On The Interplay Between Symmetry Breaking, Integrability, And Chaos In The Semiclassical Limit Of The Heisenberg System

In this work we present a detailed numerical analysis of the interplay between symmetry breaking, integrability, and chaos in the two- and three-spin Heisenberg models. The results suggest that a very simple and powerful tool to convey such information are the plots of the energy level spacings Δn, versus the energy level index n, together with the correlation plots Δn+1x Δn. When integrability is broken, these plots are shown to identify very sharply an energy below which one has chaotic behavior. The particularly strong point in favor of such analysis is that it can be useful in partially chaotic regimes. © 1995 American Institute of Physics. © 1995 American Institute of Physics.5246347

Quantum Entanglement and fixed point Hopf bifurcation

We present the qualitative differences in the phase transitions of the mono-mode Dicke model in its integrable and chaotic versions. We show that a first order phase transition occurs in the integrable case whereas a second order in the chaotic one. This difference is also reflected in the classical limit: for the integrable case the stable fixed point in phase space suffers a bifurcation of Hopf type whereas for the second one a pitchfork type bifurcation has been reported

Simulations Of Microclimate In Greenhouses Aiming The Acclimatization Of Micropropagated Seedlings Of Banana Cv. Grande Naine [estudo De Simulações De Microclimas Em Casas De Vege Tação Visando ã Aclimatação De Mudas Micropropagadas De Bananeira Cv Grande Naine]

