1,421 research outputs found

    Photo Acoustic Study Of Plants Exposed To Varying Light Intensity Growth Conditions: Spectral And Morphological Changes

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    In this paper we describe results of photo acoustic (PA) measurements carried out on various plants exposed to varying light intensity conditions. Depending on the species and light intensity conditions, the PA absorption spectra show differences in peaks associated with pigments and the cuticle. These differences are related to the spatial distribution of the pigments that differs from plant to plant. We have also performed systematic study of oxygen evolution at different wavelengths. The obtained oxygen spectra are equivalent to the action spectra usually acquired by determining the CO2 uptake and energy storage. The intensities of oxygen spectra exhibit differences depending on distinct morphology of plant. © EDP Sciences.125745748Marquezini, M.V., Cella, N., Mansanares, A.M., Vargas, H., Miranda, L.C.M., (1991) Meas. Sci. Technol., 2, p. 396Barja, P.R., Mansanares, A.M., (1998) Instrum. Sci. Technol., 26, p. 209Barja, P.R., Mansanares, A.M., Da Silva, E.C., Magalhães, A.C.N., Alves, P.L.C.A., (2001) Photosynthetica, 39, p. 489Salisbury, F.B., Ross, C.W., (1992) Plant Physiology, , Wadsworth Publishing Company, CaliforniaClark, J.B., Lister, G.R., (1975) Plant Physiol., 55, p. 401Carpentier, R., Larue, B., Leblanc, R.M., (1983) J. Physique Colloque C6, 44 (10 SUPL), pp. 355-360Veeranjaneyulu, K., Charland, M., Charlebois, D., Leblanc, R.M., (1991) Photosynth. Res., 30, p. 13

    Optimized Profile Retrievals of Aerosol Microphysical Properties from Simulated Spaceborne Multiwavelength Lidar

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    This work is an expanded study of one previously published on retrievals of aerosol microphysical properties from space-borne multiwavelength lidar measurements. The earlier studies and this one were done in the framework of the NASA Aerosol-Clouds-Ecosystems (now the Aerosol Clouds Convection and Precipitation) NASA mission. The focus here is on the capabilities of a simulated spaceborne multiwavelength lidar system for retrieving aerosol complex refractive index (m = mr + imi) and spectral single scattering albedo (SSA(λ)), although other bulk parameters such as effective (reff) radius and particle volume (V) and surface (S) concentrations are also studied. The novelty presented here is the use of recently published, case-dependent optimized-constraints on the microphysical retrievals using three backscattering coefficients (β) at 355, 532 and 1064 nm and two extinction coefficients (α) at 355 and 532 nm, typically known as the stand-alone 3β + 2α lidar inversion. Case-dependent optimized-constraints (CDOC) limit the ranges of refractive index, both real (mr) and imaginary (mi) parts, and of radii that are permitted in the retrievals. Such constraints are selected directly from the 3β + 2α measurements through an analysis of the relationship between spectral dependence of aerosol extinction-to-backscatter ratios (LR) and the Ångström exponent of extinction. The analyses presented here for different sets of size distributions and refractive indices reveal that the direct determination of CDOC are only feasible for cases where the uncertainties in the input optical data are less than 15%. For the same simulated spaceborne system and yield than in Whiteman et al., (2018), we demonstrated that the use of CDOC as essential for the retrievals of refractive index and also largely improved retrieval of bulk parameters. A discussion of the global representativeness of CDOC is presented using simulated lidar data from a 24 h satellite track using GEOS model output to initialize the lidar simulator. We found that CDOC are representative of many aerosol mixtures in spite of some outliers (e.g. highly hydrated particles) associated with the assumptions of bimodal size distributions and of the same refractive index for fine and coarse modes. Moreover, sensitivity tests performed using synthetic data reveal that retrievals of imaginary refractive index (mi) and SSA are extremely sensitive to β(355).Marie Skłodowska-Curie Research Innovation and Staff Exchange(RISE) GRASP-ACE (grant agreement No 778349

