Aplicabilidade da teoria do caos a organizações

Objetivou-se compreender os fundamentos da Teoria do Caos na gestão das empresas, a existência de elementos típicos da Teoria do Caos, nos processos de planejamento, e variáveis controláveis que previnam o caos de ruptura. E se a visão, missão e objetivos consistem em atratores que evitam a instalação do caos de ruptura; e variáveis e faixas de controle utilizadas pelos dirigentes para evitar o caos de ruptura. A metodologia qualitativa empregou estudo exploratório, para identificar as variáveis e faixas de controle empregadas. Estudaram-se dez empresas, da Grande Belo Horizonte, evidenciando-se elementos típicos da Teoria do Caos nos processos de planejamento, e variáveis controláveis que podem evitar o caos de ruptura. Os resultados validaram as proposições teóricas iniciais, indicando a possibilidade da utilização dos conceitos da Teoria do Caos e controle de rupturas em mercados altamente competitivos

Consistent patterns of common species across tropical tree communities

Trees structure the Earth’s most biodiverse ecosystem, tropical forests. The vast number of tree species presents a formidable challenge to understanding these forests, including their response to environmental change, as very little is known about most tropical tree species. A focus on the common species may circumvent this challenge. Here we investigate abundance patterns of common tree species using inventory data on 1,003,805 trees with trunk diameters of at least 10 cm across 1,568 locations1,2,3,4,5,6 in closed-canopy, structurally intact old-growth tropical forests in Africa, Amazonia and Southeast Asia. We estimate that 2.2%, 2.2% and 2.3% of species comprise 50% of the tropical trees in these regions, respectively. Extrapolating across all closed-canopy tropical forests, we estimate that just 1,053 species comprise half of Earth’s 800 billion tropical trees with trunk diameters of at least 10 cm. Despite differing biogeographic, climatic and anthropogenic histories7, we find notably consistent patterns of common species and species abundance distributions across the continents. This suggests that fundamental mechanisms of tree community assembly may apply to all tropical forests. Resampling analyses show that the most common species are likely to belong to a manageable list of known species, enabling targeted efforts to understand their ecology. Although they do not detract from the importance of rare species, our results open new opportunities to understand the world’s most diverse forests, including modelling their response to environmental change, by focusing on the common species that constitute the majority of their trees.Publisher PDFPeer reviewe

Zika virus infection in pregnancy: a protocol for the joint analysis of the prospective cohort studies of the ZIKAlliance, ZikaPLAN and ZIKAction consortia

INTRODUCTION: Zika virus (ZIKV) infection in pregnancy has been associated with microcephaly and severe neurological damage to the fetus. Our aim is to document the risks of adverse pregnancy and birth outcomes and the prevalence of laboratory markers of congenital infection in deliveries to women experiencing ZIKV infection during pregnancy, using data from European Commission-funded prospective cohort studies in 20 centres in 11 countries across Latin America and the Caribbean. METHODS AND ANALYSIS: We will carry out a centre-by-centre analysis of the risks of adverse pregnancy and birth outcomes, comparing women with confirmed and suspected ZIKV infection in pregnancy to those with no evidence of infection in pregnancy. We will document the proportion of deliveries in which laboratory markers of congenital infection were present. Finally, we will investigate the associations of trimester of maternal infection in pregnancy, presence or absence of maternal symptoms of acute ZIKV infection and previous flavivirus infections with adverse outcomes and with markers of congenital infection. Centre-specific estimates will be pooled using a two-stage approach. ETHICS AND DISSEMINATION: Ethical approval was obtained at each centre. Findings will be presented at international conferences and published in peer-reviewed open access journals and discussed with local public health officials and representatives of the national Ministries of Health, Pan American Health Organization and WHO involved with ZIKV prevention and control activities

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 new improvement for a K shortest paths algorithm

The K shortest paths problem is a well known network optimization problem where it is intended to rank the K shortest paths between an initial and a terminal node in a network. The first algorithm for solving this problem appeared by the fifties and since then several other algorithms have been proposed. These algorithms can be divided into two classes: one based on the Optimality Principle and another based on the determination of a tree of shortest paths. Moreover, in the first of these classes there can be considered labeling algorithms and deletion path algorithms. In this paper an improvement for a known deletion path algorithm is presented which results in the improvement of its execution time complexity when the worst case analysis is considered. Comparative computational experiments are also reported, allowing possible conclusions about the obtained performances when the average case is considered

Etnopedologia e transferência de conhecimento: diálogos entre os saberes indígena e técnico na Terra Indígena Malacacheta, Roraima Ethnopedology and knowledge transfer: dialogue between indians and soil scientists in the Malacacheta Indian Territory, Roraima, Amazon

