1,156 research outputs found

    THE WORLD MARKET FOR SOYBEANS: PRICE TRANSMISSION INTO BRAZIL AND EFFECTS FROM THE TIMING OF CROP AND TRADE

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    This paper investigates the price transmission in the world market for soybeans using time series econometrics models. The theoretical model developed by Mundlack and Larson (1992) is based on the Law of the One Price, which assumes price equalization across all local markets in the long run and allows for deviations in the short run. The international market was characterized by three relevant soybean prices: Rotterdam Port, Argentina and the United States. The paper estimates the elasticity of transmission of these prices into soybean prices in Brazil. There were carried causality and cointegration tests in order to identify whether there is significant long-term relationship among these variables. There was also calculated the impulse-response function and forecast error variance decomposition to analyze the transmission of variations in the international prices over Brazilian prices. An exogeneity test was also carried out so as to check whether the variables respond to short term deviations from equilibrium values. Results validated the Law of the One Price in the long run. In line with many studies, this paper showed that Brazil and Argentina can be seen as price takers as long as the speed of their adjustment to shocks is faster than in the United States, the latter being a price maker. An interesting conclusion was reached when the pattern of the impulse response functions was compared to the timing of crop and trade in Brazil, Argentina and the United States. These seasonal differences may help explaining the pattern of the response of Brazilian prices to shocks in the international market, especially that the response from shocks in the United States is opposite to the response from shocks in Argentina because harvest in the two hemispheres occurs in different periods. In addition, the one-month lag between Brazilian and Argentine harvests may contribute to explain a turning point in the impulse-response function that occurs one month after the shock.

    Sampling design may obscure species–area relationships in landscape-scale field studies

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    We investigated 1) the role of area per se in explaining anuran species richness on reservoir forest islands, after controlling for several confounding factors. We also assessed 2) how sampling design affects the inferential power of island species–area relationships (ISARs) aiming to 3) provide guidelines to yield reliable estimates of area-induced species losses in patchy systems. We surveyed anurans with autonomous recording units at 151 plots located on 74 islands and four continuous forest sites at the Balbina Hydroelectric Reservoir landscape, central Brazilian Amazonia. We applied semi-log ISAR models to assess the effect of sampling design on the fit and slope of species–area curves. To do so, we subsampled our surveyed islands following both a 1) stratified and 2) non-stratified random selection of 5, 10, 15, 20 and 25 islands covering 1) the full range in island size (0.45–1699 ha) and 2) only islands smaller than 100 ha, respectively. We also compiled 25 datasets from the literature to assess the generality of our findings. Island size explained ca half of the variation in species richness. The fit and slope of species–area curves were affected mainly by the range in island size considered, and to a very small extent by the number of islands surveyed. In our literature review, all datasets covering a range of patch sizes larger than 300 ha yielded a positive ISAR, whereas the number of patches alone did not affect the detection of ISARs. We conclude that 1) area per se plays a major role in explaining anuran species richness on forest islands within an Amazonian anthropogenic archipelago; 2) the inferential power of island species–area relationships is severely degraded by sub-optimal sampling designs; 3) at least 10 habitat patches spanning three orders of magnitude in size should be surveyed to yield reliable species–area estimates in patchy systems

    Patch-scale biodiversity retention in fragmented landscapes:Reconciling the habitat amount hypothesis with the island biogeography theory

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    Aim: To test whether the species richness of understorey insectivorous birds on forest islands induced by a major hydroelectric dam is best explained by either the island biogeography theory (IBT) or the habitat amount hypothesis (HAH). Given the low dispersal ability of the focal species group and the hostile water matrix, we predict that the species richness will be predominantly driven by an island effect as posited by the IBT, rather than a sample area effect as posited by the HAH. Location: Forest islands within the Balbina Hydroelectric Reservoir, central Brazilian Amazonia. Taxon: Birds. Methods: We mist-netted birds at 33 forest islands (0.63–1,699 ha), totalling 874 individuals of 59 species. The size of the local landscape used to calculate the habitat amount was determined by a multi-scale analysis in which buffers around mist-net lines ranged from 50 to 2,000 m. We applied four tests to examine whether the species richness on forest islands is predominantly driven by either an island effect (island size) or a sample area effect (habitat amount). Results: From the four tests applied, one was consistent with an island effect, two were regarded as inappropriate to test the HAH, and one could not be adequately addressed due to island size being highly correlated with habitat amount in the local landscape (200-m buffer). Main conclusions: Some of the proposed ways of testing the HAH may lead to misleading conclusions. The relative importance of island size in determining the species richness of understorey insectivorous birds on forest islands is higher than that of surrounding habitat amount, thereby providing stronger support for IBT. We propose a conceptual framework, based on the degree of matrix permeability and species dispersal ability, to determine to what extent a patch- or landscape-centric worldview in landscape ecology provides the most appropriate framework to assess the effects of habitat fragmentation on biodiversity

