51 research outputs found

    SUBSTITUIÇÃO DOS GRÃOS SECOS DE MILHO PELA SILAGEM DE GRÃOS ÚMIDOS DE MILHO PARA VACAS DA RAÇA HOLANDESA EM LACTAÇÃO

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    RESUMO: Com o objetivo de avaliar os efeitos da substituição dos grãos secos de milho (GSM) pela silagem de grãos úmidos de milho (SGUM) sobre a produção e composição do leite, foram utilizadas cinco vacas da raça Holandesas, primíparas com média de 112 dias pós-parto, confinadas em Tie Stall, por 70 dias. Utilizou-se cinco rações de acordo com o NRC para 17,5% PB (MS) e 2,4 Mcal EM/kg MS, na relação 40:60 de volumoso e concentrado contendo farelo de soja, silagem de cana de açúcar e feno e níveis de substituição dos GSM pela SGUM nos tratamentos: 1) 0%; 2) 25%; 3) 50%; 4) 75% e 5) 100%. A produção de leite e o consumo de matéria seca (CMS) foram registrados diariamente. Os animais foram ordenhados diariamente 6:00 e 18:00 h, sendo as amostras de leite coletadas nas ordenhas consecutivas de cada fase experimental de 14 dias (quatro dias de coleta). O delineamento experimental utilizado foi o Quadrado Latino 5x5 e os dados analisados pelo programa estatístico SAS. O peso corporal (508 kg), produção de leite (23,6 kg), produção de leite corrigida (22,7 kg), CMS (17,13 kg), não apresentaram diferença significativas, porém os consumos de fibra em detergente neutro (6,67 kg), e em detergente ácido (3,39 kg), eficiência alimentar para produção de leite (1,41 kg leite/dia) o nitrogênio uréico (17,67 mg/dL) apresentaram diferença, indicando desta forma que a SGUM é mais eficiente que os GSM na dieta de vacas em lactação por não  alterar a produção e composição do leite

    Nitrogen fertilization on sorghum intercropped with grass in a no‑tillage system

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    O objetivo deste trabalho foi avaliar o efeito do manejo da adubação nitrogenada sobre a cultura do sorgo granífero, cultivado solteiro e em consócio com capim-marandu e capim-mombaça, e determinar a produtividade de matéria seca das forrageiras, nos anos agrícolas 2003/2004 e 2004/2005, em plantio direto. Foi utilizado o delineamento experimental em blocos ao acaso, em arranjo fatorial 3x5, com quatro repetições. Os tratamentos consistiram de três sistemas de cultivo de sorgo granífero (solteiro e consorciado com capim-marandu ou capim-mombaça, na linha de semeadura) e cinco manejos de adubação nitrogenada: 30–70; 70–30; 50–50; 100–0; e 0–100 kg ha-1 de N, quantidades aplicadas na semeadura e na cobertura, respectivamente. O cultivo consorciado não afetou a nutrição nem a produtividade de grãos de sorgo. Apenas no primeiro ano de cultivo, o parcelamento 50–50 kg ha-1 de N proporcionou maior produtividade de grãos. O manejo da palhada interferiu no estabelecimento do sorgo no segundo ano de cultivo, e diminuiu a produtividade de grãos. As maiores doses de N aplicadas em cobertura elevaram a produtividade de matéria seca do capim-marandu e, as aplicadas em semeadura, a elevaram no capim-mombaça.The objective of this work was to evaluate the effect of nitrogen fertilization management on single and intercropped sorghum with Marandu and Mombaça grasses, and to determine the forage dry weight yield in the 2003/2004 and 2004/2005, in a no-tillage system. The experimental design was in randomized block, in a 3x5 factorial arrangement, with four replicates. The treatments consisted of three sorghum cropping systems (single and intercropped with Marandu and Mombaça grasses in the rows) and five nitrogen fertilizer managements: 30–70; 70–30; 50–50; 100–0; and 0–100 kg ha-1 of N, applied at sowing and topdressing, respectively. Intercropping did not affect sorghum nutrition nor grain yield. Only in the first growth season, the 50–50 kg ha-1 of N splitting increased grain yield. Straw management interfered in sorghum establishment during the second growth season and decreased grain yield. The highest rates of N topdressing increased forage dry weight yield of Marandu grass and, applied at sowing, N highest rates increased this attribute in Mombaça grass

    Nutrition and yield behavior of sorghum hybrids with contrasting cycles intercropped with Marandu grass