O conhecimento indígena sobre a pedodiversidade é o objeto principal da etnopedologia. Nesse sentido, a tradição agrícola e cultural dos índios Uapixana, do tronco lingüístico Aruaque, em Roraima, constitui relevante acervo imaterial de valor etnocientífico, sendo valorizada pela Universidade Federal de Roraima em seus cursos superiores de Educação Indígena no Estado. Neste trabalho confrontou-se a experiência etnopedológica dos índios Uapixana com o Sistema Brasileiro de Classificação de Solos, durante o levantamento de solos da Terra Indígena (TI) Malacacheta. O sistema de classificação etnopedológica existente na comunidade indígena Uapixana da TI Malacacheta identifica e separa todos os principais compartimentos ambientais de ocorrência na área, permitindo relacionar aspectos de simples percepção e identificação (cor, textura, profundidade, vegetação) com aspectos cognoscíveis (uso, tipo de cultivo, vocação, etc.). Os índios Uapixana identificam e classificam oito tipos básicos de solos, que ocorrem individualmente ou formando associações: Imii Wyzda'u (Terra Amarelada), Imii Wyza'u (Terra Vermelha), Imii Pudiidiu (Terra Preta), Imii Pudiidiza'u (Terra Roxa), Katy Bara Pudiidiu (Barro Arenoso), Imii Kaxidia'u (Estopa Preta), Imii Katy Bara Pudiidiu Naik Baraka'u (Terra Arenosa Preta e Branca) e Imii Wyzadaza'u Rik Pudiidiu (Miscelânea de Terra Amarela, Roxa e afloramentos de rocha), abordando características morfológicas, físicas e químicas e as principais limitações quanto ao uso agrícola. Há relação evidente entre a dimensão do saber etnopedológico o saber etnoecológico, em sentido amplo. A experiência etnopedológica representa, assim, a extensão de uma abrangente cadeia de inter-relações homem-meio, dentro do princípio universal da ecologia humana da paisagem. O diálogo etnopedológico travado entre a comunidade indígena e os pedólogos trouxe contribuições muito relevantes e mutuamente benéficas: facilitou a transferência de conhecimento entre dois saberes, in loco, desvendando boa parte das relações etnopedológicas e etnoecológicas e refletindo sobre "como" e "por que" cada grupo identificava um dado tipo de solo. Permitiu ainda delinear o esboço da distribuição dos solos com base no saber indígena, utilizando a extrapolação cartográfica disponível ao pedólogo; esse fato facilitou o próprio mapeamento convencional, especialmente no reconhecimento de inclusões e associações de solos. De forma mais destacada, a experiência permitiu ainda uma real comunicação e aproximação entre os agentes do saber (indígenas e técnico), com base na troca e em descobertas mútuas de conhecimentos, gerando uma sinergia que aproxima o técnico e o indígena, com resultados práticos palpáveis, que extrapolam o próprio objetivo inicial do levantamento de solos da TI Malacacheta.<br>Ethnopedology deals mainly with indigenous knowledge on pedo-diversity. In this sense, the agricultural and cultural traditions of the Wapishana Indians in Roraima, of the Arawak linguistic background, constitute a relevant pool of ethno-scientific knowledge in Amazonia. The Federal University of Roraima has increasingly acknowledged their importance in the Indigenous Education undergraduate courses. In this study, the ethnopedological classifications of the Wapishana Indians were confronted with the Brazilian System of Soil Classification in a soil survey of the Malacacheta Indian Territory. The ethnopedological classification of Wapishana Indians identifies and separates all environmental segments of the area, relating easily recognizable aspects of the soilscape (color, texture, depth, vegetation) with observable aspects (land use, cultivation type, suitability). The Wapishana classify eight basic soil types, that occur either separately or in associations: Imii Wyzda'u (Yellowish earth), Imii Wyza'u (Red earth), Imii Pudiidiu (Black Earth), Imii Pudiidiza'u (Dusky-Red Earth), Katy Bara Pudiidiu (Sandy loam), Imii Kaxidia'u (Black spongy), Imii Katy Bara Pudiidiu Naik Baraka'u (Black and White Sandy Ground) and Imii Wyzadaza'u Rik Pudiidiu (Mixed Yellowish earth, Dusky-Red earth and Rock outcrops), based on morphological, physical and chemical attributes, as well as land use limitations. There are clear relationships between the ethnopedological knowledge and the ethno-ecological dimension of the Wapishana culture, in the broadest sense. The ethnopedological observations, thus, represent an expression of the interwoven network of man-environment relationships, seen in a framework of universal principles of human/landscape ecology. The intense ethnopedological dialogue between soil scientists and Indians resulted in enriching, mutually beneficial contributions: the proper knowledge transfer in loco between two different traditions, the clarification of great part of the ethnopedological perceptions of both groups, and the understanding on how and why each group identified a given soil. Moreover, a soil map based on indigenous knowledge was drawn up, in an extrapolation of the cartographical base available to pedologists; this supported the conventional soil mapping of the area as well, especially in the recognition of soil inclusions and associations. Particularly, the experience allowed effective communication and approach of the representatives of indigenous and technical knowledge, based on knowledge transfer and mutual discoveries of understanding, creating synergy effects with promising results, which outreached the original aim of soil mapping of the Malacacheta Indian Territory