Information Asymmetry and Share Prices: Analysis of the Use of Social Networks in the Brazilian and U.S. Capital Markets

A crescente globalização faz com que a internet se torne, cada vez mais, parte da rotina das pessoas ao redor do mundo. Com a evolução dainternet, surgiram as redes sociais com o objetivo de facilitar a comunicação entre pessoas, comunidades e, até mesmo, entre corporações. As redes sociais oferecem às companhias uma forma de divulgação de suas informações de modo instantâneo, possibilitando aos usuários destas informações maior agilidade na busca de notícias sobre as companhias nas quais estejam aplicados seus investimentos ou em que desejam investir. Neste contexto, o objetivo do presente trabalho foi analisar o modo pelo qual as redes sociais (Facebook, Twitter e Youtube) afetam o nível de assimetria informacional e a precificação das ações das companhias abertas, tanto brasileiras como estadunidenses, durante o período de 2012. Para atingir o objetivo proposto, foi utilizada a estrutura conceitual do Modelo de Ohlson (1995) a fim de verificar se as informações postadas nas redes sociais afetam a precificação das ações, e como proxy para assimetria informacional utilizou-se da volatilidade dos preços das ações. A amostra compreendeu 170 empresas brasileiras listadas na BM&FBOVESPA e 100 empresas listadas no mercado acionário norte-americano, no ano de 2012. Os resultados apontam que as redes sociais podem afetar o nível de assimetria informacional nesses mercados, mas apenas o Facebook "não oficial" afeta a precificação das ações nas empresas do mercado acionário brasileiro, porém, a análise da sensibilidade indicou que os grupos dos que usam ou não oFacebook não apresentam retornos médios diferentes. Sendo assim, os investidores não devem utilizar essa informação para traçar estratégias que gerem melhores retornos.Increasing globalization has meant the internet becoming ever more part of the routine of people around the world. With the evolution of the internet, social networks have emerged in order to facilitate communication between people, communities and even between corporations. Social networks offer companies a way of instantly releasing information, allowing those who use this information greater flexibility when searching for news about the companies in which they have invested or wish to invest. In this context, the objective of this study was to analyze how social networks (Facebook, Twitter and Youtube) affect levels of information asymmetry and the pricing of shares for Brazilian and U.S. public companies during 2012. To achieve the proposed goal, the conceptual framework of the Ohlson model (1995) was used to verify whether the information posted on social networks affects the pricing of shares, and share price volatility was used as a proxy for information asymmetry. The sample included 170 Brazilian companies listed on the BM&FBOVESPA and 100 companies listed on the U.S. stock market in 2012. The results show that social networks can affect levels of information asymmetry in these markets, but only "unofficial" Facebook affects the pricing of shares for companies in the Brazilian stock market, although sensitivity analysis indicated that the groups that use and those that do not use Facebook do not exhibit different average returns. Thus, investors should not use this information to devise strategies to generate better returns

Defoliation intensity and performance of soybean plants with different growth habits

The objective of this work was to evaluate the influence of the level of artificial defoliation, applied in stages V6 and R2, on the quality and yield components of soybean seeds. The experiment was conducted in a greenhouse in the municipality of Cascavel, Paraná State, Brazil. The experimental design was a randomized block with four replications, in a 5 x 2 x 2 factorial scheme (five levels of defoliation x two cultivars, two phenological stages (V6: fifth fully developed trifoliolate leaf and R2: full flowering), two growth habits). The analyzed variables were mass of 100 seeds, number of pods per plant, seed number per plant, seed number per pod, germination, dry matter of seedlings and length of shoot and roots of seedlings. Defoliation above 50% results in the reduction of the number of pods and seeds per plant to grow indeterminate growth and reduction in the mass of 100 seeds for cultivars of determined growth

Unbalanced relationships: insights into the interaction between gut microbiota, geohelminths, and schistosomiasis

Hosts and their microbiota and parasites have co-evolved in an adaptative relationship since ancient times. The interaction between parasites and intestinal bacteria in terms of the hosts’ health is currently a subject of great research interest. Therapeutic interventions can include manipulations of the structure of the intestinal microbiota, which have immunological interactions important for modulating the host’s immune system and for reducing inflammation. Most helminths are intestinal parasites; the intestinal environment provides complex interactions with other microorganisms in which internal and external factors can influence the composition of the intestinal microbiota. Moreover, helminths and intestinal microorganisms can modulate the host’s immune system either beneficially or harmfully. The immune response can be reduced due to co-infection, and bacteria from the intestinal microbiota can translocate to other organs. In this way, the treatment can be compromised, which, together with drug resistance by the parasites makes healing even more difficult. Thus, this work aimed to understand interactions between the microbiota and parasitic diseases caused by the most important geohelminths and schistosomiasis and the consequences of these associations

Brazilian consortium for the study on renal diseases associated with COVID-19 : a multicentric effort to understand SARS-CoV-2-related nephropathy

Kidney involvement appears to be frequent in coronavirus disease 2019 (COVID-19). Despite this, information concerning renal involvement in COVID-19 is still scarce. Several mechanisms appear to be involved in the complex relationship between the virus and the kidney. Also, different morphological patterns have been described in the kidneys of patients with COVID-19. For some authors, however, this association may be just a coincidence. To investigate this issue, we propose assessing renal morphology associated with COVID-19 at the renal pathology reference center of federal university hospitals in Brazil. Data will come from a consortium involving 17 federal university hospitals belonging to Empresa Brasileira de Serviços Hospitalares (EBSERH) network, as well as some state hospitals and an autopsy center. All biopsies will be sent to the referral center for renal pathology of the EBSERH network. The data will include patients who had coronavirus disease, both alive and deceased, with or without pre-existing kidney disease. Kidney biopsies will be analyzed by light, fluorescence, and electron microscopy. Furthermore, immunohistochemical (IHC) staining for various inflammatory cells (i.e., cells expressing CD3, CD20, CD4, CD8, CD138, CD68, and CD57) as well as angiotensin-converting enzyme 2 (ACE2) will be performed on paraffinized tissue sections. In addition to ultrastructural assays, in situ hybridization (ISH), IHC and reverse transcription-polymerase chain reaction (RT-PCR) will be used to detect Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) in renal tissue. For the patients diagnosed with Collapsing Glomerulopathy, peripheral blood will be collected for apolipoprotein L-1 (APOL1) genotyping. For patients with thrombotic microangiopathy, thrombospondin type 1 motif, member 13 (ADAMTS13), antiphospholipid, and complement panel will be performed. The setting of this study is Brazil, which is second behind the United States in highest confirmed cases and deaths. With this complete approach, we hope to help define the spectrum and impact, whether immediate or long-term, of kidney injury caused by SARS-CoV-2

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)

From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions