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Sample records for 222rn concentration dwelling

  1. Activity concentrations of 222Rn, 220Rn, and their decay products in german dwellings, dose calculations and estimate of risk.

    PubMed

    Keller, G; Folkerts, K H; Muth, H

    1982-01-01

    Measurements of the concentrations of 222Rn, its short-lived decay products and of 212Pb - 212Bi were performed in 150 dwellings and in the open air in the Federal Republic of Germany. The concentrations of 222Rn was measured by electrostatic deposition of 218Po. The concentration of the short-lived decay products were measured by air sampling and alpha-spectroscopy. It was found that inside dwellings the average potential alpha-energy concentration of the short-lived daughters is about three times higher than in the open air. The total potential alpha-energy concentration indoors amounts to 2.6 . 10(-3) Working Level (W.L.). Direct measurements of the equilibrium factor inside dwellings gave a mean value of 0.3. A strong dependence of the potential alpha energy concentration on the ventilation rate in dwellings has been observed. These ventilation effects exceed the effects caused by differences in the activity concentrations due to different building materials. The dose calculation results in an average dose to the whole lung due to the inhalation of short-lived radon daughters of about 0.05-0.2 m/Gy/a. An estimate of risk - based on the risk factors for uranium miners - shows an average lifetime risk of about 6 . 10(-4) for the incidence of lung cancer caused by inhalation of radon and thoron daughters in dwellings in the Federal Republic of Germany. PMID:7146318

  2. Study of {sup 222}Rn concentrations in some dwellings of Rajasthan

    SciTech Connect

    Singh, A.K.; Prasad, R.; Khan, A.J.

    1999-03-01

    Total potential alpha energy concentrations due to radon progeny were measured in 143 dwellings of Udaipur, Bikaner, and Barnswara towns of Rajasthan province of India with LR-115 type II detectors. The geometric mean values of total potential alpha energy concentrations in these three towns were found to be 1.9 {times} 10{sup {minus}7} J m{sup {minus}3}, 1.2 {times} 10{sup {minus}7} J m{sup {minus}3} and 1.7 {times} 10{sup {minus}7} J m{sup {minus}3} with a geometric standard deviation of 2.2, 2.2, and 2.5, respectively. The estimated lifetime risk of lung cancer due to indoor radon exposure for a total population of study area was estimated to be 6.7 {times} 10{sup {minus}3} or 0.67%. The mean relative loss of life expectancies were 0.20%, 0.12%, and 0.18%, respectively.

  3. Determination of waterborne {sup 222}Rn concentrations using AC canisters

    SciTech Connect

    Mancini, C.; Giannelli, G.

    1995-09-01

    A method for measuring {sup 222}Rn concentration in water using charcoal canisters is presented. {sup 222}Rn is transferred within a few minutes from water contained in a 0.720 L bottle to a charcoal canister using a portable degassing unit. In the laboratory, gamma counting is performed at least 10 h after sampling to determine waterborne {sup 222}Rn concentration. The results obtained with charcoal canisters are compared to measurements made with Marinelli beakers calibrated in a comparison with liquid scintillation counting. The efficiency of transferring dissolved {sup 222}Rn in water to activated charcoal is 99% based on measurements made using Marinelli beakers. The lower limit of detection at the 95% confidence level is approximately 1 kBq m{sup -3} for a 15 min gamma count. the system was used to measure radon concentration in mineral groundwater near Rome. 7 refs., 1 fig., 1 tab.

  4. Radon ((222)Rn) concentration in indoor air near the coal mining area of Nui Beo, North of Vietnam.

    PubMed

    Nhan, Dang Duc; Fernando, Carvalho P; Thu Ha, Nguyen Thi; Long, Nguyen Quang; Thuan, Dao Dinh; Fonseca, Heloisa

    2012-08-01

    Concentrations of radioactive radon gas ((222)Rn) were measured using passive monitors based on LR115 solid state track detectors during June-July 2010 in indoor air of dwellings in the Nui Beo coal mining area, mostly in Cam Pha and Ha Long coastal towns, Quang Ninh province, in the North of Vietnam. Global results of (222)Rn concentrations indoors varied from ≤6 to 145 Bq m(-3) averaging 46 ± 26 Bq m(-3) (n = 37), with a median value of 47 Bq m(-3). This was similar to outdoor (222)Rn concentrations in the region, averaging 43 ± 19 Bq m(-3) (n = 10), with a median value of 44 Bq m(-3). Indoor (222)Rn concentrations in the coastal town dwellings only were in average lower although not significantly different from indoor (222)Rn concentrations measured at the coal storage field near the harbor, 67 ± 4 Bq m(-3) (n = 3). Furthermore, there was no significant difference in the average (222)Rn concentration in indoor air measured in the coastal towns region and those at the touristic Tuan Chau Island located about 45 km south of the coal mine, in the Ha Long Bay. The indoor (222)Rn concentration in a floating house at the Bai Tu Long Bay, and assumed as the best estimate of the baseline (222)Rn in surface air, was 27 ± 3 Bq m(-3) (n = 3). Indoor average concentration of (222)Rn in dwellings at the Ha Noi city, inland and outside the coal mining area, was determined at 30 Bq m(-3). These results suggest that (222)Rn exhalation from the ground at the Nui Beo coal mining area may have contributed to generally increase (222)Rn concentration in the surface air of that region up to 1.7 times above the baseline value measured at the Bai Tu Long Bay and Ha Noi. The average indoor concentration of (222)Rn in Cam Pha-Ha Long area is about one-third of the value of the so-called Action Level set up by the US EPA of 148 Bq m(-3). Results suggest that there is no significant public health risk from (222)Rn exposure in the study region. PMID

  5. Measurements of indoor 222RN activity in dwellings and workplaces of Curitiba (Brazil)

    NASA Astrophysics Data System (ADS)

    Corrêa, Janine N.; Paschuk, Sergei A.; Del Claro, Flávia; Kappke, Jaqueline; Perna, Allan F. N.; Schelin, Hugo R.; Denyak, Valeriy

    2014-11-01

    The present work describes the results of systematic measurements of radon (222Rn) in residential environments and workplaces in the Metropolitan Region of Curitiba (Paraná State, Brazil) during the period 2004-2012. For radon in air activity measurements, polycarbonate Track Etch Detectors CR-39, mounted in diffusion chambers protected by borosilicate glass fiber filters, were used. After being exposed in air, the CR-39 detectors were submitted to a chemical etching in a 6.25 M NaOH solution at 70 °C for 14 h. The alpha particle tracks were identified and manually counted with an optical microscope, and with the results of previously performed calibrations, the indoor activity concentration of 222Rn was calculated. The calibration of CR-39 and the alpha particle tracks chemical development procedures were performed in collaboration the National Institute of Radiological Sciences (NIRS, Japan). The major part of indoor 222Rn concentration in residences was found to be below 100 Bq/m3. In the case of working places, all measurements of 222Rn concentrations were below 100 Bq/m3. These values are considered within the limits set by international regulatory agencies, such as the US EPA and ICRP, which adopt up to 148 and 300 Bq/m3 as upper values for the reference levels for radon gas activity in dwellings, respectively. The latest value of 300 Bq/m3 for radon activity in air is proposed by ICRP considering the upper value for the individual dose reference level for radon exposure of 10 mSv/yr.

  6. Attached, unattached fraction of progeny concentrations and equilibrium factor for dose assessments from (222)Rn and (220)Rn.

    PubMed

    Singh, Parminder; Saini, Komal; Mishra, Rosaline; Sahoo, Bijay Kumar; Bajwa, Bikramjit Singh

    2016-08-01

    In this study, measurements of indoor radon ((222)Rn), thoron ((220)Rn) and their equilibrium equivalent concentration (EEC) were carried out in 96 dwellings from 22 different villages situated in Hamirpur district, Himachal Pradesh, India, by using LR-115 type II-based pinhole twin cup dosimeters and deposition-based progeny sensors (DRPS/DTPS). The annual average indoor (222)Rn and (220)Rn concentrations observed in these dwellings were 63.82 and 89.59 Bq/m(3), respectively, while the average EEC (attached + unattached) for (222)Rn and (220)Rn was 29.28 and 2.74 Bq/m(3). For (222)Rn (f Rn) and (220)Rn (f Tn), the average values of unattached fraction were 0.11 and 0.09, respectively. The equilibrium factors for radon (F Rn) and thoron (F Tn) varied from 0.12 to 0.77 with an average of 0.50, and from 0.01 to 0.34 with an average of 0.05, respectively. The annual inhalation dose due to mouth and nasal breathing was calculated using dose conversion factors and unattached fractions. The indoor annual effective doses for (222)Rn (AEDR) and (220)Rn (AEDT) were found to be 1.92 and 0.83 mSv a(-1), respectively. The values of (222)Rn/(220)Rn concentrations and annual effective doses obtained in the present study are within the safe limits as recommended by the International Commission on Radiological Protection for indoor dwelling exposure conditions. PMID:27289385

  7. Measurement of 222Rn flux, 222Rn emanation, and 226,228Ra concentration from injection well pipe scale.

    PubMed

    Rood, A S; White, G J; Kendrick, D T

    1998-08-01

    222Rn flux (Bq s(-1)) was measured from the ends of twenty sections of produced water injection tubing (pipe) containing barite scale contaminated with naturally occurring radioactive material. Exposure measurements near the pipes were as high as 77.4 nC kg(-1)h(-1) (300 microR h(-1)). Flux measurements were accomplished by first purging the pipes with dry nitrogen and then collecting the outflow (nitrogen and radon) on charcoal columns affixed to the end of the pipe for 66 hours. As determined in this manner, 222Rn flux from the ends of the pipe ranged from 0.017 to 0.10 Bq s(-1) (0.46 to 2.7 pCi s(-1)). Following the radon flux measurements, pipe scale was removed and a representative sample was taken for 226Ra and 228Ra concentration measurements and determination of 222Rn emanation fractions (the fraction of the total radon contained in a material that is released from the material and free to migrate). The samples were also analyzed for gross mineral content. Emanation fraction measurements for 222Rn ranged from 0.020 to 0.063, while 226Ra concentrations ranged from 15.7 to 102 Bq g(-1) (424 to 2,760 pCi g(-1)). Barite was the predominate mineral in 17 of the 20 scale samples collected. Much of the previous work dealing with radon emanation fraction measurements has involved uranium mill tailings. Compared to mill tailings and natural soils which have emanation fractions that typically range from 0.1 to 0.3, the emanation fractions measured for these NORM scales are substantially lower. PMID:9685074

  8. Laboratory scale studies on mitigation of high 222Rn concentrations in air and water

    NASA Astrophysics Data System (ADS)

    Mamoon, A.; Gomma, M. A.; Sohsah, M.

    2004-01-01

    In view of the occasional occurrence of high 222Rn concentrations in air and water under certain circumstances, and in view of the potential health hazards of increased levels of 222Rn in respirable air and in potable water, mitigation of such high 222Rn concentration has become of primary concern. To facilitate the study of the efficiency of the various 222Rn mitigating factors simple laboratory systems were used. Altered alkali granite was used as radon source to enrich air and a piece of pitchblende was used as radon source to enrich water samples. Both enriched media will then be subjected to the mitigation treatments. Charcoal canister technique along with gamma spectrometry were used to measure 222Rn concentrations in air before and after the different mitigating treatments. These were: use of ventilation, radon barriers such as geo-membranes and aluminum sheet, and sealant such as epoxy and vinyl tape. Regarding high levels of 222Rn in air ventilation was the most efficient mitigating factor. Standard liquid scintillation counting was used to measure 222Rn concentrations in water before and after the different mitigation treatments. These were: use of aeration, activated charcoal and heating. Regarding high levels of 222Rn in water, aeration using bubblers and large volume of air was most effective in removing radon from water in a short time. However all the mitigating factors proved effective, in different degrees in decreasing 222Rn concentrations in the respective media. The result from these studies are in general agreement with reports in the literature. It can be concluded then that the different 222Rn mitigating factors can be tested and compared effectively under controlled conditions using simple laboratory scale systems.

  9. Distribution of 222Rn concentration in an inhabited area adjacent to the Aja granitic heights of Hail Province, Saudi Arabia.

    PubMed

    Kinsara, Abdulraheem Abdulrahman; Shabana, El-Said Ibrahim; Abulfaraj, Waleed Hussain; Qutub, Maher Mohammad Taher

    2015-01-01

    Radon-222 has been measured in groundwater, dwellings, and atmosphere of an inhabited area adjacent to the granitic Aja heights of Hail province, Saudi Arabia. The measurements were carried out in the field using a RAD7 instrument. Twenty-eight water samples, collected from drilled wells scattered in the region, were analyzed. Radon-222 concentration ranged from 2.5-95 kBq m(-3) with an average value of about 30.3 kBq m(-3). The higher values were found in wells drawing water from granitic aquifers. Indoor 222Rn was measured in 20 dwellings of rural areas in Hail city and other towns. Concentrations ranged from 12-125.6 Bq m(-3), with an average value of 54.6 Bq m(-3). Outdoor air 222Rn was measured at 16 sites, with values ranging from 6.2-13.3 Bq m(-3), with an average value of 10.5 Bq m(-3). The estimated average effective dose due to inhalation of 222Rn released from water was 0.08 mSv y(-1). The estimated average annual effective dose due to indoor 222Rn was 1.35 mSv, which lies below the effective dose range (3-10 mSv) given as the recommended action level. Based on the average dose rate values, the excess lifetime cancer risk values were estimated as 69.8 × 10(-4) due to indoor radon and 13.4 × 10(-4) due to outdoor radon. PMID:25437521

  10. Development and calibration of a portable radon sampling system for groundwater 222Rn activity concentration measurements.

    PubMed

    Lucas, Fabio de Oliveira; de Oliveira, Igor José Chaves; Ribeiro, Fernando Brenha

    2009-10-01

    The assembling of a system for field sampling and activity concentration measurement of radon dissolved in groundwater is described. Special attention is given in presenting the calibration procedure to obtain the radon activity concentration in groundwater from the raw counting rate registered in a portable scintillation detector and in establishing the precision of the activity concentration measurements. A field procedure was established and the system tested during one year of monthly observations of (222)Rn activity concentration in groundwater drawn from two wells drilled on metamorphic rocks exposed at Eastern São Paulo State, Brazil. The observed mean (222)Rn activity concentrations are 374Bq/dm(3) in one well and about 1275Bq/dm(3) in the other one. In both wells the (222)Rn activity concentrations showed a seasonal variation similar to variations previously reported in the literature for the same region. PMID:19608307

  11. Measurement of {sup 222}Rn flux, {sup 222}Rn emanation and {sup 226}Ra concentration from injection well pipe scale

    SciTech Connect

    Rood, A.S.; Kendrick, D.T.

    1996-02-01

    The presence of Naturally Occurring Radioactive Material (NORM) has been recognized since the early 1930s in petroleum reservoirs and in oil and gas production and processing facilities. NORM was typically observed in barite scale that accumulated on the interior of oil production tubing and in storage tank and heater-treater separation sludge. Recent concern has been expressed over the health impacts from the uncontrolled release of NORM to the public. There are several potential exposure pathways to humans from oil-field NORM. Among these is inhalation of radon gas and its daughter products. For this exposure pathway to be of any significance, radon must first be released from the NORM matrix and diffuse in free air. The radon emanation fraction refers to the fraction of radon atoms produced by the decay of radium, that migrate from the bulk material as free gaseous atoms. The purpose of this investigation was to characterize the radon release rates from NORM-scale contaminated production tubing being stored above ground, characterize the radon emanation fraction of the bulk scale material when removed from the tubing, and characterize the radium concentrations of the scale. Accurate characterization of {sup 222}Rn emanation fractions from pipe scale may dictate the type of disposal options available for this waste. Characterization of radon release from stored pipes will assist in determining if controls are needed for workers or members of the public downwind from the source. Due to the sensitive nature of this data, the location of this facility is not disclosed.

  12. Equilibration correction of temporal measurements for sudden 222Rn concentration changes

    NASA Astrophysics Data System (ADS)

    Tan, Y.; Tokonami, S.; Liu, H.; Kearfott, K. J.

    2016-02-01

    222Rn and 220Rn can be used as tracers of groundwater or submarine springs, and 222Rn in water also could indicate indoor radon problems in some regions. The half-life of 222Rn is long enough that its concentration may remain significant during transit over relatively long distances, while that of 220Rn is not. Prior research revealed that it took about 15 min for the radon to achieve gas equilibrium at a water flow rate of 17.5 L min-1, which is approximately equivalent to the time required for the 222Rn-218Po pair to approach radioactive equilibrium and is limiting in terms of measurements of sudden radon concentration change. In this work, an algorithm is applied to improve the continuous tracing of radon concentrations in the field environment. Results of a laboratory experiment analyzed applying the analysis method illustrated its ability to allow immediate identification of sharp concentration increases. In this paper we find that a precipitous drop in radon concentrations lead to improper corrected values as the result of measurement uncertainties prior to the drop, and a method using zero instead negative values for reducing the uncertainties under such condition also is proposed.

  13. Measurements of 222Rn activity concentration in domestic water sources in Penang, northern peninsular Malaysia.

    PubMed

    Muhammad, B G; Jaafar, M S; Azhar, A R; Akpa, T C

    2012-04-01

    Measurements of (222)Rn activity concentration were carried out in 39 samples collected from the domestic and drinking water sources used in the island and mainland of Penang, northern peninsular, Malaysia. The measured activity concentrations ranged from 7.49 to 26.25 Bq l(-1), 0.49 to 9.72 Bq l(-1) and 0.58 to 2.54 Bq l(-1) in the raw, treated and bottled water samples collected, respectively. This indicated relatively high radon concentrations compared with that from other parts of the world, which still falls below the WHO recommended treatment level of 100 Bq l(-1). From this data, the age-dependent associated committed effective doses due to the ingestion of (222)Rn as a consequence of direct consumption of drinking water were calculated. The committed effective doses from (222)Rn resulting from 1 y's consumption of these water were estimated to range from 0.003 to 0.048, 0.001 to 0.018 and 0.002 to 0.023 mSv y(-1), for age groups 0-1, 2-16 and >16 y, respectively. PMID:21642647

  14. Experimental studies about the ratio between 210Po deposited on surfaces and retrospective indoor 222Rn concentrations.

    PubMed

    Martín Sánchez, A; de la Torre Pérez, J; Ruano Sánchez, A B

    2014-07-01

    Measurements of radon concentration may not be sufficiently representative for the cumulative total exposure suffered by a person throughout his life. Retrospective dosimetry can help estimating from the direct measurement of 210Po (descendant of 222Rn) implanted on surfaces, because this quantity is related (through the conversion factor) with the mean indoor 222Rn concentration existing in a room for long time. This factor depends on multiple variables. Theoretical models can provide some values. Experiments are tedious and very time consuming. The 210Po activity concentration was measured in mirrors, which were previously exposed to 222Rn concentrations under real environmental conditions. This work deals with the preliminary results in two known places (a room and a cave), which have very different characteristics, in order to show experimentally the large differences found in the values of this factor. PMID:24729559

  15. Concentrations of 222Rn, Its Short-Lived Daughters And 212Pb And Their Ratios Under Complex Atmospheric Conditions And Topography

    NASA Astrophysics Data System (ADS)

    Kataoka, Toshio; Yunoki, Eiji; Shimizu, Mitsuo; Mori, Tadashige; Tsukamoto, Osamu; Takahashi, Satoshi; Fudeyasu, Hironori; Ohashi, Yukitaka; Sahashi, Ken; Maitani, Toshihiko; Miyashita, Koh'ichi; Iwata, Toru; Sasaki, Takayuki; Fujikawa, Yoko; Kudo, Akira; Shaw, Roger H.

    Atmospheric activity concentrations of 212Pb and short-lived 222Rndaughters, together with meteorological elements, have been observed continuously atthree sites at Kamisaibara Village in Japan. In addition, atmospheric activity concentrationof 222Rn, equilibrium-equivalent concentration of 222Rn and conditionsof the lower atmosphere were observed for three intensive observation periods at Akawase,one of the three sites in Kamisaibara Village. The equilibrium-equivalent concentration of222Rn is almost the same as the atmospheric activity concentration of short-lived222Rn daughters.The activity concentrations of 212Pb and the short-lived 222Rn daughtersand their ratio were low in the daytime owing to convective mixing, and high at nightowing to the surface-based inversion during periods of no precipitation. Their variationshave several patterns corresponding to the scale of the drainage wind or weak mixing.

  16. Short-term 222Rn activity concentration changes in underground spaces with limited air exchange with the atmosphere

    NASA Astrophysics Data System (ADS)

    Fijałkowska-Lichwa, L.; Przylibski, T. A.

    2011-04-01

    The authors investigated short-time changes in 222Rn activity concentration occurring yearly in two underground tourist facilities with limited air exchange with the atmosphere. One of them is Niedźwiedzia (Bear) Cave in Kletno, Poland - a natural space equipped with locks ensuring isolation from the atmosphere. The other site is Fluorite Adit in Kletno, a section of a disused uranium mine. This adit is equipped with a mechanical ventilation system, operated periodically outside the opening times (at night). Both sites are situated within the same metamorphic rock complex, at similar altitudes, about 2 km apart. The measurements conducted revealed spring and autumn occurrence of convective air movements. In Bear Cave, this process causes a reduction in 222Rn activity concentration in the daytime, i.e. when tourists, guides and other staff are present in the cave. From the point of view of radiation protection, this is the best situation. For the rest of the year, daily concentrations of 222Rn activity in the cave are very stable. In Fluorite Adit, on the other hand, significant variations in daily 222Rn activity concentrations are recorded almost all year round. These changes are determined by the periods of activity and inactivity of mechanical ventilation. Unfortunately this is inactive in the daytime, which results in the highest values of 222Rn activity concentration at the times when tourists and staff are present in the adit. Slightly lower concentrations of radon in Fluorite Adit are recorded in the winter season, when convective air movements carry a substantial amount of radon out into the atmosphere. The incorrect usage of mechanical ventilation in Fluorite Adit results in the most unfavourable conditions in terms of radiation protection. The staff working in that facility are exposed practically throughout the year to the highest 222Rn activity concentrations, both at work (in the adit) and at home (outside their working hours). Therefore, not very well

  17. Year-to-year variations in annual average indoor 222Rn concentrations.

    PubMed

    Martz, D E; Rood, A S; George, J L; Pearson, M D; Langner, G H

    1991-09-01

    Annual average indoor 222Rn concentrations in 40 residences in and around Grand Junction, CO, have been measured repeatedly since 1984 using commercial alpha-track monitors (ATM) deployed for successive 12-mo time periods. Data obtained provide a quantitative measure of the year-to-year variations in the annual average Rn concentrations in these structures over this 6-y period. A mean coefficient of variation of 25% was observed for the year-to-year variability of the measurements at 25 sampling stations for which complete data were available. Individual coefficients of variation at the various stations ranged from a low of 7.7% to a high of 51%. The observed mean coefficient of variation includes contributions due to the variability in detector response as well as the true year-to-year variation in the annual average Rn concentrations. Factoring out the contributions from the measured variability in the response of the detectors used, the actual year-to-year variability of the annual average Rn concentrations was approximately 22%. PMID:1880029

  18. Outdoor (222)Rn-concentrations in Germany - part 2 - former mining areas.

    PubMed

    Kümmel, M; Dushe, C; Müller, S; Gehrcke, K

    2014-06-01

    In the German Federal States of Saxony, Saxony-Anhalt and Thuringia, centuries of mining and milling activities resulted in numerous residues with increased levels of natural radioactivity such as waste rock dumps and tailings ponds. These may have altered potential radiation exposures of the population significantly. Especially waste rock dumps from old mining activities as well as 20th century uranium mining may, due to their radon ((222)Rn) exhalation capacity, lead to significant radiation exposures. They often lie close to or within residential areas. In order to study the impact on the natural radon level, the Federal Office for Radiation Protection (BfS) has run networks of radon measurement points in 16 former mining areas, together with 2 networks in regions not influenced by mining for comparison purposes. Representative overviews of the long-term outdoor radon concentrations could be established including estimates of regional background concentrations. Former mining and milling activities did not result in large-area impacts on the outdoor radon level. However, significantly increased radon concentrations were observed in close vicinity of shafts and large waste rock dumps. They are partly located in residential areas and need to be considered under radiation protection aspects. Examples are given that illustrate the consequences of the Wismut Ltd. Company's reclamation activities on the radon situation. PMID:24508448

  19. The role of mesoscale meteorology in modulating the (222)Rn concentrations in Huelva (Spain)--impact of phosphogypsum piles.

    PubMed

    Hernández-Ceballos, M A; Vargas, A; Arnold, D; Bolívar, J P

    2015-07-01

    The combined analysis of (222)Rn activity concentrations and mesoscale meteorological conditions at Huelva city (Spain) was addressed in this study to understand the potential impact of phosphogypsum piles on the (222)Rn activity concentrations registered at this area. Hourly mean data from April 2012 to February 2013 registered at two sampling sites (Huelva city and in the background station of El Arenosillo, located 27 km to the south-east) have been used in the study. The results of the present study showed a large difference in mean radon concentrations between the two stations during the sampling period, 6.3 ± 0.4 Bq m(-3) at Huelva and 3.0 ± 0.2 Bq m(-3) at El Arenosillo. The analysis has demonstrated that hourly (222)Rn concentrations at Huelva city above 22 Bq m(-3), with nocturnal peaks up to 50 Bq/m(3), mainly coincided with the occurrence of a pure sea-land breeze cycle. Mesoscale circulations in this region are mainly characterized by two patterns of sea-land breeze, pure and non-pure, with the phosphosypsum piles directly upstream (south) of the city during the afternoon on pure sea-breeze days. The difference between mean (222)Rn activity concentrations at Huelva city were 9.9 ± 1.5 Bq m(-3) for the pure pattern and 3.3 ± 0.5 Bq m(-3) for the non-pure pattern, while in the background station concentrations were 3.9 ± 0.4 Bq m(-3) and 2.8 ± 0.4 Bq m(-3) respectively. Considering these large differences, a detailed analysis of composites and case studies of representative sea-land breeze cycles of both types and their impact on (222)Rn activity concentration was performed. The results suggested that the presence of the phosphogypsum piles was necessary in order to justify the high (222)Rn activity concentrations observed at Huelva compared with the background station in the afternoons on pure sea breeze days (1.5-2.0 Bq m(-3)). On the other hand, large night time differences between the two sites on these days were

  20. Mean annual (222)Rn concentration in homes located in different geological regions of Poland: first approach to whole country area.

    PubMed

    Przylibski, Tadeusz A; Zebrowski, Adam; Karpińska, Maria; Kapała, Jacek; Kozak, Krzysztof; Mazur, Jadwiga; Grządziel, Dominik; Mamont-Cieśla, Kalina; Stawarz, Olga; Kozłowska, Beata; Kłos, Barbara; Dorda, Jerzy; Wysocka, Małgorzata; Olszewski, Jerzy; Dohojda, Marek

    2011-08-01

    The paper presents the results of year-long measurements of radon ((222)Rn) concentration inside 129 buildings in Poland in relation to the geological conditions of their foundation. The authors took into account the division of the country into tectonic units, as well as the lithology of the rocks forming the bedrock of these buildings. As expected, the highest value of mean annual (222)Rn concentration (845 Bq/m(3)) was recorded in a building situated in the area of the Sudetes, while the highest geometric mean (characteristic of the expected log-normal data distribution) was calculated based on measurements from buildings located within the East-European craton, in the area of Mazury-Podlasie monocline, where it reached 231 Bq/m(3). Such results reflect geological conditions - the occurrence of crystalline rocks (especially U- and Ra-enriched granites and orthogneisses) on the surface in the Sudetes, and of young post-glacial sediments containing fragments of Scandinavian crystalline rocks, also enriched with U and Ra, in the area of Mazury-Podlasie monocline. However, the least expected result of the investigations was finding out that, contrary to the hitherto widespread belief, none of the major tectonic units of Poland can be excluded from the list of those containing buildings with mean annual (222)Rn concentration exceeding 200 Bq/m(3). The mean annual concentration of radon for all the buildings were much higher than the mean concentration value (49.1 Bq/m(3)) of indoor radon in Poland quoted so far. These results cast a completely new light on the necessity to perform measurements of radon concentration in residential buildings in Poland, no more with reference to small areas with outcrops of crystalline rocks (especially the Sudetes, being the Polish fragment of the European Variscan belt), but for all the major tectonic units within Poland. PMID:21555169

  1. Radon-222 concentrations and decay-product equilibrium in dwellings and in the open air.

    PubMed

    Keller, G; Folkerts, K H

    1984-09-01

    Results are presented of measurements of the activity concentrations of 222Rn and its short-lived decay products and the 212Pb/212Bi concentrations in more than 200 dwellings in West Germany and in the open air. For more than 130 measurements of the equilibrium factor F in dwellings the median value was found to be 0.3. Measurements of F in the open air under various conditions resulted in a mean value of about 0.4. The results of the investigations showed that indoors F depends only slightly on ventilation, indoor 222Rn concentration and other parameters. The equilibrium factor F in the open air, however, was found to depend on meteorological conditions. Empirical correlations from the data obtained for the daughter/222Rn concentration ratios were derived to provide relations for the prediction of the individual daughter product concentrations at a measured 222Rn level. It was established that the daughter/222Rn concentration ratios for indoor air do not change within the range of 222Rn concentrations investigated (1-370 Bq X m-3). These relations, however, are not valid for the daughter/222Rn concentration ratios in outdoor air. The correlations derived further suggest that the individual daughter product concentrations may be assessed with sufficient accuracy by only measuring the 222Rn concentrations. Thus the daughter ratios obtained in this way should enable good estimates of the lung dose for members of the public due to inhalation of the short-lived 222Rn daughters and the dose contribution of the individual 222Rn-daughter products. PMID:6094394

  2. Survey of [sup 222]Rn concentrations in the air of a tunnel located in Nagano City using the solid-state nuclear track detector method

    SciTech Connect

    Muramatsu, H.; Hasegawa, N.; Misawa, C.; Minami, M.; Tanaka, E.; Asami, K.; Kuroda, C.; Kawakami, A. . Dept. of Chemistry)

    1999-07-01

    The survey of [sup 222]Rn concentration in the air of tunnels constructed during World War II has been performed using a solid-state nuclear track detector technique. For the practical application of this technique t the determination of [sup 222]Rn concentrations in air, some basic properties were experimentally examined on the cellulose nitrate film, Kodak LR 115 type II. The calibration coefficient of the cellulose nitrate film used is determined from a correlation between the [sup 222]Rn concentration in air and the observed number of perforated etched tracks for widespread radon concentrations. The slope of the linear relationship observed yields a calibration coefficient of (0.00209 [+-] 0.00018) tracks cm[sup [minus]2] (Bq m[sup [minus]3] h)[sup [minus]1]. From the survey of [sup 222]Rn concentration in the air of tunnels, the concentration of several thousand Bq m[sup [minus]3] was observed at the inner most area of the tunnel, and the seasonal variation was clearly observed. The exponential distribution of radon concentration as a function of distance from the openings of the tunnel suggests that the radon concentration in the tunnel is basically governed by diffusion and mixing of radon gas with air.

  3. Errors in measurements of 222Rn in methane and carbon dioxide using scintillation cells calibrated for 222Rn in air.

    PubMed

    Jenkins, Phillip H; Burkhart, James F; Camley, Robert E

    2014-03-01

    Scintillation cells are used typically for measuring the concentration of (222)Rn in air and are calibrated for that purpose. However, scintillation cells are sometimes used for measuring (222)Rn in natural gas or carbon dioxide. The counting efficiencies of scintillation cells for measurements of (222)Rn in these gases should be different from those for measuring (222)Rn in air because the ranges of alpha particles emitted by (222)Rn and its progeny are greater in methane and smaller in carbon dioxide than in air. If these effects are not taken into consideration, measurements of (222)Rn in natural gas will be biased high and in carbon dioxide will be biased low. The authors previously investigated the effects of barometric pressure on measurements of (222)Rn in air using scintillation cells. A modeling technique was used in a previous study to calculate theoretical errors that would result if atmospheric pressure were not considered. In the current study, the same modeling technique was used to calculate theoretical errors that would be made for measurements of (222)Rn in methane and carbon dioxide if the calibration for (222)Rn in air were used. Results are presented for four types of scintillation cells of varying geometries and for barometric pressures representative of four elevations ranging from sea level to 1,963 m (6,440 feet). These results indicate that the errors introduced by the ranges of the alpha particles in gases different from air can be significant. Depending on the type of cell and the local pressure, a measurement of (222)Rn in methane may be biased high by 2-7%, while a measurement of (222)Rn in CO2 may be biased low by 15-20% if the calibration for (222)Rn in air is used. PMID:25208015

  4. Estimation of Hg 0 exchange between ecosystems and the atmosphere using 222Rn and Hg 0 concentration changes in the stable nocturnal boundary layer

    NASA Astrophysics Data System (ADS)

    Obrist, Daniel; Conen, Franz; Vogt, Roland; Siegwolf, Rolf; Alewell, Christine

    The goal of this study was to test a 222Rn/Hg 0 method to measure exchange fluxes of Hg 0 between ecosystems and the atmosphere complementing gradient-based micrometeorological methods which are difficult to apply when exchange fluxes are very low, during calm nights, and over heterogeneous surfaces. The method is based on absolute concentration changes of Hg 0 and of the trace gas 222Rn over several hours in the stable nocturnal boundary layer (NBL) when absolute gas concentrations change according to the source or sink strength of the underlying landscape. 222Rn accumulations were observed in 28 of 66 measured nights in an urban area and in 14 of the 40 nights at a subalpine grassland. Concurrent and significant increases in atmospheric Hg 0 concentrations were observed 22 times in the urban area and calculated Hg 0 emissions—for the first time measured over a city area—averaged 6.4±0.9 ng m -2 h -1. Concurrent changes in Hg 0 in the stable NBLs at the subalpine site were very small and significant only nine times with calculated Hg 0 fluxes averaging -0.2±0.3 ng m -2 h -1, indicating that the flux of Hg 0 in the grassland was a very small net deposition of atmospheric Hg 0 to the ecosystem. At the subalpine grassland the 222Rn/Hg 0 method compared reasonably well to a modified Bowen ratio (MBR) method applied during turbulent conditions (-1.9±0.2 ng m -2 h -1 [or -1.7±0.4 ng m -2 h -1 during nights only]). The MBR, however, was not applicable in the urban area due to high surface roughness. We conclude that the 222Rn/Hg 0 method—although limited to nighttime periods in our study—can complement gradient-based methods during stable NBL periods and can be used over heterogeneous surfaces when conventional micrometeorological approaches are not applicable.

  5. Risk analysis of 222Rn gas received from East Anatolian Fault Zone in Turkey

    NASA Astrophysics Data System (ADS)

    Yilmaz, Mucahit; Kulahci, Fatih

    2016-06-01

    In this study, risk analysis and probability distribution methodologies are applied for 222Rn gas data received from Sürgü (Malatya) station located on East Anatolian Fault Zone (EAFZ). 222Rn data are recorded between 21.02.2007 and 06.06.2010 dates. For study are used total 1151 222Rn data. Changes in concentration of 222Rn are modeled as statistically.

  6. A solvent extraction technique for the measurement of 222Rn at ambient air concentrations.

    PubMed

    Prichard, H M

    1983-08-01

    The high solubility of radon in cold organic solvents is exploited to extract radon directly from a sample air stream into a hexane-based liquid scintillation solution. Up to 10 l. of air is passed through 20 ml of solvent held at -78 degrees C in a bath of dry ice and acetone. The solvent is then transferred to an ordinary glass liquid scintillation vial that has been preloaded with 2 ml of concentrated fluors. A large number of samples can be prepared in a short time with minimal equipment, making it possible for field workers to conveniently collect numerous samples prior to returning to the laboratory. After allowing an interval of at least 3 hr after processing for radon daughter ingrowth, the vials are counted on an unmodified liquid scintillation system with a narrow window set around the radon and polonium alpha peaks. The large sample volume more than compensates for the relatively high alpha background of liquid scintillators. Relevant theoretical considerations and alternate sampling strategies are discussed. PMID:6885455

  7. Development of an integrated sampler based on direct 222Rn/ 220Rn progeny sensors in flow-mode for estimating unattached/attached progeny concentration

    NASA Astrophysics Data System (ADS)

    Mishra, Rosaline; Sapra, B. K.; Mayya, Y. S.

    2009-11-01

    A flow-mode integrated sampler consisting of a wire-mesh and filter-paper array along with passive solid state nuclear track detectors has been developed for estimating unattached and attached fraction of 222Rn/ 220Rn progeny concentration. The essential element of this sampler is the direct 222Rn/ 220Rn progeny sensor (DRPS/DTPS), which is an absorber-mounted-LR115 type nuclear track detector that selectively registers the alpha particles emitted from the progeny deposited on its surface. During sampling at a specified flow-rate, the unattached progeny is captured on the wire-mesh; while the attached progeny gets transmitted and is captured on the filter-paper. The alpha particles emitted by the deposited progeny atoms are registered on the sensors placed at a specified distance facing the wire-mesh and the filter-paper, respectively. The various steps involved in the development of this flow-mode direct progeny sampler such as the optimization of the sampling rate and the distance between the sensor and the deposition substrate are discussed. The sensitivity factor of the DTPS-loaded sampler for 220Rn progeny deposited on the wire-mesh and filter-paper is found to be 23.77 ± 0.64 (track cm -2 h -1) (Bq m -3) -1 and 22.30 ± 0.18 (track cm -2 h -1) (Bq m -3) -1, respectively; while that of DRPS-loaded sampler for 222Rn progeny deposition, is 3.03 ± 0.14 (track cm -2 h -1) (Bq m -3) -1 and 2.08 ± 0.07 (track cm -2 h -1) (Bq m -3) -1, respectively. The highlight of this flow-mode sampler is its high sensitivity and that it utilizes the passive technique for estimating the unattached and attached progeny concentration, thus doing away with the alpha counting procedures.

  8. 222Rn variations in Mystery Cave, Minnesota

    USGS Publications Warehouse

    Lively, R.S.; Krafthefer, B.C.

    1995-01-01

    222Rn concentrations and meteorological parameters were measured at 4- h intervals over a 2-y period in Mystery Cave, southeastern Minnesota. Continuous radon monitors and meteorological sensors connected to data loggers were installed at several locations along commercial tour routes. 222Rn concentrations ranged as high as 25 kBq m-3 in summer and 20 kBq m-3 in winter. Average winter concentrations were lower than summer by at least a factor of two. Seasonal radon variations were correlative with outside air temperatures. During the winter, radon concentrations were observed to fluctuate periodically by factors of 20 or more in under 24 h. Both the long- and short-term variations are correlative with temperature- induced mixing of cave air with surface air.

  9. (222)Rn activity concentration differences in groundwaters of three Variscan granitoid massifs in the Sudetes (NE Bohemian Massif, SW Poland).

    PubMed

    Przylibski, Tadeusz A; Gorecka, Joanna

    2014-08-01

    Based on research conducted in three Variscan granitoid massifs located within the crystalline Bohemian Massif, the authors confirmed that the higher the degree of their erosional dissection, the smaller the concentration of (222)Rn in groundwaters circulating in these massifs. This notion implies that radon waters and high-radon waters, from which at least some of the dissolved radon should be removed before feeding them as drinking water to the water-supply system, could be expected in granitoid massifs which have been poorly exposed by erosion. At the same time, such massifs must be taken into account as the areas of possible occurrence of radon medicinal waters, which in some countries can be used for balneotherapy in health resorts. Slightly eroded granitoid massifs should be also regarded as very probable radon prone areas or areas of high radon potential. PMID:24657989

  10. Contribution of 222Rn in domestic water supplies to 222Rn in indoor air in Colorado homes

    USGS Publications Warehouse

    Lawrence, E.P.; Wanty, R.B.; Nyberg, P.

    1992-01-01

    The contribution of 222Rn from domestic water wells to indoor air was investigated in a study of 28 houses near Conifer, CO. Air concentrations determined by alpha-track detectors (ATDs) and continuous radon monitors were compared with the predictions of a single-cell model. In many of the houses, the water supply was shown to contribute significantly to levels of indoor 222Rn. The data from the ATD study were augmented with a continuous monitoring study of a house near Lyons, CO. The well water in that house has the highest known concentration of 222Rn in water yet reported (93 MBq m-3). The temporal pattern in the indoor 222Rn concentration corresponds to water-use records. In general, it is difficult to quantify the proportion of indoor radon attributable to water use. Several lines of evidence suggest that the single-cell model underestimates this proportion. Continuous- monitoring data, although useful, are impractical due to the cost of the equipment. We propose a protocol for 222Rn measurement based on three simultaneous integrating radon detectors that may help estimate the proportion of indoor 222Rn derived from the water supply.

  11. Developing soil gas and 222Rn entry potentials for substructure surfaces and assessing 222Rn control diagnostic techniques.

    PubMed

    Turk, B H; Harrison, J; Prill, R J; Sextro, R G

    1990-10-01

    Research-based procedures for characterizing the causes of elevated indoor 222Rn levels and guiding the selection of an appropriate control technique were evaluated at seven New Jersey houses. Procedures such as thorough visual inspections, blower door air leakage tests, pressure field mapping, subsurface vacuum extension tests, sampling of 222Rn concentrations throughout the substructure, and measurements of the additional depressurization caused by various appliances all were found to furnish important information to the mitigation contractor or researcher. An analysis of data from these and other diagnostic techniques performed at the seven houses also indicated: (1) regions of very high permeability existed directly adjacent to the exterior of substructure walls and floors; (2) the additional substructure depressurization caused by operation of forced-air furnaces and attic exhaust fans could exceed 1 Pascal; (3) 222Rn concentrations below basement slabs and slabs-on-grade adjoining below grade basement walls were approximately seven times higher than those within block wall cavities; and (4) air leakage areas of crawlspace and basement ceilings were quite large, ranging up to 0.15 m2. The pressure field mapping tests identified the areas surrounding the substructure that were well coupled to the indoors. Using flow, pressure difference, and 222Rn concentration data, indices of soil gas entry potential and 222Rn entry potential were developed to indicate the areas of the substructure that may have high entry rates of soil gas and 222Rn, respectively. These indices could be helpful for quantifying the relative resistance to soil gas movement of substructure surfaces and surrounding soils and for determining the placement of 222Rn control systems. PMID:2398009

  12. Atmospheric /sup 222/Rn in tourist caves of Slovenia, Yugoslavia

    SciTech Connect

    Kobal, I.; Smodis, B.; Burger, J.; Skofljanec, M.

    1987-04-01

    Radon-222 concentrations in the air of 12 tourist caves in Slovenia, Yugoslavia were measured. In almost all the caves concentrations are higher than in the outdoor air, with the highest concentration in the Tabor Cave at about 6000 Bq m-3. From the /sup 222/Rn concentrations obtained, the activity of /sup 222/Rn inhaled by a visitor breathing cave air was calculated, and the bronchial dose was estimated. The inhaled activity and the bronchial dose were highest in the Tabor Cave with values of 10 kBq and 540 microSv, respectively.

  13. [The content of radon 222Rn in deep borehole water of the Pojezierze Mazurskie terrain].

    PubMed

    Pachocki, K A; Gorzkowski, B; Majle, T; Rózycki, Z

    1997-01-01

    Radon 222Rn in deep borehole water of Pojezierze Mazurskie region has been quantitative determined. The measurement were performed using the alpha liquid scintillation counting method. The water samples were examined from three voivodships: Elblag, Olsztyn and Suwałki. In some cases the concentrations of 222Rn in investigated water samples exceed 11 Bq/l. PMID:9273666

  14. sup 222 Rn, sup 222 Rn progeny and sup 220 Rn progeny as atmospheric tracers of air masses at the Mauno Loa Observatory

    SciTech Connect

    Hutter, A.R.; George, A.C.; Maiello, M.L.; Fisenne, I.M.; Larsen, R.J.; Beck, H.L.; Wilson, F.C.

    1990-03-01

    {sup 222}Rn, {sup 222}Rn progeny and {sup 220}Rn progeny concentrations in air were measured at the Mauna Loa Observatory (MLO) in Hawaii during March 1989 in order to investigate the feasibility of using them as atmospheric tracers to help determine local air mass flow patterns. Charcoal traps, cooled to dry ice temperatures, were used to collect {sup 222}Rn, which was subsequently measured in pulse ionization chambers at the Environmental Measurements Laboratory (EML). {sup 222}Rn progeny and {sup 220}Rn progeny for 37 samples were measured at the Observatory by sampling high volumes of air through filters, which were counted for up to 11 h in alpha scintillation counters. Individual progeny concentrations were calculated using both least squares and maximum likelihood techniques. In general, {sup 222}Rn progeny and {sup 220}Rn progeny concentrations were low when free tropospheric air was present (downslope and tradewind conditions), and consistently higher when surface air from the island broke through the trade wind inversion layer (upslope conditions). The data suggest that {sup 222}Rn, {sup 222}Rn progeny, or {sup 220}Rn progeny monitoring may provide new and useful information to help indicate the different air flow patterns present at MLO. 17 refs., 5 figs., 2 tabs.

  15. 222Rn transport in a fractured crystalline rock aquifer: Results from numerical simulations

    USGS Publications Warehouse

    Folger, P.F.; Poeter, E.; Wanty, R.B.; Day, W.; Frishman, D.

    1997-01-01

    Dissolved 222Rn concentrations in ground water from a small wellfield underlain by fractured Middle Proterozoic Pikes Peak Granite southwest of Denver, Colorado range from 124 to 840 kBq m-3 (3360-22700 pCi L-1). Numerical simulations of flow and transport between two wells show that differences in equivalent hydraulic aperture of transmissive fractures, assuming a simplified two-fracture system and the parallel-plate model, can account for the different 222Rn concentrations in each well under steady-state conditions. Transient flow and transport simulations show that 222Rn concentrations along the fracture profile are influenced by 222Rn concentrations in the adjoining fracture and depend on boundary conditions, proximity of the pumping well to the fracture intersection, transmissivity of the conductive fractures, and pumping rate. Non-homogeneous distribution (point sources) of 222Rn parent radionuclides, uranium and 226Ra, can strongly perturb the dissolved 222Rn concentrations in a fracture system. Without detailed information on the geometry and hydraulic properties of the connected fracture system, it may be impossible to distinguish the influence of factors controlling 222Rn distribution or to determine location of 222Rn point sources in the field in areas where ground water exhibits moderate 222Rn concentrations. Flow and transport simulations of a hypothetical multifracture system consisting of ten connected fractures, each 10 m in length with fracture apertures ranging from 0.1 to 1.0 mm, show that 222Rn concentrations at the pumping well can vary significantly over time. Assuming parallel-plate flow, transmissivities of the hypothetical system vary over four orders of magnitude because transmissivity varies with the cube of fracture aperture. The extreme hydraulic heterogeneity of the simple hypothetical system leads to widely ranging 222Rn values, even assuming homogeneous distribution of uranium and 226Ra along fracture walls. Consequently, it is

  16. Measurements of 222Rn activity in well water of the Curitiba metropolitan area (Brazil)

    NASA Astrophysics Data System (ADS)

    Corrêa, Janine N.; Paschuk, Sergei A.; Kappke, Jaqueline; Perna, Allan F. N.; França, Alana C.; Schelin, Hugo R.; Denyak, Valeriy

    2014-11-01

    Considering that 222Rn activity concentration in well water can contribute to indoor radon concentration levels, which represent a radiation risk for the public, measurements of 226Ra and 222Rn activity in well water in Curitiba, Paraná State, Brazil were performed. Each water sample was submitted to four measurements for radon concentration over an interval of three days. After two months, the same samples were submitted again to 222Rn concentration measurements with the objective of indirectly evaluating the amount of 226Ra in them. The 222Rn concentration measurements were performed with an AlphaGUARD radon monitor (SAPHYMO), and the 226Ra concentration was evaluated with the decay curves of 222Rn. Within a few hours after extraction, about 70% of water samples from monitored wells presented 222Rn concentration values above the limit of 11.1 Bq/L recommended by the EPA of the United States. The obtained activity values varied between 1.6 Bq/L and 215 Bq/L for radon concentration, and radium concentrations deviated within an interval of 0.50 Bq/L and 6.8 Bq/L. The results reveal that the biggest part of 222Rn found in water samples originated not from soluble 226Ra compounds but from gas exhalation by the soil and rocks adjacent to the well. The results point to the necessity of mitigation procedure development for better control of global alpha radioactivity in drinking water.

  17. An electrostatic integrating 222Rn monitor with cellulose nitrate film for environmental monitoring.

    PubMed

    Iida, T; Ikebe, Y; Hattori, T; Yamanishi, H; Abe, S; Ochifuji, K; Yokoyama, S

    1988-02-01

    This paper describes a new type of electrostatic integrating 222Rn monitor designed for the environmental 222Rn monitoring. The window area of the monitor was selected to make the exchange rate optimal. The collecting electrode was positioned on the basis of calculating the internal electric field. A drying agent, P2O5, was placed in the bottom of the monitor, since the collection efficiency of 218Po+ atoms depends on the humidity of the air. The monitors have been calibrated against known 222Rn exposures. The detection limit is 1.2 Bq m-3 for an exposure time of 2 mo. In a small survey, annual mean 222Rn concentrations between 3.7 and 9.5 Bq m-3 in outdoor air and between 6.4 and 11.9 Bq m-3 in indoor air were measured. PMID:3338911

  18. Measurements of soil and canopy exchange rates in the Amazon rain forest using 222Rn

    NASA Astrophysics Data System (ADS)

    Trumbore, S. E.; Keller, M.; Wofsy, S. C.; da Costa, J. M.

    1990-09-01

    Measurements of the emission of 222Rn from Amazon forest soils, and profiles of 222Rn in air were used to study the ventilation of the soil atmosphere and the nocturnal forest canopy. The emission of 222Rn from the yellow clay soils dominant in the study area averaged 0.38±0.07 atom cm-2 s-1. Nearby sand soils had similar fluxes, averaging 0.30 ± 0.07 atom cm-2 s-1. The effective diffusivity in the clay soil (0.008±0.004 cm2 s-1), was lower than that for the sand soil (0.033±0.030 cm2 s-1). Profiles of 222Rn and CO2 in air showed steepest concentration gradients in the layer between 0 and 3 m above the soil surface. Aerodynamic resistances calculated for this layer from 222Rn and CO2 varied from 1.6 to 18 s cm-1, with greater resistance during the afternoon than at night. Time averaged profiles of 222Rn in the forest canopy measured during the evening and night were combined with the soil flux measurements to compute the resistance of the subcanopy to exchange with overlying air. The integrated nocturnal rate of gas exchange between the canopy layer (0 to 41 m) and overlying atmosphere based on 222Rn averaged 0.33±0.15 cm s-1. An independent estimate of gas exchange, based on 13 nights of CO2 profiles, averaged 0.21±0.40 cm s-1. These exchange rates correspond to flushing times for the 41 m canopy layer of 3.4 and 5.5 hours, respectively. Comparison of 222Rn and CO2 profiles show that the nocturnal production of CO2 by above-ground vegetation was about 20% of the soil emission source, consistent with data from eddy-correlation experiments (Fan et al., this issue).

  19. A follow-up study on indoor 222Rn, 220Rn their decay product concentrations in a mineralised zone of Himachal Pradesh, India.

    PubMed

    Bajwa, B S; Singh, Parminder; Singh, Prabhjot; Saini, Komal; Singh, Surinder; Sahoo, B K; Sapra, B K

    2016-03-01

    A follow-up study was taken up in a mineralised zone situated in Hamirpur district, Himachal Pradesh, India, to investigate high values of radon concentrations reported in past studies as well to update the old radon data based on bare SSNTD technique. In the present investigation, the concentrations of indoor radon, thoron and their decay products have been measured using the newly developed radon/thoron discriminating diffusion chamber with single entry face, direct radon and thoron progeny sensors (DRPS/DTPS), respectively. The measurements have been carried out in 75 dwellings of 14 different villages where the previous studies were carried out using bare SSNTD technique. It was observed that high values of earlier reported radon concentrations were mainly due to thoron interference in the Solid State Nuclear Track Detector (LR-115 type II) exposed in bare mode. Now, the average concentration values and the estimated annual inhalation dose in these villages have been found to be within the reference level as recommended by the ICRP. The annual average indoor radon and thoron concentrations observed in these dwellings have been found to vary from 44±12 to 157±73 Bq m(-3) and 44±11 to 240±125 Bq m(-3), respectively. The equilibrium equivalent concentrations of radon and thoron decay products have been observed to be in the range of 10 to 63 and 1 to 5 Bq m(-3), respectively. PMID:26184660

  20. Radon and thoron in cave dwellings (Yan'an, China)

    SciTech Connect

    Wiegand, J.; Feige, S.; Xie Quingling; Schreiber, U.; Wieditz, K.; Wittmann, C.; Luo Xiarong

    2000-04-01

    {sup 222}Rn and {sup 220}Rn concentrations were measured in cave dwellings and brick houses in the region of Yan'an (China) during summer 1997. The underground dwellings are built into Quaternary loess, and all investigated houses are founded on it. The median values of indoor {sup 222}Rn and {sup 220}Rn concentrations are 42 (n = 18) and 77Bq m{sup {minus}3} (n = 15) for brick houses and 92 (n = 23) and 215 (n = 17) Bq m{sup {minus}3} for cave dwellings. To classify the dwellings in respect to their cave-character, the fraction of walls having a direct contact to the loess is calculated for each dwelling. While the {sup 222}Rn concentrations are increasing with higher fractions, the {sup 220}Rn concentrations are not correlated with this fraction. On the other hand, due to the short half-life of {sup 220}Rn the distance from the measuring point to the walls is negatively correlated with the {sup 220}Rn concentration, while there is no correlation with the {sup 222}Rn concentration. Therefore, concentric isolines of {sup 220}Rn concentrations showing a strong gradient were detected in cave dwellings. An influence of the ventilation rate is distinct for {sup 222}Rn but weak for {sup 220}Rn. The effective dose rates for {sup 222}Rn and {sup 220}Rn and their progenies are calculated for brick houses (2.7 mSv y{sup {minus}1}), cave dwellings (7.1 mSv y{sup {minus}1}), and for traditional cave dwellings with a bed foundation built with loess (16.7 mSv y{sup {minus}1}). These calculations are based on summer measurements only. It is expected that the true effective dose rates will be significantly higher.

  1. Soil radon ( 222 Rn) monitoring at Furnas Volcano (São Miguel, Azores): Applications and challenges

    NASA Astrophysics Data System (ADS)

    Silva, C.; Ferreira, T.; Viveiros, F.; Allard, P.

    2015-05-01

    A soil 222Rn continuous monitoring test was performed in three sampling points inside Furnas Volcano caldera and 222Rn concentration varied between 0 and 153000 Bq/m3. Multivariate regression and spectral analyses were applied to the time series registered in order to understand and filter the influence of external factors on soil 222Rn concentration and to recognise anomalies correlated with deep processes. The regression models show that barometric pressure, soil water content, soil temperature, soil CO2 flux, air temperature, relative air humidity and wind speed are the statistical meaningful variables explaining between 15.8% and 73.6% of 222Rn variations. Spectral analysis allowed to identify seasonal variations and daily variations associated with one cycle per day on winter months only in one of the monitored sites. This diurnal variation is correlated with air temperature, relative air humidity and wind speed cycles. The change in the location of the sampling points was caused by both artificial and natural constrains. On the three monitoring sites, after a period of continuous register, a sudden drop on the 222Rn concentration values was observed and the cause is still under debate. The work performed can be applied for seismovolcanic monitoring and for public health risk assessment.

  2. Apparatus for the Measurement of {sup 222}Rn Diffusion

    SciTech Connect

    Mamedov, F.; Konicek, J.; Stekl, I.

    2009-11-09

    A new apparatus for the measurement of {sup 222}Rn diffusion through shielding foils developed in the frame of the NEMO collaboration is briefly described. The setup is based on the electrostatic collection of radon progenies {sup 218}Po and {sup 214}Po. The NEMO project is an underground experiment for the study of double beta decay processes. For such type of experiments the efficient suppression of background caused by radon is essential. The first test of the apparatus has been carried out using Penefol foil (0.8 mm thickness) and the suppression factor of radon concentration has been obtained.

  3. Gas exchange in the Pee Dee River based on /sup 222/Rn evasion

    SciTech Connect

    Moore, W.S.; Elsinger, R.J.

    1983-06-01

    Excess /sup 222/Rn concentrations decrease downstream in the fresh water section of the Pee Dee River. Ground water is the primary source of the excess /sup 222/Rn to the River. Using the radon concentration gradients determined during four sampling periods, gas exchange rates based on the stagnant film model are calculated. Stagnant film thicknesses range from 19 ..mu..m to 48 ..mu..m and mass transfer coefficients range from 2.1 m/d to 4.1 m/d.

  4. Comparative performance of short-term diffusion barrier charcoal canisters and long-term alpha-track monitors for indoor 222Rn measurements.

    PubMed

    Martz, D E; George, J L; Langner, G H

    1991-04-01

    The accuracy and precision of indoor 222Rn measurements obtained with the use of diffusion barrier charcoal canisters (DBCC) under actual field conditions were determined by comparing the integrated average of 26 successive 7-d exposures of DBCC in each of 16 occupied residences over a 6-mo period with simultaneous measurements using four types of commercially available alpha-track monitors (ATM) and one type of scintillation chamber continuous 222Rn monitor. The results suggest that properly calibrated DBCCs provide very good estimates of the integrated 222Rn concentrations in residential structures over the standard 1-wk exposure period despite the occurrence of large diurnal variations in the actual 222Rn concentrations. The results also suggest that a relatively small number of 1-wk DBCC measurements at selected times throughout the calendar year would provide estimates of the annual average indoor 222Rn concentrations that compare favorably with single long-term ATM measurements. PMID:2001945

  5. Comparative performance of short-term diffusion barrier charcoal canisters and long-term alpha-track monitors for indoor sup 222 Rn measurements

    SciTech Connect

    Martz, D.E.; George, J.L.; Langner, G.H. Jr. )

    1991-04-01

    The accuracy and precision of indoor {sup 222}Rn measurements obtained with the use of diffusion barrier charcoal canisters (DBCC) under actual field conditions were determined by comparing the integrated average of 26 successive 7-d exposures of DBCC in each of 16 occupied residences over a 6-mo period with simultaneous measurements using four types of commercially available alpha-track monitors (ATM) and one type of scintillation chamber continuous {sup 222}Rn monitor. The results suggest that properly calibrated DBCCs provide very good estimates of the integrated {sup 222}Rn concentrations in residential structures over the standard 1-wk exposure period despite the occurrence of large diurnal variations in the actual {sup 222}Rn concentrations. The results also suggest that a relatively small number of 1-wk DBCC measurements at selected times throughout the calendar year would provide estimates of the annual average indoor {sup 222}Rn concentrations that compare favorably with single long-term ATM measurements.

  6. Measurements of soil and canopy exchange rates in the Amazon rain forest using sup 222 Rn

    SciTech Connect

    Trumbore, S.E. Lamont-Doherty Geological Observatory, Palisades, NY ); Keller, M. ); Wofsy, S.C. ); Da Costa, J.M. )

    1990-09-20

    Measurements of the emission of {sup 222}Rn from Amazon forest soils, and profiles of {sup 222}Rn in air were used to study the ventilation of the soil atmosphere and the nocturnal forest canopy. The emission of {sup 222}Rn from the yellow clay soils dominant in the study area averaged 0.38 {plus minus} 0.07 atom cm{sup {minus}2} s{sup {minus}1}. Nearby sand soils had similar fluxes, averaging 0.30 {plus minus} 0.07 atom cm{sup {minus}2} s{sup {minus}1}. The effective diffusivity in the clay soil (0.008 {plus minus} 0.004 cm{sup 2} s{sup {minus}1}), was lower than that for the sand soil (0.033 {plus minus} 0.030 cm{sup 2} s{sup {minus}1}). Profiles of {sup 222}Rn and CO{sub 2} in air showed steepest concentration gradients in the layer between 0 and 3 m above the soil surface. Aerodynamic resistances calculated for this layer from {sup 222}Rn and CO{sub 2} varied from 1.6 to 18 s cm{sup {minus}1}, with greater resistance during the afternoon than at night. Time averaged profiles of {sup 222}Rn in the forest canopy measured during the evening and night were combined with the soil flux measurements to compute the resistance of the subcanopy to exchange with overlying air. The integrated nocturnal rate of gas exchange between the canopy layer (0 to 41 m) and overlying atmosphere based on {sup 222}Rn averaged 0.33 {plus minus} 0.15 cm s{sup {minus}1}. An independent estimate of gas exchange, based on 13 nights of CO{sub 2} profiles, averaged 0.21 {plus minus} 0.40 cm s{sup {minus}1}. These exchange rates correspond to flushing times for the 41 m canopy layer of 3.4 and 5.5 hours, respectively. Comparison of {sup 222}Rn and CO{sub 2} profiles show that the nocturnal production of CO{sub 2} by above-ground vegetation was about 20% of the soil emission source, consistent with data from eddy-correlation experiments.

  7. INDOOR 222RN IN TENNESSEE VALLEY HOUSES: SEASONAL, BUILDING AND GEOLOGICAL FACTORS

    EPA Science Inventory

    A two-season survey of indoor 222Rn concentrations was conducted in 226 occupied houses in Roane County, TN, during 1985 and 1986. A similar survey of 86 houses in Madison County, AL, was conducted in 1988 and 1989. Alpha track detectors were placed in each of the houses for thre...

  8. One year of real-time radon monitoring at Stromboli volcano and the effect of environmental parameters on 222Rn concentrations

    NASA Astrophysics Data System (ADS)

    Cigolini, C.; Laiolo, M.; Coppola, D.; Piscopo, D.; Bertolino, S.

    2009-12-01

    Real-time radon monitoring at Stromboli volcano has been operative within the last two years. In this contribution we will discuss the recent one-year-long time series analyses in the light of environmental parameters. Two sites for real-time monitoring have been identified by means of a network of periodic radon surveys in order to locate the areas of more efficient response to seismic transients and/or volcanic degassing. Two real-time stations are positioned at Stromboli: one at the summit and located along a fracture zone where the gas flux is concentrated, and the second one at a lower altitude in a sector of diffuse degassing. The signals of the two time-series are essentially concordant but radon concentrations are considerably higher at the summit station. Raw data show that there is a negative correlation between radon emissions and seasonal temperature variations, whereas the correlation with atmospheric pressure is negative for the site of diffuse degassing and sligthly positive for the station lacated along the summit fracture zone. These data and the previously collected ones show that SW winds may substantially decrease radon concentrations at the summit station. Multivarite regression statistics on the radon signals in the light of the above enviromental parameters and tidal forces, may contribute to better idenfify the correlation between radon emissions and variations in volcanic activity. Fig. 1. Radon monitoring stations at Stromboli and the two major summit faults. Stars identify sites for real-time monitoring: LSC and PZZ. The diamond is the location of the automated Labronzo Station. Full dots are stations for periodic measurements using alpha track-etches detectors and E-PERM® electrets. Inset with the location of Stromboli and the major structures of the Aeolian arc.

