Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
The influence of geology on elevated radon concentrations in Slovenian schools and kindergartens
Andreja Popit,Janja Vaupoti?
Geologija , 2002,
Abstract: 76 instantaneous indoor radon concentrations above the Slovenian action level of 400 Bqm-3 were selected from the database of 1600 radon concentrations in kindergartens and schools, assembled during the Slovenian National Radon Programme. A relationship wasfound between indoor radon concentrations, and geology of rocks under the foundations (uranium content, permeability, porosity, tectonic fractures) and the quality of building construction.
Reasons for large fluctuation of radon and CO2 levels in a dead-end passage of a karst cave (Postojna Cave, Slovenia)
A. Gregori , J. Vaupoti ,F. Gabrov ek
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2013,
Abstract: Measurements of radon concentration were performed at three geomorphologically different locations in Postojna Cave, Slovenia. In the part of the cave open to visitors, annual average radon activity concentrations of 3255 ± 1190 Bq m 3 and 2315 ± 1019 Bq m 3 were found at the lowest point (LP) and in the Lepe jame (Beautiful Caves, BC), respectively. A much higher average of 25 020 ± 12 653 Bq m 3 was characteristic of the dead-end passage Pisani rov (Gaily Coloured Corridor, GC), in which CO2 concentration also reached very high values of 4689 ± 294 ppm in summer. Seasonal variations of radon and CO2 levels in the cave are governed by convective airflow, controlled mainly by the temperature difference between the cave and the outside atmosphere. The following additional sources of radon and CO2 were considered: (i) flux of geogas from the Earth's crust through fractured rocks (radon and CO2 source), (ii) clay sediments inside the passage (radon source) and (iii) the soil layer above the cave (radon and CO2 source).
Real time radon variation indoors  [PDF]
A. Chávez,N. Segovia
Geofísica internacional , 2002,
Abstract: Real-time indoor radon measurements have been performed in a controlled laboratory located 36 km from Mexico City at 3000 m altitude where experimental radon chambers exist. Radon was evaluated with an ALPHAGUARD equipment above installed at 2 m height from the floor, during a period of two years. Temperature and relative humidity were also recorded. The measuring time was programmed to integrate information every hour. The results showed average radon levels of 40 Bq m-3. Radon fluctuations were correlated mainly with local temperature variations in the building. An anticorrelation of radon with humidity was found in the long term. Radon variations indoors were not influenced by the presence of radon chambers in the laboratory.
Introdu o à dádiva
Godbout J.T.
Revista Brasileira de Ciências Sociais , 1998,
Abstract: O artigo examina, inicialmente, esquemas explicativos fundados nas no es de interesse, de racionalidade e de utilidade, que, sob várias denomina es, gozam, nas ciências humanas, de um "privilégio paradigmático". Embora tais modelos apresentem atrativos inegáveis, possuem limita es evidentes, assim como aqueles ligados ao "outro paradigma" dominante, o holismo. Tais modelos mostram-se incapazes de dar conta de grande parte da a o humana, notadamente da esfera de a o que se pode remeter ao que o autor denomina "sistema de dádiva". Prop e-se, assim, na idéia de dádiva, um modelo explicativo alternativo para os dois paradigmas dominantes, inspirado no pensamento de Marcel Mauss, que nos permitiria partir de pressupostos diferentes, colocar novas quest es e encontrar outras respostas.
Methods of radon measurement  [PDF]
Forkapi? S.,Bikit I.,?onki? Lj,Veskovi? M.
Facta Universitatis Series : Physics, Chemistry and Technology , 2006, DOI: 10.2298/fupct0601001f
Abstract: Several important international scientific organizations have designated radon as a carcinogenic and serious health problem. As a chemically inert gas, it is easily released from soil, building materials, and water, to emanate to the atmosphere. Since 1992, Laboratory for Nuclear Physics of the Department of Physics, Faculty of Sciences in Novi Sad has been involved in measurements of radon concentration in air, using several different techniques. Last year, systematic radon measurements in drinking waters began, too. The work presented here gives a survey and discussion of the results of the both series of measurements.
Characterization of a Novel Interaction between Bcl-2 Members Diva and Harakiri  [PDF]
Lorenzo Sborgi,Susana Barrera-Vilarmau,Patricia Obregón,Eva de Alba
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0015575
Abstract: Interactions within proteins of the Bcl-2 family are key in the regulation of apoptosis. The death-inducing members control apoptotic mechanisms partly by antagonizing the prosurvival proteins through heterodimer formation. Structural and biophysical studies on these complexes are providing important clues to understand their function. To help improve our knowledge on protein-protein interactions within the Bcl-2 family we have studied the binding between two of its members: mouse Diva and human Harakiri. Diva has been shown to perform both prosurvival and killing activity. In contrast, Harakiri induces cell death by interacting with antiapoptotic Bcl-2 members. Here we show using ELISA and NMR that Diva and Harakiri can interact in vitro. Combining the NMR data with the previously reported three-dimensional structure of Diva we find that Harakiri binds to a specific region in Diva. This interacting surface is equivalent to the known binding area of prosurvival Bcl-2 members from the reported structures of the complexes, suggesting that Diva could function at the structural level similarly to the antiapoptotic proteins of the Bcl-2 family. We illustrate this result by building a structural model of the heterodimer using molecular docking and the NMR data as restraints. Moreover, combining circular dichroism and NMR we also show that Harakiri is largely unstructured with residual (13%) α-helical conformation. This result agrees with intrinsic disorder previously observed in other Bcl-2 members. In addition, Harakiri constructs of different length were studied to identify the region critical for the interaction. Differential affinity for Diva of these constructs suggests that the amino acid sequence flanking the interacting region could play an important role in binding.
