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1.
Bull Math Biol ; 85(6): 54, 2023 05 11.
Article in English | MEDLINE | ID: covidwho-2318476

ABSTRACT

Metapopulation models have been a popular tool for the study of epidemic spread over a network of highly populated nodes (cities, provinces, countries) and have been extensively used in the context of the ongoing COVID-19 pandemic. In the present work, we revisit such a model, bearing a particular case example in mind, namely that of the region of Andalusia in Spain during the period of the summer-fall of 2020 (i.e., between the first and second pandemic waves). Our aim is to consider the possibility of incorporation of mobility across the province nodes focusing on mobile-phone time-dependent data, but also discussing the comparison for our case example with a gravity model, as well as with the dynamics in the absence of mobility. Our main finding is that mobility is key toward a quantitative understanding of the emergence of the second wave of the pandemic and that the most accurate way to capture it involves dynamic (rather than static) inclusion of time-dependent mobility matrices based on cell-phone data. Alternatives bearing no mobility are unable to capture the trends revealed by the data in the context of the metapopulation model considered herein.


Subject(s)
COVID-19 , Humans , COVID-19/epidemiology , Pandemics , Models, Biological , Mathematical Concepts , Time
2.
Phys Rev E ; 107(4-1): 044202, 2023 Apr.
Article in English | MEDLINE | ID: covidwho-2299757

ABSTRACT

In this paper, an approach to the disease transmission dynamic of a coronavirus pandemic is presented. Compared to models commonly known from the literature, new classes that describe this dynamic to our model were added, which are a class representing costs of the pandemic and a class of the individuals being vaccinated but without antibodies. Parameters which at most of them depend on time were used. Sufficient conditions for a dual ɛ-closed-loop Nash equilibrium in the form of the verification theorem are formulated. A numerical algorithm and numerical example are constructed.


Subject(s)
Algorithms , Pandemics , Humans , Time
3.
Int J Psychoanal ; 103(5): 744-760, 2022 10.
Article in English | MEDLINE | ID: covidwho-2249972

ABSTRACT

Since the Covid pandemic required the implementation of restrictions, my patients have been concerned with their experience of time, which seemed distorted by the state of emergency impacting on our lives, and often elicited the feeling of inhabiting a dystopian world. There appear existential demands for subjective meaning, especially when the fear of death is so intense it appears uncontainable. The state of uncertainty impacts upon the sense of the future, and hence on desire and hope: affect states that emerge primarily from the internal world. Within the framework of Western thought, time is linear (Cronos), cyclical and recursive (Aion) or fugitively punctual (Kairos). These figures of time implicate the interaction between the internal and external world within a first-person account. The paper focuses on Kairos - that critical moment where the subject's sense of reality through attention serves self-protective functions and leads to action. Kairos is also the temporality of trauma. Vignettes from two patients, of different ages and in different phases of analyses, illustrate the subjective vicissitudes of Kairos, depending on the state of the self, ego, and biographical inscriptions in a wider human chronology. Freud's equation: perception=attention=time captures the psychic work and significance of the temporality of Kairos.


Subject(s)
COVID-19 , Pandemics , Humans , Phobic Disorders , Time
5.
PLoS Comput Biol ; 18(10): e1010602, 2022 10.
Article in English | MEDLINE | ID: covidwho-2054252

ABSTRACT

We analyze an ensemble of n-sub-epidemic modeling for forecasting the trajectory of epidemics and pandemics. These ensemble modeling approaches, and models that integrate sub-epidemics to capture complex temporal dynamics, have demonstrated powerful forecasting capability. This modeling framework can characterize complex epidemic patterns, including plateaus, epidemic resurgences, and epidemic waves characterized by multiple peaks of different sizes. We systematically assess their calibration and short-term forecasting performance in short-term forecasts for the COVID-19 pandemic in the USA from late April 2020 to late February 2022. We compare their performance with two commonly used statistical ARIMA models. The best fit sub-epidemic model and three ensemble models constructed using the top-ranking sub-epidemic models consistently outperformed the ARIMA models in terms of the weighted interval score (WIS) and the coverage of the 95% prediction interval across the 10-, 20-, and 30-day short-term forecasts. In our 30-day forecasts, the average WIS ranged from 377.6 to 421.3 for the sub-epidemic models, whereas it ranged from 439.29 to 767.05 for the ARIMA models. Across 98 short-term forecasts, the ensemble model incorporating the top four ranking sub-epidemic models (Ensemble(4)) outperformed the (log) ARIMA model 66.3% of the time, and the ARIMA model, 69.4% of the time in 30-day ahead forecasts in terms of the WIS. Ensemble(4) consistently yielded the best performance in terms of the metrics that account for the uncertainty of the predictions. This framework can be readily applied to investigate the spread of epidemics and pandemics beyond COVID-19, as well as other dynamic growth processes found in nature and society that would benefit from short-term predictions.