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    O objetivo deste trabalho foi avaliar o efeito do consórcio com capim-marandu (Urochloa brizantha) na nutrição e produtividade de híbridos de sorgo granífero de ciclos contrastantes, em sistema plantio direto. Utilizou-se o delineamento experimental de blocos ao acaso, em arranjo fatorial 2x2, com seis repetições. Os tratamentos consistiram de dois híbridos de sorgo granífero de ciclos contrastantes (P8118, ciclo médio; e P8419, ciclo precoce) e dois sistemas de cultivo (monocultivo e consórcio com capim-marandu na linha de semeadura), com semeadura no início de dezembro. Avaliou-se a nutrição, as características agronômicas, os componentes da produção e a produtividade de matéria seca e grãos da cultura do sorgo. Com exceção do potássio e do enxofre, os teores foliares dos demais nutrientes foram adequados à cultura do sorgo granífero, em todos os tratamentos. O híbrido P8118 apresentou a maior produtividade de grãos e, após o consórcio, contribuiu para a maior produtividade de matéria seca da forragem de capim-marandu, no corte realizado em outubro. O cultivo consorciado com capim-marandu não afeta a nutrição e a produtividade de matéria seca e de grãos de sorgo, em comparação ao monocultivo, independentemente do ciclo do híbrido utilizado.The objective of this work was to evaluate the effect of the intercropping with Marandu grass on the nutrition and yield of sorghum hybrids with contrasting-cycle, in no-tillage system. It was used a randomized block experimental design in a factorial arrangement (2x2), with six replicates. The treatments consisted of two sorghum hybrids with contrasting cycles (P8118, medium cycle; and P8419, early cycle) and two crop systems (single and intercropped with Marandu grass in the seed row), with the seeding done in the early December. Nutrition, agronomic traits, production components, and dry matter and grain yields of the sorghum hybrids were evaluated. Except for potassium and sulphur, the leaf contents of the other nutrients were appropriate in all treatments for sorghum cropping. The hybrid P8118 had the highest grain yield and, after the intercropping, it contributed for the highest forage dry matter yield of Marandu grass in the cut performed in October. The intercropping of contrasting-cycle sorghum hybrids and Marandu grass does not affect sorghum nutrition, and dry matter and grain yields, in comparison with the single cropping, irrespectively of the hybrid cycle

    The Trypanosoma cruzi pleiotropic protein P21 orchestrates the intracellular retention and in-vivo parasitism control of virulent Y strain parasites

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    P21 is a protein secreted by all forms of Trypanosoma cruzi (T. cruzi) with recognized biological activities determined in studies using the recombinant form of the protein. In our recent study, we found that the ablation of P21 gene decreased Y strain axenic epimastigotes multiplication and increased intracellular replication of amastigotes in HeLa cells infected with metacyclic trypomastigotes. In the present study, we investigated the effect of P21 in vitro using C2C12 cell lines infected with tissue culture-derived trypomastigotes (TCT) of wild-type and P21 knockout (TcP21−/−) Y strain, and in vivo using an experimental model of T. cruzi infection in BALB/c mice. Our in-vitro results showed a significant decrease in the host cell invasion rate by TcP21−/− parasites as measured by Giemsa staining and cell count in bright light microscope. Quantitative polymerase chain reaction (qPCR) analysis showed that TcP21−/− parasites multiplied intracellularly to a higher extent than the scrambled parasites at 72h post-infection. In addition, we observed a higher egress of TcP21−/− trypomastigotes from C2C12 cells at 144h and 168h post-infection. Mice infected with Y strain TcP21−/− trypomastigotes displayed higher systemic parasitemia, heart tissue parasite burden, and several histopathological alterations in heart tissues compared to control animals infected with scrambled parasites. Therewith, we propose that P21 is important in the host–pathogen interaction during invasion, cell multiplication, and egress, and may be part of the mechanism that controls parasitism and promotes chronic infection without patent systemic parasitemia

    Adubação nitrogenada de sorgo granífero consorciado com capim em sistema de plantio direto

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    O objetivo deste trabalho foi avaliar o efeito do manejo da adubação nitrogenada sobre a cultura do sorgo granífero, cultivado solteiro e em consócio com capim-marandu e capim-mombaça, e determinar a produtividade de matéria seca das forrageiras, nos anos agrícolas 2003/2004 e 2004/2005, em plantio direto. Foi utilizado o delineamento experimental em blocos ao acaso, em arranjo fatorial 3x5, com quatro repetições. Os tratamentos consistiram de três sistemas de cultivo de sorgo granífero (solteiro e consorciado com capim-marandu ou capim-mombaça, na linha de semeadura) e cinco manejos de adubação nitrogenada: 30-70; 70-30; 50-50; 100-0; e 0-100 kg ha-1 de N, quantidades aplicadas na semeadura e na cobertura, respectivamente. O cultivo consorciado não afetou a nutrição nem a produtividade de grãos de sorgo. Apenas no primeiro ano de cultivo, o parcelamento 50-50 kg ha-1 de N proporcionou maior produtividade de grãos. O manejo da palhada interferiu no estabelecimento do sorgo no segundo ano de cultivo, e diminuiu a produtividade de grãos. As maiores doses de N aplicadas em cobertura elevaram a produtividade de matéria seca do capim-marandu e, as aplicadas em semeadura, a elevaram no capim-mombaça

    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

    Pervasive gaps in Amazonian ecological research

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    Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

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    The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

    Pervasive gaps in Amazonian ecological research

    Get PDF
    Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost
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