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Assessment of Present and Future Radioactive Contamination at Global Scale

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Journal of Chemistry and Chemical Engineering 2012年第11期6卷 1010-1015页

作者： juan manuel navarrete Miguel Angel ZUNiga Guillermo Espinosa Jose Ignacio Golzarri Faculty of Chemistry National University of Mexico Mexico City 04510 Mexico Institute of Physics National University of Mexico Mexico City 04510 Mexico

As a result of more than two thousand nuclear tests performed since 1945, two war actions and few accidents in nuclear reactor, it does already exist a radioactive contamination at global scale. This contamination has been accumulated mainly in marine sediments, because sea is about 80% of planet surface, and solid fission products released by nuclear explosions are transported by wind first and then by rain to liquid and solid portions on earth, while gaseous fission products are diffused in the atmosphere. In this way, heavy, high yielding fission products, such as 137Cs, get marine sediments, where they are found mixed with heavy radioactive natural elements such as U, Th and their also radioactive decay products. But since alkaline are so abundant on earth, it is also found natural radioactive isotope 40K, 0.0118% of isotopes forming K element, with half life 1.28 × 109, in the time range of planet age and elements origin. So, one easy way to assess both the importance and evaluation of radioactive contamination at global scale should be to establish a RCF (radioactive contamination factor) as a percentage of 137Cs contaminant radioactivity in marine sediments, compared to 40K natural radioactivity present from the very beginning of earth, both expressed as Bq per gram of sediment. In the frame of these rather general considerations, a research project has started in Mexico whose varied purposes are: to characterize sea regions in both vast littorals in the country, by its natural 40K radioactivity present in sea salts, as well as to determine if 137Cs traces produced by recent radioactive contamination have reached their coasts. Also, to assess the 137Cs traces already present in marine sediments as a result of more than two thousand nuclear test explosions performed till now, rather than contamination produced by four main accidents in nuclear reactors during the last 60 years. It is proposed a radioactive contamination factor obtained from samples taken up in both coasts during the last two years, which sh

关键词：放射性污染全球范围评估天然放射性水平海洋沉积物铯-137 反应堆事故裂变产物

Isobars Separation (137Cs-137mBa-137Ba) from Marine Sediments, in Order to Evaluate Directly Their Radioactive Contamination by Mass Spectrometry

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World Journal of Nuclear Science and Technology 2020年第1期10卷 32-38页

作者： Karla Fernández juan manuel navarrete Miguel Angel Zúñ iga Ernesto Hernández Department of Inorganic and Nuclear Chemistry Faculty of ChemistryNational Autonomous University of MexicoMexico CityMexico

Marine sediments contamination by fission product 137Cs-137mBa is a fact since the period 1945-65, when plus than two thousand atomic explosion tests were performed mainly in the southern seas, earth region with minor population density. However, marine flows have produced dissemination of this radioactive pair through the sea bottom all over the world, at different levels, because the sea movement and natural decaying of radioactive pair: parent 137Cs (t1/2 = 30.17 years) and daughter 137mBa (t1/2 = 2.55 minutes). Radioactive detection of these contaminants, compared as percentage with that of natural 40K (t1/2 = 1.28 × 109 years, 0.0118% of elementary K) leads to radiation contamination factor (RCF), as one possible unit to measure the radioactive contamination intensity in different regions, as well to determine if there is some other possible source of this contaminant, for example water cooling from power nuclear reactors when it is discharged at sea. However, radioactive detection always implies an unavoidable statistical variation, which makes more difficult to appreciate the changes as function of time and region. But at beginning of this century, mass spectrometry has got impressive advances, which makes it much more precise and sensible than radioactive detection [1]. This paper attempts to measure with other units the radioactive contamination: 137Cs atoms number per gram of sample, instead radioactivity, which could be more direct and with minor standard deviation that radioactive detection, solving at same time the isobars separation: 137Cs versus 137mBa plus elementary 137Ba (11.23% of Ba element).

关键词： Isobars Separation 137Cs-137mBa-137Ba

Prevalence and ecological factors affecting the distribution of plant-parasitic nematodes in Prunus groves in Spain

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Journal of Integrative Agriculture 2024年第2期23卷 566-589页

作者： Ilenia Clavero-Camacho Antonio Archidona-Yuste Carolina Cantalapiedra-navarrete Pablo Castillo juan Emilio Palomares-Rius Institute for Sustainable Agriculture(IAS) Spanish National Research Council(CSIC)Córdoba 14004Spain Andalusian Institute of Agricultural and Fisheries Research and Training(IFAPA) Centro Alameda del ObispoCórdoba 14004Spain

