2,321 research outputs found

    Expected geoneutrino signal at JUNO

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    Constraints on the Earth's composition and on its radiogenic energy budget come from the detection of geoneutrinos. The KamLAND and Borexino experiments recently reported the geoneutrino flux, which reflects the amount and distribution of U and Th inside the Earth. The KamLAND and Borexino experiments recently reported the geoneutrino flux, which reflects the amount and distribution of U and Th inside the Earth. The JUNO neutrino experiment, designed as a 20 kton liquid scintillator detector, will be built in an underground laboratory in South China about 53 km from the Yangjiang and Taishan nuclear power plants. Given the large detector mass and the intense reactor antineutrino flux, JUNO aims to collect high statistics antineutrino signals from reactors but also to address the challenge of discriminating the geoneutrino signal from the reactor background.The predicted geoneutrino signal at JUNO is 39.7 5.2+6.5^{+6.5}_{-5.2} TNU, based on the existing reference Earth model, with the dominant source of uncertainty coming from the modeling of the compositional variability in the local upper crust that surrounds (out to \sim 500 km) the detector. A special focus is dedicated to the 6{\deg} x 4{\deg} Local Crust surrounding the detector which is estimated to contribute for the 44% of the signal. On the base of a worldwide reference model for reactor antineutrinos, the ratio between reactor antineutrino and geoneutrino signals in the geoneutrino energy window is estimated to be 0.7 considering reactors operating in year 2013 and reaches a value of 8.9 by adding the contribution of the future nuclear power plants. In order to extract useful information about the mantle's composition, a refinement of the abundance and distribution of U and Th in the Local Crust is required, with particular attention to the geochemical characterization of the accessible upper crust.Comment: Slight changes and improvements in the text,22 pages, 4 Figures, 3 Tables. Prog. in Earth and Planet. Sci. (2015

    Regional study of the Archean to Proterozoic crust at the Sudbury Neutrino Observatory (SNO+), Ontario: Predicting the geoneutrino flux

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    The SNO+ detector, a new kiloton scale liquid scintillator detector capable of recording geoneutrino events, will define the strength of the Earth radiogenic heat. A detailed 3-D model of the regional crust, centered at SNO+ and based on compiled geological, geophysical and geochemical information, was used to characterize the physical and chemical attributes of crust and assign uncertainties to its structure. Monte Carlo simulations were used to predict the U and Th abundances and uncertainties in crustal lithologies and to model the regional crustal geoneutrino signal originating from the at SNO+

    Exploring atmospheric radon with airborne gamma-ray spectroscopy

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    222^{222}Rn is a noble radioactive gas produced along the 238^{238}U decay chain, which is present in the majority of soils and rocks. As 222^{222}Rn is the most relevant source of natural background radiation, understanding its distribution in the environment is of great concern for investigating the health impacts of low-level radioactivity and for supporting regulation of human exposure to ionizing radiation in modern society. At the same time, 222^{222}Rn is a widespread atmospheric tracer whose spatial distribution is generally used as a proxy for climate and pollution studies. Airborne gamma-ray spectroscopy (AGRS) always treated 222^{222}Rn as a source of background since it affects the indirect estimate of equivalent 238^{238}U concentration. In this work the AGRS method is used for the first time for quantifying the presence of 222^{222}Rn in the atmosphere and assessing its vertical profile. High statistics radiometric data acquired during an offshore survey are fitted as a superposition of a constant component due to the experimental setup background radioactivity plus a height dependent contribution due to cosmic radiation and atmospheric 222^{222}Rn. The refined statistical analysis provides not only a conclusive evidence of AGRS 222^{222}Rn detection but also a (0.96 ±\pm 0.07) Bq/m3^{3} 222^{222}Rn concentration and a (1318 ±\pm 22) m atmospheric layer depth fully compatible with literature data.Comment: 17 pages, 8 figures, 2 table

    Direct conversion of mouse embryonic fibroblasts into functional keratinocytes through transient expression of pluripotency-related genes

