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Background: A measles outbreak involving 60 cases occurred in Yamagata, Japan in 2017. Using two different mathematical models for different datasets, we aimed to estimate measles transmissibility over time and explore any heterogeneous transmission patterns. Methods: The first model relied on the temporal distribution for date of illness onset for cases, and a generation-dependent model was applied to the data. Another model focused on the transmission network. Using the illness-onset date along with the serial interval and geographical location of exposure, we reconstructed a transmission network with 19 unknown links. We then compared the number of secondary transmissions with and without clinical symptoms or laboratory findings. Results: Using a generation-dependent model (assuming three generations other than the index case), the reproduction number (R) over generations 0, 1, and 2 were 25.3, 1.3, and

This work explores deriving transmissibility functions for a missile from a measured location at the base of the fairing to a desired location within the payload. A pressure on the outside of the f...

Relationships between viral load, severity of illness, and transmissibility of virus are fundamental to understanding pathogenesis and devising better therapeutic and prevention strategies for COVID-19. Here we present within-host modelling of viral load dynamics observed in the upper respiratory tract (URT), drawing upon 2172 serial measurements from 605 subjects, collected from 17 different studies. We developed a mechanistic model to describe viral load dynamics and host response and contrast this with simpler mixed-effects regression analysis of peak viral load and its subsequent decline. We observed wide variation in URT viral load between individuals, over 5 orders of magnitude, at any given point in time since symptom onset. This variation was not explained by age, sex, or severity of illness, and these variables were not associated with the modelled early or late phases of immune-mediated control of viral load. We explored the application of the mechanistic model to identify measured immune responses associated with the control of the viral load. Neutralising antibodies correlated strongly with modelled immune-mediated control of viral load amongst subjects who produced neutralising antibodies. Our models can be used to identify host and viral factors which control URT viral load dynamics, informing future treatment and transmission blocking interventions. Supplementary Information The online version contains supplementary material available at 10.1186/s12916-021-02220-0.

Declared as a pandemic on March 11, 2020, COVID -19 has made it essential for the entire world to control and ensure safety measures for such infections in the future. To take any measures, one must be sure of the route of transmission of the agent causing Pandemic. With so many controversies in its mode of spread, COVID-19 has raised questions for the researchers to confirm its various modes of spread. Many of these modes can be overlooked; it is necessary to emphasize and illustrate them. The aim of this paper is to provide a brief overview of the various modes of COVID-19 transmission. According to the published literature, COVID-19 is primarily transmitted from person to person through oral and respiratory aerosols, with droplets from the virus-infected environment playing a minor role in disease transmission. The infection is particularly dangerous for healthcare workers and the elderly with comorbidities.

This paper presents an output-only structural damage identification methodology by combining the concept of information entropy and transmissibility function. Information entropy quantifies complexity change of structural behavior induced by damage. However, many of the real-life structures are under random input excitations that impose complexity to the structural response. The complexity change induced by the random input may be misinterpreted as damage; thus, the inverse transmissibility function (ITF) is used to eliminate the influence of random input excitation on the complexity change. Damage index is introduced by calculating the entropy of the ITF, and damage identification ability of the ITF-based damage index is compared to the acceleration and impulse response function. The proposed methodology is studied on a numerical and a standard experimental dataset to identify damage presence, type and severity. A multi-layer perceptron neural network is implemented to classify the damaged samples in the experimental dataset, and different damage indices are compared according to the classification results. The case studies validated the effectiveness and robustness of this novel damage identification methodology.

The novel coronavirus (COVID-19) outbreak has left a major impact on daily lifestyle and human activities. Many recent studies confirmed that the COVID-19 pandemic has human-to-human transmissibility. Additional studies claimed that other factors affect the viability, transmissibility, and propagation range of COVID-19. The effect of weather factors on the spread of COVID-19 has gained much attention among researchers. The current study investigates the relationship between climate indicators and daily detected COVID-19 cases in Saudi Arabia, focusing on the top five cities with confirmed cases. The examined climate indicators were temperature (°F), dew point (°F), humidity (%), wind speed (mph), and pressure (Hg). Using data from Spring 2020 and 2021, we conducted spatio-temporal correlation, regression, and time series analyses. The results provide preliminary evidence that the COVID-19 pandemic spread in most of the considered cities is significantly correlated with temperature (positive correlation) and pressure (negative correlation). The discrepancies in the results from different cites addressed in this study suggest that non-meteorological factors need to be explored in conjunction with weather attributes in a sufficiently long-term analysis to provide meaningful policy measures for the future.

Geodesic domes are 3D reticulated structures used to cover large areas. As lightweight structures, they are sensible for dynamic effects. The structural behaviour of domes is affected by the kind of connections between their members. Semi -rigid joints produce loss of stiffness compared with rigid joints. Dynamic tests may capture the effect of semi-rigid joints. The objective of this work is to conduct both static and dynamic tests on a Geodesic Dome at the laboratory scale and compare the results with a linear elastic FE model. The research method involved designing, building and testing a prototype constructed of aluminum wit h overall dimensions of 2000 mm in diameter and 800 mm in height. A 3D finite element model was developed using beam and shell elements. Experimental and numerical results were compared in terms of displacements and frequencies. Load—displacement curves are presented for the static loading. The dynamic behaviour is evaluated by hitting an impact hammer on members and nodes to allow measurement of accelerations. An FFT technique is used to determine the frequency spectrum. The results show that the laboratory prototype presented about 20% less stiffness than predicted by the linear elastic numerical model. The difference is attributed to the transmissibility condition between nodal connectors and emphasizes the influence of semi-rigid joints. Despite being largely used to assess dome structures, standard FE models are shown to be insufficient in capturing local non-linearities.