    Characterization Of Human Skin Through Photoacoustic Spectroscopy

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    The photoacoustic technique is based on the absorption of modulated light by a sample and subsequent heat generation. This generates thermal waves that propagate in the surrounding media According to the Rosencwaig-Gersho Model, such waves produce the pressure oscillation detected as the photoacoustic signal. This technique allows the spectroscopic characterization of multilayer systems: as the thermal diffusion length varies with the modulation frequency of the absorbed light, the depth profile of a sample can be studied by the analysis of the photoacoustic signal at different modulation frequencies. In this work, photoacoustic spectroscopy was used to characterize different human skin samples. Measurements were performed at 70Hz and 17Hz, using a 1000W Xe arc lamp as the light source, for wavelengths between 240nm and 700nm. Skin samples were about 0,5cm diameter. It was possible to obtain the photoacoustic absorption spectra of the stratum corneum and of a deeper layer of epidermis; when the lower modulation frequency is utilized, photoacoustic spectroscopy characterizes the absorption of the whole epidermis, because in this case the thermal diffusion length is thicker than that of the stratum corneum. Photoacoustic spectroscopy was also employed to monitor the drying kinetics of the skin. This was done by analyzing the time evolution of the photoacoustic spectra of skin samples. Pre-treatment of the samples included different periods in a drying chamber. Measurements show that the photoacoustic spectra changes according to the humidity of the skin. Future work includes detailed monitoring of skin hydration.5325136142Morganti, P., Ruocco, E., Wolf, R., Ruocco, V., Percutaneous absorption and delivery systems (2001) Clinics in Dermatology, 19, pp. 489-501Junqueira, L.C., Carneiro, J., (1995) Histologia Básica, 8a Ed., pp. 301-303Bernengo, J.C., Gasquez, C., Falson-Rieg, F., Photoacoustics as a tool for cutaneous permeation studies (1998) High Temperatures-High Pressures, 30, pp. 619-624Gutiérrez-Juárez, G., Vargas-Luna, M., Córdova, T., Varela, J.B., Bernal-Alvarado, J.J., Sosa, M., In vivo measurement of the human skin absorption of toppically applied substances by photoacoustic technique (2002) Physiological Measurement, 23, pp. 1-12Puccetti, G., Lahjomri, F., Leblanc, R.M., Pulsed photoacoustic spectroscopy applied to the diffusion of sunscreen chromophores in human skin: The weakly absorbent regime (1997) Journal of Photochemistry and Photobiology B: Biology, 39, pp. 110-120Vinha, C.A., Haas, U., Qualitative and semiquantitative analysis of dried fruits and seasoning products of paprika using photoacoustic spectroscopy (1997) Journal of Agricultural and Food Chemistry, 45 (4), p. 127

    Photoacoustics As A Tool For The Diagnosis Of Radicular Stress: Measurements In Eucalyptus Seedlings

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    The application of the open photoacoustic cell (OPC) to investigate the behavior of eucalyptus leaves by the availability of soil and nutrients for the seedlings was discussed. Fluorescence and photosynthetic rate were evaluated in vivo and in situ, the latter one using the open photoacoustic technique. It was shown that the photosynthetic behavior of seedings are affected by radicular stress, with the soil volume of the pot becoming insufficient for the roots, causing a nutritional deficiency in plants.741 II709711Fork, D.C., Herbert, S.K., (1993) Photochem. Photobiol., 57, p. 207Malkin, S., Canaani, O., (1994) Annu. Rev. Plant Physiol. Plant Mol. Biol., 45, p. 493Malkin, S., Puchenkov, O., (1997) Progress in Photothermal and Photoacoustic Science, Life and Earth Sciences, 3, pp. 17-56. , edited by A. Mandelis and P. Hess (SPIE, Bellingham, WA)Herbert, S.K., Han, T., Vogelmann, T.C., (2000) Photosynth. Res., 66, p. 13Malkin, S., (1987) Planta, 171, p. 65Perondi, L.F., Miranda, L.C.M., (1987) J. Appl. Phys., 62, p. 2955Marquezini, M.V., Cella, N., Mansanares, A.M., Vargas, H., Miranda, L.C.M., (1991) Meas. Sci. Technol., 2, p. 396Pereira, A.C., Neto, G.D.O., Vargas, H., Cella, N., Miranda, L.C.M., (1994) Rev. Sci. Instrum., 65, p. 1512Silva, W.J., Prioli, L.M., Miranda, L.C.M., Cella, N., Vargas, H., Mansanares, A.M., (1995) Plant Sci., 104, p. 177Barja, P.R., Mansanares, A.M., (1998) Instrum. Sci. Technol., 26, p. 209Blake, S.T., (1977) Austrobaileya, 1, p. 7Pryor, L.D., Williams, E.R., Gunn, B.V., (1995) Aust. Syst. Bot., 8, p. 7Inoue, M.T., Oda, S., (1998) Proceedings of the International Symposium on Forest Tree Physiology, p. 69. , NancyBarja, P.R., Mansanares, A.M., Da Silva, E.C., (2001) Acoust. Phys., 47, p. 1

