Examinando 3.2 Pasantías y ponencias por Título

Publicación

A Comparative Study on Activated Carbons Derived from a Broad Range of Agro-industrial Wastes in Removal of Large-Molecular-Size Organic Pollutants in Aqueous Phase

(Springer Nature, 2015)

Cruz, GJF

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Matejova, L

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Pirila, M

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Ainassaari, K

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Canepa, CA

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Solis, J

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Cruz, JF

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Solcova, O

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Keiski, RL

Microporous–mesoporous activated carbons from five different types of agro-industrial wastes were produced using chemical activation with ZnCl2 and carbonization at mild conditions of 600 °C, comprehensively characterized and investigated for removal of methylene blue (MB) in aqueous solution, a model large-molecular-size organic pollutant. The external part of the mango pit (mango seed husk) was used for the production of activated carbon (AC) for the first time. Despite that the raw agro-materials exhibited significantly different porosity, all activated carbons produced possessed well-developed microporous–mesoporous structures showing high surface areas and micropore volumes.

Publicación

A comparative study on the phenolic bioaccessibility, antioxidant and inhibitory effects on carbohydrate-digesting enzymes of maca and mashua powders

(Academic Press, 2020)

Paucar-Menacho L.M.

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Peñas E.

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Hernandez-Ledesma B.

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Frias J.

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Martínez-Villaluenga C.

The polyphenolic content of dehydrated maca (MA) and mashua (M) powders, promising functional ingredients, and their antioxidant activity and inhibition of carbohydrate digestion was evaluated following in vitro gastrointestinal digestion (GID). Moreover, the impact of steaming on bioaccessibility and bioactivity of the M phenolic fraction was investigated. MA phenolic fraction composed mainly of caffeic-4-O-glucosides showed high bioaccessibility (117.8%), antioxidant activity (142.9 μmol Trolox equivalents, TE/g) and weak effectiveness to inhibit carbohydrate digestion after GID. Anthocyanins were the major compounds in the M phenolic fraction with low bioaccessibility (22.4%), although a superior antioxidant activity (446.7 μmol TE/g) and modest inhibitory effects on carbohydrate digestion after GID. Generally, bioaccessibility and bioactivity of M decreased after steaming process. MA and M powders contain appreciable concentrations of phenolics, although M polyphenols were more effective on modulating carbohydrate digestion. © 2020 Elsevier Ltd

Publicación

A Comparison of Digital Modelling Techniques Analyzing a Section of Qhapaq Nan

(IEEE Xplore, 2015)

Retamozo, S

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Arce, D

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Aguilar, R

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Zvietcovich, F

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Quintana, M

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Castaneda, B

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Angeles, S

Total Station has been one of the most common acquisition devices for achieving maps through topographic survey. Nowadays, Terrestrial Laser Scanner (TLS) and Photogrammetry are commonly used to generate accurate meshes. In addition, commercial products such as Kinect offer low cost technology to acquire point-cloud information. The present paper aims to measure the accuracy of these digital modelling techniques by employing elevation contour maps, surface deviations and distance measurements. For this purpose, a 450 m sector of the Qhapaq Nan located in Lima-Peru, was selected as a case of study. A camera-enabled drone was used for acquiring pictures to obtain a high-resolution photogrammetric model. Subsequently, a 3D survey of the monument was conducted with a time-of-flight laser scanner. Contour elevation lines where extracted from TLS, Photogrammetry and Total Station models at the same depths in order to determine the precision of photogrammetry and laser scanner reconstructions. In addition, geometrical comparisons were performed among the 3D models above mentioned and the Kinect sensor. The comparison showed that TLS is the most accurate tool for 3D reconstruction. However, Photogrammetry and Kinect provided errors of less than one centimeter in accuracy.

Publicación

A computer algorithm for detection of tuberculosis bacilli in Ziehl Nellsen sputum smear images based on the adjustment of RGB primary component tones and geometric eccentricity

(International Institute of Informatics and Systemics, IIIS, 2017)

Del Carpio C.

