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  Subjects -> BUSINESS AND ECONOMICS (Total: 3531 journals)
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BUSINESS AND ECONOMICS (1272 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1566 Journals sorted alphabetically
4OR: A Quarterly Journal of Operations Research     Hybrid Journal   (Followers: 10)
Abacus     Hybrid Journal   (Followers: 16)
Accounting Forum     Hybrid Journal   (Followers: 28)
Acta Amazonica     Open Access   (Followers: 6)
Acta Commercii     Open Access   (Followers: 4)
Acta Oeconomica     Full-text available via subscription   (Followers: 3)
Acta Scientiarum. Human and Social Sciences     Open Access   (Followers: 9)
Acta Universitatis Danubius. Œconomica     Open Access   (Followers: 3)
Acta Universitatis Nicolai Copernici Zarządzanie     Open Access   (Followers: 4)
AD-minister     Open Access   (Followers: 3)
Adam Academy : Journal of Social Sciences / Adam Akademi : Sosyal Bilimler Dergisi     Open Access   (Followers: 3)
AdBispreneur : Jurnal Pemikiran dan Penelitian Administrasi Bisnis dan Kewirausahaan     Open Access  
Admisi dan Bisnis     Open Access  
ADR Bulletin     Open Access   (Followers: 6)
Advances in Developing Human Resources     Hybrid Journal   (Followers: 30)
Advances in Economics and Business     Open Access   (Followers: 18)
AfricaGrowth Agenda     Full-text available via subscription   (Followers: 2)
African Affairs     Hybrid Journal   (Followers: 66)
African Business     Full-text available via subscription   (Followers: 2)
African Development Review     Hybrid Journal   (Followers: 40)
African Journal of Business and Economic Research     Full-text available via subscription   (Followers: 7)
African Journal of Business Ethics     Open Access   (Followers: 6)
African Review of Economics and Finance     Open Access   (Followers: 5)
Afro Eurasian Studies     Open Access  
Afro-Asian Journal of Finance and Accounting     Hybrid Journal   (Followers: 8)
Afyon Kocatepe Üniversitesi İktisadi ve İdari Bilimler Fakültesi Dergisi     Open Access   (Followers: 3)
Agronomy     Open Access   (Followers: 12)
Akademik Yaklaşımlar Dergisi     Open Access  
Akademika : Journal of Southeast Asia Social Sciences and Humanities     Open Access   (Followers: 7)
Alphanumeric Journal : The Journal of Operations Research, Statistics, Econometrics and Management Information Systems     Open Access   (Followers: 5)
American Economic Journal : Applied Economics     Full-text available via subscription   (Followers: 230)
American Enterprise Institute     Free   (Followers: 2)
American Journal of Business     Hybrid Journal   (Followers: 20)
American Journal of Business and Management     Open Access   (Followers: 59)
American Journal of Business Education     Open Access   (Followers: 13)
American Journal of Economics and Business Administration     Open Access   (Followers: 30)
American Journal of Economics and Sociology     Hybrid Journal   (Followers: 36)
American Journal of Evaluation     Hybrid Journal   (Followers: 15)
American Journal of Finance and Accounting     Hybrid Journal   (Followers: 23)
American Journal of Health Economics     Full-text available via subscription   (Followers: 15)
American Journal of Industrial and Business Management     Open Access   (Followers: 25)
American Journal of Medical Quality     Hybrid Journal   (Followers: 9)
American Law and Economics Review     Hybrid Journal   (Followers: 28)
ANALES de la Universidad Central del Ecuador     Open Access   (Followers: 3)
Ankara University SBF Journal     Open Access  
Annales de l'Institut Henri Poincare (C) Non Linear Analysis     Full-text available via subscription   (Followers: 1)
Annals in Social Responsibility     Full-text available via subscription  
Annals of Finance     Hybrid Journal   (Followers: 34)
Annals of Operations Research     Hybrid Journal   (Followers: 10)
Annual Review of Economics     Full-text available via subscription   (Followers: 42)
Anuario Facultad de Ciencias Económicas y Empresariales     Open Access   (Followers: 2)
Applied Developmental Science     Hybrid Journal   (Followers: 3)
Applied Economics     Hybrid Journal   (Followers: 53)
Applied Economics Letters     Hybrid Journal   (Followers: 32)
Applied Financial Economics     Hybrid Journal   (Followers: 29)
Applied Mathematical Finance     Hybrid Journal   (Followers: 7)
Applied Stochastic Models in Business and Industry     Hybrid Journal   (Followers: 6)
Apuntes Universitarios     Open Access   (Followers: 1)
Arab Economic and Business Journal     Open Access   (Followers: 7)
Archives of Business Research     Open Access   (Followers: 8)
Arena Journal     Full-text available via subscription   (Followers: 1)
Argomenti. Rivista di economia, cultura e ricerca sociale     Open Access   (Followers: 4)
