2,921 research outputs found

    Individual differences and knockout in zebrafish reveal similar cognitive effects of BDNF between teleosts and mammals

    Get PDF
    The remarkable similarities in cognitive performance between teleosts and mammals suggest that the underlying cognitive mechanisms might also be similar in these two groups. We tested this hypothesis by assessing the effects of the brain-derived neurotrophic factor (BDNF), which is critical for mammalian cognitive functioning, on fish's cognitive abilities. We found that individual differences in zebrafish's learning abilities were positively correlated with bdnf expression. Moreover, a CRISPR/Cas9 mutant zebrafish line that lacks the BDNF gene (bdnf(-/-)) showed remarkable learning deficits. Half of the mutants failed a colour discrimination task, whereas the remaining mutants learned the task slowly, taking three times longer than control bdnf(+/+) zebrafish. The mutants also took twice as long to acquire a T-maze task compared to control zebrafish and showed difficulties exerting inhibitory control. An analysis of habituation learning revealed that cognitive impairment in mutants emerges early during development, but could be rescued with a synthetic BDNF agonist. Overall, our study indicates that BDNF has a similar activational effect on cognitive performance in zebrafish and in mammals, supporting the idea that its function is conserved in vertebrates

    VIP: An Experiment to Search for a Violation of the Pauli Exclusion Principle

    Full text link
    The Pauli Exclusion Principle is a basic principle of Quantum Mechanics, and its validity has never been seriously challenged. However, given its fundamental standing, it is very important to check it as thoroughly as possible. Here we describe the VIP (VIolation of the Pauli exclusion principle) experiment, an improved version of the Ramberg and Snow experiment (E. Ramberg and G. Snow, {\it Phys. Lett. B} {\bf 238}, 438 (1990)); VIP has just completed the installation at the Gran Sasso underground laboratory, and aims to test the Pauli Exclusion Principle for electrons with unprecedented accuracy, down to β2/210301031\beta^2/2 \approx 10^{-30} - 10^{-31}. We report preliminary experimental results and briefly discuss some of the implications of a possible violation.Comment: Plenary talk presented by E. Milotti at Meson 2006, Cracow, 9-13 June 200

    New experimental limit on Pauli Exclusion Principle violation by electrons (the VIP experiment)

    Full text link
    The Pauli Exclusion Principle is one of the basic principles of modern physics and is at the very basis of our understanding of matter: thus it is fundamental importance to test the limits of its validity. Here we present the VIP (Violation of the Pauli Exclusion Principle) experiment, where we search for anomalous X-rays emitted by copper atoms in a conductor: any detection of these anomalous X-rays would mark a Pauli-forbidden transition. ] VIP is currently taking data at the Gran Sasso underground laboratories, and its scientific goal is to improve by at least four orders of magnitude the previous limit on the probability of Pauli violating transitions, bringing it into the 10**-29 - 10**-30 region. First experimental results, together with future plans, are presented.Comment: To appear in proceedings of the XLVI International Winter Meeting on Nuclear Physics, Bormio, Italy, January 20-26, 200

    Tamanhos e posições de explantes e volumes de meio de cultivo na multiplicação de ipeca. (Psychotria ipecacuanha (Brot.) Stokes) in vitro.

    Get PDF
    No presente trabalho, avaliaram-se o efeito do tamanho e posição de explantes na planta de ipeca e diferentes volumes de meio de cultivo na multiplicação ?in vitro? de Psychotria ipecacuanha (Brot.) Stokes. O experimento que avaliou o efeito dos diferentes tamanhos e posições de explantes foi conduzido em tubos de ensaio de 25x150 mm, contendo 20 mL de meio de cultivo por tubo, sendo avaliados os tamanhos de 0,5; 1,0 e 1,5 cm nas posições basal, mediana e apical. No segundo experimento, utilizaram-se frascos nos quais os tratamentos consistiam nos volumes de 10, 20, 30 e 40 mL de meio de cultivo por frasco. O meio de cultivo utilizado nos dois experimentos foi o MS (MURASHIGE e SKOOG, 1962) acrescido de 1,5 mg. L-1 de BAP (6-benzilaminopurina). A posição do segmento internodal não influenciou o desenvolvimento vegetativo; os tamanhos de 1,0 e 1,5 cm apresentaram maior número de brotações que os segmentos com 0,5 cm. No experimento com diferentes volumes de meio de cultivo, observou-se que 30 e 40 mL foram significativamente melhores na indução de brotações adventícias nessa espécie

    The VIP Experiment

    Get PDF
    The Pauli Exclusion Principle (PEP) is a basic principle of Quantum Mechanics, and its validity has never been seriously challenged. However, given its importance, it is very important to check it as thoroughly as possible. Here we describe the VIP (Violation of PEP) experiment, an improved version of the Ramberg and Snow experiment (Ramberg and Snow, Phys. Lett. B238 (1990) 438); VIP shall be performed at the Gran Sasso underground laboratories, and aims to test the Pauli Exclusion Principle for electrons with unprecedented accuracy, down to β221030\frac{\beta^2}{2} \sim 10^{-30}Comment: 7 pages, 5 figures, PDF only, presented by Edoardo Milotti to the conference "Quantum Theory: reconsideration of foundations-3", Vaxjo (Sweden), June, 6-11 200

    New experimental limit on Pauli Exclusion Principle violation by electrons (the VIP experiment)

    Get PDF
    The Pauli exclusion principle (PEP) represents one of the basic principles of modern physics and, even if there are no compelling reasons to doubt its validity, it still spurs a lively debate, because an intuitive, elementary explanation is still missing, and because of its unique stand among the basic symmetries of physics. A new limit on the probability that PEP is violated by electrons was estabilished by the VIP (VIolation of the Pauli exclusion principle) Collaboration, using the method of searching for PEP forbidden atomic transitions in copper. The preliminary value, {1/2}\beta^{2} \textless 4.5\times 10^{-28}, represents an improvement of about two orders of magnitude of the previous limit. The goal of VIP is to push this limit at the level of 103010^{-30}.Comment: submitted to Journal of Physics: Conference Series, by the Institute of Physic

    Produção vegetal e de óleo essencial de boldo pequeno em função de fontes de adubos orgânicos.

    Get PDF
    A aplicação de fertilizantes orgânicos, em plantas medicinais e aromáticas, normalmente modifica positivamente a produção vegetal e de óleo essencial. Neste contexto, tendo por fim avaliar a resposta de plantas de Plectranthus neochilus Schltr., cultivadas com diferentes fontes de adubos orgânicos, o presente trabalho estudou a produção de biomassa, teor, rendimento e composição química do óleo essencial. As mudas, após a aclimatização, foram transplantadas para vasos de dez litros, acondicionados em casa de vegetação. O experimento foi constituído por quatro tratamentos e quatro repetições (16 parcelas), sendo cada parcela composta por cinco vasos. Os tratamentos foram: ausência de adubo orgânico (testemunha); aplicação de 60 t ha-1 de esterco bovino; 30 t ha-1 de esterco avícola; 60 t ha-1 de composto orgânico. Aos 120 dias de cultivo, as plantas foram colhidas e uma parte das folhas frescas foi destinada à extração do óleo essencial. O restante do material vegetal foi seco em estufa, até atingir peso constante, para a determinação da biomassa seca. As análises químicas do óleo foram realizadas por cromatografia gasosa (CG-DIC e CG-EM). As fontes de adubo orgânico testadas promoveram diferenças entre os tratamentos em relação à produção de biomassa, rendimento e composição do óleo essencial de P. neochilus. A utilização de diferentes fertilizantes orgânicos não modificou o teor de óleo volátil
    corecore