The impact of implicit trading costs on trading venue competition

In the last 20 years, the U.S. equity markets structure has been changing drastically. The Securities and Exchange Commission (SEC), driven by numerous studies regarding market competition and economic efficiency, recognizing these two variables as having a positive correlation (Casu & Girardone, 2009; Porter, 1990), started to implement policies against market dominance. On August 29th, 2005, the Regulation National Markets System (Reg NMS) was released to harmonize regulation for equity trading services within the U.S., increasing competition and consumer protection in the trading industry services. Using panel data regarding order execution from September 2016 to December 2016. This research attempted to evaluate the effectiveness of Reg NMS regarding trading venues competition using a multinomial logit demand model for differentiated products with dummy variables to capture a non-observable variable. The results suggest that, even though, implicit trading costs, are essential to estimate the trading demand still exists market dominance in the U.S. trading venues, resulting in unusually inelastic price elasticities

SEMIÓTICA: ALGUMAS QUESTÕES CLÁSSICAS

SEMIÓTICA: ALGUMAS QUESTÕES CLÁSSICA

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

A socio-demographic study of aging in the Portuguese Population - The EPEPP study

The increase in life expectancy (LE) observed in Western societies, has resulted in a steep rise of older population. This stresses the importance of the research on aging, to better adequate health and social care organization and improve the quality of life (QoL). The aim of the EPEPP-1 (abbreviated from the Portuguese name: Estudo do Perfil de Envelhecimento da Populac¸a˜o Portuguesa) study was to characterize the socio-demographic components of the elderly Portuguese population in order to disclose factors that could play a role in the aging process and in the elderly QoL. This observational descriptive study, was performed in 2672 individuals older than 54 years taking into account gender and the residence area (rural vs. urban). A questionnaire about social network (marital status, living alone, the hours spent alone, confidents), and social status (education, occupation) was applied. Social network score revealed significant age and gender trends,women and older people performing worst, but with no difference according to residence area. Almost a third was unmarried and spent eight or more hours per day alone, and a fifth lived alone. Social status revealed that being older female and resident in a rural area quoted worst in the prevalence of illiteracy and undifferentiated occupation. The authors concluded that social isolation, illiteracy and undifferentiated occupation are prevalent in Portuguese older population. Identification of further determinants of isolation, adjustment of procedures to be included in social networks and development of actions directed to education are important fields of intervention influencing the elderly QoL

Impact of urban development on streamflow regime of a Portuguese peri-urban Mediterranean catchment

Purpose: Relatively little is known in the Mediterranean environment about changes in streamflow during urban development in partially urbanized peri-urban catchments. This paper explores the modification of streamflow regime as a consequence of the construction of an enterprise park, a major road, and expansion of residential areas, leading to urban areas increase from 32 to 40 % in a small catchment (6.2 km2), located in the periphery of one of the main cities in central mainland Portugal. Materials and methods: The study was carried out over five hydrological years (October 2008–September 2009 to October 2012–September 2013), including two initial years of pre- and three following years of post-additional urban development. Streamflow was recorded by a V-notch weir at the catchment outlet at 5-min intervals. Rainfall was recorded at a weather station 0.5 km north of the catchment and by five tipping-bucket raingauges installed in January 2011 within the study catchment. Streamflow was converted into runoff and split into baseflow and stormflow components by applying a mathematical low-pass digital filter. Streamflow differences were investigated through changes in (i) annual runoff coefficients, (ii) annual baseflow index, (iii) seasonal baseflow index and stormflow coefficient, and (iv) storm event analysis. Results and discussion: Annual runoff coefficient ranged from 14 to 21 % and storm runoff coefficient from 9 to 14 %, both between the driest 2011/12 and wettest 2012/13. Although these differences were influenced by inter-annual weather variability, a comparison between years with similar rainfall before and after additional urban development showed a 43 % increase in storm runoff. Impacts on streamflow were also noticed through changes on hydrograph: (i) regression lines of storm runoff against rainstorm parameters exhibited higher vertical positions in 2012/13 than 2008/09, (ii) gradual increase in peak flow but with a clear distance between pre- and post- additional urbanization, (iii) quicker response time from 60–75 min to 40–45 min between both periods, and (iv) decrease in recession time from 21–29 h to 7–9 h for the same periods. Conclusions: The dispersed urban pattern and permeable soils provide many overland flow sinks, favouring relatively low storm runoff of the catchment. Nevertheless, the enlargement of impervious surfaces (from 12.8 to 17.0 %) and particularly the storm drainage system installed in new urban areas led to great changes on rainfall–runoff event responses. Urban planning should consider the landscape mosaic of peri-urban areas in order to maximize water infiltration and minimize the impacts on streamflow regime