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Dianderas E.

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Zimick M.

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Sheen P.

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Coronel J.

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Fuentes P.

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Kemper G.

The present study proposes a method of automatic detection of tuberculosis (TB) bacilli from digital images of Ziehl Neelsen sputum smear baciloscopy. The method is based on an algorithm that aims to automate the interpretation of optical microscopic images of sputum smears. According to the World Health Organization (WHO), a specialist can not analyze and process more than 20 samples per day (in order to not affect the analysis sensitivity and commit errors in diagnosis). Therefore, an automated tool as the proposed here, is an important contribution to the current efforts to fight tuberculosis. The algorithm is based on geometric eccentricity of ellipses and improvement of RGB component tones. Correspondence functions adjusted to sample preparation conditions were applied in order to improve the RGB primary component tones of the image. This allows to obtain an adequate segmentation of interest objects. For the recognition of each object as bacillus, the geometric descriptor of eccentricity of the ellipse was applied. The algorithm was validated with 66 independent sputum samples from TB patients. A sensitivity of 88.75% and a specificity of 95.5% was obtained for the diluted pellet method for sample preparation. © by the International Institute of Informatics and Systemics.

Publicación

A mixed methodology for detailed 3D modeling of architectural heritage

(Tayler & Francis Group, 2016)

Arce, D

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Retamozo, S

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Aguilar, R

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Castaneda, B

Architectural and archaeological heritage is the most representative part of history of a country. For these reasons, over the years, the scientific community has focused its attention on three-dimensional (3D) modeling techniques, conservation, structural analysis and other related applications. Laser scanning, shape from structured light, shape from silhouette, shape from video and shape from photometry are among the techniques that have been used over the past years for 3D modeling of archeological heritage. The application of 3D modeling can be found in several disciplines. In Architecture, it is used to generate digital models from which drawings can be produced. Aerial and terrestrial photogrammetry Photogrammetry is commonly used for digitization of 3D models in different applications due to the fast acquisition process and low cost of equipment. Digitization of structures with terrestrial laser scanner requires the usage of a correct methodology in order to generate a complete 3D model.

Publicación

A new Clathria (Demospongiae, Microcionidae) from Peru occurring on rocky substrates as well as epibiontic on Eucidaris thouarsii sea urchins

(Magnolia Press, 2011)

Aguirre, LK

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Hooker, Y

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Willenz, P

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Hajdu, E

Southeastern Pacific sponges (Phylum Porifera) range among the world’s least known faunas, with only 13 species reported to date from the entire Peruvian coast. This state of affairs motivated the onset of two large, cooperative, exploratory initiatives, with the aim of mapping sponge richness and distribution in the area: Proyectos ESPER and EsponjAS. Over 800 specimens have been collected in Peru since 2007, with identifications still in progress. Among these, a sponge species originally thought to be an exclusive epibiont on Eucidaris thouarsii sea urchins, relatively conspicuous on Peru’s Punta Sal region. This sponge, latter found to occur on additional substrates too, is described as a new species of Clathria (Microciona). Cidarid density ranged between 1.5 and 12/m2 , and largest diameter of the tests between 3.2 and 5.6 cm. Total number of spines on each sea urchin varied between 68 and 96, and percent sponge coverage of these, between 18.2 and 75.7. There appears to be only a slight tendency for increased sponge coverage on larger sea urchins, so there may be factors, other than sea urchin age, shaping this association. Clathria (Microciona) aculeofila sp. nov. can be markedly dominant as an epibiont on E. thouarsii, albeit the great sponge richness in the area. This is in contrast to the allegedly opportunistic, diverse epibiosis by sponges reported previously for Antarctic cidaroids

Publicación

A new species of Bryophryne (Anura: Strabomantidae) from the Cordillera de Vilcabamba, southeastern Peruvian Andes

(Universidade de Sao Paulo, Agencia USP de Gestao da Informacao Academica (AGUIA), 2017)

Mamani, Luis

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Catenazzi, Alessandro

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Ttito, Alex

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Mallqui, Sergio

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Chaparro, Juan C.

