242 research outputs found
Coding of information into video file
In this work we propose an algorithm for hiding information in an avi file. The avi file is splitted into its audio and video components. The audio is saved in a file and its parameters are not changed. In addition, the video is splitted into frames. The frame contains 24 images which are transformed by Discrete Wavelet Transform (DWT). By appliying the DWT we obtain four sub images each one with different band width. Once we have the frequencies splitted, places are chosen for hiding information. In this work the concealment is made inside another avi file. However, the procedure can be applied for any kind of information. The file to be hidden is splitted into audio and video. Both are concealed independently in the sub images from the original video. The video to be hidden is separated into its frequency components and only the lower ones are saved, while the others are deleted. The compressed version of the image to be concealed is inserted into the video’s sub images. Once the concealment has been done the Inverse Discrete Wavelet Transform (IDWT) is applied and the video is reconstructed again. To get the hidden information the same insertion process is made, and it applies the IDWT in the recover file
Mortalidad bovina en la altillanura del Vichada
Recoge en forma resumida, los aspectos más relevantes encontrados por los autores, en una investigación realizada en la altillanura del Vichada, entre Santa Rosalia y Puerto Carreño, en hatos con ganadería bovina extensiva-extractiva, denominada: diagnóstico y alternativas de control al problema de la mortalidad bovina en un área del Vichada. Los predios estudiados se ubicaron a un máximo de 10 km del río Meta, se tomarón muestras de suelos como también de forraje de sabana nativa, adicionalmente muestras de sangre de la población bovina. Los resultados mostraron suelos con altos contenidos de Al intercambiable, Fe y Mn, fuertemente ácidos y con bajos contenidos de P, K y Ca. El contenido promedio foliar de N estuvo entre 0.74 y 0.94 por ciento equivalente a un valor de 4.68 y 5.88 por ciento de proteína cruda. El porcentaje de Ca, P y Mg fué de 0.19 y 0.15 por ciento en materia seca, los elementos que presentaron amplia variabilidad fueron B, Fe, K, Mn, P y Cu. Los valores medios de proteína cruda, fibra detergente netro de degradabilidad insitu de la materia seca fueron 5.28 , 62 y 46 por ciento. El decrecimiento paulatino de las concentraciones de minerales en forrajes se sabana, manejadas bajo quema, es notorio a medida que aumenta la edad del rebrote. Los valores de química sérica y hematología muestran alta variación en fósforo sérico, hierro, globulina, hemoglobina corpuscular media y glóbulos blancos lo que manifiesta una leucopenia posiblemente ocasionada por recirculación de poblaciones virales, hematozoos, subnutrición o agentes inmunodepresores. Esta investigación contribuye a entender la situación como de origen multicausal, donde la subnutrición continuada, es quizá la causa principal que predispone un mayor riesgo de enfermedad, lento desarrollo corporal, ineficiencia reproductiva y mortalidadGanadería bovin
Origen geno-geográfico de haplotipos STR del cromosoma Y en una muestra caucásico-mestiza y afrodescendiente de Colombia
Introduction: Y chromosome STR haplotypes have been widely used in population studies to establish the origin of diverse populations.Objective: We analyzed Y chromosome STR haplotypes (8 loci) in 134 Caucasian-mestizo and 137 African-descent Colombian unrelated individuals to correlate the geographical origin with historical data as well as the genetic relationships and possible admixture patterns.Materials and methods: One hundred samples of African descent and 137 Caucasian-mestizo samples analyzed for Y chromosome STR haplotypes by PCR followed by acrylamide electrophoresis.Results: No evidence of population substructure was found for the African descent. Two point fiftynine per cent of the haplotypes were shared between the two groups with the possible existence of Caucasian gene flow towards Afro-descendants.Conclusion: The Caucasian-Mestizo Colombian population is grouped with other populations of the Iberian Peninsula and Europe, while the Afro-Colombian population is grouped with other African populations reported. doi: http://dx.doi.org/10.7705/biomedica.v33i3.807 Introducción. Los haplotipos STR de cromosoma Y han sido ampliamente utilizados en estudios de poblaciones para establecer el origen de diversas poblaciones.Objetivo. Se analizaron haplotipos STR del cromosoma Y (8 loci) en 134 afrodescendientes y caucásico-mestizos no relacionados de Colombia, para correlacionar el origen geográfico con los datos históricos, así como las relaciones genéticas y posibles patrones de mezcla.Materiales y métodos. Se analizaron los haplotipos STR del cromosoma Y mediante PCR seguidas de electroforesis en acrilamida, de 134 muestras de afrodescendientes y 137 muestras de caucásicos mestizos.Resultados. No se encontró evidencia de subestructuración de la población afrodescendiente. El 2,59 % de los haplotipos eran compartidos en los dos grupos analizados, con la posible existencia deflujo génico de caucásico-mestizos hacia los afrodescendientes.Conclusión. La población caucásico-mestiza colombiana se agrupa con otras poblaciones de la península Ibérica y Europa, mientras que la población afrodescendiente colombiana se agrupa conotras poblaciones africanas reportadas. doi: http://dx.doi.org/10.7705/biomedica.v33i3.80
Incidence of Dementia in Elderly Latin Americans: Results of the Maracaibo Aging Study
Introduction—There are few longitudinal studies of dementia in developing countries. We used longitudinal data from the Maracaibo Aging Study (MAS) to accurately determine the age- and sex-specific incidence of dementia in elderly Latin Americans.
