scholarly journals Dynamics of SARS-CoV-2 mutations reveals regional-specificity and similar trends of N501 and high-frequency mutation N501Y in different levels of control measures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Santiago Justo Arevalo ◽  
Daniela Zapata Sifuentes ◽  
César J. Huallpa ◽  
Gianfranco Landa Bianchi ◽  
Adriana Castillo Chávez ◽  
...  
Keyword(s):  
High Frequency ◽  
Temporal Dynamics ◽  
Control Measure ◽  
Low Frequency ◽  
Virus Genome ◽  
Control Measures ◽  
Medium Frequency ◽  
Viral Adaptation ◽  
Regional Specificity ◽  
Different Levels

AbstractCoronavirus disease 2019 (COVID-19) is a contagious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This disease has spread globally, causing more than 161.5 million cases and 3.3 million deaths to date. Surveillance and monitoring of new mutations in the virus’ genome are crucial to our understanding of the adaptation of SARS-CoV-2. Moreover, how the temporal dynamics of these mutations is influenced by control measures and non-pharmaceutical interventions (NPIs) is poorly understood. Using 1,058,020 SARS-CoV-2 from sequenced COVID-19 cases from 98 countries (totaling 714 country-month combinations), we perform a normalization by COVID-19 cases to calculate the relative frequency of SARS-CoV-2 mutations and explore their dynamics over time. We found 115 mutations estimated to be present in more than 3% of global COVID-19 cases and determined three types of mutation dynamics: high-frequency, medium-frequency, and low-frequency. Classification of mutations based on temporal dynamics enable us to examine viral adaptation and evaluate the effects of implemented control measures in virus evolution during the pandemic. We showed that medium-frequency mutations are characterized by high prevalence in specific regions and/or in constant competition with other mutations in several regions. Finally, taking N501Y mutation as representative of high-frequency mutations, we showed that level of control measure stringency negatively correlates with the effective reproduction number of SARS-CoV-2 with high-frequency or not-high-frequency and both follows similar trends in different levels of stringency.

scholarly journals Analysis of SARS-CoV-2 mutations reveals three types of temporal dynamics and one is correlated with international travels

2021 ◽  
Author(s):  
Santiago Justo Arevalo ◽  
Daniela Zapata Sifuentes ◽  
Cesar J. Huallpa ◽  
Gianfranco Landa Bianchi ◽  
Adriana Castillo Chavez ◽  
...  
Keyword(s):  
High Frequency ◽  
Relative Frequency ◽  
Temporal Dynamics ◽  
Low Frequency ◽  
Frequency Change ◽  
Medium Frequency ◽  
Human Behaviors ◽  
Viral Adaptation ◽  
Mutation Dynamics

Coronavirus disease 2019 (COVID-19) is a contagious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This disease has spread globally, causing more than 161.5 million cases and 3.3 million deaths. Keeping on the identification, surveillance and the study of the temporal dynamics of mutations with significant representation is central to understand the adaptation of SARS-CoV-2. Furthermore, how lockdown policies influence the dynamics of SARS-CoV-2 mutations is poorly understood. Here, using 1 058 020 SARS-CoV-2 genomes and COVID-19 cases from 714 country-month combinations representing 98 countries, we performed a normalization by COVID-19 cases calculation of relative frequency of SARS-CoV-2 mutations. We found 115 mutations estimated to be present in more than 3 % of global COVID-19 cases and determined three types of mutation dynamics: High-Frequency, Medium-Frequency, and Low-Frequency. Classification of mutations based on temporal dynamics helps to study viral adaptation and can be used to evaluate the effects of human behaviors in the pandemic. For instance, we report a negative and positive correlation of the frequency change of High-Frequency mutations with the level of international movement controls and the number of flight departures, respectively.

How word frequency affects morphological processing in monolinguals and bilinguals

2003 ◽  
Vol 6 (3) ◽  
pp. 213-225 ◽  
Author(s):  
MINNA LEHTONEN ◽  
MATTI LAINE
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Morphological Processing ◽  
Decision Task ◽  
Frequency Range ◽  
Medium Frequency ◽  
Word Forms ◽  
Full Form ◽  
Differential Pattern ◽  
Complex Words

The present study investigated processing of morphologically complex words in three different frequency ranges in monolingual Finnish speakers and Finnish-Swedish bilinguals. By employing a visual lexical decision task, we found a differential pattern of results in monolinguals vs. bilinguals. Monolingual Finns seemed to process low frequency and medium frequency inflected Finnish nouns mostly by morpheme-based recognition but high frequency inflected nouns through full-form representations. In contrast, bilinguals demonstrated a processing delay for all inflections throughout the whole frequency range, suggesting decomposition for all inflected targets. This may reflect different amounts of exposure to the word forms in the two groups. Inflected word forms that are encountered very frequently will acquire full-form representations, which saves processing time. However, with the lower rates of exposure, which characterize bilingual individuals, full-form representations do not start to develop.