ASEAN Economic Bulletin     Full-text available via subscription   (Followers: 7)
Asia Pacific Business Review     Hybrid Journal   (Followers: 10)
Asia Pacific Journal of Human Resources     Hybrid Journal   (Followers: 326)
Asia Pacific Journal of Innovation and Entrepreneurship     Open Access   (Followers: 1)
Asia Pacific Viewpoint     Hybrid Journal  
Asia-Pacific Journal of Business Administration     Hybrid Journal   (Followers: 6)
Asia-Pacific Journal of Operational Research     Hybrid Journal   (Followers: 3)
Asia-Pacific Management and Business Application     Open Access   (Followers: 1)
Asian Business Review     Open Access   (Followers: 4)
Asian Case Research Journal     Hybrid Journal   (Followers: 1)
Asian Development Review     Open Access   (Followers: 15)
Asian Economic Journal     Hybrid Journal   (Followers: 11)
Asian Economic Papers     Hybrid Journal   (Followers: 8)
Asian Economic Policy Review     Hybrid Journal   (Followers: 5)
Asian Journal of Accounting and Governance     Open Access   (Followers: 4)
Asian Journal of Business Ethics     Hybrid Journal   (Followers: 11)
Asian Journal of Social Sciences and Management Studies     Open Access   (Followers: 8)
Asian Journal of Sustainability and Social Responsibility     Open Access   (Followers: 2)
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 8)
Asian-pacific Economic Literature     Hybrid Journal   (Followers: 8)
AStA Wirtschafts- und Sozialstatistisches Archiv     Hybrid Journal   (Followers: 5)
ATA Journal of Legal Tax Research     Hybrid Journal   (Followers: 4)
Atlantic Economic Journal     Hybrid Journal   (Followers: 13)
Australasian Journal of Regional Studies, The     Full-text available via subscription   (Followers: 1)
Australian Cottongrower, The     Full-text available via subscription   (Followers: 1)
Australian Economic Papers     Hybrid Journal   (Followers: 39)
Australian Economic Review     Hybrid Journal   (Followers: 4)
Australian Journal of Maritime and Ocean Affairs     Hybrid Journal   (Followers: 9)
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 2)
Baltic Journal of Real Estate Economics and Construction Management     Open Access   (Followers: 2)
Banks in Insurance Report     Hybrid Journal   (Followers: 1)
BBR - Brazilian Business Review     Open Access   (Followers: 5)
Benchmarking : An International Journal     Hybrid Journal   (Followers: 11)
Benefit : Jurnal Manajemen dan Bisnis     Open Access   (Followers: 1)
BER : Consumer Confidence Survey     Full-text available via subscription   (Followers: 4)
BER : Economic Prospects : An Executive Summary     Full-text available via subscription   (Followers: 2)
BER : Economic Prospects : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Intermediate Goods Industries Survey     Full-text available via subscription   (Followers: 1)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription  
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 1)
BER : Survey of Business Conditions in Building and Construction : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Trends : Full Survey     Full-text available via subscription   (Followers: 1)
BER : Wholesale Sector Survey     Full-text available via subscription  
Berkeley Business Law Journal     Free   (Followers: 10)
Beta : Scandinavian Journal of Business Research     Full-text available via subscription  
Beykent Üniversitesi Sosyal Bilimler Dergisi     Open Access  
Bio-based and Applied Economics     Open Access   (Followers: 2)
Biodegradation     Hybrid Journal   (Followers: 1)
Biology Direct     Open Access   (Followers: 9)
Bitlis Eren Üniversitesi İktisadi Ve İdari Bilimler Fakültesi Akademik İzdüşüm Dergisi     Full-text available via subscription  
BizInfo (Blace) Journal of Economics, Management and Informatics     Open Access   (Followers: 1)
Black Enterprise     Full-text available via subscription  
Board & Administrator for Administrators only     Hybrid Journal  
Boletim Técnico do Senac     Open Access  
Border Crossing : Transnational Working Papers     Open Access   (Followers: 4)
Briefings in Real Estate Finance     Hybrid Journal   (Followers: 5)
British Journal of Industrial Relations     Hybrid Journal   (Followers: 39)
Brookings Papers on Economic Activity     Open Access   (Followers: 60)
Brookings Trade Forum     Full-text available via subscription   (Followers: 3)
BRQ Business Research Quarterly     Open Access   (Followers: 2)
Building Sustainable Legacies : The New Frontier Of Societal Value Co-Creation     Full-text available via subscription   (Followers: 1)
Bulletin of Economic Research     Hybrid Journal   (Followers: 19)
Bulletin of Geography. Socio-economic Series     Open Access   (Followers: 5)
Bulletin of Indonesian Economic Studies     Hybrid Journal   (Followers: 4)
Bulletin of the Dnipropetrovsk University. Series : Management of Innovations     Open Access   (Followers: 1)
