Granma, Cuba

University of Granma
Granma, Cuba

The University of Granma is a university located in Bayamo, Cuba. Wikipedia.

Time filter
Source Type

Ramirez W.,University of Granma | Perez Y.M.,Laboratorio Of Diagnosticos Imv
Revista Electronica de Veterinaria | Year: 2017

Currently, pork production is a very important task due to the growth of the human population, its food needs with its diverse economic, technological, labor, professional, etc. implications. This led to the formulation of the following objectives: to evaluate the information contained in Model 623 Mortality and Outbreaks in Porcine from the period January 2005 to September 2015 in the categories of offspring, pre-breeds, others and totals by years, in a province of the eastern region of the country, as they appear declared. As the data did not correspond to what was established by Gaussian mathematics, in terms of normality and homogeneity of variance, the Wilcoxson test ,known as that of the scales, was applied. The document evaluated, does not provide all the elements related to its informational essence. It was concluded that the document does not include insufficiently explicit information (other types and specific motives) that are not always known in one of them. They their amounts and how they are distributed in the time and that they possess a condition of chance.

Millan H.,University of Granma | Cumbrera R.,University of Granma | Tarquis A.M.,Technical University of Madrid
Applied Mathematical Modelling | Year: 2016

Soil moisture distribution usually presents extreme variation at multiple spatial scales. A Levy stable model can assist multifractal analysis for a complete statistical characterization of such extreme variability. The objectives of the present work were (i) to characterize superficial soil moisture distribution patterns using a multifractal approach and (ii) to propose a 2D/3D model for estimating the Levy stable index from the multifractal distribution. Photographs (KodakTM EasyShare C182, 12 Mpx resolutions) were taken at three different times of soil wetting process after soil irrigation (e.g., 5, 10 and 20 min.). ImageJ Software was used for image processing and multifractal analysis. Levy stable index, μ, was estimated from the f(α) curve using a 2D extension of a previous model. All gray scale images were approximately bimodal. Multifractal analysis showed that D0 was consistently <2, which gives evidence on the fractal structure of the support. All the investigated soil moisture distributions fitted well the multifractal log-Levy stable model with stability index within the range 1 < μ < 2 and Hurst exponent (H) 0.5 < H < 1. This implies that soil moisture pattern can be described by sub-Gaussian statistics (e.g., far from Central Limit Theorem) and it can arise as the outcome of persistence due to long memory effects. The results could be useful for improving the statistical characterization and the predictive capability of future models related to spatially variable soil processes. © 2015.

Soria-Lorente A.,University of Granma | Soria-Lorente A.,Catholic University of Temuco | Berres S.,Catholic University of Temuco
Security and Communication Networks | Year: 2017

This contribution proposes a novel steganographic method based on the compression standard according to the Joint Photographic Expert Group and an Entropy Thresholding technique.The steganographic algorithm uses one public key and one private key to generate a binary sequence of pseudorandom numbers that indicate where the elements of the binary sequence of a secret message will be inserted.The insertion takes eventually place at the first seven AC coefficients in the transformed DCT domain. Before the insertion of the message the image undergoes several transformations. After the insertion the inverse transformations are applied in reverse order to the original transformations.The insertion itself takes only place if an entropy threshold of the corresponding block is satisfied and if the pseudorandom number indicates to do so.The experimental work on the validation of the algorithm consists of the calculation of the peak signal-to-noise ratio (PSNR), the difference and correlation distortionmetrics, the histogram analysis, and the relative entropy, comparing the same characteristics for the cover and stego image. The proposed algorithm improves the level of imperceptibility analyzed through the PSNR values. A steganalysis experiment shows that the proposed algorithmis highly resistant against the Chi-square attack. © 2017 A. Soria-Lorente and S. Berres.