Dissociating early and late visual processing via the Ebbinghaus illusion

2016 ◽  
Vol 33 ◽  
Author(s):  
FILIPP SCHMIDT ◽  
ANDREAS WEBER ◽  
ANKE HABERKAMP
Keyword(s):  
Visual Processing ◽  
High Frequency ◽  
Time Course ◽  
Temporal Dynamics ◽  
Low Frequency ◽  
Response Speed ◽  
Ebbinghaus Illusion ◽  
Priming Effects ◽  
Parvocellular Pathway ◽  
The Difference

AbstractVisual perception is not instantaneous; the perceptual representation of our environment builds up over time. This can strongly affect our responses to visual stimuli. Here, we study the temporal dynamics of visual processing by analyzing the time course of priming effects induced by the well-known Ebbinghaus illusion. In slower responses, Ebbinghaus primes produce effects in accordance with their perceptual appearance. However, in fast responses, these effects are reversed. We argue that this dissociation originates from the difference between early feedforward-mediated gist of the scene processing and later feedback-mediated more elaborate processing. Indeed, our findings are well explained by the differences between low-frequency representations mediated by the fast magnocellular pathway and high-frequency representations mediated by the slower parvocellular pathway. Our results demonstrate the potentially dramatic effect of response speed on the perception of visual illusions specifically and on our actions in response to objects in our visual environment generally.

scholarly journals Motoneuron firing patterns underlying fast oscillations in phrenic nerve discharge in the rat

2012 ◽  
Vol 108 (8) ◽  
pp. 2134-2143 ◽  
Author(s):  
Vitaliy Marchenko ◽  
Michael G. Z. Ghali ◽  
Robert F. Rogers
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Medium Frequency ◽  
Adult Rats ◽  
Time Frequency ◽  
High Frequency Oscillations ◽  
Novel Method ◽  
Frequency Coherence ◽  
Fast Oscillations ◽  
First Time

Fast oscillations are ubiquitous throughout the mammalian central nervous system and are especially prominent in respiratory motor outputs, including the phrenic nerves (PhNs). Some investigators have argued for an epiphenomenological basis for PhN high-frequency oscillations because phrenic motoneurons (PhMNs) firing at these same frequencies have never been recorded, although their existence has never been tested systematically. Experiments were performed on 18 paralyzed, unanesthetized, decerebrate adult rats in which whole PhN and individual PhMN activity were recorded. A novel method for evaluating unit-nerve time-frequency coherence was applied to PhMN and PhN recordings. PhMNs were classified according to their maximal firing rate as high, medium, and low frequency, corresponding to the analogous bands in PhN spectra. For the first time, we report the existence of PhMNs firing at rates corresponding to high-frequency oscillations during eupneic motor output. The majority of PhMNs fired only during inspiration, but a small subpopulation possessed tonic activity throughout all phases of respiration. Significant time-varying PhMN-PhN coherence was observed for all PhMN classes. High-frequency, early-recruited units had significantly more consistent onset times than low-frequency, early/middle-recruited and medium-frequency, middle/late-recruited PhMNs. High- and medium-frequency PhMNs had significantly more consistent offset times than low-frequency units. This suggests that startup and termination of PhMNs with higher firing rates are more precisely controlled, which may contribute to the greater PhMN-PhN coherence at the beginning and end of inspiration. Our findings provide evidence that near-synchronous discharge of PhMNs firing at high rates may underlie fast oscillations in PhN discharge.

scholarly journals Training to Detect Phishing Emails: Effects of the Frequency of Experienced Phishing Emails

2019 ◽  
Vol 63 (1) ◽  
pp. 453-457
Author(s):  
Kuldeep Singh ◽  
Palvi Aggarwal ◽  
Prashanth Rajivan ◽  
Cleotilde Gonzalez
Keyword(s):  
False Alarm ◽  
False Alarm Rate ◽  
High Frequency ◽  
Low Frequency ◽  
Response Criterion ◽  
Training Phase ◽  
Medium Frequency ◽  
Hit Rate ◽  
Hit Rates ◽  
Training Protocols