  9. Surface-deposition and Distribution of the Radon (222Rn and 220Rn) Decay Products Indoors

    NASA Astrophysics Data System (ADS)

    Espinosa, G.; Tommasino, Luigi

    The exposure to radon (222Rn and 220Rn) decay products is of great concern both in dwellings and workplaces. The model to estimate the lung dose refers to the deposition mechanisms and particle sizes. Unfortunately, most of the dose data available are based on the measurement of radon concentration and the concentration of radon decay products. These combined measurements are widely used in spite of the fact that accurate dose assessments require information on the particle deposition mechanisms and the spatial distribution of radon decay products indoors. Most of the airborne particles and/or radon decay products are deposited onto indoor surfaces, which deposition makes the radon decay products unavailable for inhalation. These deposition processes, if properly known, could be successfully exploited to reduce the exposure to radon decay products. In spite of the importance of the surface deposition of the radon decay products, both for the correct evaluation of the dose and for reducing the exposure, little or no efforts have been made to investigate these deposition processes. Recently, two parallel investigations have been carried out in Rome and at Universidad Nacional Autónoma de México (UNAM) in Mexico City respectively, which address the issue of the surface-deposited radon decay products. Even though these investigations have been carried independently, they complement one another. It is with these considerations in mind that it was decided to report both investigations in the same paper.

  10. Two-filter monitor for atmospheric 222Rn

    NASA Astrophysics Data System (ADS)

    Schery, S. D.; Gaeddert, D. H.; Wilkening, M. H.

    1980-03-01

    A two-filter, continuous monitor has been developed for atmospheric 222Rn. Features include a sensitivity of better than 0.01 pCi/l, a high specificity for 222Rn, and immediate start up capability. The monitor has been computer modeled to facilitate calibration and selection of operating parameters. The filters are stationary and require no moving parts for control. Field trials indicate high reliability and maintenance-free operation for periods of a week and longer.

  11. Surface radioactivity resulting from the deposition of /sup 222/Rn daughter products

    SciTech Connect

    Lively, R.S.; Ney, E.P.

    1987-04-01

    This paper describes the relationship between the /sup 222/Rn in air, and the level of surface radioactivity that results from the build-up and decay of the daughter isotope, /sup 210/Pb. Samples of /sup 222/Rn were collected from Mystery Cave, which is located in southeastern Minnesota and from the basement of a house in Minneapolis, MN. Lead-210 was measured on surfaces within the cave, on a rock removed from the cave, and on a basement window. Surface alpha activities were measured on the rock sample and on the window. Radon-222 concentrations in the cave air ranged from 3 to 13 kBq m-3. In the basement, /sup 222/Rn levels were between 0.2 and 0.4 kBq m-3. Virtually all the surface radioactivity resulted from the deposition and decay of airborne /sup 222/Rn daughter products and was not produced by the decay of U in the rock. Radon-222 concentrations in the cave air were almost 30 times higher than in the basement air; however, the surface /sup 210/Pb activity in the cave was 100 times higher than that in the basement. This suggests that in the cave air, /sup 222/Rn daughter products are more likely to reach the walls and decay to /sup 210/Pb. The measurements of surface alpha activity did not show a similar trend primarily because /sup 210/Pb had diffused further into the coating of dirt on the rock than into the glass of the window. The resulting surface activity of the rock was lower than expected based on the /sup 210/Pb concentration, because many of the alpha-emitting nuclei were at depths beyond the range of emitted alpha particles. On surfaces where the penetration range of alpha particles is greater than the diffusion depth of /sup 210/Pb atoms, either the /sup 210/Pb concentration or surface alpha-activity measurements should provide estimates of average long-term /sup 222/Rn concentrations.

  12. The Effect of CO2 on the Measurement of 220Rn and 222Rn with Instruments Utilising Electrostatic Precipitation

    DOE PAGESBeta

    Lane-Smith, Derek; Sims, Kenneth

    2013-06-09

    In some volcanic systems, thoron and radon activity and CO2 flux, in soil and fumaroles, show a relationship between (220Rn/222Rn) and CO2 efflux. It is theorized that deep, magmatic sources of gas are characterized by high 222Rn activity and high CO2 efflux, whereas shallow sources are indicated by high 220Rn activity and relatively low CO2 efflux. In this paper we evaluate whether the observed inverse relationship is a true geochemical signal, or potentially an analytical artifact of high CO2 concentrations. We report results from a laboratory experiment using the RAD7 radon detector, known 222Rn (radon) and 220Rn (thorn), and amore » controllable percentage of CO2 in the carrier gas. Our results show that for every percentage of CO2, the 220Rn reading should be multiplied by 1.019, the 222Rn radon should be multiplied by 1.003 and the 220Rn/222Rn ratio should be multiplied by 1.016 to correct for the presence of the CO2.« less

  13. A high-sensitivity method for the measurement of 222Rn based on liquid scintillation counting of polycarbonate powder.

    PubMed

    Mitev, K; Georgiev, S; Pressyanov, D; Dimitrova, I; Zhivkova, V; Boshkova, T

    2014-07-01

    This work describes a technique for the measurement of 222Rn by absorption in polycarbonate (PC) powder and liquid scintillation counting (LSC). The work is an improvement of the recently proposed method for 222Rn measurements by LSC of exposed PC grains. It is demonstrated that the use of PC powder as a 222Rn sampler improves 13.6 times the sampling efficiency and leads to 6.5 times smaller minimmal detectable activity concentrations (MDAC) compared with the PC grains used so far. For a 40-h exposure of 7.4-g PC powder to 222Rn in air, the MDAC with a RackBeta 1219 LS counter is 62 Bq m(-3) (assuming a 8-h sample counting time and 24-h background time). For the same conditions the estimated 222Rn MDAC with a Quantulus 1220 LS counter is 20 Bq m(-3). The proposed technique is suitable for radon in air and radon in soil-gas measurements. PMID:24723190

  14. Determination of (222)Rn absorption properties of polycarbonate foils by liquid scintillation counting. Application to (222)Rn measurements.

    PubMed

    Mitev, K; Cassette, P; Georgiev, S; Dimitrova, I; Sabot, B; Boshkova, T; Tartès, I; Pressyanov, D

    2016-03-01

    This work demonstrates that a Liquid Scintillation Counting (LSC) technique using a Triple to Double Coincidence Ratio counter with extending dead-time is very appropriate for the accurate measurement of (222)Rn activity absorbed in thin polycarbonate foils. It is demonstrated that using a toluene-based LS cocktail, which dissolves polycarbonates, the (222)Rn activity absorbed in thin Makrofol N foil can be determined with a relative standard uncertainty of about 0.7%. A LSC-based application of the methodology for determination of the diffusion length of (222)Rn in thin polycarbonate foils is proposed and the diffusion length of (222)Rn in Makrofol N (38.9±1.3µm) and the partition coefficient of (222)Rn in Makrofol N from air (112±12, at 20°C) and from water (272±17, at 21°C) are determined. Calibration of commercial LS spectrometers for (222)Rn measurements by LSC of thin polycarbonate foils is performed and the minimum detectable activities by this technique are estimated. PMID:26640234

  15. (The determination of sup 222 Rn flux from soils based on sup 210 Pb and sup 226 Ra disequilibrium)

    SciTech Connect

    Turekian, K.K.

    1991-01-01

    The emanating fraction of radon in soils from the southern part of the United States is about 40% greater than in those from the northern part. The mean {sup 226}Ra activity in the southern soils is also slightly higher and as a consequence the {sup 222}Rn flux derived from the top 50 cm. is greater in the southern samples. We tentatively attribute these observations to the greater degree of weathering associated with the pre-glacial age of the parent material of many of the southern soils. The weathering has concentrated {sup 226}Ra near grain surfaces and results in an increased emanating power for {sup 222}Rn. The estimated correction in {sup 210}Pb analyses described above results in a small decrease in our estimate of the mean loss rate of {sup 222}Rn from the upper 50 cm of soils.

  16. Summertime elevation of sup 222 Rn levels in Huntsville, Alabama

    SciTech Connect

    Wilson, D.L.; Gammage, R.B.; Dudney, C.S.; Saultz, R.J. )

    1991-02-01

    Indoor Rn concentrations and Rn in adjacent karst terrains were studied at four houses with crawlspaces in Huntsville, AL. In warm summertime weather, Rn-rich air may vent through limestone solution cavities exposed as holes at the surface of the properties. A probable interrelated-finding is that the indoor levels of {sup 222}Rn are distinctly higher in the summer than winter. The karst underlying the homes is structurally faulted and, in all probability, facilitates Rn transport from the solution cavities to the crawlspaces. Abrupt day-to-day changes in indoor Rn concentrations were recorded in addition to large seasonal changes. If the owners or residents of these particular homes had attempted to make, and interpret, short-term screening measurements for Rn during the fall season, problems, including false negatives, could have arisen because of order-of-magnitude changes in Rn concentration occurring over a few days. The best time of year to make screening measurements would be during the summer when indoor Rn concentrations are more likely to reach their maximum values.

  17. {sup 222}Rn Measurements at Federal University of Technology (UTFPR, Curitiba, PR, Brazil)

    SciTech Connect

    Correa, Janine Nicolosi; Paschuk, Sergei A.; Fior, Loriane; Schelin, Hugo R.; Flores da Silva, Ruben D.; Poettker, Fabiana; Paula Melo, Vicente de

    2008-08-07

    Numerous studies and reports indicate that the indoor radon inhalation by humans has to be considered as the main source of radiological hazard and probably the second most important cause of lung cancer after that of smoking. During the last decades, many countries have put considerable efforts into direct measurements and monitoring of {sup 222}Rn and its progeny exposure, as well as {sup 222}Rn concentration mapping. Present measurements were performed with an aim to study possible correlation between used construction materials and {sup 222}Rn indoor concentration levels. For this purpose, 50 Lexan track detectors were exposed in the air (indoor as well as outdoor) during two months (June and July) within the central region of Curitiba and Campo Largo (Parana St., Brazil). Since this period of the year is usually rather cold in the South of Brazil, exposition time was chosen to prevent possible saturation of alpha tracks. The second step of measurements was performed during the months of November, December and January, when 50 Lexan track detectors were exposed in the air (indoor and outdoor) within the same urban area. Achieved results are being compared with other experimental data.

  18. Determination of 210Pb and 222Rn in ground water of Okinawa Island

    NASA Astrophysics Data System (ADS)

    Ito, M.; Tanahara, A.

    2012-12-01

    In this study, we developed the method of 210Pb measurement from a large amount of ground water. The chelating resin (NOBIAS CHELATE-PA1; Hitachi High-technology) column combined with the ion-exchange resin (DOWEX-88; Dow Chemical Company) column were used for pre-treatment of 210Pb from ground water of 20 litter. It should be mentioned that this determination procedure is simple, fast, and give high recovery (more than 80 %). It avoids precipitation and large consumption of chemicals. Finally 210Pb was precipitated as PbSO4 and determined with low background 2πgas flow counter. 210Pb concentration in ground water of Okinawa Island ranged from 1.40-16.7 mBq/L. We also found that the organo-210Pb complex which could not be detected by this method was involved in some water samples. By increasing the column radius and the resin mass, while keeping a constant height of the resin column, it is possible to additionally increase the flow rate and accelerate the isolation procedure. 222Rn was determined by the direct method. The emulsion scintillation cocktail (10 mL) and water sample (10 mL) were put into a vial. After shaking and stand for 200 min, 222Rn was counted by LSC for 120 min. 222Rn concentration in ground water of Okinawa Island ranged from 0.71-14.0 Bq/L.

  19. 222Rn Measurements at Federal University of Technology (UTFPR, Curitiba, PR, Brazil)

    NASA Astrophysics Data System (ADS)

    Corrêa, Janine Nicolosi; Paschuk, Sergei A.; Fior, Loriane; Schelin, Hugo R.; da Silva, Ruben D. Flores; Pöttker, Fabiana; de Paula Melo, Vicente

    2008-08-01

    Numerous studies and reports indicate that the indoor radon inhalation by humans has to be considered as the main source of radiological hazard and probably the second most important cause of lung cancer after that of smoking. During the last decades, many countries have put considerable efforts into direct measurements and monitoring of 222Rn and its progeny exposure, as well as 222Rn concentration mapping. Present measurements were performed with an aim to study possible correlation between used construction materials and 222Rn indoor concentration levels. For this purpose, 50 Lexan track detectors were exposed in the air (indoor as well as outdoor) during two months (June and July) within the central region of Curitiba and Campo Largo (Parana St., Brazil). Since this period of the year is usually rather cold in the South of Brazil, exposition time was chosen to prevent possible saturation of alpha tracks. The second step of measurements was performed during the months of November, December and January, when 50 Lexan track detectors were exposed in the air (indoor and outdoor) within the same urban area. Achieved results are being compared with other experimental data.

  20. Occurrence of 222Rn in irrigation water from Wadi Al-Rummah Qassim province, Saudi Arabia

    NASA Astrophysics Data System (ADS)

    El-Taher, Atef; Alashrah, Saleh

    2015-08-01

    Naturally accruing radioactive materials in the environment have received attention since they may be present in high level and pose risk to human health. The present work deals with measuring of 222Rn in irrigation water samples from Wadi Al-Rummah, Qassim province, in central of Saudi Arabia. 222Rn concentrations were measured by RAD7. It was found that the concentration of 222Rn ranged from 2.1 ± 1.2 to 7.2 ± 1.5 BqL-1. These values are below 11.1 BqL-1 the maximum contamination level recommended from the U.S. Environmental Protection Agency. The calculated annual effective dose (AED) ranging from 7.5 to 26.1 µSv/y. It was evident that the total annual effective dose resulting from radon in irrigation groundwater in Wadi Al-Rummah in Qassim area were significantly lower than the recommended limit 1 mSv/y for the public.

  1. Behaviour of {sup 222}Rn at cryogenic temperatures

    SciTech Connect

    Lindemann, Sebastian; Simgen, Hardy; Zuzel, Grzegorz

    2011-04-27

    The behaviour of radon in a cryogenic environment is still not well known. Therefore, measured radon emanation rates at room temperature cannot be translated directly to cryogenic conditions. In this work we present a table-top experiment that provides a direct way of determining the behaviour of {sup 222}Rn in cryogenic argon and helium at liquid argon temperature. We observe an increased emanation rate of {sup 222}Rn atoms to liquid argon compared to the rate observed to helium at room temperature. We also find that {sup 222}Rn atoms stick to cold metal surfaces when emanated to helium at liquid argon temperature but partly distribute in the liquid when emanated to cryogenic argon. Concluding, we give possible interpretations of the observations.

  2. A micromegas detector for {sup 222}Rn emanations measurements

    SciTech Connect

    García, J. A.; Garza, J. G.; Irastorza, I. G.; Mirallas, H.

    2013-08-08

    The {sup 222}Rn emanation has significant contribution in the overall background for rare event searches experiments. In order to measure this emanations a high sensitivity detector has been designed. The detection method is based on the electrostatic collection of the {sup 222}Rn daughters on a Micromegas detector. Using a chamber with a volume of 21.2 l for the collection of {sup 218}Po and {sup 214}Po progeny of {sup 222}Rn and a 12 × 12cm{sup 2} pixelized Micromegas for the α detection. The advantages of the Micromegas detectors are the low intrinsic radioactivity and the track reconstruction of the α’s, having excellent capabilities for event discrimination.

  3. Highly Sensitive Measurements of 222Rn Diffusion and Emanation

    SciTech Connect

    Zuzel, Grzegorz

    2005-09-08

    Highly sensitive techniques for determination of the 222Rn emanation from solids and diffusion through different membranes are presented. 222Rn and its daughters are measured via the alpha decays in special proportional counters at the absolute sensitivity of {approx}30 {mu}Bq. Radon diffusion can be measured at the level of {approx}10-13 cm2/s. Several samples were examined, e.g. stainless steel, teflon, various gaskets (emanation and diffusion measurements) and tanks. A combination of measurements of the 222Rn diffusion and emanation of thin nylon foils (used in the Borexino experiment) allowed the determination of 226Ra in the materials of interest at the level of {approx}10-12 g/g 238U-equivalent.

  4. 222Rn and 212Pb exposures at a Brazilian spa.

    PubMed

    Campos, M P; Pecequilo, B R S; Mazzilli, B P

    2010-09-01

    Termas de Araxá spa is located in Araxá, State of Minas Gerais. In this region, several minerals rich in uranium and thorium are found. The mineral waters and mud from Termas de Araxá spa have been used for therapeutic and recreation purposes. In this study, the committed effective dose was evaluated for workers and patients at Araxá spa due to (222)Rn and (212)Pb inhalation. Radon measurements were carried out through the passive method with solid state nuclear track detectors (Makrofol E) over a period of 21 months, with results varying from 258 +/- 20 to 1634 +/- 111 Bq m(-3). The (212)Pb air concentration was assessed through the modified Kusnetz's method, the results varying from 0.3 +/- 0.1 to 2.1 +/- 0.2 Bq m(-3). Doses received by the spa workers are below 20 mSv.y(-1), suggested by ICRP 60 as an annual effective dose limit for occupational exposure. The radiation doses for the patients are below the mean annual effective dose due to natural sources estimated to be 2.4 mSv.y(-1). PMID:20513732

  5. Estimation of submarine groundwater discharge and associated nutrient fluxes in eastern Laizhou Bay, China using 222Rn

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Li, Hailong; Wang, Xuejing; Zheng, Chunmiao; Wang, Chaoyue; Xiao, Kai; Wan, Li; Wang, Xusheng; Jiang, Xiaowei; Guo, Huaming

    2016-02-01

    There is increasing evidence that the inputs of nutrients to the Bohai Sea are closely related to submarine groundwater discharge (SGD). In this study, the naturally occurring isotope of radon (222Rn) was used as a tracer to assess SGD in eastern Laizhou Bay. The 222Rn concentration during a tidal period was measured continuously and a mass balance model that included atmospheric loss, tidal effects, mixing loss, diffusion from sediments, and SGD was established. The model budget indicated that 222Rn flux attributed to SGD accounted for 58.3% of the total tracer input to the study area. The time-series of 222Rn revealed that the SGD flux ranged from 6.64 to 7.21 cm d-1, with an average of 6.93 cm d-1, in September 2014. The estimated SGD flux is reasonable compared with those previously estimated in other studies by direct measurement methods, hydrogeological simulation and geochemical tracers. This result, as well as the current understanding of nutrients dissolved in groundwater, confirms the importance of SGD in delivering nutrients to Laizhou Bay and possible impact on marine ecological environment.

  6. A theoretical model for {sup 222}Rn adsorption on activated charcoal canisters in humid air based on Polanyi`s potential theory

    SciTech Connect

    Scarpitta, S.C.

    1995-03-01

    Water vapor interferes with adsorption {sup 222}Rn gas by passive activated charcoal devices used to estimate indoor air concentrations. The {sup 222}Rn adsorption coefficient is the fundamental parameter characterizing charcoal`s ability to adsorb {sup 222}Rn. The Dubinin-Radushkevich equation, based on Polanyi`s potential theory, was modified to include two terms quantifying the effect of both water vapor and sampling time on the {sup 222}Rn adsorption coefficient of passive charcoal devices. A single equation was derived that quantities the {sup 222}Rn adsorption coefficients at any temperature, humidity and exposure time using six experimentally determined physical constants that are unique for a particular passive charcoal device. The theoretical model was verified with published experimental data, and it showed a good correlation between theory and experiment. The model proved to be consistent with experimental data, provided that the amount of water vapor adsorbed by the charcoal device during sampling remains below a critical level, termed the breakpoint. 44 refs., 5 figs., 2 tabs.

  7. Estimation of 222Rn release from the phosphogypsum board used in housing panels.

    PubMed

    Jang, Mee; Kang, Chang-Sun; Hyun Moon, Joo

    2005-01-01

    Phosphogypsum board is a popular construction material used for housing panels in Korea. Phosphogypsum often contains (226)Ra which decays into (222)Rn through an alpha transformation. (222)Rn emanated from the (226)Ra-bearing phosphogypsum board has drawn the public concern due to its potential radiological impacts to indoor occupants. The emanation rate of (222)Rn from the board is estimated in this paper. A mathematical model of the emanation rate of (222)Rn from the board is presented and validated through a series of experiments. The back diffusion effect due to accumulation of (222)Rn-laden air was incorporated in the model and found to have a strong impact on the (222)Rn emanation characteristics. PMID:15701380

  8. [The determination of {sup 222}Rn flux from soils based on {sup 210}Pb and {sup 226}Ra disequilibrium]. Progress report

    SciTech Connect

    Turekian, K.K.

    1991-12-31

    The emanating fraction of radon in soils from the southern part of the United States is about 40% greater than in those from the northern part. The mean {sup 226}Ra activity in the southern soils is also slightly higher and as a consequence the {sup 222}Rn flux derived from the top 50 cm. is greater in the southern samples. We tentatively attribute these observations to the greater degree of weathering associated with the pre-glacial age of the parent material of many of the southern soils. The weathering has concentrated {sup 226}Ra near grain surfaces and results in an increased emanating power for {sup 222}Rn. The estimated correction in {sup 210}Pb analyses described above results in a small decrease in our estimate of the mean loss rate of {sup 222}Rn from the upper 50 cm of soils.

  9. Integrated measurements of short-lived 222Rn progeny by rotating filters.

    PubMed

    Pressyanov, D S; Guelev, M G; Pentchev, O J

    1993-05-01

    The dependence of the risk from inhalation of radon progeny on their disequilibrium suggests that the measurements of the time-integrated concentrations of each of the short-lived radon progeny are necessary for complete risk estimations. This paper presents a method that, in principle, allows the determination of the integrated specific volume activities in air of each of the radionuclides 218Po, 214Pb, 214Bi, 212Pb, and 212Bi. The method employs thermoluminescence detectors positioned around uniformly rotating filters. Two prototypes that are suitable for practical applications are described and mathematical expressions for data processing are given. Experiments with these "rotating filter dosimeters" were conducted in atmospheres radiologically dominated by 222Rn progeny. The comparison between the results obtained by the proposed method and those given by simultaneously conducted series of instantaneous grab-sampling measurements support the conclusion that the method works for 222Rn progeny. The method can be experimentally extended for 220Rn progeny as well as for unattached fractions. PMID:8387983

  10. A novel approach for long-term determination of indoor 222Rn progeny equilibrium factor using nuclear track detectors

    NASA Astrophysics Data System (ADS)

    Amgarou, K.; Font, Ll.; Baixeras, C.

    2003-06-01

    A detailed study of the measurement principles of airborne 222Rn decay products by means of nuclear track detectors (NTDs), taking into account the range of variation of the parameters influencing their concentration indoors, has shown that it is not possible for the existing methods to obtain the associated long-term equilibrium factor with an appropriate accuracy. For this reason, we have established a novel approach based on the new concept of reduced equilibrium factor, which can be obtained from the only measurement of airborne 222Rn and its α-emitter daughter ( 218Po and 214Po) concentrations using a passive, integrating and multi-component system of NTDs. We have found that the equilibrium factor has a linear dependence on the reduced equilibrium factor regardless the values taken for the rates of ventilation, of aerosol attachment and of surface deposition. By using well-controlled exposures in a reference laboratory, we have shown that the equilibrium factor values determined with our system agree with those obtained by active monitors. Finally, as a pilot test, several dosimeters were exposed in an inhabited Swedish single-family house. The results of this exposure suggest the usefulness of this method to perform routine surveys in private homes and in workplaces in order to estimate the annual effective dose received by the general public and the workers due to the presence of 222Rn daughters.

  11. Occurrence of {sup 222}Rn in irrigation water from Wadi Al-Rummah Qassim province, Saudi Arabia

    SciTech Connect

    El-Taher, Atef; Alashrah, Saleh

    2015-08-28

    Naturally accruing radioactive materials in the environment have received attention since they may be present in high level and pose risk to human health. The present work deals with measuring of {sup 222}Rn in irrigation water samples from Wadi Al-Rummah, Qassim province, in central of Saudi Arabia. {sup 222}Rn concentrations were measured by RAD7. It was found that the concentration of {sup 222}Rn ranged from 2.1 ± 1.2 to 7.2 ± 1.5 BqL{sup −1}. These values are below 11.1 BqL{sup −1} the maximum contamination level recommended from the U.S. Environmental Protection Agency. The calculated annual effective dose (AED) ranging from 7.5 to 26.1 µSv/y. It was evident that the total annual effective dose resulting from radon in irrigation groundwater in Wadi Al-Rummah in Qassim area were significantly lower than the recommended limit 1 mSv/y for the public.

  12. Inhalation exposures due to radon and thoron ((222)Rn and (220)Rn): Do they differ in high and normal background radiation areas in India?

    PubMed

    Mishra, Rosaline; Sapra, B K; Prajith, R; Rout, R P; Jalaluddin, S; Mayya, Y S

    2015-09-01

    In India, High Background Radiation Areas (HBRAs) due to enhanced levels of naturally occurring radionuclides in soil (thorium and, to a lesser extent, uranium), are located along some parts of the coastal tracts viz. the coastal belt of Kerala, Tamilnadu and Odisha. It is conjectured that these deposits will result in higher emissions of radon isotopes ((222)Rn and (220)Rn) and their daughter products as compared to Normal Background Radiation Areas (NBRAs). While the annual external dose rates contributed by gamma radiations in these areas are about 5-10 times higher, the extent of increase in the inhalation dose rates attributable to (222)Rn and (220)Rn and their decay products is not well quantified. Towards this, systematic indoor surveys were conducted wherein simultaneous measurements of time integrated (222)Rn and (220)Rn gas and their decay product concentrations was carried out in around 800 houses in the HBRAs of Kerala and Odisha to estimate the inhalation doses. All gas measurements were carried out using pin-hole cup dosimeters while the progeny measurements were with samplers and systems based on the Direct radon/thoron Progeny sensors (DRPS/DTPS). To corroborate these passive measurements of decay products concentrations, active sampling was also carried out in a few houses. The results of the surveys provide a strong evidence to conclude that the inhalation doses due to (222)Rn and (220)Rn gas and their decay products in these HBRAs are in the same range as observed in the NBRAs in India. PMID:26065929

  13. Seasonal variation of N2O emissions in France inferred from atmospheric N2O and 222Rn measurements

    NASA Astrophysics Data System (ADS)

    Lopez, M.; Schmidt, M.; Yver, C.; Messager, C.; Worthy, D.; Kazan, V.; Ramonet, M.; Bousquet, P.; Ciais, P.

    2012-07-01

    Nitrous oxide (N2O) concentrations and 222Rn activities are measured semi-continuously at three stations in France: Gif-sur-Yvette (a semi-urban station near Paris), Trainou tower (a rural station) and Puy-de-Dôme (a mountain site). From 2002 to 2011, we have found a mean rate of N2O increase of 0.7 pbb a-1. The analysis of the mean diurnal N2O and 222Rn cycles shows maximum variabilities at the semi-urban site of Gif-sur-Yvette (0.96 ppb for N2O and 2 Bq m-3 for 222Rn) compared to the rural site of Trainou tower (0.32 ppb for N2O and 1.3 Bq m-3 for 222Rn). The use of 222Rn as a tracer for vertical mixing and atmospheric transport, combined with the semi-continuous N2O measurements, allows estimation of N2O emissions by applying the Radon-Tracer-Method. Mean N2O emissions values between 0.34 ± 0.12 and 0.51 ± 0.18 g(N2O) m-2 a-1 and 0.52 ± 0.18 g(N2O) m-2 a-1were estimated in the catchment area of Gif-sur-Yvette and Trainou, respectively. The mean annual N2O fluxes at Gif-sur-Yvette station correlate well with annual precipitation. A 25% increase in precipitation corresponds to a 32% increase in N2O flux. The N2O fluxes calculated with the Radon-Tracer-Method show a seasonal cycle, which indicates a strong contribution from the agricultural source, with the application of fertilizers in the early spring inducing a strong increase in N2O emissions. Finally, the results of the Radon-Tracer-Method agree well with the national and global emission inventories, accounting for the uncertainties of both methods.

  14. Removal of {sup 222}Rn daughters from metal surfaces

    SciTech Connect

    Zuzel, G.; Wojcik, M.; Majorovits, B.; Lampert, M. O.; Wendling, P.

    2015-08-17

    Removal of the long-lived {sup 222}Rn daughters ({sup 210}Pb, {sup 210}Bi and {sup 210}Po) from copper, stainless steel and germanium surfaces was investigated. As cleaning techniques etching and electro-polishing was applied to samples in a form of discs exposed earlier to a strong radon source. Reduction of the {sup 210}Pb activity was tested using a HPGe spectrometer, for {sup 210}Bi a beta spectrometer and for {sup 210}Po an alpha spectrometer was used. According to the conducted measurements electro-polishing was always more efficient compared to etching and in case of copper the activity reduction factors for {sup 210}Pb, {sup 210}Bi and {sup 210}Po were between 200 and 400. Etching does not remove {sup 210}Po from copper but works very efficiently from germanium. Results obtained for {sup 210}Pb and {sup 210}Bi for etched stainless steel were worse but still slightly better than those achieved for copper.

  15. 222Rn+220Rn monitoring by alpha spectrometry.

    PubMed

    Buompane, R; Roca, V; Sabbarese, C; Pugliese, M; Quarto, M; Mattone, C

    2014-07-01

    Controlled 222Rn+220Rn mixed atmospheres have been realised introducing calibrated sources in a stainless steel chamber. An electrostatic alpha monitor internal to the chamber has been used for an accurate discrimination of alpha peaks due to the products of the two isotopes. In the chamber, different specific activities are achieved in order to test the response of the internal reference instrument and to evaluate the possible interferences due to contemporary presence of both radon isotopes. Results show that: (i) the atmospheres are very stable, (ii) the monitor is adequate for their control because the various alpha lines are well evaluated and (iii) using Tyvek® filter, the efficiency of monitor is stable and constant vs. activity. PMID:24723194

  16. Removal of 222Rn daughters from metal surfaces

    NASA Astrophysics Data System (ADS)

    Zuzel, G.; Wojcik, M.; Majorovits, B.; Lampert, M. O.; Wendling, P.

    2015-08-01

    Removal of the long-lived 222Rn daughters (210Pb, 210Bi and 210Po) from copper, stainless steel and germanium surfaces was investigated. As cleaning techniques etching and electro-polishing was applied to samples in a form of discs exposed earlier to a strong radon source. Reduction of the 210Pb activity was tested using a HPGe spectrometer, for 210Bi a beta spectrometer and for 210Po an alpha spectrometer was used. According to the conducted measurements electro-polishing was always more efficient compared to etching and in case of copper the activity reduction factors for 210Pb, 210Bi and 210Po were between 200 and 400. Etching does not remove 210Po from copper but works very efficiently from germanium. Results obtained for 210Pb and 210Bi for etched stainless steel were worse but still slightly better than those achieved for copper.

  17. [sup 222]Rn dosimetry in the dog lung

    SciTech Connect

    Harley, N.H.; Meyers, O.A.; Robbins, E.S.

    1991-01-01

    The alpha dose to cells in bronchial airways in the beagle dog during historical exposures to [sup 222]Rn decay products is calculated using updated information on airway morphometry, call nucleus depth, mucus thickness, physical dosimetry and atmospheric characteristics. The alpha dose per unit exposure to basal call nuclei in the upper airways ranges from 2 to 7 mGy WLM[sup [minus]1] (excluding the trachea) depending upon the exposure protocol used. The dose to alveolar tissue is 3 mGy WLM[sup [minus]1]. In the human lung, the dose factor for the bronchial airways is 9 mGy WLM[sub [minus]1] and for the pulmonary parenchyma 0.5 mGy WLM[sup [minus]1] The human tumors appear primarily in the first few branching airway generations while the only tumors observed in the animals were in the bronchioloalveolar region suggesting a difference in cell sensitivity to alpha radiation.

  18. {sup 222}Rn dosimetry in the dog lung

    SciTech Connect

    Harley, N.H.; Meyers, O.A.; Robbins, E.S.

    1991-12-31

    The alpha dose to cells in bronchial airways in the beagle dog during historical exposures to {sup 222}Rn decay products is calculated using updated information on airway morphometry, call nucleus depth, mucus thickness, physical dosimetry and atmospheric characteristics. The alpha dose per unit exposure to basal call nuclei in the upper airways ranges from 2 to 7 mGy WLM{sup {minus}1} (excluding the trachea) depending upon the exposure protocol used. The dose to alveolar tissue is 3 mGy WLM{sup {minus}1}. In the human lung, the dose factor for the bronchial airways is 9 mGy WLM{sub {minus}1} and for the pulmonary parenchyma 0.5 mGy WLM{sup {minus}1} The human tumors appear primarily in the first few branching airway generations while the only tumors observed in the animals were in the bronchioloalveolar region suggesting a difference in cell sensitivity to alpha radiation.

  19. Radionuclide content of and 222Rn emanation from building materials made from phosphate industry waste products.

    PubMed

    Paredes, C H; Kessler, W V; Landolt, R R; Ziemer, P L; Paustenbach, D J

    1987-07-01

    The radionuclide content and 222Rn emanation coefficients of selected construction materials were determined. The materials were analyzed for 226Ra, 228Ra and 40K by gamma-ray spectrometry. Mineral wool insulation, which is made from Tennessee phosphate slag, and commonly used insulation, which is made from blast furnace slag, had similar concentrations of these radionuclides. Concrete blocks made with phosphate slag had enhanced 226Ra and 228Ra contents when compared to ordinary concrete block. The mineral wool insulation materials which were examined had emanation coefficients that were a few (2-6) times 10(-3). All other materials had emanation coefficients that ranged from 6 X 10(-4) to 4 X 10(-2). PMID:3597095

  20. Measurement of liquid scintillation sources of (210)Pb obtained from (222)Rn decay.

    PubMed

    Antohe, A; Sahagia, M; Luca, A; Ioan, M-R; Ivan, C

    2016-03-01

    Liquid scintillation samples were filled with (222)Rn and the activity was measured with good precision after reaching the secular equilibrium with the progeny (218)Po, (214)Pb, (214)Bi and (214)Po. After decay of most of (222)Rn activity, the samples contain (210)Pb and progeny. The activities of (210)Pb and progeny can be calculated as a function of time using the initial (222)Rn activity. The samples were measured in a TDCR counter and the experimentally determined counting efficiencies are in accordance with previously published results. PMID:26725538

  1. Estimate of the annual per capita surplus dose due to the elevated indoor exposure to 222Rn progeny caused by the use of slag and spoil of uranium rich coal for building purposes in Ajka Town, Hungary.

    PubMed

    Papp, Z

    1998-03-01

    Ajka is a mining and industrial town in Hungary. Brown coal rich in uranium (300 to 900 Bq kg(-1)) has been mined by the town since 1865. Slag and spoil of the coal were frequently used in the town for building purposes before 1960. Screening measurements of 222Rn progeny in indoor air were performed in 86 Ajka buildings. Elevated 222Rn progeny levels were found in houses that used the above by-products as building materials or foundations. Annual per capita surplus effective doses due to the exposure to elevated 222Rn progeny levels were estimated from the results of the screening measurements. The possibility of estimating the mean of the annual averages of 222Rn or 222Rn progeny concentration for a group of houses from the results of screening measurements is discussed in detail. The estimated annual surplus dose is 0.64 mSv for the population of the whole town and 1.86 mSv for the 7,000 occupants of family houses built before 1960. PMID:9482606

  2. Intrinsic vs. spurious long-range memory in high-frequency records of environmental radioactivity - Critical re-assessment and application to indoor 222Rn concentrations from Coimbra, Portugal

    NASA Astrophysics Data System (ADS)

    Donner, Reik V.; Potirakis, Stelios M.; Barbosa, Susana M.; Matos, Jose A. O.

    2015-04-01

    The presence or absence of long-range correlations in environmental radioactivity fluctuations has recently attracted considerable interest. Among a multiplicity of practically relevant applications, identifying and disentangling the environmental factors controlling the variable concentrations of the radioactive noble gas Radon is important for estimating its effect on human health and the efficiency of possible measures for reducing the corresponding exposition. In this work, we present a critical re-assessment of a multiplicity of complementary methods that have been previously applied for evaluating the presence of long-range correlations and fractal scaling in environmental Radon variations with a particular focus on the specific properties of the underlying time series. As an illustrative case study, we subsequently re-analyze two high-frequency records of indoor Radon concentrations from Coimbra, Portugal, each of which spans several months of continuous measurements at a high temporal resolution of five minutes. Our results reveal that at the study site, Radon concentrations exhibit complex multi-scale dynamics with qualitatively different properties at different time-scales: (i) essentially white noise in the high-frequency part (up to time-scales of about one hour), (ii) spurious indications of a non-stationary, apparently long-range correlated process (at time scales between hours and one day) arising from marked periodic components probably related to tidal frequencies, and (iii) low-frequency variability indicating a true long-range dependent process, which might be dominated by a response to meteorological drivers. In the presence of such multi-scale variability, common estimators of long-range memory in time series are necessarily prone to fail if applied to the raw data without previous separation of time-scales with qualitatively different dynamics. We emphasize that similar properties can be found in other types of geophysical time series (for

  3. Intrinsic vs. spurious long-range memory in high-frequency records of environmental radioactivity. Critical re-assessment and application to indoor 222Rn concentrations from Coimbra, Portugal

    NASA Astrophysics Data System (ADS)

    Donner, R. V.; Potirakis, S. M.; Barbosa, S. M.; Matos, J. A. O.; Pereira, A. J. S. C.; Neves, L. J. P. F.

    2015-05-01

    The presence or absence of long-range correlations in the environmental radioactivity fluctuations has recently attracted considerable interest. Among a multiplicity of practically relevant applications, identifying and disentangling the environmental factors controlling the variable concentrations of the radioactive noble gas radon is important for estimating its effect on human health and the efficiency of possible measures for reducing the corresponding exposition. In this work, we present a critical re-assessment of a multiplicity of complementary methods that have been previously applied for evaluating the presence of long-range correlations and fractal scaling in environmental radon variations with a particular focus on the specific properties of the underlying time series. As an illustrative case study, we subsequently re-analyze two high-frequency records of indoor radon concentrations from Coimbra, Portugal, each of which spans several weeks of continuous measurements at a high temporal resolution of five minutes.Our results reveal that at the study site, radon concentrations exhibit complex multi-scale dynamics with qualitatively different properties at different time-scales: (i) essentially white noise in the high-frequency part (up to time-scales of about one hour), (ii) spurious indications of a non-stationary, apparently long-range correlated process (at time scales between some hours and one day) arising from marked periodic components, and (iii) low-frequency variability indicating a true long-range dependent process. In the presence of such multi-scale variability, common estimators of long-range memory in time series are prone to fail if applied to the raw data without previous separation of time-scales with qualitatively different dynamics.

  4. Radon concentration and working level in the Exploratory Studies Facility (ESF)

    SciTech Connect

    Stiver, J.H.; Tung, Chao-Hsiung

    1995-06-01

    Radon-222 ({sup 222}Rn) and {sup 222}Rn progeny WL monitoring in the Exploratory Studies Facility (ESF) was initiated to support regulatory compliance. Measurements were taken over two periods, in Test Alcove No. 1 of the ESF, about 60 m from the tunnel entrance. For both periods, {sup 222}Rn concentration was less than 10% of the Derived Air Concentration (DAC) set forth in DOE Order 5480.11. Thus, these assessments were sufficient to demonstrate regulatory compliance. Based on these findings, quarterly {sup 222}Rn and {sup 222}Rn progeny monitoring was initiated. Two systems each were employed for {sup 222}Rn and {sup 222}Rn progeny measurement. No significant differences were observed between the respective systems. An interesting finding was that at the time the measurements were taken, barometric pressure appeared to be the predominant factor controlling {sup 222}Rn concentration in the ESF. This was true even during periods of ventilation shutdown.

  5. Estimating the input of submarine groundwater discharge (SGD) and SGD-derived nutrients in Geoje Bay, Korea using (222)Rn-Si mass balance model.

    PubMed

    Hwang, Dong-Woon; Lee, In-Seok; Choi, Minkyu; Kim, Tae-Hoon

    2016-09-15

    In order to evaluate the main source of nutrients for maintaining the high production in shellfish farming bay, we have measured (222)Rn activities and the concentrations of nutrients in stream water, seawater, and coastal groundwater around Geoje Bay, one of the largest cultivation areas of oyster in the southern sea of Korea in April 2013. Using the (222)Rn and Si mass balance model, the residence time of bay seawater was about 5days and the submarine groundwater discharge (SGD) into the bay was estimated to be approximately 1.8×10(6)m(3) d(-1). The SGD-derived nutrient fluxes contributed approximately 54% for DIN, 5% for DIP, and 50% for DSi of total nutrient input entering into the bay. Thus, our results suggest that SGD is the major source of nutrients in Geoje Bay, and SGD-derived nutrients are very important to support the biological production of this shellfish farming bay. PMID:27377001

  6. A novel silicon diffusion membrane method for high-resolution continuous quantification of groundwater-surface water interaction using 222-Rn

    NASA Astrophysics Data System (ADS)

    Hofmann, H.; Gilfedder, B.; Cartwright, I.

    2012-04-01

    222Rn is a naturally produced radioactive isotopic tracer that is commonly used to quantify groundwater discharge to streams, rivers, and wetlands. Traditional sampling and analysis techniques are usually confined to point measurements taken at a specific time. However, it is difficult to constrain short- or medium-term processes occurring at the groundwater-surface water interface using single measurements. Here we describe a method for high-resolution, autonomous, and continuous, measurement of radon in rivers and streams using a silicon diffusion membrane system coupled to a solid-state radon-in-air detector (Durridge RAD7). In this system, water is pumped through a silicon diffusion tube placed inside an outer air circuit tube that is connected to the radon-in-air detector. Radon diffuses from the water into the air loop and is measured by the detector. By optimising the membrane tube length, wall thickness, and water flow rates through the membrane, it was possible to quantify the variability of 222Rn concentrations over timescales of about 3 hours and qualitatively observe changes in as little as 20 minutes. The detection limit for the entire system with 20 minutes counting was 0.018 Bq/L at the 3σ level, which is solely determined by the sensitivity of the detector. Results from the diffusion membrane agree well with conventional measurements of 222Rn made using a RAD7 and an air-water exchanger at both high (20 Bq/L) and low (30 days without requiring attendance. In both cases the system showed variability in 222Rn concentrations that have allowed the short-timescale variations in groundwater inflow and degassing to be constrained and which allow the dynamic processes in these environments to be addressed.

  7. Using (222)Rn as a tracer of geodynamical processes in underground environments.

    PubMed

    Valladares, D L; da Silva, A A R; Lacerda, T; Anjos, R M; Rizzotto, M; Velasco, H; de Rosas, J P; Tognelli, G; Yoshimura, E M; Ayub, J Juri

    2014-01-15

    Radon levels in two old mines in San Luis, Argentina, were measured and analyzed, with the aim to assess the potential use of this radioactive noble gas as a tracer of geological processes in underground environments. La Carolina gold mine and Los Cóndores tungsten mine are today used as tourism mines. CR-39 nuclear track detectors were used for this purpose. Measurements were performed during both winter and summer seasons. The findings show that in these environments, significant radon concentrations are subject to large seasonal fluctuations, due to the strong dependence on natural ventilation with the outside temperature variations. For both mines, higher concentration values of (222)Rn were observed in summer than in winter; with an extreme ratio of 2.5 times between summer and winter seasons for Los Cóndores mine. The pattern of radon transport inside La Carolina mine revealed, contrary to what was believed, that this mine behaves as a system with two entrances located at different levels. However, this feature can only be observed in the winter season, when there is a marked difference between the inside and outside temperatures of the mine. In the case of Los Cóndores mine, the radon concentration pattern distribution is principally established by air current due to chimney-effect in summer and winter seasons. In both cases, the analyses of radon pattern distribution appear as a good method to trace air currents, and then localize unknown ducts, fissures or secondary tunnels in subterranean environments. PMID:24012891

  8. A portable battery-powered continuous airborne {sup 222}Rn sampler

    SciTech Connect

    Scarpitta, S.; Kadnar, M.

    1998-04-01

    The Polyport, designed at the Environmental Measurements Laboratory (EML) for deployment in atmospheric balloons or remote areas, was laboratory and field tested to determine its effectiveness in collecting {sup 222}Rn gas in dry and humid air. Twelve 6-cm long tubes containing 0.4 g of Carboxen{trademark}-564 a hydrophobic beaded carbon molecular sieve (BCMS) material efficiently adsorbs airborne {sup 222}Rn under dynamic sampling conditions of 1--2 hr duration. The exposed sorbent is later weighed for water uptake, transferred and counted in a low background liquid scintillation (LS) counter that can detect alpha and beta emitting {sup 222}Rn progeny with a maximum counting efficiency of 5 cpm per dpm. Each sorbent tube can be gamma counted if it contains sufficient adsorbed {sup 214}Pb and {sup 214}Bi activity. The variables tested were sampling flow rate, temperature, sampling time and relative humidity (RH).

  9. Real-time radon monitoring at Stromboli volcano: influence of environmental parameters on 222Rn degassing

    NASA Astrophysics Data System (ADS)

    Cigolini, C.; Ripepe, M.; Poggi, P.; Laiolo, M.

    2008-12-01

    Two real-time stations for radon monitoring are currently operative at Stromboli volcano. The 222Rn electronic dosimeters are interfaced with an electronic board connected to a radiomodem for wireless data transfer (through a directional antenna) to a receiving station at the volcano observatory (COA). Radon activity data and enviromental parameters (soil temperature and atmospheric pressure) are sampled every 15 minutes and are instantaneously elaborated and transferred via web so that they can be checked in remote. Collected time series show that there is an overall inverse correlation between radon emissions and seasonal temperature variations. Signal processing analysis show that radon emissions in sectors of diffuse degassing are modulated by tidal forces as well. In addition, radon activities recorded at the summit station, located along the summit fracture zone where the gas flux is concentrated, are positively correlated with changes in atmospheric pressure and confirm the occurrence of the 'atmospheric stack effect'. It is not excluded that this process may play an active role in modulating Stromboli explosivity.

  10. Examining the spatial and temporal variation of groundwater inflows to a valley-to-floodplain river using 222Rn, geochemistry and river discharge: the Ovens River, southeast Australia

    NASA Astrophysics Data System (ADS)

    Yu, M. C. L.; Cartwright, I.; Braden, J. L.; de Bree, S. T.

    2013-04-01

    concentrations yield higher estimates of groundwater influxes by up to 2000% in the upper and middle catchments but lower estimates by 50-100% in the lower catchment. Hydrograph separation yields far higher baseflow fluxes than 222Rn activities and Cl concentrations. The high baseflow estimates using Cl concentrations may be due to the lack of distinct difference between groundwater and surface water Cl concentrations. The other mismatches may indicate the input of other sources of water in additional to regional groundwater.

  11. The 222Rn standard system established at IFIN-HH, Romania.

    PubMed

    Sahagia, M; Stanga, D; Wätjen, A C; Luca, A; Cassette, P; Ivan, C; Antohe, A

    2010-01-01

    The paper presents the (222)Rn Standard System realized at the Radionuclide Metrology Laboratory from IFIN-HH, Romania. It contains a Pylon solid (226)Ra source, and a glass circuit for circulation and recovery of (222)Rn in glass ampoules, at the 77K temperature. The radon can be recovered both in ampoules with liquid scintillator (LS), for absolute standardization of (222)Rn by liquid scintillation counting (LSC) (Cassette et al., 2006), and in evacuated ampoules as gas, simultaneously or by the transfer of radon from gas into LS ampoules, in order to establish the traceability chain. The absolute standardization consists in the registration of the double coincidence counting rate in LS, due to the whole sequence of short life components of the (222)Rn chain, in equilibrium conditions. The main correction applied to the measurement results is due to the decay of (214)Po during the extendable dead time of the system. The following procedure was applied to take it into account. The value of the base duration of the dead time was precisely measured and used for the data corrections. The measurements of each source were repeated during a period of several days, and the decay curve parameters were calculated. If the dead time value and the correction formulae, presented throughout the paper, were adequate, then the re-determination of the (222)Rn half life, T(1/2)=(3.8232+/-0.0008) d, using the decay curve of the corrected counting rates should be correct. On the other hand, the effective dead time values obtained by parallel calculations were compared. The paper presents the results obtained in the standardization of several sources, by LSC, and the evaluation of the uncertainties associated to the method. PMID:20022259

  12. (222)Rn activity in groundwater of the St. Lawrence Lowlands, Quebec, eastern Canada: relation with local geology and health hazard.

    PubMed

    Pinti, Daniele L; Retailleau, Sophie; Barnetche, Diogo; Moreira, Floriane; Moritz, Anja M; Larocque, Marie; Gélinas, Yves; Lefebvre, René; Hélie, Jean-François; Valadez, Arisai

    2014-10-01

    One hundred ninety-eight groundwater wells were sampled to measure the (222)Rn activity in the region between Montreal and Quebec City, eastern Canada. The aim of this study was to relate the spatial distribution of (222)Rn activity to the geology and the hydrogeology of the study area and to estimate the potential health risks associated with (222)Rn in the most populated area of the Province of Quebec. Most of the groundwater samples show low (222)Rn activities with a median value of 8.6 Bq/L. Ninety percent of samples show (222)Rn activity lower than 100 Bq/L, the exposure limit in groundwater recommended by the World Health Organization. A few higher (222)Rn activities (up to 310 Bq/L) have been measured in wells from the Appalachian Mountains and from the magmatic intrusion of Mont-Saint-Hilaire, known for its high level of indoor radon. The spatial distribution of (222)Rn activity seems to be related mainly to lithology differences between U-richer metasediments of the Appalachian Mountains and magmatic intrusions and the carbonaceous silty shales of the St. Lawrence Platform. Radon is slightly enriched in sodium-chlorine waters that evolved at contact with clay-rich formations. (226)Ra, the parent element of (222)Rn could be easily adsorbed on clays, creating a favorable environment for the production and release of (222)Rn into groundwater. The contribution of groundwater radon to indoor radon or by ingestion is minimal except for specific areas near Mont-Saint-Hilaire or in the Appalachian Mountains where this contribution could reach 45% of the total radioactive annual dose. PMID:24973780

  13. Behavior of the 222Rn daughters on copper surfaces during cleaning

    SciTech Connect

    Wojcik, Marcin; Zuzel, Grzegorz

    2007-03-28

    Removal of the long-living 222Rn daughters (210Pb, 210Bi and 210Po) from the copper surface has been investigated. Different methods, like chemical etching and electropolishing, were applied to discs exposed earlier to a strong radon source. A long exposure assured effective accumulation of the 222Rn progenies on the copper surface. Cleaning efficiency for 210Pb was tested using a HPGe spectrometer, for 210Bi a beta spectrometer and for 210Po an alpha spectrometer were used. According to the conducted measurements electropolishing removes very effectively all the isotopes, while etching works only for lead and bismuth, for polonium the cleaning effect is practically negligible. Most probable 210Po is re-deposited on the treated surface.

  14. Examining the spatial and temporal variation of groundwater inflows to a valley-to-floodplain river using 222Rn, geochemistry and river discharge: the Ovens River, southeast Australia

    NASA Astrophysics Data System (ADS)

    Yu, M. C. L.; Cartwright, I.; Braden, J. L.; de Bree, S. T.

    2013-12-01

    Radon (222Rn) and major ion geochemistry were used to define and quantify the catchment-scale groundwater-surface water interactions along the Ovens River in the southeast Murray-Darling Basin, Victoria, Australia, between September 2009 and October 2011. The Ovens River is characterized by the transition from a single channel within a mountain valley in the upper catchment to a multi-channel meandering river on flat alluvial plains in the lower catchment. Overall, the Ovens River is dominated by gaining reaches, receiving groundwater from both alluvial and basement aquifers. The distribution of gaining and losing reaches is governed by catchment morphology and lithology. In the upper catchment, rapid groundwater recharge through the permeable aquifers increases the water table. The rising water table, referred to as hydraulic loading, increases the hydraulic head gradient toward the river and hence causes high baseflow to the river during wet (high flow) periods. In the lower catchment, lower rainfall and finer-gained sediments reduce the magnitude and variability of hydraulic gradient between the aquifer and the river, producing lower but more constant groundwater inflows. The water table in the lower reaches has a shallow gradient, and small changes in river height or groundwater level can result in fluctuating gaining and losing behaviour. The middle catchment represents a transition in river-aquifer interactions from the upper to the lower catchment. High baseflow in some parts of the middle and lower catchments is caused by groundwater flowing over basement highs. Mass balance calculations based on 222Rn activities indicate that groundwater inflows are 2 to 17% of total flow with higher inflows occurring during high flow periods. In comparison to 222Rn activities, estimates of groundwater inflows from Cl concentrations are higher by up to 2000% in the upper and middle catchment but lower by 50 to 100% in the lower catchment. The high baseflow estimates using

  15. A novel silicon diffusion membrane method for high-resolution continuous quantification of groundwater-surface water interaction using 222Rn

    NASA Astrophysics Data System (ADS)

    Cartwright, I.; Hofmann, H.; Gilfedder, B.

    2011-12-01

    222Rn is a naturally produced radioactive isotopic tracer that is commonly used to quantify groundwater discharge to streams, rivers, and wetlands. Traditional sampling and analysis techniques are usually confined to point measurements taken at a specific time. However, it is difficult to constrain short- or medium-term processes occurring at the groundwater-surface water interface using single measurements. Here we describe a method for high-resolution, autonomous, and continuous, measurement of radon in rivers and streams using a silicon diffusion membrane system coupled to a solid state radon-in-air detector (Durridge RAD7). In this system, water is pumped through a silicon diffusion tube placed inside an outer air circuit tube that is connected to the radon-in-air detector. Radon diffuses from the water into the air loop and is measured by the detector. By optimising the membrane tube length, wall thickness, and water flow rates through the membrane, it was possible to quantify the variability of 222Rn concentrations over timescales of about 3 hours and qualitatively observe changes in as little as 20 minutes. The detection limit for the entire system with 20 minutes counting was 0.018 Bq/L at the 3σ level, which is solely determined by the sensitivity of the detector. Results from the diffusion membrane agree well with conventional measurements of 222Rn made using a RAD7 and an air-water exchanger at both high (20 Bq/L) and low (<1 Bq/L) concentrations. The silicon membrane system is suitable for continuous and autonomous monitoring of groundwater-surface water interactions on hourly to monthly times scales. Unlike unshielded diffusion membranes (such as the Membrana system), the system is not prone to clogging with sediment or biofilms even in turbid water; additionally, the silicon membrane is flexible and can be coiled for installation at sites where space is restricted. While the response times are slower than air-water exchangers, the silicon membrane

  16. An improved sup 222 Rn canister using a two-stage charcoal system

    SciTech Connect

    Scarpitta, S.C.; Harley, N.H. )

    1991-02-01

    A prototype for an improved passive {sup 222}Rn canister (R-Canister) was designed and compared to conventional charcoal canisters for its adsorptive and desorptive characteristics following exposures to {sup 222}Rn at 23{degrees}C in the presence of water vapor. The R-Canister, containing a two-stage charcoal system, minimizes the adverse effects of water vapor by maintaining the amount of adsorbed water vapor in the primary Rn adsorbent below the break-point of the charcoal. This is achieved by the placement of a desiccant charcoal cartridge 6 cm above the primary Rn adsorbent. The optimal bed depth of the primary adsorbent, determined from a diffusion study, was found to be 2.3 cm. The measured value for the effective diffusion coefficient of RN in a peat-based charcoal at 15% humidity and 25{degrees}C is 7.97 x 10(-10) m2 s-1. Exposures to 70% humidity for 7 d increased the buildup time-constant of Rn in the R-Canisters by 33% as compared to R-Canisters exposed to 15% humidity. At relative humidities ranging from 15-70%, the {sup 222}Rn buildup time-constant of the R-Canister ranged from 43-94 h, whereas the desorption time-constant ranged from 46-64 h. Typical buildup time-constants and desorption time-constants for conventional fully-opened charcoal canisters currently in field use ranged from 30-43 h and 17-29 h, respectively, over the same range of humidities.

  17. Removal of the long-lived {sup 222}Rn daughters from steel and germanium surfaces

    SciTech Connect

    Wojcik, Marcin; Zuzel, Grzegorz; Majorovits, Bela

    2011-04-27

    Removal of the long-lived {sup 222}Rn daughters ({sup 210}Pb, {sup 210}Bi and {sup 210}Po) from stainless steel and germanium surfaces was investigated. As cleaning technique etching was applied to samples in a form of discs exposed earlier to a strong radon source. Reduction of the {sup 210}Pb activity was tested using a HPGe spectrometer, for {sup 210}Bi a beta spectrometer and for {sup 210}Po an alpha spectrometer was used. According to the conducted measurements all the isotopes were removed very efficiently from germanium. Results obtained for stainless steel were worse but still better than those achieved for copper.

  18. Diurnal Variation in Radon Concentration and Mixing-Layer Depths

    NASA Astrophysics Data System (ADS)

    Kataoka, Toshio

    Variation of 222Rn, its short-lived daughters and 212Pb concentrations in the atmosphere, and conditions of the lower atmosphere were observed simultaneously at Kamisaibara Village in Japan. The variation of 222Rn concentration and the ratio of the concentrations of 212Pb and the short-lived daughters of 222Rn during nighttime is explained by sodar echoes and temperature profiles obtained by an instrumented tethered balloon. Depths of the convective mixing layer estimated using the 222Rn concentration, using the surface sensible heat flux, and obtained by low-level sondes are compared and found to be in approximate agreement.

  19. Radon levels and doses in dwellings in two villages in Kosovo, affected by depleted uranium.

    PubMed

    Nafezi, G; Gregoric, A; Vaupotic, J; Bahtijari, M; Kuqali, M

    2014-01-01

    The radon ((222)Rn) activity concentration in 15 dwellings in the Planej village and 10 dwellings in the Gorozhup village has been measured with the aim to complement the national radon survey and to compare the results of two different measurement techniques. The radon concentration has been measured in winter and spring using alpha scintillation cells and in winter, spring and summer by exposing solid-state nuclear track detectors. Both methods gave similar results. Radon concentrations in both villages were similar, ranging from 82 to 432 Bq m(-3); the value of 400 Bq m(-3) was exceeded only in two dwellings. The resulting annual effective doses ranged from 1.78 to 6.40 mSv, with the average values of 3.28 mSv in the Planej village and 3.87 mSv in the Gorozhup village. PMID:24051175

  20. Modeling and experimental validation of the dispersion of 222Rn released from a uranium mine ventilation shaft

    NASA Astrophysics Data System (ADS)

    Xie, Dong; Wang, Hanqing; Kearfott, Kimberlee J.

    2012-12-01

    Radon (222Rn) found in uranium mine shaft ventilation exhaust gases could pose hazards to the surrounding environment and the public by virtue of its progeny. Radon migration under complex terrain is complicated by pollution source characteristics, geographical features of the dispersion region, meteorological conditions and precipitation. Fluid dynamics computations of 222Rn dispersion are performed for uranium mine shaft exhausts for complex models of the actual physical terrain corresponding to a mine in the Jiangxi Province of China. The eight cases studied included a ventilation shaft source, four downwind velocities (0.5, 1.0, 2.0, 4.0 m s-1) and two underlying surface roughness characteristics (0.1 m, 1.0 m). 222Rn distributions in the vicinity of uranium mine ventilation shaft are computed and compared with field measurements.

  1. PSA discriminator influence on (222)Rn efficiency detection in waters by liquid scintillation counting.

    PubMed

    Stojković, Ivana; Todorović, Nataša; Nikolov, Jovana; Tenjović, Branislava

    2016-06-01

    A procedure for the (222)Rn determination in aqueous samples using liquid scintillation counting (LSC) was evaluated and optimized. Measurements were performed by ultra-low background spectrometer Quantulus 1220™ equipped with PSA (Pulse Shape Analysis) circuit which discriminates alpha/beta spectra. Since calibration procedure is carried out with (226)Ra standard, which has both alpha and beta progenies, it is clear that PSA discriminator has vital importance in order to provide precise spectra separation. Improvement of calibration procedure was done through investigation of PSA discriminator level and, consequentially, the activity of (226)Ra calibration standard influence on (222)Rn efficiency detection. Quench effects on generated spectra i.e. determination of radon efficiency detection were also investigated with quench calibration curve obtained. Radon determination in waters based on modified procedure according to the activity of (226)Ra standard used, dependent on PSA setup, was evaluated with prepared (226)Ra solution samples and drinking water samples with assessment of measurement uncertainty variation included. PMID:27016710

  2. Assessment of (222)Rn emanation from ore body and backfill tailings in low-grade underground uranium mine.

    PubMed

    Mishra, Devi Prasad; Sahu, Patitapaban; Panigrahi, Durga Charan; Jha, Vivekanand; Patnaik, R Lokeswara

    2014-02-01

    This paper presents a comparative study of (222)Rn emanation from the ore and backfill tailings in an underground uranium mine located at Jaduguda, India. The effects of surface area, porosity, (226)Ra and moisture contents on (222)Rn emanation rate were examined. The study revealed that the bulk porosity of backfill tailings is more than two orders of magnitude than that of the ore. The geometric mean radon emanation rates from the ore body and backfill tailings were found to be 10.01 × 10(-3) and 1.03 Bq m(-2) s(-1), respectively. Significant positive linear correlations between (222)Rn emanation rate and the (226)Ra content of ore and tailings were observed. For normalised (226)Ra content, the (222)Rn emanation rate from tailings was found to be 283 times higher than the ore due to higher bulk porosity and surface area. The relative radon emanation from the tailings with moisture fraction of 0.14 was found to be 2.4 times higher than the oven-dried tailings. The study suggested that the mill tailings used as a backfill material significantly contributes to radon emanation as compared to the ore body itself and the (226)Ra content and bulk porosity are the dominant factors for radon emanation into the mine atmosphere. PMID:24057960

  3. Bronchial dysplasia induced by radiation in miners exposed to 222Rn progeny.

    PubMed Central

    Michaylov, M A; Pressyanov, D S; Kalinov, K B

    1995-01-01

    OBJECTIVES--To investigate whether sputum cytology can be used to monitor epithelial cell changes in groups at high risk of lung cancer from exposure to radiation. METHODS--Dysplasia of bronchial cells was investigated by means of sputum cytology in a group of 434 underground miners. 100 of them were not exposed, and 334 were exposed to 222Rn progeny at cumulative exposures < 450 working level months. RESULTS--The frequency of dysplasia in the exposed group was significantly higher than that in the not exposed group (P < 0.0001), and an exposure-response relation was found. This relation was different for smokers and non-smokers. CONCLUSIONS--Possibly the frequencies of dysplasia could be used to assess past exposures of groups of miners. This approach could be applied to cases where data on radiation monitoring are not available or are very scarce. Images p82-a PMID:7757171

  4. High-resolution ion pulse ionization chamber with air filling for the 222Rn decays detection

    NASA Astrophysics Data System (ADS)

    Gavrilyuk, Yu. M.; Gangapshev, A. M.; Gezhaev, A. M.; Etezov, R. A.; Kazalov, V. V.; Kuzminov, V. V.; Panasenko, S. I.; Ratkevich, S. S.; Tekueva, D. A.; Yakimenko, S. P.