Ghanbarian-Alavijeh B.,University of Tehran | Ghanbarian-Alavijeh B.,Wright State University | Millan H.,University of Granma | Huang G.,China Agricultural University
Canadian Journal of Soil Science | Year: 2011

The soil water retention curve is an important hydraulic parameter for characterizing water flow and contaminant transport in porous media. Therefore, many empirical, semi physical, and physical models of the soil water retention curve have been proposed. Among them, fractal models appear to be a useful approach for modeling soil as a heterogeneous porous medium and its hydraulic characteristics. Fractal models are mathematically based, and their parameters have physical meanings. In this study, we review published fractal, prefractal and pore-solid-fractal models for soil water retention curves including Tyler and Wheatcraft, Rieu and Sposito, Perrier et al., Perfect, Bird et al., Millán and González-Posada, and Cihan et al. models. In the pore-solid fractal (PSF) approach the pore phase and matrix phase have a finite volume even for an infinite number of iterations. The results of fitting the PSF model to measured soil water retention data indicate that this model works well, particularly at lower water contents.

Govea-Alcaide E.,University of Granma | Machado I.F.,University of Sao Paulo | Jardim R.F.,University of Sao Paulo
Journal of Applied Physics | Year: 2015

Pre-reacted powders of (Bi-Pb)2Sr2Ca2Cu3O10+ δ (Bi-2223) were consolidated by using the spark plasma sintering (SPS) technique under vacuum and at two different temperatures TD: 750 and 830 °C. The results indicate the occurrence of grains with core-shell morphology, where the shell is oxygen deficient. A post-annealing heat treatment (PAHT), performed in air, at 750 °C, and for a brief time interval, is responsible for a 10 to 25-fold increase in the transport superconducting current density at 77 K. The role of the oxygen-deficient shell, before and after the PAHT, was investigated by means of magnetic and transport measurements. We argue that the PAHT is two folds: (i) it is responsible for the decrease of the width of the oxygen-deficient shell, then increasing the oxygen content along the grain boundaries; (ii) it promotes the formation of conduction current paths along the grain boundaries of the SPS material. © 2015 AIP Publishing LLC.

Millan H.,University of Granma | Ghanbarian-Alavijeh B.,University of Tehran | Garcia-Fornaris I.,University of Granma
Atmospheric Research | Year: 2010

Chaos theory and its applications are at the cutting edge of investigations in environmental sciences (e.g. Environmental Physics, Biometeorology and Atmospheric Sciences among many others). However, we still need to take advantage of some recent computational efforts for nonlinear investigations of empirical meteorological variables. The objectives of this work were (i) to quantify the nonlinear variability of observed time series of mean daily temperature and dewpoint records collected at Babolsar, Iran and (ii) to stimulate the use of recent computational tools for investigating environmental data. Positive Lyapunov exponents were found for both time series (λmax=0.0174 and λmax=0.0169 for mean daily air temperature and dewpoint temperature, respectively). In addition, determinism tests showed that both time series masked strong determinist components (|→k|=0.721 and |→k|=0.693 for mean daily temperature and dewpoint, respectively). That nonlinear test could be of use in future research for making decisions in applying deterministic, stochastic or combinations of both models with climate data. There were found interesting evidences on the existence of empirical attractors in univariate climate time series as expressed by reconstructing both phase spaces. © 2010 Elsevier B.V.

Ghanbarian-Alavijeh B.,University of Tehran | Ghanbarian-Alavijeh B.,Wright State University | Millan H.,University of Granma
International Agrophysics | Year: 2010

Soil water retention curve (SWRC) is one of the most important soil hydraulic properties, whose estimation is still under consideration. In this study, we used 315 soil samples from the UNSODA database to develop three models of point pedotransfer functions (PTFs) and to verify them. We also used an independent database, GRIZZLY, with 59 samples, to verify the developed point PTFs and to compare them with the Rosetta model. Multiple linear regression and stepwise methods were used to derive pedotransfer functions. In the first model, soil texture data ie sand, silt, and clay content, geometric mean particle-size diameter and geometric standard deviation as well as bulk density were used to develop point PTFs at 10 matric potentials. In the second model, water content at field capacity, and in the third model water content at field capacity and permanent wilting point were also used for developing PTFs at 9 and 8 matric potentials, respectively. To evaluate the accuracy and reliability of the point PTFs, we used crossvalidation eg repeated random splitting of the data set into subsets for development and validation. The calculated RMSE values showed that all three developed point PTFs estimated soil water retention curve better than the Rosetta model. © 2010 Institute of Agrophysics, Polish Academy of Sciences.

