: (1) During the 1987–2015 period, with the expansion in the oasis irrigation area, the planting structure underwent a marked transformation from food crops to cash crops to orchards. Water consumption pattern likewise changed considerably. (2) The stability of the Dunhuang Oasis continued to weaken from 0.54 in 1987 until it reached a dangerously unstable level of 0.17 in 2010. With the implementation of water-saving measures and a water-transfer project, the stability of the Dunhuang Oasis irrigation district increased to a metastable level of 0.22 in 2015. (3) Setting the stability are 0.5 of a stable level and 0.75 of an extremely stable level, and the oasis irrigation district should be impractical and reduced by 168 and 241 km2 to attain a suitable oasis ecosystem scale. Hence, at present, the water-transfer project is the most practical way to increase allocated water resource to the oasis irrigation district for improving its stability.

Changes in production and reproduction traits in population of the Slovak Spotted Cattle

The study aimed to examine the analyses of the trend in the numbers of dairy cows, production and reproductive traits in the population the Slovak Spotted cattle for period 2010 to 2019. The number of Slovak Spotted dairy cows is maintained on a relatively stable level in recent years. There was a decrease in the number of animals (12 428 in 2010), but not as strong as after 1990 (85 518). From 2017 number of animals is rising from 14,062, to 14,150 (2018) and 14,627 (2019), respectively. As compared to 2010 an increase of 13.15% in 2017, 13.86% and 17.68%, in 2018 and 2019 respectively was observed. Population size raised from 113.15% (2017) to 117.68% in 2019 respectively. The average annual increase in milk production between the years 2010 to 2019 was + 157.5 kg of milk (total 1,575 kg of milk), + 5.8 kg of fat (total 58 kg of fat) and + 6.1 kg of protein (total 61 kg of protein). Positive growth of milk production in recent years is slightly comparable with the trend of breeding improvement.

PROTEST MOODS OF THE REGION'S RESIDENTS AS A MANIFESTATION OF DESTRUCTIVE FORMS OF CIVIC ACTIVITY

The article analyzes the protest moods of residents of the Vologda region in the context of the development of civil activity of the population. The main trends of protest potential in various socio-demographic categories are considered, and the most significant factors affecting the formation of protest socio-political moods of the population of the region are determined. The research is based on the results of regular monitoring of public opinion conducted by the Center of the Russian Academy of Sciences in the Vologda region. It is concluded that in the period from 2008 to 2019 the protest potential of residents of the Vologda region remains at a relatively stable level. The highest indicators of potential protest activity are the categories of the population that negatively characterize the socio-economic and political situation in the country and region, are dissatisfied with their own financial situation, do not approve of the activities of government structures, and experience negative emotions. Particular attention is drawn to the significant share of potential participants in protest actions among those who demonstrate low indicators of civil participation. Protest moods do not contribute to the development of conventional activity of citizens, prevent the consolidation and solidarity of the population. In this context, the protest potential acts as a destructive form of civil activity of the population.