Business & Entrepreneurship Journal     Open Access   (Followers: 22)
Business & Information Systems Engineering     Hybrid Journal   (Followers: 6)
Business & Society     Hybrid Journal   (Followers: 12)
Business : Theory and Practice / Verslas : Teorija ir Praktika     Open Access   (Followers: 1)
Business and Economic Research     Open Access   (Followers: 10)
Business and Management Horizons     Open Access   (Followers: 14)
Business and Management Research     Open Access   (Followers: 22)
Business and Management Studies     Open Access   (Followers: 13)
Business and Professional Communication Quarterly     Hybrid Journal   (Followers: 7)
Business and Society Review     Hybrid Journal   (Followers: 6)
Business Economics     Hybrid Journal   (Followers: 15)
Business Ethics Quarterly     Full-text available via subscription   (Followers: 14)
Business Ethics: A European Review     Hybrid Journal   (Followers: 19)
Business Horizons     Hybrid Journal   (Followers: 12)
Business Information Review     Hybrid Journal   (Followers: 15)
Business Management and Strategy     Open Access   (Followers: 43)
Business Research     Hybrid Journal   (Followers: 3)
Business Strategy and the Environment     Hybrid Journal   (Followers: 14)
Business Strategy Review     Hybrid Journal   (Followers: 10)
Business Strategy Series     Hybrid Journal   (Followers: 7)
Business Systems & Economics     Open Access   (Followers: 2)
Business Systems Research Journal     Open Access   (Followers: 5)
Business, Economics and Management Research Journal : BEMAREJ     Open Access   (Followers: 3)
Business, Management and Education     Open Access   (Followers: 20)
Business, Peace and Sustainable Development     Full-text available via subscription   (Followers: 4)
Business: Theory and Practice     Open Access  
Bustan     Hybrid Journal  
Cadernos EBAPE.BR     Open Access   (Followers: 1)
Cambridge Journal of Economics     Hybrid Journal   (Followers: 71)
Cambridge Journal of Regions, Economy and Society     Hybrid Journal   (Followers: 12)
Canadian Journal of Administrative Sciences / Revue Canadienne des Sciences de l Administration     Hybrid Journal   (Followers: 1)
Canadian Journal of Economics/Revue Canadienne d`Economique     Hybrid Journal   (Followers: 42)
Canadian journal of nonprofit and social economy research     Open Access   (Followers: 3)
Capitalism Nature Socialism     Hybrid Journal   (Followers: 20)
Cappadocia Academic Review     Open Access  
Case Studies in Business and Management     Open Access   (Followers: 11)
CBU International Conference Proceedings     Open Access   (Followers: 3)
Central European Business Review     Open Access   (Followers: 1)
Central European Journal of Operations Research     Hybrid Journal   (Followers: 5)
Central European Journal of Public Policy     Open Access   (Followers: 3)
CESifo Economic Studies     Hybrid Journal   (Followers: 22)
Chain Reaction     Full-text available via subscription  
Challenge     Full-text available via subscription   (Followers: 5)
China & World Economy     Hybrid Journal   (Followers: 19)
China : An International Journal     Full-text available via subscription   (Followers: 20)
China Economic Journal : The Official Journal of the China Center for Economic Research (CCER) at Peking University     Hybrid Journal   (Followers: 15)
China Economic Review     Hybrid Journal   (Followers: 14)
China Finance Review International     Hybrid Journal   (Followers: 6)
China Nonprofit Review     Hybrid Journal   (Followers: 3)
China perspectives     Open Access   (Followers: 12)
Chinese Economy     Full-text available via subscription   (Followers: 2)
Ciência & Saúde Coletiva     Open Access   (Followers: 2)
Ciencia Sociales y Económicas     Open Access  
CLIO América     Open Access   (Followers: 2)
Cliometrica     Hybrid Journal   (Followers: 5)
COEPTUM     Open Access  
Community Development Journal     Hybrid Journal   (Followers: 27)
Compendium : Cuadernos de Economía y Administración     Open Access  
Compensation & Benefits Review     Hybrid Journal   (Followers: 8)
Competition & Change     Hybrid Journal   (Followers: 11)
Competitive Intelligence Review     Hybrid Journal   (Followers: 2)
Competitiveness Review : An International Business Journal incorporating Journal of Global Competitiveness     Hybrid Journal   (Followers: 5)
Computational Economics     Hybrid Journal   (Followers: 10)
Computational Mathematics and Modeling     Hybrid Journal   (Followers: 9)
Computer Law & Security Review     Hybrid Journal   (Followers: 17)
Computers & Operations Research     Hybrid Journal   (Followers: 12)
Construction Innovation: Information, Process, Management     Hybrid Journal   (Followers: 14)
Contemporary Wales     Full-text available via subscription   (Followers: 1)
Contributions to Political Economy     Hybrid Journal   (Followers: 6)