A new species of Bryophryne (Anura: Strabomantidae) from the Cordillera de Vilcabamba, southeastern Peruvian Andes. We describe a new species of Bryophryne from the Cordillera de Vilcabamba in Department Cusco, in the southeastern Peruvian Andes. The new species differs from all other congeneric taxa, except B. flammiventris and B. gymnotis, by possessing a weakly defined tympanic membrane and tympanic annulus, by the presence of vocal sac and vocal slits in males, and by producing advertisement calls. The new species is distinguished from B. flammiventris and B. gynznotis by skin texture, presence of small, oblique dentigerous processes on the vomer, ventral coloration ranging from bluish-gray to whitish-gray with irregular or reticulate dark brown spots, and call composed of two or three notes. The new species is further characterized by having dorsal skin shagreen with tubercles, discontinuous dorsolateral folds, skin smooth on ventral surfaces of the body, and lateral fringes on fingers and toes. This species was found at the transition from montane forest to high Andean pupa, where it occurs in moist microhabitats under moss and rocks at elevations from 3519 to 3707 m a.s.l.

Publicación

Antioxidant properties of mashua (Tropaeolum tuberosum) phenolic extracts against oxidative damage using biological in vitro assays

(Elsevier Ltd, 2008)

Chirinos R.

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Campos D.

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Warnier M.

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Pedreschi R.

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Rees J.-F.

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Larondelle Y.

Purified mashua extracts (PME) from four different coloured mashua genotypes were assayed for oxidative damage prevention. Three in vitro assays for oxidative damage to biological structures rich in polyunsaturated fatty acids (PUFA), such as LDL and erythrocytes, were tested: AAPH-induced TBARS assay and Cu2+-induced conjugated dienes assay for LDL oxidation and AAPH-induced oxidative hemolysis of erythrocytes. Additionally, ORAC antioxidant capacity, total phenolics (TP), total flavanoids (TFA) and total anthocyanins (TA) were evaluated. In the presence of 5 lM of gallic acid equivalents (GAE), inhibitions of LDL oxidation for the PME ranged from 29.1% to 34.8% and from 51.8% to 58.1% when the TBARS and conjugated dienes assays were performed, respectively. PME inhibited the hemolysis of erythrocytes within the range 20.8–25.1%. Thus, mashua phenolic extracts are capable of scavenging peroxyl radicals, as well as chelating redox metal ions in vitro. ORAC and LDL protection (TBARS and conjugated dienes assays) showed good correlations with the TP and TFA, suggesting that these compounds have a good ability to protect LDL molecules under the employed conditions. In contrast, inhibition of hemolysis did not show any correlation with the evaluated phenolic assays (TP, TA, TFA) or with any of the evaluated oxidative LDL assays, suggesting a specific action of some non-evaluated compounds present in the PME. The results of this study indicate that the mashua polyphenol extracts displayed good antioxidant properties against oxidative damage in biological structures rich in PUFA. The displayed antioxidant properties could be applied in the field of food or cosmetic industry.

Publicación

Arsenic in Peruvian rice cultivated in the major rice growing region of Tumbes river basin

(Elsevier Ltd, 2020)

Mondal D.

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Periche R.

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Tineo B.

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Bermejo L.A.

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Rahman M.M.

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Siddique A.B.

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Rahman M.A.

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Solis J.L.

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Cruz G.J.F.