    Analysis of errors in verbal fluency tasks in patients with chronic schizophrenia

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    Background and Objectives: Even if verbal fluency deficits have been described in Schizophrenia, error pattern in this test has not been analyzed in detail in the literature. The pattern analysis of such errors could contribute to the understanding of the factors that influence poor task performance in schizophrenia. In this study we analyzed the intrusion and perseveration errors in verbal fluency tasks in patients with chronic schizophrenia. Methods: 87 patients diagnosed with Chronic Schizophrenia and 87 healthy controls were included in this investigation and were assessed with four Phonological and Semantic Verbal Fluency tasks. Results The results of this study showed that at least half of schizophrenic patients produced perseverative errors on verbal fluency and about made intrusion errors. The severity of negative symptoms, the severity of Formal Thought Disorder and pharmacological variables were significant moderators to errors in Verbal Fluency performance. Conclusions Errors in Verbal Fluency can be explained by the interaction of different variables in patients with schizophrenia. Schizophrenia is a psychological pathology with great phenomenological complexity and its particularities can only be explained by the consideration of the multiple factors involved in its manifestation.Fil: Galaverna, Flavia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva. Fundación Favaloro. Instituto de Neurociencia Cognitiva; ArgentinaFil: Bueno, Adrián Marcelo. Universidad Nacional de Córdoba. Facultad de Psicología; ArgentinaFil: Morra, Carlos A.. Prof. León S. Morra Sanitarium; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Roca, María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva. Fundación Favaloro. Instituto de Neurociencia Cognitiva; ArgentinaFil: Torralva, Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva. Fundación Favaloro. Instituto de Neurociencia Cognitiva; Argentin

    Remodeling of the m6A RNA landscape in the conversion of acute lymphoblastic leukemia cells to macrophages

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    We thank CERCA Programme/Generalitat de Catalunya for institutional support. This work was supported by the Health Department PERIS-project no. SLT/002/16/00374 and AGAUR-projects no. 2017SGR1080 of the Catalan Government (Generalitat de Catalunya); Ministerio de Ciencia e Innovación (MCI), Agencia Estatal de Investigación (AEI) and European Regional Development Fund (ERDF) project no. RTI2018-094049-B-I00; the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant agreement No. 743168); the Varda and Boaz Dotan Research Center in Hemato-oncology affiliated to the Tel Aviv University; the Cellex Foundation; and “la Caixa” Banking Foundation (LCF/PR/GN18/51140001). ME is an ICREA Research Professor.Peer Reviewed"Article signat per 12 autors/es: Alberto Bueno-Costa, David Piñeyro, Carlos A. García-Prieto, Vanessa Ortiz-Barahona, Laura Martinez-Verbo, Natalie A. Webster, Byron Andrews, Nitzan Kol, Chen Avrahami, Sharon Moshitch-Moshkovitz, Gideon Rechavi & Manel Esteller"Postprint (published version

    Versatile Graphene-Based Platform for Robust Nanobiohybrid Interfaces

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    Technologically useful and robust graphene-based interfaces for devices require the introduction of highly selective, stable, and covalently bonded functionalities on the graphene surface, whilst essentially retaining the electronic properties of the pristine layer. This work demonstrates that highly controlled, ultrahigh vacuum covalent chemical functionalization of graphene sheets with a thiol-terminated molecule provides a robust and tunable platform for the development of hybrid nanostructures in different environments. We employ this facile strategy to covalently couple two representative systems of broad interest: metal nanoparticles, via S-metal bonds, and thiol-modified DNA aptamers, via disulfide bridges. Both systems, which have been characterized by a multi-technique approach, remain firmly anchored to the graphene surface even after several washing cycles. Atomic force microscopy images demonstrate that the conjugated aptamer retains the functionality required to recognize a target protein. This methodology opens a new route to the integration of high-quality graphene layers into diverse technological platforms, including plasmonics, optoelectronics, or biosensing. With respect to the latter, the viability of a thiol-functionalized chemical vapor deposition graphene-based solution-gated field-effect transistor array was assessed