In acclimatization processes, the environment control takes over a part of vital importance, since in in vitro condition banana seedlings do not efficiently operate the absorption of light, water and nutrients. Therefore, they should be submitted to controlled environments under feasible conditions of luminosity, temperature (around 28°C, with minimum of 18°C and maximum of 34°C), and relative humidity above 75%. For this purpose, it was installed five mini tunnels with controlled temperature and relative humidity. For the control of temperature it was used pad-fan evaporative coolers at 28/25°C. For the control of relative humidity it was used fogging during the day at 75% under intermittence of 6s at each 40s. For temperature and relative humidity monitoring, it was installed three aspirate psychrometers in each mini tunnel connected to a data logger for daily acquisition every 60s. Temperature and relative air humidity were adequate for plants development, however significant differences were observed between the different environment conditions. For luminosity study, under transparent plastic film (low density polyethylene) of 100μm thickness, it was used four meshes with average shading in the PAR spectrum band (400 to 700nm) of 69.92%, 50.73%, 29.73%, and 57.77%, being the first three in red color (with top level at 580nm, and abrupt reduction after that), the fourth mesh was black (linear behavior). The fifth tunnel had only transparent plastic film, showing 12.74% of solar radiation interception. These values were obtained from paired samples (mesh and plastic film) for the first four tunnels, and only the transparent plastic film for the last, using a spectral radiometer (400 to 1100nm), with spectral resolution of 2nm. Inside and outside of each environment it was obtained global and PAR irradiance by using calibrated photovoltaic sensors at 9:00,12:00, and 3:00, under clean and cloudy sky, during the summer of 2004/05, and winter of 2005. The red mesh presented differentiated transmittances at the PAR spectrum band which established an interesting material for acclimatization studies. Results show bigger reductions on the PAR spectrum band for the red mesh, regardless of time, solar radiation, or seasons, which agree with the results obtained by the spectral radiometer.30410011008ABREU, deABREU, V.M.N.MAZZUCO, H. Uso do resfriamento evaporativo (adiabático) na criação de frangos de corte, Concórdia: EMBRAPA, CNPSA, 1999.5 lp. (Documentos, 59)BUCKL1N, R.A.LEARY, J.D.MCCONNELL, D.B.W1LKERSON, E.G. Fan and pad greenhouse evaporative cooling systems. Gainsville: Department of Agricultural and Biological Engineering, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. 2003 (Circular, 1135). Disponível em: 〈http://edis.ifas.ufl.edu/ AE069〉. Acesso em: 16 abr.2004CHURCH, G.A., WATERS, W.F., LAZIN, M.B., (1981) Application of ground water to greenhouse cooling systems, pp. 15-18. , Chicago: American Society of Agricultural EngineersFARIA JUNIOR, M. J. A.LIMA, A. M. Uso de Sombreamento em Estufa Coberta com Polietileno e com ventilação natural: efeitos sobre variáveis climáticas. In: CONGRESSO BRASILEIRO DEENGENHARIAAGRÍCOLA, 29., 2000, Fortaleza. Anais... 2000FARIAS, J.R.B., BERGAMASCHI, H., MARTINS, S.R., BERLATO, M.A., OLIVEIRA, A.C.B., Alterações na temperatura e umidade do ar provocadas pelo uso de estufa plástica. (1993) Revista Brasileira de Agrometeorologia, 1 (1), pp. 51-62. , Campinas, vFRISINA, V.A.ESCOBEDO, J.F.GOMES, E.N. Estimativa da radiação fotossinteticamente ativa (PAR) em estufa de polietileno. In: ENCONTRO DE ENERGIA NO MEIO RURAL, 3., 2000, Campinas. Disponível em: 〈http://www.proceedings.scielo.br/ scielo.php?script=sci-arttex&pid= MSC000000002200000 0200056&lng=en&nrm=abn〉. Acesso em: 18 maio 2006HOFFMANN, A., Aclimataçáo de mudas produzidas in vitro e in vivo (2002) Informe Agropecuario, 23 (216), pp. 21-24. , Belo Horizonte, vLARCHER, W., (2000) Ecofisiologia vegetal, , São Carlos: Rima, 531pLEAL, P.A.M., (2003) Radiação solar: Curso estudo dirigido em construções rurais e ambiência, pp. 36 f. , Campinas: Faculdade de Engenharia Agrícola, Notas de aulaMARIE, P., L'acclimatation des vitroplants de bananiers de Grandee Naine (1995) Montepellier: CIRAD-FLHOR, , 21 pMARTIN, E.C., ROBLEDO, L.V., (1981) Aplicación de los plásticos en la agricultura, , Madrid: Mund-Pressa, 55pMARTINS, S.R., GONZALEZ, J.F., Avaliação do resfriamento em estufa plástica mediante sistema de ventilaçao e nebulizagão. (1995) Revista Brasileira de Agrometeorologia, 3, pp. 13-18. , Campinas, vMELO, E.C., LOPES, D.C., CORRÊA, P.C., GRAPSI - Programa computacional para o cálculo das propriedades psicrométricas do ar (2004) Engenharia na Agricultura, 12 (2), pp. 154-162. , http://www.ufv.br/dea/reveng/arquivos/voll2/vl2n2pl54-162.pdf, Viçosa, v, Disponível em:, Acesso em: 29nov. 2005MENDES, N., (1997) Programa computacional para cálculo de umidade relativa ou temperatura de bulbo úmido, , http://www.labeee.ufsc.br/software/psychros.html, Florianópolis: Laboratório de Eficiência Energética em Edificaç ões. Universidade Federal de Santa Catarina, Disponível em:, Acesso em: 04jul.2006MONTERO, J.I., CASTILLA, N., GUTIERREZ de, R.E., BRETONES, F., Climate under plastic in the Almeria (1985) Acta Horticulturae, (170), pp. 227-234. , WageningenMONTERO, J.I.ANTÓN, A.BIEL, CFRANQUET, A. Cooling of greenhouse with compressed air fogging nozzles. Acta Horticulturae, Wageningen, n.281,p.l99-209,1990MONTERO, J.I., ANTON, A., Greenhouse cooling during warm periods (1994) Acta Horticulturae, 357, pp. 49-61. , Wageningen, vSEEMAN, J., Greenhouse climate (1979) Agrometeorology, pp. 165-178. , Seeman, J, Chirkov, Y.I, Lomas, J, Primault, B, Berlin: Springer-Verlag BerlinSHAHAK, Y.GUSSAKOVSKY, E. E.COHEN, YLURIE, S.STERN, R.KFIR, S.NAOR, A.ATZMON, I.DORON, I. e GREENBLAT-AVRON, Y. ColorNets: A New Approach for Light Manipulation in Fruit Trees. Acta Horticulturae, Wageningen, v.636,p.609-616,2004SILVA, D.S., BOSISIO, A., BOSCAROL, B., BELTZER, A., AMSLER, G.P., Aclimatação de mudas de bananeira (Musa spp.) "Prata" (AAB) em diferentes substratos (1999) Revista Ceres, 46 (267), pp. 543-554. , Viçosa, vSOUZA, A. S.DANTAS, J.L.L.SOUZA, F. V. D.CORDEIRO, Z. J. M.SILVANETO, S. P. Propagação. In: ALVES, E. J. (Org.). A cultura da banana: aspectos técnicos, socioeconômics e agroindustriais. Brasília: EMBRAPA-SPI, 1997. p. 151-195TAIZ, L., ZEIGER, E., (2004) Fisiologia vegetal, , Porto Alegre: Artmed, 719pTOYOMATSU, T., KAWAIDE, H., INOUE, Y., KAMIYA, Y., Phytochrome regulates gibberellin biosynthesis during germination of photoblastic lecttuce seeds (1998) Plant Physiology, 118, pp. l517-l523. , Stuttgart, vWHITAKER, J.H. Agricultural building and structure. Heston: Heston Publishing Company, 1979.289