A novel method is proposed based on the transmissibility concept and matrix regularization for indirectly measuring the structural responses. The inputs are some measured responses that are obtained via physical sensors. The outputs are the structural responses corresponding to some critical locations where no physical sensors are installed. Firstly, the transmissibility concept is introduced for expressing the relationship between the measured responses and the indirectly measured ones. Herein, a transmissibility matrix is formulated according to the theory of force identification under unknown initial conditions. Then, in order to reduce the size of the transmissibility matrix, structural responses are reshaped in a form of a matrix by using the concept of moving time windows. According to the matrix form of input-output relationship, indirect reconstruction of responses is boiled down to an optimization equation. Since inverse problem may be ill-conditioned, matrix regularization such as F-norm regularization is then recommended for improving the optimization problem. Herein, the penalty function is defined by using a weighted sum of two F-norm values, which correspond to the estimated responses of physical sensors and the ones of the concerned critical locations, respectively. Numerical simulations and experimental studies are finally carried out for verifying the effectiveness and feasibility of the proposed method. Some results show that the proposed method can be applied for indirectly measuring the responses with good robustness.

The genomic variations of SARS-CoV-2 continue to emerge and spread worldwide. Some mutant strains show increased transmissibility and virulence, which may cause reduced protection provided by vaccines. Thus, it is necessary to continuously monitor and analyze the genomic variations of SARS-COV-2 genomes. We established an evaluation and prewarning system, SARS-CoV-2 variations evaluation and prewarning system (VarEPS), including known and virtual mutations of SARS-CoV-2 genomes to achieve rapid evaluation of the risks posed by mutant strains. From the perspective of genomics and structural biology, the database comprehensively analyzes the effects of known variations and virtual variations on physicochemical properties, translation efficiency, secondary structure, and binding capacity of ACE2 and neutralizing antibodies. An AI-based algorithm was used to verify the effectiveness of these genomics and structural biology characteristic quantities for risk prediction. This classifier could be further used to group viral strains by their transmissibility and affinity to neutralizing antibodies. This unique resource makes it possible to quickly evaluate the variation risks of key sites, and guide the research and development of vaccines and drugs. The database is freely accessible at www.nmdc.cn/ncovn.

The number of COVID-19 confirmed cases rapidly grew since the SARS-CoV-2 virus was identified in late 2019. Due to the high transmissibility of this virus, more countries are experiencing the repeated waves of the COVID-19 pandemic. However, with limited manufacturing and distribution of vaccines, control measures might still be the most critical measures to contain outbreaks worldwide. Therefore, evaluating the effectiveness of various control measures is necessary to inform policymakers and improve future preparedness. In addition, there is an ongoing need to enhance our understanding of the epidemiological parameters and the transmission patterns for a better response to the COVID-19 pandemic. This review focuses on how various models were applied to guide the COVID-19 response by estimating key epidemiologic parameters and evaluating the effectiveness of control measures. We also discuss the insights obtained from the prediction of COVID-19 trajectories under different control measures scenarios.

Mycobacterium tuberculosis is a clonal pathogen proposed to have co-evolved with its human host for millennia, yet our understanding of its genomic diversity and biogeography remains incomplete. Here we use a combination of phylogenetics and dimensionality reduction to reevaluate the population structure of M. tuberculosis, providing an in-depth analysis of the ancient Indo-Oceanic Lineage 1 and the modern Central Asian Lineage 3, and expanding our understanding of Lineages 2 and 4. We assess sub-lineages using genomic sequences from 4939 pan-susceptible strains, and find 30 new genetically distinct clades that we validate in a dataset of 4645 independent isolates. We find a consistent geographically restricted or unrestricted pattern for 20 groups, including three groups of Lineage 1. The distribution of terminal branch lengths across the M. tuberculosis phylogeny supports the hypothesis of a higher transmissibility of Lineages 2 and 4, in comparison with Lineages 3 and 1, on a global scale. We define an expanded barcode of 95 single nucleotide substitutions that allows rapid identification of 69 M. tuberculosis sub-lineages and 26 additional internal groups. Our results paint a higher resolution picture of the M. tuberculosis phylogeny and biogeography., Mycobacterium tuberculosis is a clonal pathogen that has co-evolved with humans for millennia. Here, Freschi et al. reevaluate the population structure of M. tuberculosis, providing an in-depth analysis of the ancient Indo-Oceanic Lineage 1 and the modern Central Asian Lineage 3, and expanding our understanding of Lineages 2 and 4.