        1 2 3 4 5 6 7 | Last

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Acta Amazonica
Journal Prestige (SJR): 0.36
Citation Impact (citeScore): 1
Number of Followers: 6  

  This is an Open Access Journal Open Access journal
ISSN (Print) 0044-5967
Published by SciELO Homepage  [716 journals]
  • Allometric models to estimate tree height in northern Amazonian ecotone

    • Abstract: ABSTRACT Allometric models defining the relationship between stem diameter and total tree height in the Amazon basin are important because they refine the estimates of tree carbon stocks and flow in the region. This study tests different allometric models to estimate the total tree height from the stem diameter in an ecotone zone between ombrophilous and seasonal forests in the Brazilian state of Roraima, in northern Amazonia. Stem diameter and total height were measured directly in 65 recently fallen trees (live or dead). Linear and nonlinear regressions were tested to represent the D:H relation in this specific ecotone zone. Criteria for model selection were the standard error of the estimate (Syx) and the adjusted coefficient of determination (R²adj), complemented by the Akaike Information Criterion (AIC). Analysis of residuals of the most parsimonious nonlinear models showed a tendency to overestimate the total tree height for trees in the 20-40 cm diameter range. Application of our best fitted model (Michaelis-Menten) indicated that previously published general equations for the tropics that use diameter as the independent variable can either overestimate tree height in the study area by 10-29% (Weibull models) or underestimate it by 8% (climate-based models). We concluded that our site-specific model can be used in the ecotone forests studied in Roraima because it realistically reflects the local biometric relationships between stem diameter and total tree height. Studies need to be expanded in peripheral areas of northern Amazonia in order to reduce uncertainties in biomass and carbon estimates that use the tree height as a variable in general models.RESUMO Modelos alométricos que definem o relacionamento entre diâmetro do tronco e a altura total da árvore na bacia amazônica são importantes porque refinam as estimativas de fluxo e estoques de carbono arbóreo na região. Este estudo testou diferentes modelos alométricos para estimar a altura total de árvores a partir do diâmetro do tronco em uma zona de ecótono entre florestas ombrófilas e sazonais no estado de Roraima, norte da Amazônia. Diâmetro do tronco e altura total foram medidos de forma direta em 65 árvores tombadas recentemente (vivas e mortas). Regressões linear e não-linear foram testadas para representar a relação D:H nesta zona específica de ecótono. Os critérios de seleção dos modelos foram o erro padrão da estimativa (Syx), o coeficiente de determinação ajustado (R²adj) e o Critério de Informação de Akaike (AIC). A análise dos resíduos dos modelos não-lineares mais parcimoniosos mostrou uma tendência de superestimar a altura total para árvores entre 20-40 cm de diâmetro do tronco. A aplicação do modelo melhor ajustado (Michaelis-Menten) indicou que equações gerais publicadas previamente para os trópicos que usam diâmetro como variável independente podem superestimar em 10-29% (modelos Weibull) ou subestimar em 8% (modelos baseados no clima) a altura das árvores na área de estudo. Nós concluímos que o modelo de melhor ajuste pode ser usado nas florestas ecotonais estudadas em Roraima, porque ele reflete realisticamente o relacionamento biométrico local entre diâmetro do tronco e altura total da árvore. É necessário expandir os estudos para outras áreas periféricas do norte da Amazônia, com o intuito de reduzir as incertezas em estimativas de biomassa e carbono arbóreo que adotem altura da árvore como uma variável em modelos gerais.
  • Evaluation of forest inventory processes in a forest under concession in
           the southwestern Brazilian Amazon

    • Abstract: ABSTRACT Forest inventory procedures are of utmost importance to studies of wood volume stocks, and forest structure and diversity, which provide relevant information to public policies, management plans and ecological research. The present work focused on the performance of inventory techniques in the Amazon region to evaluate wood volume stocks with higher levels of accuracy while maintaining sampling intensity fixed. Two sampling processes were assessed: simple random sampling and two-stage cluster sampling. The processes were evaluated through the allocation of sampling units with different dimensions, and the effectiveness of the generated estimators was analyzed as a function of stand density and basal area. Simple random sampling resulted in the smallest errors, reaching 9% when all species were sampled together. The method depicted forest phytosociological parameters with greater sensitivity, whereas two-stage cluster sampling produced the least accurate estimators and presented slower responses to variation in phytosociological parameters.RESUMO O procedimento de inventário florestal é considerado de alta importância no que concerne estudos de estoque madeireiro, estrutura e diversidade florestal, que fornecem informações relevantes para políticas públicas, planos de manejo e pesquisas ecológicas. O presente trabalho buscou avaliar o desempenho de técnicas de inventário na região Amazônica para estimativa de estoques madeireiros com maior nível de acurácia, mantendo a intensidade amostral fixa. Dois processos de amostragem foram avaliados: amostragem aleatória simples e amostragem em dois estágios. Esses processos foram avaliados através de alocação de unidades amostrais com dimensões distintas, e os estimadores gerados foram analisados em função da densidade de árvores e da área basal. A amostragem aleatória simples produziu os menores erros, alcançando 9% quando todas as espécies foram amostradas conjuntamente, e mostrou-se mais eficiente na detecção de variações em parâmetros fitossociológicos. A amostragem em dois estágios produziu os estimadores menos acurados e apresentou respostas mais lentas às variações em parâmetros fitossociológicos.
  • Do polyembryonic seeds of Carapa surinamensis (Meliaceae) have advantages
           for seedling development'

