•This paper examines the effects of supermarket loyalty programs on the demand for private labels.•I find a significant effect of loyalty programs on consumer preferences for PLs.•Membership reduces ...consumers’ price sensitivity for the products sold by the supermarket they are members of.•Membership increases consumers’ price sensitivity for products sold by supermarkets they are not members of.•These effects are weaker for households that are members of the loyalty programs of multiple supermarkets.
This paper examines the effects of supermarket loyalty programs (LPs) on the demand for private labels (PLs). Using transaction level data on grocery purchases and individual level information on the membership of loyalty programs, I estimate a model of demand in which membership may affect the consumers’ valuation for PLs, their sensitivity to price changes and have spillover effects on both named brands (NBs) and rivals’ PLs. My identification strategy of the membership effect exploits observed variation in shopping patterns at the consumer level over time and includes a control function using LP characteristics as instrumental variables to account for a potential selection bias related to unobserved factors of the membership decision. I find a significant effect of LPs on consumer preferences for PLs. Compared to non-members, membership reduces consumers’ price sensitivity for the products sold by the supermarket they are members of, but increases it for products sold by supermarkets they are not members of. These effects are weaker for households that are members of the LPS of multiple supermarkets. Further, I use my demand model along with a supply model to simulate counterfactual scenarios in which supermarkets unilaterally modify their LPs to make it more difficult for customers to benefit from them. I find a considerable decrease in the demand for PLs and an increase in the demand for NBs. In response, supermakets decrease PLs’ prices and increase NBs prices in order to partially offset the impact on PLs’ demand.
•Early non-pharmacological interventions are necessary limit the spread of COVID-19.•In low to middle-income countries, there are limited resources to face the pandemic.•Symptoms (i.e. anosmia) can ...be used to apply early strategies in suspicious cases.•Logistic regression provides interpretability in prediction analysis.•Machine learning analysis aids prediction because of its capacity of data synthesis.
Symptoms-based models for predicting SARS-CoV-2 infection may improve clinical decision-making and be an alternative to resource allocation in under-resourced settings. In this study we aimed to test a model based on symptoms to predict a positive test result for SARS-CoV-2 infection during the COVID-19 pandemic using logistic regression and a machine-learning approach, in Bogotá, Colombia. Participants from the CoVIDA project were included. A logistic regression using the model was chosen based on biological plausibility and the Akaike Information criterion. Also, we performed an analysis using machine learning with random forest, support vector machine, and extreme gradient boosting. The study included 58,577 participants with a positivity rate of 5.7%. The logistic regression showed that anosmia (aOR = 7.76, 95% CI 6.19, 9.73), fever (aOR = 4.29, 95% CI 3.07, 6.02), headache (aOR = 3.29, 95% CI 1.78, 6.07), dry cough (aOR = 2.96, 95% CI 2.44, 3.58), and fatigue (aOR = 1.93, 95% CI 1.57, 2.93) were independently associated with SARS-CoV-2 infection. Our final model had an area under the curve of 0.73. The symptoms-based model correctly identified over 85% of participants. This model can be used to prioritize resource allocation related to COVID-19 diagnosis, to decide on early isolation, and contact-tracing strategies in individuals with a high probability of infection before receiving a confirmatory test result. This strategy has public health and clinical decision-making significance in low- and middle-income settings like Latin America.
This paper aims to show, first, that Peirce's theory of the origin of
abduction in Aristotle's Prior Analytics II.25 is
mistaken, for Peirce forced the dialectical syllogisms of that passage to
...resemble his conception of abduction as a syllogism of the second figure that
attempts to infer a minor premise. Second, it aims to show that there are
abductive syllogisms in other passages of Aristotle's work that Peirce
neglected. In those passages, Aristotle distinguished between the syllogism that
infers the fact and the one that infers the reason. The latter is a syllogism in
the second figure that explains the cause of a phenomenon, and it has been
qualified by ancient and modern comentators as the syllogism of discovery.
Moreover, Aristotle related that kind of syllogism with the mental capacity of
discovering the cause, namely, anchinoia, translated as the
skill of conjecture or sagacity.
Epidemiologic surveillance of COVID-19 is essential to collect and analyse data to improve public health decision making during the pandemic. There are few initiatives led by public-private alliances ...in Colombia and Latin America. The CoVIDA project contributed with RT-PCR tests for SARS-CoV-2 in mild or asymptomatic populations in Bogotá. The present study aimed to determine the factors associated with SARS-CoV-2 infection in working adults.
COVID-19 intensified sentinel epidemiological surveillance study, from April 18, 2020, to March 29, 2021. The study included people aged 18 years or older without a history of COVID-19. Two main occupational groups were included: healthcare and essential services workers with high mobility in the city. Social, demographic, and health-related factors were collected via phone survey. Afterwards, the molecular test was conducted to detect SARS-CoV-2 infection.
From the 58,638 participants included in the study, 3,310 (5·6%) had a positive result. A positive result was associated with the age group (18-29 years) compared with participants aged 60 or older, participants living with more than three cohabitants, living with a confirmed case, having no affiliation to the health system compared to those with social health security, reporting a very low socioeconomic status compared to those with higher socioeconomic status, and having essential occupations compared to healthcare workers.