    2015-11-01

    The construction and characteristics of the cylindrical ion pulse ionization chamber (CIPIC) with a working volume of 3.2 L are described. The chamber is intended to register α-particles from the 222Rn and its daughter's decays in the filled air sample. The detector is less sensitive to electromagnetic pick-ups and mechanical noises. The digital pulse processing method is proposed to improve the energy resolution of the ion pulse ionization chamber. An energy resolution of 1.6% has been achieved for the 5.49 MeV α-line. The dependence of the energy resolution on high voltage and working media pressure has been investigated and the results are presented.

  5. Removal of the long-lived 222Rn daughters from copper and stainless steel surfaces

    NASA Astrophysics Data System (ADS)

    Zuzel, G.; Wójcik, M.

    2012-06-01

    Removal of the long-lived 222Rn daughters from copper and stainless steel surfaces was investigated. Etching and electropolishing were applied to discs exposed earlier to a strong radon source for 210Pb, 210Bi and 210Po deposition. Cleaning efficiency for 210Pb was tested with a n-type high purity germanium spectrometer, for 210Bi a beta spectrometer and for 210Po an alpha spectrometer was used. According to the performed measurements electropolishing removes very effectively all the isotopes from copper and stainless steel. Copper etching reduces efficiently lead and bismuth however for polonium the effect is negligible because of its fast re-deposition. For stainless steel, etching is much more effective compared to copper and it also works for 210Po.

  6. Removal of long-lived 222Rn daughters by electropolishing thin layers of stainless steel

    NASA Astrophysics Data System (ADS)

    Schnee, R. W.; Bowles, M. A.; Bunker, R.; McCabe, K.; White, J.; Cushman, P.; Pepin, M.; Guiseppe, V. E.

    2013-08-01

    Long-lived alpha and beta emitters in the 222Rn decay chain on detector surfaces may be the limiting background in many experiments attempting to detect dark matter or neutrinoless double beta decay. Removal of tens of microns of material via electropolishing has been shown to be effective at removing radon daughters implanted into material surfaces. Some applications, however, require the removal of uniform and significantly smaller thicknesses. Here, we demonstrate that electropolishing < 1 μm from stainless-steel plates reduces the contamination efficiently, by a factor > 100. Examination of electropolished wires with a scanning electron microscope confirms that the thickness removed is reproducible and reasonably uniform. Together, these tests demonstrate the effectiveness of removal of radon daughters for a proposed low-radiation, multi-wire proportional chamber (the BetaCage), without compromising the screener's energy resolution. More generally, electropolishing thin layers of stainless steel may effectively remove radon daughters without compromising precision-machined parts.

  7. Radon (222Rn) in ground water of fractured rocks: a diffusion/ion exchange model.

    PubMed

    Wood, Warren W; Kraemer, Thomas F; Shapiro, Allen

    2004-01-01

    Ground waters from fractured igneous and high-grade sialic metamorphic rocks frequently have elevated activity of dissolved radon (222Rn). A chemically based model is proposed whereby radium (226Ra) from the decay of uranium (238U) diffuses through the primary porosity of the rock to the water-transmitting fracture where it is sorbed on weathering products. Sorption of 226Ra on the fracture surface maintains an activity gradient in the rock matrix, ensuring a continuous supply of 226Ra to fracture surfaces. As a result of the relatively long half-life of 226Ra (1601 years), significant activity can accumulate on fracture surfaces. The proximity of this sorbed 226Ra to the active ground water flow system allows its decay progeny 222Rn to enter directly into the water. Laboratory analyses of primary porosity and diffusion coefficients of the rock matrix, radon emanation, and ion exchange at fracture surfaces are consistent with the requirements of a diffusion/ion-exchange model. A dipole-brine injection/withdrawal experiment conducted between bedrock boreholes in the high-grade metamorphic and granite rocks at the Hubbard Brook Experimental Forest, Grafton County, New Hampshire, United States (42 degrees 56'N, 71 degrees 43'W) shows a large activity of 226Ra exchanged from fracture surfaces by a magnesium brine. The 226Ra activity removed by the exchange process is 34 times greater than that of 238U activity. These observations are consistent with the diffusion/ion-exchange model. Elutriate isotopic ratios of 223Ra/226Ra and 238U/226Ra are also consistent with the proposed chemically based diffusion/ion-exchange model. PMID:15318778

  8. Quantification of Submarine Groundwater Discharge Using a Radon (222-Rn) Mass Balance and Hydrogeological Modelling

    NASA Astrophysics Data System (ADS)

    Petermann, Eric; Stollberg, Reiner; Scholten, Jan; Knöller, Kay; Schubert, Michael

    2016-04-01

    Apart from river and surface water runoff subsurface discharge of groundwater plays a key role in coastal water and matter budgets. Two major forms of submarine groundwater discharge (SGD) can be distinguished: (i) pure freshwater discharge from continental aquifers that are connected to the coastal sea driven by a positive hydraulic gradient (fresh SGD) and (ii) re-circulation of seawater that has penetrated permeable coastal sediments (re-circulated SGD), e.g. driven by tidal pumping. The localization of SGD zones and the quantification of SGD fluxes is of high interest for coastal water management due to potential threats related to SGD, namely (i) the detrimental impact of discharging nutrient- or contaminant-laden groundwater on coastal seawater quality, an aspect that is of relevance along coastlines which are impacted by agriculture, industry or intense urbanization, and (ii) the loss of freshwater to the ocean, an issue that is of major relevance in all coastal areas with (seasonally) limited freshwater availability. In this work, we discuss estimates for the total (fresh + re-circulated) SGD fluxes derived from a mass balance of the radioactive noble gas radon (222-Rn) with estimates of fresh SGD fluxes derived by hydrogeological modelling. The precision of the mass balance results depends on the adequate determination of the mass balance source and sink terms. These terms are calculated based on field observations of environmental tracers (salinity, δ18O, 222-Rn, 223-Ra, 224-Ra, 226-Ra) in seawater and porewater, as well as on meteorological data. The numerical hydrogeological model estimates groundwater flow based on groundwater monitoring data, river flow data, groundwater recharge estimates, tidal dynamics, and density effects along the freshwater/seawater interface. We compare these two independent methodological approaches of SGD flux estimation, discuss results regarding their relevance for the regional water balance and reason the implications of

  9. Radon (222Rn) in ground water of fractured rocks: A diffusion/ion exchange model

    USGS Publications Warehouse

    Wood, W.W.; Kraemer, T.F.; Shapiro, A.

    2004-01-01

    Ground waters from fractured igneous and high-grade sialic metamorphic rocks frequently have elevated activity of dissolved radon (222Rn). A chemically based model is proposed whereby radium (226Ra) from the decay of uranium (238U) diffuses through the primary porosity of the rock to the water-transmitting fracture where it is sorbed on weathering products. Sorption of 226Ra on the fracture surface maintains an activity gradient in the rock matrix, ensuring a continuous supply of 226Ra to fracture surfaces. As a result of the relatively long half-life of 226Ra (1601 years), significant activity can accumulate on fracture surfaces. The proximity of this sorbed 226Ra to the active ground water flow system allows its decay progeny 222Rn to enter directly into the water. Laboratory analyses of primary porosity and diffusion coefficients of the rock matrix, radon emanation, and ion exchange at fracture surfaces are consistent with the requirements of a diffusion/ion- exchange model. A dipole-brine injection/withdrawal experiment conducted between bedrock boreholes in the high-grade metamorphic and granite rocks at the Hubbard Brook Experimental Forest, Grafton County, New Hampshire, United States (42??56???N, 71??43???W) shows a large activity of 226Ra exchanged from fracture surfaces by a magnesium brine. The 226Ra activity removed by the exchange process is 34 times greater than that of 238U activity. These observations are consistent with the diffusion/ion-exchange model. Elutriate isotopic ratios of 223Ra/226Ra and 238U/226Ra are also consistent with the proposed chemically based diffusion/ion-exchange model.

  10. Measurement of (222)Rn by absorption in plastic scintillators and alpha/beta pulse shape discrimination.

    PubMed

    Mitev, Krasimir K

    2016-04-01

    This work demonstrates that common plastic scintillators like BC-400, EJ-200 and SCSF-81 absorb radon and their scintillation pulse decay times are different for alpha- and beta-particles. This allows the application of pulse shape analysis for separation of the pulses of alpha- and beta-particles emitted by the absorbed radon and its progeny. It is shown that after pulse shape discrimination of beta-particles' pulses, the energy resolution of BC-400 and EJ-200 alpha spectra is sufficient to separate the peaks of (222)Rn, (218)Po and (214)Po and allows (222)Rn measurements that are unaffected by the presence of thoron ((220)Rn) in the environment. The alpha energy resolution of SCSF-81 in the experiments degrades due to imperfect collection of the light emitted inside the scintillating fibers. The experiments with plastic scintillation microspheres (PSM) confirm previous findings of other researchers that PSM have alpha-/beta-discrimination properties and show suitability for radon measurements. The diffusion length of radon in BC-400 and EJ-200 is determined. The pilot experiments show that the plastic scintillators are suitable for radon-in-soil-gas measurements. Overall, the results of this work suggest that it is possible to develop a new type of radon measurement instruments which employ absorption in plastic scintillators, pulse-shape discrimination and analysis of the alpha spectra. Such instruments can be very compact and can perform continuous, real-time radon measurements and thoron detection. They can find applications in various fields from radiation protection to earth sciences. PMID:26851823

  11. Precursory Subsurface 222Rn and 220Rn Degassing Signatures of the 2004 Seismic Crisis at Tenerife, Canary Islands

    NASA Astrophysics Data System (ADS)

    Pérez, Nemesio M.; Hernández, Pedro A.; Padrón, Eleazar; Melián, Gladys; Marrero, Rayco; Padilla, Germán; Barrancos, José; Nolasco, Dácil

    2007-12-01

    Precursory geochemical signatures of radon degassing in the subsurface of the Tenerife Island were observed several months prior to the recent 2004 seismic-volcanic crisis. These premonitory signatures were detected by means of a continuous monitoring of 222Rn and 220Rn activity from a bubbling CO2-rich gas spot located at 2.850 m depth inside a horizontal gallery for groundwater exploitation at Tenerife. Multivariate Regression Analysis (MRA) on time series of the radon activity was applied to eliminate the radon activity fluctuation due to external variables such as barometric pressure, temperature and relative humidity as well as power supply. Material Failure Forecast Method (FFM) was successfully applied to forecast the anomalous seismicity registered in Tenerife Island in 2004. The changes in the 222Rn/220Rn ratio observed after the period of anomalous seismicity might suggest a higher gas flow rate and/or changes in the vertical permeability induced by seismic activity.

  12. Role of gas exchange in the inorganic carbon, oxygen, and /sup 222/Rn budgets of the Amazon River

    SciTech Connect

    Devol, A.H.; Quay, P.D.; Richey, J.E.; Martinelli, L.A.

    1987-01-01

    Dissolved oxygen, /sup 222/Rn, pCO/sub 2/, alkalinity, respiration rate, and discharge have been measured at eight mainstem and seven tributary stations during February-March 1984 in a 1700-km stretch of the Amazon River between Vargem Grande and Obidos in Brazil. Air-water gas exchange rates were estimated two ways: measurements of the flux of /sup 222/Rn int floating domes yielded an average boundary layer thickness of 78..mu..m, and oxygen mass balance calculations resulted in an average of 38..mu..m. Given a boundary layer thickness on the order of 50..mu..m, CO/sub 2/ loss to the atmosphere in the entire reach would have been 37.4 kmol s/sup -1/, which is about equal to the total tributary dissolved inorganic carbon (DIC) input and is about half of the total fluvial DIC input to the section. Thus, CO/sub 2/ evasion is a major component of Amazon River DIC balance. Because gas exchange within the section was rapid relative to water travel time through the section, a quasi-steady state was maintained between respiratory input and evasion of CO/sub 2/. Dissolved /sup 222/Rn activities in the mainstem varied from 3.5 to 8.3 dpm liter/sup -1/ and were always highly supersaturated with respect to the atmosphere. Dissolved radon was also not supported by decay of /sup 222/Ra in the mainstem. A /sup 222/Rn mass balance indicated that direct groundwater input into this stretch of the Amazon mainstem probably accounted for no more than 1% of water discharge.

  13. Precise measurement of the 222Rn half-life: A probe to monitor the stability of radioactivity

    NASA Astrophysics Data System (ADS)

    Bellotti, E.; Broggini, C.; Di Carlo, G.; Laubenstein, M.; Menegazzo, R.

    2015-04-01

    We give the results of a study on the 222Rn decay we performed in the Gran Sasso Laboratory (LNGS) by detecting the gamma rays from the radon progeny. The motivation was to monitor the stability of radioactivity measuring several times per year the half-life of a short lifetime (days) source instead of measuring over a long period the activity of a long lifetime (tens or hundreds of years) source. In particular, we give a possible reason of the large periodical fluctuations in the count rate of the gamma rays due to radon inside a closed canister which has been described in literature and which has been attributed to a possible influence of a component in the solar irradiation affecting the nuclear decay rates. We then provide the result of four half-life measurements we performed underground at LNGS in the period from May 2014 to January 2015 with radon diffused into olive oil. Briefly, we did not measure any change of the 222Rn half-life with a 8 ṡ10-5 precision. Finally, we provide the most precise value for the 222Rn half-life: 3.82146(16)stat(4)syst days.

  14. Monte Carlo simulation of semiconductor detector response to (222)Rn and (220)Rn environments.

    PubMed

    Irlinger, J; Trinkl, S; Wielunksi, M; Tschiersch, J; Rühm, W

    2016-07-01

    A new electronic radon/thoron monitor employing semiconductor detectors based on a passive diffusion chamber design has been recently developed at the Helmholtz Zentrum München (HMGU). This device allows for acquisition of alpha particle energy spectra, in order to distinguish alpha particles originating from radon and radon progeny decays, as well as those originating from thoron and its progeny decays. A Monte-Carlo application is described which uses the Geant4 toolkit to simulate these alpha particle spectra. Reasonable agreement between measured and simulated spectra were obtained for both (220)Rn and (222)Rn, in the energy range between 1 and 10 MeV. Measured calibration factors could be reproduced by the simulation, given the uncertainties involved in the measurement and simulation. The simulated alpha particle spectra can now be used to interpret spectra measured in mixed radon/thoron atmospheres. The results agreed well with measurements performed in both radon and thoron gas environments. It is concluded that the developed simulation allows for an accurate prediction of calibration factors and alpha particle energy spectra. PMID:27074199

  15. Removal of long-lived {sup 222}Rn daughters by electropolishing thin layers of stainless steel

    SciTech Connect

    Schnee, R. W.; Bowles, M. A.; Bunker, R.; McCabe, K.; White, J.; Cushman, P.; Pepin, M.; Guiseppe, V. E.

    2013-08-08

    Long-lived alpha and beta emitters in the {sup 222}Rn decay chain on detector surfaces may be the limiting background in many experiments attempting to detect dark matter or neutrinoless double beta decay. Removal of tens of microns of material via electropolishing has been shown to be effective at removing radon daughters implanted into material surfaces. Some applications, however, require the removal of uniform and significantly smaller thicknesses. Here, we demonstrate that electropolishing < 1 μm from stainless-steel plates reduces the contamination efficiently, by a factor > 100. Examination of electropolished wires with a scanning electron microscope confirms that the thickness removed is reproducible and reasonably uniform. Together, these tests demonstrate the effectiveness of removal of radon daughters for a proposed low-radiation, multi-wire proportional chamber (the BetaCage), without compromising the screener’s energy resolution. More generally, electropolishing thin layers of stainless steel may effectively remove radon daughters without compromising precision-machined parts.

  16. Surface deposition of 222Rn decay products with and without enhanced air motion.

    PubMed

    Rudnick, S N; Maher, E F

    1986-09-01

    The effectiveness of fan-induced air motion in reducing airborne activities of short-lived 222Rn decay products was evaluated in a 78.5-m3 chamber. Observed reductions were as high as 50% for 218Po (RaA), 79% for 214Pb (RaB), and 86% for 214Bi (RaC). Activity measurements of these nuclides on chamber and fan surfaces, along with airborne activities, were used to calculate material balances. Greater than about 90% of deposited activity was found on chamber surfaces, although areal activity densities were higher on fan surfaces. Deposition velocities for decay products not attached to particles were 2.3 mm s-1 when no fans were in operation and 9.2 to 13 mm s-1 when fans were used. Mean boundary layer thicknesses for unattached decay products were estimated to be about four times the recoil distance of a 214Pb atom when no fans were used and about equal to the recoil distance when fans were used. PMID:3744829

  17. Surface deposition of 222Rn decay products with and without enhanced air motion

    SciTech Connect

    Rudnick, S.N.; Maher, E.F.

    1986-09-01

    The effectiveness of fan-induced air motion in reducing airborne activities of short-lived /sup 222/Rn decay products was evaluated in a 78.5-m3 chamber. Observed reductions were as high as 50% for 218Po (RaA), 79% for /sup 214/Pb (RaB), and 86% for /sup 214/Bi (RaC). Activity measurements of these nuclides on chamber and fan surfaces, along with airborne activities, were used to calculate material balances. Greater than about 90% of deposited activity was found on chamber surfaces, although areal activity densities were higher on fan surfaces. Deposition velocities for decay products not attached to particles were 2.3 mm s-1 when no fans were in operation and 9.2 to 13 mm s-1 when fans were used. Mean boundary layer thicknesses for unattached decay products were estimated to be about four times the recoil distance of a /sup 214/Pb atom when no fans were used and about equal to the recoil distance when fans were used.

  18. Measurement of Radon concentration by Xenon gamma-ray spectrometer for seismic monitoring of the Earth

    NASA Astrophysics Data System (ADS)

    Novikov, A.; Ulin, S.; Dmitrenko, V.; Vlasik, K.; Bychkova, O.; Petrenko, D.; Uteshev, Z.; Shustov, A.

    2016-02-01

    A method for earthquake precursors search based on variations of 222Rn concentration determined via intensity measurement of 222Rn daughter nuclei gamma ray emission lines by means of xenon gamma-ray spectrometer is discussed. The equipment description as well as the first experimental data are presented.

  19. Use of 222Rn as natural tracer for LNAPL quantification and recovery efficiency in a crude-oil contaminated aquifer

    NASA Astrophysics Data System (ADS)

    Ponsin, Violaine; Chablais, Amélie; Dumont, Julien; Cardetti, Marc; Radakovitch, Olivier; Höhener, Patrick

    2014-05-01

    In august 2009, five hectares of the pristine gravel aquifer of Crau in southern France were contaminated by 5,100 m3 of crude oil due to the sudden break of a pipeline. The remediation of this site is still ongoing and consists in replacement and off-site disposal of contaminated topsoils, plume management by hydraulic groundwater barriers with re-injection of activated charcoal-treated waters, and dual-phase LNAPL extraction in the source zone. It is anticipated to stop these remediation actions when the rate of hydrocarbon extraction becomes inefficient. The volume of LNAPL is estimated between 100 and 1000 m3. A more accurate estimation is needed for the implementation of natural attenuation once physical treatment is discontinued. 222Rn has been introduced as a natural tracer for the quantification of LNAPL saturation in porous media under natural gradient conditions (Hunkeler et al., 1997; Semprini et al., 2000; Schubert et al., 2007). The objective of this study was to investigate whether 222Rn in groundwater can be used as a tracer for LNAPL quantification at a field site treated by LNAPL removal. To this end, groundwater samples were obtained in pristine monitoring wells from upgradient the contamination using submersible electric pumps, and in LNAPL recovery wells. There, samples were obtained from the tap on the hard PVC tubing used for pumping groundwater to the treatment facility. For 222Rn analysis, flasks of 250 mL were gently filled and were capped thereafter without permitting air bubbles. The flasks were analysed within 6 to 24 hours. The 222Rn activity of groundwater was measured by a Rn detector (RAD7-Durridge, Co. Inc.). The measurements were spaced over more than 15 months in order to account for seasonal changes. Each well was sampled at least 3 times. In pristine groundwater, the radon activity was relatively constant and remained always > 14 Bq/L. The radon activities in the groundwater of source zone wells were also relatively constant and

  20. Removal and deposition efficiencies of the long-lived 222Rn daughters during etching of germanium surfaces

    NASA Astrophysics Data System (ADS)

    Zuzel, G.; Wójcik, M.; Majorovits, B.; Lampert, M. O.; Wendling, P.

    2012-06-01

    Removal and deposition efficiencies of the long-lived 222Rn daughters during etching from and onto surfaces of standard and high purity germanium were investigated. The standard etching procedure of Canberra-France used during production of high purity n-type germanium diodes was applied to germanium discs, which have been exposed earlier to a strong radon source for deposition of its progenies. An uncontaminated sample was etched in a solution containing 210Pb, 210Bi and 210Po. All isotopes were measured before and after etching with appropriate detectors. In contrast to copper and stainless steel, they were removed from germanium very efficiently. However, the reverse process was also observed. Considerable amounts of radioactive lead, bismuth and polonium isotopes present initially in the artificially polluted etchant were transferred to the clean high purity surface during processing of the sample.

  1. Early results of experimental 222Rn flux campaign carried out at a mountain Spanish region and comparison with available radon flux inventories results

    NASA Astrophysics Data System (ADS)

    Nofuentes, Manel; Grossi, Claudia; Morguí, Josep Anton; Curcoll, Roger; Cañas, Lidia; Occhipinti, Paola; Borràs, Silvia; Vazquez, Eusebi; Rodó, Xavier

    2015-04-01

    The atmospheric concentrations of components impacting the greenhouse effect (CO2, CH4, N2O, O3, and aerosols) have increased significantly in the last two centuries, leading to a direct impact on our climate. These climatic changes deeply affect the geochemistry and the dynamics of the main reservoirs such as the atmosphere, the ocean, and the biosphere. Therefore, reductions of the emissions are needed for all four of the most important anthropogenic GHGs: CO2, CH4, N2O and SF6. Particularly, the relative contribution of human induced CH4 in the atmosphere to the total human direct greenhouse effect is about 25%. Furthermore, the CH4 has the shortest lifetime in the atmosphere (about 9 years), so that emissions reduction measures for CH4 will lead to changes in concentration growth rates, or even a concentration decline, at relatively shor time scales. All these reasons make the CH4 an attractive compound to reduce the greenhouse gas emissions. Nowadays, the study and attribution of categories for GHGs sources is carried out by using bottom-up inventories and top-down techniques. The atmospheric concentrations and the fluxes of the noble and radioactive 222Rn gas are widely used for retriving indirectly GHGs fluxes, improving top-down techniques and analysing different type of sources. In the frame of the "Methane exchange between soil and atmosphere over the Iberian Peninsula" (MIP) project (Reference: CGL2013-46186-R, Spanish Ministry of Economy and Competitiveness) four experimental radon flux campaigns are carried out at mountain as well as at coastal Spanish regions using integrated and continuous monitors. The early results of first radon flux campaign carried out at the Gredos and Iruelas climate station (GIC3) of the Catalan Institute of Climate Science (IC3) are presented and compared with available radon flux inventories maps.

  2. Radon concentrations in different types of dwellings in Israel.

    PubMed

    Epstein, L; Koch, J; Riemer, T; Orion, I; Haquin, G

    2014-12-01

    The average radon concentration in Israeli dwellings was assessed by combining the results of a 2006 radon survey in single-family houses with the results of a 2011 radon survey in apartments of multistorey buildings. Both surveys were based on long-term measurements using CR-39 detectors. The survey in multistorey buildings was intended to assess the influence of recent practices in the local building industry on the radon concentrations. These practices include the use of building materials with higher concentrations of the natural radionuclides in the last 20 y than before, as well as the improvement in sealing techniques over that period. Another practice in place since the early 1990 s is the building of a shielded area in every apartment that is known as an RSS (residential secure space). The RSS is a room built from massive concrete walls, floor and ceiling that can be hermetically sealed and is intended to protect its residents from a missile attack. The influence of the above-mentioned features on radon concentrations was estimated by dividing the participating apartments into two groups: apartments in buildings >20 y, built using building materials with low concentrations of the natural radionuclides, regular sealing and without an RSS and apartments in buildings newer than 10 y, built using building materials with higher concentrations of the natural radionuclides, improved sealing and including an RSS. It was found that the average radon concentration in apartments in new buildings was significantly higher than in old buildings and the average radon concentration in single-family houses was significantly higher than in apartments in multistorey buildings. Doses due to indoor radon were estimated on the basis of the updated information included in the 2009 International Commission on Radiological Protection statement on radon. PMID:24381204

  3. Gas exchange dependency on diffusion coefficient: direct /sup 222/Rn and /sup 3/He comparisons in a small lake

    SciTech Connect

    Torgersen, T.; Mathieu, G.; Hesslein, R.H.; Broecker, W.S.

    1982-01-20

    A direct field comparison was conducted to determine the dependency of gas exchange coefficient (k/sub x/) on the diffusion coefficient (D/sub x/). The study also sought to confirm the enhanced vertical exchange properties of limnocorrals and similar enclosures. Gas exchange coefficients for /sup 222/Rn and /sup 3/He were determined in a small northern Ontario lake, using a /sup 226/Ra and /sup 3/H spike to gain the necessary precision. The results indicate that the gas exchange coefficient is functionally dependent on the diffusion coefficient raised to the 1.22/sub -35//sup + > 12/ power (k/sub x/ = f(D/sub x//sup 1.22)), clearly supporting the stagnant film model of gas exchange. Limnocorrals were found to have gas exchange rates up to 1.7 times higher than the whole lake in spite of the observation of more calm surface conditions in the corral than in the open lake. 33 references, 6 figures, 8 tables.

  4. Chemical fertilizers as a source of (238)U, (40)K, (226)Ra, (222)Rn, and trace metal pollutant of the environment in Saudi Arabia.

    PubMed

    Alshahri, Fatimh; Alqahtani, Muna

    2015-06-01

    The specific activities of (238)U, (226)Ra, (40)K, and (222)Rn in chemical fertilizers were measured using gamma ray spectrometer and Cr-39 detector. In this study, 21 chemical fertilizers were collected from Eastern Saudi Arabian markets. The specific activities of (238)U ranged from 23 ± 0.5 to 3900 ± 195 Bq kg(-1); (226)Ra ranged from 5.60 ± 2.80 to 392 ± 18 Bq kg(-1); and (40)K ranged from 18.4 ± 3 to 16,476 ± 820 Bq kg(-1). The radon concentrations and the radon exhalation rates were found to vary from 3.20 ± 1.20 to 1532 ± 160 Bq m(-3) and from 1.60 to 774 mBq m(-2) h(-1), respectively. Radium equivalent activities (Raeq) were calculated for the analyzed samples to assess the radiation hazards arising due to the use of these chemical fertilizers in the agriculture soil. The Raeq for six local samples (nitrogen, phosphorous, and potassium (NPK) and single superphosphate (SSP)) and one imported sample (Sulfate of Potash (SOP)) were greater than the acceptable value 370 Bq kg(-1). The total air absorbed doses rates in air 1 m above the ground (D) were calculated for all samples. All samples, except one imported granule sample diammonium phosphate (DAP), were higher than the estimated average global terrestrial radiation of 55 nGy h(-1). The highest annual effective dose was in triple super phosphate (TSP) fertilizers (2.1 mSv y(-1)). The results show that the local TSP, imported SOP, and local NPK (sample 13) fertilizers were unacceptable for use as fertilizers in agricultural soil. Furthermore, the toxic elements and trace metals (Pb, Cd, Cr, Co, Ni, Hg, and As) were determined using atomic absorption spectrometer. The concentrations of chromium in chemical fertilizers were higher than the global values. PMID:25532871

  5. Using 222Rn as a tracer of geophysical processes in underground environments

    NASA Astrophysics Data System (ADS)

    Lacerda, T.; Anjos, R. M.; Valladares, D. L.; da Silva, A. A. R.; Rizzotto, M.; Velasco, H.; de Rosas, J. P.; Ayub, J. Juri; Yoshimura, E. M.

    2014-11-01

    Radon levels in two old mines in San Luis, Argentina, are reported and analyzed. These mines are today used for touristic visitation. Our goal was to assess the potential use of such radioactive noble gas as tracer of geological processes in underground environments. CR-39 nuclear track detectors were used during the winter and summer seasons. The findings show that the significant radon concentrations reported in this environment are subject to large seasonal modulations, due to the strong dependence of natural ventilation on the variations of outside temperature. The results also indicate that radon pattern distribution appear as a good method to localize unknown ducts, fissures or secondary tunnels in subterranean environments.

  6. Using {sup 222}Rn as a tracer of geophysical processes in underground environments

    SciTech Connect

    Lacerda, T.; Anjos, R. M.; Silva, A. A. R. da; Yoshimura, E. M.

    2014-11-11

    Radon levels in two old mines in San Luis, Argentina, are reported and analyzed. These mines are today used for touristic visitation. Our goal was to assess the potential use of such radioactive noble gas as tracer of geological processes in underground environments. CR-39 nuclear track detectors were used during the winter and summer seasons. The findings show that the significant radon concentrations reported in this environment are subject to large seasonal modulations, due to the strong dependence of natural ventilation on the variations of outside temperature. The results also indicate that radon pattern distribution appear as a good method to localize unknown ducts, fissures or secondary tunnels in subterranean environments.

  7. Radiological impact of phosphogypsum discharged into the Venice lagoon: 222Rn

    NASA Astrophysics Data System (ADS)

    Cantaluppi, C.; Ceccotto, F.; Cianchi, A.; Fasson, A.; Degetto, S.

    2012-04-01

    For about 20 years, between the 60 's and the 80 's of the last century, in the Passo a Campalto area (Lagoon of Venice - Italy) about 400,000 m3 of phosphogypsum (PG) were deposited at the border of the lagoon and next to urban areas without any environmental control. These materials are a by-product formed during the wet processing of phosphate rocks by sulphuric acid and have a significant environmental impact due to their abundance and their chemical-physical and radiochemical characteristics. The PG contains both chemical elements, which are considered dangerous for the ecosystems and natural radionuclides whose concentrations are much higher if compared to those typical for the Earth's crust. These discarded materials caused for many years the dispersion of radionuclides in the environment due to the tidal erosion, the re-suspension of radioactive inhalable dusts, the uncontrolled radon exhalation and the bioaccumulation of some radionuclides in the lagoon environment. After a decision of the appointed authorities, the Venice Water Authority (Ministry of Infrastructure and Transport), planned a permanent safety control of the site resulting in the complete isolation of the entire volume of contaminated materials from the environmental system. The entire project was specific for the particular features of the site and it required the improvement of analytical, sampling and measurement techniques in order to verify the effectiveness of the safety action. The radon assessment, in particular the check of the effectiveness of the inhibition of radon exhalation, is part of a more complex study, covering many other aspects of the management of a permanent disposal; they will be the object of further notes. The ultimate results of this study prove the efficacy of the intervention: radon concentrations in air and exhalation values from the restored area, measured during surveys, have been proved to be well in agreement with those of non contaminated soils.

  8. Measurement of Indoor Radon, Thoron in Dwelling of Delhi, India Using Double Dosimeter Cups with SSNTDS

    NASA Astrophysics Data System (ADS)

    Sharma, Anil; Mahur, Ajay Kumar; Sonkawade, R. G.; Sharma, A. C.

    In present study, Solid State Nuclear Track Detectors (SSNTDS) based twin chamber dosimeter cups were used for estimating Radon (222Rn) and Thoron (220Rn) gas concentration levels in the environmental air of normal background radiation area in thirty one dwellings of Dwarka city of New Delhi, India which were constructed by bricks, cement and concrete. This survey is the very first one carried out in this city and constitutes and preliminary survey to check the methodology and to have a first estimation of the indoor radon impact on Dwarka inhabitants. LR-115 type-II, films were used as detector. In the studied dwellings Radon concentration levels were found to vary from 4.4 ± 1.6 to 29.8 ± 3.8 Bqm-3 whereas thoron concentrations is found to vary from 2.8 ± 0.5 to 13.6 ± 1.7 Bqm-3. The annual effective dose from radon were found to vary from 0.12 to 0.86 mSv whereas from thoron found to vary from 0.01 to 0.07 mSv.

  9. Air-water partitioning of 222Rn and its dependence on water temperature and salinity.

    PubMed

    Schubert, Michael; Paschke, Albrecht; Lieberman, Eric; Burnett, William C

    2012-04-01

    Radon is useful as a tracer of certain geophysical processes in marine and aquatic environments. Recent applications include detection of groundwater discharges into surface waters and assessment of air/sea gas piston velocities. Much of the research performed in the past decade has relied on continuous measurements made in the field using a radon stripping unit connected to a radon-in-air detection system. This approach assumes that chemical equilibrium is attained between the water and gas phases and that the resulting air activity can be multiplied by a partition coefficient to obtain the corresponding radon-in-water activity. We report here the results of a series of laboratory experiments that describes the dependence of the partition coefficient upon both water temperature and salinity. Our results show that the temperature dependence for freshwater closely matches results that were previously available. The salinity effect, however, has largely been ignored and our results show that this can result in an overestimation of radon concentrations, especially in cooler, more saline waters. Related overestimates in typical situations range between 10 (warmer less saline waters) and 20% (cooler, more saline waters). PMID:22385122

  10. The influence of thoron on instruments measuring radon activity concentration.

    PubMed

    Michielsen, N; Bondiguel, S

    2015-11-01

    Thoron, the isotope 220 of radon, is a radionuclide whose concentration may influence the measurement of the activity concentration of (222)Rn in the air. If in the case of continuous and active sampling measuring instruments, using a pump for example, the influence of thoron on radon measurement is obvious and is taken into account in the apparatus, it is often assumed that in the case of a passive sampling, by diffusion through a filter for example, this thoron influence is negligible. This is due to the very short radioactive half-life of thoron, 55.6 s (3.82 d for (222)Rn), and the assumption that the diffusion time of thoron in the detection chamber is long enough beside that of the thoron half-life. The objective of this study is to check whether this assumption is true or not for different kinds of commercial electronic apparatus used to measure radon activity concentration from soil to dwellings. First of all, the devices were calibrated in activity concentration of radon, and then they were exposed to a controlled thoron atmosphere. The experiments concerning the thoron aimed to investigate the sensitivity to thoron in the radon measuring mode of the apparatus. Results of these experiments show that all devices have a very quick answer to thoron atmosphere, even though the sensitivities vary from one instrument to another. Results clearly show that this influence on radon measurement due to the thoron is observed also after the exposition because of the decay of (212)Pb and its progenies. In conclusion, the sensitivity to thoron in the radon measuring mode depends strongly on the type of instruments. The results of the present investigation show that for some apparatus, the influence of thoron cannot be disregarded especially when measuring radon in soil. PMID:25953787

  11. Distance to faults as a proxy for radon gas concentration in dwellings.

    PubMed

    Drolet, Jean-Philippe; Martel, Richard

    2016-02-01

    This research was done to demonstrate the usefulness of the local structural geology characteristics to predict indoor radon concentrations. The presence of geologic faults near dwellings increases the vulnerability of the dwellings to elevated indoor radon by providing favorable pathways from the source uranium-rich bedrock units to the surface. Kruskal-Wallis one-way analyses of variance by ranks were used to determine the distance where faults have statistically significant influence on indoor radon concentrations. The great-circle distance between the 640 spatially referenced basement radon concentration measurements and the nearest fault was calculated using the Haversine formula and the spherical law of cosines. It was shown that dwellings located less than 150 m from a major fault had a higher radon potential. The 150 m threshold was determined using Kruskal-Wallis ANOVA on: (1) all the basement radon measurements dataset and; (2) the basement radon measurements located on uranium-rich bedrock units only. The results indicated that 22.8% of the dwellings located less than 150 m from a fault exceeded the Canadian radon guideline of 200 Bq/m(3) when using all the basement radon measurements dataset. This percentage fell to 15.2% for the dwellings located between 150 m and 700 m from a fault. When using only the basement radon measurements located on uranium-rich bedrock units, these percentages were 30.7% (0-150 m) and 17.5% (150 m-700 m). The assessment and management of risk can be improved where structural geology characteristics base maps are available by using this proxy indicator. PMID:26630035

  12. Concentration and determinants of molds and allergens in indoor air and house dust of French dwellings.

    PubMed

    Dallongeville, Arnaud; Le Cann, Pierre; Zmirou-Navier, Denis; Chevrier, Cécile; Costet, Nathalie; Annesi-Maesano, Isabella; Blanchard, Olivier

    2015-12-01

    Molds and allergens are common indoor biocontaminants. The aims of this study were to assess the concentrations of common molds in indoor air and floor dust and the concentrations of house dust mite, cat and dog allergens in mattress dust in French dwellings, and to assess predictors of these concentrations. A sample of 150 houses in Brittany (western France) was investigated. Airborne Cladosporium and Penicillium were detected in more than 90% of the dwellings, Aspergillus in 46% and Alternaria in only 6% of the housings. Regarding floor dust samples, Cladosporium and Penicillium were detected in 92 and 80% of the housings respectively, Aspergillus in 49% and Alternaria in 14%. House dust mite allergens Der p1 and Der f1 were detected in 90% and 77% of the mattress dust samples respectively and Can f1 and Fel d1 in 37% and 89% of the homes. Airborne and dustborne mold concentrations, although not statistically correlated (except for Aspergillus) shared most of their predictors. Multivariate linear models for mold levels, explaining up to 62% of the variability, showed an influence of the season, of the age of the dwelling, of aeration habits, presence of pets, smoking, signals of dampness, temperature and relative humidity. Allergens in the dust of the mattress were strongly related to the presence of pets and cleaning practices of bedsheets, these factors accounting for 60% of the variability. This study highlights ubiquitous contamination by molds and underlines complex interaction between outdoor and indoor sources and factors. PMID:26094801

  13. Radon concentrations in residential housing in Hiroshima and Nagasaki

    SciTech Connect

    Yonehara, Hidenori; Aoyama, Takashi; Radford, E.P.

    1995-05-01

    A measurement of indoor radon ({sup 222}Rn) concentrations in Hiroshima and Nagasaki was carried out to assess the variability of exposure expected among atomic bomb survivors. Two hundred dwellings, mostly belonging to members of the fixed cohort of atomic bomb survivors under study by the Radiation Effects Research Foundations, were selected for this measurement. The geometric mean values of the radon concentrations for 100 dwellings in Hiroshima and 99 dwellings in Nagasaki measured by Track-Etcho Type SF detectors were 56.8 Bq m{sup {minus}3} and 28.5 Bq m{sup {minus}3}, respectively. No statistically significant difference was observed between lung cancer mortalities in the low-dose range in the two cities. However, apparent values of the mortality rate for low dose range in Hiroshima are consistently greater than those in Nagasaki. The exposure to radon and its progeny and the atomic bomb radiation effect might have some cooperative effects on the lung cancer incidence.

  14. Evaluation of number concentration quantification by single-particle inductively coupled plasma mass spectrometry: microsecond vs. millisecond dwell times.

    PubMed

    Abad-Álvaro, Isabel; Peña-Vázquez, Elena; Bolea, Eduardo; Bermejo-Barrera, Pilar; Castillo, Juan R; Laborda, Francisco

    2016-07-01

    The quality of the quantitative information in single-particle inductively coupled plasma mass spectrometry (SP-ICP-MS) depends directly on the number concentration of the nanoparticles in the sample analyzed, which is proportional to the flux of nanoparticles through the plasma. Particle number concentrations must be selected in accordance with the data acquisition frequency, to control the precision from counting statistics and the bias, which is produced by the occurrence of multiple-particle events recorded as single-particle events. With quadrupole mass spectrometers, the frequency of data acquisition is directly controlled by the dwell time. The effect of dwell times from milli- to microseconds (10 ms, 5 ms, 100 μs, and 50 μs) on the quality of the quantitative data has been studied. Working with dwell times in the millisecond range, precision figures about 5 % were achieved, whereas using microsecond dwell times, the suitable fluxes of nanoparticles are higher and precision was reduced down to 1 %; this was independent of the dwell time selected. Moreover, due to the lower occurrence of multiple-nanoparticle events, linear ranges are wider when dwell times equal to or shorter than 100 μs are used. A calculation tool is provided to determine the optimal concentration for any instrument or experimental conditions selected. On the other hand, the use of dwell times in the microsecond range reduces significantly the contribution of the background and/or the presence of dissolved species, in comparison with the use of millisecond dwell times. Although the use of dwell times equal to or shorter than 100 μs offers improved performance working in single-particle mode, the use of conventional dwell times (3-10 ms) should not be discarded, once their limitations are known. PMID:27086011

  15. Neighborhood Socioeconomic Status Is Associated with Serum Carotenoid Concentrations in Older, Community-Dwelling Women12

    PubMed Central

    Nicklett, Emily J.; Szanton, Sarah; Sun, Kai; Ferrucci, Luigi; Fried, Linda P.; Guralnik, Jack M.; Semba, Richard D.

    2011-01-01

    A high dietary intake of fruit and vegetables has been shown to be protective for health. Neighborhood socioeconomic differences may influence the consumption of carotenoid-rich foods, as indicated by serum carotenoid concentrations. To test this hypothesis, we examined the relationship between neighborhood socioeconomic status (SES) and serum carotenoid concentrations in a population-based sample of community-dwelling women, aged 70–79 y, who participated in the Women’s Health and Aging Study II in Baltimore, Maryland. Neighborhood socioeconomic Z-scores were derived from characteristics of the census block of the participants. Serum carotenoid concentrations were measured at baseline and at 18, 36, 72, 98, and 108 mo follow-up visits. Neighborhood Z-scores were positively associated with serum α-carotene (P = 0.0006), β-carotene (P = 0.07), β-cryptoxanthin (P = 0.03), and lutein+zeaxanthin (P = 0.004) after adjusting for age, race, BMI, smoking, inflammation, and season. There was no significant association between neighborhood Z-score and serum lycopene. Older, community-dwelling women from neighborhoods with lower SES have lower serum carotenoid concentrations, which reflect a lower consumption of carotenoid-rich fresh fruits and vegetables. PMID:21178091

  16. Indoor air radon concentration in schools in Prizren, Kosovo.

    PubMed

    Bahtijari, Meleq; Stegnar, Peter; Shemsidini, Zahadin; Kobal, Ivan; Vaupotic, Janja

    2006-01-01

    Indoor air radon ((222)Rn) concentrations were measured in spring and winter in 30 rooms of 9 elementary schools and 19 rooms of 6 high schools in Prizren, Kosovo, using alpha scintillation cells. Only in three rooms of elementary schools and four rooms of high schools did winter concentrations exceed 400 Bq m(-3). PMID:16766569

  17. Temporal 222Rn distributions to reveal groundwater discharge into desert lakes: Implication of water balance in the Badain Jaran Desert, China

    NASA Astrophysics Data System (ADS)

    Luo, Xin; Jiao, Jiu Jimmy; Wang, Xu-sheng; Liu, Kun

    2016-03-01

    How lake systems are maintained and water is balanced in the lake areas in the Badain Jaran Desert (BJD), northeast of China have been debated for about a decade. In this study, continuous 222Rn measurement is used to quantify groundwater discharge into two representative fresh and brine water lakes in the desert using a steady-state mass-balance model. Two empirical equations are used to calculate atmospheric evasion loss crossing the water-air interface of the lakes. Groundwater discharge rates yielded from the radon mass balance model based on the two empirical equations are well correlated and of almost the same values, confirming the validity of the model. The fresh water and brine lakes have a daily averaged groundwater discharge rate of 7.6 ± 1.7 mm d-1 and 6.4 ± 1.8 mm d-1, respectively. The temporal fluctuations of groundwater discharge show similar patterns to those of the lake water level, suggesting that the lakes are recharged from nearby groundwater. Assuming that all the lakes have the same discharge rate as the two studied lakes, total groundwater discharge into all the lakes in the desert is estimated to be 1.59 × 105 m3 d-1. A conceptual model of water balance within a desert lake catchment is proposed to characterize water behaviors within the catchment. This study sheds lights on the water balance in the BJD and is of significance in sustainable regional water resource utilization in such an ecologically fragile area.

  18. Is thoron a problem in Swedish dwellings? Results of measurements of concentrations of thoron and its progeny.

    PubMed

    Skeppström, K; Wåhlin, E

    2015-11-01

    Long-term measurements of thoron progeny concentrations (equilibrium-equivalent thoron concentration) have been carried out in Swedish dwellings with the aim of investigating if thoron and its progeny pose a health risk. Measurements were performed in 93 houses and 25 apartments. In addition to thoron progeny concentration, thoron gas concentration near the wall surface, ambient dose equivalent rate of gamma radiation and radon gas concentration were also measured. The results show that the mean value of thoron progeny was 2.2 Bq m(-3) in houses and 1.6 Bq m(-3) in apartments. Ten per cent of the dwellings (both houses and apartments) had thoron progeny concentrations exceeding 10 Bq m(-3). Thoron progeny concentration is not significantly different in dwellings built of alum shale-based aerated concrete ('blue concrete') than dwellings built of other construction materials. For the dwellings in this study (not representative of the Swedish population), the mean dose estimated due to exposure to thoron was found to be 0.4 mSv y(-1). PMID:25904697

  19. Prediction of indoor radon concentrations in dwellings in the Oslo region - a model based on geographical information systems

    NASA Astrophysics Data System (ADS)

    Kollerud, R.; Blaasaas, K.; Ganerød, G.; Daviknes, H. K.; Aune, E.; Claussen, B.

    2013-06-01

    The purpose of this study was to develop a method to estimate the radon concentration inside each dwelling in the Oslo region, Norway. The model was based on indoor radon measurements from dwellings at predefined distances from the unmeasured dwellings. The results were evaluated by comparing them with actual indoor measurements, airborne gamma ray spectrometry measurements and bedrock geology. It is the first study to evaluate the reliability between estimated indoor radon in each dwelling with airborne measurements (eK, eTh and eU) and underlying geology around the house in a large population. A total of 28 396 indoor radon measurements showed that 42.2% of the dwellings had a radon value higher than the threshold limit of 100 Bq m-3. 18.9% of the dwellings were above the maximum action level of 200 Bq m-3. A positive correlation was found between indoor radon concentration, bedrock geology and airborne gamma measurements (Pearson correlation: eK: 0.42, eTh: 0.67 and eU: 0.65). Highest correlation was found in areas with alum shale (eU: 0.74). Intraclass Correlation Coefficients (ICCs) showed a good agreement between radon estimates from our method and radon estimates from the regression model with ICC values between 0.54 and 0.67.

  20. [Radon 222Rn in residential buildings of Swieradów Zdrój and Czerniawa Zdrój].

    PubMed

    Pachocki, K A; Gorzkowski, B; Rózycki, Z; Wilejczyk, E; Smoter, J

    2000-01-01

    Swieradrów Zdrój and Czerniawa Zdrój are located in Region Izera Block. A total of 789 radon passive dosimeters were distributed in 183 dwellings in these town Swieradów Zdrój and Czerniawa Zdrój to measure the indoor radon concentration in 1999. Three-five measurements were performed in each dwelling, one in the basement, and the others in the main bedroom, in the kitchen, in the bathroom, since these rooms are the most frequently occupied. In addition, the occupants of each dwelling were requested to answer a questionnaire in which a number of questions about the building, ventilation habits and other related aspects were formulated. A charcoal detectors (Pico-Rad system) were used in experiment. It is a passive short-term screening method of radon gas concentration measurements. The indoor radon level was found to range from 14.8 Bq/m3 to 5,723.9 Bq/m3. The arithmetic mean overall indoor concentration was 420.4 Bq/m3 and the geometric mean was 159.7 Bq/m3. The average concentration of indoor radon, which reflects the real risk for inhabitants, is 193.5 Bq/m3. The results hand a log-normal distribution. In Poland, an action level of 400 Bq/m3 was recommended for existing buildings and 200 Bq/m3 for newly built (after 1.01.1998) buildings. In about 23% rooms the level of Rn-222 were above the top limit of 400 Bq/m3. The highest average concentrations were present in a basement (mean 919.9 Bq/m3). A decrease of average activity were observed at the upper levels: at the ground floor (225.2 Bq/m3), at the first floor and at the higher floors (137.6 Bq/m3). The above results indicate that radon emission from the ground provides the main contribution to the radon concentration measured in dwellings indoors in Swieradów Zdrój and Czerniawa Zdrój. The effective dose to the population of the Swieradów Zdrój and Czerniawa Zdrój from indoor radon and its progeny can be derived from this data if we use an equilibrium factor of 0.4 between radon and its progeny

  1. Radon progeny size distributions and enhanced deposition effects from high radon concentrations in an enclosed chamber.

    PubMed

    Leonard, Bobby E

    2004-01-01

    Prior work studying radon progeny in a small enclosed chamber found that at high (222)Rn concentrations an enhanced surface deposition was observed. Subsequent measurements for unfiltered air showed minimal charged particle mobility influence. Progeny particle size measurements reported here, performed at the US Department of Energy Environmental Measurement Laboratory (now with Home Security Department), using the EML graded screen array (GSA) system show in unfiltered air that the high (222)Rn levels causes a reduction in the attached (218)Po progeny airborne particulates and formation of additional normal sized unattached ( approximately 0.80 nm) and also even smaller (218)Po below 0.50 nm. At a (222)Rn level of 51 kBq m(-3), 73% of all (218)Po are of a mean particle diameter of about 0.40 +/- 0.02 nm. At this (222)Rn level, the ratio of (218)Po to (222)Rn airborne concentrations is reduced significantly from the concentration ratio at low (222)Rn levels. Similar reductions and size reformations were observed for the (214)Pb and (214)Bi/Po progeny. The particle size changes are further confirmed using the plateout rates and corresponding deposition velocities. The Crump and Seinfeld deposition theory provides the corresponding particle diffusion coefficients. With the diffusion coefficient to ultrafine clustered particle diameter correlation of Ramamurthi and Hopke, good agreement is obtained between EML GSA and deposition velocity data down to 0.40 nm. Strong evidence is presented that the progeny size reduction is due to, as a result of air ionization, the increased neutralization rate (primarily from electron scavenging of OH molecules) of the initially charged progeny. This is shown to increase with the (1/2) power of (222)Rn concentration and relative humidity as well as increased air change rate in the chamber. These results imply that at (222)Rn levels above 50 kBq m(-3), at relative humidity of 52%, a considerable reduction in lung dose could occur from

  2. Daily variation of radon gas and its short-lived progeny concentration near ground level and estimation of aerosol residence time

    NASA Astrophysics Data System (ADS)

    M, Mohery; A, M. Abdallah; A, Ali; S, S. Baz

    2016-05-01

    Atmospheric concentrations of radon (222Rn) gas and its short-lived progenies 218Po, 214Pb, and 214Po were continuously monitored every four hours at the ground level in Jeddah city, Kingdom of Saudi Arabia. The measurements were performed three times every week, starting from November 2014 to October 2015. A method of electrostatic precipitation of positively charged 218Po and 214Po by a positive voltage was applied for determining 222Rn gas concentration. The short-lived 222Rn progeny concentration was determined by using a filter holder connected with the alpha-spectrometric technique. The meteorological parameters (relative air humidity, air temperature, and wind speed) were determined during the measurements of 222Rn and its progeny concentrations. 222Rn gas as well as its short-lived progeny concentration display a daily and seasonal variation with high values in the night and early morning hours as compared to low values at noon and in the afternoon. The observed monthly atmospheric concentrations showed a seasonal trend with the highest values in the autumn/winter season and the lowest values in the spring/summer season. Moreover, and in parallel with alpha-spectrometric measurements, a single filter-holder was used to collect air samples. The deposited activities of 214Pb and the long-lived 222Rn daughter 210Pb on the filter were measured with the gamma spectrometric technique. The measured activity concentrations of 214Pb by both techniques were found to be relatively equal largely. The highest mean seasonally activity concentrations of 210Pb were observed in the autumn/winter season while the lowest mean were observed in the spring/summer season. The mean residence time (MRT) of aerosol particles in the atmospheric air could be estimated from the activity ratios of 210Pb/214Pb. Project supported by the Deanship of Scientific Research (DSR), King Abdulaziz University, Jeddah (Grant No. 291/965/1434).

  3. Adsorption and desorption of noble gases on activated charcoal: II. sup 222 Rn studies in a monolayer and packed bed

    SciTech Connect

    Scarpitta, S.C.; Harley, N.H. )

    1990-10-01

    The adsorptive and desorptive characteristics of canisters containing a petroleum-based charcoal were investigated under controlled conditions of temperature, relative humidity, and Rn concentration. Charcoals exposed in a monolayer and packed bed during exposure intervals of 1-7 d demonstrate that Rn adsorption and desorption are dependent on bed depth and the amount of water adsorbed. Changes in the adsorptive and desorptive properties of the charcoal occurred near the break-point where the pores became occluded by water vapor that condenses in the entrance capillaries. Radon-222 adsorption is decreased by an order of magnitude as the amount of adsorbed water exceeds the break-point of the charcoal. The reduction in pore surface due to adsorbed water results in a marked increase in the rate of Rn loss from exposed canisters, accounting for reduced adsorption. The apparent desorption time-constant for a 2-cm bed of loose Witco 6 x 10 mesh charcoal containing 0.220-0.365 kg H{sub 2}O kg-1 is typically between 2-8 h. The apparent desorption time-constant for an equivalent packed bed containing a water vapor content of 0.026-0.060 kg H{sub 2}O kg-1, which is below the break-point of the charcoal, is about 15-30 h. Conventional charcoal canisters, if exposed in the fully-opened configuration, can achieve the break-point in less than 4 d at 70% humidity. The use of a diffusion barrier would allow for longer exposure times until the break-point of the charcoal is achieved.

  4. Application of spectral decomposition of ²²²Rn activity concentration signal series measured in Niedźwiedzia Cave to identification of mechanisms responsible for different time-period variations.

    PubMed

    Przylibski, Tadeusz Andrzej; Wyłomańska, Agnieszka; Zimroz, Radosław; Fijałkowska-Lichwa, Lidia

    2015-10-01

    The authors present an application of spectral decomposition of (222)Rn activity concentration signal series as a mathematical tool used for distinguishing processes determining temporal changes of radon concentration in cave air. The authors demonstrate that decomposition of monitored signal such as (222)Rn activity concentration in cave air facilitates characterizing the processes affecting changes in the measured concentration of this gas. Thanks to this, one can better correlate and characterize the influence of various processes on radon behaviour in cave air. Distinguishing and characterising these processes enables the understanding of radon behaviour in cave environment and it may also enable and facilitate using radon as a precursor of geodynamic phenomena in the lithosphere. Thanks to the conducted analyses, the authors confirmed the unquestionable influence of convective air exchange between the cave and the atmosphere on seasonal and short-term (diurnal) changes in (222)Rn activity concentration in cave air. Thanks to the applied methodology of signal analysis and decomposition, the authors also identified a third process affecting (222)Rn activity concentration changes in cave air. This is a deterministic process causing changes in radon concentration, with a distribution different from the Gaussian one. The authors consider these changes to be the effect of turbulent air movements caused by the movement of visitors in caves. This movement is heterogeneous in terms of the number of visitors per group and the number of groups visiting a cave per day and per year. Such a process perfectly elucidates the observed character of the registered changes in (222)Rn activity concentration in one of the decomposed components of the analysed signal. The obtained results encourage further research into precise relationships between the registered (222)Rn activity concentration changes and factors causing them, as well as into using radon as a precursor of

  5. A diffusion chamber for passive separated measurements of radon/thoron concentration in dwellings

    NASA Astrophysics Data System (ADS)

    Torabi Nabil, F.; Hosseini Pooya, S. M.; Shamsaie Zafarghandi, M.; Taheri, M.

    2012-12-01

    In this research, a passive diffusion chamber has been developed for separated measurement of radon and thoron. The chamber consists of two volumes which are separated by a fiber glass filter. Two lexan polycarbonate nuclear track detectors (film) are placed inside of the volumes to detect the alpha particles of radon/thorn and/or their progenies. Another lexan polycarbonate detector covered with an optimized thickness of an attenuator is placed outside of the chamber to measure only 212Po which its concentration can be related to that of long-life thoron progeny, 212Pb. The sensitivities have been measured by 2.06 and 0.053 [tracks cm-2(kBq m-3 day)-1] values for radon and thoron respectively inside of the chamber, and 7960 [tracks cm-2(kBq m-3 day)-1] value for thoron outside of the chamber. So the system can be successfully used for separated measurement of an extended range of radon/thoron concentrations in dwellings.

  6. Procedure for the characterization of radon potential in existing dwellings and to assess the annual average indoor radon concentration.

    PubMed

    Collignan, Bernard; Powaga, Emilie

    2014-11-01

    Risk assessment due to radon exposure indoors is based on annual average indoor radon activity concentration. To assess the radon exposure in a building, measurement is generally performed during at least two months during heating period in order to be representative of the annual average value. This is because radon presence indoors could be very variable during time. This measurement protocol is fairly reliable but may be a limiting in the radon risk management, particularly during a real estate transaction due to the duration of the measurement and the limitation of the measurement period. A previous field study defined a rapid methodology to characterize radon entry in dwellings. The objective of this study was at first, to test this methodology in various dwellings to assess its relevance with a daily test. At second, a ventilation model was used to assess numerically the air renewal of a building, the indoor air quality all along the year and the annual average indoor radon activity concentration, based on local meteorological conditions, some building characteristics and in-situ characterization of indoor pollutant emission laws. Experimental results obtained on thirteen individual dwellings showed that it is generally possible to obtain a representative characterization of radon entry into homes. It was also possible to refine the methodology defined in the previous study. In addition, numerical assessments of annual average indoor radon activity concentration showed generally a good agreement with measured values. These results are encouraging to allow a procedure with a short measurement time to be used to characterize long-term radon potential in dwellings. PMID:25011073

  7. Method of and apparatus for measuring the mean concentration of thoron and/or radon in a gas mixture

    DOEpatents

    Lucas, Henry

    1990-01-01

    A method of and an apparatus for detecting and accurately measuring the mean concentrations of .sup.222 Rn and .sup.220 Tn in a gas mixture, such as the ambient atmosphere in a mine, is provided. The apparatus includes an alpha target member which defines at least one operative target surface and which is preferably fabricated from a single piece of an alpha particle sensitive material. At least one portion of the operative target surface is covered with an alpha particle filter. The uncovered and filter covered operative surface is exposed to the gas mixture containing the .sup.222 Rn and .sup.220 Tn. In the radioactive decay series of these isotopes the maximum kinetic energy emitted by the alpha decay of .sup.222 Rn is about 1.1 MeV less than the maximum kinetic energy emitted by the alpha decay of a .sup.220 Tn. The alpha particle filter has a predetermined mass per unit area of the covered portion of the operative target surface that prevents penetration of alpha particles which originate from .sup.222 Rn decay, but which allows passage therethrough of the maximum kinetic energy alpha particles from .sup.220 Tn decay. Thus, a count of the alpha particle tracks in the uncovered portion of the target member is proportional to the mean concentration of sum of .sup.222 Rn and .sup.220 Tn in the gas mixture, while the count of alpha tracks in the target member under the filter is proportional to the concentration of only the .sup.220 Tn in the gas mixture.

  8. Retrospective assessment of historic radon concentrations in Norwegian dwellings by measuring glass implanted Po-210--an international field intercomparison.

    PubMed

    Birovljev, A; Falk, R; Walsh, C; Bissolo, F; Trotti, F; McLaughlin, J P; Paridaens, J; Vanmarcke, H

    2001-05-14

    The first Norwegian study of historic radon concentrations in 17 dwellings in the high radon areas in Norway has been conducted as part of an international field intercomparison during 1998. The retrospective radon concentration is estimated via measurements of Po-210, the long-lived decay product of Rn-222 implanted in glass surfaces of objects like pictures, mirrors, cabinet-glass, etc. the method called 'surface trap'. Three different surface trap techniques to assess the implanted Po-210 activity and two different procedures to estimate retro radon from Po-210 data were used. The Po-210 and the retrospectively estimated radon results agree reasonably well over a wide range of concentrations. Historic radon concentrations were also estimated from analysis of a smaller number of 'volume trap' samples (pieces of spongy materials), and the results compared to those from 'surface traps'. The retro radon results correlate with contemporary radon results with a correlation coefficient of 0.877. To evaluate uncertainty in Po-210 measurements due to varying position on the glass a study of spatial homogeneity of three sample glasses was conducted and variations between 12% and 18% were found. PMID:11379908

  9. {sup 222}Rn in water: A comparison of two sample collection methods and two sample transport methods, and the determination of temporal variation in North Carolina ground water

    SciTech Connect

    Hightower, J.H. III

    1994-12-31

    Objectives of this field experiment were: (1) determine whether there was a statistically significant difference between the radon concentrations of samples collected by EPA`s standard method, using a syringe, and an alternative, slow-flow method; (2) determine whether there was a statistically significant difference between the measured radon concentrations of samples mailed vs samples not mailed; and (3) determine whether there was a temporal variation of water radon concentration over a 7-month period. The field experiment was conducted at 9 sites, 5 private wells, and 4 public wells, at various locations in North Carolina. Results showed that a syringe is not necessary for sample collection, there was generally no significant radon loss due to mailing samples, and there was statistically significant evidence of temporal variations in water radon concentrations.

  10. Evaluation and source attribution of freshwater contributions to Kinvarra Bay, Ireland, using (222)Rn, EC and stable isotopes as natural indicators.

    PubMed

    Schubert, Michael; Knoeller, Kay; Rocha, Carlos; Einsiedl, Florian

    2015-03-01

    Freshwater discharge into the coastal sea is of general interest for two reasons: (i) It acts as vehicle for the transport of contaminants or nutrients into the ocean, and (ii) it indicates the loss of significant volumes of freshwater that might be needed for irrigation or drinking water supply. Due to the large-scale and long-term nature of the related hydrological processes, locating and quantitatively assessing freshwater discharge into the sea require naturally occurring tracers that allow fast, inexpensive and straightforward detection. In several studies, the standard water parameters electrical conductivity (EC) and pH have proven their suitability in this regard. However, while distribution patterns of EC and pH in the coastal sea indicate freshwater discharge in general, a separation between discharging surface water and submarine groundwater discharge (SGD) is not possible with these alone. The naturally occurring radionuclide radon-222 has been shown to be useful in the quantification of SGD and its distinction from surface runoff. This study aimed to evaluate and compare the informative value of the three parameters-EC, pH and radon concentration-in detecting and quantifying SGD by carrying out a case study in a bay located in western Ireland. The results reveal that radon activity is the most sensitive parameter for detecting SGD. However, only the combined evaluation of radon, EC and pH allows a quantitative allocation of groundwater and surface water contributions to the overall freshwater discharge into the sea. This conclusion is independently supported by stable isotope data measured on selected samples. PMID:25666648

  11. Radon concentration in groundwater of the Yongin area in Korea by using LSC

    NASA Astrophysics Data System (ADS)

    Cho, Sooyoung; Lee, Kilyong; Yoon, Yoonyeol; Yun, Uk; Cho, Byungwook; Ha, kyoochul; Koo, Minho

    2015-04-01

    The precise determination of 222Rn concentration in ground water is very important to understand the interactions between the groundwater and surface water interactions because it has been used frequently as a tracer for many geohydrological processes. In this study, the measurement was based on the liquid scintillation counting technique using LKB Wallac Quantulus 1220 liquid scintillation counter(LSC) equipped with pulse shape analyzer(PSA). We have optimized the pulse-discrimination capabilities of the detector to achieve the best α/β separation, which made the lowest detection limit possible. LSC was calibrated to optimize the PSA with 241Am and 90Sr/90Y. The sample was collected from 100 groundwater sites in the Yoingin area, Korea. The relationship between chemical characteristics and depth was investigated in terms of EC, pH, and temperature. The concentration of 222Rn in ground water was measured to be about 0.6 to 678 Bq/l with an average of 217 Bq/L. However, there was no relationship between the Rn and other physicochemical components. The Rn concentration in ground water was 170 Bq/L, 210 Bq/L, 260 Bq/L for depth <50 m, 50-100 m, >100 m, respectively. When viewed from the average value, 222Rn in deep ground was relatively higher. It also was dependent on the geolocial legend: The high-Rn area corresponds to Jurassuc grabute and low-Rn to Sedunentary area. It was clearly demonstrated that the occurrence of radionuclides is closely related to radiogenic minerals. Key words: Grondwater, 222Rn, LSC, chemical characteristics, geolocial legend

  12. Estimation of EEC, unattached fraction and equilibrium factor for the assessment of radiological dose using pin-hole cup dosimeters and deposition based progeny sensors.

    PubMed

    Bangotra, Pargin; Mehra, Rohit; Kaur, Kirandeep; Kanse, Sandeep; Mishra, Rosaline; Sahoo, B K

    2015-10-01

    High concentration of radon ((222)Rn), thoron ((220)Rn) and their decay products in environment may increase the risk of radiological exposure to the mankind. The (222)Rn, (220)Rn concentration and their separate attached and unattached progeny concentration in units of EEC have been measured in the dwellings of Muktsar and Mansa districts of Punjab (India), using Pin-hole cup dosimeters and deposition based progeny sensors (DTPS/DRPS). The indoor (222)Rn and (220)Rn concentration was found to vary from 21 Bqm(-3) to 94 Bqm(-3) and 17 Bqm(-3) to 125 Bqm(-3). The average EEC (attached + unattached) of (222)Rn and (220)Rn was 25 Bqm(-3) and 1.8 Bqm(-3). The equilibrium factor for (222)Rn and (220)Rn in studied area was 0.47 ± 0.13 and 0.05 ± 0.03. The equilibrium factor and unattached fraction of (222)Rn and (220)Rn has been calculated separately. Dose conversion factors (DCFs) of different models have been calculated from unattached fraction for the estimation of annual effective dose in the studied area. From the experimental data a correlation relationship has been observed between unattached fraction (f(p)(Rn)) and equilibrium factor (F(Rn)). The present work also aims to evaluate an accurate expression among available expression in literature for the estimation of f(p)(Rn). PMID:26117280

  13. Dwelling Designers

    ERIC Educational Resources Information Center

    Szekely, George

    2012-01-01

    Children's inventions go far beyond track housing or Ethan Allen furniture; they foreshadow the most innovative ideas in building forms and interior designs. Children improvise with containers and find places in a home that suggest enticing dwellings. A drawer left open becomes a balcony, soap trays become cots, and the space between twin beds…

  14. Measurement and apportionment of radon source terms for modeling indoor environments. Final progress report, March 1990--August 1992

    SciTech Connect

    Harley, N.H.

    1992-12-31

    During the present 2 1/2 year contract period, we have made significant Progress in modeling the source apportionment of indoor {sup 222}Rn and in {sup 222}Rn decay product dosimetry. Two additional areas were worked on which we believe are useful for the DOE Radon research Program. One involved an analysis of the research house data, grouping the hourly house {sup 222}Rn measurements into 2 day, 7 day and 90 day intervals to simulate the response of passive monitors. Another area requiring some attention resulted in a publication of 3 years of our indoor/outdoor measurements in a high-rise apartment. Little interest has been evinced in apartment measurements yet 20% of the US population lives in multiple-family dwellings, not in contact with the ground. These data together with a summary of all other published data on apartments showed that apartments have only about 50% greater {sup 222}Rn concentration than the measured outdoor {sup 222}Rn. Apartment dwellers generally represent a low risk group regarding {sup 222}Rn exposure. The following sections describe the main projects in some detail.

  15. Measurement and apportionment of radon source terms for modeling indoor environments

    SciTech Connect

    Harley, N.H.

    1992-01-01

    During the present 2 1/2 year contract period, we have made significant Progress in modeling the source apportionment of indoor [sup 222]Rn and in [sup 222]Rn decay product dosimetry. Two additional areas were worked on which we believe are useful for the DOE Radon research Program. One involved an analysis of the research house data, grouping the hourly house [sup 222]Rn measurements into 2 day, 7 day and 90 day intervals to simulate the response of passive monitors. Another area requiring some attention resulted in a publication of 3 years of our indoor/outdoor measurements in a high-rise apartment. Little interest has been evinced in apartment measurements yet 20% of the US population lives in multiple-family dwellings, not in contact with the ground. These data together with a summary of all other published data on apartments showed that apartments have only about 50% greater [sup 222]Rn concentration than the measured outdoor [sup 222]Rn. Apartment dwellers generally represent a low risk group regarding [sup 222]Rn exposure. The following sections describe the main projects in some detail.

  16. Associations of phthalate concentrations in floor dust and multi-surface dust with the interior materials in Japanese dwellings.

    PubMed

    Ait Bamai, Yu; Araki, Atsuko; Kawai, Toshio; Tsuboi, Tazuru; Saito, Ikue; Yoshioka, Eiji; Kanazawa, Ayako; Tajima, Shuji; Shi, Cong; Tamakoshi, Akiko; Kishi, Reiko

    2014-01-15

    Phthalates are widely used as plasticizers in numerous products. However, there has been some concern about the various effects they may have on human health. Thus, household phthalate levels are an important public health issue. While many studies have assessed phthalate levels in house dust, the association of these levels with building characteristics has scarcely been examined. The present study investigated phthalate levels in house dust samples collected from the living areas of homes, and examined associations between these phthalate levels and the interior materials. Dust was collected from two portions of the living area: floor dust from the entire floor surface, and multi-surface dust from objects more than 35 cm above the floor. The levels of seven phthalates were measured using gas chromatography/mass spectrometry in selective ion monitoring mode. Phthalate levels were higher in multi-surface dust than in floor dust. Among floor dust samples, those from dwellings with compressed wooden flooring had significantly higher levels of di-iso-butyl phthalate compared to those with other floor materials, while polyvinyl chloride (PVC) flooring was associated with higher di-2-ethylhexyl phthalate (DEHP) levels. Among multi-surface dust samples, higher levels of DEHP and di-iso-nonyl phthalate (DINP) were found in samples from homes with PVC wallpaper than without. The number of PVC interior materials was significantly positively correlated with the levels of DEHP and DINP in multi-surface dust. The phthalate levels in multi-surface dust were associated with the interior surface materials, and those in floor dust were directly related to the flooring materials. Our findings show that when using house dust as an exposure assessment, it is very important to note where the samples were collected from. The present report provides useful information about the association between phthalates and dust inside dwellings, which will assist with establishing public health

  17. Radon Concentrations in Drinking Water in Beijing City, China and Contribution to Radiation Dose

    PubMed Central

    Wu, Yun-Yun; Ma, Yong-Zhong; Cui, Hong-Xing; Liu, Jian-Xiang; Sun, Ya-Ru; Shang, Bing; Su, Xu

    2014-01-01

    222Rn concentrations in drinking water samples from Beijing City, China, were determined based on a simple method for the continuous monitoring of radon using a radon-in-air monitor coupled to an air-water exchanger. A total of 89 water samples were sampled and analyzed for their 222Rn content. The observed radon levels ranged from detection limit up to 49 Bq/L. The calculated arithmetic and geometric means of radon concentrations in all measured samples were equal to 5.87 and 4.63 Bq/L, respectively. The average annual effective dose from ingestion of radon in drinking water was 2.78 μSv, and that of inhalation of water-borne radon was 28.5 μSv. It is concluded that it is not the ingestion of waterborne radon, but inhalation of the radon escaping from water that is a substantial part of the radiological hazard. Radon in water is a big concern for public health, especially for consumers who directly use well water with very high radon concentration. PMID:25350007

  18. Is Radon Emission in Caves Causing Deletions in Satellite DNA Sequences of Cave-Dwelling Crickets?

    PubMed Central

    Allegrucci, Giuliana; Sbordoni, Valerio; Cesaroni, Donatella

    2015-01-01

    The most stable isotope of radon, 222Rn, represents the major source of natural radioactivity in confined environments such as mines, caves and houses. In this study, we explored the possible radon-related effects on the genome of Dolichopoda cave crickets (Orthoptera, Rhaphidophoridae) sampled in caves with different concentrations of radon. We analyzed specimens from ten populations belonging to two genetically closely related species, D. geniculata and D. laetitiae, and explored the possible association between the radioactivity dose and the level of genetic polymorphism in a specific family of satellite DNA (pDo500 satDNA). Radon concentration in the analyzed caves ranged from 221 to 26000 Bq/m3. Specimens coming from caves with the highest radon concentration showed also the highest variability estimates in both species, and the increased sequence heterogeneity at pDo500 satDNA level can be explained as an effect of the mutation pressure induced by radon in cave. We discovered a specific category of nuclear DNA, the highly repetitive satellite DNA, where the effects of the exposure at high levels of radon-related ionizing radiation are detectable, suggesting that the satDNA sequences might be a valuable tool to disclose harmful effects also in other organisms exposed to high levels of radon concentration. PMID:25822625

  19. Effects of vegetation of radon transport processes in soil: The origins and pathways of {sup 222}Rn entering into basement structures. Final report, March 15, 1987--May 15, 1993

    SciTech Connect

    Borak, T.B.

    1992-08-01

    The entry rate of {sup 22}Rn into a basement structure was measured continuously. These measurements demonstrated that radon entry did not vanish even when the structure was slightly pressurized. This persistent entry has been determined to be dominated by diffusion through the floor and walls and a combination of diffusion and convection through the floor-wall joint. The highest indoor radon concentrations occurred during calm periods when the pressure differentials between the inside and outside of the structure were small. The objectives of this work were to identify the origins of the radon and investigate the entry pathways. The radon could originate either in the concrete or in the soil surrounding the structure. Entry pathways into the basement were through the concrete floor and walls as well as through the floor-wall joint. The contributions of the origins and entry pathways were determined by continuously measuring the radon entry rate into the basement, using a trace gas system, and the flux density through portions of the floor and walls. Radon entry through the floor-wall joint could be controlled using a baseboard barrier system. Results indicated that, during calm conditions with wind speeds less than 1 m s{sup {minus}1}, 25 % of the radon enters through the floor-wall joint and 75 % enters through the concrete. About 30 % of the radon originated in the concrete floor and walls. A method for in-situ determination of the diffusion length and emanation fraction of radon in concrete was developed. For the concrete used in the structure, the average diffusion length and emanation fraction were 27{plus_minus}4 cm and 0.19{plus_minus}0.02 respectively.

  20. Parametric modelling of temporal variations in radon concentrations in homes

    SciTech Connect

    Revzan, K.L.; Turk, B.H.; Harrison, J.; Nero, A.V.; Sextro, R.G.

    1988-01-01

    The /sup 222/Rn concentrations in the living area, the basement, and the undelying soil of a New Jersey home have been measured at half-hour intervals over the course of a year, as have indoor and outdoor temperatures, wind speed and direction, and indoor-outdoor and basement-subslab pressures; in addition, periods of furnace opration have been logged. We generalize and extend an existing radon entry model in order to demonstrate the dependence of the radon concentration on the environmental variales and the extent of furnace use. The model contains parameters which are dependent on geological and structural factors which have not been measured or otherwise determined; statistical methods are used to find the best values of the parameters. The non-linear regression of the model predictions (over time) on the measured living area radon concentrations yields an R)aup 2) of 0.88. 9 refs., 2 figs

  1. Analyzing spatial and temporal (222)Rn trends in Maine.

    PubMed

    Farah, Christopher; Beard, Kate; Hess, C T; Hock, Janet M

    2012-02-01

    Prolonged radon exposure has been linked to lung cancer. Cancer registry data indicates excess risk for age-adjusted lung cancer in Maine. Maine's mean residential radon activity exceeds the EPA maximum contaminant level (MCL). This paper describes the application of spatial autocorrelation methods to retrospective data as a means of analyzing radon activity in Maine. Retrospective air and well water radon activity data, sampled throughout Maine between 1993 and 2008, are standardized and geocoded for analysis. Three spatial autocorrelation algorithms-local Getis-Ord, local Moran, and spatial scan statistic-are used to identify spatial, temporal, and spatiotemporal radon activity clusters and/or outliers. Spatial clusters of high air- and well water-Rn activity are associated with Maine's Lucerne and Sebago granitic formations. Spatial clusters of low air- and well water-Rn activity are associated with Biddeford Granite and the metamorphic bedrock formation Silurian Ordovician Vassalboro. Space-time analysis indicates that most spatial clusters persist over the period of sampling. No significant temporal clusters are identified. Persistent spatial variations in radon may help to better understand and predict radon-related health risks associated with Maine residences. PMID:22217584

  2. Measurements of radon flux and soil-gas radon concentration along the Main Central Thrust, Garhwal Himalaya, using SRM and RAD7 detectors

    NASA Astrophysics Data System (ADS)

    Bourai, Abhay; Aswal, Sunita; Dangwal, Anoop; Rawat, Mukesh; Prasad, Mukesh; Naithani, Nagendra; Joshi, Veena; Ramola, Rakesh

    2013-08-01

    Radon in the Earth's crust or soil matrix is free to move only if its atoms find their way into pores or capillaries of the matrix. 222Rn atoms from solid mineral grains get into air, filling pores through emanation process. Then 222Rn enters into the atmosphere from air-filled pores by exhalation process. The estimation of radon flux from soil surface is an important parameter for determining the source term for radon concentration modeling. In the present investigation, radon fluxes and soil-gas radon concentration have been measured along and around the Main Central Thrust (MCT) in Uttarkashi district of Garhwal Himalaya, India, by using Scintillation Radon Monitor (SRM) and RAD7 devices, respectively. The soil radon gas concentration measured by RAD7 with soil probe at the constant depth was found to vary from 12 ± 3 to 2330 ± 48 Bq·m-3 with geometrical mean value of 302 ± 84 Bq·m-3. Th significance of this work is its usefulness from radiation protection point of view.

  3. International comparison of cave radon concentrations identifying the potential alpha radiation risks to British cave users

    SciTech Connect

    Hyland, R.; Gunn, J.

    1994-08-01

    Elevated concentrations of {sup 222}Rn have been recorded in many limestone caves throughout the world. As prolonged exposure to high radon concentrations has been linked to cancer and tumors, particularly of the lung, a national survey of radon in British caves was undertaken. Passive radon detectors were exposed at 250 sites in 47 caves over four 7-d sampling periods. Mean concentrations ranging from 454-8,868 Bq m{sup {minus}3} were recorded. In one system, in the Peak District, radon concentrations of 155,000 Bq m{sup {minus}3} were recorded. The results indicate that the potential radiation dose from a single 4-h trip could exceed the national average annual background radiation dose (for the UK) from radon of 1.25 mSv. 18 refs., 3 tabs.

  4. Determination of indoor radon concentrations at the elementary schools of Fatih district in Istanbul

    NASA Astrophysics Data System (ADS)

    Kurt, A.; Yalcin, L. Sahin; Oktem, Y.; Akkus, B.; Bozkurt, E.; Hafizoglu, N.; Ozturk, F. C.; Aytan, O.; Ertoprak, A.

    2016-03-01

    Radon is an odorless, tasteless, colorless noble radioactive gas which is produced within the radioactive decay chain of Uranium. The Radon forms in rocks, diffuses into soil and then escapes into atmosphere. When human exposure to high concentration of radon gas from inside, risk of developing lung cancer is increased. There are many methods to determine 222Rn concentration in the air. In this study, radon concentration of confined air spaces were measured by using LR-115 solid state nuclear track detectors. 509 LR-115 nuclear trace detectors were placed to 25 schools in Fatih District and they effective dose values were calculated. The results of measurements showed that the radon concentration varies between 40-395 Bq/m3. This results compared with Turkey's limits (400 Bq/m3) are low, conversely higher compared with WHO's limits (100 Bq/m3).

  5. International comparison of cave radon concentrations identifying the potential alpha radiation risks to British cave users.

    PubMed

    Hyland, R; Gunn, J

    1994-08-01

    Elevated concentrations of 222Rn have been recorded in many limestone caves throughout the world. As prolonged exposure to high radon concentrations has been linked to cancer and tumors, particularly of the lung (National Academy of Science 1988; Eatough and Henshaw 1990), a national survey of radon in British caves was undertaken. Passive radon detectors were exposed at 250 sites in 47 caves over four 7-d sampling periods. Mean concentrations ranging from 454-8,868 Bq m-3 were recorded. In one system, in the Peak District, radon concentrations of 155,000 Bq m-3 were recorded. The results indicate that the potential radiation dose from a single 4-h trip could exceed the national average annual background radiation dose (for the UK) from radon of 1.25 mSv. PMID:8026972

  6. Association between secondhand smoke exposure and blood lead and cadmium concentration in community dwelling women: the fifth Korea National Health and Nutrition Examination Survey (2010–2012)

    PubMed Central

    Jung, Se Young; Kim, Suyeon; Lee, Kiheon; Kim, Ju Young; Bae, Woo Kyung; Lee, Keehyuck; Han, Jong-Soo; Kim, Sarah

    2015-01-01

    Objectives To assess the association between secondhand smoke exposure and blood lead and cadmium concentration in women in South Korea. Design Population-based cross-sectional study. Setting South Korea (Korea National Health and Nutrition Examination Survey V). Participants 1490 non-smoking women who took part in the fifth Korea National Health and Nutrition Examination Survey (2010–2012), in which blood levels of lead and cadmium were measured. Primary outcome measures The primary outcome was blood levels of lead and cadmium in accordance with the duration of secondhand smoke exposure. Results The adjusted mean level of blood cadmium in women who were never exposed to secondhand smoke was 1.21 (0.02) µg/L. Among women who were exposed less than 1 h/day, the mean cadmium level was 1.13 (0.03) µg/L, and for those exposed for more than 1 h, the mean level was 1.46 (0.06) µg/L. In particular, there was a significant association between duration of secondhand smoke exposure at the workplace and blood cadmium concentration. The adjusted mean level of blood cadmium concentration in the never exposed women's group was less than that in the 1 h and more exposed group, and the 1 h and more at workplace exposed group: 1.20, 1.24 and 1.50 µg/L, respectively. We could not find any association between lead concentration in the blood and secondhand smoke exposure status. Conclusions This study showed that exposure to secondhand smoke and blood cadmium levels are associated. Especially, there was a significant association at the workplace. Therefore, social and political efforts for reducing the exposure to secondhand smoke at the workplace are needed in order to promote a healthier working environment for women. PMID:26185180

  7. Statistical analysis of the radon-222 potential of rocks in Virginia, U.S.A.

    USGS Publications Warehouse

    Brown, C. Erwin; Mose, D.G.; Mushrush, G.W.; Chrosniak, C.E.

    1992-01-01

    More than 3,200 indoor radon-222 (222Rn) measurements were made seasonally in an area of about 1,000 square kilometers of the Coastal Plain and Piedmont physiographic provinces in Virginia, U.S.A. Results of these measurements indicate that some geological units are associated, on the average, with twice as much indoor222Rn as other geological units, and that indoor222Rn varies seasonally. The Kruskal-Wallis test was used to test whether indoor222Rn concentrations for data gathered over the winter and summer seasons differ significantly by rock unit. The tests concluded that indoor222Rn concentrations for different rock units were not equal at the 5-percent significance level. The rocks associated with the highest median indoor222Rn concentration are specific rocks in the Mesozoic Culpeper basin, including shale and siltstone units with Jurassic diabase intrusives, and mica schists in the Piedmont physiographic province. The pre-Triassic Peters Creek Schist has the highest ranking in terms of indoor222Rn concentration. The rocks associated with the lowest indoor222Rn concentrations include coastal plain sediments, the Occoquan Granite, Falls Church Tonalite, Piney Branch Mafic and Ultramafic complex, and unnamed mafic and ultramafic inclusions, respectively. The rocks have been ranked according to observed222Rn concentration by transforming the average rank of indoor222Rn concentrations to z scores. ?? 1992 Springer-Verlag New York Inc.

  8. 25 CFR 700.53 - Dwelling, replacement.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Dwelling, replacement. 700.53 Section 700.53 Indians THE... Policies and Instructions Definitions § 700.53 Dwelling, replacement. The term replacement dwelling means a dwelling selected by the head of a household as a replacement dwelling that meets the criteria of...

  9. 25 CFR 700.53 - Dwelling, replacement.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Dwelling, replacement. 700.53 Section 700.53 Indians THE... Policies and Instructions Definitions § 700.53 Dwelling, replacement. The term replacement dwelling means a dwelling selected by the head of a household as a replacement dwelling that meets the criteria of...

  10. Minimum energy dwelling

    NASA Astrophysics Data System (ADS)

    1981-07-01

    The two detached single family dwellings in the Mission Viejo community in California were monitored for the temperature and flow rate of water and air at some 45 points throughout the domestic hot water, mechanical conditioning, and solar energy systems. On site weather data were collected. Testing of levels of odor and moisture was performed to determine the effect of the tighter than average construction methods used in the MED houses. Electric consumption data for the mechanical system and household consumption were recorded separately. Utility cost records were maintained as a measure of savings between the MED houses and the standard Cordova model. Analyses and results of the data are presented.

  11. Three-body dwell time

    SciTech Connect

    Kelkar, N. G.

    2010-06-15

    The lifetime of an unstable state or resonance formed as an intermediate state in two-body scattering is known to be related to the dwell time or the time spent within a given region of space by the two interacting particles. This concept is extended to the case of three-body systems and a relation connecting the three-body dwell time with the two-body dwell times of the substructures of the three-body system is derived for the case of separable wave functions. The Kapur-Peierls formalism is revisited to discover one of the first definitions of dwell time in the literature. An extension of the Kapur-Peierls formalism to the three-body case shows that the lifetime of a three-body resonance can indeed be given by the three-body dwell time.

  12. Setting radon-specific release criteria and demonstrating compliance for land affected by NORM.

    PubMed

    García-Talavera, M; Martínez, M; Matarranz, J L M; Ramos, L

    2008-11-01

    Residues from industrial activities involving naturally occurring radioactive materials (NORMs) may cause radiation exposures to members of the public, particularly when NORM-affected land is brought into residential use. To provide an adequate protection against radiation in such situations, the following limiting criteria are currently required in Spain for releasing NORM-affected land: (i) no more than a 300 microSv yr(-1) increase (excluding radon doses) over the natural background; (ii) (222)Rn concentrations in hypothetical future dwellings lower than 200 Bq m(-3); and (iii) reduction of all radiation exposures to as low as reasonable achievable. This paper addresses some of the problems encountered in translating the (222)Rn criterion into site-specific release limits and in demonstrating compliance with them. PMID:18508275

  13. Temporal variation of thoron decay product concentration in the atmosphere and comparison with radon decay product concentration.

    PubMed

    Winkler, R; Aehlig, K

    1998-04-01

    Seasonal and long-term variation of the airborne 212Pb concentration, representative of the equilibrium equivalent concentration of thoron decay products (EECRn220), was investigated from 1989 through 1996 at a semi-natural location in southern Germany. Continuous measurement yielded a long-term average concentration of 0.082 Bq m-3, while daily mean concentrations varied from < or = 0.01 to 0.34 Bq m-3. An average annual effective dose of 1.4 mSv due to outdoor thoron progeny concentration was estimated. This is about 2% of the dose due to the average short-lived radon progeny concentration (EECRn222) of 8.4 Bq m-3 measured for this location in the same period. In most years the seasonal pattern of 212Pb activity concentration in the atmosphere is characterized by two maxima: the first in May and the second one in September. Low concentrations are observed from November through February of each year. This is in contrast to the behaviour of the short-lived 222Rn progeny which exhibit enhanced concentrations exactly during these months. The most probable reason for the different temporal behaviour of 212Pb is the extremely reduced flux of thoron gas from the ground during the winter months. PMID:9615341

  14. Indoor environmental quality in French dwellings and building characteristics

    NASA Astrophysics Data System (ADS)

    Langer, Sarka; Ramalho, Olivier; Derbez, Mickaël; Ribéron, Jacques; Kirchner, Severine; Mandin, Corinne

    2016-03-01

    A national survey on indoor environmental quality covering 567 residences in mainland France was performed during 2003-2005. The measured parameters were temperature, relative humidity, CO2, and the indoor air pollutants: fourteen individual volatile organic compounds (VOC), four aldehydes and particulate matter PM10 and PM2.5. The measured indoor concentrations were analyzed for correlations with the building characteristics: type of dwelling, period of construction, dwelling location, type of ventilation system, building material, attached garage and retrofitting. The median night time air exchange rate (AER) for all dwellings was 0.44 h-1. The night time AER was higher in apartments (median = 0.49 h-1) than in single-family houses (median = 0.41 h-1). Concentration of formaldehyde was approximately 30% higher in dwellings built after 1990 compared with older ones; it was higher in dwellings with mechanical ventilation and in concrete buildings. The VOC concentrations depended on the building characteristics to various extents. The sampling season influenced the majority of the indoor climate parameters and the concentrations of the air pollutants to a higher degree than the building characteristics. Multivariate linear regression models revealed that the indoor-outdoor difference in specific humidity, a proxy for number of occupants and their indoor activities, remained a significant predictor for most gaseous and particulate air pollutants. The other strong predictors were outdoor concentration, smoking, attached garage and AER (in descending order).

  15. 12 CFR 541.10 - Dwelling unit.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Dwelling unit. 541.10 Section 541.10 Banks and... FEDERAL SAVINGS ASSOCIATIONS § 541.10 Dwelling unit. The term dwelling unit means the unified combination of rooms designed for residential use by one family, other than a single-family dwelling....

  16. RAETRAD MODEL OF RADON GAS GENERATION, TRANSPORT, AND INDOOR ENTRY

    EPA Science Inventory

    The report describes the theoretical basis, implementation, and validation of the Radon Emanation and Transport into Dwellings (RAETRAD) model, a conceptual and mathematical approach for simulating radon (222Rn) gas generation and transport from soils and building foundations to ...

  17. Factors controlling volatile organic compounds in dwellings in Melbourne, Australia.

    PubMed

    Cheng, M; Galbally, I E; Molloy, S B; Selleck, P W; Keywood, M D; Lawson, S J; Powell, J C; Gillett, R W; Dunne, E

    2016-04-01

    This study characterized indoor volatile organic compounds (VOCs) and investigated the effects of the dwelling characteristics, building materials, occupant activities, and environmental conditions on indoor VOC concentrations in 40 dwellings located in Melbourne, Australia, in 2008 and 2009. A total of 97 VOCs were identified. Nine VOCs, n-butane, 2-methylbutane, toluene, formaldehyde, acetaldehyde, d-limonene, ethanol, 2-propanol, and acetic acid, accounted for 68% of the sum of all VOCs. The median indoor concentrations of all VOCs were greater than those measured outdoors. The occupant density was positively associated with indoor VOC concentrations via occupant activities, including respiration and combustion. Terpenes were associated with the use of household cleaning and laundry products. A petroleum-like indoor VOC signature of alkanes and aromatics was associated with the proximity of major roads. The indoor VOC concentrations were negatively correlated (P < 0.05) with ventilation. Levels of VOCs in these Australian dwellings were lower than those from previous studies in North America and Europe, probably due to a combination of an ongoing temporal decrease in indoor VOC concentrations and the leakier nature of Australian dwellings. PMID:25788118

  18. 7 CFR 3550.57 - Dwelling requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... in 7 CFR part 1924, subpart A. (c) Existing dwellings. Existing dwellings must be structurally sound..., heating, plumbing, water, and wastewater disposal systems; and be free of termites and other wood...

  19. 7 CFR 3550.57 - Dwelling requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... in 7 CFR part 1924, subpart A. (c) Existing dwellings. Existing dwellings must be structurally sound..., heating, plumbing, water, and wastewater disposal systems; and be free of termites and other wood...

  20. 7 CFR 3550.57 - Dwelling requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... in 7 CFR part 1924, subpart A. (c) Existing dwellings. Existing dwellings must be structurally sound..., heating, plumbing, water, and wastewater disposal systems; and be free of termites and other wood...

  1. 7 CFR 3550.57 - Dwelling requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... in 7 CFR part 1924, subpart A. (c) Existing dwellings. Existing dwellings must be structurally sound..., heating, plumbing, water, and wastewater disposal systems; and be free of termites and other wood...

  2. 7 CFR 3550.57 - Dwelling requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... in 7 CFR part 1924, subpart A. (c) Existing dwellings. Existing dwellings must be structurally sound..., heating, plumbing, water, and wastewater disposal systems; and be free of termites and other wood...

  3. Anomaly in atmospheric radon concentration: a possible precursor of the 1995 Kobe, Japan, earthquake.

    PubMed

    Yasuoka, Y; Shinogi, M

    1997-05-01

    Clear seismic-related anomalies in the radon (222Rn) concentration of the atmosphere were observed prior to the Kobe earthquake (magnitude 7.2) on 17 January 1995. The radon anomalies were observed at a monitoring station in Kobe, which is located about 20 km away from the epicenter. The means of radon concentration in the atmosphere for each day were calculated using the data observed between April 1984 and March 1994, in order to obtain the normal radon variation. The difference between the smoothed radon concentration and the smoothed mean radon concentration is the residual value. Using the weekly averages of residual values in the historical period, the weekly residual value in the validation period were predicted. The historical period was from April 1984 to March 1994. The validation period was from April 1994 to January 1996. The seismic-related radon anomaly higher than the 99% confidence limit of the residual value of radon concentration in the atmosphere was observed beginning about 2 mo before the earthquake. PMID:9106718

  4. Determination of radon concentration levels in well water in Konya, Turkey.

    PubMed

    Erdogan, M; Eren, N; Demirel, S; Zedef, V

    2013-10-01

    Radon ((222)Rn) measurements were undertaken in 16 samples of well water representing different depths and different types of aquifers found at the city centre of Konya, Central Turkey. The radon activity concentrations of the well water samples collected in the spring and summer seasons of 2012 were measured by using the radon gas analyser (AlphaGUARD PQ 2000PRO). The radon concentrations for spring and summer seasons are 2.29 ± 0.17 to 27.25 ± 1.07 and 1.44 ± 0.18 to 27.45 ± 1.25 Bq l(-1), respectively. The results at hand revealed that the radon concentration levels of the waters strictly depend on the seasons and are slightly variable with depth. Eleven of the 16 well water samples had radon concentration levels below the safe limit of 11.11 Bq l(-1) recommended by the United States Environmental Protection Agency. However, all measured radon concentration levels are well below the 100 Bq l(-1) safe limit declared by the World Health Organisation. The doses resulting from the consumption of these waters were calculated. The calculated minimum and maximum effective doses are 0.29 and 5.49 µSv a(-1), respectively. PMID:23595410

  5. Indoor radon measurements in Erzurum province of Turkey

    NASA Astrophysics Data System (ADS)

    Durak, R.; Kiran, D.; Kavaz, E.; Ekinci, N.

    2016-04-01

    Indoor radon measurements were carried out in dwellings in Erzurum province during the winter months of February 2012 to early April 2012 and the summer months of July 2012 to early September 2012. Nuclear track detector LR-115 was used for the measurements. According to the results of investigations, it was understood that the indoor radon concentration averages in dwellings are in the range of 11 ± 6 Bq m-3 - 380 ± 91 Bq m-3 in winter season and 8 ± 3 Bq m-3 - 356 ± 64 Bq m-3 in summer season. We found that the 222Rn effective dose values in the studied dwellings in winter season range from 0.278 to 9.59 mSv y-1. Also, the 222Rn effective dose values in the studied dwellings in summer season range from 0.202 to 8.98 mSv y-1. These values are within the ICPR recommended values. The radon activity has not been found to vary with seasonal changes, but also with the age, the construction mode of houses, the ventilation conditions and with specific sites and geological materials.

  6. Measurements of radon concentration levels in thermal waters in the region of Konya, Turkey.

    PubMed

    Erdogan, Mehmet; Ozdemir, Fatih; Eren, Nuretdin

    2013-01-01

    (222)Rn (radon) is one of the most important sources of natural radiation to which people are exposed. It is an alpha-emitting noble gas and it can be found in various concentrations in soil, air and in different kinds of water. In this study, we present the results of radon concentration measurements in thermal waters taken from the sources in the region of Konya located in the central part of Turkey. The radon activity concentrations in 10 thermal water samples were measured by using the AlphaGUARD PQ 2000PRO radon gas analyser in spring and summer of the year 2012. We found that radon activity concentrations range from 0.60±0.11 to 70.34±3.55 kBq m(-3) and from 0.67±0.03 to 36.53±4.68 kBq m(-3) in spring and summer, respectively. We also calculated effective doses per treatment in the spas for the spring and summer seasons. It was found that the minimum and maximum effective doses per treatment are in the range of 0.09-10.13 nSv in spring and in the range of 0.1-5.26 nSv in summer. PMID:23937805

  7. Variations of 210Pb concentrations in surface air at Thessaloniki, Greece (40°N)

    NASA Astrophysics Data System (ADS)

    Ioannidou, A.; Kotsopoulou, E.; Karanatsiou, A.; Papastefanou, C.

    2012-04-01

    Atmospheric concentrations of 210Pb were measured over the year 2009 in ground level air at Thessaloniki, Northern Greece (40°62' N, 22°95'E). The mean activity concentrations of 210Pb in surface air have been found to be 671 ± 213 μBq m-3. The highest values of monthly atmospheric concentrations of 210Pb were observed in the autumn and the lowest in the spring period. The higher values of 210Pb during autumn were attributed to frequent inversion conditions of the surface layers, resulting in an enrichment of radon and its decay products in surface air. The lower values during the winter months might be due to the low emanation of radon from the frozen or snow-covered soil. The minima of 210Pb concentrations during spring might reflect on higher washout during this period, which results in less emanation of radon from saturated with water soil, resulting in less production of 210Pb near ground-level air. The relative high values during summer are probably due to the higher 222Rn exhalation from the ground and due to the higher air mixing within the troposphere, which has as a result to carry down to the surface layer 210Pb whose origin is older air masses which entered into the free troposphere.

  8. Suspended particulate matter in dwellings - the impact of tobacco smoking

    SciTech Connect

    Revsbech, P.; Korsgaard, J.; Lundqvist, G.R.

    1987-01-01

    The indoor concentration of suspended particulate matter (SPM) was measured in 44 retrofitted and tight dwellings, which had electric cooking and were central heated and where the basic ventilation rate in median amounted 0.23 air changes per hour as measured with a tracer dilution method. The indoor concentration of SPM was in medium 230 ..mu..g/m/sup 3/ with a strong correlation to the tobacco consumption (r/sub s/ = 0.716), but with no correlation to the frequency of airing or the basic ventilation rate. Tobacco smoking seems to be the main indoor source of SPM in contemporary dwellings. The importance of these findings is underlined by epidemiologic studies on passive smoking and health. Air quality standards for the ambient air are based on certain risk groups such as infants, children, persons with chronic obstructive lung disorders, and indoor air standards should be based on the same concepts of health protection.

  9. Radon transport into dwellings: Considering groundwater as a source

    NASA Astrophysics Data System (ADS)

    Oostrom, M.; Lenhard, R. J.

    A mathematical model is used to investigate whether radon degassing from groundwater may contribute to indoor radon levels. Specifically, the transport of radon in the soil-gas phase from the groundwater-soil gas interface to under-pressurized dwellings is modelled. The question whether radon in groundwater may contribute to indoor radon levels arises from observed high radon concentrations in groundwater, and recent findings that advection in the gas phase may be an important transport mechanism for radon into slightly under-pressurized dwellings. Most previous radon transport investigations did not consider groundwater as a potential source for contributing to indoor radon. The mathematical model includes a method to directly calculate indoor radon concentrations and an equivalent continuum approach to represent cracks in concrete foundations. The results of the simulations indicate that radon, which partitions from groundwater to the soil gas, may be advectively transported by the gas phase to slightly underpressurized dwellings in relatively permeable soils such that indoor radon concentrations may exceed 148 Bq/m³, which is the action limit imposed by EPA.

  10. Geographical distribution of the annual mean radon concentrations in primary schools of Southern Serbia - application of geostatistical methods.

    PubMed

    Bossew, P; Žunić, Z S; Stojanovska, Z; Tollefsen, T; Carpentieri, C; Veselinović, N; Komatina, S; Vaupotič, J; Simović, R D; Antignani, S; Bochicchio, F

    2014-01-01

    Between 2008 and 2011 a survey of radon ((222)Rn) was performed in schools of several districts of Southern Serbia. Some results have been published previously (Žunić et al., 2010; Carpentieri et al., 2011; Žunić et al., 2013). This article concentrates on the geographical distribution of the measured Rn concentrations. Applying geostatistical methods we generate "school radon maps" of expected concentrations and of estimated probabilities that a concentration threshold is exceeded. The resulting maps show a clearly structured spatial pattern which appears related to the geological background. In particular in areas with vulcanite and granitoid rocks, elevated radon (Rn) concentrations can be expected. The "school radon map" can therefore be considered as proxy to a map of the geogenic radon potential, and allows identification of radon-prone areas, i.e. areas in which higher Rn radon concentrations can be expected for natural reasons. It must be stressed that the "radon hazard", or potential risk, estimated this way, has to be distinguished from the actual radon risk, which is a function of exposure. This in turn may require (depending on the target variable which is supposed to measure risk) considering demographic and sociological reality, i.e. population density, distribution of building styles and living habits. PMID:24231373

  11. Fluid dwell impact induces peritoneal fibrosis in the peritoneal cavity reconstructed in vitro.

    PubMed

    Aoki, Shigehisa; Noguchi, Mitsuru; Takezawa, Toshiaki; Ikeda, Satoshi; Uchihashi, Kazuyoshi; Kuroyama, Hiroyuki; Chimuro, Tomoyuki; Toda, Shuji

    2016-03-01

    Peritoneal fluid dwell impacts the peritoneum by creating an abnormal physiological microenvironment. Little is known about the precise effects of fluid dwell on the peritoneum, and no adequate in vitro models to analyze the impact of fluid dwell have been established. In this study, we developed a peritoneal fluid dwell model combined with an artificial peritoneal cavity and fluid stirring generation system to clarify the effects of different dwelling solutions on the peritoneum over time. To replicate the peritoneal cavity, we devised a reconstructed peritoneal cavity utilizing a mesothelial layer, endothelial layer, and collagen membrane chamber. The reconstructed peritoneal cavity was infused with Dulbecco's modified Eagle's medium, saline, lactated Ringer's solution or peritoneal dialysis solution with repeated 4-h dwells for 10 or 20 consecutive days. The above-described solutions induced epithelial-mesenchymal transition (EMT) and hyperplasia of mesothelial cells. All solution types modulated nitric oxide synthase activities in mesothelial and endothelial cells and nitric oxide concentrations in dwelling solutions. Inhibition of nitric oxide synthase activity acted synergistically on mesothelial EMT and hyperplasia. The present findings suggest that solutions infused into the peritoneal cavity are likely to affect nitric oxide production in the peritoneum and promote peritoneal fibrosis. Our newly devised peritoneal cavity model should be a promising tool for understanding peritoneal cellular kinetics and homeostasis. PMID:26318752

  12. Preparation of gaseous CRMs from the primary system for (222)Rn activity measurement.

    PubMed

    Kim, B J; Kim, B C; Lee, K B; Lee, J M; Park, T S

    2016-03-01

    For disseminating the gaseous radon standard traceable to the KRISS primary system based on the defined solid angle counting method, two kinds of radon CRM (a glass ampule type and a stainless steel cylinder type) were developed. The activity of the CRM was certified by subtracting a residual activity from the measured activity by the primary system. After certification, the ampule CRM was used to calibrate a radon-monitoring instrument and the cylinder CRM to calibrate an HPGe system. We also improved the measurement procedure of the radon primary system. In a typical radon energy spectrum, the radon peak overlaps with the polonium peak. For more reliable and accurate measurement of radon activity, a fitting method was adopted for the evaluation of radon area in the alpha energy spectrum. The result of radon activity evaluated by using the fitting method is in good agreement with that by the previous integration method. PMID:26778761

  13. KINETICS OF INGESTED (222)RN IN HUMANS DETERMINED FROM MEASUREMENTS WITH (133)XE

    EPA Science Inventory

    The problem of naturally occurring 222-radon contamination has received a great deal of public and scientific attention over the past several years, and has become a major public health issue worldwide. The purpose of the work reported in the document was to provide information a...

  14. 222RN AS AN INDICATOR OF NONAQUEOUS PHASE LIQUID CONTAMINATION IN GROUNDWATER. (R825689C058)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  15. Low background counting of 222Rn, 220Rn and 219Rn with electrostatic counters

    NASA Astrophysics Data System (ADS)

    Mong, Brian; EXO-200 Collaboration; nEXO Collaboration

    2014-09-01

    The radon counting technique based on electrostatic precipitation of progenies in gas followed by alpha spectroscopy has been applied to support the material selection programs of low background, neutrino and dark matter experiments with emphasis on EXO. An array of 8 counters operated by Laurentian University at SNOLAB and the Waste Isolation Pilot Plant have reached the sensitivity of 10 atoms/day in the uranium, thorium and actinium chains. Hardware improvements are underway to further increase the capacity and sensitivity in support of nEXO. The radon counting technique based on electrostatic precipitation of progenies in gas followed by alpha spectroscopy has been applied to support the material selection programs of low background, neutrino and dark matter experiments with emphasis on EXO. An array of 8 counters operated by Laurentian University at SNOLAB and the Waste Isolation Pilot Plant have reached the sensitivity of 10 atoms/day in the uranium, thorium and actinium chains. Hardware improvements are underway to further increase the capacity and sensitivity in support of nEXO. Supported by NSERC Project Grants ``Search for Double Beta Decay with EXO.''

  16. Skeletal sup 210 Pb from inhalation of sup 222 Rn and its decay products

    SciTech Connect

    Keane, A.T.; Schlenker, R.A.; Stebbings, J.H.

    1990-01-01

    Concern about health effects of radon and its decay products has recently broadened to include the potential role of radon in the causation of myeloid leukemia, multiple myeloma, and melanoma, kidney cancer, and certain childhood cancers. Description of the distribution of radon and its daughters in the skeleton and the marrow, and the dose delivered to red marrow, are of particular relevance. Our interest in a metabolic model for inhaled radon and radon decay products originated with an interest in the use of radioactivity measurement techniques in vivo to quantify the {sup 210}Pb activity of bone. In this paper we estimate the rates of transfer to body fluids of {sup 210}Pb originating from inhaled radon and radon decay products and the quantity of {sup 210}Pb deposited in compact and in cancellous bone for the ideal case of continuous exposure to a constant level of radon and its daughters. We review the contributions of ambient airborne {sup 210}Pb, diet, and active and passive smoking to skeletal levels of {sup 210}Pb, and finally, from the magnitude and the variability of the natural {sup 210}Pb content of the skeleton, we estimate the minimal rate of exposure to airborne radon and its decay products that is required to elevate the skeletal {sup 210}Pb content of an individual to a statistically significant level above the population mean skeletal {sup 210}Pb content derived from all the other environmental sources combined. 55 refs., 4 tabs.

  17. 222Rn and CO2 at Las Cañadas Caldera (Tenerife, Canary Islands)

    NASA Astrophysics Data System (ADS)

    Martin-Luis, M. C.; Steinitz, G.; Soler, V.; Quesada, M. L.; Casillas, R.

    2015-05-01

    Radon, CO2 and environmental variables are recorded during nearly three years at a shelter hosting a 505 m deep well located close to Teide volcano. Different temporal patterns are observed, annual, semi-annual, semidiurnal and multi-day fluctuations, the latter observed as gradual variation of the semidiurnal signal. CO2 is anti-correlated with atmospheric pressure at daily and at multiday scale, pointing to a barometric control on the rate of up-flow through the pipe of volcanic CO2 exsolved from the aquifer. Rn daily maximum lags pressure by 2 hours or more, exhibiting a positive correlation at the multiday scale. Also, an apparent quasi-fortnightly period is detected at Rn, CO2 and P atm during summer months, with different relations among them (reversal at CO2 compared to Rn and P atm ), pointing to a long period tidal modulation on these gases. Several anomalous large semidiurnal radon peaks were detected, some of them possibly related to seismic events within the volcanic edifice. This work defines radon baseline levels during a period of low geodynamic activity at a site which is in direct contact with a CO2 saturated aquifer that could be easily perturbed by potential unrests at the central volcanic edifice of the island.

  18. The effect of proximity to major roads on indoor air quality in typical Australian dwellings

    NASA Astrophysics Data System (ADS)

    Lawson, Sarah J.; Galbally, Ian E.; Powell, Jennifer C.; Keywood, Melita D.; Molloy, Suzie B.; Cheng, Min; Selleck, Paul W.

    2011-04-01

    An Indoor Air Quality Study of residential dwellings was carried out in Melbourne, Australia, and a subset of the data was analysed to investigate the effect of proximity to major roads on indoor air quality (IAQ). Seven-day measurements of PM 10, NO 2, benzene, toluene, ethylbenzene and xylenes, along with continuous CO and PM 2.5 measurements were utilised. The measurements were made indoors and outdoors in 27 dwellings; 15 Near Road (<50 m from a major road) and 12 Far Road (>300 m from a major road). Dwellings were sampled for one week each in Winter/Spring 2008 and Summer/Autumn 2009, over an eight month period. Analysis of 7-day measurements showed that NO 2 and toluene were elevated at the 5% significance level both indoors and outdoors at Near Road Dwellings compared to Far Road Dwellings. Indoor/Outdoor (I/O) ratios of NO 2 and toluene were not significantly different between Near and Far Road dwellings giving no evidence of any anomalous dominant indoor source for NO 2 and toluene in Near Road dwellings. Indoor NO 2 was significantly correlated to gas stovetop and oven use in both Near and Far Road dwellings. In the absence of gas cooking, indoor NO 2 was elevated in Near Road dwellings relative to Far Road dwellings by approximately 4 ppb and this can be attributed to infiltration of outdoor air. I/O ratios for NO 2 were <1 for Near and Far Road dwellings, indicating that outdoor NO 2, and hence roadway emissions can potentially contribute a significant proportion to the indoor NO 2 concentration. Mean toluene I/O ratios were >2 indicating that indoor sources dominate with minor contribution from outdoors. Hence the relative contribution of roadways to indoor NO 2 is potentially greater than the relative contribution of roadways to indoor toluene. Findings elsewhere suggest that a similar outdoor enhancement of traffic related NO 2 (˜5 ppb) increases risk of lung cancer and childhood asthma ( Brauer et al., 2000; Nyberg et al., 2000). A simple

  19. Radon 222 from the ocean surface

    SciTech Connect

    Duenas, C.; Fernandez, M.C.; Martinez, M.P.

    1983-10-20

    The flux of /sup 222/Rn from shallow water off the bay of Malaga has been measured by the accumulation method. The mean value of 67 atoms m/sup -2/ s/sup -1/ was obtained compared with a range of values from 11 to 116 atoms m/sup -2/ s/sup -1/ calculated from near-surface /sup 222/Rn profiles in seawater obtained by other investigators. Quanititative relations between the flux of /sup 222/Rn and /sup 222/Rn concentrations in surface water and the temperature of seawater were found. A correlation was also found between the flux of /sup 222/Rn and the wind speed at the moment of taking the sample.

  20. Using ²²²Rn as a naturally occurring tracer to estimate NAPL contamination in an aquifer.

    PubMed

    Yoon, Yoon Yeol; Koh, Dong Chan; Lee, Kil Yong; Cho, Soo Young; Yang, Jae Ha; Lee, Kang Kun

    2013-11-01

    The naturally occurring radioisotope (222)Rn was used as a partitioning tracer to evaluate the presence and amount of a non-aqueous phase liquid (NAPL) in an aquifer. The batch experiment results of a diesel contaminated soil showed that the emanation rate of (222)Rn decreased to 31%, relative to a background rate. Batch experiment results of water contaminated by gasoline, diesel, PCE and TCE were similar. A field study to examine TCE contamination was conducted using 54 groundwater samples in Wonju city, Republic of Korea. Estimates of TCE contamination ranged from <0.001 mg/L to 14.3mg/L, and (222)Rn concentrations ranged from 1.89 Bq/L to 444. Results of (222)Rn analysis showed that TCE contamination was mainly restricted to an asphalt laboratory area and that the (222)Rn values of a NAPL-contaminated aquifer were correlated with TCE analytical results. PMID:23602707

  1. A study of atmospheric radon gas concentrations in water extraction wells of Hamadan, western Iran.

    NASA Astrophysics Data System (ADS)

    Gillmore, Gavin; Jabari Vasal, Naghi

    2010-05-01

    It is well known that half of the radiation received by humans is due to the presence of radon (222Rn) in the built environment. As part of a project measuring indoor radon in Hamadan, western Iran, a survey was undertaken of atmospheric radon in 28 wells in the region using a Sarad Doseman. Specific geological features of this settlement include highly permeable alluvial fan deposits which result in radon being released to the atmosphere. The observed radon concentrations in well shafts(between 1,000 Bq m3 and 36,600 Bq m3) show considerable variability both in space and time. One aspect of this study was to also assess whether there was a relationship between the depth of a well and the measured atmospheric radon concentration. The importance of such measurements in this region is highlighted by the fact that radon levels in homes in Hamadan are probably greatly influenced by the porous nature of this underlying geology and its use as a water reservoir / conduit through the application of qanat technology.

  2. Radon daughter carousel: An automated instrument for measuring indoor concentrations of 218Po, 214Pb, and 214Bi

    NASA Astrophysics Data System (ADS)

    Nazaroff, William W.

    1983-09-01

    A microprocessor-controlled instrument for measuring the concentrations of radon progeny in indoor air is described. The measurement technique is based on alpha spectroscopy and uses two counting intervals following a sampling period during which radon progeny are collected on a filter. The counting intervals are selected to provide optimal precision for measuring 222Rn progeny for fixed total measurement times ranging from 30 to 60 min: concentrations as low as 0.5 pCi/1 can be measured with less than 20% uncertainty in 45 min. The instrument can also be used to estimate the potential alpha energy concentration of 220Rn decay products. The device operates under the control of a computer or a data terminal and functions for week-long periods between filter changes. The user can specify the sampling- and counting-interval timing over a wide range and select from among several operating modes. A number of performance tests are also described indicating that for typical indoor concentrations the measurement uncertainty is dominated by counting statistics.

  3. Comparison of Ambient Radon Concentrations in Air in the Northern Mojave Desert from Continuous and Integrating Instruments

    SciTech Connect

    David S. Shafer; David McGraw; Lynn H. Karr; Greg McCurdy; Tammy L. Kluesner; Karen J. Gray; Jeffrey Tappen

    2010-05-18

    As part of a program to characterize and baseline environmental parameters, ambient radon-222 (Rn) monitoring was conducted in the rural community of Amargosa Valley, NV, the closest community to Yucca Mountain. Passive integrating and continuous Rn monitoring instruments were deployed adjacent to the Community Environmental Monitoring Program (CEMP) station in Amargosa Valley. The CEMP station provided real-time ambient gamma exposure and meteorological data used to correct the integrated Rn measurements, verified the meteorological data collected by the continuous Rn monitoring instrument, and for provided instrumentation for evaluating the relationships between meteorological conditions and Rn concentrations. Hourly Rn concentrations in air measured by the continuous Rn monitoring instrument (AlphaGUARD®) were compared to the average hourly values for the integrating Rn measurements (E-PERM®) by dividing the total Rn measurements by the number of hours the instruments were deployed. The results of the comparison indicated that average hourly ambient Rn concentrations as measured by both methods ranged from 0.2 to 0.4 pico-curies per liter of air. Ambient Rn values for the AlphaGUARD exhibited diurnal variations. When Rn concentrations were compared with measurements of temperature (T), barometric pressure, and relative humidity, the correlation (inversely) was highest with T, albeit weakly.

  4. Short-term radon activity concentration changes along the Underground Educational Tourist Route in the Old Uranium Mine in Kletno (Sudety Mts., SW Poland).

    PubMed

    Fijałkowska-Lichwa, Lidia

    2014-09-01

    Short-term (222)Rn activity concentration changes along the Underground Educational Tourist Route in the Old Uranium Mine in Kletno were studied, based on continuous measurements conducted between 16 May 2008 and 15 May 2010. The results were analysed in the context of numbers of visitors arriving at the facility in particular seasons and the time per day spent inside by staff and visitors. This choice was based on partially published earlier findings (Fijałkowska-Lichwa and Przylibski, 2011). Results for the year 2009 were analysed in depth, because it is the only period of observation covering a full calendar year. The year 2009 was also chosen for detailed analysis of short-term radon concentration changes, because in each period of this year (hour, month, season) fluctuations of noted values were the most visible. Attention has been paid to three crucial issues linked to the occurrence and behaviour of radon and to the radiological protection of workers and visitors at the tourist route in Kletno. The object of study is a complex of workings in a former uranium mine situated within a metamorphic rock complex in the most radon-prone area in Poland. The facility has been equipped with a mechanical ventilation system, which is turned on after the closing time and at the end of the working day for the visitor service staff, i.e. after 6 p.m. Short-term radon activity concentration changes along the Underground Educational Tourist Route in the Old Uranium Mine in Kletno are related to the activity of the facility's mechanical ventilation. Its inactivity in the daytime results in the fact that the highest values of (222)Rn activity concentration are observed at the time when the facility is open to visitors, i.e. between 10 a.m. and 6 p.m. The improper usage of the mechanical ventilation system is responsible for the extremely unfavourable working conditions, which persist in the facility for practically all year. The absence of appropriate radiological protection

  5. 'Radon Concentration Survey in Inner Rooms from Deputy Chamber and National Congress-Brasilia/DF'

    SciTech Connect

    Nicoli, Ieda Gomes; Cardozo, Katia Maria; Azevedo Gouvea, Vandir de

    2008-08-07

    Radon gas has been monitored in many environments such as rural and urban houses, high natural radioactivity areas and underground mining regions. Nevertheless few data are reported in literature about studies in state buildings. So we get in touch with these buildings managers, where work the Deputy Chamber and the National Congress in Brasilia--DF, in order to obtain radon data in these state buildings, so representative for brazilian people. In order to make a preliminary scanning of radon concentration in these buildings, it was put in selected points, radon nuclear track passive detectors type SSNTD, specifically polycarbonate Lexan, which were exposed for periods from two to five months. Afterwards they were sent to Nuclear Engineering Institute in Rio de Janeiro for analysis of {sup 222}Rn contents. Derived values, whose average value was about 73 Bq/m{sup 3}, were all under maximum permissible limits for radon 200 Bq/m{sup 3}, established by International Comission on Radiological Protection--ICRP 65, for inner environments of houses and state buildings. This work has been coordinated by CNEN Office in Braselia with effective participation of Nuclear Engineering Institute from CNEN--RJ, that has worked since beginning of april 2004, supplying and analysing radon detectors.

  6. EFFECTS OF NATURAL AND FORCED BASEMENT VENTILATION ON RADON LEVELS IN SINGLE FAMILY DWELLINGS

    EPA Science Inventory

    The report gives, for the first time, results of an extensive study of the effect of ventilation on radon concentrations and radon entry rate in a single-family dwelling. Measurements of radon concentrations, building dynamics, and environmental parameters made in Princeton Unive...

  7. Influences of vertical transport and scavenging on aerosol particle surface area and radon decay product concentrations at the Jungfraujoch (3454 m above sea level)

    NASA Astrophysics Data System (ADS)

    Lugauer, M.; Baltensperger, U.; Furger, M.; GäGgeler, H. W.; Jost, D. T.; Nyeki, S.; Schwikowski, M.

    2000-08-01

    Concentrations of the aerosol particle surface area (SA) and aerosol-attached radon decay products 214Pb and 212Pb have been measured by means of an aerosol and a radon epiphaniometer at the Jungfraujoch research station (JFJ; 3454 m above sea level, Switzerland). These parameters exhibit a pronounced seasonal cycle with minimum values in winter and maximum values in summer. In summer, pronounced diurnal variations with a maximum at 1800 LST are often present. Highest concentrations and most pronounced diurnal variations occur during anticyclonic weather conditions in summer. Thermally driven vertical transport over alpine topography is responsible for this observation. During this synoptic condition, concentrations vary greatly with the 500 hPa wind direction, exhibiting low concentrations for NW-N winds and high concentrations for weak or S-SW winds. Lead-214 and SA are highly correlated during anticyclonic conditions, indicating transport equivalence of the gaseous 214Pb precursor, 222Rn, and of aerosol particles. When cyclonic lifting is the dominant vertical transport, wet scavenging of aerosol particles can explain the weak correlation of 214Pb and SA. This conclusion is corroborated by the 214Pb/SA ratio, being twice as high during cyclonic than during anticyclonic conditions. Lead-212 is a tracer for the influence of surface contact on a local scale due to its short lifetime of 15.35 hours. The analysis of this parameter suggests that high-alpine surfaces play an important role in thermally driven transport to the JFJ.

  8. Factors affecting dwell times on digital displaying

    NASA Technical Reports Server (NTRS)

    Williams, A. J.; Harris, R. L., Sr.

    1985-01-01

    A series of exploratory tests were conducted to investigate the effects of advanced display formats and display media on pilot scanning behavior using Langley's oculometer, a desktop flight simulator, a conventional electro-mechanical meter, and various digital displays. The primary task was for the test subject to maintain level flight, on a specific course heading, during moderate turbulence. A secondary task of manually controlling the readout of a display was used to examine the effects of the display format on a subject's scan behavior. Secondary task scan parameters that were evaluated were average dwell time, dwell time histograms, and number of dwells per meter change. The round dial meter demonstrated shorter dwell times and fewer dwells per meter change than the digital displays. The following factors affected digital display scanning behavior: (1) the number of digits; (2) the update rate of the digits; (3) the display media; and (4) the character font. The size of the digits used in these tests (0.28 to 0.50 inches) did not affect scan behavior measures.

  9. Tunable dwell time in gated silicene nanostructures

    NASA Astrophysics Data System (ADS)

    Zhu, B. S.; Wang, Y.; Lou, Y. Y.

    2016-01-01

    Residing on the gate-tunable electronic properties of silicene, we have systematically examined the dwell time for quantum tunneling through the single and multiple-gated silicene nanostructures. It is shown that unlike the graphene, superluminal tunneling is observable even at the normal incidence due to the sizeable spin-orbit gap of silicene. Together with its field-tunable bandgap, we show that this superluminal tunneling can be further flexibly switched on and off via electric mean. By simulating the dwell time through the symmetric and asymmetric double barrier structures, it is also shown here that the dwell time displays the distinct dependence on the former and latter barrier profiles. Those observations provide some favorable strategies to experimentally examine and fundamentally understand the time-dependent aspect of tunneling in solid state nanosystems.