    • Abstract: ABSTRACT Polyembryony is the differentiation and development of multiple embryos in a single seed. This characteristic can provide advantages, as more than one embryo is produced with the same amount of resources, and the probability of establishment of at least one seedling increases. However, sibling seedlings may also increase competition, affecting development and survival. In the present study, the possible advantages and disadvantages of polyembryony were analyzed in the initial establishment of seedlings of Carapa surinamensis (Meliaceae), a tree species that produces monoembryonic or polyembryonic seeds. In this regard, the development of single seedlings was compared with a pair of seedlings emerging from polyembryonic seeds. We compared the development of seedlings attached to or detached from each other and to the seed resources. We observed two levels of competition: (a) for the seed reserves during germination and initial development, as multiple embryos of C. surinamensis share the same reserves, and (b) for external factors, mostly space for root and shoot development, and also for light. Reducing the competition for external factors by separating the siblings was not enough to reduce the effects of competition for seed reserves in the first six months of development. Nevertheless, viable seedlings were produced in all treatments. Thus, depending on sprout management in the nursery, the number of seedlings per seed can be significantly increased by detaching the seedlings, or more vigorous seedlings can be obtained when only one seedling is maintained.RESUMO Poliembrionia é a diferenciação e o desenvolvimento de múltiplos embriões em uma única semente. Esta característica pode proporcionar diversas vantagens, como aumentar o número de embriões produzidos com a mesma quantidade de recursos, e aumentar a probabilidade de estabelecimento de pelo menos uma plântula de uma única semente. Por outro lado, a competição entre plântulas pode aumentar, afetando seu desenvolvimento e sobrevivência. Neste estudo, foram analisadas as possíveis vantagens e desvantagens da poliembrionia em sementes de andiroba, Carapa surinamensis (Meliaceae), uma espécie arbórea que produz sementes monoembriônicas ou poliembriônicas. Comparamos o desenvolvimento de plântulas únicas com o de pares de plântulas provenientes de sementes poliembriônicas. As plântulas foram mantidas unidas ou separadas entre si e ligadas à ou destacadas da semente. Os resultados revelaram dois níveis de competição: (a) pelas reservas da semente durante a germinação e desenvolvimento inicial da plântula, quando embriões múltiplos de C. surinamensis compartilham as mesmas reservas, e (b) por fatores externos, principalmente espaço para o desenvolvimento da raiz e da parte aérea, e luz. A redução da competição por fatores externos, através da separação das plântulas, não foi suficiente para reduzir os efeitos da competição pelas reservas das sementes nos primeiros seis meses de desenvolvimento. Apesar disso, plântulas viáveis foram produzidas em todos os tratamentos. Assim, dependendo do manejo dos brotos em viveiro, o número de plântulas produzidas pode ser aumentado significativamente por meio da separação entre plântulas, ou o vigor das plântulas pode ser incrementado através de sua manutenção individualizada.
  • Reproductive and feeding biology of the common lancehead Bothrops atrox
           (Serpentes, Viperidae) from central and southwestern Brazilian Amazonia

    • Abstract: ABSTRACT The pitviper Bothrops atrox is a widely distributed and medically important snake in Amazonia. Given that the reproductive and feeding biology of snakes varies geographically, we aimed to characterize the natural history of individuals from the central and southwestern portions of the biome. We analyzed museum-preserved specimens collected in the region between the metropolitan areas of the Brazilian cities of Manaus and Porto Velho. We took morphometric measurements and performed the analysis of gonads and digestive tracts of 109 individuals. Females attain sexual maturity with larger body sizes. Adults of the species show pronounced sexual dimorphism in body size, with females being larger. The reproductive cycle, especially in males, appears to be synchronized with regional rainfall, which markedly differed across the biome. The pitvipers had a generalist diet, consuming a wide range of prey such as centipedes, frogs, lizards, snakes and mammals. We provide the first record of predation of the snake Imantodes cenchoa (Dipsadidae) by B. atrox. There was an ontogenetic shift in the diet: smaller individuals fed mainly on ectothermic prey (centipedes, frogs, lizards and snakes), while adults tended to incorporate endothermic prey (mammals) to their food repertoire.RESUMO A jararaca Bothrops atrox é uma serpente de ampla distribuição e de importância médica na Amazônia. Visto que a biologia reprodutiva e alimentar de serpentes varia geograficamente, nosso objetivo foi o de caracterizar a história natural de indivíduos provenientes das porções central e sudoeste do bioma no Brasil. Analisamos espécimes preservados coletados na área compreendida entre as regiões metropolitanas dos municípios brasileiros de Manaus e Porto Velho. Realizamos medidas morfométricas e analisamos as gônadas e o trato digestivo de 109 exemplares. Fêmeas apresentaram maturação sexual com tamanhos corporais maiores que os machos. Adultos apresentaram marcado dimorfismo sexual em tamanho, sendo que as fêmeas foram, em média, maiores que os machos. O ciclo reprodutivo, especialmente em machos, pareceu estar sincronizado com o regime regional de chuvas, que difere de outras partes do bioma. As serpentes apresentaram dieta generalista, tendo ingerido uma ampla gama de presas, como lacraias, anuros, lagartos, serpentes e mamíferos. Registramos, pela primeira vez, a predação da serpente Imantodes cenchoa (Dipsadidae) por B. atrox. Houve mudança ontogenética na dieta: indivíduos menores se alimentaram principalmente de presas ectotérmicas (lacraias, anuros, lagartos e serpentes) e adultos tenderam a incorporar itens endotérmicos (mamíferos) ao repertório alimentar.
  • Insights into the development of a juvenile harpy eagle’s hunting

