National Autonomous University of Nicaragua

About: National Autonomous University of Nicaragua is a education organization based out in Managua, Nicaragua. It is known for research contribution in the topics: Population & Public health. The organization has 775 authors who have published 715 publications receiving 9791 citations.

Hydrological and Geomorphological Controls on the Water Balance Components of a Mangrove Forest During the Dry Season in the Pacific Coast of Nicaragua

Abstract: Hydrological and geomorphological processes are key to mangrove forest growth and development However, few mangrove hydrology studies exist in Central America A 02 km2 mangrove forest on the Pacific coast of Nicaragua was investigated to determine the water balance dynamics during the dry season The used multi-methods approach combined hydrology, hydrochemistry and geophysics Precipitation is the main freshwater input Beach ridges are the key geomorphologic features which allowed an increase in water storage of 351 m3d−1 during a 22 day period Large precipitation events cause breaking of the beach ridges by excess water, suddenly emptying the system Grey water and pit latrines from the nearby town influence shallow groundwater quality, but also provide extra nutrients for the mangrove forest Groundwater chemistry is also affected by calcite dissolution and seawater Refreshening and salinization processes are controlled by the general groundwater flow direction Hydraulic and hydrochemical influence of seawater on coastal piezometers seems to be controlled by the elevation of the water table and the tidal amplitude These conditions control forest subsistence during the dry season, which is essential for the mangrove forest to provide ecological and economic benefits such as protection against flooding, habitat for numerous species, and tourist attraction

Monitoring of mercury and other metals mobility by sequential fractionation in soils nearby an abandoned chlor-alkali plant in Managua (Nicaragua)

Abstract: Lake Xolotlan (Nicaragua) is an important industrial area including heavy industries such as a fuel refinery and numerous industries that discharge their effluents to the lake. Mercury distribution was studied in soil samples from six different sites close to an old chlor-alkali plant (CAP) which has historically released mercury wastes to the lake and its surroundings. A Hg-specific sequential extraction procedure was used to assess Hg partitioning. Hg content was subdivided in operationally defined fractions named as labile mercury species, humic and fulvic complexes, elemental Hg and bound to crystalline oxides and bound to sulphide Hg and refractory species. The total mercury concentrations ranged between 1 and 123 mg kg−1. Sequential extractions revealed that both humic and fulvic complexes and elemental Hg constituted the major forms of mercury in the most samples. Both fractions are related with the accumulation of mercury from both atmospheric deposition and sewage outflow. Moreover, accumulation of the elemental Hg in these soils decreased with the increasing distance from the CAP. In addition, the study of the distribution of other elements revealed a remarkable availability of Al, Ba, Ca, Fe, Pb, Sr, V and Zn that are commonly related to petroleum treatment and combustion. This suggests that these soils are also affected by the releasing of other pollutants from a nearby refinery.

Structural Studies of the O-Antigenic Polysaccharides of Escherichia coli O3 and the Enteroaggregative Escherichia coli Strain 17-2

Abstract: The polysaccharide part of the lipopolysaccharide isolated from an enteroaggregative Escherichia coli isolated from a young child with diarrhoea in Santiago, Chile (strain 17-2), has been investigated. Sugar and methylation analyses of native and partially degraded polysaccharide together with 1H-NMR and 13C-NMR spectroscopies revealed that the polysaccharide is composed of pentasaccharide repeating units. The structure of the repeating unit of E. coli strain 17-2 O-polysaccharide is: The structure of the O-polysaccharide from E. coli O3 was shown to be identical to that of E. coli strain 17-2 by sugar and methylation analyses and by 1H-NMR and 13C-NMR spectroscopies.

Association of Genetic Polymorphisms in DC-SIGN, Toll-Like Receptor 3, and Tumor Necrosis Factor α Genes and the Lewis-Negative Phenotype With Chikungunya Infection and Disease in Nicaragua.

Abstract: Background Chikungunya infections range from subclinical infection to debilitating arthralgia and to chronic inflammatory rheumatism. Tumor necrosis factor (TNF) α, DC-SIGN (dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin), Toll-like receptor (TLR) 3, and blood groups have been directly or indirectly implicated in the susceptibility and pathogenesis of chikungunya. Methods To test the hypothesis that polymorphisms in genes coding for these molecules determine clinical outcomes of chikungunya infection, a retrospective case-control study was performed in Leon, Nicaragua. The study included 132 case patients and 132 controls, matched for age, sex and neighborhood. Case patients had clinical symptoms of chikungunya, which was diagnosed by means of polymerase chain reaction. Controls were individuals not reporting abrupt presentation of clinical chikungunya-like symptoms. Polymorphisms were identified by TaqMan single-nucleotide polymorphism genotyping assays. Results After adjustment for sociodemographic risk factors, chikungunya disease was associated with polymorphism in DC-SIGN and TLR3 genes (odds ratios, 5.2 and 3.3, respectively), and TNF-α with reduced persistent joint pain (0.24). Persistent joint pain was also associated with age, female sex and other comorbid conditions. Most interestingly, the Lewis-negative phenotype was strongly associated with both symptomatic chikungunya and immunoglobulin G seropositivity (odds ratios, 2.7, and 3.3, respectively). Conclusion This study identified polymorphisms in DC-SIGN, TLR3, and TNF-α genes as well as Lewis-negative phenotype as risk factors for chikungunya infection and disease progression.