1,452 research outputs found

    Semen Cryopreservation in Brazilian Freshwater Fish: Advances and Main Challenges

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    Studies on semen cryopreservation in Brazilian freshwater fish have been growing in number of publications and investigated species. Despite this apparent increase in research, standardization of cryoprotocols is still missing, making it clear that the grounds on the quality of cryopreserved semen has not yet reached a level that guarantee satisfactory results for its replication. This chapter aims to make a critical and reflective analysis on the ways cryopreservation of freshwater fish semen has been conducted in Brazil. The difficulties in standardizing protocols, broodstock, and selection of genetically superior animals; the barriers in transferring technology from laboratory benches to the field and make feasible the use of cryopreserved semen on a commercial scale; the formation of germplasm banks and the responsible use of cryopreserved material are also discussed. We have no intention to point out the successes and mistakes that may have been committed in pursuing development of cryopreservation protocols, but a reflection on the future directions considering what should be pondered on this subject with objectivity and scientific consolidation

    Perspectives for the VITO beam line at ISOLDE, CERN

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    By using polarized ion beams in combination with the β-NMR technique, the Versatile Ion-polarized Techniques On-line (VITO) experiment at ISOLDE, CERN links together expertise from different fields in an unique experimental setup. An overview of the experimental techniques and a general description of the newly designed beam line are presented. Potential uses in multidisciplinary research and perspectives for future experiments are discussed

    On the eutectoid transformation behavior of the Ti-Zn system and its metastable phases

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    To date, Zn has not been used as an alloying addition in structural Ti alloys. The main obstacle has been the disparity between their melting and vaporization temperatures. A novel processing technique was developed to create a Ti-Zn compound. The equilibrium phases and microstructures were studied by electron microscopy and x-ray diffraction techniques. Results show the presence of pearlitic domains of α-Ti (hexagonal closed packed crystal structure) and Ti2Zn (body center tetragonal structure) in regions that have a near eutectoid composition. Solutionizing and water quenching results in the formation of martensite along with intermetallic laths, suggesting that the eutectoid transformation is active

    Grupos Empresariais Na Educação Básica Pública Brasileira: Limites á Efetivação Do Direito à Educação

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    This paper analyzes, based on primary sources, mainly official and institutional documents, and on interviews with municipal managers, the performance of five business groups in municipal basic education systems. It is aimed to identify the outcomes of the adoption of private education systems by Brazilian municipalities for the composition of earmarked revenues spending for education and for the right to education. The research confirms previous studies that indicates the shift of public funds to the private sector, including transnational corporations. © 2016, Centro de Estudos Educacao e Sociedade - CEDES. All rights reserved.3713411313

    Behavioral responses of Diaphorina citri to host plant volatiles in multiple-choice olfactometers are affected in interpretable ways by effects of background colors and airflows