Methods—The DSM IV-R was used to diagnose dementia, which was classified as Alzheimer’s disease (AD), vascular dementia (VaD), or other. Age- and sex-specific incidence was estimated as the number of new cases of dementia divided by person-years of follow-up (p-y).
Results—The incidence of all dementia diagnoses was 9.10 per 1000 p-y (95% CI 7.13–11.44; 8026 total p-y), 5.18 for AD (95% CI 3.72–7.03; 7916 total p-y), and 3.35 for VaD (95% CI 2.19–4.91; 7757 total p-y).
Discussion—Among MAS participants under 65 years of age, the incidence of dementia was higher than that of US whites. Among individuals over 65 years of age, the incidence was comparable to the mean of previous incidence estimates for other populations worldwide
Serum tryptase monitoring in indolent systemic mastocytosis: association with disease features and patient outcome
This is an open-access article distributed under the terms of the Creative Commons Attribution License.-- et al.[Background]: Serum baseline tryptase (sBT) is a minor diagnostic criterion for systemic mastocytosis (SM) of undetermined prognostic impact. We monitored sBT levels in indolent SM (ISM) patients and investigated its utility for predicting disease behaviour and outcome. [Methods]: In total 74 adult ISM patients who were followed for ≥48 months and received no cytoreductive therapy were retrospectively studied. Patients were classified according to the pattern of evolution of sBT observed. [Results]: Overall 16/74 (22%) cases had decreasing sBT levels, 48 (65%) patients showed increasing sBT levels and 10 (13%) patients showed a fluctuating pattern. Patients with significantly increasing sBT (sBT slope ≥0.15) after 48 months of follow-up showed a slightly greater rate of development of diffuse bone sclerosis (13% vs. 2%) and hepatomegaly plus splenomegaly (16% vs. 5%), as well as a significantly greater frequency of multilineage vs. mast cells (MC)-restricted KIT mutation (p = 0.01) together with a greater frequency of cases with progression of ISM to smouldering and aggressive SM (p = 0.03), and a shorter progression-free survival (p = 0.03). [Conclusions]: Monitoring of sBT in ISM patients is closely associated with poor prognosis disease features as well as with disease progression, pointing out the need for a closer follow-up in ISM patients with progressively increasing sBT values.This work was supported by grants from the Fondo de Investigaciones Sanitarias (FIS) of the Ministerio de Ciencia e Innovación of Spain (RETICS RD06/0020/0035-FEDER and PS09/00032); Fundación Sociosanitaria de Castilla-La Mancha (FISCAM 2007/36, FISCAM 2010/008 and G-2010/C-002); Instituto de Salud Carlos III of the Ministerio de Economía y Competitividad of Spain (PI11/02399); Junta de Castilla y León (SAN/103/2011); Fundación Ramón Areces; Fundación Española de Mastocitosis (FEM 2010); Hospital Virgen de la Salud Biobank (BioB-HVS) supported by grant of RETICS RD09/0076/00074, (Toledo, Spain).Peer Reviewe
Using a Floating-Gate MOS Transistor as a Transducer in a MEMS Gas Sensing System
Floating-gate MOS transistors have been widely used in diverse analog and digital applications. One of these is as a charge sensitive device in sensors for pH measurement in solutions or using gates with metals like Pd or Pt for hydrogen sensing. Efforts are being made to monolithically integrate sensors together with controlling and signal processing electronics using standard technologies. This can be achieved with the demonstrated compatibility between available CMOS technology and MEMS technology. In this paper an in-depth analysis is done regarding the reliability of floating-gate MOS transistors when charge produced by a chemical reaction between metallic oxide thin films with either reducing or oxidizing gases is present. These chemical reactions need temperatures around 200 °C or higher to take place, so thermal insulation of the sensing area must be assured for appropriate operation of the electronics at room temperature. The operation principle of the proposal here presented is confirmed by connecting the gate of a conventional MOS transistor in series with a Fe2O3 layer. It is shown that an electrochemical potential is present on the ferrite layer when reacting with propane
Modelos potenciales de distribución geográfica y climática del complejo Amblyomma cajennense (Acari: Ixodidae), potencial vector de Rickettsia rickettsii en Colombia
