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| Registros recuperados: 35 | |
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| Horng, Cs; Roberts, Ap; Liang, Wt. |
| We present a 2.14-Myr astronomically tuned relative geomagnetic paleointensity record from the western Philippine Sea. Pseudosingle-domain titanomagnetite is the only magnetic mineral identified and variations in titanomagnetite concentration fall well within the accepted limits for relative paleointensity variations. No significant temporally persistent periodicities are observed in wavelet analyses of the paleointensity time series or in the rock magnetic parameters used for relative paleointensity normalization. This suggests that our paleointensity record is largely free of rock magnetic or lithological artefacts and that it represents a reliable record of geomagnetic behavior with no evidence for modulation of the field at Earth orbital periods. The... |
| Tipo: Text |
Palavras-chave: Geomagnetic paleointensity; Magnetostratigraphy; Spectral analysis; Wavelet analysis; Philippine Sea. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/00224/33554/31978.pdf |
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| Campbell,Patrícia Morais da Matta; Fernandes Filho,Elpídio Inácio; Francelino,Márcio Rocha; Demattê,José Alexandre Melo; Pereira,Marcos Gervasio; and,Clécia Cristina Barbosa Guimarães; Pinto,Luiz Alberto da Silva Rodrigues. |
| ABSTRACT Quantification of soil properties is essential for better understanding of the environment and better soil management. The conventional techniques of laboratory analysis are sometimes costly and detrimental to the environment. Thus, development of new techniques for soil analysis that do not generate residues, such as spectroscopy, is increasingly necessary as a viable way to estimate a wide range of soil properties. The objective of this study was to predict the levels of organic carbon (OC), clay, and extractable phosphorus (P), from the spectral responses of soil samples in the visible and near infrared (Vis-NIR), medium infrared (MIR), and Vis-NIR-MIR using different preprocessing methods combined with five prediction models. Soil samples were... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Spectral analysis; Reflectance; Chemometrics. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832018000100314 |
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| Lin, Jing-yi; Sibuet, Jean-claude; Hsu, S. |
| The acoustic basement map of the East China Sea, established by the Shanghai Offshore Petroleum Bureau with all available industry seismic data, shows the existence of a 30-km-wide, 10-km-deep basin, that we named the Ho Basin. The Ho Basin belongs to a series of elongated deep basins extending over 600 km east of the Taiwan-Sinzi Ridge and flanked to the East by a ridge named the Longwan Ridge in its northern part. This new system of basin and ridge was probably formed during middle Miocene, sometimes in between rifting episodes occurring in the Taipei Basin and Okinawa Trough. It. complements the already defined system of five belts of back-arc basins and associated arc volcanic ridges in the East China Sea, which are progressively younger from the... |
| Tipo: Text |
Palavras-chave: Depth of magnetic sources; Spectral analysis; Backarc basins; East China Sea. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-1342.pdf |
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| Huber,D.A.; Carmo,J.M. do; Castania,J.A.; Fazan Jr,R.; Salgado,H.C.. |
| Because it is not known where in the reflex arch, i.e., afference, central nervous system or efferences, hyperglycemia affects baroreflex function, the present study examined the effect of short-term (30 min) hyperglycemia on aortic depressor nerve function measured by a mean arterial pressure vs aortic depressor nerve activity curve, fitted by sigmoidal regression, or by cross-spectral analysis between mean arterial pressure and aortic depressor nerve activity. Anesthetized male Wistar rats received an intravenous bolus (0.25 mL) injection, followed by 30 min of infusion (1 mL/h) of 30% glucose (N = 14). Control groups received a bolus injection and infusion of 0.9% saline (N = 14), or 30% mannitol (N = 14). Glucose significantly increased both blood... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Pressoreceptors; Hyperglycemia; Arterial pressure; Spectral analysis. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2007001100017 |
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| Letson, David; McCullough, B.D.. |
| In this paper we seek to characterize the robustness of the ENSO/soybean price relationship and to determine whether it has practical economic content. If such a meaningful relationship exists, the implications could be profound for commodity traders and for public sector investments in climate forecasting capabilities. Also, the validity of economic evaluations of climate impacts and climate forecasts based on ENSO-price independence would come into question. Our findings suggest a relationship between interannual climate and soybean prices, although we are not able to attribute the relationship to ENSO or to say the ENSO is economically important. |
| Tipo: Journal Article |
Palavras-chave: Climate forecasting; Granger causality; Spectral analysis; SOI; SST; Resource /Energy Economics and Policy; C22; Q11. |
| Ano: 2001 |
URL: http://purl.umn.edu/15443 |
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| Royer, Francois; Fromentin, Jean-marc. |