  10. Estimation of Groundwater Radon in North Carolina Using Land Use Regression and Bayesian Maximum Entropy.

    PubMed

    Messier, Kyle P; Campbell, Ted; Bradley, Philip J; Serre, Marc L

    2015-08-18

    Radon ((222)Rn) is a naturally occurring chemically inert, colorless, and odorless radioactive gas produced from the decay of uranium ((238)U), which is ubiquitous in rocks and soils worldwide. Exposure to (222)Rn is likely the second leading cause of lung cancer after cigarette smoking via inhalation; however, exposure through untreated groundwater is also a contributing factor to both inhalation and ingestion routes. A land use regression (LUR) model for groundwater (222)Rn with anisotropic geological and (238)U based explanatory variables is developed, which helps elucidate the factors contributing to elevated (222)Rn across North Carolina. The LUR is also integrated into the Bayesian Maximum Entropy (BME) geostatistical framework to increase accuracy and produce a point-level LUR-BME model of groundwater (222)Rn across North Carolina including prediction uncertainty. The LUR-BME model of groundwater (222)Rn results in a leave-one out cross-validation r(2) of 0.46 (Pearson correlation coefficient = 0.68), effectively predicting within the spatial covariance range. Modeled results of (222)Rn concentrations show variability among intrusive felsic geological formations likely due to average bedrock (238)U defined on the basis of overlying stream-sediment (238)U concentrations that is a widely distributed consistently analyzed point-source data. PMID:26191968

  11. Effective Dose Radon 222 of the Tap Water in Children and Adults People; Minab City, Iran.

    PubMed

    Fakhri, Yadolah; Kargosha, Morteza; Langarizadeh, Ghazaleh; Zandsalimi, Yahya; Rasouli Amirhajeloo, Leila; Moradi, Mahboobeh; Moradi, Bigard; Mirzaei, Maryam

    2016-04-01

    (222)Rn is a radioactive, odorless, and colorless element which has a half-life of 3.83 days. One of (222)Rn main resources are Groundwater (wells, springs, etc.). Hence, the use of groundwater with high concentration of (222)Rn can increase the risk of lung and stomach cancers. Concentration of (222)Rn in tap water of Minab city in two temperatures 5 and 15 ºC was measured by radon meter model RTM1668-2. The effective dose was calculated by equations proposed by UNSCEAR. Geometric mean concentration of (222)Rn in drinking water was found to be 0.78±0.06 and 0.46±0.04 Bq/l at 5 and 15 ̊C (p value<0.05), respectively. The effective doses were 0.006 and 0.003 mSv/y for adults, and 0.011 and 0.007 mSv/y for the children, respectively (p value<0.05). Besides, the effective dose for adult through inhaling (222)Rn at 5 and 15 ̊C were estimated 0.0021 and 0.0012mSv/y, respectively. Geometric mean concentration in (222)Rn drinking water and effective dose received from drinking water and inhalation of (222)Rn is lower than WHO and EPA standard limits. Increasing temperature of drinking water will decrease the effective dose received. Annual Effective dose received from inhalation and consumption of (222)Rn in drinking water in children is more than adults. PMID:26573047

  12. Effective Dose Radon 222 of the Tap Water in Children and Adults People; Minab City, Iran

    PubMed Central

    Fakhri, Yadolah; Kargosha, Morteza; Langarizadeh, Ghazaleh; Zandsalimi, Yahya; Amirhajeloo, Leila Rasouli; Moradi, Mahboobeh; Moradi, Bigard; Mirzaei, Maryam

    2016-01-01

    222Rn is a radioactive, odorless, and colorless element which has a half-life of 3.83 days. One of 222Rn main resources are Groundwater (wells, springs, etc.). Hence, the use of groundwater with high concentration of 222Rn can increase the risk of lung and stomach cancers. Concentration of 222Rn in tap water of Minab city in two temperatures 5 and 15 ºC was measured by radon meter model RTM1668-2. The effective dose was calculated by equations proposed by UNSCEAR. Geometric mean concentration of 222Rn in drinking water was found to be 0.78±0.06 and 0.46±0.04 Bq/l at 5 and 15 °C (p value<0.05), respectively. The effective doses were 0.006 and 0.003 mSv/y for adults, and 0.011 and 0.007 mSv/y for the children, respectively (p value<0.05). Besides, the effective dose for adult through inhaling 222Rn at 5 and 15 °C were estimated 0.0021 and 0.0012mSv/y, respectively. Geometric mean concentration in 222Rn drinking water and effective dose received from drinking water and inhalation of 222Rn is lower than WHO and EPA standard limits. Increasing temperature of drinking water will decrease the effective dose received. Annual Effective dose received from inhalation and consumption of 222Rn in drinking water in children is more than adults. PMID:26573047

  13. Optimizing peritoneal dialysis prescription for volume control: the importance of varying dwell time and dwell volume.

    PubMed

    Fischbach, Michel; Zaloszyc, Ariane; Schaefer, Betti; Schmitt, Claus Peter

    2014-08-01

    Not only adequate uremic toxin removal but also volume control is essential in peritoneal dialysis (PD) to improve patient outcome. Modification of dwell time impacts on both ultrafiltration (UF) and purification. A short dwell favors UF but preferentially removes small solutes such as urea. A long dwell favors uremic toxin removal but also peritoneal fluid reabsorption due to the time-dependent loss of the crystalloid osmotic gradient. In particular, the long daytime dwell in automated PD may result in significant water and sodium reabsorption, and in such cases icodextrin should be considered. Increasing dwell volume favors the removal of solutes such as sodium due to the increased volume of diffusion and the recruitment of peritoneal surface area. A very large fill volume with too high an intraperitoneal pressure (IPP) may, however, result in back-filtration and thus reduced UF and sodium clearance. Based on these principles and the individual transport and pressure kinetics obtained from peritoneal equilibration tests and IPP measurements, we suggest combining short dwells with a low fill volume to favor UF with long dwells and a large fill volume to favor solute removal. Results from a recent randomized cross-over trial and earlier observational data in children support this concept: the absolute UF and UF relative to the administered glucose increased and solute removal and blood pressure improved. PMID:23903692

  14. Development of an Anisotropic Geological-Based Land Use Regression and Bayesian Maximum Entropy Model for Estimating Groundwater Radon across Northing Carolina

    NASA Astrophysics Data System (ADS)

    Messier, K. P.; Serre, M. L.

    2015-12-01

    Radon (222Rn) is a naturally occurring chemically inert, colorless, and odorless radioactive gas produced from the decay of uranium (238U), which is ubiquitous in rocks and soils worldwide. Exposure to 222Rn is likely the second leading cause of lung cancer after cigarette smoking via inhalation; however, exposure through untreated groundwater is also a contributing factor to both inhalation and ingestion routes. A land use regression (LUR) model for groundwater 222Rn with anisotropic geological and 238U based explanatory variables is developed, which helps elucidate the factors contributing to elevated 222Rn across North Carolina. Geological and uranium based variables are constructed in elliptical buffers surrounding each observation such that they capture the lateral geometric anisotropy present in groundwater 222Rn. Moreover, geological features are defined at three different geological spatial scales to allow the model to distinguish between large area and small area effects of geology on groundwater 222Rn. The LUR is also integrated into the Bayesian Maximum Entropy (BME) geostatistical framework to increase accuracy and produce a point-level LUR-BME model of groundwater 222Rn across North Carolina including prediction uncertainty. The LUR-BME model of groundwater 222Rn results in a leave-one out cross-validation of 0.46 (Pearson correlation coefficient= 0.68), effectively predicting within the spatial covariance range. Modeled results of 222Rn concentrations show variability among Intrusive Felsic geological formations likely due to average bedrock 238U defined on the basis of overlying stream-sediment 238U concentrations that is a widely distributed consistently analyzed point-source data.

  15. Passive Measurements of Thoron and its Progeny in some Dwellings in Ireland

    SciTech Connect

    Choncubhair, Orlaith Ni; Laughlin, James Mc; Tokonami, Shinji

    2008-08-07

    In this paper, an account is given of the development, calibration and field use of a passive alpha track detector sensitive to thoron as well as to radon. No database of thoron and thoron progeny concentrations in dwellings in Ireland exists and, as a result, the level of exposure of the Irish population to thoron and its progeny is unknown. As an initial or pilot stage in establishing such a data base measurements of thoron and thoron progeny concentrations (the latter expressed in Equilibrium Equivalent Thoron Concentration (EETC)) were made in 40 randomly chosen Irish dwellings. The EETC measurements were made using a passive thoron progeny deposition rate monitor designed and supplied by NIRS (Japan). In addition standard unmodified SSI passive radon detectors were used to measure radon in these dwellings. The measured thoron concentrations ranged from below the level of detection to 154 Bq/m{sup 3} while the radon gas ranged from 15 to 179 Bq/m{sup 3}. The thoron progeny EETC values for these dwellings ranged from 0.03 to 7.7 Bq/m{sup 3}. An account is also given of the dosimetric implications of these measurements.

  16. 12 CFR 141.25 - Single-family dwelling.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 1 2014-01-01 2014-01-01 false Single-family dwelling. 141.25 Section 141.25... AFFECTING FEDERAL SAVINGS ASSOCIATIONS § 141.25 Single-family dwelling. The term single-family dwelling means a structure designed for residential use by one family, or a unit so designed, whose owner...

  17. 12 CFR 541.25 - Single-family dwelling.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Single-family dwelling. 541.25 Section 541.25... AFFECTING FEDERAL SAVINGS ASSOCIATIONS § 541.25 Single-family dwelling. The term single-family dwelling means a structure designed for residential use by one family, or a unit so designed, whose owner...

  18. 12 CFR 541.25 - Single-family dwelling.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 6 2014-01-01 2012-01-01 true Single-family dwelling. 541.25 Section 541.25... AFFECTING FEDERAL SAVINGS ASSOCIATIONS § 541.25 Single-family dwelling. The term single-family dwelling means a structure designed for residential use by one family, or a unit so designed, whose owner...

  19. 12 CFR 541.25 - Single-family dwelling.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 5 2011-01-01 2011-01-01 false Single-family dwelling. 541.25 Section 541.25... AFFECTING FEDERAL SAVINGS ASSOCIATIONS § 541.25 Single-family dwelling. The term single-family dwelling means a structure designed for residential use by one family, or a unit so designed, whose owner...

  20. 12. SOUTHWEST VIEW OF FIRST CENTRE FAMILY DWELLING HOUSE, LATER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. SOUTHWEST VIEW OF FIRST CENTRE FAMILY DWELLING HOUSE, LATER FARMER DEACON'S SHOP, WITH SECOND CENTRE FAMILY DWELLING HOUSE IN BACKGROUND - Shaker Centre Family Dwelling House (First), North side of Village Road, North of U.S. Route 68 & State Route 33 intersection, Shakertown, Mercer County, KY

  1. 12 CFR 541.25 - Single-family dwelling.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 6 2012-01-01 2012-01-01 false Single-family dwelling. 541.25 Section 541.25... AFFECTING FEDERAL SAVINGS ASSOCIATIONS § 541.25 Single-family dwelling. The term single-family dwelling means a structure designed for residential use by one family, or a unit so designed, whose owner...

  2. 12 CFR 141.25 - Single-family dwelling.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 1 2013-01-01 2013-01-01 false Single-family dwelling. 141.25 Section 141.25... AFFECTING FEDERAL SAVINGS ASSOCIATIONS § 141.25 Single-family dwelling. The term single-family dwelling means a structure designed for residential use by one family, or a unit so designed, whose owner...

  3. 12 CFR 541.25 - Single-family dwelling.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 6 2013-01-01 2012-01-01 true Single-family dwelling. 541.25 Section 541.25... AFFECTING FEDERAL SAVINGS ASSOCIATIONS § 541.25 Single-family dwelling. The term single-family dwelling means a structure designed for residential use by one family, or a unit so designed, whose owner...

  4. 12 CFR 141.25 - Single-family dwelling.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 1 2012-01-01 2012-01-01 false Single-family dwelling. 141.25 Section 141.25... AFFECTING FEDERAL SAVINGS ASSOCIATIONS § 141.25 Single-family dwelling. The term single-family dwelling means a structure designed for residential use by one family, or a unit so designed, whose owner...

  5. Curriculum Making as the Enactment of Dwelling in Places

    ERIC Educational Resources Information Center

    Ross, Hamish; Mannion, Greg

    2012-01-01

    This article uses an account of dwelling to interrogate the concept of curriculum making. Tim Ingold's use of dwelling to understand culture is productive here because of his implicit and explicit interest in intergenerational learning. His account of dwelling rests on a foundational ontological claim--that mental construction and representation…

  6. Experimental setup for radon exposure and first diffusion studies using gamma spectroscopy

    NASA Astrophysics Data System (ADS)

    Maier, Andreas; van Beek, Patrick; Hellmund, Johannes; Durante, Marco; Schardt, Dieter; Kraft, Gerhard; Fournier, Claudia

    2015-11-01

    In order to measure the uptake and diffusion of 222Rn in biological material, an exposure chamber was constructed where cell cultures, biological tissues and mice can be exposed to 222Rn-activities similar to therapy conditions. After exposure, the material is transferred to a gamma spectrometer and the decay of 214Pb and 214Bi is analyzed. From the time kinetics of these decays the total amount of the initial 222Rn concentration can be calculated. In this paper the design and construction as well as first test measurements are reported.

  7. Single Roller-to-Cam Indexing Mechanisms Providing Two Maximized Dwells: Determination of Cam Pitch Profile for Optimal Designs

    NASA Astrophysics Data System (ADS)

    Tripathi, K. S.

    2015-04-01

    The view point of present research paper is concentrated on a part of a systematic scientific investigation of the mechanical possibilities of generating non-uniform full-rotational output motion with intermittent motion as the most important special case. The paper develops a geometrical construction of the cam pitch profile for optimal designs for single roller-to-cam indexing mechanism providing either two unequal maximum extent dwells with equal indexing angles (and unequal indexing periods) or two equal maximized dwells with unequal indexing angles (and equal indexing periods). Placement of the two dwells in the same half of the motion cycle gives very small periods; very high accelerations; and poor radius of curvature in the transition portion. Hence this paper considers optimal motion diagrams for the case of two dwells placed in different halves of the motion cycle and using the principle of kinematic inversion with intuitive conviction very tactically determines the cam pitch profile.

  8. Recoil-deposited Po-210 in radon dwellings

    SciTech Connect

    Samuelsson, C.

    1990-12-31

    Short-lived decay products of Rn-222 plate out on all surfaces in a house containing radon gas. Following the subsequent alpha decays of the mother nuclei, the daughter products Pb-214 and Pb-210 are superficially and permanently absorbed. Due to its long half-life (22 y) the activity of absorbed Pb-210 accumulates in the surface. The activity of Pb-210, or its decay products, can thus reflect the past randon daughter and plate-out history of a house over several decades. Our results and experience from measurements of Po-210 and Rn-222 in 22 dwellings will be presented. In these studies the Po-210 surface activity of one plane glass sheet per dwelling (window panes were not used) has been determined and compared with the period of exposure times the mean radon concentration measured over a two-month period. Considering the large uncertainty in the integrated radon exposure estimate the surface {sup 210}Po correlates well (r=0.73) with the accumulated radon exposure. The {sup 210}Po activity of the glass samples has been measured non-destructively using an open-flow pulse ionization chamber and this detector has also been successfully applied in field exercises.

  9. Measurements of airborne 212Pb and 220Rn at varied indoor locations within the United States.

    PubMed

    Schery, S D

    1985-12-01

    Measurements have been made at varied locations within the United States comparing the concentration of 212Pb in air with that of the progeny of 222Rn to see if 212Pb is typically a significant contributor to indoor radioactivity. Auxiliary measurements were made comparing 220Rn with 222Rn. In terms of potential alpha-particle energy, 212Pb is significant (the ratio of its contribution to the combined contribution of 218Po, 214Pb, and 214Bi averaged about 0.6) and may warrant greater consideration as a component of indoor radioactivity. Correlations were found between the concentration of 220Rn progeny and 222Rn progeny, and the concentration of 220Rn and 222Rn. Environmental factors such as transport pathways and ventilation rates which exert a common influence on the concentrations of airborne isotopes provide a possible explanation for these correlations. PMID:4077512

  10. Hold it! Memory affects attentional dwell time.

    PubMed

    Parks, Emily L; Hopfinger, Joseph B

    2008-12-01

    The allocation of attention, including the initial orienting and the subsequent dwell time, is affected by several bottom-up and top-down factors. How item memory affects these processes, however, remains unclear. Here, we investigated whether item memory affects attentional dwell time by using a modified version of the attentional blink (AB) paradigm. Across four experiments, our results revealed that the AB was significantly affected by memory status (novel vs. old), but critically, this effect depended on the ongoing memory context. Specifically, items that were unique in terms of memory status demanded more resources, as measured by a protracted AB. The present findings suggest that a more comprehensive understanding of memory's effects on attention can be obtained by accounting for an item's memorial context, as well as its individual item memory strength. Our results provide new evidence that item memory and memory context play a significant role in the temporal allocation of attention. PMID:19001579

  11. Cylindrical optic figuring dwell time optimization

    NASA Astrophysics Data System (ADS)

    Waluschka, Eugene

    2000-11-01

    The Constellation-X, grazing incidence, x-ray telescope may be fabricated from replicated segments. A series of mandrels will serve as the 'masters' in the replication processes. Diamond turning (milling) followed by abrasive figuring followed by a super polishing are the steps currently envisioned in making just one (of many) mandrel. The abrasive figuring of a mandrel is accomplished by moving a grinding tool along a helical path on this almost cylindrical surface. The measurement of the surface is, however, performed along 'axial' scan lines which intercept this helical path. This approach to figuring and measuring permits a relatively simple scheme to be implemented for the determination of the optimal dwell times of the figuring tool. These optimal dwell times are determined by a deconvolution which approaches the problem in a linear programming context and uses the Simplex Method. The approach maximizes the amount of material removed at any point subject to inequality constraints. The effects of using these 'optimum' dwell times is to significantly improve the tools effectiveness at removing the higher spatial frequencies while staying (strictly) within the bounds and constraints imposed by the hardware. In addition, the ringing at the edges of the optic, frequently present in deconvolution problems, is completely eliminated.

  12. A study of environmental radioactivity measurements in the Samsun province, Turkey.

    PubMed

    Kucukomeroglu, B; Maksutoglu, F; Damla, N; Cevik, U; Celebi, N

    2012-12-01

    This study was concerned with the measurement of natural and artificial radionuclides in soil samples and indoor radon concentrations in the Samsun province, Turkey. In soil samples, the values of individual mean activity of (226)Ra, (232)Th, (40)K and (137)Cs radionuclides were found to be 31, 22, 341 and 16 Bq kg(-1), respectively. The radiological parameters, such as the absorbed dose rate in air, the annual effective dose (AED) and excess lifetime cancer risk, were calculated. Indoor radon measurements were carried out with CR-39-based radon dosemeters at 127 dwellings in the Samsun province. The mean annual (222)Rn activity was found to be 106 Bq m(-3) (equivalent to an AED of 1.88 mSv). The seasonal variation of (222)Rn activity shows that maximum levels are observed in the winter, while minimum levels are observed in the summer. The mean lifetime fatality risk for the studied area was estimated at 1.45×10(-4). The results obtained did not significantly differ from those obtained in other parts of the country. PMID:22619352

  13. [The contents of radon in deep borehole water of hydro-geological region of Gdańsk].

    PubMed

    Pachocki, K A; Gorzkowski, B; Rózycki, Z; Majle, T

    1999-01-01

    Radon 222Rn in deep borehole water of Gdańsk Hydrogeological Region has been quantitative determined. This region is located in east part of Gdańsk Voivodship and in west part of Elblag Voivodship including Zuławy. The measurements were performed using alpha liquid scintillation counting method. Only in some case the concentrations of 222Rn in investigated samples exceed recommended limit 11 Bq/l. PMID:10523933

  14. A Universe on which to dwell

    NASA Astrophysics Data System (ADS)

    Atkinson, Marea

    2011-06-01

    The artworks The Cosmic Garden and To Dwell Upon the Universe created for the exhibition Astronomical Inspirations, at the Salle Miró, UNESCO Headquarters, for the launch of the International Year of Astronomy reflect upon the unfolding human perception and relationship with the cosmos and speculate on the nature of space expressed in printmaking via a study of astronomical phenomena, symbolism in visual and scientific artefacts and theories. The work overlaps between the printed image, the constructed print, the artist book and installation.

  15. Influence of Asian outflow on Rishiri Island, northernmost Japan: Application of radon as a tracer for characterizing fetch regions and evaluating a global 3D model

    NASA Astrophysics Data System (ADS)

    Zhu, Chunmao; Yoshikawa-Inoue, Hisayuki; Matsueda, Hidekadzu; Sawa, Yosuke; Niwa, Yosuke; Wada, Akira; Tanimoto, Hiroshi

    2012-04-01

    Atmospheric 222Rn was monitored from December 2008 to November 2010 on Rishiri Island (45°07‧N, 141°12‧E), northernmost Japan. Seasonal 222Rn variation was characterized by high concentrations from November to February and low concentrations from May to July, caused by the alternation of continental and maritime fetch regions. 222Rn tracer and back trajectory cluster analyses indicated that the predominant continental fetch region was southeastern Siberia and northeastern China. 222Rn emitted from China and South Korea, whose economies are growing rapidly, did not significantly affect the Rishiri site. The major maritime fetch region was the Sea of Okhotsk and the Bering Sea. A global three-dimensional model (NICAM-TM) accurately simulated 222Rn concentrations on Rishiri Island and in the seasonal fetch regions. The time series of 222Rn data will make it possible to evaluate the sources and sinks of atmospheric greenhouse gases being monitored at Rishiri Island, which complements other sites in the Asia-Pacific rim region, and to validate model simulations used to examine trans-boundary air pollution.

  16. 24 CFR 203.38 - Location of dwelling.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Location of dwelling. 203.38 Section 203.38 Housing and Urban Development Regulations Relating to Housing and Urban Development... § 203.38 Location of dwelling. At the time a mortgage is insured there must be located on the...

  17. 24 CFR 203.38 - Location of dwelling.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false Location of dwelling. 203.38 Section 203.38 Housing and Urban Development Regulations Relating to Housing and Urban Development... § 203.38 Location of dwelling. At the time a mortgage is insured there must be located on the...

  18. 24 CFR 203.38 - Location of dwelling.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Location of dwelling. 203.38 Section 203.38 Housing and Urban Development Regulations Relating to Housing and Urban Development... § 203.38 Location of dwelling. At the time a mortgage is insured there must be located on the...

  19. Effects of mining-derived metals on riffle-dwelling benthic fishes in Southeast Missouri, USA

    USGS Publications Warehouse

    Allert, A.L.; Fairchild, J.F.; Schmitt, C.J.; Besser, J.M.; Brumbaugh, W.G.; Olson, S.J.

    2009-01-01

    We studied the ecological effects of mining-derived metals on riffle-dwelling benthic fishes at 16 sites in the Viburnum Trend lead-zinc mining district of southeast Missouri. Fish community attributes were compared to watershed features and to physical and chemical variables including metal concentrations in sediment pore water and fish. Ozark sculpin (Cottus hypselurus), rainbow darter (Etheostoma caeruleum), Ozark madtom (Noturus albater), and banded sculpin (Cottus carolinae) were the most abundant fishes collected. Species richness and density of riffle-dwelling benthic fishes were negatively correlated with metal concentrations in pore water and in fish. Sculpin densities were also negatively correlated with metal concentrations in pore water and in fish, but positively correlated with distance from mines and upstream watershed area. These findings indicate that metals associated with active lead-zinc mining adversely affect riffle-dwelling benthic fishes downstream of mining areas in the Viburnum Trend. Sculpins may be useful as a sentinel species for assessing mining-related impacts on fish communities.

  20. Low cycle dwell time fatigue in Ti-6242

    SciTech Connect

    Kassner, M.E.; Faber, R.; Li, X.; Ge, Y.; Kosaka, Y.; Bristow, B.; Reichman, S.H.; Hall, J.A.

    1999-07-01

    Ambient temperature low cycle dwell time and conventional low cycle fatigue tests were performed on Ti-6Al-2Sn-4Zr-2Mo (Ti-6242). Specimens were solution annealed at various temperatures below the beta transus to control the volume fraction of primary alpha. The influence of the changes in primary alpha phase on low cycle dwell time fatigue life (DLCF) were determined and compared to the conventional low cycle fatigue (LCF) properties of the alloy. A dwell significantly decreased the number of cycles to failure. Increasing primary alpha associated with lower solution temperatures significantly increased susceptibility to low cycle dwell time fatigue although this effect, and DLCF in general, diminished with decreasing stress. It is believed that the susceptibility to dwell fatigue may be associated with ambient temperature, time-dependent, cyclic (creep) plasticity.

  1. Filter model based dwell time algorithm for ion beam figuring

    NASA Astrophysics Data System (ADS)

    Li, Yun; Xing, Tingwen; Jia, Xin; Wei, Haoming

    2010-10-01

    The process of Ion Beam Figuring (IBF) can be described by a two-dimensional convolution equation which including dwell time. Solving the dwell time is a key problem in IBF. Theoretically, the dwell time can be solved from a two-dimensional deconvolution. However, it is often ill-posed]; the suitable solution of that is hard to get. In this article, a dwell time algorithm is proposed, depending on the characters of IBF. Usually, the Beam Removal Function (BRF) in IBF is Gaussian, which can be regarded as a headstand Gaussian filter. In its stop-band, the filter has various filtering abilities for various frequencies. The dwell time algorithm proposed in this article is just based on this concept. The Curved Surface Smooth Extension (CSSE) method and Fast Fourier Transform (FFT) algorithm are also used. The simulation results show that this algorithm is high precision, effective, and suitable for actual application.

  2. [Home and dwelling arrangements in old age].

    PubMed

    Dapp, Ulrike; von Renteln-Kruse, Wolfgang

    2015-10-01

    The increase of life expectancy provides the unique opportunity to participate actively in social life many years after retirement and upbringing of children. In Germany, over 80 % of the population 60 years and older are living independently in the community, and approximately 95 % stay in their own homes. On the other hand, the probability to suffer from diseases, frailty and impaired activities of daily life activities also rises with higher age. However, only on rare occasions older people in need of nursing care do like to give up their home voluntarily. Next to innovative forms of dwelling, home replacement, technical aids and us of information and communication technology (ICT), efforts to strengthen the older persons' independence of maintaining mobility in their home environment (life space) is emphasised in this article. The particular focus is on the use of preventative strategies and to support geriatric network facilities. PMID:26445251

  3. Lung cancer in women and type of dwelling in relation to radon exposure

    SciTech Connect

    Svensson, C.; Pershagen, G.; Klominek, J.

    1989-04-01

    A case-control study based on interviews with 210 incident female lung cancer patients, 209 age-matched population controls, and 191 hospital controls was carried out in Stockholm county, Sweden. Radon measurements made in a sample of 303 dwellings, in which the study subjects had lived, showed that dwellings with ground contact had an average concentration of approximately 160 Bqm-3, twice the average concentration of other dwellings. A cumulated radon exposure index was calculated for each subject based on data from the interviews and the measurements. For the total group of lung cancer a relative risk (RR), adjusted for smoking, age, and degree of urbanization, of 1.8 (95% confidence interval: 1.2-2.9) and 1.7 (0.9-3.3) associated with ''intermediate'' and ''high'' exposure to radon was found. There was also a significant trend to a positive dose-response relationship (Ptrend = 0.03). For small cell cancer the corresponding figures for RRs were 1.9 (0.6-4.5) and 4.7 (1.5-14.2), respectively (Ptrend = 0.01). There seemed to be a positive interaction between radon exposure and smoking in relation to lung cancer. The findings indicate that domestic radon may be of importance for the induction of lung cancer, particularly for some histological types.

  4. Balancing out dwelling and moving: optimal sensorimotor synchronization.

    PubMed

    Cos, Ignasi; Girard, Benoît; Guigon, Emmanuel

    2015-07-01

    Sensorimotor synchronization is a fundamental skill involved in the performance of many artistic activities (e.g., music, dance). After a century of research, the manner in which the nervous system produces synchronized movements remains poorly understood. Typical rhythmic movements involve a motion and a motionless phase (dwell). The dwell phase represents a sizable fraction of the rhythm period, and scales with it. The rationale for this organization remains unexplained and is the object of this study. Twelve participants, four drummers (D) and eight nondrummers (ND), performed tapping movements paced at 0.5-2.5 Hz by a metronome. The participants organized their tapping behavior into dwell and movement phases according to two strategies: 1) Eight participants (1 D, 7 ND) maintained an almost constant ratio of movement time (MT) and dwell time (DT) irrespective of the metronome period. 2) Four participants increased the proportion of DT as the period increased. The temporal variabilities of both the dwell and movement phases were consistent with Weber's law, i.e., their variability increased with their durations, and the longest phase always exhibited the smallest variability. We developed an optimal statistical model that formalized the distribution of time into dwell and movement intervals as a function of their temporal variability. The model accurately predicted the participants' dwell and movement durations irrespective of their strategy and musical skill, strongly suggesting that the distribution of DT and MT results from an optimization process, dependent on each participant's skill to predict time during rest and movement. PMID:25878154

  5. Wind turbine sound pressure level calculations at dwellings.

    PubMed

    Keith, Stephen E; Feder, Katya; Voicescu, Sonia A; Soukhovtsev, Victor; Denning, Allison; Tsang, Jason; Broner, Norm; Leroux, Tony; Richarz, Werner; van den Berg, Frits

    2016-03-01

    This paper provides calculations of outdoor sound pressure levels (SPLs) at dwellings for 10 wind turbine models, to support Health Canada's Community Noise and Health Study. Manufacturer supplied and measured wind turbine sound power levels were used to calculate outdoor SPL at 1238 dwellings using ISO [(1996). ISO 9613-2-Acoustics] and a Swedish noise propagation method. Both methods yielded statistically equivalent results. The A- and C-weighted results were highly correlated over the 1238 dwellings (Pearson's linear correlation coefficient r > 0.8). Calculated wind turbine SPLs were compared to ambient SPLs from other sources, estimated using guidance documents from the United States and Alberta, Canada. PMID:27036282

  6. WEST ELEVATION. DWELLING AND FLAG TOWER ARE IN THE DISTANCE. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    WEST ELEVATION. DWELLING AND FLAG TOWER ARE IN THE DISTANCE. HAZARDOUS MATERIAL STORAGE SHED IS IN THE FOREGROUND. - U.S. Coast Guard Lake Worth Inlet Station, Boathouse, Peanut Island, Riviera Beach, Palm Beach County, FL

  7. SOUTH ELEVATION. THE DWELLING, FLAG TOWER, AND HAZARDOUS MATERIAL STORAGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    SOUTH ELEVATION. THE DWELLING, FLAG TOWER, AND HAZARDOUS MATERIAL STORAGE SHED ARE VISIBLE IN THE BACKGROUND. - U.S. Coast Guard Lake Worth Inlet Station, Boathouse, Peanut Island, Riviera Beach, Palm Beach County, FL

  8. 249. Photocopied July 1978. (QMC) DRAWING OF SINGLEFAMILY DWELLING AT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    249. Photocopied July 1978. (QMC) DRAWING OF SINGLE-FAMILY DWELLING AT 'QUINCY MINE. JULY 26TH, 1899.' BASEMENT, FIRST AND SECOND FLOOR PLANS AND ELEVATION. - Quincy Mining Company, Hancock, Houghton County, MI

  9. Low cycle dwell-time fatigue in Ti-6242

    SciTech Connect

    Kassner, M.E.; Kosaka, Y.; Hall, J.A.

    1999-09-01

    Ambient-temperature, low-cycle dwell-time and conventional low-cycle fatigue tests were performed on Ti-6Al-2Sn-4Zr-2Mo-0.1Si (Ti-6242). Specimens were solution annealed at various temperatures below the beta transus to control the volume fraction of primary alpha phase and were subsequently shot-peened. The influence of the changes in primary alpha phase on the low-cycle dwell-time fatigue life (LCDF) were determined and compared to the conventional low-cycle fatigue (LCF) properties of the alloy. A 120-second dwell significantly decreased the number of cycles to failure, although the factor decrease of LCF from a dwell, in general, diminished with decreasing stress. The Increasing primary alpha phase associated with lower solution temperatures appears to increase susceptibility to low-cycle dwell-time fatigue. It also appears that the susceptibility to dwell fatigue may be associated with ambient-temperature, time-dependent, cyclic (creep) plasticity.

  10. Semi-volatile organic compounds in the particulate phase in dwellings: A nationwide survey in France

    NASA Astrophysics Data System (ADS)

    Mandin, Corinne; Mercier, Fabien; Ramalho, Olivier; Lucas, Jean-Paul; Gilles, Erwann; Blanchard, Olivier; Bonvallot, Nathalie; Glorennec, Philippe; Le Bot, Barbara

    2016-07-01

    Sixty-six semi-volatile organic compounds (SVOCs)-phthalates, polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), one pyrethroid, organochlorine and organophosphorous pesticides, alkylphenols, synthetic musks, tri-n-butylphosphate and triclosan-were measured on PM10 filters collected over 7 days during a nationwide survey of 285 French dwellings, representative of nearly 25 million housing units. Thirty-five compounds were detected in more than half of the dwellings. PAHs, phthalates and triclosan were the major particle-bound SVOCs, with a median concentration greater than 1 ng m-3 for butylbenzyl phthalate (BBP) (median: 1.6 ng m-3), di(2-ethylhexyl) phthalate (DEHP) (46 ng m-3) and di-iso-nonyl phthalate (DiNP) (7.9 ng m-3), and greater than 0.1 ng m-3 for triclosan (114 pg m-3), benzo(a)pyrene (138 pg m-3), benzo(b)fluoranthene (306 pg m-3), benzo(g,h,i)perylene (229 pg m-3), and indeno(1,2,3-c,d)pyrene (178 pg m-3). For most of the SVOCs, higher concentrations were found in the dwellings of smokers and during the heating season. The concentrations of banned SVOCs-namely, PCBs and organochlorine pesticides-were correlated. Permethrin, 4-tert-butylphenol and bisphenol-A showed no correlation with the other SVOCs and seemed to have their own specific sources. Most SVOCs were positively associated with PM10 concentration, suggesting that any factor that raises the mass of indoor airborne particles also increases the exposure to SVOCs through inhalation.

  11. Enrichment of Radon and Carbon Dioxide in the Open Atmosphere of an Australian Coal Seam Gas Field

    PubMed Central

    2013-01-01

    Atmospheric radon (222Rn) and carbon dioxide (CO2) concentrations were used to gain insight into fugitive emissions in an Australian coal seam gas (CSG) field (Surat Basin, Tara region, Queensland). 222Rn and CO2 concentrations were observed for 24 h within and outside the gas field. Both 222Rn and CO2 concentrations followed a diurnal cycle with night time concentrations higher than day time concentrations. Average CO2 concentrations over the 24-h period ranged from ∼390 ppm at the control site to ∼467 ppm near the center of the gas field. A ∼3 fold increase in maximum 222Rn concentration was observed inside the gas field compared to outside of it. There was a significant relationship between maximum and average 222Rn concentrations and the number of gas wells within a 3 km radius of the sampling sites (n = 5 stations; p < 0.05). A positive trend was observed between CO2 concentrations and the number of CSG wells, but the relationship was not statistically significant. We hypothesize that the radon relationship was a response to enhanced emissions within the gas field related to both point (well heads, pipelines, etc.) and diffuse soil sources. Radon may be useful in monitoring enhanced soil gas fluxes to the atmosphere due to changes in the geological structure associated with wells and hydraulic fracturing in CSG fields. PMID:23444905

  12. Radon-222 in groundwater of the Long Valley caldera, California

    NASA Astrophysics Data System (ADS)

    Wollenberg, H. A.; Smith, A. R.; Mosier, D. F.; Flexser, S.; Clark, M.

    1984-03-01

    In the Long Valley caldera, where seismicity has continued essentially uninterrupted since mid-1980 and uplift is documented, samples of water from hot, warm, and cold springs have been collected since September, 1982, and their222Rn concentrations analyzed. Concurrently, rocks encompassing the hydrologic systems feeding the springs were analyzed for their radioelement contents, because their uranium is the ultimate source of the222Rn in the water. The222Rn concentration in the springs varies inversely with their temperature and specific conductance. High concentrations (1500 to 2500 picocuries per liter) occur in dilute cold springs on the margins of the caldera, while low contents (12 to 25 pCi/l) occur in hot to boiling springs. Springwater radon concentrations also correlate slightly with the uranium content of the encompassing rocks. A continuous monitoring system was installed in August, 1983, at a spring issuing from basalt, to provide hourly records of radon concentration. A gamma detector is submerged in a natural pool, and we have observed that the radioactivity measured in this manner is due almost entirely to the222Rn concentration of the water. Initial operation shows diurnal and semidiurnal variations in the222Rn concentration of the springwater that are ascribed to earth tides, suggesting that those variations are responding to small changes in stress in the rocks encompassing the hydrologic system.

  13. Development of a marsh-based upwelling injection system to treat domestic wastewater from coastal dwellings

    SciTech Connect

    Rusch, K.A.; Jones, S.C.

    1999-07-01

    The objective of this study was the design, construction and evaluation of a natural, marsh-based system using a sand/soil bed in a shallow upwelling field to remove fecal coliforms from coastal dwelling wastewater. Wastewater was injected at a 15 foot depth and movement of the wastewater was monitored with wells at 5, 10, and 15 foot depths. Monitoring salinity showed development of an extensive fresh water plume at the 5 foot depth, less at the 10 foot and none at the 15 foot depth; the system effectively reduced the fecal coliform concentrations to <1 colony per 100 mL as the wastewater traveled through the soil.

  14. Measuring radon concentrations and estimating dose in tourist caves.

    PubMed

    Martín Sánchez, A; de la Torre Pérez, J; Ruano Sánchez, A B; Naranjo Correa, F L

    2015-11-01

    Caves and mines are considered to be places of especial risk of exposure to (222)Rn. This is particularly important for guides and workers, but also for visitors. In the Extremadura region (Spain), there are two cave systems in which there are workers carrying out their normal everyday tasks. In one, visits have been reduced to maintain the conditions of temperature and humidity. The other comprises several caves frequently visited by school groups. The caves were radiologically characterised in order to estimate the dose received by workers or possible hazards for visitors. PMID:25948834

  15. Robust stability of positive switched systems with dwell time

    NASA Astrophysics Data System (ADS)

    Liu, Jinjin; Zhang, Kanjian; Wei, Haikun

    2016-08-01

    This paper studies robust stability of positive switched systems (PSSs) with polytopic uncertainties in both discrete-time and continuous-time contexts. By using multiple linear copositive Lyapunov functions, a sufficient condition for stability of PSSs with dwell time is addressed. Being different from time-invariant multiple linear copositive Lyapunov functions, the Lyapunov functions constructed in this paper are time-varying during the dwell time and time-invariant afterwards. Then, robust stability of PSSs with polytopic uncertainties is solved. All conditions are solvable via linear programming. Finally, illustrative examples are given to demonstrate the validity of the proposed results.

  16. Transpiration from forest dwelling and woodland Mygalomorphae (Araneae)

    NASA Astrophysics Data System (ADS)

    Cloudsley-Thompson, J. L.; Constantinou, C.

    1983-03-01

    Rates of water loss in dry air at room temperature (21±2°C) have been measured from seven species of forest-dwelling mygalomorph spiders. They range from 0.260% body wt h-1 in the tube-dwelling trapdoor spider Dyarcyops sp. (from the humid coastal regions of eastern Australia) to 0.030% wt h-1 in Brachypelma smithi (from drier environments in Mexico). There is a tendency for rates of transpiration to be related to the humidities of the spiders' normal environments and micro-habitats.

  17. Volatile and semi-volatile organic compounds of respiratory health relevance in French dwellings.

    PubMed

    Dallongeville, A; Costet, N; Zmirou-Navier, D; Le Bot, B; Chevrier, C; Deguen, S; Annesi-Maesano, I; Blanchard, O

    2016-06-01

    Over the last decades, the prevalence of childhood respiratory conditions has dramatically increased worldwide. Considering the time spent in enclosed spaces, indoor air pollutants are of major interest to explain part of this increase. This study aimed to measure the concentrations of pollutants known or suspected to affect respiratory health that are present in dwellings in order to assess children's exposure. Measurements were taken in 150 homes with at least one child, in Brittany (western France), to assess the concentrations of 18 volatile organic compounds (among which four aldehydes and four trihalomethanes) and nine semi-volatile organic compounds (seven phthalates and two synthetic musks). In addition to descriptive statistics, a principal component analysis (PCA) was used to investigate grouping of contaminants. Formaldehyde was highly present and above 30 μg/m(3) in 40% of the homes. Diethyl phthalate, diisobutyl phthalate, and dimethylphthalate were quantified in all dwellings, as well as Galaxolide and Tonalide. For each chemical family, the groups appearing in the PCA could be interpreted in term of sources. The high prevalence and the levels of these compounds, with known or suspected respiratory toxicity, should question regulatory agencies to trigger prevention and mitigation actions. PMID:26010323

  18. 10 CFR 440.22 - Eligible dwelling units.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Office of Management and Budget. (b) A subgrantee may weatherize a building containing rental dwelling... posted by DOE of Assisted Housing and Public Housing buildings identified by the U.S. Department of Housing and Urban Development as meeting those requirements. (ii) A building containing rental...

  19. 10 CFR 440.22 - Eligible dwelling units.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Office of Management and Budget. (b) A subgrantee may weatherize a building containing rental dwelling... posted by DOE of Assisted Housing and Public Housing buildings identified by the U.S. Department of Housing and Urban Development as meeting those requirements. (ii) A building containing rental...

  20. Dwell Time Symmetry in Random Walks and Molecular Motors

    PubMed Central

    Lindén, Martin; Wallin, Mats

    2007-01-01

    The statistics of steps and dwell times in reversible molecular motors differ from those of cycle completion in enzyme kinetics. The reason is that a step is only one of several transitions in the mechanochemical cycle. As a result, theoretical results for cycle completion in enzyme kinetics do not apply to stepping data. To allow correct parameter estimation, and to guide data analysis and experiment design, a theoretical treatment is needed that takes this observation into account. In this article, we model the distribution of dwell times and number of forward and backward steps using first passage processes, based on the assumption that forward and backward steps correspond to different directions of the same transition. We extend recent results for systems with a single cycle and consider the full dwell time distributions as well as models with multiple pathways, detectable substeps, and detachments. Our main results are a symmetry relation for the dwell time distributions in reversible motors, and a relation between certain relative step frequencies and the free energy per cycle. We demonstrate our results by analyzing recent stepping data for a bacterial flagellar motor, and discuss the implications for the efficiency and reversibility of the force-generating subunits. PMID:17369422

  1. 24 CFR 990.140 - Occupied dwelling units.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Eligible Unit Months § 990.140 Occupied dwelling units. A PHA is eligible to receive operating subsidy for public housing units for each unit month that those units are under an ACC and occupied by a public housing-eligible family under lease....

  2. Variance of the Quantum Dwell Time for a Nonrelativistic Particle

    NASA Technical Reports Server (NTRS)

    Hahne, Gerhard

    2012-01-01

    Munoz, Seidel, and Muga [Phys. Rev. A 79, 012108 (2009)], following an earlier proposal by Pollak and Miller [Phys. Rev. Lett. 53, 115 (1984)] in the context of a theory of a collinear chemical reaction, showed that suitable moments of a two-flux correlation function could be manipulated to yield expressions for the mean quantum dwell time and mean square quantum dwell time for a structureless particle scattering from a time-independent potential energy field between two parallel lines in a two-dimensional spacetime. The present work proposes a generalization to a charged, nonrelativistic particle scattering from a transient, spatially confined electromagnetic vector potential in four-dimensional spacetime. The geometry of the spacetime domain is that of the slab between a pair of parallel planes, in particular those defined by constant values of the third (z) spatial coordinate. The mean Nth power, N = 1, 2, 3, . . ., of the quantum dwell time in the slab is given by an expression involving an N-flux-correlation function. All these means are shown to be nonnegative. The N = 1 formula reduces to an S-matrix result published previously [G. E. Hahne, J. Phys. A 36, 7149 (2003)]; an explicit formula for N = 2, and of the variance of the dwell time in terms of the S-matrix, is worked out. A formula representing an incommensurability principle between variances of the output-minus-input flux of a pair of dynamical variables (such as the particle s time flux and others) is derived.

  3. Resilience in Rural Community-Dwelling Older Adults

    ERIC Educational Resources Information Center

    Wells, Margaret

    2009-01-01

    Context: Identifying ways to meet the health care needs of older adults is important because their numbers are increasing and they often have more health care issues. High resilience level may be one factor that helps older adults adjust to the hardships associated with aging. Rural community-dwelling older adults often face unique challenges such…

  4. Proactive Coping in Community-Dwelling Older Australians

    ERIC Educational Resources Information Center

    Sougleris, Christina; Ranzijn, Rob

    2011-01-01

    This article reports on a study of older community-dwelling Australian adults which aimed to test whether a relatively unexplored construct, proactive coping, could have a role in purpose in life, personal growth, and life satisfaction. A total of 109 women and 115 men (Mean age = 75.04 yrs, SD = 6.66) completed a questionnaire containing…

  5. Gender and Transportation Access among Community-Dwelling Seniors

    ERIC Educational Resources Information Center

    Dupuis, Josette; Weiss, Deborah R.; Wolfson, Christina

    2007-01-01

    Purpose: This study estimates the prevalence of problems with transportation in a sample of community-dwelling seniors residing in an urban setting and investigates the role that gender plays in the ability of seniors to remain mobile in their communities. Design and Methods: Data collected as part of a study assessing the prevalence and…

  6. 24 CFR 200.926 - Minimum property standards for one and two family dwellings.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... and two family dwellings. 200.926 Section 200.926 Housing and Urban Development Regulations Relating... Minimum Property Standards § 200.926 Minimum property standards for one and two family dwellings. (a... acceptable code; and (2) Those portions of the CABO One and Two Family Dwelling Code designated by the...

  7. Radon and thoron levels, their spatial and seasonal variations in adobe dwellings - a case study at the great Hungarian plain.

    PubMed

    Szabó, Zsuzsanna; Jordan, Gyozo; Szabó, Csaba; Horváth, Ákos; Holm, Óskar; Kocsy, Gábor; Csige, István; Szabó, Péter; Homoki, Zsolt

    2014-06-01

    Radon and thoron isotopes are responsible for approximately half of the average annual effective dose to humans. Although the half-life of thoron is short, it can potentially enter indoor air from adobe walls. Adobe was a traditional construction material in the Great Hungarian Plain. Its major raw materials are the alluvial sediments of the area. Here, seasonal radon and thoron activity concentrations were measured in 53 adobe dwellings in 7 settlements by pairs of etched track detectors. The results show that the annual average radon and thoron activity concentrations are elevated in these dwellings and that the proportions with values higher than 300 Bq m(-3) are 14-17 and 29-32% for radon and thoron, respectively. The calculated radon inhalation dose is significantly higher than the world average value, exceeding 10 mSv y(-1) in 7% of the dwellings of this study. Thoron also can be a significant contributor to the inhalation dose with about 30% in the total inhalation dose. The changes of weather conditions seem to be more relevant in the variation of measurement results than the differences in the local sedimentary geology. Still, the highest values were detected on clay. Through the year, radon follows the average temperature changes and is affected by the ventilation, whereas thoron rather seems to follow the amount of precipitation. PMID:24437932

  8. Determinants of Living Situation in a Population of Community-Dwelling and Assisted-Living Dwelling Elders

    PubMed Central

    Avery, Erika; Kleppinger, Alison; Feinn, Richard; Kenny, Anne M

    2010-01-01

    Objective To determine what variables separate community-dwelling elders from assisted-living dwelling elders. Design Cross-sectional Setting Community and assisted living facilities in Connecticut Participants 114 individuals (77 community-dwelling, 37 assisted living) Assessments Nutritional survey, 6 minute walk, Mini-Mental Status Exam (MMSE), Center of Epidemiologic Studies (CES)-Depression Scale, 25-OH vitamin D Results At baseline, assisted-living dwelling elders appeared to have lower serum 25-OH vitamin D levels, lower MMSE scores, higher CES-depression scale scores, and walked shorter distances in the six minute walk. Serum 25-OH vitamin D levels and six minute walk were significantly different between the two groups using logistic regression analysis. As serum 25-OH vitamin D levels increased, the probability of an elder living in an ALF decreased, and as distance walked during the six minute walk increased, the probability of an elder living in an ALF decreased. Conclusions Elders living in assisted living facilities had significantly lower 25-OH vitamin D levels and walked shorter distances during the six minute walk. These variables can be used to predict the probability of an elder living in an assisted living facility. The lack of effect of nutrition suggests that the role of vitamin D in this setting is in physical function. PMID:20142070

  9. Transmission factors for the penetration of neutron and photon fluence into wood-frame dwellings, 1990 (TF90)

    SciTech Connect

    Rhoades, W.A.; Lillie, R.A.; Emmett, M.B.

    1992-05-01

    An earlier study at Oak Ridge calculated radiation doses to persons inside reinforced concrete buildings during the exposure at Nagasaki. The DS86'' study conducted at several laboratories in the United States and Japan concentrated on persons inside wood-frame dwellings at both Nagasaki and Hiroshima. The present study is directed toward applying the general technical approach of the DS86. Numerous simplifications were indicated as a result of the earlier research, and the numerical results are represented as transmission factors'' relating radiation outside the dwellings to doses received by individuals within. An advantage of this method is that the transmission factors can be presented in tables that can be reviewed, inspected, and applied in a very tangible and straightforward manner.

  10. Transmission factors for the penetration of neutron and photon fluence into wood-frame dwellings, 1990 (TF90)

    SciTech Connect

    Rhoades, W.A.; Lillie, R.A.; Emmett, M.B.

    1992-05-01

    An earlier study at Oak Ridge calculated radiation doses to persons inside reinforced concrete buildings during the exposure at Nagasaki. The ``DS86`` study conducted at several laboratories in the United States and Japan concentrated on persons inside wood-frame dwellings at both Nagasaki and Hiroshima. The present study is directed toward applying the general technical approach of the DS86. Numerous simplifications were indicated as a result of the earlier research, and the numerical results are represented as ``transmission factors`` relating radiation outside the dwellings to doses received by individuals within. An advantage of this method is that the transmission factors can be presented in tables that can be reviewed, inspected, and applied in a very tangible and straightforward manner.

  11. Evaluation of groundwater discharge into small lakes based on the temporal distribution of radon-222

    USGS Publications Warehouse

    Dimova, N.T.; Burnett, W.C.

    2011-01-01

    In order to evaluate groundwater discharge into small lakes we constructed a model that is based on the budget of 222Rn (radon t1/2 5 3.8 d) as a tracer. The main assumptions in our model are that the lake's waters are wellmixed horizontally and vertically; the only significant 222Rn source is via groundwater discharge; and the only losses are due to decay and atmospheric evasion. In order to evaluate the groundwater-derived 222Rn flux, we monitored the 222Rn concentration in lake water over periods long enough (usually 1-3 d) to observe changes likely caused by variations in atmospheric exchange (primarily a function of wind speed and temperature). We then attempt to reproduce the observed record by accounting for decay and atmospheric losses and by estimating the total 222Rn input flux using an iterative approach. Our methodology was tested in two lakes in central Florida: one of which is thought to have significant groundwater inputs (Lake Haines) and another that is known not to have any groundwater inflows but requires daily groundwater augmentation from a deep aquifer (Round Lake). Model results were consistent with independent seepage meter data at both Lake Haines (positive seepage of ??? 1.6 ?? 104 m3 d-1 in Mar 2008) and at Round Lake (no net groundwater seepage). ?? 2011, by the American Society of Limnology and Oceanography, Inc.

  12. Long-term temporal variability of the radon-222 exhalation flux from a landform covered by low uranium grade waste rock.

    PubMed

    Bollhöfer, Andreas; Doering, Che

    2016-01-01

    Radon-222 exhalation flux densities from two different substrates of several metres thickness, waste rock and waste rock mixed with approximately 30% lateritic material, were measured over a period of five years in the wet-dry tropics of Northern Australia. Fourteen measurement campaigns using activated charcoal canisters (n > 1000) covered both dry and wet seasons and showed differences in seasonal and long term trends of the (222)Rn exhalation flux densities normalised to the (226)Ra activity concentrations of the substrate. Dry season (222)Rn exhalation was generally higher for the mixed substrate, due to the larger fraction of fines. Seasonality established within the first year of landform construction on the mixed substrate, due to the higher water holding capacity of the lateritic material. In contrast, waste rock only shows no seasonality until years four and five after construction, when average normalised dry season (222)Rn exhalation flux densities from waste rock increase to values (0.47 ± 0.06 mBq m(-2) s(-1) per Bq kg(-1)) similar to the mixed substrate (0.64 ± 0.08 mBq m(-2) s(-1) per Bq kg(-1)), likely due to an increase in fines from rapid weathering of the schistose waste rock. Volumetric water content has been used to parametrize relative (222)Rn exhalation and we determined that wet season (222)Rn exhalation is about 40% of the dry season exhalation. PMID:26100675

  13. The effects of high ambient radon on thermoluminescence dosimetry readings.

    PubMed

    Harvey, John A; Kearfott, Kimberlee J

    2011-11-01

    The effect of a high level of ambient (222)Rn gas on thermoluminescence dosemeters (TLDs) is examined. Groups of LiF:Mg,Ti and CaF(2):Dy TLDs were exposed to (222)Rn under controlled environmental conditions over ∼7 d using a luminous (226)Ra aircraft dial. LiF:Mg,Ti TLDs were tested bare, and both types were tested mounted in cards used for environmental dosimetry and mounted in cards enclosed in plastic badges. A passive continuous radon monitor was used to measure the (222)Rn level in the small chamber during the experiments. The data were analysed to determine the relationship between the integrated (222)Rn level and the TLD response. Although both LiF:Mg,Ti and CaF(2):Dy TLDs showed a strong response to (222)Rn, the badges prevented measurable radon detection by the TLDs within. The TLDs were not used to directly measure the radon concentration; rather, a correction for its influence was desired. PMID:21177272

  14. Calibration of diffusion barrier charcoal detectors and application to radon sampling in dwellings

    NASA Astrophysics Data System (ADS)

    Cabrera, M. E. M.; Sujo, L. C.; Villalba, L.; Peinado, J. S.; Jimenez, A. C.; Baca, A. M.; Gandara, S. D.; Villalobos, M. R.; Miranda, A. L.; Peraza, E. F. H.

    2003-10-01

    Some calibration conditions of diffusion barrier charcoal canister (DBCC) detectors for measuring radon concentration in air were studied. A series of functional expressions and graphs were developed to describe relationship between radon concentration in air and the activity adsorbed in DBCC, when placed in small chambers. A semi-empirical expression for the DBCC calibration was obtained, based on the detector integration time and the adsorption coefficient of radon on activated charcoal. Both, the integration time for 10% of DBCC of the same batch, and the adsorption coefficient of radon for the activated charcoal used in these detectors, were experimentally determined. Using these values as the calibration parameters, a semi-empirical calibration function was used for the interpretation of the radon activities in the detectors used for sampling more than 200 dwellings in the major cities of the state of Chihuahua, Mexico.

  15. Indirect measurement sub floor radon using passive detectors

    SciTech Connect

    Chittaporn, P.; Harley, N.H.

    1996-06-01

    Hourly {sup 222}Rn measurements have been made in an 80-y-old wood frame house for about 6 y. The average {sup 222}Rn concentration in the basement is 40 Bq m{sup -3}. Two holes were drilled in the slab and standard 150 cfm fans installed via a short length of PVC pipe. The air from beneath the slab was blown directly into the basement to indirectly study the long term variability in the subslab gas concentration. Passive CR-39 {sup 222}Rn alpha track detectors of our design were placed weekly in the fan exit air to estimate the average subslab gas concentration. Instantaneous subslab gas {sup 222}Rn concentration was measured directly using scintillation flasks filled from adjacent floor ports once per week. The agreement with the indirect measurements was good. The average weekly basement {sup 222}Rn concentration correlated well with the weekly integrated soil gas {sup 222}Rn concentration. An increase from 44 to 74 Bq m{sup -3} in basement air corresponded to an increase of 1.8 to 3.7 MBq m{sup -3} in subslab soil gas. An increase in weekly average temperature from 10{degrees} to 30{degrees}C increased the integrated soil gas concentration from 1.8 to 3.7 MBq m{sup -3}, and an increase in average wind speed from calm to 0.5 in s{sup -1} decreased the subslab concentration from 3.7 to 1.8 MBq m{sup -3}.

  16. Dry deposition of peroxyacetyl nitrate (PAN): Determination of its deposition velocity at night from measurements of the atmospheric PAN and 222Radon concentration gradient

    NASA Astrophysics Data System (ADS)

    Schrimpf, Wolfram; Lienaerts, Karlheinz; Müller, Klaus Peter; Rudolph, Jochen; Neubert, Rolf; Schüßler, Wolfram; Levin, Ingeborg

    During the field campaign POPCORN (Photooxidant Formation by Plant Emitted Compounds and OH-Radicals in North-Eastern Germany) in August 1994 we measured the nighttime deposition velocities of PAN above a corn field. These are the first absolute measurements of PAN deposition velocities in the field. The deposition velocities were derived using a novel method, which uses measurements of the gradients of PAN and 222Rn and of the emission rates of 222Rn from the soil. A unique data set of about 250 field measurements of the PAN deposition velocity at night was thus obtained. The deposition velocity at night proved to be highly variable with an average of 0.54 cm/s and a standard deviation of 0.94 cm/s. Recent presumptions by Shepson et al. [1992] that the PAN deposition velocity is strongly reduced with increasing relative humidity could not be confirmed by our measurements.

  17. Factors underlying residential radon concentration: Results from Galicia, Spain

    SciTech Connect

    Barros-Dios, J.M.; Gastelu-Iturri, J.; Figueiras, A.

    2007-02-15

    Radon causes lung cancer when inhaled for prolonged periods of time. A range of factors influence residential radon concentration and this study therefore sought to ascertain which dwelling-related factors exert an influence on radon levels. A cross-sectional study was conducted from 2001 to 2003 which analyzed 983 homes of as many subjects randomly selected from the 1991 census. Sampling was carried out by district and stratified by population density to ensure that more detectors were placed in the most heavily populated areas. Radon concentration and different dwelling characteristics were measured in each of the homes selected. Bivariate and multivariate analyses were performed to ascertain which factors influenced radon concentration. The geometric mean of radon concentration was 69.5 Bq/m{sup 3}, and 21.3% of homes had concentrations above 148 Bq/m{sup 3}. Factors shown to influence radon concentration in the bivariate analysis were: age of dwelling; interior building material; exterior building material; and storey on which the detector was placed. Explanatory variables in the multivariate analysis were: age of dwelling; number of storeys; distance off floor; and interior building material. The model was significant, but the variability explained was around 10%. These results highlight the fact that the study area is an area of high radon emission and that factors other than those directly related with the characteristics of the dwelling also influence radon concentration.

  18. Intercomparison study of atmospheric methane and carbon dioxide concentrations measured at the Ebre River Delta Station

    NASA Astrophysics Data System (ADS)

    Occhipinti, Paola; Morguí, Josep Anton; Àgueda, Alba; Batet, Oscar; Borràs, Sílvia; Cañas, Lídia; Curcoll, Roger; Grossi, Claudia; Nofuentes, Manel; Vazquez, Eusebi; Rodó, Xavier

    2015-04-01

    In the framework of the ClimaDat project, IC3 has established a network of eight monitoring stations across the Iberian Peninsula and the Canarian Archipelago with the aim of studying climate processes. The monitoring station at the Ebre River Delta (DEC3) is located in the Ebre River Delta Natural Park (40° 44' N; 0° 47' E) and it is characterized by the typical North-Western Mediterranean climate. Since 2013, atmospheric greenhouse gases (GHG) and 222Rn tracer gas together with the meteorological parameters are continuously measured from a 10 m a.g.l. height tower. Atmospheric GHG (CO2, CH4, CO and N2O) concentrations are determined using a Picarro analyzer G2301 (CO2 and CH4) and a modified gas chromatograph (GC) Agilent 6890N (CO2, CH4, CO and N2O). Open data access is available from the www.climadat.es website. Data collected at the DEC3 station are also submitted to the InGOS platform since this station is part of the InGOS European infrastructure project. Researchers from the Laboratory of the Atmosphere and the Oceans (LAO) at IC3 have performed an intercomparison study at the DEC3 site between three different Picarro analyzers (two Picarro G2301 and one Picarro G2301M), a Los Gatos Research (LGR) analyzer and the GC system already installed at the station. The aim of this study is to compare and assess the measuring agreement between the four optical gas analyzers and the GC. In the first part of the experiment, all instruments have been calibrated using NOAA gases as primary standards analyzing five Praxair provided targets to evaluate the precision of the measuring instruments. Max Plank Institute (MPI) gases have been used as secondary standards for the GC whereas Praxair provided tanks are used as secondary standards for the Picarro and the LGR analyzers. In the second part of the experiment, atmospheric GHG were measured from natural atmospheric air taken from a 10 m a.g.l. inlet. Daily cycles of GHG measurements were carried out using different

  19. Additional contamination when radon is in excess.

    PubMed

    Martín Sánchez, A; de la Torre Pérez, J; Ruano Sánchez, A B; Naranjo Correa, F L

    2013-11-01

    A study of the behavior of the (222)Rn progeny on clothes, skin and hair has been performed in a place with very high radon concentration. In the past, radon concentration was established to be about 32 kBq/m(3) in a very high humidity environment inside a tourist cave in Extremadura (Spain). The results show that (222)Rn daughters are adhered on clothes, skin and hair, adding some radioactive concentration to that due to radon and its progeny existing in the breathable air. PMID:23548693

  20. Radon emissions related to the granitic Precambrian shield in southern Brazil.

    PubMed

    Fianco, Ana C B; Roisenberg, Ari; Bonotto, Daniel M

    2013-01-01

    The equivalent uranium (eU) activity concentration was analysed in selected granite samples at several sites in Porto Alegre, Southern Brazil, to obtain information on the radon ((222)Rn) generation by the aquifer rock matrices. Radon analyses of ground water and soil samples were also performed. Several samples exhibited a dissolved (222)Rn activity concentration exceeding the World Health Organization maximum limit of 100 Bq l(-1). The dissolved radon content in ground waters from the Fractured Precambrian Aquifer System exhibited a direct significant correlation with the eU in the rock matrices, which is a typical result of water-rock interactions. Variation in the soil's porosity was confirmed as an important factor for (222)Rn release, as expected, due to its gaseous nature. Thus, although the calcic-alkaline to alkaline Precambrian granitoid rocks of the study area are important reservoirs for underground resources, they can release high amounts of radon gas into the liquid phase. PMID:22852747

  1. Are Industrial Towns Safe for Human Dwelling?

    NASA Astrophysics Data System (ADS)

    Singla, C.; Garg, S.; Aggarwal, R.; Jutla, A. S.

    2012-12-01

    Water resources in the developing countries are under severe stress with multiple stakeholders claiming rights to it. Regional industries, in absence to strict regulations, are responsible for dumping toxic wastes to rivers, ponds and other waterway which have devastating effects on water habitat as well as population that derives water for its daily needs. Key methodological challenges remain in connecting environment to levels of pollution and its relationship with diseases that affect humans. We present a case study from one of the highly industrialized town of South Asia. Ludhiana is the largest city and the largest urban settlement in Punjab, India. With the development of industry, agriculture and the growth of urban population, its water pollution has become a serious problem. Here, we will show how the distribution of heavy metals for groundwater affects its quality and role of regional hydrology on it. We will start with one of the major waterways in the Ludhiana district. Groundwater water samples including sewage water sample were collected within its vicinity of 2.0 km along the waterway (Buddha Nala). The concentration of nickel(Ni) and iron(Fe) in sewage water as well as in groundwater samples was much higher than the maximum permissible limits at a distance of 1.0 Km away from Buddha Nala. In general, all the groundwater samples collected beyond 1.0 Km away from Buddha Nala were found to be having normal concentrations of arsenic and Fe. We will also demonstrate regional health problems resulting from poor groundwater quality. Role of regional hydrology in modulating water quality will be discussed.

  2. Variance of the quantum dwell time for a nonrelativistic particle

    SciTech Connect

    Hahne, G. E.