The beam-like structures commonly exist in engineering systems and there are many critical issues relevant to fault diagnosis of those structures. Noticeably, among all other existing methods, transmissibility function-based diagnostic methods, providing much more sensitive damage indexes, are frequently applied and extensively studied, and it is thus meaningful to have a thorough review on most recent advance and related technical difficulties. This paper is, therefore, to present a comprehensive review on this topic for those engineering-oriented beam-like structures, focusing on fundamental theory, critical fault properties and potential applications, respectively. According to different transmissibility function-based features, existing methods are classified into several categories, i.e. general linear transmissibility function, general nonlinear transmissibility function, generalized frequency response function and the second-order output spectrum. With a chain-type multi-degree-of-freedom model with additional connections used for analysing dynamics of beam-like engineering structures, essential topics of these methods including types of transmissibility functions, damage indexes and procedures are discussed in detail. Moreover, the effectiveness, merits and demerits are illustrated by the numerical and experimental results, respectively. It should be noted that some methods discussed here can be readily extended and applied to diagnosis of other plate-like and rotor-like, etc., engineering structures. Apart from fault detection and localization, more sensitive transmissibility function-based damage indicators providing severity and residual life of damaged structures would be further development topics in this area.

This work aims to develop a scale transfer methodology in highly heterogeneous and anisotropic porous media, that makes it possible to solve elliptical problems with accuracy and low computational cost. A scale transfer method is developed that uses the Multiscale Finite Volume Method (MSFVM) to perform a flow based numerical upscaling of absolute permeability. The transmissibility matrix was built in the coarse mesh over the projection and restriction operators obtaining permeability in the coarse scale. This allows to solve only local problems in the coarse mesh volumes and to use pressure multiscale solution in the fine mesh. The permeability field can be obtained by different strategies, and enabling simulations directly on the coarse mesh, controlling the accuracy of the solutions and also with the possibility of updating the permeability field over the recalculated locally conservative multiscale solution.

After more than a year of pandemic, the international medical community has changed the perception of fear to one of respect for SARS-COV-2. This has been the consequence of the integral study of all the dimensions of the disease, from viral recombinant capacity to transmissibility, diagnosis, care and prevention. This document summarizes the main strategic lines of study and approach to the pandemic in Madrid.

To support COVID-19 pandemic planning, we develop a model-inference system to estimate epidemiological properties of new SARS-CoV-2 variants of concern using case and mortality data while accounting for under-ascertainment, disease seasonality, non-pharmaceutical interventions, and mass-vaccination. Applying this system to study three variants of concern, we estimate that B.1.1.7 has a 46.6% (95% CI: 32.3–54.6%) transmissibility increase but nominal immune escape from protection induced by prior wild-type infection; B.1.351 has a 32.4% (95% CI: 14.6–48.0%) transmissibility increase and 61.3% (95% CI: 42.6–85.8%) immune escape; and P.1 has a 43.3% (95% CI: 30.3–65.3%) transmissibility increase and 52.5% (95% CI: 0–75.8%) immune escape. Model simulations indicate that B.1.351 and P.1 could outcompete B.1.1.7 and lead to increased infections. Our findings highlight the importance of preventing the spread of variants of concern, via continued preventive measures, prompt mass-vaccination, continued vaccine efficacy monitoring, and possible updating of vaccine formulations to ensure high efficacy., Quantification of the transmissibility and immune escape properties of SARS-CoV-2 variants is necessary to support pandemic planning. Here, the authors develop a model inference system to estimate these properties using incidence and mortality data for three variants of concern.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is highly contagious and has caused significant medical/socioeconomic impacts. Other than vaccination, effective public health measures, including contact tracing, isolation, and quarantine, is critical for deterring viral transmission, preventing infection progression and resuming normal activities. Viral transmission is affected by many factors, but the viral load and vitality could be among the most important ones. Although in vitro studies have indicated that the amount of virus isolated from infected individuals affects the successful rate of virus isolation, whether the viral load carried at the individual level would determine the transmissibility was unknown. We examined whether the cycle threshold (Ct) value, a measurement of viral load by RT-PCR assay, could differentiate the spreaders from the non-spreaders in a population of college students. Our results indicate that while at the population level the Ct value is lower, suggesting a higher viral load, in the symptomatic spreaders than that in the asymptomatic non-spreaders, there is a significant overlap in the Ct values between the two groups. Thus, Ct value, or the viral load, at the individual level could not predict the transmissibility. Instead, a sensitive method to detect the presence of virus is needed to identify asymptomatic individuals who may carry a low viral load but can still be infectious.

One of the least understood aspects of prion diseases is the structure of infectious prion protein aggregates. Here we report a high-resolution cryo-EM structure of amyloid fibrils formed by human prion protein with Y145Stop mutation that is associated with a familial prion disease. This structural insight allows us not only to explain previous biochemical findings, but also provides direct support for the conformational adaptability model of prion transmissibility barriers.

The aim of this paper is to represents a dynamic behavior of rotor bearing system wirth simply supported beam for three different position disc. rotating machinery such as compressors, turbines, pumps, jet engines, turtobo chargers, etc. are subject to vibrations. rotating machines are operated in very high speed and they are subjected to some unbalance force due to vibration from that machine pass to the foundation of machine.so the analysis of the dynamics parameter of rotor it is important to determine force transmissibility, natural frequency, critical speed and amplitudes of rotor system. Keywords: force transmissibility, vibration, critical speed, rotor bearing system etc.

