8 research outputs found

    Lessons learned from functional assessment of pluripotency-associated transcription factors during early embryogenesis and embryonic stem cells

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    Pluripotency-associated transcription factors (PATF) play significant roles during early embryogenesis and in embryonic stem (ES) cells, such as control of cell-cycle progression, modulation of cellular metabolism, and transcriptional control of differentiation-inducing factors. The review aims to describe the current understanding of how these PATFs contribute to the early embryo and the ES-cell phenotypes. By a selection of representative examples of such PATFs, their roles are described, and some interesting questions are presented concerning their activity in pluripotent cells which have yet to be addressed

    Use of grayscale histogram to assess testicular changes in ram caused by heat stress

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    Because it detects discrete changes in tissue density, ultrasound allows an early diagnosis of physiologic changes, especially when dealing with subclinical changes. aimed to evaluate the use of quantitative analysis of the gray scale of ultrasound images of ovine testicles as a method for early diagnosis of testicular changes caused by heat stress. Testicles from ten ovine were insulated and then evaluated regarding echogenicity, echotexture, anatomical measurements, and seminal characteristics. Echogenicity was the first variable to show changes during the insulation period, as well as the first one to show evidence of regeneration of those changes. There was a correlation (p 0.05) in echotexture. Testicular measurements were only altered (p < 0.05) after insulation; however, the structural integrity of the seminiferous tubules was not altered. Echogenicity is an efficient ultrasound parameter for the early diagnosis of a testicular degenerative process as well as for the early diagnosis of its regeneration

    Use of grayscale histogram to assess testicular changes in ram caused by heat stress

    Get PDF
    Because it detects discrete changes in tissue density, ultrasound allows an early diagnosis of physiologic changes, especially when dealing with subclinical changes. aimed to evaluate the use of quantitative analysis of the gray scale of ultrasound images of ovine testicles as a method for early diagnosis of testicular changes caused by heat stress. Testicles from ten ovine were insulated and then evaluated regarding echogenicity, echotexture, anatomical measurements, and seminal characteristics. Echogenicity was the first variable to show changes during the insulation period, as well as the first one to show evidence of regeneration of those changes. There was a correlation (p &lt; 0.05) between echogenicity and sperm vigor, motility, and mass sperm motility, as well as a correlation (p &lt; 0.05) between echotexture and motility. Echogenicity, motility, vigor, and mass sperm motility decreased (p &lt; 0.05) within four days of testicular insulation, and there was no change (p &gt; 0.05) in echotexture. Testicular measurements were only altered (p &lt; 0.05) after insulation; however, the structural integrity of the seminiferous tubules was not altered. Echogenicity is an efficient ultrasound parameter for the early diagnosis of a testicular degenerative process as well as for the early diagnosis of its regeneration.Because it detects discrete changes in tissue density, ultrasound allows an early diagnosis of physiologic changes, especially when dealing with sub-clinical changes. The study aimed to evaluate the use of quantitative analysis of the grayscale of ultrasound images of ovine testicles as a method for early diagnosis of testicular changes caused by heat stress. Testicles from ten rams were insulated and then evaluated regarding echogenicity, echotexture, anatomical measurements, and seminal characteristics. Echogenicity was the first variable to show changes during the insulation period, as well as the first one to show evidence of regeneration of those changes. There was a correlation (p &lt; 0.05) between echogenicity and sperm vigor, sperm motility, and mass sperm motility, as well as a correlation (p &lt; 0.05) between echotexture and motility. Echogenicity, sperm motility, vigor, and mass sperm motility decreased (p &lt; 0.05) within four days of testicular insulation, and there was no change (p &gt; 0.05) in echotexture. Testicular measurements were only altered (p &lt; 0.05) after insulation. Echogenicity is an efficient ultrasound parameter for the early diagnosis of a testicular degenerative process as well as for the early diagnosis of its regeneration

    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

    Get PDF

    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

    Ser e tornar-se professor: práticas educativas no contexto escolar

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