    Sunscreen Effects In Skin Analyzed By Photoacoustic Spectroscopy

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    In the photoacoustic technique, the signal is proportional to the heat produced in a sample as a consequence of modulated light absorption. This technique allows the spectroscopic characterization of multilayer systems: as the thermal diffusion length varies with the light modulation frequency, one can obtain the depth profile of the sample by analyzing the frequency-dependence of the signal. As the photoacoustic signal depends on thermal and optical properties of the sample, structural changes in the system under analysis account for signal variations in time. In this work, photoacoustic spectroscopy was used to characterize samples of sunscreen and the system formed by sunscreen plus skin. Measurements used a 1000W Xe arc lamp as light source, for wavelengths between 240nm and 400nm. This range corresponds to most of the UV radiation that reaches Earth. Skin samples were disks of about 0,5cm diameter. The absorption spectrum of sunscreen was obtained. Finally, photoacoustics was employed to monitor the absorption kinetics of the sunscreen applied to skin samples. This was done by applying sunscreen in a skin sample and recording the photoacoustic spectra in regular time intervals, up to 90 minutes after application. According to measurements, light absorption by the sunscreen plus skin system stabilizes between 25 and 45 minutes after sunscreen application. Results show that this technique can be utilized to monitor drug delivery and farmacokinetics in skin samples.5325143149Barja, P.R., (1996) Estudo da Indução Fotossintética Através da Técnica Fotoacústica: Efeitos de Saturação e Fotoinibição, , (master thesis), IFGW, UNICAMPRosencwaig, A., (1980) Photoacoustics and Photoacoustic Spectroscopy, pp. 219-231. , New York, John Wiley & SonsPucceti, G., Leblanc, R.M., A comparative study on chromophore diffusion inside porous filters by pulsed photoacoustic spectroscopy (1996) Journal of Membrane Science, 119, pp. 213-228Gutiérrez-Juárez, G., Vargas-Luna, M., Córdova, T., In vivo measurement of the human skin absorption of topically applied substances by photoacoustic technique (2002) Physiological Measurement, 23, pp. 1-12Bernengo, J.C., Photoacoustics as a tool for cutaneous permeation studies (1998) High Temperatures-high Pressures, 30, pp. 619-624Azevedo, J.S., UVA/UVB sunscreen determination by second-order derivative ultraviolet spectrophotometry (1999) II Farmaco, 54, pp. 573-578Rettberg, P., Horneck, G., Biologically weighted measurement of UV radiation in space on Earth with the biofilm technique (2000) Advanced Space Research, 26, pp. 2005-2014Van Der Leun, J.C., UV radiation from sunlight: Summary, conclusions and recommendations (1996) Journal of Photochemistry and Photobiology B: Biology, 35, pp. 237-2441Wolf, R., Sunscreens (2001) Clinics in Dermatology, 19, pp. 452-45

    Water requirements and single and dual crop coefficients of sugarcane grown in a tropical region, Brazil

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    A field experiment was conducted throughout 2009/2010 in a sugarcane field of a commercial distillery located on the coastal area of Paraiba state, Brazil. The objectives were to determine sugarcane water requirements and to test the single and dual crop coefficients by comparing the calculated values of ET with measured ones. Crop evapotranspiration was determined by field water balance, reference evapotranspiration (ETo) by the Penman-Monteith approach, while single and dual crop coefficients were computed through the standard FAO-56 methodology. The experi- mental area was cultivated with irrigation ap-plied weekly by a centre pivot system in addition to rainfall and the irrigation scheduling was based on 100% ETo. Three statistical tests, mean bias difference (MBD), normalized root mean square difference (NRMSD) and regression analysis, were used to evaluate the performance of single and dual crop coefficients. Results showed that there was a notable symmetry between ET meas- ured and ET calculated by Kc dual. The ET val- ues, calculated from Kc single, underestimated those obtained from soil water balance meas- urements by 36%

    Quality of cut and basecutter blade configuration for the mechanized harvest of green sugarcane