    2013-01-15

    Munoz, Seidel, and Muga [Phys. Rev. A 79, 012108 (2009)], following an earlier proposal by Pollak and Miller [Phys. Rev. Lett. 53, 115 (1984)] in the context of a theory of a collinear chemical reaction, showed that suitable moments of a two-flux correlation function could be manipulated to yield expressions for the mean quantum dwell time and mean square quantum dwell time for a structureless particle scattering from a time-independent potential energy field between two parallel lines in a two-dimensional spacetime. The present work proposes a generalization to a charged, nonrelativistic particle scattering from a transient, spatially confined electromagnetic vector potential in four-dimensional spacetime. The geometry of the spacetime domain is that of the slab between a pair of parallel planes, in particular, those defined by constant values of the third (z) spatial coordinate. The mean Nth power, N= 1, 2, 3, Horizontal-Ellipsis , of the quantum dwell time in the slab is given by an expression involving an N-flux-correlation function. All these means are shown to be nonnegative. The N= 1 formula reduces to an S-matrix result published previously [G. E. Hahne, J. Phys. A 36, 7149 (2003)]; an explicit formula for N= 2, and of the variance of the dwell time in terms of the S-matrix, is worked out. A formula representing an incommensurability principle between variances of the output-minus-input flux of a pair of dynamical variables (such as the particle's time flux and others) is derived.

  3. Variance of the quantum dwell time for a nonrelativistic particle

    NASA Astrophysics Data System (ADS)

    Hahne, G. E.

    2013-01-01

    Muñoz, Seidel, and Muga [Phys. Rev. A 79, 012108 (2009), 10.1103/PhysRevA.79.012108], following an earlier proposal by Pollak and Miller [Phys. Rev. Lett. 53, 115 (1984), 10.1103/PhysRevLett.53.115] in the context of a theory of a collinear chemical reaction, showed that suitable moments of a two-flux correlation function could be manipulated to yield expressions for the mean quantum dwell time and mean square quantum dwell time for a structureless particle scattering from a time-independent potential energy field between two parallel lines in a two-dimensional spacetime. The present work proposes a generalization to a charged, nonrelativistic particle scattering from a transient, spatially confined electromagnetic vector potential in four-dimensional spacetime. The geometry of the spacetime domain is that of the slab between a pair of parallel planes, in particular, those defined by constant values of the third (z) spatial coordinate. The mean Nth power, N = 1, 2, 3, …, of the quantum dwell time in the slab is given by an expression involving an N-flux-correlation function. All these means are shown to be nonnegative. The N = 1 formula reduces to an S-matrix result published previously [G. E. Hahne, J. Phys. A 36, 7149 (2003), 10.1088/0305-4470/36/25/316]; an explicit formula for N = 2, and of the variance of the dwell time in terms of the S-matrix, is worked out. A formula representing an incommensurability principle between variances of the output-minus-input flux of a pair of dynamical variables (such as the particle's time flux and others) is derived.

  4. Increased gait unsteadiness in community-dwelling elderly fallers

    NASA Technical Reports Server (NTRS)

    Hausdorff, J. M.; Edelberg, H. K.; Mitchell, S. L.; Goldberger, A. L.; Wei, J. Y.

    1997-01-01

    OBJECTIVE: To test the hypothesis that quantitative measures of gait unsteadiness are increased in community-dwelling elderly fallers. STUDY DESIGN: Retrospective, case-control study. SETTING: General community. PARTICIPANTS: Thirty-five community-dwelling elderly subjects older than 70 years of age who were capable of ambulating independently for 6 minutes were categorized as fallers (age, 82.2 +/- 4.9 yrs [mean +/- SD]; n = 18) and nonfallers (age, 76.5 +/- 4.0 yrs; n = 17) based on history; 22 young (age, 24.6 +/- 1.9 yrs), healthy subjects also participated as a second reference group. MAIN OUTCOME MEASURES: Stride-to-stride variability (standard deviation and coefficient of variation) of stride time, stance time, swing time, and percent stance time measured during a 6-minute walk. RESULTS: All measures of gait variability were significantly greater in the elderly fallers compared with both the elderly nonfallers and the young subjects (p < .0002). In contrast, walking speed of the elderly fallers was similar to that of the nonfallers. There were little or no differences in the variability measures of the elderly nonfallers compared with the young subjects. CONCLUSIONS: Stride-to-stride temporal variations of gait are relatively unchanged in community-dwelling elderly nonfallers, but are significantly increased in elderly fallers. Quantitative measurement of gait unsteadiness may be useful in assessing fall risk in the elderly.

  5. Dwell time calculation for computer controlled large tool

    NASA Astrophysics Data System (ADS)

    Fan, Bin; Burge, James H.; Martin, Hubert; Zeng, Zhige; Li, Xiaojin; Zhou, Jiabin

    2012-09-01

    The Computer-controlled Large-tool such as the stressed-lap which firstly developed in the Steward Observatory Mirror Lab (SOML) [1]and the Computer controlled active lap which developed in the IOE (Institute of Optics and Electronics, Chinese Academy of Science), those large tools are controlled by computer to manufacturing large optics, especially for grinding with loose abrasive and polishing with slurry. Comparing the fixed orbital lap, computer-controlled largetool can bend its lap surface timely to match the local sub-aperture, so it always strike the high area preferentially, due to its large diameter , computer-controlled large-tool possess highly remove efficiency and generate less middle-frequency and high-frequency errors comparing some small tools such as computer controlled optical surface (CCOS), but on the other hand how to calculate the dwell time for those computer-controlled large-tool becomes a challenge comparing those small tools. Based on the mathematical removal equation for computer controlled active lap we have none negative least square algorithm to calculate the dwell time, after the simulation, a optimized algorithm based on none negative least square is provided, the dwell time calculated by this optimized algorithm meet the wanted removal volume with little residual errors.

  6. Quantum arrival and dwell times via idealized clocks

    SciTech Connect

    Yearsley, J. M.; Downs, D. A.; Halliwell, J. J.; Hashagen, A. K.

    2011-08-15

    A number of approaches to the problem of defining arrival- and dwell-time probabilities in quantum theory makes use of idealized models of clocks. An interesting question is the extent to which the probabilities obtained in this way are related to standard semiclassical results. In this paper, we explore this question using a reasonably general clock model, solved using path-integral methods. We find that, in the weak-coupling regime, where the energy of the clock is much less than the energy of the particle it is measuring, the probability for the clock pointer can be expressed in terms of the probability current in the case of arrival times, and the dwell-time operator in the case of dwell times, the expected semiclassical results. In the regime of strong system-clock coupling, we find that the arrival-time probability is proportional to the kinetic-energy density, consistent with an earlier model involving a complex potential. We argue that, properly normalized, this may be the generically expected result in this regime. We show that these conclusions are largely independent of the form of the clock Hamiltonian.

  7. Factors Influencing Dwell Fatigue Cracking in Notches of Powder Metallurgy Superalloys

    NASA Technical Reports Server (NTRS)

    Gabb, T. P.; Telesman, J.; Ghosn, L.; Garg, A.; Gayda, J.

    2011-01-01

    The influences of heat treatment and cyclic dwells on the notch fatigue resistance of powder metallurgy disk superalloys were investigated for low solvus high refractory (LSHR) and ME3 disk alloys. Disks were processed to produce material conditions with varied microstructures and associated mechanical properties. Notched specimens were first subjected to baseline dwell fatigue cycles having a dwell at maximum load, as well as tensile, stress relaxation, creep rupture, and dwell fatigue crack growth tests at 704 C. Several material heat treatments displayed a bimodal distribution of fatigue life with the lives varying by two orders-of-magnitude, while others had more consistent fatigue lives. This response was compared to other mechanical properties, in search of correlations. The wide scatter in baseline dwell fatigue life was observed only for material conditions resistant to stress relaxation. For selected materials and conditions, additional tests were then performed with the dwells shifted in part or in total to minimum tensile load. The tests performed with dwells at minimum load exhibited lower fatigue lives than max dwell tests, and also exhibited early crack initiation and a substantial increase in the number of initiation sites. These results could be explained in part by modeling evolution of peak stresses in the notch with continued dwell fatigue cycling. Fatigue-environment interactions were determined to limit life for the fatigue cycles with dwells.

  8. Implementation of the new international standards in Swiss legislation on radon protection in dwellings.

    PubMed

    Palacios Gruson, Martha; Barazza, Fabio; Murith, Christophe; Ryf, Salome

    2015-04-01

    The current revision of the Swiss Radiological Protection Ordinance aims to bring Swiss legislation in line with new international standards. In future, the control of radon exposure in dwellings will be based on a reference level of 300 Bq m(-3). Since this value is exceeded in >10 % of the buildings so far investigated nationwide, the new strategy requires the development of efficient measures to reduce radon-related health risks at an acceptable cost. The minimisation of radon concentrations in new buildings is therefore of great importance. This can be achieved, for example, through the enforcement of building regulations and the education of construction professionals. With regard to radon mitigation in existing buildings, synergies with the ongoing renewal of the building stock should be exploited. In addition, the dissemination of knowledge about radon and its risks needs to be focused on specific target groups, e.g. notaries, who play an important information role in real estate transactions. PMID:25342610

  9. Cave air ventilation and CO 2 outgassing by radon-222 modeling: How fast do caves breathe?

    NASA Astrophysics Data System (ADS)

    Kowalczk, Andrew J.; Froelich, Philip N.

    2010-01-01

    In general, the rate and timing of calcite precipitation is in part affected by variations in cave air CO 2 concentrations. Knowledge of cave ventilation processes is required to quantify the effect variations in CO 2 concentrations have on speleothem deposition rates and thus paleoclimate records. In this study we use radon-222 ( 222Rn) as a proxy of ventilation to estimate CO 2 outgassing from the cave to the atmosphere, which can be used to infer relative speleothem deposition rates. Hollow Ridge Cave, a wild cave preserve in Marianna, Florida, is instrumented inside and out with multiple micro-meteorological sensor stations that record continuous physical and air chemistry time-series data. Our time series datasets indicate diurnal and seasonal variations in cave air 222Rn and CO 2 concentrations, punctuated by events that provide clues to ventilation and drip water degassing mechanisms. Average cave air 222Rn and CO 2 concentrations vary seasonally between winter ( 222Rn = 50 dpm L - 1 , where 1 dpm L - 1 = 60 Bq m - 3 ; CO 2 = 360 ppmv) and summer ( 222Rn = 1400 dpm L - 1 ; CO 2 = 3900 ppmv). Large amplitude diurnal variations are observed during late summer and autumn ( 222Rn = 6 to 581 dpm L - 1 ; CO 2 = 360 to 2500 ppmv). We employ a simple first-order 222Rn mass balance model to estimate cave air exchange rates with the outside atmosphere. Ventilation occurs via density driven flow and by winds across the entrances which create a 'venturi' effect. The most rapid ventilation occurs 25 m inside the cave near the entrance: 45 h - 1 (1.33 min turnover time). Farther inside (175 m) exchange is slower and maximum ventilation rates are 3 h - 1 (22 min turnover time). We estimate net CO 2 flux from the epikarst to the cave atmosphere using a CO 2 mass balance model tuned with the 222Rn model. Net CO 2 flux from the epikarst is highest in summer (72 mmol m - 2 day - 1 ) and lowest in late autumn and winter (12 mmol m - 2 day - 1 ). Modeled ventilation and net CO 2

  10. Effects of Radon Inhalation on Some Biophysical Properties of Blood in Rats

    NASA Astrophysics Data System (ADS)

    Essa, M. F.; Shahin, Fayez M.; Ahmed, Ashour M.; Abdel-Salam, Omar

    2013-03-01

    The major source of human exposure to natural radiation arises from the inhalation of radon (222Rn) gas. Exposure to high concentrations of radon 222Rn and its daughters for long period leads to pathological effects like lung cancer, leukaemia, skin cancer and kidney diseases. The present study was performed on rats to investigate the effect of radon exposure on the absorption spectra of hemoglobin. Measurements have been performed in a radon chamber where rats were exposed to radon for 1, 5 or 7 weeks. The inhalation of radon resulted in decrease in intensity of the absorption bands characterizing the hemoglobin molecular structure with increased radon doses.

  11. Environmental radon and cancer correlations in Maine.

    PubMed

    Hess, C T; Weiffenbach, C V; Norton, S A

    1983-08-01

    The distribution of 222Rn has been measured in the sixteen counties of Maine, U.S.A. by liquid scintillation counting of water samples from more than two thousand public and private wells. Three hundred and fifty of these wells have been characterized for geology and hydrology. Airborne radon has been measured in seventy houses with grab samples and in eighteen houses for 5-7 days each with continuously recording diffusion-electrostatic radon detectors. Concentrations of radon in water ranged from 20 to 180,000 pCi/l. Granite areas yielded the highest average levels (mean = 22,100 pCi/l.; n = 136), with considerable intra-granite variation. Metasedimentary rocks yielded levels characteristic of the lithology for metamorphic grades ranging from chlorite to andalusite. Sillimanite and higher-grade rocks yielded higher 222Rn levels, probably due to the intrusion of uranium-bearing pegmatites in these terranes. Airborne 222Rn in homes ranged from 0.05 to 210 pCi/l. At the high end of this range, doses will exceed recommended industrial limits. In some homes only a small fraction of the airborne 222Rn was due to the water supply. Average 222Rn levels in domestic water supplies for each of the 16 counties, calculated by areally averaging rock types and their associated 222Rn levels, were found to be significantly correlated with rates for all cancers combined and rates for lung and reproductive cancers in the counties. Although numerous factors other than cancer induction by indoor daughter exposures may be responsible for the observed correlations, these have not been investigated in detail. PMID:6885433

  12. Using geochemical tracers to distinguish groundwater and parafluvial inflows in rivers (the Avon Catchment, SE Australia)

    NASA Astrophysics Data System (ADS)

    Cartwright, I.; Hofmann, H.

    2015-09-01

    Understanding the location and magnitude of groundwater inflows to rivers is important for the protection of riverine ecosystems and the management of connected groundwater and surface water systems. Downstream trends in 222Rn activities and Cl concentrations in the Avon River, southeast Australia, implies that it contains alternating gaining and losing reaches. 222Rn activities of up to 3690 Bq m-3 imply that inflows are locally substantial (up to 3.1 m3 m-1 day-1). However, if it assumed that these inflows are solely from groundwater, the net groundwater inflows during low-flow periods exceed the measured increase in streamflow along the Avon River by up to 490 %. Uncertainties in the 222Rn activities of groundwater, the gas transfer coefficient, and the degree of hyporheic exchange cannot explain this discrepancy. It is proposed that a significant volume of the total calculated inflows into the Avon River represents water that exfiltrates from the river, flows through parafluvial sediments, and subsequently re-enters the river in the gaining reaches. This returning parafluvial flow has high 222Rn activities due to 222Rn emanations from the alluvial sediments. The riffle sections of the Avon River commonly have steep longitudinal gradients and may transition from losing at their upstream end to gaining at the downstream end and parafluvial flow through the sediment banks on meanders and point bars may also occur. Parafluvial flow is likely to be important in rivers with coarse-grained alluvial sediments on their floodplains and failure to quantify the input of 222Rn from parafluvial flow will result in overestimating groundwater inflows to rivers.

  13. Factors affecting indoor radon concentrations in the United Kingdom.

    PubMed

    Gunby, J A; Darby, S C; Miles, J C; Green, B M; Cox, D R

    1993-01-01

    Data collected in a nationwide study on natural radiation exposure in UK dwellings (Wrixon et al. 1988) were re-analyzed to investigate the effects of rock type and various building and lifestyle characteristics, taken into account simultaneously, on indoor radon concentrations. A multiplicative model which takes into consideration the outdoor radon concentration is used. Indoor radon concentrations were found to be influenced by type of rock underlying the dwelling, double glazing, house type, floor level of rooms in which measurements were taken, window opening habits in the main bedroom, building materials used in the construction of the walls, floor type, and draught proofing. However, these eight factors together account for only 22% of the variation between dwellings. Estimates of the size of the effect associated with each factor are given. PMID:8416211

  14. Mining User Dwell Time for Personalized Web Search Re-Ranking

    SciTech Connect

    Xu, Songhua; Jiang, Hao; Lau, Francis

    2011-01-01

    We propose a personalized re-ranking algorithm through mining user dwell times derived from a user's previously online reading or browsing activities. We acquire document level user dwell times via a customized web browser, from which we then infer conceptword level user dwell times in order to understand a user's personal interest. According to the estimated concept word level user dwell times, our algorithm can estimate a user's potential dwell time over a new document, based on which personalized webpage re-ranking can be carried out. We compare the rankings produced by our algorithm with rankings generated by popular commercial search engines and a recently proposed personalized ranking algorithm. The results clearly show the superiority of our method. In this paper, we propose a new personalized webpage ranking algorithmthrough mining dwell times of a user. We introduce a quantitative model to derive concept word level user dwell times from the observed document level user dwell times. Once we have inferred a user's interest over the set of concept words the user has encountered in previous readings, we can then predict the user's potential dwell time over a new document. Such predicted user dwell time allows us to carry out personalized webpage re-ranking. To explore the effectiveness of our algorithm, we measured the performance of our algorithm under two conditions - one with a relatively limited amount of user dwell time data and the other with a doubled amount. Both evaluation cases put our algorithm for generating personalized webpage rankings to satisfy a user's personal preference ahead of those by Google, Yahoo!, and Bing, as well as a recent personalized webpage ranking algorithm.

  15. The cost effectiveness of radon mitigation in existing German dwellings--a decision theoretic analysis.

    PubMed

    Haucke, Florian

    2010-11-01

    Radon is a naturally occurring inert radioactive gas found in soils and rocks that can accumulate in dwellings, and is associated with an increased risk of lung cancer. This study aims to analyze the cost effectiveness of different intervention strategies to reduce radon concentrations in existing German dwellings. The cost effectiveness analysis (CEA) was conducted as a scenario analysis, where each scenario represents a specific regulatory regime. A decision theoretic model was developed, which reflects accepted recommendations for radon screening and mitigation and uses most up-to-date data on radon distribution and relative risks. The model was programmed to account for compliance with respect to the single steps of radon intervention, as well as data on the sensitivity/specificity of radon tests. A societal perspective was adopted to calculate costs and effects. All scenarios were calculated for different action levels. Cost effectiveness was measured in costs per averted case of lung cancer, costs per life year gained and costs per quality adjusted life year (QALY) gained. Univariate and multivariate deterministic and probabilistic sensitivity analyses (SA) were performed. Probabilistic sensitivity analyses were based on Monte Carlo simulations with 5000 model runs. The results show that legal regulations with mandatory screening and mitigation for indoor radon levels >100 Bq/m(3) are most cost effective. Incremental cost effectiveness compared to the no mitigation base case is 25,181 euro (95% CI: 7371 euro-90,593 euro) per QALY gained. Other intervention strategies focussing primarily on the personal responsibility for screening and/or mitigative actions show considerably worse cost effectiveness ratios. However, targeting radon intervention to radon-prone areas is significantly more cost effective. Most of the uncertainty that surrounds the results can be ascribed to the relative risk of radon exposure. It can be concluded that in the light of

  16. Prevalence of Cognitive Impairment in Community-Dwelling Older Adults

    PubMed Central

    Rashedi, Vahid; Rezaei, Mohammad; Gharib, Masoud

    2014-01-01

    Introduction Mild cognitive impairment can be considered as an intermediate clinical state between normal cognitive aging and mild dementia. Elderly people with this impairment represent an at-risk group for the development of dementia. The aim of this study was to investigate the prevalence of cognitive impairment in community-dwelling older adults by Mini-Mental State Examination (MMSE) and its relationship with socio-demographic variables. Methods In this analytical-descriptive study, 212 subjects admitted to Hamadan’s day care centers were selected through simple random sampling method. To gather the data, MMSE was used as well as a questionnaire containing demographic variables. Data analysis was completed through SPSS-16. Results The sample consisted of 17.9% male, 59.4% of whom were married. According to the results, 96 cases (45.3%) suffered from mild (MMSE≥22), 110 cases (51.9%) from moderate (11≤MMSE≤21) and 6 cases (2.8%) from severe cognitive disorder (MMSE≤10). As findings revealed, factors such as age (Pv = 0.005, r = -0.491) and schooling (Pv < 0.001) are of significant relationship with MMSE score. Discussion Prevalence of cognitive decline in community-dwelling older adults was of normal range. Hence, familial relations and social support can decrease mental status disorder. PMID:25436081

  17. Prevalence and risk factors of depression among community dwelling elderly.

    PubMed

    Yaka, Erdem; Keskinoglu, Pembe; Ucku, Reyhan; Yener, Görsev Gülmen; Tunca, Zeliha

    2014-01-01

    Depression in the elderly is associated with increased morbidity and mortality. The purpose of this study was to determine the prevalence and risk factors of depression among community-dwelling older population in an urban setting in Turkey. This cross-sectional study was conducted among 482 elderly individuals 65 years and over in an urban area. Cluster sampling method was used for sample size. Depression in the elderly had been diagnosed by a clinical interview and Geriatric Depression Scale. Data were collected by door-to-door survey. Chi square test was used for statistical analysis. P value, which was calculated by the results of chi square test and coefficient of phi (φ), below 0.05 was included in the analysis of logistic regression. Depression was significantly associated with female gender, being single or divorced, lower educational status, low income, unemployment, and lack of health insurance. However, logistic regression analysis revealed higher depression rates in the elderly with chronic obstructive pulmonary disease, psychiatric disease, cerebrovascular disease, low income and being dependent. Depression is common among community-dwelling older people in an urban area of Izmir, Turkey. Older adults living in community should be cautiously screened to prevent or manage depression. PMID:24767692

  18. Environmental constraints and call evolution in torrent-dwelling frogs.

    PubMed

    Goutte, Sandra; Dubois, Alain; Howard, Samuel D; Marquez, Rafael; Rowley, Jodi J L; Dehling, J Maximilian; Grandcolas, Philippe; Rongchuan, Xiong; Legendre, Frédéric

    2016-04-01

    Although acoustic signals are important for communication in many taxa, signal propagation is affected by environmental properties. Strong environmental constraints should drive call evolution, favoring signals with greater transmission distance and content integrity in a given calling habitat. Yet, few empirical studies have verified this prediction, possibly due to a shortcoming in habitat characterization, which is often too broad. Here we assess the potential impact of environmental constraints on the evolution of advertisement call in four groups of torrent-dwelling frogs in the family Ranidae. We reconstruct the evolution of calling site preferences, both broadly categorized and at a finer scale, onto a phylogenetic tree for 148 species with five markers (∼3600 bp). We test models of evolution for six call traits for 79 species with regard to the reconstructed history of calling site preferences and estimate their ancestral states. We find that in spite of existing morphological constraints, vocalizations of torrent-dwelling species are most probably constrained by the acoustic specificities of torrent habitats and particularly their high level of ambient noise. We also show that a fine-scale characterization of calling sites allows a better perception of the impact of environmental constraints on call evolution. PMID:26960074

  19. Quality control of mitigation methods for unusually high indoor radon concentrations.

    PubMed

    Huber, J; Ennemoser, O; Schneider, P

    2001-08-01

    The present study's objective was to control the quality of different mitigation methods for unusually high indoor radon (222Rn) concentrations of up to 274,000 Bq m(-3) in a village (Umhausen, 2,600 inhabitants) in western Tyrol, Austria. Five years after mitigation, five different remedial actions were examined on their quality by means of measuring indoor radon concentrations with charcoal liquid scintillation radon detectors and with a continuously recording AlphaGuard detector. Mitigation method in house 1--a mechanical intake and outlet ventilation system with heat exchanger in the basement, combined with a soil depressurization system--was characterized by long-term stability. With most favorable air pressure (+100 Pa) in the basement, mean basement radon concentrations in the winter were reduced from 200,000 Bq m(-3) to 3,000 Bq m(-3) by this method 5 y after mitigation. Acting against experts' instructions, the inhabitants had switched off the ventilation system most of the time to minimize power consumption although it had been proven that ventilation reduced mean basement radon concentration by a factor of about 3 in the winter and about 15 in the summer. Mitigation method in house 2-soil depressurization with two fans and loops of drainage tubes to withdraw radon from the region below the floor and outside the basement walls, and from soil below that part of the house with no basement-had been the most successful remedial measure until the winter of 1999 (i.e., 6 y after mitigation), when micro-cracks opened and consequently mean basement radon concentration increased from 250 Bq m(-3) to 1,500 Bq m(-3). Measures to block these microcracks and to minimize soil drying are being developed. Five years after mitigation, the remedial method used in house 3--a multilayer floor construction, where a fan was used to suck radon from a layer between bottom slab and floor-reduced winter mean radon concentration from 25,000 Bq m(-3) to 1,200 Bq m(-3), with the

  20. Factors influencing detection of eDNA from a stream-dwelling amphibian

    USGS Publications Warehouse

    Pilliod, David S.; Goldberg, Caren S.; Arkle, Robert S.; Waits, Lisette P.

    2013-01-01

    Environmental DNA (eDNA) methods for detecting and estimating abundance of aquatic species are emerging rapidly, but little is known about how processes such as secretion rate, environmental degradation, and time since colonization or extirpation from a given site affect eDNA measurements. Using stream-dwelling salamanders and quantitative PCR (qPCR) analysis, we conducted three experiments to assess eDNA: (i) production rate; (ii) persistence time under different temperature and light conditions; and (iii) detectability and concentration through time following experimental introduction and removal of salamanders into previously unoccupied streams. We found that 44–50 g individuals held in aquaria produced 77 ng eDNA/h for 2 h, after which production either slowed considerably or began to equilibrate with degradation. eDNA in both full-sun and shaded treatments degraded exponentially to 2) and when samples were collected within 5 m of the animals. Concentrations of eDNA detected were very low and increased steadily from 6–24 h after introduction, reaching 0.0022 ng/L. Within 1 h of removing salamanders from the stream, eDNA was no longer detectable. These results suggest that eDNA detectability and concentration depend on production rates of individuals, environmental conditions, density of animals, and their residence time.

  1. 25 CFR 91.7 - Permits to occupy land for dwelling purposes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Permits to occupy land for dwelling purposes. 91.7 Section 91.7 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR TRIBAL GOVERNMENT GOVERNMENT OF INDIAN VILLAGES, OSAGE RESERVATION, OKLAHOMA § 91.7 Permits to occupy land for dwelling purposes....

  2. 25 CFR 91.7 - Permits to occupy land for dwelling purposes.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Permits to occupy land for dwelling purposes. 91.7 Section 91.7 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR TRIBAL GOVERNMENT GOVERNMENT OF INDIAN VILLAGES, OSAGE RESERVATION, OKLAHOMA § 91.7 Permits to occupy land for dwelling purposes....

  3. 25 CFR 91.7 - Permits to occupy land for dwelling purposes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Permits to occupy land for dwelling purposes. 91.7 Section 91.7 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR TRIBAL GOVERNMENT GOVERNMENT OF INDIAN VILLAGES, OSAGE RESERVATION, OKLAHOMA § 91.7 Permits to occupy land for dwelling purposes....

  4. 25 CFR 91.7 - Permits to occupy land for dwelling purposes.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Permits to occupy land for dwelling purposes. 91.7 Section 91.7 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR TRIBAL GOVERNMENT GOVERNMENT OF INDIAN VILLAGES, OSAGE RESERVATION, OKLAHOMA § 91.7 Permits to occupy land for dwelling purposes....

  5. 25 CFR 91.7 - Permits to occupy land for dwelling purposes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Permits to occupy land for dwelling purposes. 91.7 Section 91.7 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR TRIBAL GOVERNMENT GOVERNMENT OF INDIAN VILLAGES, OSAGE RESERVATION, OKLAHOMA § 91.7 Permits to occupy land for dwelling purposes....

  6. 24 CFR 206.51 - Eligibility of mortgages involving a dwelling unit in a condominium.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... a dwelling unit in a condominium. 206.51 Section 206.51 Housing and Urban Development Regulations... UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES HOME EQUITY CONVERSION MORTGAGE INSURANCE Eligibility; Endorsement Eligible Properties § 206.51 Eligibility of mortgages involving a dwelling unit in a...

  7. 25 CFR 700.155 - Expenses in searching for replacement dwelling-residential move.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Expenses in searching for replacement dwelling... Expenses in searching for replacement dwelling—residential move. (a) A certified eligible head of household is entitled to actual reasonable expenses incurred in the search for a replacement dwelling....

  8. 25 CFR 700.155 - Expenses in searching for replacement dwelling-residential move.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 2 2012-04-01 2012-04-01 false Expenses in searching for replacement dwelling... Expenses in searching for replacement dwelling—residential move. (a) A certified eligible head of household is entitled to actual reasonable expenses incurred in the search for a replacement dwelling....

  9. 25 CFR 700.155 - Expenses in searching for replacement dwelling-residential move.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 2 2014-04-01 2014-04-01 false Expenses in searching for replacement dwelling... Expenses in searching for replacement dwelling—residential move. (a) A certified eligible head of household is entitled to actual reasonable expenses incurred in the search for a replacement dwelling....

  10. 25 CFR 700.155 - Expenses in searching for replacement dwelling-residential move.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 2 2013-04-01 2013-04-01 false Expenses in searching for replacement dwelling... Expenses in searching for replacement dwelling—residential move. (a) A certified eligible head of household is entitled to actual reasonable expenses incurred in the search for a replacement dwelling....

  11. 25 CFR 700.155 - Expenses in searching for replacement dwelling-residential move.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Expenses in searching for replacement dwelling... Expenses in searching for replacement dwelling—residential move. (a) A certified eligible head of household is entitled to actual reasonable expenses incurred in the search for a replacement dwelling....

  12. Dwell Notch Low Cycle Fatigue Behavior of a Powder Metallurgy Nickel Disk Alloy

    NASA Technical Reports Server (NTRS)

    Telesman, J.; Gabb, T. P.; Yamada, Y.; Ghosn, L. J.; Jayaraman, N.

    2012-01-01

    A study was conducted to determine the processes which govern dwell notch low cycle fatigue (NLCF) behavior of a powder metallurgy (P/M) ME3 disk superalloy. The emphasis was placed on the environmentally driven mechanisms which may embrittle the highly stressed notch surface regions and reduce NLCF life. In conjunction with the environmentally driven notch surface degradation processes, the visco-plastic driven mechanisms which can significantly change the notch root stresses were also considered. Dwell notch low cycle fatigue testing was performed in air and vacuum on a ME3 P/M disk alloy specimens heat treated using either a fast or a slow cooling rate from the solutioning treatment. It was shown that dwells at the minimum stress typically produced a greater life debit than the dwells applied at the maximum stress, especially for the slow cooled heat treatment. Two different environmentally driven failure mechanisms were identified as the root cause of early crack initiation in the min dwell tests. Both of these failure mechanisms produced mostly a transgranular crack initiation failure mode and yet still resulted in low NLCF fatigue lives. The lack of stress relaxation during the min dwell tests produced higher notch root stresses which caused early crack initiation and premature failure when combined with the environmentally driven surface degradation mechanisms. The importance of environmental degradation mechanisms was further highlighted by vacuum dwell NLCF tests which resulted in considerably longer NLCF lives, especially for the min dwell tests.

  13. Relationship between Perceived Needs and Assessed Needs for Services in Community-Dwelling Older Persons

    ERIC Educational Resources Information Center

    Cohen-Mansfield, Jiska; Frank, Julia

    2008-01-01

    Purpose: We examine the relationship between the perceived needs and assessed needs of community-dwelling seniors. Design and Methods: Trained research assistants administered the Naturally Occurring Retirement Community Baseline Survey to 268 community-dwelling older adults in suburban Maryland. Perceived and assessed needs were measured in the…

  14. Estimating ground-water influx to a portion of the Rio Grande de Manati River basin in Puerto Rico through the measurement of 222Rn

    USGS Publications Warehouse

    Ellins, K.K.; Roman-Mas, Angel; Lee, Roger W.

    1986-01-01

    Water has become a critical commodity in the Caribbean Region. In spite of a relative abundance of rainfall even on the smaller islands, the region is faced with severe seasonal shortages as well as increasing water quality problems. The supply of thewater needs in the area will become even more critical as economic development accelerates and the population continues to increase. The development of the necessary infrastructure to supply the water needs of the next 30 years will require large capital investments. Perhaps even more important, it will require training of scientists and technicians in the investigation and management of the limited waterresources. The lack of trained personnel could be the most important factor in the solution of the water resources problems in the region. The principal objectives of this ' Third Caribbean Islands Water Resources Congress ', were to provide a focus for the transfer of technology on hydrology and water resources investigations in the region. The severe quality problems that affect water supplies in the U.S. Virgin Islands are the subject of two papers. The importance of a reliable data base on water use in small islands is considered in a paper on water use in St. Croix. Advanced techniques are discussed on how to measure groundwater contributions to runoff, use of geochemical techniques for interpretation of water quality characteristics, use of dye tracers in karst areas, simulation of small island 's aquifers, and use of borehole geophysical tools to estimate moisture. The contamination of groundwater resources is discussed in several papers focusing on monitoring, sludge management, and environmental assessment. (See W89-04666 thru W89-04682) (Lantz-PTT) 

  15. Patterns of behaviour in dwellings exposed to road traffic noise

    NASA Astrophysics Data System (ADS)

    Lambert, J.; Simonnet, F.; Vallet, M.

    1984-01-01

    An inquiry involving a total of 1500 subjects residing in 15 different sites in the conurbations of Lyon and Marseilles was carried out in 1979 with a view to determining the behaviour and attitudes of people with regard to traffic noise. The main purpose of the inquiry was to identify the objective reactions to the traffic noise and to determine how such reactions varied with the noise level, with account taken of the socio-economic characteristics of the subjects (age, income, owner occupier or tenant, etc.). The 08.00-20.00 hour Leq noise level was measured or calculated for each of the dwellings included in the inquiry. The 00.00-05.00 and 20.00-24.00 hour Leq values were also derived for each case and a total of nearly 20 000 different noise levels were involved in the analysis of the data for this inquiry. On considering the completed questionaires it was found that the annoyance experienced during the day was more closely correlated with the noise level ( r = 0·64) than had been the case with the results of previous studies. In addition to showing how traffic noise can interfere with activities and lead, for example, to the closing of windows to shut out the noise, the inquiry yielded information on the way in which activities affected by noise are transferred to quieter rooms, on the extent to which individual dwellings are sound proofed, on the extent to which occupants are likely to move to another dwelling in order to escape from the noise and finally on some aspects of the effects of noise on health and sleep. Thus it appears that a daytime Leq value of more than 65 dB(A) gives rise to what can be regarded as forced behavioural responses to the extent that there are significant changes in the normal way of life of the people concerned and such responses give an indication of the magnitude of the social costs that can be attributed to the undesirable effects of traffic noise.

  16. Dwell-time-limited coherence in open quantum dots.

    PubMed

    Hackens, B; Faniel, S; Gustin, C; Wallart, X; Bollaert, S; Cappy, A; Bayot, V

    2005-04-15

    We present measurements of the electron phase coherence time tau(varphi) on a wide range of open ballistic quantum dots (QDs) made from InGaAs heterostructures. The observed saturation of tau(varphi) below temperatures 0.5 Kdwell time becomes the limiting factor for electron interference effects in QDs at low temperature. PMID:15904090

  17. Dwell-Time-Limited Coherence in Open Quantum Dots

    NASA Astrophysics Data System (ADS)

    Hackens, B.; Faniel, S.; Gustin, C.; Wallart, X.; Bollaert, S.; Cappy, A.; Bayot, V.

    2005-04-01

    We present measurements of the electron phase coherence time τϕ on a wide range of open ballistic quantum dots (QDs) made from InGaAs heterostructures. The observed saturation of τϕ below temperatures 0.5 Kdwell time becomes the limiting factor for electron interference effects in QDs at low temperature.

  18. Technology Solutions Case Study: Predicting Envelope Leakage in Attached Dwellings

    SciTech Connect

    2013-11-01

    The most common method of measuring air leakage is to perform single (or solo) blower door pressurization and/or depressurization test. In detached housing, the single blower door test measures leakage to the outside. In attached housing, however, this “solo” test method measures both air leakage to the outside and air leakage between adjacent units through common surfaces. In an attempt to create a simplified tool for predicting leakage to the outside, Building America team Consortium for Advanced Residential Buildings (CARB) performed a preliminary statistical analysis on blower door test results from 112 attached dwelling units in four apartment complexes. Although the subject data set is limited in size and variety, the preliminary analyses suggest significant predictors are present and support the development of a predictive model. Further data collection is underway to create a more robust prediction tool for use across different construction types, climate zones, and unit configurations.

  19. Predictive Mortality Index for Community-Dwelling Elderly Koreans

    PubMed Central

    Kim, Nan H.; Cho, Hyun J.; Kim, Soriul; Seo, Ji H.; Lee, Hyun J.; Yu, Ji H.; Chung, Hye S.; Yoo, Hye J.; Seo, Ji A.; Kim, Sin Gon; Baik, Sei Hyun; Choi, Dong Seop; Shin, Chol; Choi, Kyung Mook

    2016-01-01

    Abstract There are very few predictive indexes for long-term mortality among community-dwelling elderly Asian individuals, despite its importance, given the rapid and continuous increase in this population. We aimed to develop 10-year predictive mortality indexes for community-dwelling elderly Korean men and women based on routinely collected clinical data. We used data from 2244 elderly individuals (older than 60 years of age) from the southwest Seoul Study, a prospective cohort study, for the development of a prognostic index. An independent longitudinal cohort of 679 elderly participants was selected from the Korean Genome Epidemiology Study in Ansan City for validation. During a 10-year follow-up, 393 participants (17.5%) from the development cohort died. Nine risk factors were identified and weighed in the Cox proportional regression model to create a point scoring system: age, male sex, smoking, diabetes, systolic blood pressure, triglyceride, total cholesterol, white blood cell count, and hemoglobin. In the development cohort, the 10-year mortality risk was 6.6%, 14.8%, 18.2%, and 38.4% among subjects with 1 to 4, 5 to 7, 8 to 9, and ≥10 points, respectively. In the validation cohort, the 10-year mortality risk was 5.2%, 12.0%, 16.0%, and 16.0% according to these categories. The C-statistic for the point system was 0.73 and 0.67 in the development and validation cohorts, respectively. The present study provides valuable information for prognosis among elderly Koreans and may guide individualized approaches for appropriate care in a rapidly aging society. PMID:26844511

  20. Extracting Dwell Time Sequences from Processive Molecular Motor Data

    PubMed Central

    Milescu, Lorin S.; Yildiz, Ahmet; Selvin, Paul R.; Sachs, Frederick

    2006-01-01

    Processive molecular motors, such as kinesin, myosin, or dynein, convert chemical energy into mechanical energy by hydrolyzing ATP. The mechanical energy is used for moving in discrete steps along the cytoskeleton and carrying a molecular load. Single-molecule recordings of motor position along a substrate polymer appear as a stochastic staircase. Recordings of other single molecules, such as F1-ATPase, RNA polymerase, or topoisomerase, have the same appearance. We present a maximum likelihood algorithm that extracts the dwell time sequence from noisy data, and estimates state transition probabilities and the distribution of the motor step size. The algorithm can handle models with uniform or alternating step sizes, and reversible or irreversible kinetics. A periodic Markov model describes the repetitive chemistry of the motor, and a Kalman filter allows one to include models with variable step size and to correct for baseline drift. The data are optimized recursively and globally over single or multiple data sets, making the results objective over the full scale of the data. Local binary algorithms, such as the t-test, do not represent the behavior of the whole data set. Our method is model-based, and allows rapid testing of different models by comparing the likelihood scores. From data obtained with current technology, steps as small as 8 nm can be resolved and analyzed with our method. The kinetic consequences of the extracted dwell sequence can be further analyzed in detail. We show results from analyzing simulated and experimental kinesin and myosin motor data. The algorithm is implemented in the free QuB software. PMID:16905607

  1. Teeth and physical fitness in a community-dwelling 40 to 79-year-old Japanese population

    PubMed Central

    Inui, Akinari; Takahashi, Ippei; Sawada, Kaori; Naoki, Akimoto; Oyama, Toshirou; Tamura, Yoshihiro; Osanai, Toshiyuki; Satake, Anna; Nakaji, Shigeyuki; Kobayashi, Wataru

    2016-01-01

    Purpose Decline in the number of teeth and physical fitness begins from 40 years of age; however, several epidemiological studies have identified relationships between oral conditions and physical performance parameters in community-dwelling elderly population. The aim of this study was to validate the relationship between the muscle mass and its function and oral conditions (number of teeth and dental occlusion) after 40 years of age in a community-dwelling population in Japan. Materials and methods The subjects comprised of 552 volunteers (198 males and 354 females, 40–79 years) who participated in the Iwaki Health Promotion Project in 2013. Multiple linear regression analyses were performed with the measures of the muscle mass and its function as objective variables and the measures of the number of teeth, age, body mass index, medical history, serum albumin concentration, smoking status, habitual alcohol intake, marital status, education levels, and exercising habits as explanatory variables. The relationships between the Eichner index and the muscle mass and its function were analyzed using analysis of covariance, with adjustment for confounding factors. Results After adjusting for confounding factors, the number of teeth was shown to be an independent risk factor for the timed 10 m walk test (in females) and the skeletal muscle mass of the whole body (in males). The results also revealed that the timed 10 m walk test was significantly correlated with the Eichner index (Classes A and C in females were correlated). Conclusion This cross-sectional study on a Japanese community-dwelling population revealed relationships between oral conditions and the muscle mass and its function. However, the interpretation of our results was hampered by a lack of data, including those on socioeconomic status and longitudinal observations. Future research exploring teeth loss and the muscle mass and its function is warranted. PMID:27418813

  2. Characterizing the effects of bisphenol A on sediment-dwelling benthic organisms.

    PubMed

    Staples, Charles; Mihaich, Ellen; Ortego, Lisa; Caspers, Norbert; Klečka, Gary; Woelz, Jan; Hentges, Steven

    2016-03-01

    Bisphenol A (BPA) is a high production volume chemical intermediate used primarily in the production of polycarbonate plastics and epoxy resins. It primarily enters surface water and sediment via effluent discharges during its manufacture and use. The physical properties of BPA suggest that sediment is a potential sink and may result in exposure to benthic organisms. Currently there are no studies measuring the chronic toxicity of BPA to benthic organisms via direct sediment exposure. The present study examined the chronic toxicity of BPA to 3 commonly used test organisms that are generally representative of invertebrates occupying the base of the benthic food web and for which standardized testing protocols are available: the oligochaete Lumbriculus variegatus (mean numbers and biomass), the midge Chironomus riparius (emergence and development rate), and the estuarine amphipod Leptocheirus plumulosus (survival, growth, and reproduction). No-observed-effect concentrations (NOECs) for the 3 species ranged from 12 mg/kg to 54 mg/kg dry weight. All NOEC values were higher than all measured concentrations of BPA in freshwater and marine sediments reported in reliable, fully reported studies from North America and Europe from the 1990s to the present. For the first time, there are studies with BPA measuring the chronic toxicity to 3 taxa of sediment dwelling invertebrates, which are suitable to support region-specific risk assessments. PMID:26297924

  3. Assessment of the effect of nanomaterials on sediment-dwelling invertebrate Chironomus tentans larvae.

    PubMed

    Oberholster, P J; Musee, N; Botha, A-M; Chelule, P K; Focke, W W; Ashton, P J

    2011-03-01

    Studies were conducted to determine the effects of a panel of seven nanomaterials (NMs), namely: α-alumina, γ-alumina, precipitated silica; silica fume, calcined silica fume, colloidal antimony pentoxide (Sb(2)O(5)), and superfine amorphous ferric oxide (Fe(2)O(3)), on sediment dwelling invertebrates Chironomus tentans under controlled laboratory conditions. Percentage survival, enzyme activities, growth development, and DNA fragmentation parameters were studied as acute, biochemical, and physiological toxicities of NMs, respectively. Quantitation of catalase and peroxidase enzyme activity demonstrated that toxicant stress of the NMs increased enzyme activity in a concentration dependent fashion across all treatments. The percentage growth length of the test specimens exposed to different NMs was significantly reduced compared to the negative control while only five concentrations were not in the toxic range, namely; Fe(2)O(3) (5 μg/kg); silica fume (5 μg/kg, 50 μg/kg); Sb(2)O(5) (5 μg/kg) and calcined silica fume (5 μg/kg). Genotoxic stress assessed by use of DNA laddering showed complementary findings to the other ecotoxicological endpoints tested in this study--the percentage survival and growth length inhibition. PMID:21216008

  4. Effective Dose of Radon 222 Bottled Water in Different Age Groups Humans: Bandar Abbas City, Iran.

    PubMed

    Fakhri, Yadolah; Mahvi, Amir Hossein; Langarizadeh, Ghazaleh; Zandsalimi, Yahya; Amirhajeloo, Leila Rasouli; Kargosha, Morteza; Moradi, Mahboobeh; Moradi, Bigard; Mirzaei, Maryam

    2016-01-01

    Radon 222 is a natural radioactive element with a half-life of 3.8 days. It is odorless and colorless as well as water-soluble. Consuming waters which contain high concentration of 222Rn would increase the effective dose received by different age groups. It would also be followed by an increased prevalence of cancer. In this research, 72 samples of the most commonly used bottled water in Bandar Abbas were collected in 3 consecutive months, May, June and July of 2013. Concentration 222Rn of was measured by radon-meter model RTM166-2. The effective dose received by the 4 age groups, male and female adults as well as children and infants was estimated using the equation proposed by UNSCEAR. The results revealed that the mean and range concentration of 222Rn in bottled waters were 641±9 Bq/m3 and 0-901 Bq/m3, respectively. The mean concentration of 222Rn in the well-known Marks followed this Zam Zam>Bishe>Koohrng>Dassani>Christal>Polour>Damavand>Sivan. Infants were observed to receive a higher effective dose than children. The highest and lowest effective dose received was found to belong to male adults and children, respectively. PMID:26383192

  5. Effective Dose of Radon 222 Bottled Water in Different Age Groups Humans: Bandar Abbas City, Iran

    PubMed Central

    Fakhri, Yadolah; Mahvi, Amir Hossein; Langarizadeh, Ghazaleh; Zandsalimi, Yahya; Amirhajeloo, Leila Rasouli; Kargosha, Morteza; Moradi, Mahboobeh; Moradi, Bigard; Mirzaei, Maryam

    2016-01-01

    Radon 222 is a natural radioactive element with a half-life of 3.8 days. It is odorless and colorless as well as water-soluble. Consuming waters which contain high concentration of 222Rn would increase the effective dose received by different age groups. It would also be followed by an increased prevalence of cancer. In this research, 72 samples of the most commonly used bottled water in Bandar Abbas were collected in 3 consecutive months, May, June and July of 2013. Concentration 222Rn of was measured by radon-meter model RTM166-2. The effective dose received by the 4 age groups, male and female adults as well as children and infants was estimated using the equation proposed by UNSCEAR. The results revealed that the mean and range concentration of 222Rn in bottled waters were 641±9 Bq/m3 and 0-901 Bq/m3, respectively. The mean concentration of 222Rn in the well-known Marks followed this Zam Zam>Bishe>Koohrng>Dassani>Christal>Polour>Damavand>Sivan. Infants were observed to receive a higher effective dose than children. The highest and lowest effective dose received was found to belong to male adults and children, respectively. PMID:26383192

  6. Influence of Submarine Groundwater Discharge on Primary Productivity in the Semi-Enclosed Bay in Japan

    NASA Astrophysics Data System (ADS)

    Sugimoto, R.; Nishi, S.; Taniguchi, M.; Tominaga, O.

    2014-12-01

    In recent years, a number of studies have shown that submarine groundwater discharge is an alternative nutrient pathway and can drive primary production in coastal seas. However, very little is known about an exact relationship between input of groundwater and response of primary production. To clarify the relationship, we conducted the field survey in the semi-enclosed coastal bay in Japan (Obama Bay). There are abundant amounts of groundwater resources in the basin. Firstly, we conducted 222Rn continuous measurement along the coast in March 2013 to obtain the spatial difference of groundwater impact. As a result, 222Rn activity clearly showed that groundwater discharge concentrates in the western part of the bay head. We thus conducted in-situ measurements of primary productivity using stable 13C tracer method and environmental parameters (ex. 222Rn activity, light intensity, temperature and nutrient concentrations) at 6 stations within the western bay head in July and August 2013. Primary productivity within the western bay head changed from 11.0 to 49.5 μg C L-1 hr-1 in July and from 9.3 to 32.4 μg C L-1 hr-1 in August. Moreover, there was significant relationship between primary productivity and 222Rn concentration in both months. Although light intensity and water temperature were different in each station and month, concentrations of nutrients limited primary productivity. These results showed that nutrient supply from SGD would affect crucial impact on primary productivity in Obama Bay.

  7. PROGRESS REPORT. MEASUREMENTS OF RADON, THORON, ISOTOPIC URANIUM AND THORIUM TO DETERMINE OCCUPATIONAL & ENVIRONMENTAL EXPOSURE & RISK AT FERNALD FEED MATERIALS PRODUCTION CENTER

    EPA Science Inventory

    There are three basic research objectives: (1) To develop an accurate personal and area radon/thoron (222Rn/220Rn) detector for accurate measurement of the exposure to low airborne concentrations of these gases during remediation at Fernald. These are to be used to determine atmo...

  8. Social and Spatial Networks: Kinship Distance and Dwelling Unit Proximity in Rural Thailand

    PubMed Central

    Verdery, Ashton M.; Entwisle, Barbara; Faust, Katherine; Rindfuss, Ronald R.

    2013-01-01

    We address a long hypothesized relationship between the proximity of individuals' dwelling units and their kinship association. Better understanding this relationship is important because of its implications for contact and association among members of a society. In this paper, we use a unique dataset from Nang Rong, Thailand which contains dwelling unit locations (GPS) and saturated kinship networks of all individuals living in 51 agricultural villages. After presenting arguments for a relationship between individuals’ dwelling unit locations and their kinship relations as well as the particulars of our case study, we introduce the data and describe our analytic approach. We analyze how kinship - considered as both a system linking collections of individuals in an extended kinship network and as dyadic links between pairs of individuals -patterns the proximity of dwelling units in rural villages. The results show that in general, extended kin live closer to one another than do unrelated individuals. Further, the degree of relatedness between kin correlates with the distance between their dwelling units. Close kin are more likely to co-reside, a fact which drives much of the relationship between kinship relatedness and dwelling unit proximity within villages. There is nevertheless suggestive evidence of a relationship between kinship association and dwelling unit proximity among kin who do not live together. PMID:23956489

  9. Resveratrol levels and all-cause mortality in older community-dwelling adults

    PubMed Central

    Semba, Richard D.; Ferrucci, Luigi; Bartali, Benedetta; Urpí-Sarda, Mireia; Zamora-Ros, Raul; Sun, Kai; Cherubini, Antonio; Bandinelli, Stefania; Andres-Lacueva, Cristina

    2015-01-01

    Importance Resveratrol, a polyphenol found in grapes, red wine, chocolate, and certain berries and roots, is considered to have antioxidant, anti-inflammatory, and anti-cancer effects in humans and is related to longevity in some lower organisms. Objective To determine whether resveratrol levels achieved with diet are associated with inflammation, cancer, cardiovascular disease, and mortality in humans. Design Prospective cohort study, the Invecchiare in Chianti (InCHIANTI) Study (“Aging in the Chianti Region”), 1998-2009. Setting Two villages in the Chianti area, Tuscany region of Italy. Participants Population-based sample of 783 community-dwelling men and women, ≥65 y Exposure 24-h urinary resveratrol metabolites Main outcomes and measures Primary outcome measure was all-cause mortality. Secondary outcomes were markers of inflammation (serum C-reactive protein [CRP], interleukin [IL]-6, IL-1β, and tumor necrosis factor [TNF]-α), and prevalent and incident cancer and cardiovascular disease Results Mean (95% Confidence Interval) log total urinary resveratrol metabolite concentrations were 7.08 (6.69, 7.48) nmol/g creatinine. During nine years of follow-up, 268 (34.3%) of the participants died. From the lowest to the highest quartile of baseline total urinary resveratrol metabolites, the proportion of participants who died from all causes was 34.4, 31.6, 33.5, and 37.4%, respectively (P = 0.67). Participants in the lowest quartile had a hazards ratio for mortality of 0.80 (95% confidence interval 0.54, 1.17) when compared with those in the highest quartile of total urinary resveratrol in a multivariable Cox proportional hazards model that adjusted for potential confounders. Resveratrol levels were not significantly associated with serum CRP, IL-6, IL-1β, TNF-α, prevalent or incident cardiovascular disease or cancer. Conclusions: In older community-dwelling adults, total urinary resveratrol metabolite concentration was not associated with inflammatory

  10. Exerpts from the history of alpha recoils.

    PubMed

    Samuelsson, Christer

    2011-05-01

    Any confined air volume holding radon ((222)Rn) gas bears a memory of past radon concentrations due to (210)Pb (T(1/2) = 22 y) and its progenies entrapped in all solid objects in the volume. The efforts of quantifying past radon exposures by means of the left-behind long-lived radon progenies started in 1987 with this author's unsuccessful trials of removing (214)Po from radon exposed glass objects. In this contribution the history and different techniques of assessing radon exposure to man in retrospect will be overviewed. The main focus will be on the implantation of alpha recoils into glass surfaces, but also potential traps in radon dwellings will be discussed. It is concluded that for a successful retrospective application, three crucial imperatives must be met, i.e. firstly, the object must persistently store a certain fraction of the created (210)Pb atoms, secondly, be resistant over decades towards disturbances from the outside and thirdly, all (210)Pb atoms analysed must originate from airborne radon only. For large-scale radon epidemiological studies, non-destructive and inexpensive measurement techniques are essential. Large-scale studies cannot be based on objects rarely found in dwellings or not available for measurements. PMID:21306801

  11. Predicting physical stability in pressurized metered dose inhalers via dwell and instantaneous force colloidal probe microscopy.

    PubMed

    D'Sa, Dexter; Chan, Hak-Kim; Chrzanowski, Wojciech

    2014-09-01

    Colloidal probe microscopy (CPM) is a quantitative predictive tool, which can offer insight into particle behavior in suspension pressurized metered dose inhalers (pMDIs). Although CPM instantaneous force measurements, which involve immediate retraction of the probe upon sample contact, can provide information on inter-particle attractive forces, they lack the ability to appropriately imitate all critical particle pMDI interactions (e.g., particle re-dispersion after prolonged pMDI storage). In this paper, two novel dwell force techniques - indentation and deflection dwell - were employed to mimic long-term particle interactions present in pMDIs, using particles of various internal structures and a model liquid propellant (2H,3H perfluoropentane) as a model system. Dwell measurements involve particle contact for an extended period of time. In deflection dwell mode the probe is held at a specific position, while in indentation dwell mode the probe is forced into the sample with a constant force for the entirety of the contact time. To evaluate the applicability of CPM to predict actual pMDI physical stability, inter-particle force measurements were compared with qualitative and quantitative bulk pMDI measurement techniques (visual quality and light scattering). Measured instantaneous attractive (snap-in) and adhesive (max-pull) forces decreased as a function of increasing surface area, while adhesive forces measured by indentation dwell decreased as a function of dwell contact time for particles containing voids. Instantaneous force measurements provided information on the likelihood of floccule formation, which was predictive of partitioning rates, while indentation dwell force measurements were predictive of formulation re-dispersibility after prolonged storage. Dwell force measurements provide additional information on particle behavior within a pMDI not obtainable via instantaneous measurements. PMID:25058596

  12. Dwell time modulation restrictions do not necessarily improve treatment plan quality for prostate HDR brachytherapy

    NASA Astrophysics Data System (ADS)

    Balvert, Marleen; Gorissen, Bram L.; den Hertog, Dick; Hoffmann, Aswin L.

    2015-01-01

    Inverse planning algorithms for dwell time optimisation in interstitial high-dose-rate (HDR) brachytherapy may produce solutions with large dwell time variations within catheters, which may result in undesirable selective high-dose subvolumes. Extending the dwell time optimisation model with a dwell time modulation restriction (DTMR) that limits dwell time differences between neighboring dwell positions has been suggested to eliminate this problem. DTMRs may additionally reduce the sensitivity for uncertainties in dwell positions that inevitably result from catheter reconstruction errors and afterloader source positioning inaccuracies. This study quantifies the reduction of high-dose subvolumes and the robustness against these uncertainties by applying a DTMR to template-based prostate HDR brachytherapy implants. Three different DTMRs were consecutively applied to a linear dose-based penalty model (LD) and a dose-volume based model (LDV), both obtained from literature. The models were solved with DTMR levels ranging from no restriction to uniform dwell times within catheters in discrete steps. Uncertainties were simulated on clinical cases using in-house developed software, and dose-volume metrics were calculated in each simulation. For the assessment of high-dose subvolumes, the dose homogeneity index (DHI) and the contiguous dose volume histogram were analysed. Robustness was measured by the improvement of the lowest D90% of the planning target volume (PTV) observed in the simulations. For (LD), a DTMR yields an increase in DHI of approximately 30% and reduces the size of the largest high-dose volume by 2-5 cc. However, this comes at a cost of a reduction in D90% of the PTV of 10%, which often implies that it drops below the desired minimum of 100%. For (LDV), none of the DTMRs were able to improve high-dose volume measures. DTMRs were not capable of improving robustness of PTV D90% against uncertainty in dwell positions for both models.

  13. Experimental characterization of the dwell periods in an 8-bars lineage

    NASA Astrophysics Data System (ADS)

    Zobel, Pierluigi B.; Pisoni, Attilio C.

    1994-09-01

    An 8-bars linkage, formed by two four-bars and one slider-crank mechanisms connected in series, designed to obtain a rectilinear motion of the output link with two dwell periods, has been tested to validate the desired output motion. The input crank is powered, using a belt transmission, by an asynchronous motor fed by a voltage source inverter. The displacement in the dwells, measured with a Laser Doppler Vibrometer, has been recorded for different values of the input crank speed. By comparison to theoretical results it is shown that, for high input crank speed, link elasticity and joint clearances strongly influence the displacement amplitude in the dwells.

  14. Forest clearing and sex ratio in forest-dwelling wood ant Formica aquilonia

    NASA Astrophysics Data System (ADS)

    Sorvari, Jouni; Hakkarainen, Harri

    2007-05-01

    Sex ratios of ants have been shown to vary with food resource levels in several studies, but it is not known whether forest clear-cutting has any effect on sex ratio of aphid-tending forest-dwelling ants. We investigated whether the offspring sex ratio of the forest dwelling ant Formica aquilonia varied as a response to clear-cutting. We found that the proportion of males was smaller in clear-cuts than in adjacent forests. Our results are among the first showing that anthropogenic changes in forest structures may have a potential to modify sex ratios of social insects and other forest-dwelling animals.

  15. Documentation of Advance Care Planning for Community-Dwelling Elders

    PubMed Central

    Yung, Victoria Y.; Walling, Anne M.; Min, Lillian; Wenger, Neil S.

    2010-01-01

    Abstract Background Advance planning for end-of-life care has gained acceptance, but actual end-of-life care is often incongruent with patients' previously stated goals. We assessed the flow of advance care planning information from patients to medical records in a community sample of older adults to better understand why advance care planning is not more successful. Methods Our study used structured interview and medical record data from community-dwelling older patients in two previous studies: Assessing Care of Vulnerable Elders (ACOVE)-1 (245 patients age ≥65 years and screened for high risk of death/functional decline in 1998–1999) and ACOVE-2 (566 patients age ≥75 who screened positive for falls/mobility disorders, incontinence, and/or dementia in 2002–2003). We compared interview data on patients' preferences, advance directives, and surrogate decision-makers with findings from the medical record. Results In ACOVE-1, 38% of surveyed patients had thought about limiting the aggressiveness of medical care; 24% of surveyed patients stated that they had spoken to their doctor about this. The vast majority of patients (88%–93%) preferred to die rather than remain permanently in a coma, on a ventilator, or tube fed. Regardless of patients' specific preferences, 15%–22% of patients had preference information in their medical record. Among patients who reported that they had completed an advance directive and had given it to their health-care provider, 15% (ACOVE-1) and 47% (ACOVE-2) had advance directive information in the medical record. Among patients who had not completed an advance directive but had given surrogate decision-maker information to their provider, 0% (ACOVE-1) and 16% (ACOVE-2) had documentation of a surrogate decision-maker in the medical record. Conclusions Community-dwelling elders' preferences for end-of-life care are not consistent with documentation in their medical records. Electronic health records and standardized data

  16. Uranium and thorium series radionuclides in drinking water from drilled bedrock wells: correlation to geology and bedrock radioactivity and dose estimation.

    PubMed

    Isam Salih, M M; Pettersson, H B L; Lund, E

    2002-01-01

    Natural radioactivity in drinking water from 328 drilled wells was studied in correlation to source parameters. Poor correlation to both aquifer geology and bedrock radioactivity was observed. Concentrations of 238U, 226Ra, 228Ra, 222Rn and 210Po in groundwater samples was in the ranges <0.027-5.3, <0.016-4.9, <0.014-1.24, 5-8105 and <0.05-0.947 Bq.l(-1) respectively. In about 80% of the sites the radon concentration exceeds the Nordic recommended exemption level for radon in drinking water and 15% of the sites exceed the action limit. The effective doses from ingestion were calculated and presented in association with geology. Doses due to ingestion ranged between 0.05 and 20.4 mSv.y(-1), where the average contribution from 222Rn amounted to 75%. In comparison, the effective doses from inhalation of indoor 222Rn ranged between 0.2 and 20 mSv.y(-1). The average contribution from inhalation of 222Rn in air to the total effective dose (ingestion+inhalation) was 58 +/- 22%, 73 +/- 18% and 77 +/- 16% (1 SD) for the age categories 1 y, 10 y and adults respectively. PMID:12430963

  17. ASSOCIATIONS BETWEEN GENETIC DIVERSITY AND ANTHROPOGENIC DISTURBANCE IN MIDWESTERN STREAM-DWELLING MINNOWS

    EPA Science Inventory

    Anthropogenic disturbances may leave imprints on patterns of intraspecific genetic diversity through their effects on population size, adaptation, migration, and mutation. We examined patterns of genetic diversity for a stream-dwelling minnow (the central stoneroller, Campostoma...

  18. A theoretical justification of the sine with dwell manoeuvre

    NASA Astrophysics Data System (ADS)

    Bruzelius, Fredrik

    2015-04-01

    The sine with dwell (SWD) manoeuvre has received much attention within the context of vehicle stability testing. This manoeuvre is used in a test developed by the NHTSA, designed to certificate electronic stability control systems in light vehicles. The test is used in legislations as well as in consumer tests all over the globe. The SWD manoeuvre was designed using test vehicles on a test track and experimentally validated. The paper at hand uses optimal control theory to theoretically justify the use of the SWD manoeuvre to produce a severe lateral motion and over-steering based on steering input. It is shown that a manoeuvre similar to the SWD manoeuvre can be obtained from an optimal control problem using simple vehicle dynamics models. The optimal control method is further used to analyse the manoeuvre's robustness with respect to vehicle dimensions and tyre properties. It is shown that the manoeuvre is robust in dimensions, which theoretically motivates its application for various sizes of vehicles.