Determining policies to end the SARS-CoV-2 pandemic will require an understanding of the efficacy and effectiveness (hereafter, efficacy) of vaccines. Beyond the efficacy against severe disease and symptomatic and asymptomatic infection, understanding vaccine efficacy against virus transmission, including efficacy against transmission of different viral variants, will help model epidemic trajectory and determine appropriate control measures. Recent studies have proposed using random virologic testing in individual randomized controlled trials to improve estimation of vaccine efficacy against infection. We propose to further use the viral load measures from these tests to estimate efficacy against transmission. This estimation requires a model of the relationship between viral load and transmissibility and assumptions about the vaccine effect on transmission and the progress of the epidemic. We describe these key assumptions, potential violations of them, and solutions that can be implemented to mitigate these violations. Assessing these assumptions and implementing this random sampling, with viral load measures, will enable better estimation of the crucial measure of vaccine efficacy against transmission.

Aim: To assess the Genetic Variability among the accession/ genotype and its contributing traits. Methodology: A field experiment was conducted using 35 genotypes including 2 checks of rice during the season of kharif, 2017, at the Field Experimental Centre, Department of Genetics and Plant Breeding, SHUATS, Prayagraj, Uttar Pradesh to evaluate genetic variation and heritability of yield and related traits. The experiment was designed with a randomized block design (RBD) with three replications. Analysis of variance revealed significant difference among the genotypes for all traits indicating existence of genetic variability among the accessions. Results: Highest genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were recorded for Spikelet’s per panicle, tillers per hill, panicle per hill and grain filling. High heritability in broad sense was obtained for days to 50% flowering (99.6%), days to maturity (98.7%), test weight (97.9%), harvest index (96.9%) and grain yield per hill (96.6%) which is indicating the high heritable portion of variation. High to medium estimate of heritability in genetic advance were obtained for grain yield (38.51), spikelet’s/ panicle (37.94), panicle/ hill (36.97) were indicating the roles of additive gene action and good scope of selection using their phenotype performance. Interpretation: Considering, all of these characters, spikelet’s per panicle, days to 50% flowering and days to maturity were important yield related traits and could be used for selection in future rice breeding programme.

In the semiconductor manufacturing industry, the dynamic model of a controlled object is usually obtained from a frequency sweeping method before motion control. However, the existing isolators cannot properly isolate the disturbance of the inertial force on the platform base during frequency sweeping (the frequency is between 0 Hz and the natural frequency). In this paper, an adjustable anti-resonance frequency controller for a dual-stage actuation semi-active vibration isolation system (DSA-SAVIS) is proposed. This system has a significant anti-resonance characteristic; that is, the vibration amplitude can drop to nearly zero at a particular frequency, which is called the anti-resonance frequency. The proposed controller is designed to add an adjustable anti-resonance frequency to fully use this unique anti-resonance characteristic. Experimental results show that the closed-loop transmissibility is less than −15 dB from 0 Hz to the initial anti-resonance frequency. Furthermore, it is less than −30 dB around an added anti-resonance frequency which can be adjusted from 0 Hz to the initial anti-resonance frequency by changing the parameters of the proposed controller. With the proposed controller, the disturbance amplitude of the payload decays from 4 to 0.5 mm/s with a reduction of 87.5% for the impulse disturbance applied to the platform base. Simultaneously, the system can adjust the anti-resonance frequency point in real time by tracking the frequency sweeping disturbances, and a good vibration isolation performance is achieved. This indicates that the DSA-SAVIS and the proposed controller can be applied in the guarantee of an ultra-low vibration environment, especially at frequency sweeping in the semiconductor manufacturing industry.

Quasi-zero-stiffness (QZS) vibration isolators can achieve much wider isolation region than equivalent linear isolators. However, most of the existing QZS isolators are designed for a specified direction especially the vertical direction. To broaden the application scope of QZS isolators, this paper presents an in-plane QZS isolator to isolate the vibration occurring in arbitrary direction in the horizontal plane. The proposed isolator is composed of two magnetic rings that are radially magnetized and eight cables that are pre-tensioned. The magnetic interaction offers negative stiffness and the combination of cables offers positive stiffness, which therefore allows the realization of QZS characteristic by proper parameter selection. The vibration in horizontal arbitrary direction can be decomposed into two vibrations in two specified orthogonal directions. Theoretical analysis shows that the proposed isolator possesses superior vibration isolation performance in both the two directions, in terms of bandwidth of isolation region, peak transmissibility and high frequency transmissibility. The superior isolation performance is also demonstrated by experiments.

With an increasing body of evidence that SARS-CoV-2 is an airborne pathogen, droplet character formed during speech, coughs, and sneezes are important. Larger droplets tend to fall faster and are less prone to drive the airborne transmission pathway. Alternatively, small droplets (aerosols) can remain suspended for long time periods. The small size of SARS-CoV-2 enables it to be encapsulated in these aerosols, thereby increasing the pathogen’s ability to be transmitted via airborne paths. Droplet formation during human respiratory events relates to airspeed (speech, cough, sneeze), fluid properties of the saliva/mucus, and the fluid content itself. In this work, we study the fluidic drivers (fluid properties and content) and their influence on factors relating to transmissibility. We explore the relationship between saliva fluid properties and droplet airborne transmission paths. Interestingly, the natural human response appears to potentially work with these drivers to mitigate pathogen transmission. In this work, the saliva is varied using two approaches: (1) modifying the saliva with colloids that increase the viscosity/surface tension, and (2) stimulating the saliva content to increased/decreased levels. Through modern experimental and numerical flow diagnostic methods, the character, content, and exposure to droplets and aerosols are all evaluated. The results indicate that altering the saliva properties can significantly impact the droplet size distribution, the formation of aerosols, the trajectory of the bulk of the droplet plume, and the exposure (or transmissibility) to droplets. High-fidelity numerical methods used and verify that increased droplet size character enhances droplet fallout. In the context of natural saliva response, we find previous studies indicating natural human responses of increased saliva viscosity from stress and reduced saliva content from either stress or illness. These responses both favorably correspond to reduced transmissibility. Such a finding also relates to potential control methods, hence, we compared results to a surgical mask. In general, we find that saliva alteration can produce fewer and larger droplets with less content and aerosols. Such results indicate a novel approach to alter SARS-CoV-2’s transmission path and may act as a way to control the COVID-19 pandemic, as well as influenza and the common cold.

