5 results on '"Martínez, S."'
Search Results
2. U-Pb Ages of Detrital Zircons from the Permo-Triassic Series of the Iberian Ranges: A Record of Variable Provenance during Rift Propagation.
- Author
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Martínez, S. Sánchez, de la Horra, R., Arenas, R., Gerdes, A., Galán-Abellán, A. B., López-Gómez, J., Barrenechea, J. F., and Arche, A.
- Subjects
ZIRCON ,GEOLOGICAL time scales ,LAKE sediments ,PALEOCURRENTS ,SANDSTONE ,RIFTS (Geology) - Abstract
The provenance of the Permo-Triassic series of the Talayuelas anticline (Iberian Ranges) have been studied using U-Pb geochronology (laser ablation inductively coupled plasma mass spectrometry) of detrital zircons. These intracontinental siliciclastic series were formed by extensive sandy braided fluvial systems associated with ephemeral lake deposits and aeolian sediments, with paleocurrents suggesting constant NW-SE transport directions. Upper Permian reddish sandstones from the Upper Alcotas Formation (Lopingian) contain a dominant Variscan zircon population (290-360 Ma), which indicates source areas located in the axial zone of the Variscan belt, in the core of the Ibero-Armorican arc. However, in the Lower Triassic sandstones of the Cañizar Formation (Olenekian), the Variscan zircon population is almost completely replaced by Cadomian zircons (520-750 Ma), with important Avalonian (390-520 Ma), Mesoproterozoic (900-1750 Ma), Eburnian (1.78-2.35 Ga), and post-Eburnian and Archaean (>2.4 Ga) zircon populations. This detrital zircon content now suggests source areas located more to the NW, in the Avalonian microcontinent, although a limited supply coming from the southern part of Laurentia cannot be ruled out. Finally, in the Middle Triassic (Anisian), the source areas returned to the Variscan axial zone, since the Variscan zircon population is again highly dominant during this period. The changes detected in the source areas of the Permo-Triassic series are related to the development and propagation of the Iberian rift, one of the large extensional structures that determined the generation of the sedimentary basins and finally caused the breakup of Pangea. The methodology followed in this article is very useful to understand the generation and evolution of these intracontinental basins and also the relationships between the different rift systems generated in the North Atlantic realm during the Permo-Triassic times. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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3. Seroinfection of Antibodies to Toxoplasma gondii , Parvovirus B19, Treponema pallidum , and HIV in a Pregnant Attending a Medical Center in Northern Peru.
- Author
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Cubas-Alarcón D, Guevara-Vásquez GM, Suclupe-Campos DO, Castro-Martínez S, Aguilar-Gamboa FR, and Failoc-Rojas VE
- Subjects
- Humans, Female, Pregnancy, Peru epidemiology, Adult, Cross-Sectional Studies, Young Adult, Antibodies, Protozoan blood, Antibodies, Viral blood, Adolescent, Seroepidemiologic Studies, Treponema pallidum immunology, Syphilis epidemiology, Pregnancy Complications, Infectious epidemiology, Pregnancy Complications, Infectious virology, Toxoplasmosis epidemiology, Toxoplasmosis immunology, HIV Infections epidemiology, Toxoplasma immunology, Parvovirus B19, Human immunology
- Abstract
Introduction: Transplacental infections are frequent, especially in developing countries, where limited screening is performed to find infectious agents in the pregnant population. We aim to determine the clinical and epidemiological characteristics and seroinfection of antibodies against Toxoplasma , parvovirus B19, T. pallidum , and HIV in pregnant women who attended the Motupe Health Center in Lambayeque, Peru during July-August 2018., Methods: A descriptive cross-sectional study was conducted in 179 pregnant women interviewed with a standardized questionnaire. ELISA was used to determine antibodies to Toxoplasma and parvovirus B19. The detection of syphilis and HIV was conducted using immunochromatography, while the detection of hepatitis B was conducted using FTA-ABS and immunofluorescence, respectively., Results: Of 179 pregnant women, syphilis and HIV infections routinely included in the screening of pregnant women presented a seroinfection of 2.2 and 0.6%, respectively. Toxoplasmosis seroinfection was 25.1%, while IgM antiparvovirus B19 was 40.8%, revealing that pregnant women had an active infection at the time of study., Conclusion: The level of seroinfection of toxoplasmosis reveals the risk to which pregnant women who participated in the study are exposed. The high seroinfection of parvovirus B19 could explain the cases of spontaneous abortion and levels of anemia in newborn that have been reported in Motupe, Lambayeque, Peru. However, future causality studies are necessary to determine the significance of these findings., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2024 Deniss Cubas-Alarcón et al.)
