Threshold of Herd Effect for Online Events in China

2015 ◽  
pp. 380-389
Author(s):  
Tieying Liu ◽  
Kai Chen ◽  
Yang Zhong
Keyword(s):  
Herd Effect

scholarly journals Vaccination herd effect experience in Latin America: a systematic literature review

2018 ◽  
Vol 15 (1) ◽  
pp. 49-71 ◽  
Author(s):  
Rodrigo DeAntonio ◽  
Sylvia Amador ◽  
Eveline M. Bunge ◽  
Jennifer Eeuwijk ◽  
David Prado-Cohrs ◽  
...  
Keyword(s):  
Latin America ◽  
Literature Review ◽  
Systematic Literature Review ◽  
Herd Effect

The model of information dissemination on social networks under epidemic-related panic

2021 ◽  
Author(s):  
Fuzhong Nian ◽  
Xin Guo ◽  
JinZhou Li
Keyword(s):  
Social Networks ◽  
Individual Differences ◽  
Infection Rate ◽  
Information Dissemination ◽  
Self Regulation ◽  
Cumulative Effect ◽  
Herd Effect ◽  
Collective Wisdom ◽  
Leading Role

Inspired by infectious disease dynamics and modern psychology, this paper aims at constructing a multi-dimensional function to get the model of information dissemination on social networks under epidemic-related panic base on the characteristics of individual differences and global characteristics, like emotional cumulative effect, herd effect, time-sensitive decline effect, cognitive level, intimacy, personal influence, etc. The results show that the psychological effect has a significant effect on the increase of the spread of panic news; When netizens are in an emotional atmosphere, their emotional self-regulation ability is limited; when the infection rate is relatively low, the characteristics of individual differences play a leading role in affecting the spreading process. When the infection rate is high enough, the herd effect and emotional cumulative effect play a major role in promoting information dissemination; In a society with a higher rate of emotional contact, it is easier to form a kind of collective wisdom, which can help the collective quickly identify rumors. Moreover, in this kind of society, the role of opinion leaders is limited, and timely refutation of rumors can significantly reduce the spread of panic news.

Intelligent English writing system based on fusion of herding effect and artificial intelligence

2020 ◽  
pp. 1-11
Author(s):  
Liu Guifang
Keyword(s):  
Artificial Intelligence ◽  
Training System ◽  
Small Scale ◽  
Traditional Teaching ◽  
Writing System ◽  
Herd Effect ◽  
College English ◽  
English Writing ◽  
Relative Attractiveness ◽  
Information Sharing Mechanism

The use of intelligent college English writing training system will certainly promote the traditional teaching structure and realize a new and efficient English writing teaching mode. On the basis of machine learning and the herd effect algorithm, this article constructs an artificial intelligence-based English intelligent writing system. Moreover, in view of the shortcomings of traditional models and the characteristics of intelligent English writing, this paper proposes an improved algorithm for optimization of swarm particle walking paths. In addition, this article proposes a relative attractiveness to initialize the formation of small-scale groups based on the herd effect. Then, in the process of intelligent writing, by establishing an information sharing mechanism between groups, each group is continuously updated and reorganized according to the relative attractiveness of the group, so that the writing process can be simulated more realistically. From the experimental research, it can be seen that the model constructed in this paper has a certain degree of intelligence.

ENDOGENOUS CROSS CORRELATIONS

2007 ◽  
Vol 11 (S1) ◽  
pp. 124-153 ◽  
Author(s):  
STEPHEN E. SATCHELL ◽  
STEFFI J.-H. YANG
Keyword(s):  
Financial Regulation ◽  
Equity Markets ◽  
Portfolio Diversification ◽  
Current View ◽  
Investment Behavior ◽  
Portfolio Risk ◽  
Herd Effect ◽  
Cross Correlations ◽  
Asymmetric Correlation ◽  
The Relationship

This paper studies the relationship between rational herding and cross correlations in security returns. It demonstrates analytically and numerically that herding, as a temporary, fragile convergence of investment behavior, can endogenously induce asset dependency. Furthermore, there exists a self-reinforcing process, in which market extreme events amplify the herd effect, which further exacerbates asset dependency. Considering the Taiwan and U.K. equity markets, we find that the simulated markets in the presence of herding have results closer to the real patterns of asset dependency than a static model with isolated, noninteracting individuals. Our findings cast doubts on the current view that transparent financial regulation is always desirable. Moreover, this paper finds statistical evidence of asymmetric correlation patterns in both the top 50 stocks in the U.K. and Taiwan equity markets. This suggests that portfolio diversification as a means of managing portfolio risk is unlikely to be effective in periods of extreme losses in these markets.

scholarly journals Herd Immunity in India: A Review

2021 ◽  
Vol 3 (1) ◽  
pp. 18-21
Author(s):  
Sheema Fatima Khan
Keyword(s):  
Basic Reproduction Number ◽  
Reproduction Number ◽  
Natural Infection ◽  
Herd Immunity ◽  
Herd Effect ◽  
Susceptible Population ◽  
Herd Protection ◽  
Cdc Guidelines ◽  
And Control

