Poma Porras, Orlando Alan

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Poma Porras, Orlando Alan
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opoma@upeu.edu.pe
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2004 - 200922010 - 201982020 - 202510

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    Fossil whale preservation implies high diatom accumulation rate in the Miocene–Pliocene Pisco Formation of Peru
    (2004-01-01)
    Leonard R. Brand
    ;
    Raúl Esperante
    ;
    Arthur V. Chadwick
    ;
    Orlando Poma  
    ;
    Merling Alomía
    Research Article| February 01, 2004 Fossil whale preservation implies high diatom accumulation rate in the Miocene–Pliocene Pisco Formation of Peru Leonard R. Brand; Leonard R. Brand 1Department of Natural Sciences, Loma Linda University, Loma Linda, California 92350, USA Search for other works by this author on: GSW Google Scholar Raúl Esperante; Raúl Esperante 2Geoscience Research Institute, Loma Linda, California 92350, USA Search for other works by this author on: GSW Google Scholar Arthur V. Chadwick; Arthur V. Chadwick 3Biology Department, Southwestern Adventist University, Keene, Texas 76059, USA Search for other works by this author on: GSW Google Scholar Orlando Poma Porras; Orlando Poma Porras 4 Universidad Peruana Unión, Carretera Central, km. 19, Ñaña, Lima, Peru Search for other works by this author on: GSW Google Scholar Merling Alomía Merling Alomía 4 Universidad Peruana Unión, Carretera Central, km. 19, Ñaña, Lima, Peru Search for other works by this author on: GSW Google Scholar Geology (2004) 32 (2): 165–168. https://doi.org/10.1130/G20079.1 Article history received: 01 Aug 2003 rev-recd: 29 Oct 2003 accepted: 10 Nov 2003 first online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Leonard R. Brand, Raúl Esperante, Arthur V. Chadwick, Orlando Poma Porras, Merling Alomía; Fossil whale preservation implies high diatom accumulation rate in the Miocene–Pliocene Pisco Formation of Peru. Geology 2004;; 32 (2): 165–168. doi: https://doi.org/10.1130/G20079.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Diatomaceous deposits in the Miocene–Pliocene Pisco Formation contain abundant whales preserved in pristine condition (bones articulated or at least closely associated), in some cases including preserved baleen. The well-preserved whales indicate rapid burial. The 346 whales within ∼1.5 km2 of surveyed surface were not buried as an event, but were distributed uninterrupted through an 80-m-thick sedimentary section. The diatomaceous sediment lacks repeating primary laminations, but instead is mostly massive, with irregular laminations and speckles. There is no evidence for bioturbation by invertebrates in the whale-bearing sediment. Current depositional models do not account for the volume of diatomaceous sediments or the taphonomic features of the whales. These taphonomic and sedimentary features suggest that rapid burial due to high diatom accumulation, in part by lateral advection into protected, shallow embayments, is responsible for the superb preservation of these whales, leading to a higher upper limit on phytoplankton accumulation rates than previously documented. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
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    Observations of electric fields during two partial solar eclipses at the geomagnetic equator
    (2025-12-03)
    Manuel Bravo
    ;
    Joel Hugo Fernandez Rojas  
    ;
    Adriana Godoy
    ;
    Jackson E. Pérez
    ;
    B. Urra
    Abstract. This study presents the first coordinated observations of atmospheric electric field (AEF) and ionospheric plasma drifts during the partial solar eclipses of 2 July 2019 and 14 October 2023, observed near the magnetic equator in Lima, Peru. AEF was measured using a field mill, while ionospheric drifts were obtained from radar observations at the Jicamarca Radio Observatory and local magnetometers. The two events displayed contrasting electrodynamic responses: in 2019, AEF variations were ambiguous due to meteorological fluctuations, while in 2023, clearer weather conditions revealed distinct decreases in both surface AEF and ionospheric vertical drift near maximum obscuration. These results demonstrate the variable nature of eclipse-time electrodynamics and demonstrate that simultaneous measurements of AEF and ionospheric electric field are crucial for elucidating the mechanisms of vertical coupling between atmospheric layers. Such coordinated observations provide preliminary insight into how solar and terrestrial drivers jointly modulate the near-surface electric environment, contributing to a more comprehensive understanding of atmosphere–ionosphere interactions in low-latitude regions.
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    Predictive Model with Machine Learning for Environmental Variables and PM2.5 in Huachac, Junín, Perú
    (2025-03-12)
    Emery Olarte
    ;
    José Antonio Gutiérrez
    ;
    Gwayne Roque
    ;
    Juan J. Soria  
    ;
    Joel Hugo Fernandez Rojas  
    PM2.5 pollution is increasing, causing health problems. The objective of this study was to model the behavior of PM2.5AQI (air quality index) using machine learning (ML) predictive models of linear regression, lasso, ridge, and elastic net. A total of 16,543 records from the Huachac, Junin area in Peru were used with regressors of humidity in % and temperature in °C. The focus of this study is PM2.5AQI and environmental variables. Methods: Exploratory data analysis (EDA) and machine learning predictive models were applied. Results: PM2.5AQI has high values in winter and spring, with averages of 52.6 and 36.9, respectively, and low values in summer, with a maximum value in September (spring) and a minimum in February (summer). The use of regression models produced precise metrics to choose the best model for the prediction of PM2.5AQI. Comparison with other research highlights the robustness of the chosen ML models, underlining the potential of ML in PM2.5AQI. Conclusions: The predictive model found was α = 0.1111111 and a Lambda value λ = 0.150025, represented by PM2.5AQI = 83.0846522 − 10.302222000 (Humidity) − 0.1268124 (Temperature). The model has an adjusted R2 of 0.1483206 and an RMSE of 25.36203, and it allows decision making in the care of the environment.
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    Biodegradation of Low-Density Polyethylene—LDPE by the Lepidopteran Galleria Mellonella Reusing Beekeeping Waste
    (2022-09-09)
    Orlando Poma  
    ;
    Betty Ricce
    ;
    Jeyson Beraún
    ;
    Jackson Edgardo Pérez Carpio
    ;
    Hugo Fernandez  
    Plastic pollution is one of the most serious environmental problems of this century because most plastics are single-use, and once their useful life is over, they become pollutants, since their decomposition takes approximately 100–400 years. The objective of this research is to evaluate the efficacy of low-density polyethylene (LDPE) biodegradation by G. mellonella in the district of Pangoa, Junín, Peru. For the development of the study, the G. mellonella was conditioned in three groups of beekeeping residues (beeswax, balanced diet, and wheat bran); after the conditioning stage, the biodegradation treatment was developed, which consisted of placing the G. mellonella in terrariums with the LDPE, the treatments were carried out at three different times (24, 36, and 48 h). To evaluate the efficacy of biodegradation, two analyses were taken into account: the Raman analysis of the low-density polyethylene samples and the weight reduction of the treated LDPE. The results of the Raman analysis indicated that the best treatment was the one applied with G. mellonella conditioned with beeswax, obtaining a wavelength intensity of 0.45 μ.a., while the weight reduction of the LDPE indicated that the best results were given at 36 h and conditioned with beeswax with a reduction of 236.3 mg. In conclusion, the use of G. mellonella for the biodegradation of low-density polyethylene is effective when it is conditioned with beeswax and the treatment is carried out at 36 h.
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