The CoVIDA study showed the importance of intensified epidemiological surveillance to identify groups with increased risk of infection. These groups should be prioritised in the screening, contact tracing, and vaccination strategies to mitigate the pandemic.
The CoVIDA study was funded through donors managed by the philanthropy department of Universidad de los Andes.
Background and Objectives: Particulate Matter (PM), particles of variable but small diameter can penetrate the respiratory system via inhalation, causing respiratory and/or cardiovascular diseases. ...This study aims to evaluate the association of environmental particulate matter (PM2.5) and black carbon (BC) with respiratory health in users of different transport modes in four roads in Bogotá. Materials and Methods: this was a mixed-method study (including a cross sectional study and a qualitative description of the air quality perception), in 300 healthy participants, based on an exploratory sequential design. The respiratory effect was measured comparing the changes between pre- and post-spirometry. The PM2.5 and black carbon (BC) concentrations were measured using portable devices. Inhaled doses were also calculated for each participant according to the mode and route. Perception was approached through semi-structured interviews. The analysis included multivariate models and concurrent triangulation. Results: The concentration of matter and black carbon were greater in bus users (median 50.67 µg m−3; interquartile range (–IR): 306.7). We found greater inhaled dosages of air pollutants among bike users (16.41 µg m−3). We did not find changes in the spirometry parameter associated with air pollutants or transport modes. The participants reported a major sensory influence at the visual and olfactory level as perception of bad air quality. Conclusions: We observed greater inhaled doses among active transport users. Nevertheless, no pathological changes were identified in the spirometry parameters. People’s perceptions are a preponderant element in the assessment of air quality.
A new coronavirus emerged in 2019 in Wuhan, China named Severe Acute Respiratory Syndrome type 2 coronavirus (SARS-CoV-2). Later, this virus spread worldwide, causing a disease called coronavirus ...disease (COVID-19). To control the outbreak, many countries announced mandatory quarantine; thus, people changed their lifestyles and started engaging in most activities from home. This review explains how some dermatological pathologies may be precipitated by prolonged stays at home, considering that quarantine was a widely used public health measure during 2020. Most of these dermatoses had to be seen, diagnosed, and treated through tele-dermatology, a remote health care system that took force during the COVID-19 pandemic because of its ease and efficiency in connecting health care professionals and their patients; therefore, reducing the risk of contagion and costs associated to medical care. This review of the principal dermatologic conditions during confinement could allow for a better preparation of health professionals.
Moral disengagement mechanisms are strategies to make immoral actions appear moral. This study explores their us-age by two Colombian illegal armed groups (guerrillas and paramilitaries), as well as ...differences between the groups. The analysis covered 367 communiqués issued in 55 months. A deductive content analysis revealed that the most used mechanisms were: attribution of blame, euphemistic labeling, moral justification and labeling with undesirable names. Results showed differences between groups only in the number of press releases, but not in frequency or type of the mechanisms used. The findings are analyzed in the discussion section in relation to the theory of dissonance, extreme violence and motives for joining illegal armed groups.
In Peru, HIV is concentrated among men who have sex with men (MSM) and transgender women (TGW). Between June 2015 and August 2016, 591 HIV-positive MSM and TGW were recruited at five clinical care ...sites in Lima, Peru. We found that 82.4% of the participants had achieved viral suppression (VS; VL < 200) and 73.6% had achieved maximal viral suppression (MVS; VL < 50). Multivariable modeling indicated that patients reporting transportation as a barrier to HIV care were less likely to achieve VS (aOR = 0.47; 95% CI = 0.30-0.75) and MVS (aOR = 0.56; 95% CI = 0.37-0.84). Alcohol use disorders were negatively associated with MVS (aOR = 0.62; 95% CI = 0.30-0.75) and age was positively associated with achieving MVS (aOR = 1.29; 95% CI = 1.04-1.59). These findings underscore the need for more accessible HIV care with integrated behavioral health services in Lima, Peru.
Rheumatoid arthritis and systemic lupus erythematosus are two highly prevalent autoimmune diseases that generate disability and low quality of life. The innate immune system, a long-forgotten issue ...in autoimmune diseases, is becoming increasingly important and represents a new focus for the treatment of these entities. This review highlights the role that innate immune system plays in the pathophysiology of rheumatoid arthritis and systemic lupus erythematosus. The role of the innate immune system in rheumatoid arthritis and systemic lupus erythematosus pathophysiology is not only important in early stages but is essential to maintain the immune response and to allow disease progression. In rheumatoid arthritis, genetic and environmental factors are involved in the initial stimulation of the innate immune response in which macrophages are the main participants, as well as fibroblast-like synoviocytes. In systemic lupus erythematosus, all the cells contribute to the inflammatory response, but the complement system is the major effector of the inflammatory process. Detecting alterations in the normal function of these cells, besides its contribution to the understanding of the pathophysiology of autoimmune diseases, could help to establish new treatment strategies for these diseases.
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