Arsenic (As) exposure from surface and groundwater in Peru is being recognised as a potential threat but there are limited studies on As in the food-chain and none on As in Peruvian rice. In this study, we have determined the As content in rice cultivated in the Tumbes river basin located in the northern province of Peru, an area known for extensive rice cultivation. We collected rice and soil samples from agricultural fields, soil was collected using grid sampling technique while rice was collected from the heaps of harvested crop placed across the fields. The average total As concentration in rice was 167.94 ± 71 μg kg−1 (n = 29; range 68.39–345.31 μg kg−1). While the rice As levels were not highly elevated, the As content of few samples (n = 7) greater than 200 μg kg−1 could contribute negatively to human health upon chronic exposure. Average concentration of As in soil was 8.63 ± 7.8 mg kg−1 (n = 30) and soil to grain transfer factor was 0.025 ± 0.018 for 12 matched samples. Compared to our previous pilot study in 2006 (samples collected from the same agricultural fields but not from exact locations) there was a 41% decrease in As soil concentration in this study. Rice samples collected in 2006 (n = 5) had a mean concentration of 420 ± 109 μg kg−1. Our data provides a baseline of rice grain As concentrations in Peruvian province of Tumbes and warrants further studies on factors affecting uptake of As by the rice varieties cultivated in Peru and any potential human health risks. © 2019 Elsevier Ltd

Publicación

Biomechanical study of proximal femur for designing stems for total hip replacement

(MDPI AG, 2020)

Solórzano W.

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Ojeda C.

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Lantada A.D.

Innovative hip implants should be designed in accordance with biomechanical models of the proximal femur and take into account both body weight and muscle action in order to improve usability and biomimetic performance. This article proposes a finite element analysis of the proximal femur using both cortical and trabecular regions and employing transverse isotropic properties with standardized loads taken from active and young patients. Maximum principal stresses are plotted to show the mechanical behavior of the femur and grouped to evaluate stress shielding. Tsai-Wu and the maximum principal stress fields are useful for finding the areas more prone to failure and analyzing the influence of the stems on femoral mechanics. Other parameters, such as the stem material, absence of neck and osteotomy level, are explained. This paper is expected to provide a guide for designers and surgeons of femoral stems for assessing qualitatively and quantitatively the risks of stress shielding. © 2020 by the authors.

Publicación

Bioprospection of native psychrotolerant plant-growth-promoting rhizobacteria from peruvian andean plateau soils associated with chenopodium quinoa

(Canadian Science Publishing, 2020)

Chumpitaz-Segovia C.

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Alvarado D.

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Ogata-Gutiérrez K.

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Zúñiga-Dávila D.

The Peruvian Andean Plateau, one of the main production areas of native varieties of Chenopodium quinoa, is exposed to abrupt decreases in environmental temperature, affecting crop production. Plant-growth-promoting rhizobacteria that tolerate low temperatures could be used as organic biofertilizers in this region. We aimed to bioprospect the native psychrotolerant bacteria of the quinoa rhizosphere in this region that show plant-growth-promoting traits. Fifty-one strains belonging to the quinoa rhizosphere were characterised; 73% of the total could grow at low temperatures (4, 6, and 15 °C), whose genetic diversity based on DNA amplification of interspersed repetitive elements (BOX) showed 12 different profiles. According to the 16S rRNA sequence, bacterial species belonging to the classes Beta-and Gammaproteobacteria were identified. Only three (6%) isolates identified as nonpathogenic bacteria exhibited plant-growth-promoting activities, like IAA production, phosphate solubilization, growth in a nitrogen-free medium, and ACC deaminase production at 6 and 15 °C. ILQ215 (Pseudomonas silesiensis) and JUQ307 (Pseudomonas plecoglossicida) strains showed significantly positive plant growth effects in aerial length (about 50%), radicular length (112% and 79%, respectively), and aerial and radicular mass (above 170% and 210%, respectively) of quinoa plants compared with the control without bacteria. These results indicate the potential of both psychrotolerant strains to be used as potential organic biofertilizers for quinoa in this region. © 2020, Canadian Science Publishing. All rights reserved.