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    Quality control is used to evaluate processes and products, and is a powerful tool for reducing variability. The objective of this study was to evaluate the quality of green sugarcane (Saccharum spp.) cutting for mechanized harvest, using statistical quality control tools. Cutting height and damage to ratoon stalks caused by different blade and disc combinations of the basecutter mechanism were used as indicators of quality. Cutting height showed high variability with a controlled process for some treatments. However, these treatments were incapable of producing satisfactory results. The damage index was lower in treatments that used tilted blades, but above the target for all treatments, which caused significant damage to the ratoons. In general, the process of mechanized harvest as assessed by these indicators was found incapable of achieving targeted results and staying below specification limits, and thus requires corrective actions to improve quality

    Description Of The Hemipenial Morphology Of Tupinambis Quadrilineatus Manzani And Abe, 1997 (squamata, Teiidae) And New Records From Piauí, Brazil

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    Few data are available on the morphology of the hemipenis of teiid lizards, especially those of the recentlydefined genus Tupinambis, a widely-distributed group of large-bodied lizards. This study provides an illustrated description of the hemipenis of Tupinambis quadrilineatus, which is similar to that of other representatives of the Tupinambinae subfamily. New records of the species from the state of Piauí, in northeastern Brazil, are also presented. © Marcélia Basto da Silva et al.3616172Avila-Pires, T.C.S., (1995) Lizards of Brazilian Amazonia (Reptilia: Squamata), p. 706. , Zoologische VerhandelingenBarreto, L., Arzabe, C., Lima, Y.C.C., Herpetofauna da região de Balsas (2007) Cerrado Norte do Brasil, pp. 221-229. , In: Barreto L (Ed), USEB, PelotasBöhme, W., Zur Genitalmorphologie der Sauria: Funktionelle und stammesgeschichtliche Aspekte (1988) Bonner Zoologische Monographien, 27, pp. 1-176Colli, G.R., Péres Jr., A.K., Cunha, H.J., A new species of Tupinambis (Squamata: Teiidae) from Central Brazil, with an analysis of morphological and genetic variation in the genus (1998) Herpetologica, 54 (4), pp. 477-492Cope, E.D., On the hemipenes of the Sauria (1896) Proceedings of the Academy of Natural Sciences of Philadelphia, 48, pp. 461-467Costa, H.C., São Pedro, V.A., Péres, A.K., Feio, N.R., Reptilia, Squamata, Teiidae, Tupinambis longilineus: Distribution extension (2008) Check List, 4, pp. 267-268Dal Vechio, F., Recoder, R., Rodrigues, M.T., Zaher, H., The herpetofauna of the Estação Ecológica de Uruçuí-Una, state of Piauí, Brazil (2013) Papéis Avulsos de Zoologia, 53 (16), pp. 225-243. , doi: 10.1590/S0031-10492013001600001Dowling, H.G., Duellman, W.E., (1978) Systematic Herpetology: A Synopsis of Families and Higher Categories, p. 118. , HISS Publications, New YorkFerreira, L.V., Pereira, J.L.G., Avila-Pires, T.C.S., Chaves, P.P., Cunha, D.A., Furtado, C.S., Primeira ocorrência de Tupinambis quadrilineatus Manzani, Abe, 1997 (Squamata: Teiidae) no bioma Amazônia (2009) Boletim do Museu Paraense Emílio Goeldi Ciências Naturais, 4 (3), pp. 355-361Fitzgerald, L.A., Cook, J.A., Aquino, A.J., Molecular phylogenetics and conservation of Tupinambis (Sauria: Teiidae) (1999) Copeia, pp. 894-905. , doi: 10.2307/1447965Guimarães, T.C.S., Figueiredo, G.B., Salmito, W.E., Geographic distribution: Tupinambis quadrilineatus (2007) Herpetological Review, 38 (3), pp. 353-354Harvey, M.B., Ugueto, G.N., Gutberlet, R.L., Review of Teiid Morphology with a Revised Taxonomy and Phylogeny of the Teiidae (Lepidosauria: Squamata) (2012) Zootaxa, pp. 