  19. Planning for Serious Illness amongst Community-Dwelling Older Adults

    PubMed Central

    2013-01-01

    Older adults have long been encouraged to maintain their autonomy by expressing their wishes for health care before they become too ill to meaningfully participate in decision making. This study explored the manner in which community-dwelling adults aged 55 and older plan for serious illness. An online survey was conducted within the province of Saskatchewan, Canada, with 283 adults ranging in age from 55 to 88 years. Planning for future medical care was important for the majority (78.4%) of respondents, although only 25.4% possessed a written advance care plan and 41.5% had designated a substitute decision maker. Sixty percent of respondents reported conversations about their treatment wishes; nearly half had discussed unacceptable states of health. Associations between key predictor variables and planning behaviors (discussions about treatment wishes or unacceptable states of health; designation of a substitute decision maker; preparation of a written advance care plan) were assessed using binary logistic regression. After controlling for all predictor variables, self-reported knowledge about advance care planning was the key variable significantly associated with all four planning behaviors. The efforts of nurses to educate older adults regarding the process of advance care planning can play an important role in enhancing autonomy. PMID:23691299

  20. Racial Differences in Anticholinergic Use among Community-Dwelling Elders

    PubMed Central

    Felton, Maria; Hanlon, Joseph T.; Perera, Subashan; Thorpe, Joshua M.; Marcum, Zachary A.

    2014-01-01

    Objective Few studies have examined racial differences in potentially inappropriate medication use. The objective of this study was to examine racial disparities in using prescription and/or non-prescription anticholinergics, a type of potentially inappropriate medication, over time. Design Longitudinal. Setting Health, Aging, and Body Composition Study (years 1, 5, and 10) Participants Three thousand fifty-five black and white community-dwelling older adults at year one Main Outcome Measure Highly anticholinergic medication use as per the 2012 American Geriatrics Society Beers Criteria. Results Blacks represented 41.4% of the participants at year 1. At year 1, 13.4% of blacks used an anticholinergic medication compared to 17.8% of whites, and this difference persisted over the ensuing ten-year period. Diphenhydramine was the most common anticholinergic medication reported at baseline and year 5 and meclizine at year 10 for both races. Controlling for demographics, health status and access to care factors, blacks were 24-45% less likely to use any anticholinergics compared to whites over the years considered (all p<0.05). Conclusion The use of prescription and/or non-prescription anticholinergic medications was less common in older blacks than whites over a ten-year period, and the difference was unexplained by demographics, health status and access-to-care. PMID:25893702

  1. Distributed interactive communication in simulated space-dwelling groups.

    PubMed

    Brady, Joseph V; Hienz, Robert D; Hursh, Steven R; Ragusa, Leonard C; Rouse, Charles O; Gasior, Eric D

    2004-03-01

    This report describes the development and preliminary application of an experimental test bed for modeling human behavior in the context of a computer generated environment to analyze the effects of variations in communication modalities, incentives and stressful conditions. In addition to detailing the methodological development of a simulated task environment that provides for electronic monitoring and recording of individual and group behavior, the initial substantive findings from an experimental analysis of distributed interactive communication in simulated space dwelling groups are described. Crews of three members each (male and female) participated in simulated "planetary missions" based upon a synthetic scenario task that required identification, collection, and analysis of geologic specimens with a range of grade values. The results of these preliminary studies showed clearly that cooperative and productive interactions were maintained between individually isolated and distributed individuals communicating and problem-solving effectively in a computer-generated "planetary" environment over extended time intervals without benefit of one another's physical presence. Studies on communication channel constraints confirmed the functional interchangeability between available modalities with the highest degree of interchangeability occurring between Audio and Text modes of communication. The effects of task-related incentives were determined by the conditions under which they were available with Positive Incentives effectively attenuating decrements in performance under stressful time pressure. PMID:14983895

  2. A Factorial Data Rate and Dwell Time Experiment in the National Transonic Facility

    NASA Technical Reports Server (NTRS)

    DeLoach, R.

    2000-01-01

    This report is an introductory tutorial on the application of formal experiment design methods to wind tunnel testing, for the benefit of aeronautical engineers with little formal experiment design training. It also describes the results of a Study to determine whether increases in the sample rate and dwell time of the National Transonic Facility data system Would result in significant changes in force and moment data. Increases in sample rate from 10 samples per second to 50 samples per second were examined, as were changes in dwell time from one second per data point to two seconds. These changes were examined for a representative aircraft model in a range of tunnel operating conditions defined by angles of attack from 0 deg to 3.8 degrees, total pressure from 15.0 psi to 24.1 psi, and Mach numbers from 0.52 to 0.82. No statistically significant effect was associated with the change in sample rate. The change in dwell time from one second to two seconds affected axial force measurements, and to a lesser degree normal force measurements. This dwell effect comprises a "rectification error" caused by incomplete cancellation of the positive and negative elements of certain low frequency dynamic components that are not rejected by the one-Hz low-pass filters of the data system. These low frequency effects may be due to tunnel circuit phenomena and other sources. The magnitude of the dwell effect depends on dynamic pressure, with angle of attack and Mach number influencing the strength of this dependence. An analysis is presented which suggests that the magnitude of the rectification error depends on the ratio of measurement dwell time to the period of the low-frequency dynamics, as well as the amplitude of the dynamics The essential conclusion of this analysis is that extending the dwell time (or, equivalently, replicating short-dwell data points) reduces the rectification error.

  3. Constraints for Using Radon-in-Water Concentrations as an Indicator for Groundwater Discharge into Surface Water Bodies

    NASA Astrophysics Data System (ADS)

    Petermann, Eric; Schubert, Michael

    2015-04-01

    The radon (222-Rn) activity concentration of surface water is a favourable indicator for the detection of groundwater discharge into surface water bodies since radon is highly enriched in groundwater relative to surface waters. Hence, positive radon-in-water anomalies are interpreted as groundwater discharge locations. For this approach, usually, radon time-series are recorded along transects in near-surface waters. Time-series of radon-in-water concentration are commonly measured by permanent radon extraction from a water pump stream and continuous monitoring of the resulting radon-in-air concentration by means of a suitable radon detector. Radon-in-water concentrations are derived from the recorded radon-in-air signal by making allowances for water/air partitioning of radon. However, several constraints arise for this approach since undesirable factors are influencing the radon-in-water concentration. Consequently, corrections are required to remove the effect of these undesirable factors from the radon signal. First, an instrument inherent response delay between actual changes in the radon-in-water concentration and the related radon-in-air signal was observed during laboratory experiments. The response delay is due to (i) the water/air transfer kinetics of radon and (ii) the delayed decay equilibrium between radon and its progeny polonium (218-Po), which is actually being measured by most radon-in-air monitors. We developed a physical model, which considers all parameters that are responsible for the response delay. This model allows the reconstruction of radon-in-water time-series based on radon-in-air records. Second, on a time-scale of several hours the tidal stage is known as a major driver for groundwater discharge fluctuations due to varying hydraulic gradients between groundwater and surface water during a tidal cycle. Consequently, radon-in-water time-series that are detected on tidal coasts are not comparable among each other without normalization

  4. Radon exhalation and natural radiation exposure in low ventilated rooms

    NASA Astrophysics Data System (ADS)

    Abdallah, A. M.; Mohery, M.; Yaghmour, Saud J.; Alddin, S. H.

    2012-11-01

    In the first part of this paper, the influence of radon (222Rn) exhalation rate from walls and air exchange upon its concentration in room air was considered using a simple mathematical room model. The exhalation rates have been determined in ten low ventilated rooms of ten villas in Jeddah city (Western Province) of Saudi Arabia. An electroprecipitation method has been applied for the determination of the 222Rn gas concentration in these rooms. The mean 222Rn gas concentration was found to be 46.80±8.80 Bq m-3. The mean 222Rn exhalation rate was estimated to be 20.11±6.90 Bq m-2 h-1. The mean inhalation dose due to the exposure to 222Rn gas was calculated to be 1.18±2.30 mSv y-1. The second part of this paper deals with a study of natural radionuclide contents of samples collected from the building materials of these rooms under investigations in part one. Analyses were performed in Marinelli beakers with a gamma spectroscopy system to quantify radioactivity concentrations. The collected samples revealed the presence of the uranium-radium (226Ra) and thorium (232Th) radioisotopes as well as 40K. The mean activity concentration of 226Ra, 232Th and 40K was determined to be 48.30±5.08, 43.90±5.63 and 223.90±7.55 Bq kg-1, respectively. These activities amount to a radium equivalent (Raeq) of 125.96±15.90 Bq kg-1 and to a mean value of external hazard index (Hex) of 0.34±0.04.

  5. Radon concentration of waters in Greece and Cyprus

    NASA Astrophysics Data System (ADS)

    Nikolopoulos, D.; Vogiannis, E.; Louizi, A.

    2009-04-01

    Radon (222Rn) is a radioactive gas generated by the decay of the naturally occurring 238U series. It is considered very important from radiological point of view, since it is the most significant natural source of human radiation exposure (approximately 50% from all natural sources). Radon is present in soil, rocks, building materials and waters. Through diffusion and convection, radon migrates and emanates to the atmosphere. Outdoors, radon concentrates at low levels (in the order of 10 Bq/m3). However indoors, radon accumulates significantly. It is trivial to observe indoor environments with high radon levels (in the order of 400 Bq/m3 or higher). Radon accumulation indoors, depends on the composition of the underlying soil and rock formation, on building materials, meteorological parameters, ventilation, heating and water use. Although soil and building materials are the most significant radon sources, there have been reported elevated radon concentrations in building structures due to entering water. It is the radon concentrations in the entering water, the volume and the way of water usage, separated or in combination, that result in large amounts of radon in indoor air. Moreover, radon is a factor of stomach radiation burden due to water consumption. This burden is estimated by measurements of radon concentrations in waters. Due to the health impact of radon exposure, the reporting team continuously measures radon. This work focused on the radon concentrations exposure due to water consumption and use in Greece and Cyprus. Various locations in Greece and Cyprus were accessed taking into consideration existing natural radioactivity data (mainly radon in water), however under the restriction of the capability of movement. Radon in water was measured by Alpha Guard (Genitron Ltd) via a special unit (Aqua Kit). This unit consists of a vessel used for forced degassing of radon diluted in water samples, a security vessel used for water drop deposition. Vessels and

  6. Field studies of streamflow generation using natural and injected tracers on Bickford and Walker Branch Watersheds

    SciTech Connect

    Genereux, D.; Hemond, H.; Mulholland, P.

    1992-05-01

    Field studies of streamflow generation were undertaken on two forested watersheds, the West Road subcatchment of Bickford Watershed in central Massachusetts and the West Fork of Walker Branch Watershed in eastern Tennessee. A major component of the research was development of a two-stage methodology for the use of naturally-occurring {sup 222}Rn as a tracer. The first of the two stages was solving a mass-balance equation for {sup 222}Rn around a stream reach of interest in order to calculate Rn{sub q}, the {sup 222}Rn content of the lateral inflow to the reach; a conservative tracer (chloride) and a volatile tracer (propane) were injected into the study stream to account for lateral inflow to, and volatilization from, the study reach. The second stage involved quantitative comparison of Rn{sub q} to the measured {sup 222}Rn concentrations of different subsurface waters in order to assess how important these waters were in contributing lateral inflow to the stream reach.

  7. Concentrator Systems

    NASA Astrophysics Data System (ADS)

    Luque-Heredia, Ignacio; Luque, Antonio

    2015-10-01

    The following sections are included: * Introduction * The early development of CPV * Concentrator solar cells * Optics for photovoltaic concentrators * Photovoltaic concentration modules * Tracking systems for photovoltaic concentration * High-concentration systems * Rating and performance * Cost considerations * Conclusions * References

  8. Measurement of Indoor Radon-222 and Radon-220 Concentrations in Central Japan

    SciTech Connect

    Oka, Mitsuaki; Shimo, Michikuni; Tokonami, Shinji; Sorimachi, Atsuyuki; Takahashi, Hiromichi; Ishikawa, Tetsuo

    2008-08-07

    A passive-type radon/thoron detector was used for measuring indoor radon and thoron concentrations at 90 dwellings in Aichi and Gifu prefectures in central Japan during 90 days from December, 2006 to March, 2007. The radon and thoron concentrations were 21.1 Bq/m3 and 25.1 Bq/m3, respectively. The dose due to radon and thoron in dwellings was roughly evaluated as 0.7 mSv/y and 2.4 mSv/y, respectively. The examination of the geological factor and house condition having an effect on indoor radon concentration was performed.

  9. The Relationship between a Distribution of Submarine Groundwater Discharge and a Local-scale Coastal Geology and Topography in Northern Japan

    NASA Astrophysics Data System (ADS)

    Honda, H.; Sugimoto, R.; Shoji, J.; Tominaga, O.; Kobayashi, S.; Taniguchi, M.

    2014-12-01

    Submarine groundwater discharge (SGD) has been recognized as an important pathway for material transport to the marine environment. Submarine fresh groundwater discharge will occur wherever an aquifer is hydraulically connected with the sea and the water table is above sea level. The driving force behind this process is the hydraulic gradient from the upland region of a watershed to the surface water discharge location at the coast. Permeability also affects the rate of recharge into an aquifer and discharge into a sea. In the present study, we thus evaluated the SGD impact on the two locations in eastern (Yuza) and western (Otsuchi) side of the northern Japan to clarify the relationship between the coastal distribution of SGD and the local-scale coastal geology and topography. We applied 222Rn monitoring survey with the dual-loop system (Dimova et al. 2009) to assess the local-scale impact of SGD. In the Yuza area, abundant spring discharges are present around the coast at the terminus of volcanic lava flows. We conducted the continuous 222Rn monitoring at boat speeds of < 2 knots along the coast for a few kilometers scale assessment. Moreover, at the two contrastive specific sites (Kamaiso beach and Shonai dune) where are different properties of geology and topography, the continuous 222Rn monitoring using a rubber boat at speeds of 1 m per 20 seconds was done for a few hundred meters scale assessment. As a result, 222Rn activity clearly showed the higher impact of SGD on the Kamaiso beach compared to the Shonai dune. In the Otsuchi area, on the other hand, 222Rn monitoring survey was also done at boat speeds of < 2 knots in Otsuchi Bay and Funakoshi Bay in same tidal conditions (2 hours before lowest tide), because there are negligible influence of tidal changes on 222Rn concentrations in the Pacific coast of Japan. 222Rn concentrations in Otsuchi Bay were significantly higher than those in Funakoshi Bay. Although the Otsuchi Bay and Funakoshi Bay is adjacent

  10. Urinary iodine and stable isotope analysis to examine habitat influences on thyroid hormones among coastal dwelling American alligators.

    PubMed

    Boggs, Ashley S P; Hamlin, Heather J; Nifong, James C; Kassim, Brittany L; Lowers, Russell H; Galligan, Thomas M; Long, Stephen E; Guillette, Louis J

    2016-01-15

    The American alligator, generally a freshwater species, is known to forage in marine environments despite the lack of a salt secreting gland found in other crocodylids. Estuarine and marine foraging could lead to increased dietary uptake of iodine, a nutrient necessary for the production of thyroid hormones. To explore the influence of dietary iodine on thyroid hormone health of coastal dwelling alligators, we described the seasonal plasma thyroxine and triiodothyronine concentrations measured by radioimmunoassay and urinary iodine (UI) concentrations measured by inductively coupled plasma mass spectrometry. We also analyzed long-term dietary patterns through stable isotope analysis of scute tissue. Snout-to-vent length (SVL) was a significant factor among UI and stable isotope analyses. Large adult males greater than 135cm SVL had the highest UI concentrations but did not display seasonality of thyroid hormones. Alligators under 135 SVL exhibited seasonality in thyroid hormones and a positive relationship between UI and triiodothyronine concentrations. Isotopic signatures provided supporting evidence that large males predominantly feed on marine/estuarine prey whereas females showed reliance on freshwater/terrestrial prey supplemented by marine/estuarine prey. UI measurement provided immediate information that correlated to thyroid hormone concentrations whereas stable isotope analysis described long-term dietary patterns. Both techniques demonstrate that adult alligators in coastal environments are utilizing estuarine/marine habitats, which could alter thyroid hormone physiology. PMID:26684734

  11. Effects of mining-derived metals on riffle-dwelling crayfish in southwestern Missouri and southeastern Kansas, USA

    USGS Publications Warehouse

    Allert, Ann L.; DiStefano, Robert J.; Schmitt, Christopher J.; Fairchild, James F.; Brumbaugh, William G.

    2012-01-01

    Riffle-dwelling crayfish populations were sampled at 16 sites in 4 tributaries of the Spring River located within the Tri-State Mining District in southwest Missouri. Crayfish density, physical habitat quality, and water quality were examined at each site to assess the ecological effects of mining-derived metals on crayfish. Metals (lead, zinc, and cadmium) were analyzed in samples of surface water, sediment, detritus, and whole crayfish. Sites were classified a posteriori into reference, mining, and downstream sites primarily based on metal concentrations in the materials analyzed. Three species of crayfish (Orconectes neglectus neglectus, O. macrus, and O. virilis) were collected during the study; however, only O. n. neglectus was collected at all sites. Mean crayfish densities were significantly lower at mining sites than at reference sites. Mean concentrations of metals were significantly correlated among the materials analyzed and were significantly greater at mining and downstream sites than at reference sites. Principal component analyses showed a separation of sites due to an inverse relationship among crayfish density, metals concentrations, and physical habitat quality variables. Sediment probable-effects quotients and surface-water toxic unit scores were significantly correlated; both indicated risk of toxicity to aquatic biota at several sites. Metals concentrations in whole crayfish at several sites exceeded concentrations known to be toxic to carnivorous wildlife. Mining-derived metals have the potential to impair ecosystem function through decreased organic matter processing and nutrient cycling in streams due to decreased crayfish densities.

  12. Estimation of the residential radon levels and the annual effective dose in dwellings of Shiraz, Iran, in 2015

    PubMed Central

    Yarahmadi, Maryam; Shahsavani, Abbas; Mahmoudian, Mohammad Hassan; Shamsedini, Narges; Rastkari, Noushin; Kermani, Majid

    2016-01-01

    Introduction Radon is the second most important cause of lung cancer after smoking. Thus, the determination of indoor radon concentrations in dwellings and workplaces is an important public health concern. The purpose of this research was to measure the concentration of radon gas in residential homes and public places in the city of Shiraz and its relationship with the type and age of the buildings as well as the type of materials used to construct the building (brick, block). We also determined the radon dosages that occupants of the building would receive. Methods The present study is a descriptive-analytical and cross-sectional research that was conducted on the building’s indoor air in the city of Shiraz in 2015. Using geographic information system (GIS) software and a spatial sampling cell with an area of 25 square kilometers, 200 points were selected. In this study, we used passive diffusive samplers as Solid State Nuclear Track Detector (SSNTD) CR-39 polycarbonate films for three months in the winter. Sampling was conducted in accordance with the U.S. Environmental Protection Agency’s protocol. We determined the concentrations of radon gas at the time of sampling, and calibration factors were determined. The data were analyzed by IBM-SPSS, version 20, descriptive statistics, Kruskal-Wallis, and Mann–Whitney tests. Results This study showed that the average radon concentration was 57.6 ± 33.06 Bq/m3 in residential dwellings. The average effective dose was 1.45 mSv/y. The concentration of radon in 5.4% of the houses was found to be greater than 100 Bq/m3, which is above the level allowed by the World Health Organization (WHO). Conclusion Since radon is the second leading cause of lung cancer, it seems necessary to increase the public’s awareness of this issue and to take action to reduce radon in homes when the concentrations are above the WHO’s guideline. PMID:27504164

  13. Effect of Dwell Time on the Mental Health of US Military Personnel With Multiple Combat Tours

    PubMed Central

    Han, Peggy P.; Dougherty, Amber L.; Galarneau, Michael R.

    2012-01-01

    Objective. We investigated the association of the length of time spent at home between deployments, or dwell time, with posttraumatic stress disorder (PTSD) and other mental health disorders. Methods. We included US Marine Corps personnel identified from military deployment records who deployed to Operation Iraqi Freedom once (n = 49 328) or twice (n = 16 376). New-onset mental health diagnoses from military medical databases were included. We calculated the ratio of dwell-to-deployment time (DDR) as the length of time between deployments divided by the length of the first deployment. Results. Marines with 2 deployments had higher rates of PTSD than did those with 1 deployment (2.1% versus 1.2%; P < .001). A DDR representing longer dwell times at home relative to first deployment length was associated with reduced odds of PTSD (odds ratio [OR] = 0.47; 95% confidence interval [CI] = 0.32, 0.70), PTSD with other mental health disorder (OR = 0.56; 95% CI = 0.33, 0.94), and other mental health disorders (OR = 0.62; 95% CI = 0.51, 0.75). Conclusions. Longer dwell times may reduce postdeployment risk of PTSD and other mental health disorders. Future research should focus on the role of dwell time in adverse health outcomes. PMID:22390601

  14. Stochastic kinetics of a single-headed motor protein: Dwell time distribution of KIF1A

    NASA Astrophysics Data System (ADS)

    Garai, Ashok; Chowdhury, Debashish

    2011-03-01

    KIF1A, a processive single-headed kinesin superfamily motor, hydrolyzes adenosine triphosphate (ATP) to move along a filamentous track called microtubule. The stochastic movement of KIF1A on the track is characterized by an alternating sequence of pause and translocation. The sum of the durations of pause and the following translocation defines the dwell time. Using the NOSC model (Nishinari K. et al., Phys. Rev. Lett., 95 (2005) 118101) of individual KIF1A, we systematically derive an analytical expression for the dwell time distribution. More detailed information is contained in the probability densities of the "conditional dwell times"τ±± in between two consecutive steps each of which could be forward (+) or backward (-). We calculate the probability densities Ξ±± of these four conditional dwell times. However, for the convenience of comparison with experimental data, we also present the two distributions Ξ±* of the times of dwell before a forward (+) and a backward (-) step. In principle, our theoretical prediction can be tested by carrying out single-molecule experiments with adequate spatio-temporal resolution.

  15. Increased Concentrations of Short-Lived Decay-Series Radionuclides in Groundwaters Underneath the Nopal I Uranium Deposit at Pena Blanca, Mexico

    NASA Astrophysics Data System (ADS)

    Luo, S.; Ku, T.; Todd, V.; Murrell, M. T.; Dinsmoor, J. C.

    2007-05-01

    The Nopal I uranium ore deposit at Pena Blanca, Mexico, located at > 200 meters above the groundwater table, provides an ideal natural analog for quantifying the effectiveness of geological barrier for isolation of radioactive waste nuclides from reaching the human environments through ground water transport. To fulfill such natural analog studies, three wells (PB1, PB2, and PB3 respectively) were drilled at the site from the land surface down to the saturated groundwater zone and ground waters were collected from each of these wells through large- volume sampling/in-situ Mn-filter filtration for analyses of short-lived uranium/thorium-series radionuclides. Our measurements from PB1 show that the groundwater standing in the hole has much lower 222Rn activity than the freshly pumped groundwater. From this change in 222Rn activity, we estimate the residence time of groundwater in PB1 to be about 20 days. Our measurements also show that the activities of short-lived radioisotopes of Th (234Th), Ra (228Ra, 224Ra, 223Ra), Rn (222Rn), Pb (210Pb), and Po (210Po) in PB1, PB2, and PB3 are all significantly higher than those from the other wells near the Nopal I site. These high activities provide evidence for the enrichment of long-lived U and Ra isotopes in the groundwater as well as in the associated adsorbed phases on the fractured aquifer rocks underneath the ore deposit. Such enrichment suggests a rapid dissolution of U and Ra isotopes from the uranium ore deposit in the vadose zone and the subsequent migration to the groundwater underneath. A reactive transport model can be established to characterize the in-situ transport of radionuclides at the site. The observed change of 222Rn activity at PB1 also suggests that the measured high radioactivityies in ground waters from the site isare not an artifact of drilling operations. However, further studies are needed to assess if or to what extent the radionuclide migration is affected by the previous mining activities at

  16. Natural radioactivity in surface soil samples from dwelling areas in Tehran city, Iran.

    PubMed

    Asgharizadeh, F; Ghannadi, M; Samani, A B; Meftahi, M; Shalibayk, M; Sahafipour, S A; Gooya, E S

    2013-09-01

    The study was carried out to determine radioactivity concentrations in surface soil samples of the city of Tehran and associated potential radiological hazards. The natural radionuclide ((226)Ra, (232)Th and (40)K) contents were determined for 50 locations throughout the geological surface formations in a representative area in the city of Tehran, Iran, using high-resolution gamma-spectrometric analysis. The range of activity concentrations of (226)Ra, (232)Th and (40)K in the soil from the studied areas varies from 30.5±0.6 to 45.4±0.9, 27.3±0.5 to 57.1±1.1 and 328.0±4.6 to 768.5±13.4 Bq kg(-1) with overall mean values of 38.8±0.7, 43.4±0.8 and 555.1±8.9 Bq kg(-1), respectively. The mean radium equivalent activity, external hazard index, internal hazard index to quantify the internal exposure to radon and its daughter products, as well as the gamma activity concentration index for each sample are 143.6±4.6 Bq kg(-1), 0.39, 0.49 and 0.53, respectively. The average estimated radium equivalent is comparable with reported values for many countries in the world. Therefore, these areas may not pose radiological risks to the inhabitants due to harmful effects of the ionising radiation from the natural radioactivity in soil. The calculated average external and internal hazard indexes were found to be less than unity, as a recommended safe level. Estimates of the measured radionuclide content have been made for calculating the absorbed dose rate in the outdoor air at 1 m above the ground level. The absorbed dose rates resulting from those concentrations ranged from 48.1 to 88.7 nGy h(-1). Assuming a 20 % occupancy factor proposed by UNSCEAR, 2000, the corresponding effective dose rates in outdoor air equivalent to the population were calculated to be between 0.06 and 0.11 mSv y(-1). The measurement results and calculated values obtained from this study indicate that the dwelling areas in Tehran city, Iran, have background radioactivity levels within natural

  17. The carbon and oxygen isotope records of reef-dwelling foraminifers subjected to five varied pCO2 seawater

    NASA Astrophysics Data System (ADS)

    Hikami, M.; Ishimura, T.; Suzuki, A.; Nojiri, Y.; Kawahata, H.

    2013-12-01

    Ocean acidification (OA) in response to rising atmospheric pCO2 is generally expected to reduce rates of calcification by reef calcifying organisms, with potentially severe implications for coral reef ecosystems. Reef dwelling foraminifera is one of the most important primary and carbonate producers in coral reef environments. Their shells are composed of high-Mg calcite and they are host to algal endosymbionts. In our previous culture experiment with two algal reef dwelling foraminifers, Amphisorus kudakajimensis and Calcarina gaudichaudii in the seawater of five different pCO2 conditions, net calcification of A. kudakajimensis was reduced under higher pCO2, whereas net calcification of C. gaudichaudii showed continued increasing trend with pCO2. These contrasting responses between the two species are possibly due to differences in calcification mechanisms and to links between calcification by the foraminifers and photosynthesis by the algal endosymbionts. But the factors affecting these calcification mechanisms are poorly understood. In this study, to get a better understanding of the effect of OA on their calcification, we cultured three reef dwelling foraminifers: Amphisorus hemprichii, belong to imperforate species, Baculogypsina sphaerulata, and C. gaudichaudii belong to perforate species, in the seawater of five different pCO2 conditions and we address the response of carbon and oxygen isotopes of the carbonate shells of foraminifers. The oxygen isotope ratio of cultured foraminiferal tests under five varied pCO2 seawater indicated no significant correlation to pCO2 values. On the other hand, the carbon isotope ratio of foraminiferal tests indicated heavy trend with rising pCO2 in all species. Alteration of carbonate chemistry result from ocean acidification may be effect strongly on carbon isotope composition relate to metabolic system (i.e. photosynthesis and respiration). In perforate species, both of oxygen and carbon isotope ratio were lighter than that

  18. The Longitudinal Association of Cumulative Lead Dose with Cognitive Function in Community-dwelling Older Adults

    PubMed Central

    Bandeen-Roche, Karen; Glass, Thomas A.; Bolla, Karen I.; Todd, Andrew C.; Schwartz, Brian S.

    2012-01-01

    Background To evaluate whether cumulative lead dose from environmental exposures is associated with cognitive function and decline, and whether persistent, reversible, or progressive effects are indicated. Methods We used longitudinal linear modeling to evaluate associations of tibia lead concentration with cognitive function and decline in socio-demographically diverse, community-dwelling adults, aged 50-70 years, randomly selected from neighborhoods in Baltimore. Six summary measures of cognitive function were created from standard tests in these domains: language, processing speed, eye-hand coordination, executive functioning, verbal memory and learning, and visual memory. Results The mean (SD) tibia lead level was 18.8 (11.6) μg/g. In models adjusting for demographic characteristics, socioeconomic status (SES), and race/ethnicity, higher tibia lead was associated with a progressive decline in eye-hand coordination in all subjects; stratified analysis substantiated this association only in African-Americans. In all subjects, tibia lead was associated with persistent effects with worse cognitive function in all six domains, but these associations weakened after increasing covariate control. In fully adjusted stratified analysis, persistent effects were present in whites in eye-hand coordination, executive functioning, and verbal memory and learning. Conclusions The study presents the strongest adult evidence to date in a diverse population of the impacts of cumulative lead dose on cognitive function independent of SES. As the study population was relatively young and the average total duration of follow-up short (< 30 months), the findings may represent the lower bound of what the impact of cumulative lead dose might be on the cognitive function of older Americans. PMID:19752734

  19. Grey matter correlates of susceptibility to scams in community-dwelling older adults.

    PubMed

    Duke Han, S; Boyle, Patricia A; Yu, Lei; Arfanakis, Konstantinos; James, Bryan D; Fleischman, Debra A; Bennett, David A

    2016-06-01

    Susceptibility to scams is a significant issue among older adults, even among those with intact cognition. Age-related changes in brain macrostructure may be associated with susceptibility to scams; however, this has yet to be explored. Based on previous work implicating frontal and temporal lobe functioning as important in decision making, we tested the hypothesis that susceptibility to scams is associated with smaller grey matter volume in frontal and temporal lobe regions in a large community-dwelling cohort of non-demented older adults. Participants (N = 327, mean age = 81.55, mean education = 15.30, 78.9 % female) completed a self-report measure used to assess susceptibility to scams and an MRI brain scan. Results indicated an inverse association between overall grey matter and susceptibility to scams in models adjusted for age, education, and sex; and in models further adjusted for cognitive function. No significant associations were observed for white matter, cerebrospinal fluid, or total brain volume. Models adjusted for age, education, and sex revealed seven clusters showing smaller grey matter in the right parahippocampal/hippocampal/fusiform, left middle temporal, left orbitofrontal, right ventromedial prefrontal, right middle temporal, right precuneus, and right dorsolateral prefrontal regions. In models further adjusted for cognitive function, results revealed three significant clusters showing smaller grey matter in the right parahippocampal/hippocampal/fusiform, right hippocampal, and right middle temporal regions. Lower grey matter concentration in specific brain regions may be associated with susceptibility to scams, even after adjusting for cognitive ability. Future research is needed to determine whether grey matter reductions in these regions may be a biomarker for susceptibility to scams in old age. PMID:26100658

  20. Association of genetic variants of CELSR1 and 3q28 with hypertension in community-dwelling individuals.

    PubMed

    Ueyama, Chikara; Horibe, Hideki; Fujimaki, Tetsuo; Oguri, Mitsutoshi; Kato, Kimihiko; Yamada, Yoshiji

    2013-11-01

    Findings of previous studies demonstrated that rs6007897 (C→T, Ala2268Thr) of the cadherin, epidermal growth factor (EGF) laminin A G-type repeats (LAG) seven-pass G-type receptor 1 gene (CELSR1) and rs9846911 (A→G) at chromosome 3q28 were significantly associated with ischemic stroke and chronic kidney disease, respectively. Given that hypertension is a risk factor for both ischemic stroke and chronic kidney disease, it was hypothesized that the association of rs6007897 with ischemic stroke or of rs9846911 with chronic kidney disease might be attributable, at least in part, to their effects on genetic susceptibility to hypertension. The purpose of the present study was to examine a possible association of rs6007897 of CELSR1 or rs9846911 at 3q28 with hypertension in community-dwelling individuals. Study subjects comprised 5,959 community-dwelling individuals (1,670 subjects with hypertension and 4,289 controls) who were recruited to a population-based cohort study. Comparisons of allele frequencies by the Chi-square test revealed that rs6007897 of CELSR1 (P=0.0280) and rs9846911 at 3q28 (P=0.0171) were significantly associated with the prevalence of hypertension. Multivariate logistic regression analysis with adjustment for age, gender, body mass index (BMI), smoking status, the serum concentration of creatinine and the prevalence of dyslipidemia and diabetes mellitus revealed that rs6007897 (P=0.0308; recessive model; odds ratio, 1.56) and rs9846911 (P=0.0353; dominant model; odds ratio, 1.22) were significantly associated with hypertension with the T allele rs6007897 and the G allele rs984691 representing risk factors for this condition. CELSR1 and 3q28 may thus be susceptibility loci for hypertension. PMID:24649039

  1. A Hydrogen-Induced Decohesion Model for Treating Cold Dwell Fatigue in Titanium-Based Alloys

    NASA Astrophysics Data System (ADS)

    Chan, Kwai S.; Moody, Jonathan

    2016-05-01

    Cold dwell fatigue in near-alpha Ti alloys is a time-dependent fracture process at ambient temperature that involves fatigue in the presence of creep to produce cracking on low-energy fracture ( e.g., cleavage) facets in hard alpha grains. In this article, cold dwell fatigue is treated as a hydrogen-induced decohesion process by using a nonlinear cohesive stress-strain relation to describe the decrease in the cohesive strength with increasing local hydrogen contents. It is postulated that during cold dwell fatigue, time-dependent deformation occurs by < a> slip that results in dislocation pileups in soft alpha grains. The stress and dilatational fields of the dislocation pileups assist the transport of internal hydrogen atoms from soft grains to neighboring hard grains. The accumulation of internal hydrogen atoms at the trap sites leads to decohesion along crystallographic planes, which can be slip or hydride habit planes. The decohesion model is applied to treat cold dwell fatigue in Ti-6Al-4V with a basal-transverse texture by modeling the effects of hydrogen-induced decohesion on the stress-fatigue life ( S- N f) response, the time-dependent crack growth response (d a/d t), and the fracture toughness ( K c) as functions of grain orientation. A probabilistic time-dependent fatigue crack growth analysis is then performed to assess the influence of microtexture on the dwell fatigue life of a Ti-6Al-4V ring disk subjected to a long-duration hold at the peak stress of the loading cycle. The results of the probabilistic life computations indicate that dwell fatigue resistance in Ti-6Al-4V may be improved and the risk of disk fracture may be reduced significantly by controlling the microtexture or reducing the size and volume fraction of hard alpha grains in the microstructure.

  2. Socioeconomic and Outdoor Meteorological Determinants of Indoor Temperature and Humidity in New York City Dwellings

    PubMed Central

    Tamerius, JD; Perzanowski, MS; Acosta, LM; Jacobson, JS; Goldstein, IF; Quinn, JW; Rundle, AG; Shaman, J

    2013-01-01

    Background Numerous mechanisms link outdoor weather and climate conditions to human health. It is likely that many health conditions are more directly affected by indoor rather than outdoor conditions. Yet, the relationship between indoor temperature and humidity conditions to outdoor variability, and the heterogeneity of the relationship among different indoor environments are largely unknown. Methods We use 5–14 day measures of indoor temperature and relative humidity from 327 dwellings in New York City for the years 2008–2011 to investigate the relationship between indoor climate, outdoor meteorological conditions, socioeconomic conditions, and building descriptors. Study households were primarily middle-income and located across the boroughs of Brooklyn, Queens, Bronx, and Manhattan. Results Indoor temperatures are positively associated with outdoor temperature during the warm season and study dwellings in higher socioeconomic status neighborhoods are significantly cooler. During the cool season, outdoor temperatures have little effect on indoor temperatures; however, indoor temperatures can range more than 10 °C between dwellings despite similar outdoor temperatures. Apartment buildings tend to be significantly warmer than houses and dwellings on higher floors are also significantly warmer than dwellings on lower floors. Outdoor specific humidity is positively associated with indoor specific and relative humidity, but there is no consistent relationship between outdoor and indoor relative humidity. Conclusions In New York City, the relationship between indoor and outdoor temperature and humidity conditions vary significantly between dwellings. These results can be used to inform studies of health outcomes for which temperature or humidity is an established factor affecting human health and highlights the need for more research on the determinants of indoor climate. PMID:24077420

  3. Nordic Standards for measurement of aircraft noise immission in residential areas and noise reduction of dwellings

    NASA Astrophysics Data System (ADS)

    Svane, Christian; Plovsing, Birger

    Quantification by measurement of aircraft noise in residential areas and air traffic noise reduction of dwellings suffer from sensibility to the measurement technique used. Around the Copenhagen Airport (200.000 opr./year) 3.500 families have been granted from 50% to 90% of sound insulation costs by the Danish Government. Based on experience from evaluation measurements carried out by the Danish Acoustical Institute, the authors have proposed standardized measurement methods for the outdoor aircraft noise in residential areas and for the noise reduction of dwellings. In 1989 both noise measurement methods were accepted as Nordic Standards (NORDTEST ACOU 074 and 075) by Denmark, Finland, Iceland, Norway and Sweden.

  4. 24 CFR 203.16 - Certificate and contract regarding use of dwelling for transient or hotel purposes.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... use of dwelling for transient or hotel purposes. 203.16 Section 203.16 Housing and Urban Development... use of dwelling for transient or hotel purposes. Every application filed with respect to insurance of... housing or any part thereof covered by the mortgage for transient or hotel purposes, together with...

  5. 24 CFR 203.16 - Certificate and contract regarding use of dwelling for transient or hotel purposes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... use of dwelling for transient or hotel purposes. 203.16 Section 203.16 Housing and Urban Development... use of dwelling for transient or hotel purposes. Every application filed with respect to insurance of... housing or any part thereof covered by the mortgage for transient or hotel purposes, together with...

  6. 24 CFR 203.16 - Certificate and contract regarding use of dwelling for transient or hotel purposes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... use of dwelling for transient or hotel purposes. 203.16 Section 203.16 Housing and Urban Development... use of dwelling for transient or hotel purposes. Every application filed with respect to insurance of... housing or any part thereof covered by the mortgage for transient or hotel purposes, together with...

  7. 24 CFR 203.16 - Certificate and contract regarding use of dwelling for transient or hotel purposes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... use of dwelling for transient or hotel purposes. 203.16 Section 203.16 Housing and Urban Development... use of dwelling for transient or hotel purposes. Every application filed with respect to insurance of... housing or any part thereof covered by the mortgage for transient or hotel purposes, together with...

  8. 24 CFR 203.16 - Certificate and contract regarding use of dwelling for transient or hotel purposes.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... use of dwelling for transient or hotel purposes. 203.16 Section 203.16 Housing and Urban Development... use of dwelling for transient or hotel purposes. Every application filed with respect to insurance of... housing or any part thereof covered by the mortgage for transient or hotel purposes, together with...

  9. Systematic Literature Review of Randomized Control Trials Assessing the Effectiveness of Nutrition Interventions in Community-Dwelling Older Adults

    ERIC Educational Resources Information Center

    Bandayrel, Kristofer; Wong, Sharon

    2011-01-01

    Objective: Nutrition interventions may play an important role in maintaining the health and quality of life in community-dwelling older adults. To the authors' knowledge, no systematic literature review has been conducted on the effectiveness of nutrition interventions in the community-dwelling older adult population. Design: Systematic literature…

  10. 24 CFR 206.131 - Contract rights and obligations for mortgages on individual dwelling units in a condominium.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES HOME EQUITY CONVERSION... construed to include the individual dwelling unit and the undivided interest in the common areas and... individual dwelling unit to the Secretary, the mortgagee shall certify: (1) To any changes in the plan...

  11. Correlation between environmental relative moldiness index (ERMI) values in French dwellings and other measures of fungal contamination

    EPA Science Inventory

    The Environmental Relative Moldiness Index (ERMI) is a DNA-based metric developed to describe the fungal contamination in US dwellings. Our goal was to determine if the ERMI values in dwellings in north western France were correlated with other measures of fungal contamination. D...

  12. 7 CFR Exhibit A to Subpart A of... - Estimated Breakdown of Dwelling Costs for Estimating Partial Payments

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 12 2010-01-01 2010-01-01 false Estimated Breakdown of Dwelling Costs for Estimating Partial Payments A Exhibit A to Subpart A of Part 1924 Agriculture Regulations of the Department of... A of Part 1924—Estimated Breakdown of Dwelling Costs for Estimating Partial Payments With slab...

  13. Radiological risk from thoron, a case study: The particularly radon-prone area of Bolsena, and the lesson learned

    NASA Astrophysics Data System (ADS)

    Cinelli, G.; Capaccioni, B.; Hernández-Ceballos, M. A.; Mostacci, D.; Perghem, A.; Tositti, L.

    2015-11-01

    The contribution of 220Rn is usually negligible compared to that of 222Rn: its very short half-life makes escape from its source site within the rock very unlikely and it never has time enough to filtrate through the ground and through cracks in the floors or cellar walls to reach living quarters. This however becomes untrue if walls built with 232Th-rich materials are present: then sizeable amounts of thoron may be detected in the closed areas bounded by those walls. This is the case for many dwellings in central Italy, and the town of Bolsena (northern Latium) is presented as a case study. A typical building of the area, entirely constructed with tuff blocks, is investigated and the annual dose rates calculated for varying distances from the wall. Thoron concentration was found to decrease with a relaxation length of 13 cm. Thoron was found to pose a significant risk. The rate of air exchange was found to produce little effect. Wall plastering acts as a filter: thoron diffuses through it but a HVL of less than 1 cm was found to prevail.

  14. Mobile Dwelling Unit Developed by a Group of Mechanical Engineering Design Students

    ERIC Educational Resources Information Center

    Novak, Marina; Pozun, Matjaz; Dolsak, Bojan; Pocivavsek, Tadej

    2004-01-01

    The increasing number of homeless people is one of the most burning problems of nowadays world. Society has to find the way to fight against it and provide help to those people that have no place to stay. For short-term interventions, the application of the mobile dwelling units seems to be the only possible solution. However, existing mobile…

  15. 24 CFR 200.926 - Minimum property standards for one and two family dwellings.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 2 2012-04-01 2012-04-01 false Minimum property standards for one and two family dwellings. 200.926 Section 200.926 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR...

  16. Factors that affect the quality of life of community-dwelling elderly women with musculoskeletal disorders

    PubMed Central

    Takemasa, Seiichi; Nakagoshi, Ryoma; Uesugi, Masayuki; Inoue, Yuri; Gotou, Makoto; Koeda, Hideki; Naruse, Susumu

    2015-01-01

    [Purpose] This study aimed to examine the quality of life (QOL) of community-dwelling elderly women with musculoskeletal disorders and factors that affect it. [Subjects] The subjects were 27 community-dwelling elderly women with musculoskeletal disorders (mean age: 76.3 ± 7.4 years). Their physical and psychological conditions, QOL, and other characteristics were researched. [Methods] The Japanese version of Life-Space Assessment was used to assess the subjects’ daily life activities; the Japanese version of Fall Efficacy Scale (FES), to assess their fear of falling; the Geriatric Depression Scale (GDS 15), to assess their depression status; and the Life Satisfaction Index K (LSIK), to assess their QOL. [Results] The results indicated that the number of family members living together, degree of pain, fear of falling, and depression affect the LSIK scores of the community-dwelling elderly women with musculoskeletal disorders. [Conclusion] The study results suggest that the LSIK scores of community-dwelling elderly women with musculoskeletal disorders can be improved by easing their pain, improving their physical abilities to prevent falls, and improving their mobility. The results also suggest that continuing rehabilitation treatment is required. PMID:26696713

  17. Pesticides in Urban Multiunit Dwellings: Hazard IdentificationUsing Classification and Regression Tree (CART) Analysis

    EPA Science Inventory

    Many units in public housing or other low-income urban dwellings may have elevated pesticide residues, given recurring infestation, but it would be logistically and economically infeasible to sample a large number of units to identify highly exposed households to design interven...

  18. Self-Reported versus Professionally Assessed Functional Limitations in Community-Dwelling Very Old Individuals

    ERIC Educational Resources Information Center

    Carlsson, Gunilla; Haak, Maria; Nygren, Carita; Iwarsson, Susanne

    2012-01-01

    The objective of this study was to examine the relationship between self-reported and professionally assessed functional limitations in community-dwelling very old individuals. In total, 306 single-living adults aged 81-90 years were included in this cross-sectional study. The main outcome measure was the presence and absence of self-reported and…

  19. 24 CFR 200.926 - Minimum property standards for one and two family dwellings.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false Minimum property standards for one... Minimum Property Standards § 200.926 Minimum property standards for one and two family dwellings. (a... units in a structure where the units are located side-by-side in town house fashion. Section...

  20. 24 CFR 200.926 - Minimum property standards for one and two family dwellings.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 2 2013-04-01 2013-04-01 false Minimum property standards for one... Minimum Property Standards § 200.926 Minimum property standards for one and two family dwellings. (a... units in a structure where the units are located side-by-side in town house fashion. Section...

  1. Dwell in Possibility: PLAR and e-Portfolios in the Age of Information and Communication Technologies

    ERIC Educational Resources Information Center

    Brown, Judith O.

    2011-01-01

    Emily Dickinson wrote, "I dwell in Possibility--A fairer House than Prose--More Numerous of Windows--Superior--for Doors" (p. 657). Dickinson's simple yet profound reference to the expansive nature of poetry over prose may be taken as a metaphor for the possibilities of information and communication technologies (ICTs) over written modes of…

  2. Inferior vena cava filter removal after prolonged dwell time of 2310 days

    PubMed Central

    Lichliter, Andrew; Cura, Marco

    2016-01-01

    Inferior vena cava filters are commonly placed for a variety of indications, often when anticoagulation is contraindicated. Although technical success is high and complication rates low, there are complications that are important to be aware of. We present the case of a 29-year-old woman with a prolonged filter dwell time resulting in complications. PMID:27365875

  3. 24 CFR 100.80 - Discriminatory representations on the availability of dwellings.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... shall be unlawful, because of race, color, religion, sex, handicap, familial status, or national origin... rented, because of race, color, religion, sex, handicap, familial status, or national origin. (2... rental of dwellings because of race, color, religion, sex, handicap, familial status, or national...

  4. 24 CFR 100.80 - Discriminatory representations on the availability of dwellings.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... shall be unlawful, because of race, color, religion, sex, handicap, familial status, or national origin... rented, because of race, color, religion, sex, handicap, familial status, or national origin. (2... rental of dwellings because of race, color, religion, sex, handicap, familial status, or national...

  5. 24 CFR 100.80 - Discriminatory representations on the availability of dwellings.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... shall be unlawful, because of race, color, religion, sex, handicap, familial status, or national origin... rented, because of race, color, religion, sex, handicap, familial status, or national origin. (2... rental of dwellings because of race, color, religion, sex, handicap, familial status, or national...

  6. 24 CFR 100.80 - Discriminatory representations on the availability of dwellings.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... shall be unlawful, because of race, color, religion, sex, handicap, familial status, or national origin... rented, because of race, color, religion, sex, handicap, familial status, or national origin. (2... rental of dwellings because of race, color, religion, sex, handicap, familial status, or national...

  7. Test-retest reliability of the safe driving behavior measure for community-dwelling elderly drivers

    PubMed Central

    Song, Chiang-Soon; Lee, Joo-Hyun; Han, Sang-Woo

    2016-01-01

    [Purpose] The Safe Driving Behavior Measure (SDBM) is a self-report measurement tools that assesses the safe-driving behaviors of the elderly. The purpose of this study was to evaluate the test-retest reliability of the SDBM among community-dwelling elderly drivers. [Subjects and Methods] A total of sixty-one community-dwelling elderly were enrolled to investigate the reliability of the SDBM. The SDBM was assessed in two sessions that were conducted three days apart in a quiet and well-organized assessment room. That test-retest reliability of overall scores and three domain scores of the SDBM were statistically evaluated using intraclass correlation coefficients [ICC (2.1)]. Pearson correlation coefficients were used to quantify bivariate associations among the three domains of the SDBM. [Results] The SDBM demonstrated excellent rest-retest reliability for community-dwelling elderly drivers. The Cronbach alpha coefficients of the three domains of person-vehicle (0.979), person-environment (0.944), and person-vehicle-environment (0.971) of the SDBM indicate high internal consistency. [Conclusion] The results of this study suggest that the SDBM is a reliable measure for evaluating the safe- driving of automobiles by community-dwelling elderly, and is adequate for detecting changes in scores in clinical settings. PMID:27390401

  8. Test-retest reliability of the safe driving behavior measure for community-dwelling elderly drivers.

    PubMed

    Song, Chiang-Soon; Lee, Joo-Hyun; Han, Sang-Woo

    2016-06-01

    [Purpose] The Safe Driving Behavior Measure (SDBM) is a self-report measurement tools that assesses the safe-driving behaviors of the elderly. The purpose of this study was to evaluate the test-retest reliability of the SDBM among community-dwelling elderly drivers. [Subjects and Methods] A total of sixty-one community-dwelling elderly were enrolled to investigate the reliability of the SDBM. The SDBM was assessed in two sessions that were conducted three days apart in a quiet and well-organized assessment room. That test-retest reliability of overall scores and three domain scores of the SDBM were statistically evaluated using intraclass correlation coefficients [ICC (2.1)]. Pearson correlation coefficients were used to quantify bivariate associations among the three domains of the SDBM. [Results] The SDBM demonstrated excellent rest-retest reliability for community-dwelling elderly drivers. The Cronbach alpha coefficients of the three domains of person-vehicle (0.979), person-environment (0.944), and person-vehicle-environment (0.971) of the SDBM indicate high internal consistency. [Conclusion] The results of this study suggest that the SDBM is a reliable measure for evaluating the safe- driving of automobiles by community-dwelling elderly, and is adequate for detecting changes in scores in clinical settings. PMID:27390401

  9. On rate-dependent polycrystal deformation: the temperature sensitivity of cold dwell fatigue

    PubMed Central

    Zhang, Zhen; Cuddihy, M. A.; Dunne, F. P. E.

    2015-01-01

    A temperature and rate-dependent crystal plasticity framework has been used to examine the temperature sensitivity of stress relaxation, creep and load shedding in model Ti-6Al polycrystal behaviour under dwell fatigue conditions. A temperature close to 120°C is found to lead to the strongest stress redistribution and load shedding, resulting from the coupling between crystallographic slip rate and slip system dislocation hardening. For temperatures in excess of about 230°C, grain-level load shedding from soft to hard grains diminishes because of the more rapid stress relaxation, leading ultimately to the diminution of the load shedding and hence, it is argued, the elimination of the dwell debit. Under conditions of cyclic stress dwell, at temperatures between 20°C and 230°C for which load shedding occurs, the rate-dependent accumulation of local slip by ratcheting is shown to lead to the progressive cycle-by-cycle redistribution of stress from soft to hard grains. This phenomenon is termed cyclic load shedding since it also depends on the material's creep response, but develops over and above the well-known dwell load shedding, thus providing an additional rationale for the incubation of facet nucleation. PMID:26528078

  10. Characteristics of Walking, Activity, Fear of Falling and Falls in Community Dwelling Older Adults by Residence

    PubMed Central

    Wert, David M.; Talkowski, Jaime B.; Brach, Jennifer; VanSwearingen, Jessie

    2016-01-01

    Objectives Research focusing on community dwelling older adults includes adults living in senior living residences (SLR) and independent community residences (ICR). Walking, physical activity, fear and falls may differ based on residence. Purpose We describe characteristics of walking, physical activity, fear of falling and fall history between community dwelling older adults by residence. Methods Participants of this secondary analysis included community dwelling older adults from independent living units within a senior life care community (SLR) and older adults recruited from the Pittsburgh community (ICR). Demographic information, physical (gait speed and physical activity), psychosocial (fear of falling and confidence in walking) and fall history measures were collected. Results Adults living in SLR compared to ICR were older, more likely to live alone and had greater disease burden. Compared to ICR, individuals in SLR reported less fear of falling (SAFFE fear .24 and .50 respectively). Fewer older adults in SLR compared to ICR reported falling in the past year. Discussion Older adults living in SLR compared to ICR had similar physical function but differed in report of fear of falling and fall history. Recognizing the possible differences in psychosocial function by place of residence is important for healthcare providers and researchers conducting interventions and studies for community-dwelling older adults. PMID:20503733

  11. 1. Mill village dwelling at 817 Forest St. in LaGrange. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Mill village dwelling at 817 Forest St. in LaGrange. Note the hipped roof and wrap-around porch with heavy cornice and Doric columns. The quality of decorative detail here suggests that this house would have been for a mill manager. - 817 Forest Street (House), 817 Forest Street, La Grange, Troup County, GA

  12. Distractor Dwelling, Skipping, and Revisiting Determine Target Absent Performance in Difficult Visual Search.

    PubMed

    Horstmann, Gernot; Herwig, Arvid; Becker, Stefanie I

    2016-01-01

    Some targets in visual search are more difficult to find than others. In particular, a target that is similar to the distractors is more difficult to find than a target that is dissimilar to the distractors. Efficiency differences between easy and difficult searches are manifest not only in target-present trials but also in target-absent trials. In fact, even physically identical displays are searched through with different efficiency depending on the searched-for target. Here, we monitored eye movements in search for a target similar to the distractors (difficult search) versus a target dissimilar to the distractors (easy search). We aimed to examine three hypotheses concerning the causes of differential search efficiencies in target-absent trials: (a) distractor dwelling (b) distractor skipping, and (c) distractor revisiting. Reaction times increased with target similarity which is consistent with existing theories and replicates earlier results. Eye movement data indicated guidance in target trials, even though search was very slow. Dwelling, skipping, and revisiting contributed to low search efficiency in difficult search, with dwelling being the strongest factor. It is argued that differences in dwell time account for a large amount of total search time differences. PMID:27574510

  13. Efficient sampling of ground-dwelling arthropods using pitfall traps in arid steppes.

    PubMed

    Cheli, Germán H; Corley, Juan C

    2010-01-01

    Pitfall trapping is probably the most frequently used method for sampling ground-dwelling arthropods. While the capture of specimens in pitfall traps largely depends on the number of individuals in the sampled area, trap design and trapping effort for a given environment, can also affect sampling success. The aim of this study was to determine the best pitfall trapping design for collecting ground-dwelling arthropods in the wind-blown and cold arid steppe areas of Patagonia. We tested four designs of traps, six types of preservative and different times of activation as well as the quantity of traps. Both preservation attributes and sampling efficiency differed between different trap designs and fluids compared. We conclude that in order to obtain reliable data on the structure of a community of ground-dwelling arthropods in Patagonia, at least three pitfall traps per experimental unit are required. In addition, traps should be opened for a minimum of 10 days filled with 300 ml of 30% ethylene glycol. We also suggested the use of a simple trap design (i. e. without funnel or roof). We believe these findings will contribute to more appropriate sampling of the ground dwelling fauna of Patagonia as well as other arid areas, leading to more reliable diversity studies. PMID:21271057

  14. Rural-Urban Differences in Preventable Hospitalizations among Community-Dwelling Veterans with Dementia

    ERIC Educational Resources Information Center

    Thorpe, Joshua M.; Van Houtven, Courtney H.; Sleath, Betsy L.; Thorpe, Carolyn T.

    2010-01-01

    Context: Alzheimer's patients living in rural communities may face significant barriers to effective outpatient medical care. Purpose: We sought to examine rural-urban differences in risk for ambulatory care sensitive hospitalizations (ACSH), an indicator of access to outpatient care, in community-dwelling veterans with dementia. Methods: Medicare…

  15. Discontinuation of Neuroleptics in Community-Dwelling Individuals with Mental Retardation and Mental Illness.

    ERIC Educational Resources Information Center

    Pary, Robert J.

    1995-01-01

    Sixty-eight community-dwelling individuals with mental retardation and mental illness were discontinued from neuroleptics. Those with a psychotic disorder were significantly more likely to be restarted on neuroleptics at 3 months and 12 months. Not having a history of delusions was significantly associated with remaining neuroleptic-free at 3…

  16. Distractor Dwelling, Skipping, and Revisiting Determine Target Absent Performance in Difficult Visual Search

    PubMed Central

    Horstmann, Gernot; Herwig, Arvid; Becker, Stefanie I.

    2016-01-01

    Some targets in visual search are more difficult to find than others. In particular, a target that is similar to the distractors is more difficult to find than a target that is dissimilar to the distractors. Efficiency differences between easy and difficult searches are manifest not only in target-present trials but also in target-absent trials. In fact, even physically identical displays are searched through with different efficiency depending on the searched-for target. Here, we monitored eye movements in search for a target similar to the distractors (difficult search) versus a target dissimilar to the distractors (easy search). We aimed to examine three hypotheses concerning the causes of differential search efficiencies in target-absent trials: (a) distractor dwelling (b) distractor skipping, and (c) distractor revisiting. Reaction times increased with target similarity which is consistent with existing theories and replicates earlier results. Eye movement data indicated guidance in target trials, even though search was very slow. Dwelling, skipping, and revisiting contributed to low search efficiency in difficult search, with dwelling being the strongest factor. It is argued that differences in dwell time account for a large amount of total search time differences. PMID:27574510

  17. Hospitalization Rates of Nursing Home Residents and Community-Dwelling Seniors in British Columbia

    ERIC Educational Resources Information Center

    Ronald, Lisa A.; McGregor, Margaret J.; McGrail, Kimberlyn M.; Tate, Robert B.; Broemling, Anne-Marie

    2008-01-01

    The overall use of acute care services by nursing home (NH) residents in Canada has not been well documented. Our objectives were to identify the major causes of hospitalization among NH facility residents and to compare rates to those of community-dwelling seniors. A retrospective cohort was defined using population-level health administrative…

  18. Wheelchair Use among Community-Dwelling Older Adults: Prevalence and Risk Factors in a National Sample

    ERIC Educational Resources Information Center

    Clarke, Philippa; Colantonio, Angela

    2005-01-01

    Older adults are the largest group of wheelchair users yet there are no peer-reviewed studies on the national profile of older wheelchair users in Canada. We investigated the characteristics of wheelchair users in a national sample of community-dwelling older adults from the Canadian Study of Health and Aging (CSHA-2). Questions on the use of…

  19. Future Discounting by Slum-Dwelling Youth versus University Students in Rio de Janeiro

    ERIC Educational Resources Information Center

    Ramos, Dandara; Victor, Tania; Seidl-de-Moura, Maria Lucia; Daly, Martin

    2013-01-01

    We compared Future Discounting (FD, preference for smaller, sooner rewards over larger, later ones) by 160 Brazilian youth (16-30 years old; 71 women and 89 men). University students and slum-dwelling (favela) youth were compared. Participants completed a monetary FD task, a scale of youngsters' view of their neighborhood, and self-reported…

  20. EFFECTS OF ON-BOTTOM OYSTER MARICULTURE ON SMALL, SEDIMENT-DWELLING INVERTEBRATES

    EPA Science Inventory

    As part of a programmatic effort to determine estuarine habitat values for ecological risk assessments, quantitative field studies of small ( 0.5 mm), sediment-dwelling invertebrates were conducted in Willapa Bay, WA in July 1998 and Tillamook Bay, OR in July 1999. The six habit...

  1. OYSTER GROUNDS, A SUPERIOR HABITAT FOR SMALL, SEDIMENT-DWELLING INVERTEBRATES

    EPA Science Inventory

    As part of a programmatic effort to determine estuarine habitat values for ecological risk assessments, quantitative field studies of small, sediment-dwelling invertebrates were conducted in Willapa Bay, WA in July 1998 and Tillamook Bay, OR in July 1999. The six habitats includ...

  2. 24 CFR 42.375 - One-for-one replacement of lower-income dwelling units.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 1 2012-04-01 2012-04-01 false One-for-one replacement of lower-income dwelling units. 42.375 Section 42.375 Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development DISPLACEMENT, RELOCATION ASSISTANCE, AND REAL...

  3. 24 CFR 42.375 - One-for-one replacement of lower-income dwelling units.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 1 2014-04-01 2014-04-01 false One-for-one replacement of lower-income dwelling units. 42.375 Section 42.375 Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development DISPLACEMENT, RELOCATION ASSISTANCE, AND REAL...

  4. 49 CFR 24.204 - Availability of comparable replacement dwelling before displacement.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... before displacement. 24.204 Section 24.204 Transportation Office of the Secretary of Transportation... displacement. (a) General. No person to be displaced shall be required to move from his or her dwelling unless... requires immediate vacation of the real property, such as when continued occupancy of the...

  5. 49 CFR 24.204 - Availability of comparable replacement dwelling before displacement.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... before displacement. 24.204 Section 24.204 Transportation Office of the Secretary of Transportation... displacement. (a) General. No person to be displaced shall be required to move from his or her dwelling unless... requires immediate vacation of the real property, such as when continued occupancy of the...

  6. 49 CFR 24.204 - Availability of comparable replacement dwelling before displacement.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... before displacement. 24.204 Section 24.204 Transportation Office of the Secretary of Transportation... displacement. (a) General. No person to be displaced shall be required to move from his or her dwelling unless... requires immediate vacation of the real property, such as when continued occupancy of the...

  7. 24 CFR 42.375 - One-for-one replacement of lower-income dwelling units.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 1 2011-04-01 2011-04-01 false One-for-one replacement of lower-income dwelling units. 42.375 Section 42.375 Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development DISPLACEMENT, RELOCATION ASSISTANCE, AND REAL...

  8. 49 CFR 24.204 - Availability of comparable replacement dwelling before displacement.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... before displacement. 24.204 Section 24.204 Transportation Office of the Secretary of Transportation... displacement. (a) General. No person to be displaced shall be required to move from his or her dwelling unless... requires immediate vacation of the real property, such as when continued occupancy of the...

  9. 24 CFR 42.375 - One-for-one replacement of lower-income dwelling units.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 1 2013-04-01 2013-04-01 false One-for-one replacement of lower-income dwelling units. 42.375 Section 42.375 Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development DISPLACEMENT, RELOCATION ASSISTANCE, AND REAL...