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    [EN] In several phytophagous hemipterans, behavior appears to be mediated by both visual and chemical cues. For the Asian citrus psyllid (ACP)Diaphorina citri(Hemiptera: Liviidae), olfactometric assays are generally difficult to interpret owing to the low proportion of individuals responding to odors (similar to 30-40%), which compromises the efficiency and reliability of the results of behavioral tests. In the present study, the ACP behavioral response to emitted odors from sweet orange (Citrus sinensisL. Osbeck) flushes in a 4-arm olfactometer using different colors (four white-, two white- and two yellow- on opposite sides, or four yellow-colored fields), and the role of the airflow in the concentration of volatile organic compounds (VOCs) were assessed at two airflows [0.4 and 0.1 L/min (LPM)]. Exposure to 'Pera' sweet orange or clean air in treatments with four yellow-colored-fields increased the response rate of ACP females to the odor sources compared with exposure to 'Pera' sweet orange or clean air in treatments with four white-colored-fields, independently of the odor source and airflow tested. For the assays using two white- and two yellow-colored fields on opposite sides and 0.4 or 0.1 LPM airflow, the residence time of ACP females to odors ('Pera' sweet orange or clean air) was similar or higher in treatments using yellow- than those using white-colored fields. For both assays (VOCs and olfactometric behavioral parameters), the reduction in airflow from 0.4 to 0.1 LPM greatly changed the airborne concentration and ACP behavior. Quantitative chemical analyses revelead that the concentration of most compounds emitted by 'Pera' sweet orange flushes for the headspace using 0.1 LPM airflow were greater than the concentrations measured using 0.4 LPM airflow. Therefore, this treatment design provides an useful tool to assess the ACP behavioral response to the odors from citrus plants, and it can also help in the discrimination of dose-response screenings for VOCs or conspecific insects.Financial support was provided by Sao Paulo Research Foundation (FAPESP) 2015/07011-3 and 2017/21460-0. The authors thank Dr. Aquidauana Miqueloto Zanardi for her help in measuring the color spaces of the white and yellow reflective papers used to change the device color.Volpe, H.; Zanardi, O.; Magnani, R.; Luvizotto, R.; Esperança, V.; De Freitas, R.; Delfino, J.... (2020). Behavioral responses of Diaphorina citri to host plant volatiles in multiple-choice olfactometers are affected in interpretable ways by effects of background colors and airflows. PLoS ONE. 15(7):1-17. https://doi.org/10.1371/journal.pone.0235630S117157Grafton-Cardwell, E. E., Stelinski, L. L., & Stansly, P. A. (2013). Biology and Management of Asian Citrus Psyllid, Vector of the Huanglongbing Pathogens. Annual Review of Entomology, 58(1), 413-432. doi:10.1146/annurev-ento-120811-153542Tiwari, S., Mann, R. S., Rogers, M. E., & Stelinski, L. L. (2011). Insecticide resistance in field populations of Asian citrus psyllid in Florida. Pest Management Science, 67(10), 1258-1268. doi:10.1002/ps.2181Zanardi, O. Z., Bordini, G. P., Franco, A. A., de Morais, M. R., & Yamamoto, P. T. (2018). Spraying pyrethroid and neonicotinoid