Automated Determination of Stellar Parameters from Simulated Dispersed Images for DIVA  [PDF]
P. G. Willemsen,C. A. L. Bailer-Jones,T. A. Kaempf,K. S. deBoer
Physics , 2003, DOI: 10.1051/0004-6361:20030195
Abstract: We have assessed how well stellar parameters (T_eff, logg and [Fe/H]) can be retrieved from low-resolution dispersed images to be obtained by the DIVA satellite. Although DIVA is primarily an all-sky astrometric mission, it will also obtain spectrophotometric information for about 13 million stars (operational limiting magnitude V ~ 13.5 mag). Constructional studies foresee a grating system yielding a dispersion of ~200nm/mm on the focal plane (first spectral order). For astrometric reasons there will be no cross dispersion which results in the overlapping of the first to third diffraction orders. The one-dimensional, position related intensity function is called a DISPI (DISPersed Intensity). We simulated DISPIS from synthetic spectra (...) for a limited range of metallicites i.e. our results are for [Fe/H] in the range -0.3 to 1 dex. We show that there is no need to deconvolve these low resolution signals in order to obtain basic stellar parameters. Using neural network methods and by including simulated data of DIVA's UV telescope, we can determine T_eff to an average accuracy of about 2% for DISPIS from stars with 2000 K < T_eff < 20000 K and visual magnitudes of V=13 mag (end of mission data). logg can be determined for all temperatures with an accuracy better than 0.25 dex for magnitudes brighter than V=12 mag. For low temperature stars with 2000 K < T_eff < 5000 K and for metallicities in the range -0.3 to +1 dex a determination of [Fe/H] is possible (to better than 0.2 dex) for these magnitudes. Additionally we examined the effects of extinction E(B-V) on DISPIS and found that it can be determined to better than 0.07 mag for magnitudes brighter than V=14 mag if the UV information is included.
Effects of bedrock type on the indoor radon concentrations at the office buildings in Gyeongju, Korea  [PDF]
Park Hee Chan,Jang Young So,Kim Jae Shin,Moon Hyun Joo
Nuclear Technology and Radiation Protection , 2011, DOI: 10.2298/ntrp1103226p
Abstract: This study measured the indoor radon concentrations at 23 administrative office buildings in Gyeongju, Korea, which consists of 23 administrative districts. Using the Korean geological information system, the type of bedrock under the administrative office buildings was identified and classified in 3 major types: granite, sedimentary rock, and sedimentary rock-based fault. The changes in the indoor concentrations at the 23 administrative office buildings were analyzed according to the type of bedrock. As a result, the radon concentration in the areas with the granite bedrock was generally higher than that in the region of two other types of bedrock. In addition, the radon concentration was evaluated according to surface area and construction timing of the building. The indoor radon concentration generally increased with decreasing surface area of the building, particularly in granite distributed areas. For a building aged more than 15 years, the radon concentration in the building in the granite area was much higher. For the building aged 1 or 2 years, the radon concentration was high regardless of the type of the bedrock due to radon emanation from the building material, such as concrete.
Permeability as an important parameter for radon risk classification of foundation soils  [cached]
M. Neznal,M. Neznal
Annals of Geophysics , 2005, DOI: 10.4401/ag-3192
Abstract: Permeability of soils and rocks for gases is one of the main parameters for final radon risk classification of building sites. For the improvement of the method for radon risk classification it is recommended to complete in situ measurements of permeability and/or results derived from grain size analysis by an expert description of parameters of soils and rocks and their changes in vertical profile.
Radon in Caves.
Cigna Arrigo A.
International Journal of Speleology , 2005,
Abstract: The physical characteristics of radon are reported as well as its sources,the transport in rock and its behaviour in caves. Then,the instruments,both active and passive, used for the measurement of radon concentration are discussed by taking into accounttheir respective advantages and disadvantages for the use in the cave environment. Since in many countries radon is the objectof regulations that were adopted for radiation protection purposes, this aspect is examined and the recommendations issued byinternational organisations and enforced in different countries are reported. Materials, methods and other remarks on the limitsimplementation are also listed with the aim of providing the managers of show caves with some instruments to comply with thedomestic requirements with the most convenient solution.
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.