We studied people’s success on the detection of phishing emails after they were trained under one of three phishing frequency conditions, where the proportion of the phishing emails during training varied as: low frequency (25% phishing emails), medium frequency (50% phishing emails) and high frequency (75% phishing emails). Individual base susceptibility to phishing emails was measured in a pre-training phase in which 20% of the emails were phishing; this performance was then compared to a post-training phase in which participants aimed at detecting new rare phishing emails (20% were phishing emails). The Hit rates, False Alarm rates, sensitivities and response criterion were analyzed. Results revealed that participants receiving higher frequency of phishing emails had a higher hit rate but also higher false alarm rate at detecting phishing emails at post-training compared to participants encountering lower frequency levels during training. These results have implications for designing new training protocols for improving detection of phishing emails.

scholarly journals Influence of Autonomic Control on the Specific Intermittent Performance of Judo Athletes

2018 ◽  
Vol 64 (1) ◽  
pp. 99-109
Author(s):  
Bruno T. Campos ◽  
Eduardo M. Penna ◽  
João G.S. Rodrigues ◽  
Mateus Diniz ◽  
Thiago T. Mendes ◽  
...  
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Training Experience ◽  
Specific Performance ◽  
Before And After ◽  
Post Test ◽  
Judo Athletes ◽  
The Mean ◽  
Hrv Analysis ◽  
Different Levels

Abstract Judo is a high-intensity intermittent combat sport which causes cardiac adaptations both morphologically and related to the autonomic nervous system (ANS). Therefore, this study aims to verify the correlation between heart rate variability (HRV) at rest with performance in the Special Judo Fitness Test (SJFT) and whether groups with different RR values at rest show different performance in the SJFT and during post-test recovery. Sixteen judo athletes with 7.2 ± 3.9 years of training experience participated in the study. Before and after the SJFT execution HRV and lactate measurements were conducted. For HRV analysis, we used the mean interval RR, the standard deviation of the RR interval (SDNN), the root mean square of successive differences in RR intervals (RMSSD), the low frequency (LF) and high frequency (HF) in normalized and absolute units. The sample was split into two groups (low RR and high RR) to verify if this variable could differentiate between specific performance. For the SDNN, a significant and moderate correlation (r = 0.53) was found with the total number of throws and throws in the series A (r = 0.56) and B (r = 0.54) and for the RMSSD a correlation with throws during series B (r = 0.59) in the SJFT. However, the groups did not differ in performance and recovery. Therefore, HRV is related to intermittent judo performance; however, it cannot differentiate between judokas at different levels of performance.

scholarly journals Contingency Learning Tracks With Stimulus-Response Proportion

2016 ◽  
Vol 63 (2) ◽  
pp. 79-88 ◽  
Author(s):  
James R. Schmidt ◽  
Jan De Houwer
Keyword(s):  
High Frequency ◽  
Color Word ◽  
Low Frequency ◽  
Contingency Learning ◽  
Response Proportion ◽  
Medium Frequency ◽  
Frequency Condition ◽  
Stimulus Response ◽  
Human Contingency Learning ◽  
Print Color

Abstract. We investigate the processes involved in human contingency learning using the color-word contingency learning paradigm. In this task, participants respond to the print color of neutral words. Each word is frequently presented in one color. Results show that participants respond faster and more accurately to words presented in their expected color. In Experiment 1, we observed better performance for high- relative to medium-frequency word-color pairs, and for medium- relative to low-frequency pairs. Within the medium-frequency condition, it did not matter whether the word was predictive of a currently-unpresented color, or the color was predictive of a currently-unpresented word. We conclude that a given word facilitates each potential response proportional to how often they co-occurred. In contrast, there was no evidence for costs associated with violations of high-frequency expectancies. Experiment 2 further introduced a novel word baseline condition, which also provided no evidence for competition between retrieved responses.