    • Abstract: ABSTRACT The post-fledging period is of paramount importance for raptors, since this is when a juvenile develops its hunting skills and gains the abilities required in adulthood and independence through dispersal. Little is known however, about this stage in the lives of raptors such as harpy eagles, Harpia harpyja. Between March 2016 and July 2017, we recorded three predation attempts on groups of primates by a wild juvenile harpy eagle in southwestern Brazilian Amazonia, including the first predation of an adult squirrel monkey, Saimiri ustus. These sequential records give insights into the gradual development of hunting skills during the post-fledging period, similar to what has been reported for other birds of prey. We hypothesize that a link between developing flight skills, decreasing parental food provisioning and increasingly successful captures triggers adulthood and independence in harpy eagles.RESUMO O período pós-emplumagem é de suma importância para os rapinantes, pois é quando um jovem desenvolve a habilidade de caça necessária na idade adulta e a independência por meio da dispersão. Entretanto, pouco se sabe sobre esse estágio na vida de rapinantes como o gavião-real, Harpia harpyja. Entre março 2016 e julho 2017, três tentativas de predação sobre grupos de primatas por um gavião-real juvenil foram registradas no sudoeste da Amazônia brasileira, incluindo a primeira predação de um macaco-de-cheiro adulto, Saimiri ustus. Estes registros sequenciais indicam um desenvolvimento gradual da habilidade de caça ao longo do período de pós-emplumagem, de forma similar ao relatado para outros rapinantes. Hipotetizamos que a associação entre o desenvolvimento da habilidade de voo, diminuição do provisionamento pelos pais e aumento da taxa de capturas bem-sucedidas promove a maturidade e independência no gavião-real.
  • Description of immature stages of Ablabesmyia cordeiroi Neubern, 2013
           (Diptera: Chironomidae: Tanypodinae)

    • Abstract: ABSTRACT Abalesmyia cordeiroi Neubern was originally described based on adult males collected in the Amazon region; therefore, females and immatures of this species are unknown. In the present study, the pupal and larval stages of A. cordeiroi are described and illustrated. In addition, an amendment to the larval diagnosis of Ablabesmyia is provided.RESUMO Ablabesmyia cordeiroi Neubern foi descrita originalmente com base em machos coletados na região amazônica, portanto, a fêmea e os imaturos desta espécie são desconhecidos. No presente estudo, os estágios de pupa e larva de A. cordeiroi são descritos e ilustrados. Além disso, uma emenda à diagnose da larva de Ablabesmyia é fornecida.
  • Anuran diversity in urban and rural zones of the Itacoatiara municipality,
           central Amazonia, Brazil

    • Abstract: ABSTRACT Few studies in the Amazon region have evaluated anuran diversity in urban forest fragments or in areas with differing degrees of anthropogenic impact. We determined the composition and abundance of the anurofauna in urban and rural sites within the municipality of Itacoatiara in central Amazonia, Brazil. Specimens were sampled from January 2012 to May 2013 in 10 urban sites and five rural sites. A total of 1,538 anurans (930 in rural sites and 608 in urban sites) were recorded, belonging to 29 species in five families. Species richness was higher in rural sites, with 10 exclusive species. All species found in urban sites were also found in rural sites, however, species abundance varied considerably between the habitats. Sampling- and individual-based rarefaction curves showed a tendency toward stabilization of species richness only in the urban sites. We concluded that the anuran assemblages in the urban sites are depauperate due to the absence of many species associated to pristine terra firme or várzea and igapó forests. Habitat loss and quality degradation in urban landscapes are the main factors threatening amphibian diversity. The anuran assemblages in our study areas were similar to those recorded in other Amazonian habitats. Conservation measures involving anurans in this region should consider the preservation of habitat mosaics, including both pristine terra firme, várzea and igapó forests.RESUMO Poucos estudos avaliaram a diversidade de anuros em fragmentos florestais urbanos ou em áreas com diferentes graus de impacto antrópico na Amazônia. Neste estudo foi determinada a composição e abundância de anuros em áreas urbanas e rurais no município de Itacoatiara, na Amazônia central, Brasil. Anuros foram amostrados entre janeiro de 2012 e maio de 2013 em 10 locais na área urbana e cinco na área rural. Um total de 1.538 indivíduos (930 na área rural e 608 na área urbana) foram registrados, compreendendo 29 espécies e cinco famílias. A área rural apresentou maior riqueza de espécies, com 10 espécies exclusivas. Todas as espécies identificadas na área urbana também foram encontradas na área rural, mas a abundância das espécies entre ambas áreas variou consideravelmente. Curvas de rarefação por amostragem e por número de indivíduos tenderam à estabilização na riqueza de espécies somente na área urbana. Concluímos que a comunidade de anuros na área urbana está empobrecida devido à ausência de muitas espécies associadas à ambientes inalterados de florestas de terra firme, várzea e igapó. A degradação da qualidade e a perda de habitat nas paisagens urbanas são os principais fatores que ameaçam a diversidade de anfíbios. A comunidade de anuros registrada neste estudo foi similar às de outros habitats na Amazônia. Medidas de conservação envolvendo anuros nesta região devem considerar a preservação de um mosaico de habitats que inclua áreas naturais de floresta de terra firme, várzea e igapó.
  • Record of the rare Caribbean mud eel, Pythonichthys sanguineus
           (Heterenchelyidae, Anguilliformes), in the region of the Amazon Reef

