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Search Results: 1 - 10 of 42642 matches for " Faustino;Ramírez-Rojas "
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Biocontrol de la pudrición de raíz de nochebuena de interior con Trichoderma spp. Root rot biocontrol for indoor poinsettia with Trichoderma spp.
Felipe de Jesús Osuna-Canizalez,María Félix Moreno-López,Faustino García-Pérez,Sergio Ramírez-Rojas
Revista mexicana de ciencias agrícolas , 2012,
Abstract: En Morelos, la pudrición de la raíz causada por Fusarium spp., es una de las principales enfermedades de la nochebuena de interior. Por su efecto devastador, en su prevención o control se realizan aplicaciones frecuentes de productos químicos, con los riesgos inherentes a la salud humana y al ambiente. En la búsqueda de alternativas bioracionales al manejo de esta enfermedad, se realizó un ensayo en el que se evaluaron tres cepas comerciales de Trichoderma spp., en tres diferentes sustratos: S1= "tierra de hoja" (70% v/v)+tezontle grueso (15% v/v)+tezontle fino (10% v/v)+agrolita (5% v/v); S2= turba (80% v/v)+ fibra de coco (20% v/v); S3= "tierra de hoja" (70%) + "tepojal" (30%), en las variedades comerciales más comunes, Freedom Red y Prestige Red. Se utilizó un dise o factorial de tratamientos 4 x 3 x 2 y los tratamientos resultantes se evaluaron en un dise o completamente al azar con seis repeticiones. Respecto a la incidencia de pudrición de la raíz, las cepas comerciales de Trichoderma spp., no mostraron diferencias entre sí ni con el testigo químico. La pudrición de la raíz estuvo asociada con S2, debido a una baja capacidad de aireación, y sólo se presentó en Prestige Red. La población (UFC g-1) de Trichoderma spp., en el sustrato al término del ciclo, fue igual (p< 0.05) entre cepas comerciales y entre estas y el testigo químico (sin inoculación), debido a la presencia de cepas nativas de Trichoderma en los componentes orgánicos de los sustratos ("tierra de hoja", turba y fibra de coco). In Morelos, root rot caused by Fusarium spp., is one of the main diseases of indoor poinsettia. In order to prevent or control its devastating effect, frequent applications of chemical products are performed, with inherent risks to human health and environment. In quest for alternative biorational options, an essay in which three commercial strains of Trichoderma spp., was done, in three different substrates: S1= "organic soil" (70% v/v)+thick tezontle (15% v/v)+thin tezontle (10% v/v)+agrolita (5% v/v); S2= peat moss (80% v/v)+ coconut fiber (20% v/v); S3= "organic soil" (70%)+"tepojal" (30%), in most common commercial varieties, Freedom Red and Prestige Red. A factorial design of 4 x 3 x 2 treatment was used and resulting treatments were evaluated in a completely random design with six repetitions. Regards root rot incidence, commercial strains of Trichoderma spp., did not show differences between them, either with chemical control. Root rot was associated with S2, due low aeration capacity, and only it was seen in Prestige Red. Population of Trichoderma spp.,
Biocontrol de la pudrición de raíz de nochebuena de interior con Trichoderma spp.
Osuna-Canizalez, Felipe de Jesús;Moreno-López, María Félix;García-Pérez, Faustino;Ramírez-Rojas, Sergio;Canul-Ku, Jaime;
Revista mexicana de ciencias agrícolas , 2012,
Abstract: in morelos, root rot caused by fusarium spp., is one of the main diseases of indoor poinsettia. in order to prevent or control its devastating effect, frequent applications of chemical products are performed, with inherent risks to human health and environment. in quest for alternative biorational options, an essay in which three commercial strains of trichoderma spp., was done, in three different substrates: s1= "organic soil" (70% v/v)+thick tezontle (15% v/v)+thin tezontle (10% v/v)+agrolita (5% v/v); s2= peat moss (80% v/v)+ coconut fiber (20% v/v); s3= "organic soil" (70%)+"tepojal" (30%), in most common commercial varieties, freedom red and prestige red. a factorial design of 4 x 3 x 2 treatment was used and resulting treatments were evaluated in a completely random design with six repetitions. regards root rot incidence, commercial strains of trichoderma spp., did not show differences between them, either with chemical control. root rot was associated with s2, due low aeration capacity, and only it was seen in prestige red. population of trichoderma spp.,(ufc g-1) in the substrate at end of cycle was the same (p< 0.05) between commercial strains and between them and the control (without inoculation), due presence of native strains of trichoderma in organic components of substrates ("organic soil", peat moss and coconut fiber).
