scholarly journals Estimating the Changing Infection Rate of COVID-19 Using Bayesian Models of Mobility

2020 ◽  
Author(s):  
Luyang Liu ◽  
Sharad Vikram ◽  
Junpeng Lao ◽  
Xue Ben ◽  
Alexander D'Amour ◽  
...  
Keyword(s):  
Growth Rate ◽  
Infection Rate ◽  
Compartmental Model ◽  
Realistic Model ◽  
Local Growth ◽  
Mobility Data ◽  
Latent Time ◽  
Erlang Distributions ◽  
And Control ◽  
Case Data

In order to prepare for and control the continued spread of the COVID-19 pandemic while minimizing its economic impact, the world needs to be able to estimate and predict COVID-19's spread. Unfortunately, we cannot directly observe the prevalence or growth rate of COVID-19; these must be inferred using some kind of model. We propose a hierarchical Bayesian extension to the classic susceptible-exposed-infected-removed (SEIR) compartmental model that adds compartments to account for isolation and death and allows the infection rate to vary as a function of both mobility data collected from mobile phones and a latent time-varying factor that accounts for changes in behavior not captured by mobility data. Since confirmed-case data is unreliable, we infer the model's parameters conditioned on deaths data. We replace the exponential-waiting-time assumption of classic compartmental models with Erlang distributions, which allows for a more realistic model of the long lag between exposure and death. The mobility data gives us a leading indicator that can quickly detect changes in the pandemic's local growth rate and forecast changes in death rates weeks ahead of time. This is an analysis of observational data, so any causal interpretations of the model's inferences should be treated as suggestive at best; nonetheless, the model's inferred relationship between different kinds of trips and the infection rate do suggest some possible hypotheses about what kinds of activities might contribute most to COVID-19's spread.

scholarly journals Forecasting the Spread of COVID-19 under Different Reopening Strategies

2020 ◽  
Author(s):  
Meng Liu ◽  
Raphael Thomadsen ◽  
Song Yao
Keyword(s):  
United States ◽  
Growth Rate ◽  
Population Density ◽  
The United States ◽  
Sir Model ◽  
Social Distancing ◽  
Mobility Data ◽  
The Social ◽  
The Us ◽  
Case Data

ABSTRACTWe combine COVID-19 case data with demographic and mobility data to estimate a modified susceptible-infected-recovered (SIR) model for the spread of this disease in the United States. We find that the incidence of infectious COVID-19 individuals has a concave effect on contagion, as would be expected if people have inter-related social networks. We also demonstrate that social distancing and population density have large effects on the rate of contagion. The social distancing in late March and April substantially reduced the number of COVID-19 cases. However, the concave contagion pattern means that when social distancing measures are lifted, the growth rate is considerable but will not be exponential as predicted by standard SIR models. Furthermore, counties with the lowest population density could likely avoid high levels of contagion even with no social distancing. We forecast rates of new cases for COVID-19 under different social distancing norms and find that if social distancing is eliminated there will be a massive increase in the cases of COVID-19, about double what would occur if the US only restored to 50% of the way to normalcy.

scholarly journals Mining Google and Apple mobility data: temporal anatomy for COVID-19 social distancing

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Corentin Cot ◽  
Giacomo Cacciapaglia ◽  
Francesco Sannino
Keyword(s):  
Infection Rate ◽  
The United States ◽  
Strong Decrease ◽  
Social Distancing ◽  
Mobility Data ◽  
Actual Measure ◽  
The Us ◽  
The Impact ◽  
Political Decisions ◽  
Mobility Reduction

AbstractWe employ the Google and Apple mobility data to identify, quantify and classify different degrees of social distancing and characterise their imprint on the first wave of the COVID-19 pandemic in Europe and in the United States. We identify the period of enacted social distancing via Google and Apple data, independently from the political decisions. Our analysis allows us to classify different shades of social distancing measures for the first wave of the pandemic. We observe a strong decrease in the infection rate occurring two to five weeks after the onset of mobility reduction. A universal time scale emerges, after which social distancing shows its impact. We further provide an actual measure of the impact of social distancing for each region, showing that the effect amounts to a reduction by 20–40% in the infection rate in Europe and 30–70% in the US.

