Papers by miguel saavedra
Revista de Investigación de Física, 2011
En el presente trabajo se realiza un estudio basado en los datos de Reanálisis para identificar l... more En el presente trabajo se realiza un estudio basado en los datos de Reanálisis para identificar los principales patrones de circulación atmosférica en sudamérica. Para el procesamiento de la información no se realiza ninguna distinción entre años El Niño y no El Niño, considerando solo promedios de los principales variables meteorológicas, para la identificación de patrones de la circulación atmosférica. Mediante el análisis de las gráficas de presión atmosférica y vientos, se identifica que la circulación superficial esta gobernada principalmente por la presencia de los anticiclones del Pacífico y Atlántico sur respectivamente, y a niveles altos el sistema denominado Alta de Bolivia, cuya influencia se observa a partir de 500 hPa. Por su parte, los patrones para la precipitación se destacan la Zona de Convergencia Intertropical, ZCIT, la Zona de Convergencia del Atlántico Sur, ZCAS, y los desiertos costeros que se ubican a lo largo de las costas de Perú y Chile. La ZCIT oscila cerc...
ABSTRACT: The aim of this work is to analyze the differences between players of a group following... more ABSTRACT: The aim of this work is to analyze the differences between players of a group following a token economy program and another who does not follow it. The results indicate that young players perceive that their trainers have a preference for attacking actions during the match; this unanimity in preferences disappears during training. Significant differences were found significant differences in the preferences of coach during training; which means that belonging to one group of study implies different choices. There have been found significant differences between groups in specific skills related to defense and ball reception.
Revista de Investigación de Física, 2012
Un terremoto remeció la región centro-sur del Perú, el 15 de agosto del 2007. Como efecto cosísmi... more Un terremoto remeció la región centro-sur del Perú, el 15 de agosto del 2007. Como efecto cosísmico se produjo un maremoto que inundó algunos poblados y balnearios costeros. Del análisis y el procesamiento de nueve señales mareográficas observadas se puede obtener los parámetros que caracterizan la deformación cosísmica inicial mediante un proceso de inversión, en el cual se compara la señal calculada con la señal observada a través de un proceso de mínimos cuadrados no-negativos. El valor máximo del deslizamiento es de 7.0 m ubicado en la parte sur de la geometría de ruptura. El momento sísmico escalar calculado es M0 = 1.99 × 10<21> Nm, lo que equivale a una magnitud de 8.1 Mw. Como resultado se obtiene un modelo heterogéneo de la fuente sísmica que es la condición inicial para simular la propagación e inundación del maremoto.
Data in Brief, 2021
The first weather radar campaign over Lima, the capital of Peru, a desertic area on the western s... more The first weather radar campaign over Lima, the capital of Peru, a desertic area on the western side of the Peruvian Andes, was carried out to study the occurrence of rain events in summer 2018. The weather radar was installed strategically and was able to overlook three river basins: Rimac, Chillón, and Lurin. An X-band radar (PX-10 0 0) was used, which operates at 9.55 GHz. PX-10 0 0 was built by the Advanced Radar Research Center (ARRC) at the University of Oklahoma (U.S.A.). The radar operated from January 26th to April 1st, 2018, at Cerro Suche located 2910 m ASL and 55 km from the city of Lima. The PX-10 0 0 performed plan-positionindicators (PPI) for elevations starting at 0 °up to 20 °. The data presented here were obtained using a three-dimensional constant-altitude plan-position-indicator (3D CAPPI), which was generated by high resolution (250 m) nearest point algorithm.
Acta Tropica, 2020
Mendoza province, in central west Argentina, is considered among the high-risk provinces for vect... more Mendoza province, in central west Argentina, is considered among the high-risk provinces for vector transmission of Trypanosoma cruzi, the causative agent of Chagas disease. Extensive goat farming is common in large parts of rural Mendoza, and goats may act as a reservoir for this parasite. The objective of this study was to determine infection rates, parasite loads, and seasonal variation of these parameters in T. cruzi infection in goats from rural areas of three departments of Mendoza. A total of 349 peripheral blood samples with EDTA / guanidine were analyzed from goats on 11 farms (three in Lavalle, three in San Carlos, and five in Malargüe department) in spring of 2014, 2015, and 2016; and in fall of 2015 and 2016 (only Malargüe). DNA was extracted using a Phenol: Chloroform: Isoamyl protocol. The detection and quantification of T. cruzi was performed through qPCR amplification using satellite oligonucleotides. Of the 349 blood samples, 267 (77%) were positive, with parasite loads ranging between <0.10 and 10.90 par-eq/mL (median 0.10). In spring, frequencies of infection in the three departments ranged between 86% and 95%, but differences were not significant. Median parasite loads were higher in Lavalle than in the other departments, while those in goats from San Carlos were consistently low. The frequency of infection and parasite loads in Malargüe were significantly higher in spring than in fall. This seasonal variation may have been related to a reduced nutritional status and impaired immune response of goats in spring. In conclusion, the high proportion of positive goats confirms the persistence of T. cruzi in rural Mendoza.