Spectral variables, growth analysis and yield of sugarcane Variáveis espectrais e indicadores de desenvolvimento e produtividade da cana-de-açúcar

Spectral information is well related with agronomic variables and can be used in crop monitoring and yield forecasting. This paper describes a multitemporal research with the sugarcane variety SP80-1842, studying its spectral behavior using field spectroscopy and its relationship with agronomic parameters such as leaf area index (LAI), number of stalks per meter (NPM), yield (TSS) and total biomass (BMT). A commercial sugarcane field in Araras/SP/Brazil was monitored for two seasons. Radiometric data and agronomic characterization were gathered in 9 field campaigns. Spectral vegetation indices had similar patterns in both seasons and adjusted to agronomic parameters. Band 4 (B4), Simple Ratio (SR), Normalized Difference Vegetation Index (NDVI), and Soil Adjusted Vegetation Index (SAVI) increased their values until the end of the vegetative stage, around 240 days after harvest (DAC). After that stage, B4 reflectance and NDVI values began to stabilize and decrease because the crop reached ripening and senescence stages. Band 3 (B3) and RVI presented decreased values since the beginning of the cycle, followed by a stabilization stage. Later these values had a slight increase caused by the lower amount of green vegetation. Spectral variables B3, RVI, NDVI, and SAVI were highly correlated (above 0.79) with LAI, TSS, and BMT, and about 0.50 with NPM. The best regression models were verified for RVI, LAI, and NPM, which explained 0.97 of TSS variation and 0.99 of BMT variation.<br>A informação espectral tem boa relação com variáveis agronômicas e pode contribuir com informações para o monitoramento, acompanhamento e previsão de safras. O presente trabalho descreve a análise multitemporal do comportamento espectral da variedade de cana-de-açúcar SP80-1842 e a relação com variáveis agronômicas como índice de área foliar (IAF), número de perfilhos por metro (NPM), produtividade (TCH) e biomassa total (BMT). Nas safras 2000/2001 e 2001/2002, um talhão comercial, localizada no município de Araras/SP foi monitorado em nove campanhas de coleta de dados radiométricos e agronômicos. O comportamento temporal das variáveis espectrais acompanhou o comportamento das variáveis agronômicas. A banda 4 (B4), o índice de vegetação da razão simples (SR), o índice de vegetação por diferença normalizada (NDVI) e o índice de vegetação ajustado ao solo (SAVI) aumentaram seus valores até o fim da fase de crescimento vegetativo, aproximadamente até os 240 dias após o corte, a partir do qual os valores se estabilizaram e diminuíram em função da entrada da cultura na fase de maturação. A banda 3 (B3) e o índice de vegetação da razão (RVI) tiveram queda em seus valores desde o início do ciclo, com posterior estabilização e aumento em seus valores devido ao aumento da quantidade de palha e da queda da biomassa foliar. As variáveis espectrais B3, RVI, NDVI e SAVI tiveram correlações maiores que 0,79 com as variáveis IAF e BMT e de aproximadamente 0,50 com o NPM. Os melhores modelos de regressão linear múltipla foram os com RVI, IAF e NPM e explicaram 0,97 da variação da TCH e 0,99 da BMT