1-156. , http://zoobank.org/References/457C2AD0-E5CF-4A41-B6CB-11722700BC5FLangstroth, R.P., Adiciones probables y confirmadas para la saurofauna boliviana (2005) Kempffiana, 1 (1), pp. 101-128Levington, A.E., McDiarmid, R., Moody, S., Nickerson, M., Rosado, J., Sokol, O., Voris, H., Museum acronyms (1980) Second edition, Herpetological Review, 11, pp. 93-102Lima, A.C., Pimenta, F.E., Reptilia, Squamata, Teiidae, Tupinambis longilineus: Distribution extension (2008) Check List, 4, pp. 240-243Manzani, P.R., Abe, A., A new species of Tupinambis Daudin, 1802 (Squamata: Teiidae) from Brazil (1997) Boletim do Museu Nacional, Nova Série, Zoologia, 382, pp. 1-10Manzani, P.R., Abe, A., Sobre dois novos métodos de preparação de hemipênis de serpentes (1988) Memórias do Instituto Butantan, 50 (1), pp. 15-20Manzani, P.R., Abe, A.S., A new species of Tupinambis Daudin, 1803 from southeastern Brazil (Squamata, Teiidae) (2002) Arquivos do Museu Nacional, Rio de Janeiro, 60, pp. 295-302Mesquita, D.O., Colli, G.R., França, F.G.R., Vitt, L.J., Ecology of a Cerrado lizard assemblage in the Jalapão region of Brazil (2006) Copeia 2006, (3), pp. 460-471. , doi: 10.1643/0045-8511(2006)2006[460:EOACLA]2.0.CO;2Moreira, L.A., Fenolio, D.B., Silva, H.L.R., Silva Jr., N.J., A preliminary list of the Herpetofauna from termite mounds of the cerrado in the Upper Tocantins river valley (2009) Papéis Avulsos de Zoologia, 49 (15), pp. 183-189. , http://www.scielo.br/scielo.php?pid=S0031-10492009001500001&script=sci_arttextMyers, C.H., Williams, E.E., McDiarmid, R.W., A new anoline lizard (Phenacosaurus) from the highland of Cerro de la Neblina, Southern Venezuela (1993) American Museum Novitates 3070, pp. 1-15Pesantes, O.S., A method for preparing the hemipenis of preserved snakes (1994) Journal of Herpetology, 28, pp. 93-95. , doi: 10.2307/1564686Recoder, R., Nogueira, C., Composição e diversidade de répteis na região sul do Parque Nacional Grande Sertão Veredas, Brasil Central (2007) Biota Neotropica, 7 (3), pp. 267-278. , doi: 10.1590/S1676-06032007000300029Recoder, R.S., Junior, M.T., Camacho, A., Nunes, P.M.S., Mott, T., Valdujo, P.H., Ghellere, J.M., Rodrigues, M.T., Répteis da Estação Ecológica Serra Geral do Tocantins, Brasil Central (2011) Biota Neotropica, 11 (1), pp. 263-282. , doi: 10.1590/S1676-06032011000100026Savage, J.M., On terminology for the description of the hemipenis of squamate reptiles (1997) Herpetological Journal, 7, pp. 23-25. , doi: 10.1590/S1984-46702011000400005Silva Jr., N.J., Silva, H.L.R., Rodrigues, M.T., Valle, N.C.U., Costa, M.C., Castro, S.P., Linder, E.T., Sites Jr., J.W., A fauna de vertebrados do vale do alto rio Tocantins em áreas de usinas hidrelétricas (2005) Estudos, 32, pp. 57-101Silveira, A.L., Reptilia, Squamata, Teiidae, Tupinambis quadrilineatus: Distribution extension and geographic distribution map (2009) Check List, 5 (3), pp. 442-445Taylor, J.F., Genus Tupinambis, Tegus (2003) Reptilia, 27, pp. 43-49Vitt, L.J., Cadwell, J.P., Colli, G.R., Garda, A.A., Mesquita, D.O., França, F.G.R., Shepard, D.B., Silva, V.N., Uma atualização do guia fotográfico dos répteis e anfíbios da região do Jalapão no Cerrado brasileiro (2005) Special Publications in Herpetology, San Noble Oklahoma Museum of Nature History, 2, pp. 1-24Werneck, F.P., Colli, G.R., The lizard assemblage from seasonally dry tropical forest enclaves in the Cerrado biome, Brazil, and its association with the pleistocenic arc (2006) Journal of Biogeography, 33, pp. 1983-1992. , doi: 10.1111/j.1365-2699.2006.01553.xZaher, H., Prudente, A.L.C., Hemipenis of Siphlophis (Serpentes, Xenodontinae) and Techniques of Hemipenial Preparation in Snakes: A Response to Dowling (2003) Herpetological Review, 34, pp. 302-30
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