Millan H.,University of Granma | Tarquis A.M.,Technical University of Madrid | Perez L.D.,University of Granma | Mato J.,University of Granma | Gonzalez-Posada M.,University of Granma
Soil and Tillage Research | Year: 2012

Spatial variability of Vertisol properties is relevant for identifying those zones with physical degradation. In this sense, one has to face the problem of identifying the origin and distribution of spatial variability patterns. The objectives of the present work were (i) to quantify the spatial structure of different physical properties collected from a Vertisol, (ii) to search for potential correlations between different spatial patterns and (iii) to identify relevant components through multivariate spatial analysis. The study was conducted on a Vertisol (Typic Hapludert) dedicated to sugarcane (Saccharum officinarum L.) production during the last sixty years. We used six soil properties collected from a squared grid (225 points) (penetrometer resistance (PR), total porosity, fragmentation dimension (D f), vertical electrical conductivity (ECv), horizontal electrical conductivity (ECh) and soil water content (WC)). All the original data sets were z-transformed before geostatistical analysis. Three different types of semivariogram models were necessary for fitting individual experimental semivariograms. This suggests the different natures of spatial variability patterns. Soil water content rendered the largest nugget effect (C 0=0.933) while soil total porosity showed the largest range of spatial correlation (A=43.92m). The bivariate geostatistical analysis also rendered significant cross-semivariance between different paired soil properties. However, four different semivariogram models were required in that case. This indicates an underlying co-regionalization between different soil properties, which is of interest for delineating management zones within sugarcane fields. Cross-semivariograms showed larger correlation ranges than individual, univariate, semivariograms (A≥29m). All the findings were supported by multivariate spatial analysis, which showed the influence of soil tillage operations, harvesting machinery and irrigation water distribution on the status of the investigated area. © 2011 Elsevier B.V..

An interpretive methodological approach and elements of the research-action method were used in this research that shows the results of a study made with a group of families from Bayamo city which have a five years old or younger child with Down Syndrome (DS), with the objective of characterizing the significance of their birth. A purposeful and intensive, typical case sampling was chosen; 14 fathers and mothers were interviewed, 10 of them participated in the sessions of a Formative Group, guided by one coordinator and two observers, supervised by an expert in the planning, implementation and analysis of the intervention. The emergent topics detected aimed to the significance that has in the family the birth of a Down syndrome child; in the Formative Group some of these aspects and the difficulties in the functioning of the family were approached; the group reflection facilitated the incorporation of new analysis, cognitive and affective elements for the initiation of change processes in these families. Diagnostic Indicators of population, which according to their diagnostic and predictive importance, can be used in the design of other similar programs for community intervention linked to the Primary Health Care, Education, Community Extension among other, were identified, which is one of the most important value of this research.

Perez L.D.,University of Granma | Millan H.,University of Granma | Gonzalez-Posada M.,University of Granma
Soil and Tillage Research | Year: 2010

Sugarcane is one important crop for many Third World countries. Soils dedicated to sugarcane are usually compacted during the harvesting process. The main objective of the present work was to search for prefractal scaling patterns of soil compaction before and after sugarcane harvest. We used descriptive statistics and prefractal analysis with experimental semivariograms for characterizing the spatial patterns of soil penetrometer resistance distributions. The soil is a Vertisol (Typic Hapludert) dedicated to sugarcane production during the last 60 years. Approximately 50% of soil resistance values were over 2.5 MPa after sugarcane harvest. This could restrict sugarcane shoot emergence. A power-law (prefractal) model fitted experimental semivariograms fairly well except for those distributions corresponding to 2.5-5.0 cm soil depth. Those particular distributions could be fitted by any standard geostatistical model. The main findings were (i) scaling exponents larger than 1.5 which indicate anti-persistence and (ii) change of anisotropic directions after sugarcane harvest. The range of prefractal behaviour was approximately 105m before harvest and 93. m after crop harvest. The spatial structure of some soil physical or mechanical properties connected to soil compaction can resemble those patterns. The combination of Geostatistics and prefractal analysis can assist the mechanized agriculture and scientists through a previous identification of degraded zones within the field and the physical processes involved in the formation of those local areas. © 2010 Elsevier B.V.

Loading University of Granma collaborators
Loading University of Granma collaborators