A wide survey was conducted to study plant-parasitic nematodes(PPNs)associated with Prunus groves in Spain.This research aimed to determine the prevalence and distribution of PPNs in Prunus groves,as well as the influence of explanatory variables describing soil,climate and agricultural management in structuring the variation of PPNs community composition.A total of 218 sampling sites were surveyed and 84 PPN species belonging to 32 genera were identified based of an integrative taxonomic approach.PPN species considered as potential limiting factors in Prunus production,such as Meloidogyne arenaria,M.incognita,M.javanica,Pratylenchus penetrans and P.vulnus,were identified in this survey.Seven soil physico-chemical(C,Mg,N,Na,OM,P,pH and clay,loamy sand and sandy loam texture classes),four climate(Bio04,Bio05,Bio13 and Bio14)and four agricultural management variables(grove-use history less than 10 years,irrigation,apricot seedling rootstock,and Montclar rootstock)were identified as the most influential variables driving spatial patterns of PPNs communities.In particular,younger plantations showed higher values for species richness and diversity indices than groves cultivated for more than 20 years with Prunus spp.Our study increases the knowledge of the distribution and prevalence of PPNs associated with Prunus rhizosphere,as well as on the influence of explanatory variables driving the spatial structure PPNs communities,which has important implications for the successful design of sustainable management strategies in the future in this agricultural system.

关键词： nematodes Meloidogyne Pratylenchus Paratylenchus rootstock distribution soil grove-use almond peach

Brent vs.West Texas Intermediate in the US petro derivatives price formation

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Petroleum Science 2024年第1期21卷 729-739页

作者： Alejandro Almeida Antonio A.Golpe juan manuel Martín-Alvarez Jose Carlos Vides Universidad Internacional de La Rioja Department of Quantitative Methods for Economics and BusinessLa RiojaSpain University of Huelva Department of Economics and Centro de Estudios Avanzados en FisicaMatematicas y Computacion and ICEIHuelvaSpain Complutense University of Madrid Department of Applied and Structural Economics and History and ICEIMadridSpain

In this paper,we apply the spatial panel model to explore the relationship between the dynamic of two types of crude oil prices(WTI and Brent crude oil)and their refined products over time.Considering the turbulent months of 2011,when Cushing Oklahoma had reached capacity and the crude oil export ban removal in 2015 as breakpoints,we apply this method both in the full sample and the three resultant regimes.First,results suggest our results show that both WTI and Brent display very similar behaviour with the refined products.Second,when attending to each regime,results derived from the first and third regimes are quite similar to the full sample results.Therefore,during the second regime,Brent crude oil became the benchmark in the petrol market,and it influenced the distillate products.Furthermore,our model can let us determine the price-setters and price-followers in the price formation mechanism through refined products.These results possess important considerations to policymakers and the market participants and the price formation.

关键词： Crude oil prices Spatial panel model Refined products Price formation

Determination of Radioactive Contaminant ¹³⁷Cs (Fission Product) and Comparison with Natural ⁴⁰K Present in Mexican Strawberries

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Journal of Geoscience and Environment Protection 2022年第7期10卷 257-265页

作者： Fridda Concepción Fuentes Gama juan manuel navarrete Tejero Alejandro Ramírez Chávez Miguel Ángel Zúñiga Pérez Department of Inorganic and Nuclear Chemistry Faculty of Chemistry National Autonomous University of Mexico Mexico City Mexico

Several previous papers have been published about radioactive contamination in Mexican soil, marine sediments and foodstuffs. Ever since, results have been according to expectation, mainly consisting of natural isotopes in small concentration. Continuous research leads with the surprising finding of fission product 137Cs (t1/2 = 30 years) in strawberries produced in different states, about 2000 km away from each other. Never before, such contaminant has been observed in foodstuffs, produced in this country. The aim of this work is to report the presence of 137Cs in Mexican strawberries and compare the activity of such contaminant with the natural radioactivity of 40K (t1/2 = 1.28 × 109 years), through gamma spectrometry. Eventually, the specific activity of 137Cs observed in samples FM4, FM5 and FBC is respectively 0.7, 0.8 and 0.3 Bq/kg. The limits established in CODEX-STAN-193-1995 for 137Cs are 1000 Bq/kg, so all samples meet the recommendation. It’s presence now in vegetables result with enough interest to be known and considered in the near future to measure the possible effect that radioactive contamination could reach after nearly 80 years from second world war, where no nuclear test has been performed, nuclear accident occurred, neither nuclear weapon has ever been used.

关键词： Radioactive Contamination

The Limits of Domestic Spatiality in the Information Age-A Secondary Publication

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Journal of World Architecture 2024年第1期8卷 76-82页

作者： juan manuel Lozano de Poo Autonomous University of San Luis Potosí San Luis PotosíMexico

The limits of spatiality have blurred in the information age;a phenomenon that can be observed through the socio-spatial implications of Internet use in the domestic sphere.How and why are the use and organization of space-time around the Internet shaping a new domestic spatiality that intertwines the digital space with the production of social space through the practice of habits,presence,and interaction of individuals?What are the repercussions of the superimposition of digital space on human existence?The units of analysis were integrated through the sum of people and middle-class housing in the face of the digitalization process in the city of San Luis Potosi,Mexico.The questionnaire consisted of 35 questions designed from the Likert scale under the thematic order of presence,interaction,and habituality.The data were analyzed using SPSS software.This research contributes to explaining the current period in the history of inhabitable space,dominated by the simultaneous interrelationships between individuals,digital space,and architecture,which result in the detachment and devaluation of physical domestic space,while also highlighting the lack of control and regulation of individuals over the Internet.