    • Abstract: ABSTRACT As they spend most of their time buried in the substrate and are not a fishery resource, heterenchelyids are seldom seen. These eels are characterized by their greatly reduced eyes, which are covered by semi-transparent skin, the absence of a pectoral fin or lateral line, and no pores on the head or body. Pythonichthys sanguineus is a particularly poorly-known species, with only eight scientific records from Cuba, Puerto Rico, Colombia, Venezuela, Guyana, and Suriname. The present study is based on six adult specimens of P. sanguineus captured by vessels of the shrimp trawling fleet along the northern Brazilian coast, in the vicinity of the Amazon Reef. We provide meristic, morphometric and DNA barcoding data. These findings provide insights into the distribution of the species off the northern Brazilian coast and contribute to the discussion about the southern limit of the Greater Caribbean fauna.RESUMO Heterenchelídeos passam a maior parte do tempo enterrados no substrato e raramente são vistos, não representando recursos pesqueiros importantes. Essas enguias são caracterizadas por seus olhos muito reduzidos e cobertos por pele semi-transparente, ausência de nadadeiras peitorais ou linha lateral, e ausência de poros na cabeça ou no corpo. Pythonichthys sanguineus é uma espécie particularmente pouco conhecida, com apenas oito registros em coleção zoológica para Cuba, Porto Rico, Colômbia, Venezuela, Guiana e Suriname. O presente estudo é baseado em seis espécimes adultos de P. sanguineus capturados pela frota industrial de arrasto de camarão-rosa na costa norte do Brasil, ao largo dos Recifes da Amazônia. Apresentamos dados merísticos, morfométricos e de DNA barcoding dos exemplares examinados. O registro fornece informações importantes sobre a distribuição da espécie na costa norte do Brasil, e contribui para a discussão sobre o limite sul da fauna do Grande Caribe.
  • Orthomene (Menispermaceae) in the Brazilian Amazon

    • Abstract: ABSTRACT Orthomene comprises four species distributed from Central to South America, of which three occur in phytogeographic domains of Brazil. In Brazil, Amazonia is the main center of diversity for the genus. This work is a taxonomic treatment of Orthomene in Brazil and involved analyzing field collections (between January 2017 and July 2018), types and botanical specimens from 32 national and foreign herbaria. The three species in the study area are Orthomene hirsuta,Orthomene prancei and Orthomene schomburgkii. The latter is the most common and widely distributed species of the genus in the country. An identification key, descriptions, illustrations, distribution data, and additional comments for each species are provided.RESUMO Orthomene possui quatro espécies, distribuídas desde a América Central até a América do Sul, sendo que três ocorrem nos domínios fitogeográficos brasileiros. No Brasil, a Amazônia brasileira é considerada o principal centro de diversidade do gênero. O tratamento taxonômico envolveu a análise de material coletado (entre janeiro de 2017 e julho de 2018), tipos e amostras dos espécimes de Orthomene depositados em 32 herbários nacionais e estrangeiros. O gênero está representado na área de estudo por três espécies: Orthomene hirsuta,Orthomene prancei e Orthomene schomburgkii, sendo esta última a mais comum e amplamente distribuída nas regiões brasileiras de sua ocorrência. São apresentadas uma chave de identificação, descrições e ilustrações das espécies, bem como dados adicionais sobre distribuição geográfica e comentários sobre as mesmas.
  • Evaluation of antimutagenic and cytotoxic activity of skin secretion
           extract of Rhinella marina and Rhaebo guttatus (Anura, Bufonidae)

    • Abstract: ABSTRACT The skin secretion from toads of the Bufonidae family has great potential in the search for new active compounds to be used as drug candidates in treating some diseases, among them cancer. In this context, this study aimed to evaluate the cytotoxic and antimutagenic activity of the parotoid gland secretion extracts of Rhinella marina and Rhaebo guttatus, as well as biochemically analyze transaminases and serum creatinine for liver and renal damage, respectively. Cytotoxicity was performed by the colorimetric method based on MTT (3- [4, 5-dimethyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazolium bromide) with different concentrations of the extracts in Walker or splenic tumor cell cultures from rats and mice. The micronucleus test was performed with male Swiss mice treated orally with the extracts for 15 days, and then intraperitoneally with N-ethyl-N-nitrosurea (50 mg kg-1). Micronucleated polychromatic erythrocytes (MNPCE) were evaluated in bone marrow. The extracts showed cytotoxic activity in the evaluated cells. There was a significant reduction in the frequency of MNPCE (R. marina = 56% and R. guttatus = 75%, p < 0.001), indicating antimutagenic potential of the extracts. The groups treated only with extract showed an increase in MNPCE frequency, evidencing mutagenic potential. Biochemical analyzes showed no significant difference between treatments. Thus, under our experimental conditions, the extracts of R. marina and R. guttatus skin secretions presented chemopreventive potential for cancer.RESUMO A secreção cutânea de anuros da família Bufonidae tem grande potencial na busca de novos compostos ativos para utilização como fármacos candidatos no tratamento de algumas doenças, entre elas o câncer. Neste contexto, este estudo teve como objetivo avaliar a atividade citotóxica e antimutagênica dos extratos da secreção da glândula parótida de Rhinella marina e Rhaebo guttatus, bem como a análise bioquímica de transaminases e creatinina séricas, para avaliar dano hepático e renal, respectivamente. A avaliação de citotoxicidade foi realizada pelo método colorimétrico baseado no MTT (3-[4, 5-dimethyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazolium bromide), com diferentes concentrações dos extratos em culturas de células do Tumor de Walker ou células esplênicas de rato e camundongo. O teste do micronúcleo foi realizado com camundongos Swiss machos que receberam tratamento oral com os extratos durante 15 dias, seguido de tratamento intraperitoneal com N-etil-N-nitrosuréia (50 mg kg-1). A frequência de eritrócitos policromáticos micronucleados (PCEMN) foi determinada em medula óssea. Os extratos apresentaram ação citotóxica nas células avaliadas. Houve uma redução significativa na frequência de PCEMN (R. marina = 56% e R. guttatus = 75%, p < 0,001), observando-se um potencial antimutagênico dos extratos. Os grupos tratados somente com os extratos apresentaram um aumento na frequência de PCEMNs, evidenciando um potencial mutagênico. As análises bioquímicas não apresentaram diferença significativa entre os tratamentos. Assim, nas condições experimentais testadas, as secreções cutâneas de R. marina e R. guttatus apresentaram potencial quimiopreventivo para câncer.
  • Effect of Alpinia zerumbet essential oil on the shelf life of tambaqui
           fillets during short-term refrigerator storage