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    The insufficient ability of specialized cells such as neurons, cardiac myocytes, and epidermal cells to regenerate after tissue damage poses a great challenge to treat devastating injuries and ailments. Recent studies demonstrated that a diverse array of cell types can be directly derived from embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), or somatic cells by combinations of specific factors. The use of iPSCs and direct somatic cell fate conversion, or transdifferentiation, holds great promise for regenerative medicine as these techniques may circumvent obstacles related to immunological rejection and ethical considerations. However, producing iPSC-derived keratinocytes requires a lengthy two-step process of initially generating iPSCs and subsequently differentiating into skin cells, thereby elevating the risk of cellular damage accumulation and tumor formation. In this study, we describe the reprogramming of mouse embryonic fibroblasts into functional keratinocytes via the transient expression of pluripotency factors coupled with directed differentiation. The isolation of an iPSC intermediate is dispensable when using this method. Cells derived with this approach, termed induced keratinocytes (iKCs), morphologically resemble primary keratinocytes. Furthermore they express keratinocyte-specific markers, downregulate mesenchymal markers as well as the pluripotency factors Oct4, Sox2, and Klf4, and they show important functional characteristics of primary keratinocytes. iKCs can be further differentiated by high calcium administration in vitro and are capable of regenerating a fully stratified epidermis in vivo. Efficient conversion of somatic cells into keratinocytes could have important implications for studying genetic skin diseases and designing regenerative therapies to ameliorate devastating skin conditions.COST (European Cooperation in Science and Technology) (EU-COST Action BM1302 “Joining Forces in Corneal Regeneration Research”)University of Cypru

    Nod2 Deficiency in mice is Associated with Microbiota Variation Favouring the Expansion of mucosal CD4+ LAP+ Regulatory Cells

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    Nucleotide-binding Oligomerization Domain-2 (NOD2) mutations are associated with an increased risk to develop Crohn's Disease. In previous studies, we have shown that Nod2-/- mice manifest increased proportion of Lamina Propria (LP) CD4+ LAP+ Foxp3- regulatory cells, when compared with Nod2+/+ mice, while CD4+ Foxp3 + regulatory cells were not affected. Here, we investigated the Nod2 gut microbiota, by 16S rRNA pyrosequencing, at steady state and after TNBS-colitis induction in mice reared separately or in cohousing, correlating the microbial profiles with LP regulatory T cells proportion and tissue cytokines content. We found that enrichment of Rikenella and Alistipes (Rikenellaceae) in Nod2-/- mice at 8 weeks of age reared separately was associated with increased proportion of CD4+ LAP+ Foxp3- cells and less severe TNBS-colitis. In co-housed mice the acquisition of Rickenellaceae by Nod2+/+ mice was associated with increased CD4+ LAP+ Foxp3- proportion and less severe colitis. Severe colitis was associated with enrichment of gram-negative pathobionts (Escherichia and Enterococcus), while less severe colitis with protective bacteria (Barnesiella, Odoribacter and Clostridium IV). Environmental factors acting on genetic background with different outcomes according to their impact on microbiota, predispose in different ways to inflammation. These results open a new scenario for therapeutic attempt to re-establish eubiosis in Inflammatory Bowel Disease patients with NOD2 polymorphisms

    Geoneutrinos and reactor antineutrinos at SNO+

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    In the heart of the Creighton Mine near Sudbury (Canada), the SNO+ detector is foreseen to observe almost in equal proportion electron antineutrinos produced by U and Th in the Earth and by nuclear reactors. SNO+ will be the first long baseline experiment to measure a reactor signal dominated by CANDU cores (\sim55\% of the total reactor signal), which generally burn natural uranium. Approximately 18\% of the total geoneutrino signal is generated by the U and Th present in the rocks of the Huronian Supergroup-Sudbury Basin: the 60\% uncertainty on the signal produced by this lithologic unit plays a crucial role on the discrimination power on the mantle signal as well as on the geoneutrino spectral shape reconstruction, which can in principle provide a direct measurement of the Th/U ratio in the Earth.Comment: 7 pages including 2 figures and 1 table, in XIV International Conference on Topics in Astroparticle and Underground Physics (TAUP 2015) IOP Publishing , published on Journal of Physics: Conference Series 718 (2016) 06200