Herd Immunity is a brilliant solution to tackle and control global pandemics, if taken proper route for immunization such as through vaccination. It is defined as the number of immune individuals against a transmissible virus in a completely susceptible population. The term herd protection or herd effect is the protection to the whole population due to herd immunity. Herd immunity threshold is the minimum proportion of immune population required for herd effect or herd protection. To calculate the threshold, we use basic reproduction number (R0) to measure the rate of transmission of pathogen, in this case SARS-CoV-2. However, a better measure is effective reproduction number (Re). India is major example of herd immunity. Despite strict lockdown and other Covid measure, due to already crowded area the virus could spread fast and to vast majority of people if one of them were to catch it. This explains the steady decline in the number of coronavirus cases in India. At the end, until an approved effective vaccination available, public will still need to follow all the CDC guidelines in order to avoid the large deaths along with natural infection.

scholarly journals Human papillomavirus seroprevalence in pregnant women following gender-neutral and girls-only vaccination programs in Finland: A cross-sectional cohort analysis following a cluster randomized trial

PLoS Medicine ◽  
2021 ◽  
Vol 18 (6) ◽  
pp. e1003588
Author(s):  
Penelope Gray ◽  
Hanna Kann ◽  
Ville N. Pimenoff ◽  
Tiina Eriksson ◽  
Tapio Luostarinen ◽  
...  
Keyword(s):  
Human Papillomavirus ◽  
Randomized Trial ◽  
Vaccination Coverage ◽  
Hpv Vaccination ◽  
Herd Effect ◽  
Entire Study ◽  
Post Vaccination ◽  
Vaccination Programs ◽  
Link Type ◽  
Gender Neutral

Background Cervical cancer elimination through human papillomavirus (HPV) vaccination programs requires the attainment of herd effect. Due to its uniquely high basic reproduction number, the vaccination coverage required to achieve herd effect against HPV type 16 exceeds what is attainable in most populations. We have compared how gender-neutral and girls-only vaccination strategies create herd effect against HPV16 under moderate vaccination coverage achieved in a population-based, community-randomized trial. Methods and findings In 2007–2010, the 1992–1995 birth cohorts of 33 Finnish communities were randomized to receive gender-neutral HPV vaccination (Arm A), girls-only HPV vaccination (Arm B), or no HPV vaccination (Arm C) (11 communities per trial arm). HPV16/18/31/33/35/45 seroprevalence differences between the pre-vaccination era (2005–2010) and post-vaccination era (2011–2016) were compared between all 8,022 unvaccinated women <23 years old and resident in the 33 communities during 2005–2016 (2,657, 2,691, and 2,674 in Arms A, B, and C, respectively). Post- versus pre-vaccination-era HPV seroprevalence ratios (PRs) were compared by arm. Possible outcome misclassification was quantified via probabilistic bias analysis. An HPV16 and HPV18 seroprevalence reduction was observed post-vaccination in the gender-neutral vaccination arm in the entire study population (PR16 = 0.64, 95% CI 0.10–0.85; PR18 = 0.72, 95% CI 0.22–0.96) and for HPV16 also in the herpes simplex virus type 2 seropositive core group (PR16 = 0.64, 95% CI 0.50–0.81). Observed reductions in HPV31/33/35/45 seroprevalence (PR31/33/35/45 = 0.88, 95% CI 0.81–0.97) were replicated in Arm C (PR31/33/35/45 = 0.79, 95% CI 0.69–0.90). Conclusions In this study we only observed herd effect against HPV16/18 after gender-neutral vaccination with moderate vaccination coverage. With only moderate vaccination coverage, a gender-neutral vaccination strategy can facilitate the control of even HPV16. Our findings may have limited transportability to other vaccination coverage levels. Trial registration ClinicalTrials.gov number NCT00534638, https://clinicaltrials.gov/ct2/show/NCT00534638.

scholarly journals 127Topical antibiotics used to prevent infection in the ICU: an accidental natural herd exposure experiment

2021 ◽  
Vol 50 (Supplement_1) ◽  
Author(s):  
James Hurley
Keyword(s):  
Systematic Reviews ◽  
Infection Prevention ◽  
Intervention Group ◽  
Control Group ◽  
Control Groups ◽  
Topical Antibiotic ◽  
Herd Effect ◽  
Icu Patients ◽  
Topical Antibiotics ◽  
Prevention Methods

Abstract Background Multiple studies of topical antibiotics applied to ICU patients appear to show potent infection prevention effects versus studies of other interventions. However, the effect is less apparent for studies using non-concurrent (NCC) versus concurrent controls (CC) implying the possibility of a herd effect. Methods 206 studies of infection prevention among ICU patients, sourced from 15 systematic reviews were stratified into those using topical antibiotics with NCC versus with CC versus studies of other prevention methods. The event rates were summarised using generalized estimating equations and compared to other studies without an intervention (literature benchmark). Results The summary effect sizes for pneumonia and mortality prevention derived in the systematic reviews were replicated. The mean ICU mortality incidence for topical antibiotic study CC control groups (28.5%; 95% CI, 25.0-32.3; n = 41) is higher versus a literature benchmark (23.7%; 19.2%-28.5%; n = 34), versus NCC control groups (23.5%; 19.3-28.3; n = 14) and versus topical antibiotic intervention groups (24.4%; 22.1 – 26.9; n = 62). In meta-regression models adjusted for group mean age and publication year, CC group membership within a topical antibiotic study remains associated with higher mortality (p = 0.027). Conclusions Within topical antibiotic studies, the CC control group mortality incidences are inexplicably high, whereas the intervention group incidences are paradoxically similar to a literature-derived benchmark. Key messages An adverse herd effect is apparent for topical antibiotics used to prevent infection among ICU patients.

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