    • Abstract: ABSTRACT We investigated the effect of Alpinia zerumbet essential oil on the quality and shelf life of tambaqui (Colossoma macropomum) fillets stored under refrigeration (10.0 ± 0.5 °C) for 14 days. The treatments were A. zerumbet essential oil at 0.75% v v-1 (AEO 0.75%), A. zerumbet essential oil at 1.5% v v-1 (AEO 1.5%) and a control (no essential oil). The sample quality and shelf life were determined by the total psychrotrophic count (TPC) and chemical parameters (pH, total volatile basic nitrogen, centesimal composition and thiobarbituric acid reactive substances - TBARS) at zero, seven and 14 days of storage time. The TPC decreased significantly (p < 0.05) with an A. zerumbetessential oil level of 1.5% until seven days of storage. The concentration of A. zerumbet essential oil at 0.75% resulted in lower pH, TBARS, and TVBN values in comparison with the other treatment and the control. Thus, A. zerumbet essential oil was efficient in extending the shelf life of refrigerated tambaqui fillets up to approximately seven days.RESUMO Investigamos o efeito do óleo essencial de Alpinia zerumbet sobre a qualidade e vida útil de filés de tambaqui (Colossoma macropomum) armazenados sob refrigeração (10,0 ± 0,5 °C) durante 14 dias. Os tratamentos foram óleo essencial de A. zerumbet (OEA) a 0,75% v v-1 (OEA 0,75%) e 1,5% v v 1 (OEA 1,5%), além de um controle (sem OEA). A qualidade e vida útil das amostras foram determinadas por contagem psicrotrófica total (CPT) e parâmetros químicos (pH, bases nitrogenadas voláteis totais, composição centesimal e substâncias reativas ao ácido tiobarbitúrico - SRATB), nos dias zero, sete e 14 de armazenamento. O TPC diminuiu significativamente (p < 0,05) com óleo essencial de A. zerumbet a 1,5% por até sete dias de armazenamento. O tratamento contendo OEA a 0,75% resultou em menores valores de pH, SRTAB e BNV-T em comparação ao outro tratamento e ao controle. Portanto, o óleo essencial de A. zerumbet foi eficiente para prolongar a vida útil do filé de tambaqui por aproximadamente sete dias.
  • First report of Myxobolus (Cnidaria: Myxozoa) spores in human
           feces in Brazil

    • Abstract: ABSTRACT Most species of Myxobolus (Cnidaria: Myxozoa) infect freshwater and marine fish, and cause sporozoosis. Passage of myxozoan parasites into human feces has been described occasionally. We examined fecal samples from 97 dwellers of a riverine community in Amazonas State (Brazil), which revealed Myxobolus sp. in 13 (13%) samples. The discovery probably does not represent true parasitism as the myxospores - most likely ingested through the consumption of infected fish - were eliminated unchanged after passing through the gastrointestinal tract. This discovery represents the first report of this myxosporean in human fecal samples in Brazil.RESUMO A maioria das espécies de Myxobolus (Cnidaria: Myxozoa) infecta principalmente peixes de água doce e marinhos, nos quais produz esporozoose. A passagem de parasitos mixozoários em fezes humanas tem sido ocasionalmente descrita. Nós examinamos amostras fecais de 97 moradores de uma comunidade ribeirinha no estado do Amazonas e identificamos Myxobolus sp. em 13 (13%) delas. O achado provavelmente não representa um parasitismo verdadeiro, uma vez que os mixosporos − mais provavelmente ingeridos ao consumir peixes infectados − foram eliminados inalterados após a passagem pelo trato gastrointestinal. O achado representa o primeiro relato deste mixosporídeo em amostras fecais humanas no Brasil.
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
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Fax: +00 44 (0)131 4513327
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