    A century of oil and gas exploration in Albania: assessment of Naturally Occurring Radioactive Materials (NORMs)

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    Because potential Naturally Occurring Radioactive Materials (NORMs) generated from oil and gas extractions in Albania have been disposed without regulatory criteria in many decades, an extensive survey in one of the most productive regions (Vlora-Elbasan) has been performed. Among 52 gamma-ray spectrometry measurements of soil, oil-sand, sludge, produced water and crude oil samples, we discover that relatively low activity concentrations of 226Ra, 228Ra, 228Th and 40K, which are 23 +/- 2 Bq/kg, 23 +/- 2 Bq/kg, 24 +/- 3 Bq/kg and 549 +/- 12 Bq/kg, respectively, come from oil-sand produced by hydrocarbon extraction from molasses formations. The mineralogical characterization together with the 228Ra/40K and 226Ra/40K ratios of these Neogene deposits confirm the geological and geodynamic model that predicts a dismantling of Mesozoic source rocks. The average activity concentrations (+/- standard deviations) of the radium isotopes (226Ra, 228Ra) and of the 228Th and 40K radionuclides in soil samples are determined to be 20 +/- 5 Bq/kg, 25 +/- 10 Bq/kg, 25 +/- 9 Bq/kg and 326 +/- 83 Bq/kg, respectively. Based on these arguments, the future radiological assessment of other fields in the region can be strategically planned focusing on the oil-sands from molasses sediments. No disequilibrium in the 228Ra decay segment has been observed in soil, sludge and oil-sand samples within the standard uncertainties. After a detailed radiological characterization of the four main oilfields, we can conclude that the outdoor absorbed dose rate never exceeds the worldwide population weighted average absorbed dose rate in outdoor air from terrestrial gamma radiation.Comment: 21 pages, 5 figures, 2 tables, Chemosphere 201

    Empirical Challenges in Organizational Aesthetics Research: Towards a Sensual Methodology

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    Despite growing scholarly interest in aesthetic dimensions of organizational life, there is a lack of literature expressly engaging with the methodological mechanics of 'doing aesthetics research'. This article addresses that gap. It begins with an overview of the conceptual idiosyncrasies of 'aesthetics' as a facet of human existence and maps out the challenges these pose for empirical research methodology. A review of methodological approaches adopted to date in empirical studies of organizational aesthetics is then presented. The remainder of the article draws on the author's experiences and suggests methods and techniques to address both conceptual and practical challenges encountered during the execution of an organizational aesthetics research project. The article calls for a firmer focus on the aesthetic experiences of organizational members in addition to those of researchers and concludes with some suggestions as to the future of such 'sensual methodologies' </jats:p

    Training Future Engineers to Be Ghostbusters: Hunting for the Spectral Environmental Radioactivity

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    Although environmental radioactivity is all around us, the collective public imagination often associates a negative feeling to this natural phenomenon. To increase the familiarity with this phenomenon we have designed, implemented, and tested an interdisciplinary educational activity for pre-collegiate students in which nuclear engineering and computer science are ancillary to the comprehension of basic physics concepts. Teaching and training experiences are performed by using a 4" x 4" NaI(Tl) detector for in-situ and laboratory {\gamma}-ray spectroscopy measurements. Students are asked to directly assemble the experimental setup and to manage the data-taking with a dedicated Android app, which exploits a client-server system that is based on the Bluetooth communication protocol. The acquired {\gamma}-ray spectra and the experimental results are analyzed using a multiple-platform software environment and they are finally shared on an open access Web-GIS service. These all-round activities combining theoretical background, hands-on setup operations, data analysis, and critical synthesis of the results were demonstrated to be effective in increasing students' awareness in quantitatively investigating environmental radioactivity. Supporting information to the basic physics concepts provided in this article can be found at http://www.fe.infn.it/radioactivity/educational
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