43 research outputs found

    Un algoritmo esteganográfico vinculado a los cuadrados mágicos (Original)

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    The present work corresponds to the introduction of a new algorithm in the preparation of the students of the master's degree, Applied Mathematics of the University of Havana, corresponding to the Postgraduate course, "Steganography and Applications", in addition to the MININT members of In the province of Guantanamo, a novel steganographic algorithm linked to the spatial domain is presented, which uses a 128-bit private key together with the magic squares, with the purpose of hiding highly classified information, so that the resulting image after the insertion is not noticeable to any electronic monitoring system. The proposed algorithm improves in the level of imperceptibility analyzed through the PSNR values; In addition, it provides a quasi-perfect and safe system-stego system reflected in the values ​​achieved for relative entropy (Er). Put the summary in EnglishEl presente trabajo corresponde a la introducción de un novedoso algoritmo en la preparación de los estudiantes de la maestría, Matemática Aplicada de la Universidad de la Habana, correspondiente con el curso de Postgrado, “Esteganografía y Aplicaciones” , además a los  miembros de MININT de la provincia de Guantánamo, se presenta un novedoso algoritmo esteganográfico vinculado al dominio espacial, el cual utiliza una clave privada de 128 bits juntamente con los cuadrados mágicos, con el propósito de ocultar información altamente clasificada, de forma tal, que la imagen resultante tras la inserción no sea perceptible ante cualquier sistema electrónico de monitoreo. El algoritmo propuesto, mejora en cuanto al nivel de imperceptibilidad analizado a través de los valores de PSNR; además, el mismo brinda un estego-sistema cuasi-perfecto y seguro reflejado en los valores conseguidos para la entropía relativa (Er)

    Producción de hojarasca y retorno potencial de nutrientes en tres sitios del Estado de Nuevo León, México = Litterfall and potential nutrient return in three sites of the state of Nuevo León, México

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    RESUMEN Los objetivos de este estudio fueron estimar y cuantificar la dinámica mensual (enero a diciembre 2009) de la deposición de la hojarasca y macro (Ca, K, Mg, N y P) y microminerales (Cu, Fe, Mn, y Zn) de las hojas de la hojarasca en los municipios Los Ramones, China y Linares, del estado de Nuevo León, México. La vegetación está caracterizada como matorral espinoso tamaulipeco. La deposición anual total de hojarasca fue de 321.5 (Los Ramones), 431.6 (China) y 462.9 (Linares) g/m2/año. Las hojas representaron el mayor componente (154.4 a 304.5 g/m2/año) del total de hojarasca depositada. La deposición de ramas varió de 48.25 a 75.16 g/m2/año y la de estructuras reproductivas de 58.4 a 98.9 g/m2/año. La de otros componentes (material vegetal no identifi cado, cuerpos y heces de insecto) varió de 19.9 a 29.2 g/m2/año. La deposición anual de Caen los tres sitios fl uctuó de 3.4 a 8.1; K de 1.4 a 3.2; Mg de 0.76 a 1.6; N de 3.0 a 5.5 y P de 0.05 a 0.11 g/m2/año. El Cu fl uctuó de 0.84 a 2.8; Fe de 14.7 a 21.7; Mn de 5.5 a 11.8 y Zn de 3.3 a 5.2 mg/m2/año. En invierno se depositó la mayor cantidad de minerales. Además, en Linares se depositó la mayor cantidad de minerales y en Los Ramones la menor. Hubo diferencias espaciales y temporales en cantidad de hojarasca colectada y retorno de minerales, mas no así en la calidad foliar entre los sitios de estudio. ABSTRACT The aims of the study were to estimate and quantify the monthly dynamics (January to December 2009) of litterfall deposition and macro (Ca, K, Mg, N y P) and microminerals (Cu, Fe, Mn, y Zn) of litterfall leaves in the counties Los Ramones, China y Linares, of Nuevo León State, México. The plant community is named as Tamaulipan Thornscrub Annual deposition was 321.5 (Los Ramones), 431.6 (China) and 462.9 (Linares) g/m2/year. Leaves represented the highest component (154.4 to 304.5 g/m2/year) of total litterfall production. Branches varied from 48.25 to 75.16 g/m2/year. Reproductive structures from 58.4 to 98.9 g/m2/year and other components (unidentifi ed material, bodies and insect feces) ranked from 19.9 to 29.2 g/m2/year. Annual deposition of Ca in the three sites varied from 3.4 to 8.1; K from 1.4 to 3.2; Mg from 0.76 to 1.6; N from 3.0 to 5.5 and P from 0.05 to 0.11 g/m2/year. Cu ranked from 0.84 to 2.8; Fe from 14.7 to 21.7; Mn from 5.5 to 11.8 and Zn from 3.3 to 5.2 mg/m2/year. In winter mineral deposition was higher. Moreover, the highest mineral deposition occurred in Linares and Los Ramones was the lowest. There were spatiotemporal variations in quantity of literfall collected and return of minerals, but not so in leaf quality between study sites