A novel design procedure for tuned mass dampers in isolated structures is presented. The proposed optimization method is specifically developed to control base displacements or to solve the large isolator displacement problem in this type of structures under earthquakes. Therefore, it is based on a displacement transmissibility function, T, a particular case of the general transmissibility concept, which comes from Vibration Isolation. Three contributions are: 1) application of new seismic displacement narrowbandness, 2) simpler relative transmissibility function, and 3) compound design of isolation plus tuned mass damper. A standard isolated model is used to show that the base displacement can be controlled at levels in the proximity of the ground motion ( T ≈ 1), which results in a positive comparison with previous isolation plus tuned mass damper solutions; this is one of the main conclusions and it is based on novelty 3 above; in fact, other solutions in the literature compare their attained displacements with respect to the structure without tuned mass damper. Comparison with isolated results is not, therefore, possible herein, but it is not desirable either; actually, what is possible is a positive and more demanding comparison, which is with respect to the very seismic ground displacement itself. The large isolator displacement problem can be solved or attenuated by properly designing a tuned mass damper subsystem jointly with the isolation one.

Multiple new variants of SARS-CoV-2 have been identified as the COVID-19 pandemic spreads across the globe. However, most epidemic models view the virus as static and unchanging and thus fail to address the consequences of the potential evolution of the virus. Here, we built a competitive susceptible-infected-removed (coSIR) model to simulate the competition between virus strains of differing severities or transmissibility under various virus control policies. The coSIR model predicts that although the virus is extremely unlikely to evolve into a “super virus” that causes an increased fatality rate, virus variants with less severe symptoms can lead to potential new outbreaks and can cost more lives over time. The present model also demonstrates that the protocols restricting the transmission of the virus, such as wearing masks and social distancing, are the most effective strategy in reducing total mortality. A combination of adequate testing and strict quarantine is a powerful alternative to policies such as mandatory stay-at-home orders, which may have an enormous negative impact on the economy. In addition, building Mobile Cabin Hospitals can be effective and efficient in reducing the mortality rate of highly infectious virus strains. Supplementary Information The online version contains supplementary material available at 10.1007/s11071-021-06705-8.

Identifying the fundamental cause of transmissibility of multiple mutation strains and vaccine nullification is difficult in general and is a source of significant concern. The conformational variability of the mutation sites for B.1.617.2 (Δ), B.1.617.1 (κ), B.1.427/429 (e), P.1 (γ), B.1.351 (β), B.1.1.7 (α), S477N, and the wild-type strain has been assessed using a deep neural-network-based prediction program of conformational flexibility or rigidity in proteins (SSSCPreds). We find that although the conformation of G614 is rigid, which is assigned as a left-handed (LH) α-helix-type one, that of D614 is flexible without the hydrogen bonding latch to T859. The rigidity of glycine, which stabilizes the local conformation more effectively than that of aspartic acid with the latch, thereby contributes to the reduction of S1 shedding, high expression, and increase in infectivity. The finding that the sequence flexibility/rigidity map pattern of B.1.1.7 is similar to that of the wild-type strain but is largely different from those of B.1.351 and P.1 correlates with the minor escape ability of B.1.1.7. The increased rigidity of the amino acid sequence YRYRLFR from the SSSCPreds data of B.1.427/429 near the L452R mutation site contributes to the 2-fold increased B.1.427/B.1.429 viral shedding in vivo and the increase in transmissibility relative to wild-type circulating strains in a similar manner to D614G. The concordance and rigidity ratios of multiple mutation strains such as B.1.617.2 against the wild-type one at the receptor-binding domain (RBD) and receptor-binding motif (RBM) regions provide a good indication of the transmissibility and neutralization escape ability except for binding affinity of mutation sites such as N501Y.

A nonlinear vibration isolator with quasi-zero-stiffness (QZS) is designed inspired by the bi-stable Miura-origami tube. The isolator comprises a negative stiffness element with four rods and one horizontal spring, while a vertical linear spring is used to provide positive stiffness. The static characteristics of the negative stiffness element are studied and then the design procedure for the QZS isolation system with a lumped mass is provided. The static displacement is considered as an input parameter to illustrate the high-static-low-dynamicstiffness (HSLDS) property of the isolator. To further display the isolation ability of the present isolator, the dynamic model of the system under base excitation is established with the linear air damping and nonlinear damping caused by rotational joints. The nonlinear terms are then approximated by Taylor series and the averaging method is used to predict the dynamic performance. The present theory is verified by comparing the system’s free and forced responses under different frequencies of base excitation with those calculated by numerical simulation. The displacement transmissibility of the present nonlinear vibration isolator demonstrates the much improved vibration isolation performance as compared to its linear counterpart.