Hong Kong’s response to COVID-19: a glance to the control measures and their enforcement

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ka Ki Lawrence Ho ◽  
Ying-Tung Chan
Keyword(s):  
Hong Kong ◽  
Infection Rate ◽  
Government Policy ◽  
Design Methodology ◽  
Control Measures ◽  
Content Type ◽  
The Government ◽  
And Control ◽  
Viral Outbreak

Purpose This study aims to examine Hong Kong’s responses to COVID-19, arguing that Hong Kong’s relatively low infection rate is due to self-discipline of citizens together with the enforcement measures introduced by the government. Design/methodology/approach This study reviewed the government policy announcements and the prevailing scholarly analyses on Hong Kong society during COVID-19. Findings It starts by examining the partial lockdown and control measures since mid-January, and the roles of different government units in enforcement were examined and assessed. Suppression of viral outbreak in Hong Kong should primarily be attributed to the appropriate lockdown and quarantine actions of the government. Originality/value However, outperformance of the frontline professionals and the highly aware, self-disciplined and mutually aided citizens in the community are also the key to the “interim success” by June 2020 in the highly accessible and densely populated city.

The effect of antibiotic dietary supplements on the carcass measurements and dressing percentage of bacon pigs

1955 ◽  
Vol 46 (2) ◽  
pp. 173-179 ◽  
Author(s):  
G. Harrington ◽  
J. H. Taylor
Keyword(s):  
Growth Rate ◽  
Vitamin B12 ◽  
Dietary Supplements ◽  
Vegetable Protein ◽  
Animal Protein ◽  
Feeding Trials ◽  
The Mean ◽  
Dressing Percentage ◽  
And Control

1. Certain carcass measurements (length, shoulder and mid-back fats, belly thickness and dressing percentage) made on a total of 402 bacon pigs from four antibiotic feeding trials have been analysed.2. The length of the carcasses showed more variation between pens treated with various doses of penicillin than between control pens or pens treated with aureomycin. This greater variation in length was related to the greater variation in growth rate between the penicillin treatments. No differences in the mean lengths of control, penicillin and aureomycin treatments were found.3. Back fat measurements and belly thickness showed no differences between aureomycin, penicillin and control treatments in overall tests.4. Aureomycin consistently gave higher dressing percentages than penicillin. Animal protein also gave higher dressing percentages than vegetable protein, but no effect of vitamin B12 on this quantity was found.

scholarly journals Growth of Microcystis strains isolated from environments with the presence and absence of submerged macrophytes in coexistence with Ceratophyllum demersum

2021 ◽  
Vol 43 ◽  
pp. e57734
Author(s):  
Rafael Henrique de Moura-Falcão ◽  
Ariadne do Nascimento Moura ◽  
Cihelio Alves Amorim
Keyword(s):  
Growth Rate ◽  
Submerged Macrophytes ◽  
T Test ◽  
Submerged Macrophyte ◽  
Cyanobacterial Blooms ◽  
Growth Delay ◽  
Ceratophyllum Demersum ◽  
Significant Difference ◽  
Presence And Absence ◽  
And Control

Cyanobacterial blooms can cause severe ecological and health problems in drinking water reservoirs. To alleviate this problem, allelopathically active submerged macrophytes can be used to reduce cyanobacterial growth. Accordingly, this study aimed to evaluate the sensitivity of strains of the Microcystis aeruginosa complex isolated from reservoirs with the presence and absence of submerged macrophytes to the allelochemicals of Ceratophyllum demersum. A coexistence experiment was carried out between the submerged macrophyte C. demersum and four Microcystis strains, with two treatments for each strain, one in coexistence with the submerged macrophyte (7 g L-1) and control (in the absence of the macrophyte). Two strains of M. aeruginosa (BMIUFRPE-06 and BMIUFRPE-07) and two of M. panniformis (BMIUFRPE-08 and BMIUFRPE-09) were used, which were isolated from Cajueiro (with submerged macrophytes) and Tapacurá (without submerged macrophytes) reservoirs, respectively. The biomass of Microcystis strains from the reservoir without macrophytes (BMIUFRPE-08 and BMIUFRPE-09) was significantly inhibited in 96% (T-test: p < 0.01) and 74% (T-test: p< 0.05), when compared to the control, respectively, with lower values of growth rates (ANOVA: p < 0.05). The strains isolated from the reservoir with macrophytes (BMIUFRPE-06 and BMIUFRPE-07) showed a growth delay (biomass reductions of 44 and 58%, respectively) in the coexistence treatment but without significant difference from the control on the sixth day of the experiment (biomass - T-test: p > 0.05; growth rate - ANOVA: p > 0.05). These results suggest that strains isolated from environments with submerged macrophytes are less sensitive to allelochemicals of these plants, as these strains may be adapted to the coexistence with submerged macrophytes.