- Published
- 2024
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4. Prevalence of strongyloidiasis in Peru: systematic review and meta-analysis.
- Author
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Ortiz-Martínez S, Ramos-Rincón JM, Vásquez-Chasnamote ME, Gamboa-Paredes ON, Arista-Flores KM, Espinoza-Venegas LA, de-Miguel-Balsa E, Pinedo-Cancino VV, Górgolas-Hernández-Mora M, and Casapía-Morales M
- Subjects
- Animals, Feces, Humans, Peru epidemiology, Prevalence, Strongyloides stercoralis, Strongyloidiasis diagnosis, Strongyloidiasis epidemiology
- Abstract
Background: Strongyloidiasis is a disease of great public health significance, caused by the parasitic nematodes Strongyloides stercoralis, Strongyloides fuelleborni, and Strongyloides fuelleborni subsp. kellyi. This systematic review and meta-analysis aimed to assess the prevalence of Strongyloides stercoralis infection in Peru., Methods: The review was based on a literature search in PubMed, SciELO and Google Scholar using the key words or root words "strongyl*" AND "Peru" on 15 July 2020. Eligible studies were published from 1 January 1981 to 15 July 2020 and written in English, Spanish, Italian, or French., Results: We included 21 papers in the analysis. Studies were heterogeneous in terms of study population and diagnostic methods (e.g. Baermann technique, agar, Dancescu or charcoal cultures, serology, string capsule). Prevalence of S. stercoralis ranged from 0.3 to 45%. The pooled proportion of Strongyloides in the general population was 7.34% (95% CI 4.97 to 10.13%). Half the studies were designed to detect parasites in general. In studies designed to detect S. stercoralis, the most widely used diagnostic method was the Baermann technique., Conclusion: Prevalence of S. stercoralis in Peru was high but varied by geographic area, techniques for stool examination, and participant characteristics., (© 2021. The Author(s).)
- Published
- 2021
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5. [Gasometric values reported in healthy subjects from the Mexican population: review and analysis].
- Author
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Pérez Martínez SO and Pérez-Padilla JR
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- Adult, Air analysis, Arteries, Atmospheric Pressure, Capillaries, Child, Humans, Mexico, Oxygen administration & dosage, Partial Pressure, Peru, Physical Exertion, Reference Values, United States, Urban Population, Adaptation, Physiological genetics, Altitude, Carbon Dioxide analysis
- Abstract
We do not know the normal relationship between altitude and PaCO2 in Mexico. We collected and analyzed the reports of reference values for gasometry in Mexico City (2240 m above sea level and a mean barometric pressure of 585 Torr) and other places in the country. The reports include arterial, capillary and expired gases in children and adults, with measurements done in resting and exercising subjects, breathing room air and 100% oxygen. In Mexico City we found 18 studies in normal subjects reporting a mean PaCO2 ranging from 25.5 to 38.4 Torr. Averaging arterial studies from children and adults, adjusting for the number of subjects studied, and discarding data with mean pH below 7.37 or above 7.43 (suggesting non steady state), 10 studies with a total of 581 subjects have the following average values (Torr, means and SD): PaCO2 = 31.1 +/- 2.6, PaO2 = 67.7 +/- 2.6, calculated PAO2 and P(A-a)O2 73.6 +/- 3.3 y 6.1 +/- 3.7 respectively. The PaCO2 found was much lower than that reported for native Peruvians in the Andes who have a mean PaCO2 of 37.8 Torr at an altitude of 2390 m, and a mean PaCO2 of 33.0 Torr only at 4860 m above the sea level. On the other hand, the average values in Mexico are similar to those found in North Americans who have a mean PACO2 of 33.1 Torr at 2131 m of altitude, a mean PACO2 of 30.7 at 2371 m and a mean PaCO2 of 31 Torr at 2238 m. Normal values for gasometry in Mexico are scarce and some of the existing ones are erroneous probably due to lack of adequate calibrations and to poor quality control. Values of PaCO2 in Mexico are more similar to those found in the USA than to those found in Peruvian natives.
- Published
- 1992
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