Subject(s)
COVID-19 , Humans , United States/epidemiology , COVID-19/epidemiology , Pandemics , Forecasting , Models, Statistical , Time
6.
Philos Trans A Math Phys Eng Sci ; 380(2233): 20210308, 2022 Oct 03.
Article in English | MEDLINE | ID: covidwho-1992465

ABSTRACT

During infectious disease outbreaks, inference of summary statistics characterizing transmission is essential for planning interventions. An important metric is the time-dependent reproduction number (Rt), which represents the expected number of secondary cases generated by each infected individual over the course of their infectious period. The value of Rt varies during an outbreak due to factors such as varying population immunity and changes to interventions, including those that affect individuals' contact networks. While it is possible to estimate a single population-wide Rt, this may belie differences in transmission between subgroups within the population. Here, we explore the effects of this heterogeneity on Rt estimates. Specifically, we consider two groups of infected hosts: those infected outside the local population (imported cases), and those infected locally (local cases). We use a Bayesian approach to estimate Rt, made available for others to use via an online tool, that accounts for differences in the onwards transmission risk from individuals in these groups. Using COVID-19 data from different regions worldwide, we show that different assumptions about the relative transmission risk between imported and local cases affect Rt estimates significantly, with implications for interventions. This highlights the need to collect data during outbreaks describing heterogeneities in transmission between different infected hosts, and to account for these heterogeneities in methods used to estimate Rt. This article is part of the theme issue 'Technical challenges of modelling real-life epidemics and examples of overcoming these'.


Subject(s)
COVID-19 , Bayes Theorem , COVID-19/epidemiology , Disease Outbreaks , Humans , Reproduction , Time
7.
Indian J Med Res ; 152(1 & 2): 121-123, 2020.
Article in English | MEDLINE | ID: covidwho-1383945
10.
Ann Thorac Surg ; 110(6): 2107-2108, 2020 12.
Article in English | MEDLINE | ID: covidwho-1382221
11.
Med Decis Making ; 42(6): 765-775, 2022 08.
Article in English | MEDLINE | ID: covidwho-1974011

ABSTRACT

BACKGROUND: Previous research has demonstrated a tendency for individuals to mentally linearize nonlinear trends, leading to forecast errors. The present research notes that prior conceptualizations of these linear biases do not make identical predictions and examines how linear biases affect forecasts and risk perceptions of an unfolding epidemic. METHODS: This research uses an online experiment and a preregistered direct replication in a different online participant pool (total N = 608) to assess the trajectories of forecasts and risk perceptions over time in an unfolding epidemic. RESULTS: Framing the progress of the epidemic using total cases (v. the rate of new cases) leads to higher forecasts. This research also finds that the effect of frame varies over different time points in the epidemic and differs for forecasts versus risk perceptions. Finally, the effect of frame for forecasted totals is weaker among more numerate individuals. LIMITATIONS: The studies use repeated measures that occur in 1 session rather than over the course of several months and involve a smooth epidemic curve rather than a noisy one with jagged case counts. CONCLUSIONS: This research compares prior conceptualizations of linear biases and yields data with implications both for theory on linear biases and for communicators involved in disseminating information about epidemics. HIGHLIGHTS: Framing the progress of the epidemic using total cases (v. the rate of new cases) leads to higher forecasts.The effect of frame varies over different time points in the epidemic and differs for forecasts v. risk perceptions.The effect of frame for forecasted totals is weaker among more numerate individuals.


Subject(s)
Communication , Pandemics , Bias , Forecasting , Humans , Time
12.
AJR Am J Roentgenol ; 218(2): 270-278, 2022 02.
Article in English | MEDLINE | ID: covidwho-1793148