| This paper provides an exploratory analysis aiming to seek whether the colour of environmental noise theory could help in understanding the intriguing reproductive strategy of Atlantic bluefin tuna (BFT). A frequency-based approach based on spectral exponents, f(beta) with beta < 0, is chosen and applied on 10 biogeographical provinces covering the North Atlantic. The major BFT spawning area, i.e. the Mediterranean Sea, was the only one to display a pink power spectrum, whereas open ocean regions displayed more reddened fluctuations, i.e. greater variance at low frequencies. Environmental noise in the Mediterranean could, thus, offer more favourable characteristics on the long-term than the open ocean. The implications of these findings are discussed in... |
| Tipo: Text |
Palavras-chave: Thunnus thynnus; Spectral analysis; Spawning; Sea surface temperature; Environmental noise. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2437.pdf |
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| Vieira,T.M.M.; Oliveira,L.F.; Nadal,J.. |
| Even though frequency analysis of body sway is widely applied in clinical studies, the lack of standardized procedures concerning power spectrum estimation may provide unreliable descriptors. Stabilometric tests were applied to 35 subjects (20-51 years, 54-95 kg, 1.6-1.9 m) and the power spectral density function was estimated for the anterior-posterior center of pressure time series. The median frequency was compared between power spectra estimated according to signal partitioning, sampling rate, test duration, and detrending methods. The median frequency reliability for different test durations was assessed using the intraclass correlation coefficient. When increasing number of segments, shortening test duration or applying linear detrending, the median... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Center of pressure; Spectral analysis; Quiet standing; Estimators; Median frequency. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009000700012 |
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| Martínez, R.. |
| Usando series de tiempo de promedios diarios de presión atmosférica, temperatura ambiental, temperatura superficial y nivel medio del mar en los años 1994-1995 en cinco estaciones costeras de Ecuador y Colombia y una estación en las Islas galápagos (Ecuador) se aplicaron las técnicas del análisis espectral para determinar las oscilaciones existentes en el océano y la atmósfera. Se obtuvieron con alto niveles de coherencia, cinco modos predominantes en la atmósfera tropical: la oscilación de 37 días, muy próxima a la oscilación de Madden-Julian (1972), un modo de tres semanas con características de la " autooscilación" de 21 días, Murakami, 1974 y que es de naturaleza planetaria, una tercera oscilación de 17 días, de características muy similares a la onda... |
| Tipo: Journal Contribution |
Palavras-chave: Barotropic motion; Water waves; Spectral analysis; Time series; Oceanographic data; Fixed stations; Water temperature data; Air temperature; Atmospheric pressure; Mean sea level; Atmospheric pressure; Spectral analysis; Air temperature; Http://aims.fao.org/aos/agrovoc/c_693; Http://aims.fao.org/aos/agrovoc/c_28964; Http://aims.fao.org/aos/agrovoc/c_230. |
| Ano: 1998 |
URL: http://hdl.handle.net/1834/2199 |
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| Kunz,V.C.; Borges,E.N.; Coelho,R.C.; Gubolino,L.A.; Martins,L.E.B.; Silva,E.. |
| The objectives of this study were to evaluate and compare the use of linear and nonlinear methods for analysis of heart rate variability (HRV) in healthy subjects and in patients after acute myocardial infarction (AMI). Heart rate (HR) was recorded for 15 min in the supine position in 10 patients with AMI taking β-blockers (aged 57 ± 9 years) and in 11 healthy subjects (aged 53 ± 4 years). HRV was analyzed in the time domain (RMSSD and RMSM), the frequency domain using low- and high-frequency bands in normalized units (nu; LFnu and HFnu) and the LF/HF ratio and approximate entropy (ApEn) were determined. There was a correlation (P < 0.05) of RMSSD, RMSM, LFnu, HFnu, and the LF/HF ratio index with the ApEn of the AMI group on the 2nd (r = 0.87, 0.65,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Myocardial infarction; Heart rate variability; Autonomic nervous system; Spectral analysis; Nonlinear dynamics. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2012000500011 |
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| Vilibic, I; Leder, N. |
| The aim of this paper is to investigate long-period climatic variations in the Mediterranean sea level, as well as some meteorological parameters and the influence of atmospheric forcing on sea-level fluctuations. Data for the annual mean sea level at seven stations (Trieste, Genoa, Marseilles, Alicante, Oran, La Goulette and Sfax), located in the Western Mediterranean, together with mean air pressure and temperature data for Zagreb, have been spectrally analysed. Various peaks in the power, coherence and phase spectra have been detected. The period of about 5.1 years corresponds to the quasi-meridional fluctuation in the paths of Atlantic cyclones. The period of about 2.7 years may be excited by variations of currents and sea-surface temperature in the... |
| Tipo: Text |
Palavras-chave: Sea-level series; Meteorological series; Spectral analysis; Long-period climatic oscillations. |
| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/00096/20763/18389.pdf |
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| Registros recuperados: 35 | |
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