Publicación

Caracterización morfológica y molecular de las especies del género Croton L. (Euphorbiaceae) denominadas “sangre de grado” en la Amazonía peruana

(Universidad Nacional Mayor de San Marcos, 2019)

Ore Rengifo, Malu Isaura

El género Croton es un género gigante que alberga a más de 1200 especies. Dentro de estas, alrededor de 25 especies son denominadas en Perú “sangre de grado” y pertenecen a los subgéneros Adenophylli (seccs. Cyclostigma y Adenophylli), Geiseleria (secc. Luntia) y Quadrilobi (secc. Sampatik). La importancia de estos árboles radica principalmente en el uso medicinal del látex (exudado al cortar la corteza) por sus capacidades cicatrizantes. Sin embargo, debido a que la mayoría de especies de “sangre de grado” son cercanas taxonómicamente y fácilmente confundibles, estas son comercializadas bajo el único nombre científico de Croton lechleri, sin una identificación validada, resultando en productos probablemente no fiables en su composición (i.e., qué especie o especies son realmente usadas), con los riesgos que esto acarrea.

Publicación

Carboxymethyl kappa/iota-hybrid carrageenan doped with NH4I as a template for solid bio-electrolytes development

(Elsevier B.V., 2019)

Torres, FG

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Arroyo, J

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Alvarez, R

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Rodriguez, S

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Troncoso, O

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Lopez, D

In this study, we analyzed the contribution of NH4I and glycerol on the ionic conductivity of carboxymethyl κ/ι-hybrid carrageenan-based solid bio-electrolytes. Electrochemical impedance spectroscopy was used to assess the electrochemical properties of the developed biopolymeric films and their interfaces over a wide range of frequencies (1& Hz–7& MHz). X-ray diffractograms demonstrated the increment of the amorphous fraction in the material as the NH4I content increases, suggesting an enhancement of ion transport processes and the successful incorporation of the salt into the host matrix. The shift of the OH peaks in the FTIR spectra confirmed the interaction between carboxymethyl carrageenan, NH4I, and glycerol. EIS results were represented in the complex plane and were fitted to an Rs(R1Q1) equivalent circuit. The ionic conductivity for carboxymethyl carrageenan doped with xNH4I (x = 15& wt%, 25& wt%, 35& wt%) and glycerol (15& wt%, 25& wt%) increased at higher salt and plasticizer content. This behavior was explained in terms of salt association/dissociation processes. The maximum ionic conductivity found in this study was 3.9& ×& 10−3& S/cm at room temperature. This result suggests that modified carrageenan-based materials can be suitable for the development of solid bio-electrolytes for electrochemical and energy storage applications. © 2018 Elsevier B.V.

Publicación

Carboxymethyl κ/ι-hybrid carrageenan doped with NH4I as a template for solid bio-electrolytes development

(Elsevier Ltd, 2019)

Torres F.G.

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Arroyo J.

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Alvarez R.

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Rodriguez S.

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Troncoso O.

;

López D.

In this study, we analyzed the contribution of NH4I and glycerol on the ionic conductivity of carboxymethyl κ/ι-hybrid carrageenan-based solid bio-electrolytes. Electrochemical impedance spectroscopy was used to assess the electrochemical properties of the developed biopolymeric films and their interfaces over a wide range of frequencies (1& Hz–7& MHz). X-ray diffractograms demonstrated the increment of the amorphous fraction in the material as the NH4I content increases, suggesting an enhancement of ion transport processes and the successful incorporation of the salt into the host matrix.

Publicación

Characterization of healthy skin with high-frequency ultrasound using quantitative ultrasound

(Pontificia Universidad Católica del Perú, 2018)