insecticides can induce outbreaks of Panonychus citri (Trombidiformes: Tetranychidae) in citrus groves. Experimental and Applied Acarology, 76(3), 339-354. doi:10.1007/s10493-018-0316-1Stockton, D. G., Martini, X., Patt, J. M., & Stelinski, L. L. (2016). The Influence of Learning on Host Plant Preference in a Significant Phytopathogen Vector, Diaphorina citri. PLOS ONE, 11(3), e0149815. doi:10.1371/journal.pone.0149815Knolhoff, L. M., & Heckel, D. G. (2014). Behavioral Assays for Studies of Host Plant Choice and Adaptation in Herbivorous Insects. Annual Review of Entomology, 59(1), 263-278. doi:10.1146/annurev-ento-011613-161945Döring, T. F., & Chittka, L. (2007). Visual ecology of aphids—a critical review on the role of colours in host finding. Arthropod-Plant Interactions, 1(1), 3-16. doi:10.1007/s11829-006-9000-1NISSINEN, A., KRISTOFFERSEN, L., & ANDERBRANT, O. (2008). Physiological state of female and light intensity affect the host-plant selection of carrot psyllid, Trioza apicalis (Hemiptera: Triozidae). European Journal of Entomology, 105(2), 227-232. doi:10.14411/eje.2008.032MOUND, L. A. (1962). STUDIES ON THE OLFACTION AND COLOUR SENSITIVITY OF BEMISIA TABACI (GENN.) (HOMOPTERA, ALEYRODIDAE). Entomologia Experimentalis et Applicata, 5(2), 99-104. doi:10.1111/j.1570-7458.1962.tb00571.xAntignus, Y., Mor, N., Ben Joseph, R., Lapidot, M., & Cohen, S. (1996). Ultraviolet-Absorbing Plastic Sheets Protect Crops from Insect Pests and from Virus Diseases Vectored by Insects. Environmental Entomology, 25(5), 919-924. doi:10.1093/ee/25.5.919Hall, D. G., Sétamou, M., & Mizell, R. F. (2010). A comparison of sticky traps for monitoring Asian citrus psyllid (Diaphorina citri Kuwayama). Crop Protection, 29(11), 1341-1346. doi:10.1016/j.cropro.2010.06.003Godfrey, K. E., Galindo, C., Patt, J. M., & Luque-Williams, M. (2013). Evaluation of Color and Scent Attractants Used to Trap and Detect Asian Ctirus Psyllid (Hemiptera: Liviidae) in Urban Environments. Florida Entomologist, 96(4), 1406-1416. doi:10.1653/024.096.0420Sétamou, M., Sanchez, A., Saldaña, R. R., Patt, J. M., & Summy, R. (2014). Visual Responses of Adult Asian Citrus Psyllid (Hemiptera: Liviidae) to Colored Sticky Traps on Citrus Trees. Journal of Insect Behavior, 27(4), 540-553. doi:10.1007/s10905-014-9448-2Miranda, M. P., Dos Santos, F. L., Felippe, M. R., Moreno, A., & Fereres, A. (2015). Effect of UV-Blocking Plastic Films on Take-Off and Host Plant Finding Ability of Diaphorina citri (Hemiptera: Liviidae). Journal of Economic Entomology, 108(1), 245-251. doi:10.1093/jee/tou036Paris, T. M., Croxton, S. D., Stansly, P. A., & Allan, S. A. (2015). Temporal response and attraction ofDiaphorina citrito visual stimuli. Entomologia Experimentalis et Applicata, 155(2), 137-147. doi:10.1111/eea.12294Patt, J. M., & Sétamou, M. (2010). Responses of the Asian Citrus Psyllid to Volatiles Emitted by the Flushing Shoots of Its Rutaceous Host Plants. Environmental Entomology, 39(2), 618-624. doi:10.1603/en09216Amorós, M. E., Pereira das Neves, V., Rivas, F., Buenahora, J., Martini, X., Stelinski, L. L., & Rossini, C. (2018). Response of Diaphorina citri (Hemiptera: Liviidae) to volatiles characteristic of preferred citrus hosts. Arthropod-Plant Interactions, 13(3), 