A simple capacitor model for radio emission associated with earthquakes
Ares de Parga Gonzalo,Ramírez-Rojas Alejandro
中国物理 B , 2004,
Abstract: In this brief report we propose a simple model based on the properties of an electric capacitor under short-circuit conditions as a possible mechanism of radio emissions associated with earthquakes. This model can be considered as complementary to other models concerning the same problem.
Currency Substitution and Government Revenue from Inflation Currency Substitution and Government Revenue from Inflation
Mohsin S. Khan,C. Luis Ram?-rez-Rojas
Revista de Análisis Económico (RAE) , 1986,
Abstract: Currency Substitution and Government Revenue from Inflation The purpose of this paper is to show that in the case of an open economy the calculations of revenue-maximing rates of inflation have been made using a restrictive model that assumes that domestic residents can only substitute between domestic money and goods (and real assets). The paper demonstrates that once the effects of currency substitution, so common in developing countries, are taken into account, the inflation rate that maximizes the proceeds of the inflation tax can be quite lower than would be the case when currency substitution is ignored.
Multiscale entropy analysis of electroseismic time series
L. Guzmán-Vargas, A. Ramírez-Rojas,F. Angulo-Brown
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2008,
Abstract: In this work we use the multiscale entropy method to analyse the variability of geo-electric time series monitored in two sites located in Mexico. In our analysis we consider a period of time from January 1995 to December 1995. We systematically calculate the sample entropy of electroseismic time series. Important differences in the entropy profile for several time scales are observed in records from the same station. In particular, a complex behaviour is observed in the vicinity of a M=7.4 EQ occurred on 14 September 1995. Besides, we also compare the changes in the entropy of the original data with their corresponding shuffled version.
Entropy of geoelectrical time series in the natural time domain
A. Ramírez-Rojas,L. Telesca,F. Angulo-Brown
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2011, DOI: 10.5194/nhess-11-219-2011
Abstract: Seismic electric signals (SES) have been considered precursors of strong earthquakes, and, recently, their dynamics have been investigated within the Natural Time Domain (NTD) (Varotsos et al., 2004). In this paper we apply the NTD approach and the chaotic map signal analysis to two geoelectric time series recorded in a seismically very active area of Mexico, where two strong earthquakes, M=6.6 and M=7.4, occurred on 24 October 1993 and 14 September 1995, respectively. The low frequency geoelectric signals measured display periods with dichotomic behavior. Our findings point out to an increase of the correlation degree of the geoelectric signals before the occurrence of strong earthquakes; furthermore, the power spectrum and entropy in NTD are in good agreement with the results published in literature. Our results were validated by the analysis of a chaotic map simulated time series, which revealed the typical characteristics of artificial noise.