Saavedra Bazán, Ana Cecilia

The skin is the largest organ of the body that protects it from the external environment. High- frequency ultra sound (HF-US) has been used to visualize the skin in depth and to diagnose some pathologies in dermatological applications. Quantitative ultrasound (QUS) includes several techniques that provide values of particular physical properties. In this thesis work, three QUS parameters are explained and used to characterize healthy skin through HF-US: attenuation coefficient slope (ACS), backscatter coefficient (BSC) and shear wave speed (SWS). They were estimated with the regularized spectral-log difference (RSLD) method, the reference phan- tom method, and the crawling wave sonoelastography method, respectively. All the three parameters were assessed in phantoms, ex vivo and in vivo skin. In calibrated phantoms, RSLD showed a reduc- tion of up to 93% of the standard deviation concerning the estimation with SLD, and BSC showed an agreement with the Faran’s theoretical curve. In gelatin-based phantoms, surface acoustic waves (SAWs) were estimated in two interfaces: solid-water and solid-US gel, which all owed corroborating SAWs presence and finding an empirical compensation factor when the coupling interface is US gel. A correction factor of 0:97 for SAW-to-shear was found to avoid underestimation in phantoms. Porcine thigh was calculated in the range from 8 to 27 MHz, where the ACS was 4:08 _+_0:43 dB cm -1 MHz-1 and BSC was in the range from 10 1 to 10° sr-1 _cm-1. Crawling wave sonoelastography method was applied for the vibration frequencies between 200 Hz and 800 Hz, where SWS was in the range from 4:6 m/sto9:1 m/s. In vivo ACS and BSC were assessed in the healthy forearm and thigh, whereas SWS only in the thigh. The average ACS in the forearm dermis was 2.07dB cm-1 _MHz-1, which is in close agreement with the literature. A significant difference (p < 0.05) was found between the ACS in the forearm dermis and the thigh dermis (average ACS of 2.54dB cm-1 _MHz-1). The BSC of the forearm and thigh dermis were in the range from 10 -1 to 10° sr-1 _cm-1, and in the range from 10-1 to 10° sr-1 _cm-1, respectively. The SWS in the thigh dermis was 2:4 _+_0:38 m/s for a vibration frequency of 200Hz, with an increasing trend as frequency increases. Results suggest that these QUS parameters have the potential to be used as a tool for in vivo skin characterization and show potential for future application in skin lesions.

Publicación

Chronic hypoxia induces modification of the N-methyl-D-aspartate receptor in rat brain

(Elsevier, 1996)

Pichiule P.

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Chávez J.C.

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Boero J.

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Arregui A.

This study examined [3H]MK-801 binding to the N-methyl-D-aspartate (NMDA) receptor in membranes prepared from cerebral cortex, hippocampus and corpus striatum of 3 week old rats exposed to 10 weeks of intermittent hypobaric hypoxia (4300 m; 450 Torr) and compared results wiLh those of normoxic controls. The cortex, hippocampus and striatum of hypoxic animals had a 36, 35 and 31% reduction in binding sites (Bmax) and a 29, 32 and 17% decrease (reflecting increased affinity) in the dissociation constant (Kd) when compared to controls. In the cerebral cortex, both glutamate (100 #M) and glycine (10 #M) enhanced [3H]MK-801 binding by two to 3- fold: Coagonist glutamate, however, had a higher ECs0 (0.44 #M) in the hypoxic cortical membranes when compared to controls (0.28 #M). No significant differences were found in the ECs0 of glycine. The results show that the NMDA receptor is altered in several brain regions of rats developing in a hypoxic environment.

Publicación

Cognitive impairment and hypertension in older adults living in extreme poverty: A cross-sectional study in Peru

(BioMed Central Ltd., 2017)

Lazo-Porras M.

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Ortiz-Soriano V.

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Moscoso-Porras M.

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Runzer-Colmenares F.M.

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Málaga G.

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Jaime Miranda J.

Previous studies have shown that hypertension is a risk factor for cognitive impairment, but whether this association is also present in extremely poor populations in Low Middle Income Countries settings remains to be studied. Understanding other drivers of cognitive impairment in this unique population also merits attention. Methods: We performed a secondary analysis using data from the "Encuesta de Salud y Bienestar del Adulto Mayor", a regional survey conducted in an extremely poor population of people older than 65 years old from 12 Peruvian cities in 2012. The outcome variable was cognitive impairment, determined by a score of ≤7 in the modified Mini-Mental State Examination. The exposure was self-reported hypertension status. Variables such as age, gender, controlled hypertension, education level, occupation, depression and area of living (rural/urban) were included in the adjusted analysis. We used Poisson regression with robust variance to calculate prevalence ratios (PR) and 95% confidence interval (95% CI) adjusting for confounders. Results: Data from 3842 participants was analyzed, 51.8% were older than 70 years, and 45.6% were females. The prevalence of cognitive impairment was 1.7% (95% CI 1.3%-2.1%). There was no significant difference on the prevalence of cognitive impairment between the group of individuals with hypertension in comparison with those without hypertension (PR = 0.64, 95% CI 0.33-1.23). Conclusions: The association described between hypertension and cognitive impairment was not found in a sample of extremely poor Peruvian older adults. © 2017 The Author(s).