Introduction: The species of the Amblyoma cajennense complex, potential vectors involved in the transmission of Rickettsia rickettsii in Central and South America, have a wide geographical distribution in the Neotropics. In Colombia, the knowledge about these species, their distribution, and many aspects of their ecology is still limited.Objective: To explore the ecology of A. cajennense complex in Colombia based on the study of its habitat selection, as well as the generation of potential geographic and climatic distribution models.Materials and methods: We used unique records of these ticks to study the selection patterns of the climatic habitat using the Ecological Niche Factor Analysis (ENFA), and we built distribution models using the MaxEnt and GARP algorithms.Results: The record of distributions showed that A. cajennense complex is present in all five natural regions of Colombia with 64.71% of the records found in the departments of Antioquia, Cundinamarca, and Huila. The analysis of their habitat selection showed that these ticks preferably select geographical areas (ENFA: 96.03%) according to the isothermality conditions and the precipitation of the driest quarter of the year. The potential distribution models indicated habitat suitability in 31 to 51% of the area of the country depending on the algorithm.Conclusions: The distribution of A. cajennense complex in Colombia is highly influenced by a climatebased habitat selection, a characteristic that favored the creation of distribution models. Field studies will allow the validation of the potential distribution models and further genetic studies will be required in the country to identify species within the complex and study their potential hybridization areas.Introducción. Las especies del complejo Amblyomma cajennense, potenciales vectores implicados en la transmisión de Rickettsia rickettsii en Centroamérica y Suramérica, presentan una amplia distribución geográfica en el neotrópico. En Colombia, todavía es incipiente el conocimiento sobre las especies de este complejo, su distribución y su ecología.Objetivo. Explorar la ecología del complejo A. cajennense en Colombia a partir del estudio de su selección de hábitat y la generación de modelos potenciales de distribución geográfica y climática.Materiales y métodos. Se utilizaron registros únicos de la presencia de estas garrapatas en el estudio de sus patrones de selección del hábitat, mediante el análisis factorial del nicho ecológico (Ecological Niche Factor Analysis, ENFA), y se construyeron modelos de distribución potencial con las metodologías MaxEnt y GARP.Resultados. El complejo A. cajennense se encontró en las cinco regiones naturales de Colombia, con 64,71 % de los registros procedentes de los departamentos de Antioquia, Cundinamarca y Huila. La selección del hábitat evidenció que estas garrapatas escogen preferentemente las áreas geográficas (ENFA: 96,03 %) según sus condiciones de índice de estabilidad térmica y de precipitación en el trimestre más seco del año. Los modelos de distribución potencial indicaron la idoneidad del hábitat en 31 a 51 % del área del país dependiendo del algoritmo empleado.Conclusiones. En Colombia, el complejo A. cajennense presenta una distribución muy influenciada por el comportamiento en la selección del hábitat climático, característica que facilitó la creación de modelos de distribución. En futuros estudios de campo, se podrían validar los modelos presentados; se requieren, además, otros estudios genéticos para la identificación de especies del complejo y el manejo de sus potenciales zonas de hibridación en el país
Transcriptional Profiles of California Sea Lion Peripheral NK and CD+8 T Cells Reflect Ecological Regionalization and Infection by Oncogenic Viruses
The California sea lion is one of the few wild mammals prone to develop cancer, particularly urogenital carcinoma (UGC), whose prevalence is currently estimated at 25% of dead adult sea lions stranded along the California coastline. Genetic factors, viruses and organochlorines have been identified as factors that increase the risk of occurrence of this pathology. Given that no cases of UGC have as yet been reported for the species along its distribution in Mexican waters, the potential relevance of contaminants for the development of urogenital carcinoma is highlighted even more as blubber levels of organochlorines are more than two orders of magnitude lower in the Gulf of California and Mexican Pacific than in California. In vitro studies have shown that organochlorines can modulate anti-viral and tumor-surveillance activities of NK and cytotoxic T-cells of marine mammals, but little is known about the activity of these effectors in live, free-living sea lions. Here, we examine leukocyte transcriptional profiles of free-ranging adult California sea lions for eight genes (Eomes, Granzyme B, Perforin, Ly49, STAT1, Tbx21, GATA3, and FoxP3) selected for their key role in anti-viral and tumor-surveillance, and investigate patterns of transcription that could be indicative of differences in ecological variables and exposure to two oncogenic viruses: sea lion type one gammaherpesvirus (OtHV-1) and sea lion papillomavirus type 1 (ZcPV-1) and systemic inflammation. We