scholarly journals Growth rate of african catfish (Clarias gariepinus) and plankton diversity in ponds under organic and inorganic fertilization

2021 ◽  
Vol 21 (02) ◽  
pp. 17545-17559
Author(s):  
PA Otieno ◽  
◽  
DO Owiti ◽  
PO Onyango ◽  
◽  
...  
Keyword(s):  
Growth Rate ◽  
Clarias Gariepinus ◽  
Chicken Manure ◽  
Average Weight ◽  
African Catfish ◽  
Phytoplankton Species ◽  
Inorganic Fertilizers ◽  
Average Growth ◽  
Plankton Diversity ◽  
And Control

Aquaculture offers the opportunity for safeguarding local and global food security in the face of declining capture fisheries. However, the form of aquaculture that is commonly practiced in Kenya is characterized by the use of agrochemicals such as fertilizers that negatively impact biodiversity especially when effluents from fish ponds drain into water bodies. This study aimed to determine differences in the growth rate of Clarias gariepinus, an important aquaculture fish in Kenya, to assess plankton diversity, and to identify phytoplankton species associated with pollution under organic and inorganic fertilization regimens using chicken manure, Diammonium phosphate, and urea, respectively. Average growth rate calculated per day was higher in the organically-fertilized ponds at 0.06 cm/day, followed by inorganically-fertilized ponds at 0.05cm/day and then, the control at 0.04 cm/day. Average weight gain was higher in organically-fertilized ponds at 0.08 g/day followed by ponds fertilized with inorganic fertilizer at 0.07 g/day and the control, at 0.06g/day. There were significant differences in growth rate across fertilization regimens (length: F2, 264= 24.06, p = 0.0399; weight: F2, 264 = 20.89, p = 0. 0457). Specifically, although differences in growth rate of fish in organically and inorganically fertilized ponds were not significant, fish in fertilized ponds were on average, longer and weighed more than those in the control pond. Jaccard’s similarity index for phytoplankton was highest (0.38) between organically-fertilized ponds and control but lowest (0.25) between inorganically-fertilized ponds and control. Use of chicken manure produced the highest diversity of zooplankton (Shannon-Weiner’s H in organically-fertilized pond = 1.886; inorganic = 1.044, and control = 0.935). The use of DAP and urea produced the highest proportion of phytoplankton species associated with pollution. These results do not support the commonly reported notion that ponds fertilized using inorganic fertilizers are more productive. Findings suggest that the use of inorganic fertilizers may threaten biodiversity in aquatic ecosystems through the production of toxic algae.

scholarly journals Studies in the geotropism of the pteridophyta V—Some effects of temperature on growth and geotropism in Asplenium bulbiferium

1935 ◽  
Vol 116 (800) ◽  
pp. 479-493 ◽  
Keyword(s):  
Growth Rate ◽  
Effect Of Temperature ◽  
Horizontal Position ◽  
Present Position ◽  
Minimum Period ◽  
Plant Life ◽  
Latent Time ◽  
Presentation Time ◽  
Effects Of Temperature ◽  
The Given

Although temperature and gravity both influence plant life, and although both factors have been studied for many decades, there is surprisingly little literature decades, there is surprisingly little literature dealing with the relation between the two; and none, so far as I can discover, on the effect in any Pteridophyte. Navez (1929) who criticized the work of some investigators on the effect of temperature on the geotropism of a few seedlings, sums up the present position in his remark that the conclusions of workers are very different and often in opposition. The present paper gives the results of 1100 experiments carried out mainly between the years 1922 and 1927, and though it is realized that much remains to be done on the question, it is believed that the results which have been obtained are of some value. For general methods, reference may be made to previous “Studies” in this series. Geotropic sensitivity, as measured by presentation time at different stages in development of the frond, was fully worked out by Waight (1923) for 20°C, and is adopted here as a standard of reference. The growth rate recorded in the tables is that for the particular frond under investigation, or is the average of the fronds examined during the day of the experiment. Nearly all the experiments included in the tables were conducted during the months of April-October, as I have since been able to show that there is an annual rhythm in geotropic irritability. A decrease in sensitivity occurs in winter, and hence experiments performed in November-March are not strictly comparable with those carried out in the summer. The following abbreviations are used:- P.S. = period of stimulation. P.T. = presentation time, i. e ., the minimum period of stimulation in a horizontal position, which, under the given conditions, will cause a movement of approximately 5° in about 80% of the fronds. L.T. = latent time (Prankerd, 1925) in hours. N = “normal time,” i. e ., the P.T. For different stages of the frond at 20°C (see Waight, 1923).