Possible dependence between the total solar irradiance and dimethylsulphide
Mendoza, B.;Flores-Márquez, E. L.;Ramírez-Rojas, A.;Martínez-Arroyo, A.;
Geofísica internacional , 2009,
Abstract: solar variability is one of the main natural influences on the earth's climate. biological processes are profoundly affected by the solar irradiance. some of these processes have been proposed to change the cloud albedo and therefore impact the climate. here we investigate the relation between the total solar irradiance (tsi) and the global concentration of dimethylsulphide (dms), produced by plancktonic algae in seawater. dms has been frequently mentioned as a forcing of climate through its effect on clouds and therefore on albedo. in the present work we attempt to find the relation between tsi and dms. we found that the tsi and the dms production data series display a correlation. a probabilistic scheme is introduced, the mutual information function (mif) which is a measure of the dependence between the parameters of interest. the mif seems to present solar cycle dependence: larger values during lower solar activity times (lower tsi times) than during higher solar activity epochs (higher tsi epochs). or in other words, the dependence between tsi and dms is stronger during lower solar activity times than during higher solar activity epochs.
A statistical analysis of electric self-potential time series associated to two 1993 earthquakes in Mexico
L. Flores-Márquez,J. Márquez-Cruz,A. Ramírez-Rojas,G. Gálvez-Coyt
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2007,
Abstract: Recent studies related with earthquake prediction involve statistical studies of the ground electric self-potential behavior. Published results about the complexity of this kind of processes encourage us to study the statistical behavior of the ground electric self-potential recorded in Guerrero state, Mexico. This region is characterized by high seismicity. The electric self-potential variations were recorded in the Acapulco station directly from the ground. The sampling period was four seconds and the data were stored from March to December of 1993. Two significant earthquakes (EQs) occurred near this station, 15 May and 24 October whose magnitudes were Mw=6.0 and Mw=6.6 respectively. A preliminary processing was carried out consisting of a moving average of the original time series in order to filter the very high frequencies and to complete short lacks of data and outliers. Then, a visual inspection of the complete filtered signal was performed to search some seismic electric signals (SES), which were ambiguously depicted. Subsequently, a detrending of μ=0 was applied with the windows of 3.3, 6.6 and 10 h. Later, the analysis of the spectral exponent β was made, showing changes during the total period examined, and the most evident changes occurred during the preparation mechanism of the Mw=6.6 EQ. Fifteen days before the 24 October EQ, a Brownian-noise like behavior was displayed (β≈2), having a duration of about two days. In addition a Higuchi fractal method and wavelet analysis were made confirming the presence of the β-anomaly.
Spectral and multifractal study of electroseismic time series associated to the Mw=6.5 earthquake of 24 October 1993 in Mexico
A. Ramírez-Rojas,A. Mu?oz-Diosdado,C. G. Pavía-Miller,F. Angulo-Brown
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2004,
Abstract: In this work we present a spectral and multifractal study of the electric self-potential fluctuations registered in an electroseismic station located at 100km from the epicenter of an earthquake (EQ) with Mw=6.5 in the Pacific coast of Mexico. Our study suggests that in general the time series analyzed displays a persistent behavior. Our results show an anticorrelation between the spectral exponent β and the width of the multifractal spectrum Δα, when they are calculated during a time interval of five months (four months before the EQ and one month after the EQ). In addition, we also calculate the time evolution of the correlation coefficient finding that it has a very similar behavior that the time evolution of Δα.
Statistical features of seismoelectric signals prior to M7.4 Guerrero-Oaxaca earthquake (México)
A. Ramírez-Rojas, E. L. Flores-Márquez, L. Guzmán-Vargas, G. Gálvez-Coyt, L. Telesca,F. Angulo-Brown
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2008,
Abstract: In this paper a statistical analysis of seismoelectric ULF signals prior to the M7.4 Guerrero-Oaxaca earthquake (EQ) occurred at the Mexican Pacific coast on 14 September 1995, has been performed. The signals were simultaneously recorded at three monitoring stations from the last months of 1994 until July of 1996. The nonlinear time series methods of Higuchi fractal dimension (HFD) and detrended fluctuation analysis (DFA) have been used. In the three data sets we found some complex dynamical behaviors that seemingly reflect a relaxation-EQ preparation-main shock-relaxation process. In particular, clear spike-like anomalies in both DFA- and HFD-exponents some months before the main shock are revealed.
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