Atmospheric Research, 2019
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
International Journal of Climatology, 2019
Daily precipitation concentration in the Amazon basin (AB) is characterized using concentration i... more Daily precipitation concentration in the Amazon basin (AB) is characterized using concentration index (CI), which is computed from HYBAM Observed Precipitation (HOP) data set, for 1980-2009 period. The ability of four satellite precipitation data sets (TMPA V7, TMPA RT, CMORPH and PERSIANN) to estimate CI is evaluated for 2001-2009 period. Our findings provide new information about the spatial irregularity of daily rainfall distribution over the AB. In addition, the spatial distribution of CI values is not completely explained by rainfall seasonality, which highlights the influence of different weather systems over the AB. The results of rainfall concentration indicate that the distribution of daily rainfall is more regular over northwest (northern Peru) and central Andes. Conversely, Roraima region and a large area of Bolivian Amazon register the highest irregularity in the daily rainfall. Bolivian Amazon also represents regions where the large percentage of total rainfall arises from extreme events (>90th percentile). Heavy rainfall episodes over Roraima region are induced by humidity influx come from Caribbean region, while heavy rainfall events over Bolivian Amazon and Andes region are induced by the northwards propagation of cold and dry air along both sides of Andes Mountains, but only propagate in all tropospheric levels for the Andes. The results also show that PERSIANN and TMPA7 data sets better estimates the daily precipitation concentration for whole AB, but with a relative error 8%. CI estimated from satellites does not agree well with HOP over the Andes and northern Peruvian Amazon. On the other hand, the temporal variability of CI can partly be detected using CMORPH and TMPAV7 data sets over the Peruvian Andes, and central and southern Brazil. Errors in CI estimating might be related to inaccurate estimation of daily rainfall. Finally, we conclude that satellite-based precipitation data sets are useful for analysing rainfall concentration in some regions of AB.
Acta Tropica, 2018
Trypanosoma cruzi, and transmitted by triatomine insects to several mammal species. In Chile, the... more Trypanosoma cruzi, and transmitted by triatomine insects to several mammal species. In Chile, the wild triatomine species are the endemic Mepraia species, and the only domestic vector of Chagas disease is Triatoma infestans. The aim of this study was to determine the competence of M. gajardoi compared to T. infestans as a T. cruzi vector using the naturally infected rodent Octodon degus. M. gajardoi amplified T. cruzi present in all O. degus studied while T. infestans only in half of the infected rodents. Both triatomine species excrete metacyclic trypomastigotes and amplified the same three T. cruzi DTUs, however, M. gajardoi showed differences in their ability to amplify TcI. TcV and TcVI had the same probability to be amplified by both triatomine species. Both species amplified mixed infections, with TcI-TcVI as the most represented. This study reports the higher vector competence of M. gajardoi in
Revista Cientifica TECNIA, 2017
Los altos porcentajes de concentración de precipitación diaria en pocos días, pueden incrementar ... more Los altos porcentajes de concentración de precipitación diaria en pocos días, pueden incrementar el potencial de erosión, inestabilidad de laderas y riesgo de inundaciones, siendo estos problemas comunes en el Perú, por lo que es importante el conocimiento acerca de la precipitación a nivel diario. En este articulo, se ha llevado a cabo una investigación acerca de los patrones espaciales y temporales de la concentración de precipitación diaria en los andes centrales del Perú, mediante el índice de concentración (IC), que evalúa la variación de la valoración de precipitación diaria, la contribución de grandes lluvias a la cantidad total presentada. El índice es aplicado a una curva exponencial como Y = aX exp(bX ) , el cual ajusta el porcentaje acumulado de precipitación en Y contribuida por el porcentaje acumulado de días X llevado a cabo en un lugar, en el periodo 1964-2004, con el cual es posible generar superficies de concentración pluviométrica. Donde las máximas concentraciones...