367-374. doi:10.1007/s11829-018-9651-8George, J., Shi, Q., Stelinski, L. L., Stover, E., & Lapointe, S. L. (2019). Host Selection, Oviposition and Feeding by a Phytopathogen Vector, Diaphorina citri (Hemiptera: Liviidae), Modulated by Plant Exposure to Formic Acid. Frontiers in Ecology and Evolution, 7. doi:10.3389/fevo.2019.00078Pettersson, J. (1970). An Aphid Sex Attractant. Insect Systematics & Evolution, 1(1), 63-73. doi:10.1163/187631270x00357VET, L. E. M., LENTEREN, J. C. V., HEYMANS, M., & MEELIS, E. (1983). An airflow olfactometer for measuring olfactory responses of hymenopterous parasitoids and other small insects. Physiological Entomology, 8(1), 97-106. doi:10.1111/j.1365-3032.1983.tb00338.xWenninger, E. J., Stelinski, L. L., & Hall, D. G. (2009). Roles of Olfactory Cues, Visual Cues, and Mating Status in Orientation of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) to Four Different Host Plants. Environmental Entomology, 38(1), 225-234. doi:10.1603/022.038.0128Onagbola, E. O., Rouseff, R. L., Smoot, J. M., & Stelinski, L. L. (2010). Guava leaf volatiles and dimethyl disulphide inhibit response of Diaphorina citri Kuwayama to host plant volatiles. Journal of Applied Entomology, 135(6), 404-414. doi:10.1111/j.1439-0418.2010.01565.xAlquézar, B., Volpe, H. X. L., Magnani, R. F., de Miranda, M. P., Santos, M. A., Wulff, N. A., … Peña, L. (2017). β-caryophyllene emitted from a transgenic Arabidopsis or chemical dispenser repels Diaphorina citri, vector of Candidatus Liberibacters. Scientific Reports, 7(1). doi:10.1038/s41598-017-06119-wTomaseto, A. F., Miranda, M. P., Moral, R. A., de Lara, I. A. R., Fereres, A., & Lopes, J. R. S. (2017). Environmental conditions for Diaphorina citri Kuwayama (Hemiptera: Liviidae) take-off. Journal of Applied Entomology, 142(1-2), 104-113. doi:10.1111/jen.12418Wenninger, E. J., & Hall, D. G. (2007). Daily Timing of Mating and Age at Reproductive Maturity in Diaphorina citri (Hemiptera: Psyllidae). Florida Entomologist, 90(4), 715-722. doi:10.1653/0015-4040(2007)90[715:dtomaa]2.0.co;2Shapiro, S. S., & Wilk, M. B. (1965). An Analysis of Variance Test for Normality (Complete Samples). Biometrika, 52(3/4), 591. doi:10.2307/2333709Nelder, J. A., & Wedderburn, R. W. M. (1972). Generalized Linear Models. Journal of the Royal Statistical Society. Series A (General), 135(3), 370. doi:10.2307/2344614Wilcoxon, F. (1945). Individual Comparisons by Ranking Methods. Biometrics Bulletin, 1(6), 80. doi:10.2307/3001968Patt, J. M., Meikle, W. G., Mafra-Neto, A., Sétamou, M., Mangan, R., Yang, C., … Adamczyk, J. J. (2011). Multimodal Cues Drive Host-Plant Assessment in Asian Citrus Psyllid (Diaphorina citri). Environmental Entomology, 40(6), 1494-1502. doi:10.1603/en11149Todd, J. W., Kays, S. J., & Kays, S. E. (1977). A precision low-flow-rate air delivery system for use with olfactometers. Journal of Chemical Ecology, 3(5), 519-525. doi:10.1007/bf00989073Bruce, T. J. A., Wadhams, L. J., & Woodcock, C. M. (2005). Insect host location: a volatile situation. Trends in Plant Science, 10(6), 269-274. doi:10.1016/j.tplants.2005.04.003Bruce, T. J. A., & Pickett, J. A. (2011). Perception of plant volatile blends by herbivorous insects – Finding the right mix. Phytochemistry, 72(13), 1605-1611. doi:10.1016/j.phytochem.2011.04.01