The outbreak of novel coronavirus (COVID-19) has become a global concern that is deteriorating environmental quality and damaging human health. Though some researchers have investigated the linkage between temperature and COVID-19 transmissibility across different geographical locations and over time, yet these studies are scarce. This study aims to bridge this gap using daily temperature and COVID-19 cases (transmissibility) by employing grey incidence analysis (GIA) models (i.e., Deng’s grey incidence analysis (DGIA), the absolute degree GIA (ADGIA), the second synthetic degree GIA (SSDGIA), the conservative (maximin) model) and correlation analysis. Data on temperature are accessed from the NASA database, while the data on COVID-19 cases are collected from the official website of the government of Pakistan. Empirical results reveal the existence of linkages between temperature and COVID-19 in all Pakistani provinces. These linkages vary from a relatively stronger to a relatively weaker linkage. Based on calculated weights, the strength of linkages is ranked across provinces as follows: Gilgit Baltistan (0.715301) > Baluchistan (0.675091) > Khyber Pakhtunkhwa (0.619893) > Punjab (0.619286) > Sindh (0.601736). The disparity in the strength of linkage among provinces is explained by the discrepancy in the intensity of temperature. Besides, the diagrammatic correlation analysis shows that temperature is inversely linked to COVID-19 cases (per million persons) over time, implying that low temperatures are associated with high COVID-19 transmissibility and vice versa. This study is among the first of its kind to consider the linkages between temperature and COVID-19 transmissibility for a tropical climate country (Pakistan) using the advanced GIA models. Research findings provide an up-to-date glimpse of the outbreak and emphasize the need to raise public awareness about the devastating impacts of the COVID-19. The educational syllabus should provide information on the causes, signs, and precautions of the pandemic. Additionally, individuals should practice handwashing, social distancing, personal hygiene, mask-wearing, and the use of hand sanitizers to ensure a secure and supportive atmosphere for preventing and controlling the current pandemic.

COVID researchers are working at breakneck speed to learn about the variant’s transmissibility, severity and ability to evade vaccines. COVID researchers are working at breakneck speed to learn about the variant’s transmissibility, severity and ability to evade vaccines.

The present study proposes a 15-degrees of freedom multibody model of semi-supine humans to estimate the injury risk to a space capsule occupant during landing. The model consists of five body segm...

From early in the COVID-19 pandemic, economists have stressed the importance of individuals endogenously changing their behavior to reduce their risk of infection. This paper quantifies time variation in the endogenous behavioral response of economic activity to the prevalence of the virus using an estimated behavioral SIR model with time-varying parameters. We find significant variation in both the relationship between economic activity and viral prevalence and the relationship between transmissibility and economic activity. This variation reflects adaptation to the pandemic and has implications both for specification of behavioral SIR models and for the next stage of the pandemic.

The SARS-CoV-2 lineage B.1.1.7, designated variant of concern (VOC) 202012/01 by Public Health England1, was first identified in the UK in late summer to early autumn 20202. Whole-genome SARS-CoV-2 sequence data collected from community-based diagnostic testing for COVID-19 show an extremely rapid expansion of the B.1.1.7 lineage during autumn 2020, suggesting that it has a selective advantage. Here we show that changes in VOC frequency inferred from genetic data correspond closely to changes inferred by S gene target failures (SGTF) in community-based diagnostic PCR testing. Analysis of trends in SGTF and non-SGTF case numbers in local areas across England shows that B.1.1.7 has higher transmissibility than non-VOC lineages, even if it has a different latent period or generation time. The SGTF data indicate a transient shift in the age composition of reported cases, with cases of B.1.1.7 including a larger share of under 20-year-olds than non-VOC cases. We estimated time-varying reproduction numbers for B.1.1.7 and co-circulating lineages using SGTF and genomic data. The best-supported models did not indicate a substantial difference in VOC transmissibility among different age groups, but all analyses agreed that B.1.1.7 has a substantial transmission advantage over other lineages, with a 50% to 100% higher reproduction number.

It is important to estimate transmissibility of influenza virus dur- ing its growing phase for understanding the propagation of the virus. The estimation procedures of the transmissibility are usually based on the data generated in flu seasons. The data-generating process of the outbreak of influenza has many features. The data is generated by not only a biological process but also control measures such as flu vaccination. The estimation is discussed by considering the aspects of the data-generating process and using the model to capture the essential characteristics of flu transmission during the growing phase of a flu season.

We recently reported that most of the onion yellow dwarf virus (OYDV) isolates detected from garlic in Hokkaido, Japan have a short HC-Pro. Because HC-Pro has been found to be necessary for aphid transmission, OYDV with a short HC-Pro (OYDV-S) conceivably may have lost aphid transmissibility. We here confirmed that OYDV-S was transmitted by aphids only when coinfecting the host with another potyvirus, leek yellow stripe virus (LYSV); OYDV with an intact HC-Pro was transmitted by aphids without LYSV. We presume that LYSV HC-Pro works in trans as a platform that interlinks both LYSV and OYDV-S with the aphid stylet.