    Insect repellents: recommendations for use in children

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    OBJETIVO: Apresentar uma revisão bibliográfica sobre o uso de repelentes de insetos em crianças, com ênfase especial na proteção contra mosquitos. FONTES DE DADOS: Realizou-se uma pesquisa bibliográfica nas bases de dados Pubmed e Lilacs, cujos artigos incluíam produtos comercialmente disponíveis no Brasil. Foram selecionados artigos publicados nos últimos dez anos em língua inglesa ou portuguesa, referentes a crianças, obtidos com as seguintes palavras-chave: "insect repellents", "children", "mosquitoes", "N,N-dietil-metatoluamida (DEET)". SÍNTESE DOS DADOS: Entre os repelentes tópicos, DEET, icaridina e óleo natural de eucalipto-limão apresentam, em concentrações adequadas, perfil de segurança favorável e são eficazes na prevenção de picadas de mosquitos em crianças e adultos. Em geral, são indicados para crianças acima de dois anos de idade. Medidas físicas são fundamentais para proteger lactentes jovens, especialmente menores de seis meses, com destaque para o uso de telas com permetrina. CONCLUSÕES: Os mosquitos são vetores de doenças infectoparasitárias que acometem, anualmente, milhões de pessoas no mundo e causam milhares de mortes. O combate aos mosquitos inclui medidas ambientais e de proteção individual. O uso de repelentes tópicos para proteção individual da criança exige cuidados específicos e conhecimento quanto ao produto ideal para cada idade, especialmente quando consideradas sua eficácia e segurança.OBJECTIVE: To present a literature review about the use of insect repellents on children, highlighting the protection against mosquitoes. DATA SOURCES: Pubmed and Lilacs databases were searched for articles in English and Portuguese published in the last ten years with the following key-words: "insect repellents", "children", "mosquitoes", "N,N-dietil-metatoluamida (DEET)". DATA SYNTHESIS: Concerning topical repellents, DEET, icaridine and natural oil of lemon eucalyptus are effective to prevent mosquito bites in children and adults and have favorable safety profile when used in appropriate concentration. They are generally recommended for children older than two years-old. Physical barriers are essential for infant protection, especially if they are six months old or less, with special interest in the permethrin-treated nets. CONCLUSIONS: Mosquitoes are vectors of a variety of infectious and parasitic diseases which annually affect millions of people and cause thousands of deaths worldwide. The combat to mosquitoes includes individual and environmental measures. Topic repellents for children's individual protection demand specific handling attention and knowledge about the ideal product for each age, especially regarding their efficacy and safety

    Effects of Sulpiride on True and False Memories of Thematically Related Pictures and Associated Words in Healthy Volunteers

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    Episodic memory, working memory, emotional memory, and attention are subject to dopaminergic modulation. However, the potential role of dopamine on the generation of false memories is unknown. This study defined the role of the dopamine D-2 receptor on true and false recognition memories. Twenty-four young, healthy volunteers ingested a single dose of placebo or 400 mg oral sulpiride, a dopamine D-2-receptor antagonist, just before starting the recognition memory task in a randomized, double-blind, and placebo-controlled trial. The sulpiride group presented more false recognitions during visual and verbal processing than the placebo group, although both groups had the same indices of true memory. These findings demonstrate that dopamine D-2 receptors blockade in healthy volunteers can specifically increase the rate of false recognitions. The findings fit well the two-process view of causes of false memories, the activation/monitoring failures model.Univ Fed Sao Paulo, Dept Psychobiol, Sao Paulo, BrazilAssociacao Fundo Incent Pesquisa, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Physiol, Sao Paulo, BrazilUniv Fed Sao Paulo, Dept Psychobiol, Sao Paulo, BrazilWeb of Scienc
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