Month: January 2021

Dynamics of informal risk sharing in collective index insurance

Fernando P. Santos, Jorge M. Pacheco, Francisco C. Santos & Simon A. Levin
Nature Sustainability (2021)

Extreme weather events often prevent low-income farmers from accessing high-return technologies that would enhance their productivity. As a result, they often fall into poverty traps, a problem likely to worsen as the frequency of weather disasters increases due to climate change. Insurance offers, in principle, a solution for this conundrum and a means to guarantee households’ wellbeing. Group collective index insurance constitutes an alternative to indemnity or individual index insurance, and has the potential to alleviate basis risk through within-group informal transfers. Here we show that collective index insurance introduces a coordination dilemma of insurance adoption: socially optimal outcomes are obtained when everyone adopts insurance; however, a minimum fraction of contributors is necessary before the effects of basis risk can be averaged out and individuals start taking up insurance. We further show that additional mechanisms—such as local peer monitoring and defector exclusion—are necessary to stabilize informal transfers and collective index insurance adoption. Together, collective index insurance and informal transfers may thus constitute a practical instrument to improve sustainability in developing countries.

Read the full article at: www.nature.com

Social Media Insights Into US Mental Health During the COVID-19 Pandemic: Longitudinal Analysis of Twitter Data 

Danny Valdez, Marijn ten Thij, Krishna Bathina, Lauren A Rutter, Johan Bollen

J Med Internet Res 2020;22(12):e21418

Background: The COVID-19 pandemic led to unprecedented mitigation efforts that disrupted the daily lives of millions. Beyond the general health repercussions of the pandemic itself, these measures also present a challenge to the world’s mental health and health care systems. Considering that traditional survey methods are time-consuming and expensive, we need timely and proactive data sources to respond to the rapidly evolving effects of health policy on our population’s mental health. Many people in the United States now use social media platforms such as Twitter to express the most minute details of their daily lives and social relations. This behavior is expected to increase during the COVID-19 pandemic, rendering social media data a rich field to understand personal well-being.

Objective: This study aims to answer three research questions: (1) What themes emerge from a corpus of US tweets about COVID-19? (2) To what extent did social media use increase during the onset of the COVID-19 pandemic? and (3) Does sentiment change in response to the COVID-19 pandemic?

Methods: We analyzed 86,581,237 public domain English language US tweets collected from an open-access public repository in three steps. First, we characterized the evolution of hashtags over time using latent Dirichlet allocation (LDA) topic modeling. Second, we increased the granularity of this analysis by downloading Twitter timelines of a large cohort of individuals (n=354,738) in 20 major US cities to assess changes in social media use. Finally, using this timeline data, we examined collective shifts in public mood in relation to evolving pandemic news cycles by analyzing the average daily sentiment of all timeline tweets with the Valence Aware Dictionary and Sentiment Reasoner (VADER) tool.

Results: LDA topics generated in the early months of the data set corresponded to major COVID-19–specific events. However, as state and municipal governments began issuing stay-at-home orders, latent themes shifted toward US-related lifestyle changes rather than global pandemic-related events. Social media volume also increased significantly, peaking during stay-at-home mandates. Finally, VADER sentiment analysis scores of user timelines were initially high and stable but decreased significantly, and continuously, by late March.

Conclusions: Our findings underscore the negative effects of the pandemic on overall population sentiment. Increased use rates suggest that, for some, social media may be a coping mechanism to combat feelings of isolation related to long-term social distancing. However, in light of the documented negative effect of heavy social media use on mental health, social media may further exacerbate negative feelings in the long-term for many individuals. Thus, considering the overburdened US mental health care structure, these findings have important implications for ongoing mitigation efforts.

Read the full article at: www.jmir.org

The multidisciplinary nature of COVID-19 research

Ricardo Arencibia-Jorge, Lourdes García-García, Ernesto Galbán-Rodríguez, Humberto Carrillo-Calvet

Objective We analyzed the scientific output after COVID-19 and contrasted it with studies published in the aftermath of seven epidemics/pandemics: Severe Acute Respiratory Syndrome (SARS), Influenza A virus H5N1 and Influenza A virus H1N1 human infections, Middle East Respiratory Syndrome (MERS), Ebola virus disease, Zika virus disease, and Dengue.

Design/Methodology/Approach We examined bibliometric measures for COVID-19 and the rest of studied epidemics/pandemics. Data were extracted from Web of Science, using its journal classification scheme as a proxy to quantify the multidisciplinary coverage of scientific output. We proposed a novel Thematic Dispersion Index (TDI) for the analysis of pandemic early stages.

Results/Discussion The literature on the seven epidemics/pandemics before COVID-19 has shown explosive growth of the scientific production and continuous impact during the first three years following each emergence or re-emergence of the specific infectious disease. A subsequent decline was observed with the progressive control of each health emergency. We observed an unprecedented growth in COVID-19 scientific production. TDI measured for COVID-19 (29,4) in just six months, was higher than TDI of the rest (7,5 to 21) during the first three years after epidemic initiation.

Conclusions COVID-19 literature showed the broadest subject coverage, which is clearly a consecuence of its social, economic, and political impact. The proposed indicator (TDI), allowed the study of multidisciplinarity, differentiating the thematic complexity of COVID-19 from the previous seven epidemics/pandemics.

Originality/Value The multidisciplinary nature and thematic complexity of COVID-19 research were successfully analyzed through a scientometric perspective.

Read the full article at: www.biorxiv.org

A scaling law in CRISPR repertoire sizes arises from avoidance of autoimmunity

Hanrong Chen, Andreas Mayer, Vijay Balasubramanian
Some bacteria and archaea possess an adaptive immune system that maintains a memory of past viral infections as DNA elements called spacers, stored in the CRISPR loci of their genomes. This memory is used to mount targeted responses against threats. However, cross-reactivity of CRISPR targeting mechanisms suggests that incorporation of foreign spacers can also lead to autoimmunity. We show that balancing antiviral defense against autoimmunity predicts a scaling law relating spacer length and CRISPR repertoire size. By analyzing a database of microbial CRISPR-Cas systems, we find that the predicted scaling law is realized empirically across prokaryotes, and arises through the proportionate use of different CRISPR types by species differing in the size of immune memory. In contrast, strains with nonfunctional CRISPR loci do not show this scaling. We also demonstrate that simple population-level selection mechanisms can generate the scaling, along with observed variations between strains of a given species.

Read the full article at: arxiv.org

The world is not a theorem

Stuart A. Kauffman, Andrea Roli
The evolution of the biosphere unfolds as a luxuriant generative process of new living forms and functions. Organisms adapt to their environment, and exploit novel opportunities that are created in this continuous blooming dynamics. Affordances play a fundamental role in the evolution of the biosphere, as they represent the opportunities organisms may choose for achieving their goals, thus actualizing what is in potentia. In this paper we maintain that affordances elude a formalization in mathematical terms: we argue that it is not possible to apply set theory to affordances, therefore we cannot devise a mathematical theory of affordances and the evolution of the biosphere.

https://arxiv.org/abs/2101.00284v1