Population scale sweeps of viral pathogens, such as SARS-CoV-2, require high intensity testing for effective management. Here, we describe “Systematic Parallel Analysis of RNA coupled to Sequencing for Covid-19 screening” (C19-SPAR-Seq), a multiplexed, scalable, readily automated platform for SARS-CoV-2 detection that is capable of analyzing tens of thousands of patient samples in a single run. To address strict requirements for control of assay parameters and output demanded by clinical diagnostics, we employ a control-based Precision-Recall and Receiver Operator Characteristics (coPR) analysis to assign run-specific quality control metrics. C19-SPAR-Seq coupled to coPR on a trial cohort of several hundred patients performs with a specificity of 100% and sensitivity of 91% on samples with low viral loads, and a sensitivity of >95% on high viral loads associated with disease onset and peak transmissibility. This study establishes the feasibility of employing C19-SPAR-Seq for the large-scale monitoring of SARS-CoV-2 and other pathogens., Wide-spread outbreaks of pathogens require high intensity testing to manage. Here, the authors present C19-SPAR-Seq, a scalable and automated platform to analyse tens of thousands of SARS-CoV-2 patient samples in a single run.

Quasi-zero stiffness (QZS) isolators can achieve superior performance in vibration isolation; however, this superiority is often effective only for an excitation with the small excitation amplitude due to the narrow QZS region around the static equilibrium positions. A QZS isolator with multi-pairs of oblique springs can increase the QZS region, but its isolation frequency band is still narrow owing to the large static deflection. This article presents an improved isolator with two pairs of oblique springs by setting an initial position to be located between the supporting points of the upper pair of oblique springs and the equilibrium position so that the static deflection is significantly decreased, and thus, the isolation frequency band can be considerably increased. New formulations of stiffness and displacement transmissibility are derived for the improved QZS isolator. A prototype is designed, fabricated and tested to verify benefits of the present QZS isolator for vibration mitigation. Numerical results of the present isolator predicted by experiment and theory are compared with those of the corresponding linear isolator and previous QZS isolator to show advantages of the innovated design for vibration isolation.

Aim: Because the highly pathogenic SARS-CoV-2 is newly introduced to humans, we aimed to understand the unique features of its genome and proteins, crucial for high transmissibility and disease severity. Materials & methods: The available genome and protein sequences of SARS-CoV-2 with known human and nonhuman CoV were analyzed using multiple sequence alignment programs. Results: Our analysis revealed some unique mutations in SARS-CoV-2 spike, ORF1a/b, ORF3a/3b and ORF8. The most interesting ones were in the spike angiotensin-converting enzyme 2 receptor binding-motif and generation of a furin-like cleavage site as well as deletions of ORF3a ‘diacidic motif’ and the entire ORF3b. Conclusion: Our data suggest that SARS-CoV-2 has diverged from SARS-CoV-1 but is most close to bat-SL-CoV. Unique mutations in spike and ORF3a/b proteins strongly endorse its adaptive evolution, enhanced infectivity and severe pathogenesis in humans.

Highlights • The rapid antigen test (RAT) and RT-qPCR positive concordance rate is low in COVID-19. • In the early stages of disease, positive and negative concordance rates are acceptable. • Factors related to disagreement between RAT and RT-qPCR results were investigated. • The predictive ability of RAT for disease transmissibility was examined. • RAT and RT-qPCR results were highly consistent; results can infer transmissibility., Objectives Rapid antigen testing (RAT) for coronavirus disease 2019 (COVID-19) has lower sensitivity but high accuracy during the early stage when compared to reverse transcription quantitative polymerase chain reaction (RT-qPCR). The aim of this study was to investigate the concordance between RAT and RT-qPCR results, and their prediction of disease transmission. Methods This single-center retrospective observational study of inpatients with COVID-19 was conducted from March 6 to June 14, 2020. Nasopharyngeal swabs were used to perform RAT and RT-qPCR. The primary endpoint was concordance between RAT and RT-qPCR results. The secondary endpoints were the factors causing disagreement in the results and the estimated transmissibility in RT-qPCR-positive patients with mild symptoms. Results Overall, 229 samples in viral transport medium (VTM) were obtained from 105 patients. The positive and negative concordance rates for VTM were 41% vs 99% (κ = 0.37) and 72% vs 100% (κ = 0.50) for samples collected on disease days 2–9. An increased body temperature (odds ratio 0.54) and absence of drugs with potential antiviral effect (odds ratio 0.48) yielded conflicting results. RAT was associated with the ability to end isolation (OR 0.11, 95% confidence interval 0.20–0.61). Conclusions RAT and RT-qPCR results were highly consistent for samples collected at the appropriate time and could be useful for inferring the possibility of transmissibility.

Human respiratory virus infections lead to a spectrum of respiratory symptoms and disease severity, contributing to substantial morbidity, mortality and economic losses worldwide, as seen in the COVID-19 pandemic. Belonging to diverse families, respiratory viruses differ in how easy they spread (transmissibility) and the mechanism (modes) of transmission. Transmissibility as estimated by the basic reproduction number (R0) or secondary attack rate is heterogeneous for the same virus. Respiratory viruses can be transmitted via four major modes of transmission: direct (physical) contact, indirect contact (fomite), (large) droplets and (fine) aerosols. We know little about the relative contribution of each mode to the transmission of a particular virus in different settings, and how its variation affects transmissibility and transmission dynamics. Discussion on the particle size threshold between droplets and aerosols and the importance of aerosol transmission for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza virus is ongoing. Mechanistic evidence supports the efficacies of non-pharmaceutical interventions with regard to virus reduction; however, more data are needed on their effectiveness in reducing transmission. Understanding the relative contribution of different modes to transmission is crucial to inform the effectiveness of non-pharmaceutical interventions in the population. Intervening against multiple modes of transmission should be more effective than acting on a single mode., In this Review, Leung provides an overview of the transmissibility and modes of transmission of respiratory viruses, the viral, host and environmental determinants of transmission, and common non-pharmaceutical interventions for mitigating respiratory virus transmission. She also discusses the recent controversies over aerosol transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19.