ABSTRACT

BACKGROUND. The need for second visits between screening mammography and diagnostic imaging contributes to disparities in the time to breast cancer diagnosis. During the COVID-19 pandemic, an immediate-read screening mammography program was implemented to reduce patient visits and decrease time to diagnostic imaging. OBJECTIVE. The purpose of this study was to measure the impact of an immediate-read screening program with focus on disparities in same-day diagnostic imaging after abnormal findings are made at screening mammography. METHODS. In May 2020, an immediate-read screening program was implemented whereby a dedicated breast imaging radiologist interpreted all screening mammograms in real time; patients received results before discharge; and efforts were made to perform any recommended diagnostic imaging during the visit (performed by different radiologists). Screening mammographic examinations performed from June 1, 2019, through October 31, 2019 (preimplementation period), and from June 1, 2020, through October 31, 2020 (postimplementation period), were retrospectively identified. Patient characteristics were recorded from the electronic medical record. Multivariable logistic regression models incorporating patient age, race and ethnicity, language, and insurance type were estimated to identify factors associated with same-day diagnostic imaging. Screening metrics were compared between periods. RESULTS. A total of 8222 preimplementation and 7235 postimplementation screening examinations were included; 521 patients had abnormal screening findings before implementation, and 359 after implementation. Before implementation, 14.8% of patients underwent same-day diagnostic imaging after abnormal screening mammograms. This percentage increased to 60.7% after implementation. Before implementation, patients who identified their race as other than White had significantly lower odds than patients who identified their race as White of undergoing same-day diagnostic imaging after receiving abnormal screening results (adjusted odds ratio, 0.30; 95% CI, 0.10-0.86; p = .03). After implementation, the odds of same-day diagnostic imaging were not significantly different between patients of other races and White patients (adjusted odds ratio, 0.92; 95% CI, 0.50-1.71; p = .80). After implementation, there was no significant difference in race and ethnicity between patients who underwent and those who did not undergo same-day diagnostic imaging after receiving abnormal results of screening mammography (p > .05). The rate of abnormal interpretation was significantly lower after than it was before implementation (5.0% vs 6.3%; p < .001). Cancer detection rate and PPV1 (PPV based on positive findings at screening examination) were not significantly different before and after implementation (p > .05). CONCLUSION. Implementation of the immediate-read screening mammography program reduced prior racial and ethnic disparities in same-day diagnostic imaging after abnormal screening mammograms. CLINICAL IMPACT. An immediate-read screening program provides a new paradigm for improved screening mammography workflow that allows more rapid diagnostic workup with reduced disparities in care.


Subject(s)
Breast Neoplasms/diagnostic imaging , COVID-19/prevention & control , Delayed Diagnosis/prevention & control , Healthcare Disparities/statistics & numerical data , Image Interpretation, Computer-Assisted/methods , Mammography/methods , Racial Groups/statistics & numerical data , Adult , Breast/diagnostic imaging , Female , Humans , Middle Aged , Pandemics , Retrospective Studies , SARS-CoV-2 , Time
14.
Med Sci Monit ; 27: e935379, 2021 Dec 30.
Article in English | MEDLINE | ID: covidwho-1593238

ABSTRACT

BACKGROUND This retrospective study aimed to investigate outcomes and hospitalization rates in patients with a confirmed diagnosis of early COVID-19 treated at home with prescribed and non-prescribed treatments. MATERIAL AND METHODS The medical records of a cohort of 158 Italian patients with early COVID-19 treated at home were analyzed. Treatments consisted of indomethacin, low-dose aspirin, omeprazole, and a flavonoid-based food supplement, plus azithromycin, low-molecular-weight heparin, and betamethasone as needed. The association of treatment timeliness and of clinical variables with the duration of symptoms and with the risk of hospitalization was evaluated by logistic regression. RESULTS Patients were divided into 2 groups: group 1 (n=85) was treated at the earliest possible time (<72 h from onset of symptoms), and group 2 (n=73) was treated >72 h after the onset of symptoms. Clinical severity at the beginning of treatment was similar in the 2 groups. In group 1, symptom duration was shorter than in group 2 (median 6.0 days vs 13.0 days, P<0.001) and no hospitalizations occurred, compared with 19.18% hospitalizations in group 2. One patient in group 1 developed chest X-ray alterations and 2 patients experienced an increase in D-dimer levels, compared with 30 and 22 patients, respectively, in group 2. The main factor determining the duration of symptoms and the risk of hospitalization was the delay in starting therapy (P<0.001). CONCLUSIONS This real-world study of patients in the community showed that early diagnosis and early supportive patient management reduced the severity of COVID-19 and reduced the rate of hospitalization.


