A Nonparametric Model of Frontiers

In this paper we propose a nonparametric regression frontier model that assumes no specific parametric family of densities for the unobserved stochastic component that represents efficiency in the model. Nonparametric estimation of the regression frontier is obtained using a local linear estimator that is shown to be consistent and $\sqrt{nh_n}$ asymptotically normal under standard assumptions. The estimator we propose envelops the data but is not inherently biased as Free Disposal Hull - FDH or Data Envelopment Analysis - DEA estimators. It is also more robust to extreme values than the aforementioned estimators. A Monte Carlo study is performed to provide preliminary evidence on the estimator's finite sample properties and to compare its performance to a bias corrected FDH estimatononparametric regression frontier, local linear estimation, U statistics.

The evolutionary ecology of interactive synchronism: The illusion of the optimal phenotype

In this article, we discuss some ecological-evolutionary strategies that allow synchronization of organisms, resources, and conditions. Survival and reproduction require synchronization of life cycles of organisms with favourable environmental and ecological features and conditions. This interactive synchronization can occur directly, through pairwise or diffuse co-evolution, or indirectly, for example, as a result of actions of ecosystem engineers and facilitator species. Observations of specific interactions, especially those which have coevolved, may give the false impression that evolution results in optimal genotypes or phenotypes. However, some phenotypes may arise under evolutionary constraints, such as simultaneous evolution of multiple traits, lack of a chain of fit transitional forms leading to an optimal phenotype, or by limits inherent in the process of selection, set by the number of selective deaths and by interference between linked variants. Although there are no optimal phenotypes, optimization models applied to particular species may be useful for a better understanding of the nature of adaptations. The evolution of adaptive strategies results in variable life histories. These strategies can minimize adverse impacts on the fitness of extreme or severe environmental conditions on survival and reproduction, and may include reproductive strategies such as semelparity and iteroparity, or morphological, physiological, or behavioural traits such as diapause, seasonal polyphenism, migration, or bet-hedging. However, natural selection cannot indefinitely maintain intra-population variation, and lack of variation can ultimately extinguish populations

13CO2 recovery fraction in expired air of septic patients under mechanical ventilation

The continuous intravenous administration of isotopic bicarbonate (NaH13CO2) has been used for the determination of the retention of the 13CO2 fraction or the 13CO2 recovered in expired air. This determination is important for the calculation of substrate oxidation. The aim of the present study was to evaluate, in critically ill patients with sepsis under mechanical ventilation, the 13CO2 recovery fraction in expired air after continuous intravenous infusion of NaH13CO2 (3.8 µmol/kg diluted in 0.9% saline in ddH2O). A prospective study was conducted on 10 patients with septic shock between the second and fifth day of sepsis evolution (APACHE II, 25.9 ± 7.4). Initially, baseline CO2 was collected and indirect calorimetry was also performed. A primer of 5 mL NaH13CO2 was administered followed by continuous infusion of 5 mL/h for 6 h. Six CO2 production (VCO2) measurements (30 min each) were made with a portable metabolic cart connected to a respirator and hourly samples of expired air were obtained using a 750-mL gas collecting bag attached to the outlet of the respirator. 13CO2 enrichment in expired air was determined with a mass spectrometer. The patients presented a mean value of VCO2 of 182 ± 52 mL/min during the steady-state phase. The mean recovery fraction was 0.68 ± 0.06%, which is less than that reported in the literature (0.82 ± 0.03%). This suggests that the 13CO2 recovery fraction in septic patients following enteral feeding is incomplete, indicating retention of 13CO2 in the organism. The severity of septic shock in terms of the prognostic index APACHE II and the sepsis score was not associated with the 13CO2 recovery fraction in expired air.Pró-Reitoria de Pesquisa da Universidade de São Paulo (USP)(FAEPA) Fundação de Amparo ao Ensino, Pesquisa e AssistênciaFAPES

Alfabetizaçao de idosos no Brasil : O direito á educaçao no olhar de quem aprende

Trata-se de uma pesquisa qualitativa de cunho fenomenológico realizada com idosos em processo de alfabetizaçao que procurou identificar práticas curriculares exitosas no desenvolvimento da oralidade, da escrita e da leitura de alfabetizandos(as) com mais de 65 anos de idade. A inquietaçao que gerou o tema/problema é parte do compromisso do programa de ensino, pesquisa e extensao TEIA - Trabalho Integrado em Alfabetizaçao de Jovens e Adultos que coordenamos no Departamento de Pedagogia da Universidade do Estado de Santa Catarina. Foram selecionados intencionalmente cinco participantes residentes na Regiao da Grande Florianópolis. Do ponto de vista dos processos de leitura e escrita, as entrevistas analisadas apontaram as seguintes dimensoes: o desejo de ler e ampliaçao dos repertórios de leitura por meio da alfabetizaçao; a alegria de ler na terceira idade e o poder da escrita nas diferentes situaçoes da vida. Este trabalho reafirma o compromisso de uma educaçao inclusiva. Entende-se que todos (as) têm o direito de ?dizerem? as suas palavras. Compreender este mundo e reinventá-l

The empirics of the Solow growth model: Long-term evidence

In this paper we reassess the standard Solow growth model, using a dynamic panel data approach. A new methodology is chosen to deal with this problem. First, unit root tests for individual country time series were run. Second, panel data unit root and cointegration tests were performed. Finally, the panel cointegration dynamics is estimated by (DOLS) method. The resulting evidence supports roughly one-third capital share in income, a.Economic growth, panel data, unit root, cointegration and convergence

Wheel next steps

The case study examines the two more traditional possible alternatives for Wheel, a healthcare platform in the United States of America. This case emphasizes debating IPO versus Private Fundraising, bringing divergent opinions from two financial advisors. The company in question just closed the last round in January 2022, therefore, as per usual, the management team is considering its next steps