    Litterfall production and nutrient deposition through leaf fallen in three tamaulipan thornscrub communities, north-eastern Mexico

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    Litterfall and the contents of macro- and micro-nutrients derived from its decomposition contribute greatly to the growth and productivity of forest ecosystem. The present study was undertaken to know the variability during two years in the deposition of litterfall and deposition of nutrients through leaf fallen litterfall in three sites of the state of Nuevo Leon (Los Ramones, China and Linares), north-eastern Mexico, which encompasses the Tamaulipan thornscrub plant community. The quantities of litterfall production and its constituents varied between 2009 and 2010, being the year 2010 where higher litterfall and nutrients occured. Mean litterfall production during the two years showed the following trend: Los Ramones (364.8), China (522.7) and Linares (583.1 g m-2 year-1). For leaf constituent, mean deposition ranged from 200.9 (Los Ramones) to 409.8 g m-2 year-1 (Linares), twigs from 62.4 (Los Ramones) to 89.3 (Linares), reproductive structures from 62.5 (Linares) to 80.3 (Los Ramones) and the miscellaneous component, constituted by unidentified plant material, body and insect feces, ranged from 21.1 (Linares) to 32.7 g m-2 year-1 (China). During the two years, mean annual deposition of Ca+K+Mg+P+N for Los Ramones, China and Linares was 10.1, 21.5 and 24.8 g m-2 year-1, respectively. Regardless of the research site, the order of macro and micro-nutrients deposition was as follows: Ca>N>K>Mg>P and Fe>Mn>Zn>Cu, respectively. There were spatial and temporal variations in litterfall deposition in terms of quantity, quality and potential nutrient returns. It is documented that the variability of litterfall and contents of nutrients derived from litterfall is influenced by the physioco-chemical characteristics of soils, diversity in vegetation and climatic conditions prevailing in different sites and year

    Scotiabank

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    El presente trabajo habla sobre la empresa Scotiabank en un enfoque hacia la gestión humana y de mejoras del mismo, para una empresa del tamaño de Scotiabank con millones de clientes y miles de empleados el área de RRHH es un área fundamental para mejorar y gestionar a los trabajadores y su productividad. En este trabajo se aborda información de la empresa enfocada en la gestión humana y propuestas de mejora basadas en sus políticas actuales

    Producción de hojarasca y retorno potencial de nutrientes en tres sitios del estado de Nuevo León, México

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    Los objetivos de este estudio fueron estimar y cuantificar la dinámica mensual (enero a diciembre 2009) de la deposición de la hojarasca y macro (Ca, K, Mg, N y P) y micro-minerales (Cu, Fe, Mn, y Zn) de las hojas de la hojarasca en los municipios Los Ramones, China y Linares, del estado de Nuevo León, México. La vegetación está caracterizada como matorral espinoso tamaulipeco. La deposición anual total de hojarasca fue de 321.5 (Los Ramones), 431.6 (China) y 462.9 (Linares) g/m2/año. Las hojas representaron el mayor componente (154.4 a 304.5 g/m2/año) del total de hojarasca depositada. La deposición de ramas varió de 48.25 a 75.16 g/m2/año y la de estructuras reproductivas de 58.4 a 98.9 g/m2/año. La de otros componentes (material vegetal no identifi cado, cuerpos y heces de insecto) varió de 19.9 a 29.2 g/m2/año. La deposición anual de Ca en los tres sitios fluctuó de 3.4 a 8.1; K de 1.4 a 3.2; Mg de 0.76 a 1.6; N de 3.0 a 5.5 y P de 0.05 a 0.11 g/m2/año. El Cu fluctuó de 0.84 a 2.8; Fe de 14.7 a 21.7; Mn de 5.5 a 11.8 y Zn de 3.3 a 5.2 mg/m2/año. En invierno se depositó la mayor cantidad de minerales. Además, en Linares se depositó la mayor cantidad de minerales y en Los Ramones la menor. Hubo diferencias espaciales y temporales en cantidad de hojarasca colectada y retorno de minerales, mas no así en la calidad foliar entre los sitios de estudio