Subject(s)
COVID-19 Drug Treatment , COVID-19/diagnosis , Hospitalization/statistics & numerical data , Time-to-Treatment/statistics & numerical data , Aged , Aged, 80 and over , Aspirin/therapeutic use , Betamethasone/therapeutic use , Cohort Studies , Dietary Supplements , Early Diagnosis , Female , Flavonoids/therapeutic use , Follow-Up Studies , Heparin, Low-Molecular-Weight/therapeutic use , Humans , Indomethacin/therapeutic use , Italy , Male , Middle Aged , Omeprazole/therapeutic use , Patient Acuity , Retrospective Studies , Risk Assessment , SARS-CoV-2 , Time , Treatment Outcome
15.
J Am Geriatr Soc ; 69(12): 3405-3406, 2021 12.
Article in English | MEDLINE | ID: covidwho-1570822
16.
BMJ ; 375: n2857, 2021 11 24.
Article in English | MEDLINE | ID: covidwho-1533026
17.
Sci Rep ; 11(1): 22630, 2021 11 19.
Article in English | MEDLINE | ID: covidwho-1526105

ABSTRACT

The rapid emergence and expansion of novel SARS-CoV-2 variants threatens our ability to achieve herd immunity for COVID-19. These novel SARS-CoV-2 variants often harbor multiple point mutations, conferring one or more evolutionarily advantageous traits, such as increased transmissibility, immune evasion and longer infection duration. In a number of cases, variant emergence has been linked to long-term infections in individuals who were either immunocompromised or treated with convalescent plasma. In this paper, we used a stochastic evolutionary modeling framework to explore the emergence of fitter variants of SARS-CoV-2 during long-term infections. We found that increased viral load and infection duration favor emergence of such variants. While the overall probability of emergence and subsequent transmission from any given infection is low, on a population level these events occur fairly frequently. Targeting these low-probability stochastic events that lead to the establishment of novel advantageous viral variants might allow us to slow the rate at which they emerge in the patient population, and prevent them from spreading deterministically due to natural selection. Our work thus suggests practical ways to achieve control of long-term SARS-CoV-2 infections, which will be critical for slowing the rate of viral evolution.


Subject(s)
COVID-19/virology , SARS-CoV-2/genetics , COVID-19/therapy , Computer Simulation , Evolution, Molecular , Humans , Immune Evasion , Mutation , Time , Treatment Failure , Viral Load
18.
Sensors (Basel) ; 21(21)2021 Oct 27.
Article in English | MEDLINE | ID: covidwho-1512560

ABSTRACT

Providing a stable, low-price, and safe supply of energy to end-users is a challenging task. The energy service providers are affected by several events such as weather, volatility, and special events. As such, the prediction of these events and having a time window for taking preventive measures are crucial for service providers. Electrical load forecasting can be modeled as a time series prediction problem. One solution is to capture spatial correlations, spatial-temporal relations, and time-dependency of such temporal networks in the time series. Previously, different machine learning methods have been used for time series prediction tasks; however, there is still a need for new research to improve the performance of short-term load forecasting models. In this article, we propose a novel deep learning model to predict electric load consumption using Dual-Stage Attention-Based Recurrent Neural Networks in which the attention mechanism is used in both encoder and decoder stages. The encoder attention layer identifies important features from the input vector, whereas the decoder attention layer is used to overcome the limitations of using a fixed context vector and provides a much longer memory capacity. The proposed model improves the performance for short-term load forecasting (STLF) in terms of the Mean Absolute Error (MAE) and Root Mean Squared Errors (RMSE) scores. To evaluate the predictive performance of the proposed model, the UCI household electric power consumption (HEPC) dataset has been used during the experiments. Experimental results demonstrate that the proposed approach outperforms the previously adopted techniques.


Subject(s)
Machine Learning , Neural Networks, Computer , Forecasting , Time , Weather
19.
PLoS One ; 16(11): e0259282, 2021.
Article in English | MEDLINE | ID: covidwho-1502073

ABSTRACT

Infectious diseases and widespread outbreaks influence different sectors of the economy, including the stock market. In this article, we investigate the effect of EBOV and COVID-19 outbreaks on stock market indices. We employ time-varying and constant bivariate copula methods to measure the dependence structure between the infectious disease equity market volatility index (IEMV) and the stock market indices of several sectors. The results show that the financial and communication services sectors have the highest and the lowest negative dependency on IEMV during the Ebola virus (EBOV) pandemic, respectively. However, the health care and energy sectors have the highest and lowest negative dependency on IEMV during the COVID-19 outbreak, respectively. Therefore, the results confirm the heterogeneous time-varying dependency between infectious diseases and the stock market indices. The finding of our study contributes to the ongoing literature on the impact of disease outbreaks, especially the novel coronavirus outbreak on global large-cap companies in the stock market.


Subject(s)
COVID-19/economics , Cost of Illness , Disease Outbreaks/economics , Hemorrhagic Fever, Ebola/economics , Commerce , Ebolavirus , Humans , Time
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