scholarly journals Prediction of the Peak, Effect of Intervention, and Total Infected by COVID-19 in India

2020 ◽  
pp. 1-11
Author(s):  
Parth Vipul Shah
Keyword(s):  
Health Care ◽  
Infection Rate ◽  
Compartmental Model ◽  
Total Population ◽  
Reproduction Number ◽  
Least Square Method ◽  
Peak Effect ◽  
Least Square ◽  
Intervention Period ◽  
Care Capacity

ABSTRACT Objectives: We study the effect of the coronavirus disease 2019 (COVID-19) in India and model the epidemic to guide those involved in formulating policy and building health-care capacity. Methods: This effect is studied using the Susceptible-Exposed-Infected-Recovered (SEIR) compartmental model. We estimate the infection rate using a least square method with Poisson noise and calculate the reproduction number. Results: The infection rate is estimated to be 0.270 and the reproduction number to be 2.70. The approximate peak of the epidemic will be August 9, 2020. A 25% drop in infection rate will delay the peak by 11 d for a 1-mo intervention period. The total infected individuals in India will be 9% of the total population. Conclusions: The predictions are sensitive to changes in the behavior of people and their practice of social distancing.

scholarly journals Enhancement of clover growth by inoculation of P-solubilizing fungi and arbuscular mycorrhizal fungi

2010 ◽  
Vol 82 (3) ◽  
pp. 771-777 ◽  
Author(s):  
Edson L. Souchie ◽  
Rosario Azcón ◽  
Jose M. Barea ◽  
Eliane M.R. Silva ◽  
Orivaldo J. Saggin-Júnior
Keyword(s):  
Growth Rate ◽  
Aspergillus Niger ◽  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Trifolium Pratense ◽  
Arbuscular Mycorrhizal ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Environment Chamber ◽  
And Control

This study evaluated the synergism between several P-solubilizing fungi isolates and arbuscular mycorrhizal fungi to improve clover ( Trifolium pratense) growth in the presence of Araxá apatite. Clover was sown directly in plastic pots with 300g of sterilized washed sand, vermiculite and sepiolite 1:1:1 (v:v:v) as substrate, and grown in a controlled environment chamber. The substrate was fertilized with 3 g L-1 of Araxá apatite. A completely randomized design, in 8×2 factorial scheme (eight P-solubilizing fungi treatments with or without arbuscular mycorrhizal fungi)and four replicates were used. The P-solubilizing fungi treatments consisted of five Brazilian P-solubilizing fungi isolates (PSF 7, 9, 20, 21 and 22), two Spanish isolates ( Aspergillus niger and the yeast Yarowia lipolytica) and control (non-inoculated treatment). The greatest clover growth rate was recorded when Aspergillus niger and PSF 21 were co-inoculated with arbuscular mycorrhizal fungi. Aspergillus niger, PSF 7 and PSF 21 were the most effective isolates on increasing clover growth in the presence of arbuscular mycorrhizal fungi. Greater mycorrhizal colonization resulted in greater clover growth rate in most PSF treatments. PSF 7 was the best isolate to improve the establishment of mycorrhizal and rhizobia symbiosis.

Integrated Model Of Industrial Robot For Control Applications

1992 ◽  
pp. 27-41
Author(s):  
Johari Halim Shah Osman
Keyword(s):  
Robot Manipulator ◽  
Industrial Robot ◽  
Realistic Model ◽  
Integrated Model ◽  
Control Synthesis ◽  
Real Situation ◽  
Highly Nonlinear ◽  
Gear Trains ◽  
And Control ◽  
Space Description

This paper deals with the development of an intergrated mathematical model of a robot manipulator. The model of the system comprises the mechanical part of the robot as well as the actuators and the gear trains. Two different approaches of deriving the integrated model are presented which results in two different forms of the integrated dynamic model of the robot manipulator in state space description. Both types of the integrated model are highly nonlinear, time varying, and represent a more realistic model of the robotic system. The integrated model and the approach are useful and suitable for dynamic analysis and control synthesis purposes, and will provide a more efficient approach to the real situation.

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