observed regional differences in the expression of genes related to Th1 responses and immune modulation, and detected clear patterns of differential regulation of gene expression in sea lions infected by genital papillomavirus compared to those infected by genital gammaherpesvirus or for simultaneous infections, similar to what is known about herpesvirus and papillomavirus infections in humans. Our study is a first approach to profile the transcriptional patterns of key immune effectors of free-ranging California sea lions and their association with ecological regions and oncogenic viruses. The observed results add insight to our understanding of immune competence of marine mammals, and may help elucidate the marked difference in the number of cases of urogenital carcinoma in sea lions from US waters and other areas of their distribution
Cardiovascular risk in a teenage population in Timbío, Colombia
Introducción: Las enfermedades cardiovasculares se encuentran entre las primeras causas de muerte a nivel mundial y la evidencia científica sugiere que tienen un origen en edades tempranas, por lo que disminuir desde la adolescencia los riesgos que contribuyen a su aparición es indispensable. Objetivo: Determinar riesgo cardiovascular en la población adolescente de una institución educativa de Timbío, Cauca, 2015 – 2016. Metodología: Estudio cuantitativo, descriptivo, observacional y de corte transversal. Muestra: 100 estudiantes (47 mujeres, 53 hombres), de 10 a 19 años de edad. Se evaluaron variables sociodemográficas, antropométricas, fisiológicas, bioquímicas (glicemia), antecedentes personales, familiares, estilos de vida y uso de anticonceptivos orales. Resultados: Se encontró una mayor prevalencia de riesgo cardiovascular en el grupo etario adolescente (15-18 años) con 84.6%; el género femenino presentó más posibilidad de tener riesgo cardiovascular (OR: 2.8, IC 95% 1.17 – 6.87); el 7% afirmó consumir tabaco regularmente y el 12% son fumadores pasivos. Se obtuvo que el 26% ingiere bebidas alcohólicas, con una mayor prevalencia entre las edades de 15 a 18 años (OR: 19.4, IC 95% 2.45 – 48.11); en cuanto a la actividad física el 79% la practicaba de forma extracurricular. Presentar hábitos alimenticios no saludables genera mayor riesgo cardiovascular (OR: 5.57, IC 95% 1.95 – 15.90). El 67% (n= 67) tiene riesgo cardiovascular. Conclusiones: El género femenino, el grupo adolescente (15-18 años), el consumo de bebidas alcohólicas y hábitos alimenticios no saludables, se asocian con una mayor posibilidad de tener riesgo cardiovascular. Se encontró en un gran porcentaje de la población de estudio riesgo cardiovascular.Introduction: Cardiovascular diseases are among the leading causes of death worldwide and scientific evidence suggests that they have an origin at early ages, so that diminishing from adolescence the risks that contribute to its emergence is essential. Objective: To determine cardiovascular risk in the adolescent population of a high school of Timbío, Cauca, 2015 - 2016. Methodology: Quantitative, descriptive, observational and cross-sectional study. Sample: 100 students (47 women, 53 men), from 10 to 19 years old. Sociodemographic, anthropometric, physiological, biochemical variables (glycemia), personal history, family history, lifestyles and use of oral contraceptives were evaluated. Results: A higher prevalence of cardiovascular risk was found in the adolescent age group (15-18 years) with 84.6%; female gender was more likely to have cardiovascular risk (OR: 2.8, 95% CI 1.17 - 6.87); 7% said they use tobacco regularly and 12% are passive smokers. It was obtained that 26% ingested alcoholic beverages, with a higher prevalence between the ages of 15 to 18 years (OR: 19.4, 95% CI 2.45-48.11); In terms of physical activity, 79% practiced it extracurricularly. Presenting unhealthy eating habits generates greater cardiovascular risk (OR: 5.57, 95% CI 1.95 - 15.90). 67% (n = 67) have cardiovascular risk. Conclusions: The female gender, the adolescent group (15-18 years), drink alcoholic beverages and unhealthy eating habits, are associated with a greater possibility of having cardiovascular risk. It was found in a large percentage of the study population cardiovascular risk
Response to comment on 'Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity'
Lambert et al. question our retrospective and holistic epidemiological assessment of the role of chytridiomycosis in amphibian declines. Their alternative assessment is narrow and provides an incomplete evaluation of evidence. Adopting this approach limits understanding of infectious disease impacts and hampers conservation efforts. We reaffirm that our study provides unambiguous evidence that chytridiomycosis has affected at least 501 amphibian species
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