2,321 research outputs found
Expected geoneutrino signal at JUNO
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 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
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
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
Rn is a noble radioactive gas produced along the U decay
chain, which is present in the majority of soils and rocks. As 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,
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 Rn as a source of background since
it affects the indirect estimate of equivalent U concentration. In this
work the AGRS method is used for the first time for quantifying the presence of
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 Rn. The refined statistical analysis provides not only a
conclusive evidence of AGRS Rn detection but also a (0.96 0.07)
Bq/m Rn concentration and a (1318 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
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
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+
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 (55\% 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)
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
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
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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