关键词： Graffiti Urban image Legislation Regulations South America

Potassium Concentration by Natural ^40K-^40Ar Y Rays Detection in Four Basic Diet Products （Milk, Eggs, Wheat and Corn）

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Journal of Life Sciences 2011年第8期5卷 614-617页

作者： juan manuel navarrete Trinidad Martinez Luis Cabrera Pilar Lizarraga Miguel Angel Zuniga Michelle Camacho Faculty of Chemistry Building D National University of Mexico CU Mexico City ZC 04510 Mexico

A Probabilistic Description of the Impact of Vaccine-Induced Immunity in the Dynamics of COVID-19 Transmission

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Open Journal of Modelling and Simulation 2024年第2期12卷 59-73页

作者： Javier Blecua juan Fernández-Recio José manuel Gutiérrez Instituto de Ciencias de la Vid y del Vino (ICVV) CSIC-Universidad de La Rioja-Gobierno de La Rioja Logro&#241o Spain Departamento de Matemá ticas y Computaci&#243n Universidad de La Rioja Logro&#241o Spain

The recent outbreak of COVID-19 has caused millions of deaths worldwide and a huge societal and economic impact in virtually all countries. A large variety of mathematical models to describe the dynamics of COVID-19 transmission have been reported. Among them, Bayesian probabilistic models of COVID-19 transmission dynamics have been very efficient in the interpretation of early data from the beginning of the pandemic, helping to estimate the impact of non-pharmacological measures in each country, and forecasting the evolution of the pandemic in different potential scenarios. These models use probability distribution curves to describe key dynamic aspects of the transmission, like the probability for every infected person of infecting other individuals, dying or recovering, with parameters obtained from experimental epidemiological data. However, the impact of vaccine-induced immunity, which has been key for controlling the public health emergency caused by the pandemic, has been more challenging to describe in these models, due to the complexity of experimental data. Here we report different probability distribution curves to model the acquisition and decay of immunity after vaccination. We discuss the mathematical background and how these models can be integrated in existing Bayesian probabilistic models to provide a good estimation of the dynamics of COVID-19 transmission during the entire pandemic period.

关键词： COVID-19 Transmission Dynamics Probabilistic Model Bayesian Analysis Markov Chain Monte Carlo

Promotion of structural plasticity in area V2 of visual cortex prevents against object recognition memory deficits in aging and Alzheimer's disease rodents

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Neural Regeneration Research 2024年第8期19卷 1835-1841页

作者： Irene Navarro-Lobato Mariam Masmudi-Martín manuel F.López-Aranda juan F.López-Téllez Gloria Delgado Pablo Granados-Durán Celia Gaona-Romero Marta Carretero-Rey Sinforiano Posadas María E.Quiros-Ortega Zafar U.Khan Laboratory of Neurobiology Centro de Investigaciones Médico Sanitarias(CIMES)University of MalagaMalagaSpain Department of Medicine Faculty of MedicineUniversity of MalagaMalagaSpain Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas(CIBERNED) Institute of Health Carlos IIIMadridSpain the Donders Institute for Brain Cognition and Behaviour Radboud UniversityNijmegenThe Netherlands the Brain Metastasis Group National Cancer Research Centre(CNIO)MadridSpain the Department of Neurobiology University of California-Los AngelesLos AngelesCAUSA

Memory deficit,which is often associated with aging and many psychiatric,neurological,and neurodegenerative diseases,has been a challenging issue for treatment.Up till now,all potential drug candidates have failed to produce satisfa ctory effects.Therefore,in the search for a solution,we found that a treatment with the gene corresponding to the RGS14414protein in visual area V2,a brain area connected with brain circuits of the ventral stream and the medial temporal lobe,which is crucial for object recognition memory(ORM),can induce enhancement of ORM.In this study,we demonstrated that the same treatment with RGS14414in visual area V2,which is relatively unaffected in neurodegenerative diseases such as Alzheimer s disease,produced longlasting enhancement of ORM in young animals and prevent ORM deficits in rodent models of aging and Alzheimer’s disease.Furthermore,we found that the prevention of memory deficits was mediated through the upregulation of neuronal arbo rization and spine density,as well as an increase in brain-derived neurotrophic factor(BDNF).A knockdown of BDNF gene in RGS14414-treated aging rats and Alzheimer s disease model mice caused complete loss in the upregulation of neuronal structural plasticity and in the prevention of ORM deficits.These findings suggest that BDNF-mediated neuronal structural plasticity in area V2 is crucial in the prevention of memory deficits in RGS14414-treated rodent models of aging and Alzheimer’s disease.Therefore,our findings of RGS14414gene-mediated activation of neuronal circuits in visual area V2 have therapeutic relevance in the treatment of memory deficits.

关键词： behavioral performance brain-derived neurotrophic factor cognitive dysfunction episodic memory memory circuit activation memory deficits memory enhancement object recognition memory prevention of memory loss regulator of G protein signaling