Problematic plant monitoring in Hopewell Culture National Historical Park: 2008–2019

2021 ◽  
Author(s):  
Craig Young
Keyword(s):  
Plant Species ◽  
High Frequency ◽  
Low Frequency ◽  
Size Control ◽  
Medium Frequency ◽  
Rapid Spread ◽  
Exotic Invasive ◽  
Priority Species ◽  
Plant Monitoring ◽  
The Impact

Managers are challenged with the impact of problematic plants, including exotic, invasive, and pest plant species. Information on the cover and frequency of these plants is essential for developing risk-based approaches to managing these species. Based on surveys conducted in 2008, 2011, 2015, and 2019, Heartland Network staff and contractors identified a cumulative total of 51 potentially problematic plant species in Hopewell Culture National Historical Park. Of the 37 species found in 2019, we characterized 7 as very low frequency, 9 as low frequency, 17 as medium frequency, and 4 as high frequency. Of these, midpoint cover estimates of 2 medium frequency and 2 high frequency species exceeded the 10-acre threshold. Because of the number, extent, and cover of problematic plants in the park and the small park size, control efforts should focus on treating high priority species across the entire park. High priority species may include plant species capable of rapid spread, species at low population levels, and species which can effectively be controlled.

scholarly journals Kolokasi Bahasa Inggris Dalam Tugas Akhir Mahasiswa: Analisis Berbasis Frekuensi Dengan Google Sebagai Korpus

2018 ◽  
Vol 1 (2) ◽  
pp. 155
Author(s):  
Tri Nuraniwati ◽  
Ashfa F Lathifah
Keyword(s):  
Academic Writing ◽  
High Frequency ◽  
Low Frequency ◽  
Natural State ◽  
Medium Frequency ◽  
Vocational College ◽  
Search Results ◽  
Linguistic Awareness ◽  
English Program ◽  
Google Search

This study aims to analyze the search results’ frequency of collocations used by students of English Program, Vocational College UGM in their graduating papers (Tugas Akhir) and to show how Google can be used as a practical online corpus for collocations query. Collocations are words that co-occur together in any text and have fixed association. The use of collocations is part of linguistic awareness which determines how language is used in its natural state. Through corpus-based analyses, 1000 collocations are randomly chosen from 10 graduating papers (100 collocations per graduating paper). Using Google search engine, each collocation is entered as key words to find out the frequency of its search hits. The frequency is subsequently categorized into high frequency, medium frequency, and low frequency. From the 1000 collocations, 802 (80.2%) collocations belong to high-frequency collocations, 120 (12%) collocations are in the category of medium frequency, and 78 (7.8%) collocations are categorized as low-frequency collocations. The results indicate that students have shown good level of accuracy in using collocations in their academic writing.        

scholarly journals Influence of Tourism Frequency on Association Model of Ecotourism Action

2018 ◽  
Vol 10 (1) ◽  
pp. 107
Author(s):  
Shwu-Ing Wu ◽  
Hao-Ping Hsu
Keyword(s):  
Significant Influence ◽  
High Frequency ◽  
Perceived Value ◽  
Low Frequency ◽  
Negative Influence ◽  
Positive Influence ◽  
Association Model ◽  
Medium Frequency ◽  
Association Models ◽  
Convenience Sampling

In recent years, many tour operators have entered to the ecotourism market aiming at the trend of ecotourism. In combination of local ecological and environmental resources, these tour operators have promoted a series of themed ecotourism paths and activities to attract tourists from different places. This study conducted literature review and empirical research to explore the influences of consumers’ tourism involvement, tourism values, perception of ecotourism and affection toward ecotourism on attitude toward ecotourism, perceived value of ecotourism, willingness of consumers and actual ecotourism action. Furthermore, association models were established, and the differences on the association models of tourist groups with different tourism frequencies were compared. Convenience sampling was used to survey the consumers who had participated in ecotourism. A total of 787 valid samples were collected. Based on tourism frequency, the respondents were divided into three groups, namely high frequency, medium frequency and low frequency, and the group models were compared. The results showed that (1) the influence of affection toward ecotourism on perceived value of ecotourism is the most significant among the four independent variables in the three tourism groups; (2) for all three tourism groups, tourism involvement has significantly negative influences on the paths of attitude toward ecotourism, and the influence of high-frequency tourism group is the highest; (3) tourism values of the high-frequency tourism group have a significantly negative influence on the path of perceived value of ecotourism while medium-frequency and low-frequency tourism groups have no significant influence; (4) in the medium-frequency tourism group, the affection toward ecotourism has a significantly positive influence on the path of attitude toward ecotourism, and the influence of this group is the highest while high-frequency and low-frequency groups have no significant influence; (5) for all three tourism groups, perceived value of ecotourism has a significantly positive influence on the path of attitude toward ecotourism and the influence of high-frequency tourism group is the highest.

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