    FPGA-Based Smart Sensor for Online Displacement Measurements Using a Heterodyne Interferometer

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    The measurement of small displacements on the nanometric scale demands metrological systems of high accuracy and precision. In this context, interferometer-based displacement measurements have become the main tools used for traceable dimensional metrology. The different industrial applications in which small displacement measurements are employed requires the use of online measurements, high speed processes, open architecture control systems, as well as good adaptability to specific process conditions. The main contribution of this work is the development of a smart sensor for large displacement measurement based on phase measurement which achieves high accuracy and resolution, designed to be used with a commercial heterodyne interferometer. The system is based on a low-cost Field Programmable Gate Array (FPGA) allowing the integration of several functions in a single portable device. This system is optimal for high speed applications where online measurement is needed and the reconfigurability feature allows the addition of different modules for error compensation, as might be required by a specific application

    Prognostic factors of Infective Endocarditis in Patients on Hemodialysis: A Case Series from a National Multicenter Registry.

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    Background: Infective endocarditis (IE) is a severe complication associated with high mortality. Objectives: To examine the clinical characteristics of IE in hemodialysis (HD) patients and to determine prognostic factors related to HD. Methods: From January 2008 to April 2015, 2,488 consecutive patients with definite IE were included. Clinical characteristics of IE patients on HD were compared with those of IE patients who were not on HD. Results: A total of 126 patients (63% male, median age: 66 years; IQR: 54-74 years) with IE (5.1%) were on HD. Fifty-two patients died during hospitalization (41%) and 17 additional patients (14%) died during the first year. The rate of patients who underwent surgery during hospitalization was lower in HD patients (38 patients, 30%) than in non-HD patients (1,177 patients, 50%; p 70 years (OR: 4.1, 95% CI: 1.7-10), heart failure (OR: 3.3, 95% CI: 1.4-7-6), central nervous system (CNS) vascular events (OR: 6.7, 95% CI: 2.1-22) and septic shock (OR: 4.1, 95% CI: 1.4-12.1) were independently associated with fatal outcome in HD patients. Of the 38 patients who underwent surgery, 15 (39.5%) died during hospitalization. Conclusions. HD patients with IE present a high mortality. Advanced age and complications, such as heart failure, CNS stroke or septic shock, are associated with mortality.pre-print714 K

    The Recognition of N-Glycans by the Lectin ArtinM Mediates Cell Death of a Human Myeloid Leukemia Cell Line

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    ArtinM, a d-mannose-binding lectin from Artocarpus heterophyllus (jackfruit), interacts with N-glycosylated receptors on the surface of several cells of hematopoietic origin, triggering cell migration, degranulation, and cytokine release. Because malignant transformation is often associated with altered expression of cell surface glycans, we evaluated the interaction of ArtinM with human myelocytic leukemia cells and investigated cellular responses to lectin binding. The intensity of ArtinM binding varied across 3 leukemia cell lines: NB4>K562>U937. The binding, which was directly related to cell growth suppression, was inhibited in the presence of Manα1-3(Manα1-6)Manβ1, and was reverted in underglycosylated NB4 cells. ArtinM interaction with NB4 cells induced cell death (IC50 = 10 µg/mL), as indicated by cell surface exposure of phosphatidylserine and disruption of mitochondrial membrane potential unassociated with caspase activation or DNA fragmentation. Moreover, ArtinM treatment of NB4 cells strongly induced reactive oxygen species generation and autophagy, as indicated by the detection of acidic vesicular organelles in the treated cells. NB4 cell death was attributed to ArtinM recognition of the trimannosyl core of N-glycans containing a ß1,6-GlcNAc branch linked to α1,6-mannose. This modification correlated with higher levels of N-acetylglucosaminyltransferase V transcripts in NB4 cells than in K562 or U937 cells. Our results provide new insights into the potential of N-glycans containing a β1,6-GlcNAc branch linked to α1,6-mannose as a novel target for anti-leukemia treatment

    Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

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    Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection
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