Publicación

Compact Invariant Sets for Global Holomorhic Foliations

(Springer Nature, 2017)

Fernandez-Perez, A

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Mol, R

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Rosas, R

We study compact invariant sets for holomorphic foliations on Stein manifold. As application, we show some dynamical properties concerning minimal sets (with singularities) of foliations and real analytic Levi-flat hypersurfaces in projective spaces.

Publicación

Computer Aided Medical Diagnosis Tool to Detect Normal/Abnormal Studies in Digital MR Brain Images

(IEEE Xplore, 2014)

Gutierrez-Caceres, J

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Portugal-Zambrano, C

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Beltran-Castanon, C

This work presents a model to support medical diagnosis through the classification of abnormality normality in medical brain images, in order to help to specialist as a previous step in the brain pathology diagnosis. Our proposal was incorporated into a content-based image retrieval system, thus we developed a useful tool for radiologists. The first step produces the features vector of MR image using Gabor Filter for the data train and test, then as second step features vector of training data are indexed into CBIR module. The third step makes the training of SVM and as four step the test dataset is classified with the SVM trained. Finally, the result of classification are presented with a set of similar images product of a KNN query. This model was implemented as a software tool with graphical interface. We obtained 94.12% of correct classification. Our medical image dataset is composed of 187 MRI images collected from a medical diagnosis company and selected by medical specialist. The result shows that the proposed model is robust and effective as a software tool to aid support to medical diagnostic.

Publicación

Construcción de superficies equipotenciales gravitatorias para satélites sel sistema global de navegación por satélite (GNSS)

(Universidad Nacional de Ingeniería, 2016)

Chévez Abanto, Leonardo José

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Chévez Abanto, Leonardo José

Con el creciente número de aplicaciones del geoposicionamiento, se pone cada vez mayor énfasis en el mejor cálculo de trayectorias de satélites que luego serán usados como referencia para el cálculo de la posición de un vehículo receptor en Tierra. Las trayectorias de los satélites son determinadas por el campo gravitatorio causado principalmente por la Tierra, el Sol, la Luna, Júpiter y otros cuerpos celestes; sin embargo, conocer el campo gravitatorio total no es tan simple. Con la finalidad de hallar el campo gravitatorio circundante a la Tierra existen misiones encargadas de medir el gradiente gravitatorio a 280 km de altura, tales como la misión GOCE (Gravity field and steady-state Ocean Circulation Explorer). En este trabajo se usan las mediciones de la misión GOCE para determinar el potencial gravitatorio total alrededor de la Tierra en forma “analítica”, que será usado para construir superficies equipotenciales gravitatorias y un mejor y más preciso cálculo de las trayectorias de satélites GNSS (Global Navigation Satellite System) que orbitan la Tierra. Palabras clave: satélites, misión GOCE, potencial gravitatorio. With the increasing number of applications of GEO, it puts the emphasis on the best estimate of trajectories of satellites increases to which will then be used as a reference for calculating the position of a receiver vehicle on Earth. The trajectories of satellites are determined by the gravitational field produced principally by the Earth, the Sun, the Moon and others celestial bodies, but to know the total gravitational field is not so simple. In order to find the gravitational field surrounding Earth missions are responsible for measuring gravity gradient at height 280 km such as GOCE mission (Gravity field and steady-state Ocean Circulation Explorer). In this work the mission GOCE measurements are used to determine "analytically" the total gravitational potential around the Earth that can be used for build gravitational equipotential surfaces and a better and more accurate calculation of the trajectories of satellites orbiting the Earth. Keywords: satellites, GOCE mission, gravitational potential.

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