    Universality of the thermodynamic Casimir effect

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    Recently a nonuniversal character of the leading spatial behavior of the thermodynamic Casimir force has been reported [X. S. Chen and V. Dohm, Phys. Rev. E {\bf 66}, 016102 (2002)]. We reconsider the arguments leading to this observation and show that there is no such leading nonuniversal term in systems with short-ranged interactions if one treats properly the effects generated by a sharp momentum cutoff in the Fourier transform of the interaction potential. We also conclude that lattice and continuum models then produce results in mutual agreement independent of the cutoff scheme, contrary to the aforementioned report. All results are consistent with the {\em universal} character of the Casimir force in systems with short-ranged interactions. The effects due to dispersion forces are discussed for systems with periodic or realistic boundary conditions. In contrast to systems with short-ranged interactions, for L/ξ≫1L/\xi \gg 1 one observes leading finite-size contributions governed by power laws in LL due to the subleading long-ranged character of the interaction, where LL is the finite system size and ξ\xi is the correlation length.Comment: 11 pages, revtex, to appear in Phys. Rev. E 68 (2003

    Interação da temperatura com o ácaro parasita Acarophenax lacunatus (Cross & Krantz) (Prostigmata: Acarophenacidae) sobre o desenvolvimento de Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae)

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    O presente trabalho teve como objetivo avaliar o efeito da interação de diferentes temperaturas com o parasita Acarophenax lacunatus (Cross & Krantz) na supressão populacional de Rhyzopertha dominica (Fabricius). Os ensaios foram realizados com e sem o parasita, em cinco repetições, às temperaturas de 20, 25, 30 e 35ºC, umidade relativa de 60 ± 5% e escotofase de 24h. As unidades experimentais consistiram de placas de Petri, contendo 40 g de grãos de trigo (13% b.u.), infestados com 10 adultos de R. dominica. Foram realizadas três inoculações de cinco fêmeas de A. lacunatus por placa de Petri. As avaliações foram realizadas depois de 20, 40, 60, 80, 100 e 120 dias do início do experimento. A interação da temperatura com A. lacunatus mostrou ser uma importante ferramenta para a supressão populacional de R. dominica. Todavia, em temperaturas maiores que 25ºC, mesmo A. lacunatus reduzindo grande proporção das fases imaturas de R. dominica, as perdas de massa dos grãos foram elevadas aos 120 dias do armazenamento. A manutenção da temperatura dos grãos armazenados a 20ºC pode ser usada como complemento para o controle biológico de R. dominica com A. lacunatus.The objective of this study was to evaluate the effect of different temperatures with the association of the mite Acarophenax lacunatus (Cross & Krantz) on the population suppression of Rhyzopertha dominica (Fabricius). The experimental units were petri dishes containing 40 g of whole wheat grains (13% moisture content) infested with 10 adults of R. dominica, under the temperatures of 20, 25, 30 and 35ºC, with or without A. lacunatus, in five replicates. Relative humidity of 60 ± 5% and escotophase of 24h were used for all temperatures. Five days after the infestation, five mites were inoculated in each experimental unit. The evaluations were carried out at 20, 40, 60, 80, 100 and 120 days after R. dominica infestation. The interaction of the temperature with the parasite A. lacunatus was an important tool for the population suppression of R. dominica. In temperatures higher than 25ºC, however, despite the reduction of the immature stages of R. dominica, there was a high grain weight loss after 120 days. The maintenance of the temperature of the wheat grains stored at 20ºC can be used to complement the biological control of R. dominica with A. lacunatus

    Prevalence and predictors of coronary artery disease in patients with a calcium score of zero

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    The absence of coronary calcification is associated with an excellent prognosis. However, a calcium score of zero does not exclude the presence of coronary artery disease (CAD) or the possibility of future cardiovascular events. Our aim was to study the prevalence and predictors of coronary artery disease in patients with a calcium score of zero. Prospective registry consisted of 3,012 consecutive patients that underwent cardiac CT (dual source CT). Stable patients referred for evaluation of possible CAD that had a calcium score of zero (n = 864) were selected for this analysis. The variables that were statistically significant were included in a multivariable logistic regression model. From 864 patients with a calcium score of zero, 107 (12.4 %) had coronary plaques on the contrast CT (10.8 %, n = 93 with nonobstructive CAD and 1.6 %, n = 14 with obstructive CAD). By logistic regression analysis, the independent predictors of CAD in this population were age >55 years [odds ratio (OR) 1.63 (1.05-2.52)], hypertension [OR 1.64 (1.05-2.56)] and dyslipidemia [OR 1.54 (1.00-2.36)]. In the presence of these 3 variables, the probability of having coronary plaques was 21 %. The absence of coronary artery calcification does not exclude the presence of coron

    Non-standard Hamiltonian effects on neutrino oscillations

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    We investigate non-standard Hamiltonian effects on neutrino oscillations, which are effective additional contributions to the vacuum or matter Hamiltonian. Since these effects can enter in either flavor or mass basis, we develop an understanding of the difference between these bases representing the underlying theoretical model. In particular, the simplest of these effects are classified as ``pure'' flavor or mass effects, where the appearance of such a ``pure'' effect can be quite plausible as a leading non-standard contribution from theoretical models. Compared to earlier studies investigating particular effects, we aim for a top-down classification of a possible ``new physics'' signature at future long-baseline neutrino oscillation precision experiments. We develop a general framework for such effects with two neutrino flavors and discuss the extension to three neutrino flavors, as well as we demonstrate the challenges for a neutrino factory to distinguish the theoretical origin of these effects with a numerical example. We find how the precision measurement of neutrino oscillation parameters can be altered by non-standard effects alone (not including non-standard interactions in the creation and detection processes) and that the non-standard effects on Hamiltonian level can be distinguished from other non-standard effects (such as neutrino decoherence and decay) if we consider specific imprint of the effects on the energy spectra of several different oscillation channels at a neutrino factory.Comment: 30 pages, 6 figures, LaTeX, final version, published in Eur.Phys.J.
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