The Future of SARS-CoV-2 Vaccination Given the parade of SARS-CoV-2 variants, their increasing transmissibility, and concern about antigenic changes affecting vaccine protection, we need long-term ...

The extremely high nature of transmissibility and severity of infection due to the novel Corona virus is a serious threat to mankind. This letter delivers a cau-tion for forensic DNA experts in the era of COVID-19 infection from the Indian perspective. Samples are routinely transported to laboratories without any spe-cific guidelines. Therefore, this is high time to formu-late clear guidelines for the handling of biological ma-terial, from receiving to processing in the laboratory during such a pandemic. © 2021. AJFSFM.

Domestic cats, an important companion animal, can be infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). This has aroused concern regarding the ability of domestic cats to spread the virus that causes coronavirus disease 2019. We systematically demonstrated the pathogenesis and transmissibility of SARS-CoV-2 in cats. Serial passaging of the virus between cats dramatically attenuated the viral transmissibility, likely owing to variations of the amino acids in the receptor-binding domain sites of angiotensin-converting enzyme 2 between humans and cats. These findings provide insight into the transmissibility of SARS-CoV-2 in cats and information for protecting the health of humans and cats.

A vibration isolator system with nonlinear stiffness is designed and tested to solve problems on marine noise measuring equipment which are caused by underwater flow. The low frequency response characteristics of the vibration isolation system are evaluated from static function and dynamic simulation with Harmonic Balance Method. The theoretical analysis results show that the total stiffness value of the isolator system will be kept in 0 point around when parallel springs stay in equilibrium position. In order to assess the practical efficiency of Quasi-Zero-Stiffness (QZS) isolator, a vibration response test is carried out. By comparing the acceleration signals at 5 Hz and 100 Hz between linear and nonlinear system in time domain and frequency domain, the transmissibility curves are obtained. The experimental results demonstrate that the isolation system expands the frequency range of operation effectively by decreasing the natural frequency of the QZS vibration isolator. In addition, the QZS isolation system decreases the transmissibility of vibration by reducing the amplitude of output signals. The QZS isolator has more outstanding performance in contrast to linear spring in ultralow frequency isolation field.

This paper resolves analytically a mathematical model that reproduces the transmission of Covid-19 in three interactive populations, i.e. from the initial source of contagion associated with the bat population, subsequently transmitted to unknown host (usually associate with pangolins). The host were sent and distributed to Seafood Market in Wuhan (defined reservoir), and finally infected to the human population. The model is based on a system of ten differential equations reproducing all the possible infection scenarios among all of them, that is: (1) there is no infection in any of the three populations, (2) only the population of bats is infected, (3) only the pangolins, (4) only the human people. Later, combinations between them, this is: (5) both the bat and pangolin populations, (6) bats and humans, (7) pangolins and humans, and finally, (8) all the previous populations. In each scenario, I deduced the critical points as well as the eigenvalues that indicate the equilibrium conditions. Finally, it is demonstrated the validity of the model with the data corresponding to the second wave of infections in Australia

This paper proposes various stages of the hepatitis B virus (HBV) besides its transmissibility and nonlinear incidence rate to develop an epidemic model. The authors plan the model, and then prove some basic results for the well-posedness in term of boundedness and positivity. Moreover, the authors find the threshold parameter R0, called the basic/effective reproductive number and carry out local sensitive analysis. Furthermore, the authors examine stability and hence condition for stability in terms of R0. By using sensitivity analysis, the authors formulate a control problem in order to eradicate HBV from the population and proved that the control problem actually exists. The complete characterization of the optimum system was achieved by using the 4th-order Runge-Kutta procedure.

In this study, a novel criterion known as the comprehensive transmissibility is proposed to estimate the isolation performance of nonlinear isolation systems under complex loading excitations. A combined quasi-zero-stiffness (QZS) isolator is enumerated, and the comprehensive performance of other common isolator systems and the existing QZS system is analyzed. Based on the normalized differential equations of the isolation system, the isolation performances of different isolation systems are studied by using the comprehensive transmissibility criterion, showing that the combined QZS isolator has better isolation performance than others. In addition, the output frequency response function (OFRF) representation of the comprehensive transmissibility is derived, and the optimal design of the QZS isolation system is developed by using the OFRF. The simulation results demonstrate that the design can meet the requirements of the vibration isolator with both the force and displacement excitations and is promised to be applied to the design of nonlinear isolation systems in engineering practice. To solve the issue of the analysis and design of nonlinear vibration isolation systems under multi-excitation, a new criterion known as comprehensive transmissibility is proposed. Based on the comprehensive transmissibility, the isolation performance of the combined vibration isolation system is analyzed, and the output frequency response function (OFRF) method is applied to conduct the design of the isolation system.