Parasites & vectors, Jan 7, 2017
Chagas disease caused by Trypanosoma cruzi is considered a major public health problem in America... more Chagas disease caused by Trypanosoma cruzi is considered a major public health problem in America. After an acute phase the disease changes to a chronic phase with very low parasitemia. The parasite presents high genetic variability with seven discrete typing units (DTUs): TcI-TcVI and Tc bat. The aim of this work is to evaluate fluctuation of parasitemia and T. cruzi DTUs in naturally infected Octodon degus. After animal capture parasitemia was obtained by qPCR and later the animals were evaluated by three serial xenodiagnoses using two insect vector species, Mepraia spinolai and Triatoma infestans. The parasites amplified over time by insect xenodiagnosis were analyzed by conventional PCR and after that the infective T. cruzi were characterized by means of hybridization tests. The determination of O. degus parasitemia before serial xenodiagnosis by qPCR reveals a great heterogeneity from 1 to 812 parasite equivalents/ml in the blood stream. The T. cruzi DTU composition in 23 analy...
![Research paper thumbnail of [What do the numbers tell us about the temporal evolution of Chagas' disease?]](https://attachments.academia-assets.com/98242169/thumbnails/1.jpg)
Revista chilena de infectologia : organo oficial de la Sociedad Chilena de Infectologia, 2017
Chagas disease remains highly prevalent in Chile, especially between the regions of Arica and Par... more Chagas disease remains highly prevalent in Chile, especially between the regions of Arica and Parinacota, and Coquimbo. Since 1999 it is considered that in Chile the vector transmission was interrupted. Under this premise, the epidemiological dynamics should be changing. We analyzed the evolution of the prevalence of Chagas' disease analyzing 64,995 xenodiagnosis performed in the laboratory of Parasitology of the Faculty of Medicine of the University of Chile between 1949 and 2014. The evolution of the mortalities and incidences from the databases of the Ministry of Health in the periods in which it was analyzed. The rates of domiciliary infestation and the number of vector insects sent to the Public Health Institute and its trypano-triatomine indices were also analyzed. The prevalence of Chagas' disease in inhabitants of risk areas remained stable in this period as well as mortality. The incidence rate shows a progressive increase with a tendency towards stabilization. A si...
Parasites & vectors, Jul 4, 2016
Trypanosoma cruzi multiplies and differentiates in the digestive tract of triatomine insects. Xen... more Trypanosoma cruzi multiplies and differentiates in the digestive tract of triatomine insects. Xenodiagnosis (XD) is a parasitological tool in which the insect vectors acts as a biological culture medium to amplify and detect T. cruzi infection in mammals. The sensitivity of XD has been overcome by the application of PCR in fecal samples (FS) of XD (PCR-XD). In this study, T. cruzi amplified in Triatoma infestans fed by XD on individuals with chronic Chagas disease (CChD) is quantified by real-time PCR (qPCR-XD). Under informed consent, 100 individuals were evaluated. In 21 of them XD, PCR-XD and qPCR-XD were positive. For the contrary, 79 were negative XD. In 58 (73.4 %) and 66 cases (83.5 %) of them, PCR-XD (Fisher's exact test P = 0.005) and qPCR-XD (Fisher's exact test: P = 0.037) respectively, were positive. In cases with positive XD, qPCR-XD allowed to establish that in 9/21 cases (42.9 %) the parasite burden fluctuated between 100 and 1,000 par. eq./ml. Otherwise, in 3...
Stochastic Environmental Research and Risk Assessment, 2016
The analysis of annual or seasonal data can lead to misinterpretation of spatio-temporal rainfall... more The analysis of annual or seasonal data can lead to misinterpretation of spatio-temporal rainfall distribution. A high percentage of total annual precipitation can fall in just a few days, causing floods or landslides. Large economic losses from these events are particularly common in Peru, where the daily precipitation has been poorly investigated. This study presents a spatio-temporal analysis of concentration index over the Mantaro River basin in the central Peruvian Andes. Daily rainfall data recorded at 46 rainfall stations between 1974 and 2004 were selected in this study. In terms of average values, the analysis of daily rainfall indicates that low-intensity events account for 38 % of rainy days but only approximately 9 % of the total rain amount. In contrast, high- and very high-intensity events account for 35 % of rainy days and approximately 71 % of the total rain amount. The results also indicate higher concentration and lower intensity over the Northern and Central regions, compared to Southern region of the basin. Rainfall concentration gives evidence of why some of these places are more likely to be affected by extreme weather events; spatial distribution of event intensity can be partly explained by daily rainfall heterogeneity and orography. Moreover, Mann–Kendall test mostly shows a significant change toward a weaker seasonality of daily precipitation distribution over high-mountain regions.
The aim of this work is to analyze the differences between players of a group following a token e... more The aim of this work is to analyze the differences between players of a group following a token economy program and another who does not follow it. The results indicate that young players perceive that their trainers have a preference for attacking actions during the match; this unanimity in preferences disappears during training. Significant differences were found significant differences in the preferences of coach during training; which means that belonging to one group of study implies different choices. There have been found significant differences between groups in specific skills related to defense and ball reception.
Uploads
Papers by miguel saavedra