  10. 49 CFR 24.204 - Availability of comparable replacement dwelling before displacement.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... before displacement. 24.204 Section 24.204 Transportation Office of the Secretary of Transportation... displacement. (a) General. No person to be displaced shall be required to move from his or her dwelling unless... requires immediate vacation of the real property, such as when continued occupancy of the...

  11. Native Dwellings of North America, Grades 3 to 6. Teacher's Kit.

    ERIC Educational Resources Information Center

    Shemie, Bonnie; Branston, Linda; Main, Lorna

    This teacher's resource kit is designed to complement the six books in the "Native Dwellings" series and to provide suggestions for a comprehensive curriculum unit. The books describe the shelters created by a pre-20th century groups of Native American peoples. The relationship of weather, geography, and culture is examined and identified as a…

  12. The Effects of a 12-Week Walking Program on Community-Dwelling Older Adults

    ERIC Educational Resources Information Center

    Cheng, Shun-Ping; Tsai, Tzu-I; Lii, Yun-Kung; Yu, Shu; Chou, Chen-Liang; Chen, I-Ju

    2009-01-01

    Walking is a popular and easily accessible form of physical activity. However, walking instruction for older adults is based on the evidence gathered from younger populations. This study evaluated walking conditions, strength, balance, and subjective health status after a 12-week walking-training program in community-dwelling adults greater than…

  13. Nutritional Status and Risk Factors for Chronic Disease in Urban-Dwelling Adults with Down Syndrome

    ERIC Educational Resources Information Center

    Braunschweig, Carol L.; Gomez, Sandra; Sheean, Patricia; Tomey, Kristin M.; Rimmer, James; Heller, Tamar

    2004-01-01

    Nutritional status and biochemical risk factors for chronic disease were assessed in 48 community-dwelling adults with Down syndrome in the Chicago area. Dietary intake was measured using a food frequency questionnaire completed by the participant's primary caregiver; anthropometric measures included height and weight and waist circumference.…

  14. 24 CFR 100.80 - Discriminatory representations on the availability of dwellings.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... shall be unlawful, because of race, color, religion, sex, handicap, familial status, or national origin... rented, because of race, color, religion, sex, handicap, familial status, or national origin. (2... rental of dwellings because of race, color, religion, sex, handicap, familial status, or national...

  15. 7 CFR 1924.262 - Handling complaints involving dwellings constructed by the self-help method.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... the self-help method. 1924.262 Section 1924.262 Agriculture Regulations of the Department of... constructed by the self-help method. When a borrower whose dwelling was constructed by the self-help method... the guidance of the self-help group. Defects which are determined to be the responsibility of...

  16. 7 CFR 1924.262 - Handling complaints involving dwellings constructed by the self-help method.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... by the self-help method. 1924.262 Section 1924.262 Agriculture Regulations of the Department of... constructed by the self-help method. When a borrower whose dwelling was constructed by the self-help method... the guidance of the self-help group. Defects which are determined to be the responsibility of...

  17. 7 CFR 1924.262 - Handling complaints involving dwellings constructed by the self-help method.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... by the self-help method. 1924.262 Section 1924.262 Agriculture Regulations of the Department of... constructed by the self-help method. When a borrower whose dwelling was constructed by the self-help method... the guidance of the self-help group. Defects which are determined to be the responsibility of...

  18. 7 CFR 1924.262 - Handling complaints involving dwellings constructed by the self-help method.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... by the self-help method. 1924.262 Section 1924.262 Agriculture Regulations of the Department of... constructed by the self-help method. When a borrower whose dwelling was constructed by the self-help method... the guidance of the self-help group. Defects which are determined to be the responsibility of...

  19. Dwelling on the Earth: Heidegger and Working in the Out-of-Doors.

    ERIC Educational Resources Information Center

    Wohlgemut, Matthew

    2000-01-01

    Heidegger's analyses of human being-in-the-world deconstructs our current "technological" outlook on the world as something to be used and suggests an alternative concept of dwelling in a place. Outdoor educators seeking to foster an environmental ethic must create a space where participants can "listen," become attuned to the world, and consider…

  20. 24 CFR 203.437 - Mortgages involving a dwelling unit in a cooperative housing development.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...-FEDERAL HOUSING COMMISSIONER, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER AUTHORITIES SINGLE FAMILY MORTGAGE INSURANCE Contract Rights... right of permanent possession of the dwelling unit. (e) In lieu of the types of title evidence...

  1. Characteristics of carbonyls: Concentrations and source strengths for indoor and outdoor residential microenvironments in China

    NASA Astrophysics Data System (ADS)

    Wang, B.; Lee, S. C.; Ho, K. F.

    Indoor and outdoor carbonyl concentrations were measured simultaneously in 12 urban dwellings in Beijing, Shanghai, Guangzhou, and Xi'an, China in summer (from July to September in 2004) and winter (from December 2004 to February 2005). Formaldehyde was the most abundant indoor carbonyls species, while formaldehyde, acetaldehyde and acetone were found to be the most abundant outdoor carbonyls species. The average formaldehyde concentrations in summer indoor air varied widely between cities, ranging from a low of 19.3 μg m -3 in Xi'an to a high of 92.8 μg m -3 in Beijing. The results showed that the dwellings with tobacco smoke, incense burning or poor ventilation had significantly higher indoor concentrations of certain carbonyls. It was noticed that although one half of the dwellings in this study installed with low emission building materials or furniture, the carbonyls levels were still significantly high. It was also noted that in winter both the indoor and outdoor acetone concentrations in two dwellings in Guangzhou were significantly high, which were mainly caused by the usage of acetone as industrial solvent in many paint manufacturing and other industries located around Guangzhou and relatively longer lifetime of acetone for removal by photolysis and OH reaction than other carbonyls species. The indoor carbonyls levels in Chinese dwellings were higher than that in dwellings in the other countries. The levels of indoor and ambient carbonyls showed great seasonal differences. Six carbonyls species were carried out the estimation of indoor source strengths. Formaldehyde had the largest indoor source strength, with an average of 5.25 mg h -1 in summer and 1.98 mg h -1 in winter, respectively. However, propionaldehyde, crotonaldehyde and benzaldehyde had the weakest indoor sources.

  2. Association of Day Length and Weather Conditions with Physical Activity Levels in Older Community Dwelling People

    PubMed Central

    Witham, Miles D.; Donnan, Peter T.; Vadiveloo, Thenmalar; Sniehotta, Falko F.; Crombie, Iain K.; Feng, Zhiqiang; McMurdo, Marion E. T.

    2014-01-01

    Background Weather is a potentially important determinant of physical activity. Little work has been done examining the relationship between weather and physical activity, and potential modifiers of any relationship in older people. We therefore examined the relationship between weather and physical activity in a cohort of older community-dwelling people. Methods We analysed prospectively collected cross-sectional activity data from community-dwelling people aged 65 and over in the Physical Activity Cohort Scotland. We correlated seven day triaxial accelerometry data with daily weather data (temperature, day length, sunshine, snow, rain), and a series of potential effect modifiers were tested in mixed models: environmental variables (urban vs rural dwelling, percentage of green space), psychological variables (anxiety, depression, perceived behavioural control), social variables (number of close contacts) and health status measured using the SF-36 questionnaire. Results 547 participants, mean age 78.5 years, were included in this analysis. Higher minimum daily temperature and longer day length were associated with higher activity levels; these associations remained robust to adjustment for other significant associates of activity: age, perceived behavioural control, number of social contacts and physical function. Of the potential effect modifier variables, only urban vs rural dwelling and the SF-36 measure of social functioning enhanced the association between day length and activity; no variable modified the association between minimum temperature and activity. Conclusions In older community dwelling people, minimum temperature and day length were associated with objectively measured activity. There was little evidence for moderation of these associations through potentially modifiable health, environmental, social or psychological variables. PMID:24497925

  3. Exposure to radon in dwellings in the Sharri community, Kosovo.

    PubMed

    Bahtijari, M; Vaupotic, J; Gregoric, A; Stegnar, P; Kobal, I

    2008-01-01

    Indoor air radon concentration was measured by exposing etched track detectors in the sleeping and living rooms of 18 houses in 6 villages of the Sharri community in Kosovo. Values ranged from 24 to 209 Bq m(-3), with only one exceeding 200 Bq m(-3), with a geometric mean and geometric standard deviation of 95.4 Bq m(-3) and 1.6, respectively. On the basis of the assumption that the spring radon concentrations obtained in this survey represent the yearly average, annual effective doses of residents were calculated; they range from 0.89 to 4.7 mSv y(-1), with the geometric mean and geometric standard deviation of 1.5 mSv y(-1) and 2.2, respectively. No mitigation measures are planned to be undertaken. PMID:18083721

  4. Evaluating the Impact of Dwell Time on Solder Interconnect Durability Under Bending Loads

    NASA Astrophysics Data System (ADS)

    Menon, Sandeep; Osterman, Michael; Pecht, Michael

    2015-11-01

    With the increasing portability and miniaturization of modern-day electronics, the mechanical robustness of these systems has become more of a concern. Existing standards for conducting mechanical durability tests of electronic assemblies include bend, shock/drop, vibration, and torsion. Although these standards provide insights into both cyclic fatigue and overstress damage incurred in solder interconnects (widely regarded as the primary mode of failure in electronic assemblies), they fail to address the impact of time- dependent (creep) behavior due to sustained mechanical loads on solder interconnect durability. It has been seen in previous studies that solder durability under thermal cycling loads is inversely proportional to the dwell time or hold time at either temperature extreme of the imposed temperature cycle. Fatigue life models, which include dwell time, have been developed for solder interconnects subject to temperature cycling. However, the fatigue life models that have been developed in the literature for solder interconnects under mechanical loads fail to address the influence of the duration of loading. In this study, solder interconnect test vehicles were subjected to cyclic mechanical bending with various dwell times in order to understand the impact of the duration of mechanical loads on solder interconnect durability. The solder interconnects examined in this study were formed with 2512 resistor packages using various solder compositions [tin-lead (Sn-Pb) and 96.5Sn-3Ag-0.5Cu (SAC305)]. To evaluate the impact of dwell time, the boards were tested with 0 s, 60 s, and 300 s of dwell time at both extremes of the loading profile. It was observed that an increase in the dwell time of the loading profile resulted in a decrease in the characteristic life of the solder interconnects. The decrease in fatigue life was attributed to increased creep damage as identified using finite-element simulations. An energy partitioning approach was then used to

  5. An assessment of injury to sediments and sediment-dwelling organisms in the Grand Calumet River and Indiana Harbor Area of Concern, USA

    USGS Publications Warehouse

    MacDonald, D.D.; Ingersoll, C.G.; Smorong, D.E.; Lindskoog, R.A.; Sparks, D.W.; Smith, J.R.; Simon, T.P.; Hanacek, M.A.

    2002-01-01

    This article is the first in a series of three that describe the results of a Natural Resource Damage Assessment (NRDA) conducted in the Grand Calumet River and Indiana Harbor Area of Concern (IHAOC). The assessment area is located in northwest Indiana and was divided into nine reaches to facilitate the assessment. This component of the NRDA was undertaken to determine if sediments and sediment-dwelling organisms have been injured due to exposure to contaminants that have accumulated in sediments as a result of discharges of oil or releases of other hazardous substances from industrial, municipal, and nonpoint sources. To support this assessment, information was compiled on the chemical composition of sediment and pore water; on the toxicity of whole sediments, pore water, and elutriates; and on the status of benthic invertebrate communities. The data on each of these indicators were compared to regionally relevant benchmarks to assess the presence and extent of injury to surface water resources (i.e., sediments) or biological resources (i.e., sediment-dwelling organisms). The results of this assessment indicate that sediment injury has occurred throughout the assessment area, with up to four distinct lines of evidence demonstrating injury within the various reaches. The primary contaminants of concern (i.e., those substances that are present at concentrations that are sufficient to cause or substantially contribute to sediment injury) include metals, polycyclic aromatic hydrocarbons, and total polychlorinated biphenyls.

  6. Radon daughter disequilibria and lead systematics in the western North Atlantic

    NASA Astrophysics Data System (ADS)

    Hussain, N.; Church, T. M.; VéRon, Alain J.; Larson, R. E.

    1998-01-01

    Concentrations of 222Rn and 210Pb were measured in the North Atlantic troposphere in 1989 between April 12 and 28, during the Sulfide Experiment (SEX) Cruise I, and those of 222Rn, 210Pb and 210Po, between October 24 and November 9, during the SEX Cruise II. Concentrations of 210Pb and 210Po were also measured in the rain water, surface seawater, and marine microlayer collected during the SEX Cruise II Other data used and published previously include stable lead and its isotopes [Vèron et al., 1992, 1993] on parallel samples. Low 222Rn contents, of the order of 0.1 and 0.3 Bq m-3, were found in the marine air, while continental air showed nearly 10 times higher concentrations of 222Rn. These results corroborate with the air mass trajectory analyses and continental signatures of stable lead isotopes. Significant correlation is found between 222Rn and 210Pb on the aerosol, indicative of excess continental 222Rn supporting the ingrowth of 210Pb from the atmosphere, in spite of its first-order removal by precipitation. Correlation between 210Pb and stable Pb on the aerosol and in the precipitation document the source of pollutant lead from the continental surface. Mean residence times of marine aerosol based on 210Pb is estimated to be 5.4±1.8 days during the April cruise and 19.7±1.9 days during the October cause. Corresponding deposition velocity for 210Pb is estimated to be 1.9±1.9 cm s-1, a value that suggests the dominant role of precipitation scavenging, or aerosol scavenging by larger host phases such as dust or sea salt. Excess 210Po activities are found on the aerosol relative to what would be expected based on 210Pb and the aerosol residence times. In surface seawaters, deficiencies of 210Po are observed. Mechanisms of 210Po enrichment in atmospheric aerosol may include enrichments from the organic components of marine microlayer, sea-salt aerosol, dust, or air-sea exchange of volatile organo-polonium species.

  7. Radon Measurements at the Molten Salt Reactor Experiment (MSRE) Facility from August 1997 through April 1998

    SciTech Connect

    Coleman, R.L.

    1999-04-01

    From August 1997 through April 1998, radon and radon progeny measurements were collected at the Molten Salt Reactor Experiment (MSRE) facility at Oak Ridge National Laboratory. The purpose of the measurements was to determine the baseline concentrations of 222Rn (radon), 220Rn (thoron), and their progeny in the air at selected points with emphasis on the characterization of 220Rn and its daughter products in the high bay area. The daughter product concentrations ranged from the equivalent of approximately 0.001 times the derived air concentration (DAC) of the isotope mixture up to 0.09 DAC, with the highest measurements occurring inside the pit above the equipment drain tank cell. Direct radon measurements in this area indicated a relatively constant 222Rn concentration with an average value of 1.4 pCi/L and a 220Rn concentration that fluctuated from <1 pCi/L up to about 30 pCi/L. Measurements were also collected inside the vent house adjacent to building 7503. The progeny concentrations inside the room ranged from an equivalent of about 0.002 DAC up to 0.01 DAC. The direct radon measurements in the vent house indicated a relatively constant 222Rn concentration with an average value of 0.7 pCi/L while the 220Rn concentration varied appreciably and ranged from <0.5 pCi/L up to almost 200 pCi/L with an average concentration of 18 pCi/L.

  8. Indoor-outdoor relationships of PM2.5 in four residential dwellings in winter in the Yangtze River Delta, China.

    PubMed

    Wang, Fang; Meng, Dan; Li, Xiuwei; Tan, Junjie

    2016-08-01

    Indoor and outdoor air PM2.5 concentrations in four residential dwellings characterized with different building envelope air tightness levels and HVAC-filter configurations in Yangtze River Delta (YRD) were measured during winter periods in 2014-2015. Steady-state models for indoor PM2.5 were developed for each of the tested dwellings, based on mass balance equation. The indoor air PM2.5 concentrations in the four tested apartments were significantly different. The lowest geometric mean values of indoor air PM2.5 concentrations, I/O ratios, and infiltration factor were observed in D3 with high air tightness and without HVAC-filter system (26.0 μg/m(3), 0.197, and 0.167, respectively), while the highest geometric mean values of indoor air PM2.5 concentrations, I/O ratios, and infiltration factor were observed in D1 (64.9 μg/m(3), 0.876, and 0.867, respectively). For apartment D1 with normal air tightness and without any HVAC-filter system, indoor air PM2.5 concentrations were significantly correlated with outdoor PM2.5 concentrations, especially in severe ambient pollution days, when closed windows can only play a very weak role on the decline of indoor PM2.5 concentrations. With the enhancement of building air tightness, the indoor air PM2.5 concentrations can be decreased effectively and don't vary as much in response to fluctuations in ambient concentrations. For buildings with normal air tightness, the use of HVAC-filter combinations will decrease the indoor PM2.5 significantly. However, for buildings with enhanced air tightness, the only use of fresh makeup air supply system with filter may increase the indoor PM2.5 concentrations. The improvement of filter efficiency for both fresh makeup air and indoor recirculated air are very important. However, purifiers for indoor recirculated air were highly recommended for all buildings. PMID:27213570

  9. Family and Friend Influence on Urban-Dwelling American Indian Adolescent Girl's Sexual Risk Behavior.

    PubMed

    Saftner, Melissa A

    2016-09-01

    Previous research with American Indian (AI) adolescent sexual risk behavior primarily focused on reservation-dwelling youth despite 70% of AIs living off Native lands. Using grounded theory methodology, I sampled 20 adolescent AI girls via talking circles and interviews to explore the perceptions of AI adolescent girls living in an urban, Midwest area about the influence of family and friends on their sexual behavior. Similar to research with other racial groups, participants cited their family and friends as a major influence. Five unique themes emerged related to family and friend influence. Urban-dwelling AI girls rely on their female family members and peers for information related to sex and receive varying messages from their networks of family and friends, which often overlap. AI youth have unique family groups yet have some similarities to other ethnic groups with regard to family and friend relationships that may allow for enhanced intervention development. PMID:26612887

  10. H∞ Adaptive tracking control for switched systems based on an average dwell-time method

    NASA Astrophysics Data System (ADS)

    Wu, Caiyun; Zhao, Jun

    2015-10-01

    This paper investigates the H∞ state tracking model reference adaptive control (MRAC) problem for a class of switched systems using an average dwell-time method. First, a stability criterion is established for a switched reference model. Then, an adaptive controller is designed and the state tracking control problem is converted into the stability analysis. The global practical stability of the error switched system can be guaranteed under a class of switching signals characterised by an average dwell time. Consequently, sufficient conditions for the solvability of the H∞ state tracking MRAC problem are derived. An example of highly manoeuvrable aircraft technology vehicle is given to demonstrate the feasibility and effectiveness of the proposed design method.

  11. The relationships between lifestyle factors and hypertension in community-dwelling Korean adults

    PubMed Central

    Kim, Ill-Gwang; So, Wi-Young; Sung, Dong Jun

    2015-01-01

    [Purpose] This study was performed to determine whether certain lifestyle factors are associated with hypertension in community-dwelling Korean adults. [Subjects and Methods] The subjects were 586 males and 1,135 females > 20 years old who had visited a public health promotion center in Seoul, Republic of Korea to take a survey related to lifestyle factors. Hypertension status was defined according to the criteria of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure VII report. [Results] The relationships between lifestyle factors and hypertension status were assessed using multivariate logistic regression analysis after adjusting for age and gender. Only mental stress and economic status significantly predicted hypertension status. [Conclusion] We conclude that sleep duration, education level, frequency of drinking and smoking status were not associated with hypertension status. However, economic status and mental stress were significantly associated with hypertension in community-dwelling Korean adults, regardless of age or gender. PMID:26834333

  12. Adaptive Output-Feedback Neural Control of Switched Uncertain Nonlinear Systems With Average Dwell Time.

    PubMed

    Long, Lijun; Zhao, Jun

    2015-07-01

    This paper investigates the problem of adaptive neural tracking control via output-feedback for a class of switched uncertain nonlinear systems without the measurements of the system states. The unknown control signals are approximated directly by neural networks. A novel adaptive neural control technique for the problem studied is set up by exploiting the average dwell time method and backstepping. A switched filter and different update laws are designed to reduce the conservativeness caused by adoption of a common observer and a common update law for all subsystems. The proposed controllers of subsystems guarantee that all closed-loop signals remain bounded under a class of switching signals with average dwell time, while the output tracking error converges to a small neighborhood of the origin. As an application of the proposed design method, adaptive output feedback neural tracking controllers for a mass-spring-damper system are constructed. PMID:25122844

  13. The Quality of Pain Treatment in Community-Dwelling Persons with Dementia

    PubMed Central

    Li, Jiwen; Snow, A. Lynn; Wilson, Nancy; Stanley, Melinda A.; Morgan, Robert O.; Sansgiry, Shubhada; Kunik, Mark E.

    2015-01-01

    Background/Aims Despite pervasive and debilitating pain among elders, it is underassessed and undertreated; and cognitive impairment can add challenges. We assessed the quality of pain care for community-dwelling elderly patients with dementia. Methods We phone interviewed 203 Veterans Affairs primary care outpatients with dementia and pain and reviewed medical records to score 15 quality indicators of pain assessment and management. Results Pain assessment was documented for 98%, and a standard pain scale was used for 94%. Modified pain scales were rarely used. Though 70% self-reported pain of ‘quite bad’ or worse, charts documented no pain in 64%. When pain was identified, treatment was offered to 80%; but only 59% had a follow-up assessment within 6 months. Nonpharmacological interventions were underused. Conclusion Community-dwelling elders with dementia are underdiagnosed and undertreated for pain.

  14. The relationships between lifestyle factors and hypertension in community-dwelling Korean adults.

    PubMed

    Kim, Ill-Gwang; So, Wi-Young; Sung, Dong Jun

    2015-12-01

    [Purpose] This study was performed to determine whether certain lifestyle factors are associated with hypertension in community-dwelling Korean adults. [Subjects and Methods] The subjects were 586 males and 1,135 females > 20 years old who had visited a public health promotion center in Seoul, Republic of Korea to take a survey related to lifestyle factors. Hypertension status was defined according to the criteria of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure VII report. [Results] The relationships between lifestyle factors and hypertension status were assessed using multivariate logistic regression analysis after adjusting for age and gender. Only mental stress and economic status significantly predicted hypertension status. [Conclusion] We conclude that sleep duration, education level, frequency of drinking and smoking status were not associated with hypertension status. However, economic status and mental stress were significantly associated with hypertension in community-dwelling Korean adults, regardless of age or gender. PMID:26834333

  15. U.S. population estimates and correlates of sexual abuse of community-dwelling older adults.

    PubMed

    Cannell, Michael B; Manini, Todd; Spence-Almaguer, Emily; Maldonado-Molina, Mildred; Andresen, Elena M

    2014-01-01

    We describe the annual prevalence of sexual abuse among community-dwelling older adults in the United States. We also describe factors associated with experiencing sexual abuse. We used data from 24,343 older adults from the 2005 Behavioral Risk Factor Surveillance System pooled across 18 states. We estimated prevalence of sexual abuse, bivariate distributions, and odds ratio associations across demographic, health, and contextual factors. Our results show that 0.9% of older adults reported experiencing sexual abuse in the previous year. This represents approximately 90,289 community-dwelling older adults. We also report on factors associated with experiencing recent sexual abuse. There was a significant gender by binge drinking interaction, with a stronger association among women. There is a need for health promotion efforts targeted specifically toward older adults, encouraging them to seek services, if possible, after exposure to sexual abuse. PMID:24410194

  16. Rates of depression and participation in senior centre activities in community-dwelling older persons.

    PubMed

    Fulbright, S A

    2010-06-01

    The purpose of this study was to determine the role that senior citizen centres play in decreasing depression in community-dwelling older persons. A quantitative cross-sectional design was utilized. A questionnaire was used to determine demographic and lifestyle data. The dependent variable, depression symptoms, was measured using the 15-point Geriatric Depression Scale. Eighty-eight per cent stated that they attend for the friends and social support. Second, the study demonstrated that community-dwelling older persons can have those needs fulfilled at the senior centres. Ninety-four per cent of them have made close friends at their centres. Ninety-four per cent stated that their lives had improved since attending the senior centre. Eighty-six per cent felt they had made friends on whom they could rely when needed. PMID:20584235

  17. THE RELATIONSHIP BETWEEN SLEEP AND PHYSICAL FUNCTION IN COMMUNITY-DWELLING ADULTS: A PILOT STUDY

    PubMed Central

    Lorenz, Rebecca A.; Budhathoki, Chakra B.; Kalra, Gurpreet K.; Richards, Kathy C.

    2014-01-01

    Over 50% of community-dwelling adults have sleep complaints. Because aging is associated with decline in physical function, coexistent sleep difficulties may exacerbate functional decline. This pilot study explored the relationships between sleep, age, chronic disease burden, and physical function among 50 community-dwelling older adults. Findings revealed significant relationships between total sleep time and preclinical disability (r=−0.33, P≤=0.05) and mobility difficulty (r=−0.36, P≤=0.05). A regression analysis showed that total sleep time was significantly associated with mobility difficulty and preclinical disability, even after controlling for chronic disease burden. These findings suggest that total sleep time may be a catalyst for functional decline. PMID:25167070

  18. Ten years of CO2, CH4, CO and N2O fluxes over Western Europe inferred from atmospheric measurements at Mace Head, Ireland

    NASA Astrophysics Data System (ADS)

    Messager, C.; Schmidt, M.; Ramonet, M.; Bousquet, P.; Simmonds, P.; Manning, A.; Kazan, V.; Spain, G.; Jennings, S. G.; Ciais, P.

    2008-01-01

    We estimated CO2, CH4, CO and N2O emission fluxes over the British Isles and Western Europe using atmospheric radon observations and concentrations recorded at the Mace Head Atmospheric Research Station between 1996 and 2005. We classified hourly concentration data into either long-range European or regional sources from Ireland and UK, by using local wind speed data in conjunction with 222Rn and 212Pb threshold criteria. This leads to the selection of about 7% of the total data for both sectors. We then used continuous 222Rn measurements and assumptions on the surface emissions of 222Rn to deduce the unknown fluxes of CO2, CH4, CO and N2O. Our results have been compared to the UNFCCC, EMEP and EDGAR statistical inventories and to inversion results for CH4. For Western Europe, we found yearly mean fluxes of 4.1±1.5 106 kg CO2 km-2 yr-1 , 11.9±2.0 103 kg CH4 km-2 yr-1, 12.8±4.2 103 kg CO km-2 yr-1 and 520.2±129.2 kg N2O km-2 yr-1, respectively, for CO2, CH4, CO and N2O over the period 1996-2005. The method based upon 222Rn to infer emissions has many sources of systematic errors, in particular its poorly known and variable footprint, uncertainties in 222Rn soil fluxes and in atmospheric mixing of air masses with background air. However, these biases are likely to remain constant in the long-term, which makes the method quite efficient to detect trends in fluxes. Over the last ten years period, the decrease of the anthropogenic CH4, CO and N2O emissions in Europe estimated by inventories (respectively -30%, -35% and -23%) is confirmed by the Mace Head data within 2%. Therefore, the 222Rn method provides an independent way of verification of changes in national emissions derived from inventories. Using European-wide estimates of the CO/CO2 emission ratio, we also found that it is possible to separate the fossil fuel CO2 emissions contribution from the one of total CO2 fluxes. The fossil fuel CO2 emissions and their trends derived in that manner agree very well

  19. Spatial and temporal variability of carbon dioxide and methane fluxes over semi-diurnal and spring-neap-spring timescales in a mangrove creek

    NASA Astrophysics Data System (ADS)

    Call, M.; Maher, D. T.; Santos, I. R.; Ruiz-Halpern, S.; Mangion, P.; Sanders, C. J.; Erler, D. V.; Oakes, J. M.; Rosentreter, J.; Murray, R.; Eyre, B. D.

    2015-02-01

    Automated in situ instrumentation captured high-resolution surface water pCO2, CH4 and 222Rn data at the creek mouth, and ∼500 m upstream in a sub-tropical mangrove ecosystem (Southern Moreton Bay, Australia, S27.78°, E153.38°) over a spring-neap-spring tidal cycle (∼15 days) during November 2013. The partial pressure of CO2 (pCO2) ranged from 385 to 26,106 μatm, CH4 from 1.8 to 889 nM, and 222Rn from 280 to 108,172 dpm m-3. Average surface water pCO2, CH4 and 222Rn were 4-fold higher at the upstream station. Surface water fluxes of CO2 and CH4 ranged from 9.4 to 629.2 mmol CO2 m-2 d-1 and 13.1 to 632.9 μmol CH4 m-2 d-1 depending upon the gas transfer model used and station location. Creek pCO2, CH4 and 222Rn displayed changes over both semi-diurnal and spring-neap-spring tidal scales. Semi-diurnally, all gases had a significant inverse relationship with water depth. Over the spring-neap-spring cycle, all gases exhibited an inverse relationship with tidal amplitude, with higher values during neap tides than spring tides. Estimated fluxes, porewater observations, and the significant positive relationship between surface water pCO2 and CH4, and 222Rn suggests groundwater exchange (i.e., tidal pumping) drives pCO2 and CH4 within the mangrove creek. We hypothesize that a combination of hourly and weekly groundwater-surface water exchange processes drive surface water pCO2 and CH4 in mangrove creeks. Semi-diurnally, flushing of crab burrows leads to high pCO2 and CH4 concentrations at low tide. During the spring-neap-spring cycle, older groundwater enriched in CO2, CH4 and 222Rn seeps into the creek as tidal amplitude decreases, leading to higher concentrations at neap tides.

  20. 12 CFR 1026.36 - Prohibited acts or practices in connection with credit secured by a dwelling.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... “servicing” have the same meanings as provided in 12 CFR 1024.2(b), as amended. (d) Prohibited payments to... consumer credit transaction secured by a dwelling, a loan originator shall not direct or “steer” a...

  1. Malaria endemicity and co-infection with tissue-dwelling parasites in Sub-Saharan Africa: a review.

    PubMed

    Onkoba, Nyamongo W; Chimbari, Moses J; Mukaratirwa, Samson

    2015-01-01

    Mechanisms and outcomes of host-parasite interactions during malaria co-infections with gastrointestinal helminths are reasonably understood. In contrast, very little is known about such mechanisms in cases of malaria co-infections with tissue-dwelling parasites. This is lack of knowledge is exacerbated by misdiagnosis, lack of pathognomonic clinical signs and the chronic nature of tissue-dwelling helminthic infections. A good understanding of the implications of tissue-dwelling parasitic co-infections with malaria will contribute towards the improvement of the control and management of such co-infections in endemic areas. This review summarises and discusses current information available and gaps in research on malaria co-infection with gastro-intestinal helminths and tissue-dwelling parasites with emphasis on helminthic infections, in terms of the effects of migrating larval stages and intra and extracellular localisations of protozoan parasites and helminths in organs, tissues, and vascular and lymphatic circulations. PMID:26377900

  2. Benzodiazepine (BZD) use in community-dwelling older adults: Longitudinal associations with mobility, functioning, and pain.

    PubMed

    Petrov, Megan E; Sawyer, Patricia; Kennedy, Richard; Bradley, Laurence A; Allman, Richard M

    2014-01-01

    The aim of the study was to determine the prospective association between baseline BZD use and mobility, functioning, and pain among urban and rural African-American and non-Hispanic white community-dwelling older adults. From 1999 to 2001, a cohort of 1000 community-dwelling adults, aged ≥ 65 years, representing a random sample of Medicare beneficiaries, stratified by ethnicity, sex, and urban/rural residence were recruited. BZD use was assessed at an in-home visit. Every six months thereafter, study outcomes were assessed via telephone for 8.5-years. Mobility was assessed with the Life-Space Assessment (LSA). Functioning was quantified with level of difficulty in five basic activities of daily living (ADL: bathing, dressing, transferring, toileting, eating), and six instrumental activities of daily living (IADL: shopping, managing money, preparing meals, light and heavy housework, telephone use). Pain was measured by frequency per week and the magnitude of interference with daily tasks. All analytic models were adjusted for relevant covariates and mental health symptoms. After multivariable adjustment, baseline BZD use was significantly associated with greater difficulty with basic ADL (Estimate=0.39, 95% confidence interval (CI): 0.04-0.74), and more frequent pain (Estimate=0.41, 95%CI: 0.09-0.74) in the total sample and declines in mobility among rural residents (Estimate=-0.67, t(5,902)=-1.98, p=0.048), over 8.5 years. BZD use was prospectively associated with greater risk for basic ADL difficulties and frequent pain among African-American and non-Hispanic white community-dwelling older adults, and life-space mobility declines among rural-dwellers, independently of relevant covariates. These findings highlight the potential long-term negative impact of BZD use among community-dwelling older adults. PMID:24880195

  3. Catheter dwell time and diameter affect the recurrence rates after internal urethrotomy

    PubMed Central

    Yürük, Emrah; Yentur, Serhat; Çakır, Ömer Onur; Ertaş, Kasım; Şerefoğlu, Ege Can; Semerciöz, Atilla

    2016-01-01

    Objective Cold-knife direct vision internal urethrotomy (DVIU) is frequently used as the first-line treatment for urethral stricture disease. Although the steps of the procedure are defined in detail, the duration of catheterization and the diameter of the catheter to be used after the operation are not clearly defined. The aim of this study is to evaluate the effects of catheter dwell time and diameter on recurrence rates of urethral stricture disease after DVIU. Material and methods Data of 193 consecutive treatment naïve bulbar urethral stricture patients who underwent DVIU between January 2009 and June 2013 were retrospectively analyzed. Patient demographics and stricture characteristics were noted. Catheter dwell times were grouped as <5 and ≥5 days. The diameters of catheters used were 16, 18 and 22 Fr. The association between recurrence rates, catheter dwell times, and diameter were evaluated with Tukey’s test and Pearson’s correlation test, respectively. Results Overall 193 patients with a mean age of 64.51±12.99 (range: 17 to 85) years were enrolled in the study. Urethral stricture disease recurred in 45 (23.31%) patients within the first year after DVIU. Mean duration of catheterization was 7.47±4.03 and 4.79±1.94 days in patients with and without recurrences, respectively (p=0.0001). Catheter dwell times for ≥5 days were also associated with increased recurrence (p=0.0001). Of the patients with recurrent strictures, 16, 18 and 22Fr catheters were placed in 22.22%, 20% and 57.78% of the patients, respectively. Increased catheter diameter was also associated with higher recurrence rates (p=0.004). Conclusion Shortening the postoperative duration of catheterization and decreasing the catheter size may result in improved recurrence rates after DVIU. Further prospective randomized trials are necessary to confirm these findings.

  4. 24 CFR 42.375 - One-for-one replacement of lower-income dwelling units.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false One-for-one replacement of lower... Development Act of 1974 § 42.375 One-for-one replacement of lower-income dwelling units. (a) Units that must...) In accordance with 42 U.S.C. 5304(d)(3), the one-for-one replacement requirement of this section...

  5. Housing 2020: The future of wood in U.S. dwellings

    SciTech Connect

    Wendt, R.L.

    1994-12-31

    This paper presented at the International Panel and Engineered-Wood Technology Exposition examines the effect that reduced material resources, energy conservation, manufactured dwellings, and construction techniques have had on the use of wood in the housing industry. The topics of the paper include the impact of the energy crisis, financing and affordability crisis, lumber crisis, and a forecast of what the house of the year 2020 will look like, how it will be constructed and of what material will it be constructed.

  6. Levels of phthalate esters in settled house dust from urban dwellings with young children in Nanjing, China

    NASA Astrophysics Data System (ADS)

    Zhang, Qi; Lu, Xiao-Mei; Zhang, Xiao-Ling; Sun, Yong-Gang; Zhu, Dong-Mei; Wang, Bing-Ling; Zhao, Ren-Zheng; Zhang, Zheng-Dong

    2013-04-01

    To investigate the levels and possible determinants of phthalate esters (PEs) in settled house dust from urban dwellings with young children, dust was collected from 215 urban houses in Nanjing, China, and 145 outdoor settled dust samples were collected nearby. Six PEs were measured by gas chromatography/mass spectrometry. All PEs were detected in the dust from approximately 90% of the houses, with the exception of dioctyl phthalate (DOP), which had only a 59% detection rate. Di-2-ethylhexyl phthalate (DEHP) and di-n-butyl phthalate (DBP) were the most abundant PEs, with geometric means of 110 and 16.4 μg g-1, respectively, and maximal concentrations 9950 and 2150 μg g-1. Factor analysis showed that DBP, DEHP and benzyl butyl phthalate (BBP) might come from the same source and were significantly influenced by the use of solid-wood floor wax. High BBP, DEHP, DOP and total PE levels were associated with indices of dampness, and high DOP was associated with humidifier use. In conclusion, six PEs are ubiquitous in urban settled house dust in Nanjing, China, and both plastic materials and cosmetic and personal care products are important sources. Flooring material, dampness and humidifier use potentially influence house dust PE levels.

  7. Validation of N-myristoyltransferase as Potential Chemotherapeutic Target in Mammal-Dwelling Stages of Trypanosoma cruzi

    PubMed Central

    Herrera, Linda J.; Brand, Stephen; Santos, Andres; Nohara, Lilian L.; Harrison, Justin; Norcross, Neil R.; Thompson, Stephen; Smith, Victoria; Lema, Carolina; Varela-Ramirez, Armando; Gilbert, Ian H.; Almeida, Igor C.; Maldonado, Rosa A.

    2016-01-01

    Background Trypanosoma cruzi causes Chagas disease, an endemic and debilitating illness in Latin America. Lately, owing to extensive population movements, this neglected tropical disease has become a global health concern. The two clinically available drugs for the chemotherapy of Chagas disease have rather high toxicity and limited efficacy in the chronic phase of the disease, and may induce parasite resistance. The development of new anti-T. cruzi agents is therefore imperative. The enzyme N-myristoyltransferase (NMT) has recently been biochemically characterized, shown to be essential in Leishmania major, Trypanosoma brucei, and T. cruzi¸ and proposed as promising chemotherapeutic target in these trypanosomatids. Methodology/Principal Findings Here, using high-content imaging we assayed eight known trypanosomatid NMT inhibitors, against mammal-dwelling intracellular amastigote and trypomastigote stages and demonstrated that three of them (compounds 1, 5, and 8) have potent anti-proliferative effect at submicromolar concentrations against T. cruzi, with very low toxicity against human epithelial cells. Moreover, metabolic labeling using myristic acid, azide showed a considerable decrease in the myristoylation of proteins in parasites treated with NMT inhibitors, providing evidence of the on-target activity of the inhibitors. Conclusions/Significance Taken together, our data point out to the potential use of NMT inhibitors as anti-T. cruzi chemotherapy. PMID:27128971

  8. Assessment of inhalation exposure to indoor air pollutants: Screening for health risks of multiple pollutants in Japanese dwellings.

    PubMed

    Azuma, Kenichi; Uchiyama, Iwao; Uchiyama, Shigehisa; Kunugita, Naoki

    2016-02-01

    Over the past few decades, multiple low level indoor pollutants have been found in domestic dwellings. The types and concentrations of these indoor pollutants have not been consistent over time and have changed with alterations in lifestyle, the development of novel products used in housing, and the development of new measurement technologies. To clarify the highest risk pollutants for which health risks should be reduced, we conducted a health risk assessment of 49 indoor air pollutants measured in 602 houses during winter and summer from 2012 to 2014. Inhalation reference concentrations were determined, and the margins of exposure were estimated for each indoor pollutant from measured indoor air concentrations. Health risks due to ammonia and acidic gases, including formic acid, acetic acid, and hydrogen chloride, were also assessed. Overall, during both winter and summer, the highest risk pollutants were acrolein, nitrogen dioxide, benzene, formic acid, and hydrogen chloride. The health risks of propanal, acetaldehyde, and 1,4-dichlorobenzene were also high. Principal component analysis (PCA) suggested an independent principal component for 1,4-dichlorobenzene. The primary source of exposure to 1,4-dichlorobenzene in Japan is an indoor household insect repellent. The improvement of individual lifestyle and housing may be appropriate targets for reducing the risk associated with this compound. The provision of further information on the risk to consumers and promotion of changes in consumer consciousness are needed. PCA suggested that the health risks of indoor air pollutants are amalgamated into similar chemical families, such as aldehydes, aliphatic hydrocarbons, aromatic hydrocarbons, or acetic esters. Our results suggest that health-based guidelines or source control measures, based on these chemical families and similar health endpoints, are appropriate for reducing total health risk due to multiple low level indoor pollutants. PMID:26618504

  9. Focused Study on the Quiet Side Effect in Dwellings Highly Exposed to Road Traffic Noise

    PubMed Central

    Renterghem, Timothy Van; Botteldooren, Dick

    2012-01-01

    This study provides additional evidence for the positive effect of the presence of a quiet façade at a dwelling and aims at unraveling potential mechanisms. Locations with dominant road traffic noise and high Lden-levels at the most exposed façade were selected. Dwellings both with and without a quiet façade were deliberately sought out. Face-to-face questionnaires (N = 100) were taken to study the influence of the presence of a quiet side in relation to noise annoyance and sleep disturbance. As a direct effect, the absence of a quiet façade in the dwelling (approached as a front-back façade noise level difference smaller than 10 dBA) leads to an important increase of at least moderately annoyed people (odds-ratio adjusted for noise sensitivity equals 3.3). In an indirect way, a bedroom located at the quiet side leads to an even stronger reduction of the self-reported noise annoyance (odds-ratio equal to 10.6 when adjusted for noise sensitivity and front façade Lden). The quiet side effect seems to be especially applicable for noise sensitive persons. A bedroom located at the quiet side also reduces noise-induced sleep disturbances. On a loud side, bedroom windows are more often closed, however, conflicting with the preference of dwellers. PMID:23330222

  10. Phylogenetic evidence for recent diversification of obligate coral-dwelling gobies compared with their host corals☆

    PubMed Central

    Duchene, David; Klanten, Selma O.; Munday, Philip L.; Herler, Jürgen; van Herwerden, Lynne

    2013-01-01

    The rich diversity of coral reef organisms is supported, at least in part, by the diversity of coral reef habitat. Some of the most habitat specialised fishes on coral reefs are obligate coral-dwelling gobies of the genus Gobiodon that inhabit a range of coral species, mostly of the genus Acropora. However, the role of this specialised pattern of habitat use in the evolution of coral-dwelling gobies is not well understood. Diversification of coral-dwelling gobies may be driven by the diversification of their host corals (cospeciation), or alternatively, diversification of these fishes may have occurred independently of the diversification of host corals. The cospeciation hypothesis assumes similar timing in evolution of the gobies and their host corals. We used four genes for each group and the available fossil records to reconstruct and date phylogenies for 20 species of Gobiodon from the Indo-Pacific and the Red Sea, and for 28 species of the coral genus Acropora. Our results indicate that Gobiodon diversified mostly in the last ∼5 My, whereas Acropora corals have consistently diversified since the Eocene, making the hypothesis of cospeciation untenable. The fully resolved molecular phylogeny of the genus Gobiodon is in part at odds with previous analyses incorporating morphological data and indicates that some morphological traits form paraphyletic clades within Gobiodon. Our phylogeny supports a hypothesis in which Gobiodon diversified in the Indo-Pacific Ocean and then radiated recently, with multiple new variants found in the Red Sea. PMID:23680856

  11. Age-associated striatal dopaminergic denervation and falls in community-dwelling subjects

    PubMed Central

    Bohnen, Nicolaas I.; Muller, Martijn L. T. M.; Kuwabara, Hiroto; Cham, Rakié; Constantine, Gregory M.; Studenski, Stephanie A.

    2016-01-01

    Older adults have a high prevalence of gait and balance disturbances and falls. Normal aging is associated with significant striatal dopaminergic denervation, which might be a previously unrecognized additional contributor to geriatric falls. This study investigated the relationship between the severity of age-associated striatal dopaminergic denervation (AASDD) and falls in community-dwelling subjects. Community-dwelling subjects who did not have a clinical diagnosis to explain falls (n = 77: 43 female, 34 male; mean age 61.4 +/− 16.4; range 20–85) completed clinical assessment and brain dopamine transporter (DAT) [11C]beta-CFT (2-beta-carbomethoxy-3beta-(4-fluorophenyl) tropane) positron emission tomography imaging followed by 6 months of prospective fall monitoring using diaries. Results showed a significant inverse relationship between striatal DAT activity and age (r = −0.82, p < 0.001). A total of 26 subjects (33.8%) reported at least one fall, with 5 subjects (6.5%) reporting two or more falls. While no significant difference was noted in striatal DAT activity between nonfallers (n = 51) and fallers (n = 26; f = 0.02, not significant), striatal DAT activity was modestly reduced in the small subgroup of recurrent fallers compared with the other subjects (f = 5.07, p < 0.05). Findings indicate that AASDD does not explain isolated self-reported falls in community-dwelling subjects. However, it may be a contributing factor in the small subgroup of subjects with recurrent falls. PMID:20157861

  12. Geohydrologic, geochemical, and geologic controls on the occurrence of radon in ground water near Conifer, Colorado, USA

    USGS Publications Warehouse

    Lawrence, E.; Poeter, E.; Wanty, R.

    1991-01-01

    Integrated studies of geohydrology, geochemistry, and geology of crystalline rocks in the vicinity of Conifer, Colorado, reveal that radon concentrations do not correlate with variations in concentrations of other dissolved species. Concentrations of major ions show systematic variations along selected groundwater flowpaths, whereas radon concentrations are dependent on local geochemical and geologic phenomena (such as localized uranium concentration in the rock or the presence of faults or folds). When radon enters the flow system, concentrations do not increase along flowpaths because its decay rate is fast relative to groundwater flow rates. Radon-222 is not in secular equilibrium with 238U and 226Ra in the water. Therefore, most of the 238U and 226Ra necessary to support the waterborne 222Rn must be present locally in the rock. High concentrations of dissolved radon are not found in zones of high transmissivity, and transmissivity is not correlated with rock type in the study area. A higher transmissivity can be indicative of higher water-volume to rock-surface-area ratios, which could effectively dilute 222Rn entering the water and/or may indicate that emanated radon is carried away more rapidly. Water samples collected from individual wells over periods of several months showed significant fluctuations in the dissolved 222Rn content. This fluctuation may be controlled by changes in the contributions of water-producing zones within the well resulting from seasonal fluctuations of the water table and/or pumping stresses. ?? 1991.

  13. Application of kinetic model of bioaccumulation across a pH and salinity gradient for the prediction of cadmium uptake by the sediment dwelling Chironomidae

    SciTech Connect

    Bendell-Young, L.I.

    1999-05-01

    A kinetic model for the prediction of metal concentrations in aquatic organisms was applied for the prediction of cadmium concentrations in the sediment dwelling dipertan larvae, Chironomidae. Cadmium concentrations were determined in Chironomidae sampled along two distinct environmental gradients: (1) an acidity gradient (from pH 5.0--6.5) and (2) a salinity gradient. Comparison of predicted and observed values indicated that the kinetic model was successful in predicting concentrations in chironomids sampled along the acidity gradient but not the salinity gradient. Separation of routes of cadmium uptake into food and solute sources indicated that ingested sediment accounted for 60--100% of total invertebrate cadmium concentrations, however, the relative importance of water increased as a function of decreasing acidity and salinity. These results support the refinement of a kinetic model for predicting cadmium concentrations in sediment-living invertebrates, such as Chironomidae. By allowing for uptake from food and water the model highlighted the potential for routes of cadmium uptake to be pH and salinity dependent. For monitoring purposes, both vectors and the potential for the relative importance for each vector to change needs to be considered when assessing the degree of metal exposure to sediment ingesting invertebrates which inhabit systems with either a natural or anthropogenically induced garment in key water chemistry variables such as salinity or pH.

  14. Atmospheric radon, CO2 and CH4 dynamics in an Australian coal seam gas field

    NASA Astrophysics Data System (ADS)

    Tait, D. R.; Santos, I. R.; Maher, D. T.

    2013-12-01

    Atmospheric radon (222Rn), carbon dioxide (CO2), and methane concentrations (CH4) as well as carbon stable isotope ratios (δ13C) were used to gain insight into atmospheric chemistry within an Australian coal seam gas (CSG) field (Surat Basin, Tara region, Queensland). A˜3 fold increase in maximum 222Rn concentration was observed inside the gas field compared to outside of it. There was a significant relationship between maximum and average 222Rn concentrations and the number of gas wells within a 2 km to 4 km radius of the sampling sites (n = 5 stations; p < 0.05). We hypothesize that the radon relationship was a response to enhanced emissions within the gas field related to point sources (well heads, pipelines, etc.) and diffse soil sources due to changes in the soil structural and hydrological characteristics. A rapid qualitative assessment of CH4 and CO2 concentration, and carbon isotopes using a mobile cavity ring-down spectrometer system showed a widespread enrichment of both CH4 and CO2 within the production gas field. Concentrations of CH4 and CO2 were as high as 6.89 ppm and 541 ppm respectively compared average concentrations of 1.78 ppm (CH4) and 388 ppm (CO2) outside the gas field. The δ13C values showed distinct differences between areas inside and outside the production field with the δ13C value of the CH4 source within the field matching that of the methane in the CSG.

  15. Studies on radiation dose due to radioactive elements present in ground water and soil samples around Mysore city, India.

    PubMed

    Chandrashekara, M S; Veda, S M; Paramesh, L

    2012-04-01

    A systematic study of the ground water and soil samples collected from different locations around Mysore city (12(°)N and 76(°)E) has been carried out. (226)Ra activity concentration in water samples varies from 0.28 to 189 mBq l(-1) with a geometric mean (GM) of 4.75 mBq l(-1) and (222)Rn concentration in ground water varies from 4.25 to 435 Bq l(-1) with a GM of 25.9 Bq l(-1). The GM of inhalation and ingestion doses due to (222)Rn in water is 65.2 and 5.43, µSv y(-1), respectively. The measured GM gamma dose rate in air is 85.4 nGy h(-1) and absorbed dose rate estimated from the measured activity of radionuclides is 92.6 nGy h(-1). PMID:21764808

  16. Activity standardisation of ²²⁶Ra by 4πα liquid scintillation counting method.

    PubMed

    Havelka, Miroslav; Bluďovský, Richard

    2013-11-01

    Activity of (226)Ra in radium daughter products free solution was determined by 4πα liquid scintillation counting (LSC) method, where the detection efficiency of radium decay is practically equal to 1. The sources were prepared from solution with known (226)Ra mass concentration, from which, immediately before LS counting, (222)Rn and its daughter nuclides were removed by solvent extraction. LS counting results were corrected practically only for a <0.6% loss of radium from measured sample and for the ingrowth of (222)Rn and (218)Po concentrations in the sample after the separation was completed. The combined relative standard uncertainty was estimated to be lower than 0.34%. PMID:23602705

  17. Investigation of natural radioactivity levels in water around Kadugli, Sudan.

    PubMed

    Osman, Alfatih A A; Salih, Isam; Shaddad, Ibrahim A; El Din, Saif; Siddeeg, M B; Eltayeb, Hatem; Idriss, Hajo; Hamza, Walid; Yousif, E H

    2008-11-01

    Surface water from Miri Lake and groundwater from around Kadugli (West-Central Sudan) obtained by means of hand-pumps was analysed for (238)U, (226)Ra, (222)Rn, and (232)Th activity concentrations. The surface water showed very low levels of radionuclide concentrations: <1.0-7.5, 8.5-16.5, <1.6, and <0.1-0.39 mBq L(-1) for (238)U, (226)Ra, (222)Rn, and (232)Th, respectively. Groundwater revealed a significant amount of natural radioactivity (16.1-1720, 7.7-14.3, 3000-139,000, <0.1-39 mBq L(-1)) respectively. The overall annual effective dose was below the WHO reference dose level of 0.1 mSv yr(-1) except in one groundwater sample with an associated dose of 0.7 mSv yr(-1). PMID:18513978

  18. Naturally-Occurring Radionuclides In Drinking Water From Surface And Groundwater Reservoirs

    SciTech Connect

    Carvalho, F. P.; Madruga, M. J.; Oliveira, J. M.; Lopes, I.; Ferrador, G.; Sequeira, M. M.

    2008-08-07

    Radioactivity in water for human consumption is under closer scrutiny than ever before and many countries adopted guideline values based on total alpha and total beta activity measurements. Although most waters from surface circulation meet these guidelines, it is frequently found that groundwater exceed guideline values. Results of water analyses by alpha spectrometry clarified that the main radionuclides present are from the uranium decay series, such as uranium isotopes, radium ({sup 226}Ra), radon ({sup 222}Rn), and also {sup 210}Pb and {sup 210}Po. Occasionally, groundwater displayed {sup 226}Ra concentrations higher than 1 Bq L{sup -1} and {sup 222}Rn concentrations above 1000 Bq L{sup -1}. Nevertheless, lack of conformity of these waters with guidelines adopted, generally, is not due to anthropogenic inputs.

  19. Concentrating Radioactivity

    ERIC Educational Resources Information Center

    Herrmann, Richard A.

    1974-01-01

    By concentrating radioactivity contained on luminous dials, a teacher can make a high reading source for classroom experiments on radiation. The preparation of the source and its uses are described. (DT)

  20. Gamma Radiation Doses In Sweden

    NASA Astrophysics Data System (ADS)

    Almgren, Sara; Barregârd, Lars; Isaksson, Mats

    2008-08-01

    Gamma dose rate measurements were performed in one urban and one rural area using thermoluminescence dosimeters (TLD) worn by 46 participants and placed in their dwellings. The personal effective dose rates were 0.096±0.019(1 SD) and 0.092±0.016(1 SD)μSv/h in the urban and rural area, respectively. The corresponding dose rates in the dwellings were 0.11±0.042(1 SD) and 0.091±0.026(1 SD)μSv/h. However, the differences between the areas were not significant. The values were higher in buildings made of concrete than of wood and higher in apartments than in detached houses. Also, 222Rn measurements were performed in each dwelling, which showed no correlation with the gamma dose rates in the dwellings.

  1. Gamma Radiation Doses In Sweden

    SciTech Connect

    Almgren, Sara; Isaksson, Mats; Barregaard, Lars

    2008-08-07

    Gamma dose rate measurements were performed in one urban and one rural area using thermoluminescence dosimeters (TLD) worn by 46 participants and placed in their dwellings. The personal effective dose rates were 0.096{+-}0.019(1 SD) and 0.092{+-}0.016(1 SD){mu}Sv/h in the urban and rural area, respectively. The corresponding dose rates in the dwellings were 0.11{+-}0.042(1 SD) and 0.091{+-}0.026(1 SD){mu}Sv/h. However, the differences between the areas were not significant. The values were higher in buildings made of concrete than of wood and higher in apartments than in detached houses. Also, {sup 222}Rn measurements were performed in each dwelling, which showed no correlation with the gamma dose rates in the dwellings.

  2. Radon-222 and its parent radionuclides in groundwater from two study areas in New Jersey and Maryland, U.S.A.

    USGS Publications Warehouse

    Wanty, R.B.; Johnson, S.L.; Briggs, P.H.

    1991-01-01

    A study of groundwater chemistry and radionuclide mobility in New Jersey and Maryland was conducted to investigate natural processes that control the mobility of radionuclides in the water-rock system. Groundwater was sampled from two geological units in New Jersey and from six in Maryland. The water sampled was from aquifiers in fractured metamorphic rocks of varying composition and metamorphic grade. In both areas, groundwater chemistry was affected most by aquifier mineralogy and lithology; concentrations of total dissolved U, 226Ra and 222Rn were similarly affected. In evey sample for which measurements were made, dissolved Utotal and 226Ra were present in much lower concentrations than 222Rn when expressed in terms of their radioactivity. On the other hand, the total amount of 222Rn that could be produced in these rocks, given their U contents, is much higher than the concentrations observed in groundwater. Thus, the emanating efficiencies of the aquifer rocks studied must be near 10% or less. Such low emanating efficiencies require that a fraction of the 226Ra in the rock be located close to the water-rock interface so that 222Rn, when produced, can be rapidly and efficiently transferred to the aqueous phase. This condition is established when a similar fraction of the U is in a readily leachable position. No known U or Ra solids were supersaturated in any of the samples. Thus, adsorption processes probably play a role in limiting mobilities of Utotal and 226Ra. Concentrations of Utotal and 226Ra found in the water samples are comparable to those found in experimental studies of adsorption onto mineral surfaces. ?? 1991.

  3. Data Concentrator

    NASA Technical Reports Server (NTRS)

    Willett, Mike

    2015-01-01

    Orbital Research, Inc., developed, built, and tested three high-temperature components for use in the design of a data concentrator module in distributed turbine engine control. The concentrator receives analog and digital signals related to turbine engine control and communicates with a full authority digital engine control (FADEC) or high-level command processor. This data concentrator follows the Distributed Engine Controls Working Group (DECWG) roadmap for turbine engine distributed controls communication development that operates at temperatures at least up to 225 C. In Phase I, Orbital Research developed detailed specifications for each component needed for the system and defined the total system specifications. This entailed a combination of system design, compiling existing component specifications, laboratory testing, and simulation. The results showed the feasibility of the data concentrator. Phase II of this project focused on three key objectives. The first objective was to update the data concentrator design modifications from DECWG and prime contractors. Secondly, the project defined requirements for the three new high-temperature, application-specific integrated circuits (ASICs): one-time programmable (OTP), transient voltage suppression (TVS), and 3.3V. Finally, the project validated each design by testing over temperature and under load.

  4. Natural radioactivity in tap waters of Eastern Black Sea region of Turkey.

    PubMed

    Cevik, U; Damla, N; Karahan, G; Celebi, N; Kobya, A I

    2006-01-01

    In this study, the activity concentrations of some radionuclides in tap water samples of the Eastern Black Sea region of Turkey were measured. The activity concentrations of radionuclides (214)Pb, (214)Bi, (40)K, (226)Ra and (137)Cs were determined using high resolution gamma ray spectrometry. Furthermore, (222)Rn activity concentrations in tap water samples were measured using Liquid Scintillation Counting. The mean specific activities of (214)Pb, (214)Bi, (226)Ra, (40)K, (137)Cs and (222)Rn in tap water samples were 6.73, 6, 19.16, 168.57, 5.45 mBq l(-1) and 10.82 Bq l(-1), respectively. These values are comparable with concentrations reported for other countries. The effective doses were determined due to intake of these radionuclides as a consequence of direct consumption of tap water samples. The estimated effective doses were 6.878 x 10(-4) microSv y(-1) for (214)Pb, 4.800 x 10(-4) microSv y(-1) for (214)Bi, 3.916 microSv y(-1) for (226)Ra, 0.763 microSv y(-1) for (40)K, 0.052 microSv y(-1) for (137)Cs and 5.848 microSv y(-1) for (222)Rn. PMID:16030056

  5. Application of chaos analyses methods on East Anatolian Fault Zone fractures

    NASA Astrophysics Data System (ADS)

    Kamışlıoǧlu, Miraç; Külahcı, Fatih

    2016-06-01

    Nonlinear time series analysis techniques have large application areas on the geoscience and geophysics fields. Modern nonlinear methods are provided considerable evidence for explain seismicity phenomena. In this study nonlinear time series analysis, fractal analysis and spectral analysis have been carried out for researching the chaotic behaviors of release radon gas (222Rn) concentration occurring during seismic events. Nonlinear time series analysis methods (Lyapunov exponent, Hurst phenomenon, correlation dimension and false nearest neighbor) were applied for East Anatolian Fault Zone (EAFZ) Turkey and its surroundings where there are about 35,136 the radon measurements for each region. In this paper were investigated of 222Rn behavior which it's used in earthquake prediction studies.

  6. Radon radioactivity in groundwater from the Calabria region, south of Italy

    NASA Astrophysics Data System (ADS)

    Caridi, F.; D'Agostino, M.; Belvedere, A.; Marguccio, S.; Belmusto, G.

    2016-05-01

    In the present study the radon radioactivity in selected groundwater (boreholes and wells) from the Calabria region, south of Italy, was investigated. Water samples were analyzed by gamma spectrometry and by RAD7 + RAD H2O setup to determine the 222Rn activity concentration. Obtained values were used with the ingested dose conversion factor for 222Rn to estimate the annual effective dose for adult members of public due to consumption of the groundwater. The estimated average value was (88±5) μ Sv/y. It was compared with the estimated average annual effective dose due to ingestion of groundwater by the WHO (100 μ Sv/y) and that due to ingestion of food and water (290 μ Sv/y) by the UNSCEAR (2000). Results show that the presence of radon may not pose any radiological health hazard to the public due to the consumption of groundwater in the investigated region.

  7. Natural radioactivity in the scale of water well pipes.

    PubMed

    Aksoy, A; Al-Jarallah, M; Al-Haddad, M N

    2002-01-01

    The natural radioactivity of 226Ra and 228Ra in scale samples taken from pipes used in several local water wells was investigated. The results showed 226Ra activities to be varying from 1284 to 3613 Bq/kg whereas, the 228Ra concentrations did not show any significant variation, all being low, below 30 Bq/kg. The 222Rn exhalations from these scale samples were also measured and compared with the 226Ra contents. The average ratio of 222Rn/226Ra was 31%. Chemical analyses showed that the main constituent of the scale samples was iron. The radiation dose rates from the pipes and scale were up to 100nSv/h. Although not a major hazard this could present a long-term risk if the scale materials were handled indiscriminately. PMID:12113504

  8. Radiation exposure and dose to small mammals in radon-rich soils.

    PubMed

    Macdonald, C R; Laverock, M J

    1998-07-01

    Protection of the environment from radionuclide releases requires knowledge of the normal background levels of radiation exposure in the exposed biotic community and an estimate of the detriment caused by additional exposure. This study modeled the background exposure and dose to the lungs of small burrowing mammals from 222Rn in artificial burrows in radon-rich soils at a site in southeastern Manitoba. E-PERM chambers used to measure 222Rn in soil showed good reproducibility of measurement, with an average coefficient of variance (CV) of about 10%. Geometric mean (GM) 222Rn concentrations at nine randomly selected sites ranged from 5,490 Bq/m3 (GSD = 1.57, n = 7) to 41,000 Bq/m3 (GSD = 1.02, n = 5). Long-term monitoring of 222Rn concentrations in artificial burrows showed large variation within and between burrows and did not show consistent variation with season, orientation of the burrow opening, or levels of 226Ra in the soil. Annual GM concentrations in individual burrows ranged from 7,480 Bq/m3 (GSD = 1.60) to 18,930 Bq/m3 (GSD = 1.81) in burrows several meters apart. A grand GM of 9,990 Bq/m3 (GSD = 1.81, n = 214) was measured over the site for the year. An exposure model was constructed for five small mammal species based on their respiration rates and the number of hours spent in the burrow, active or hibernating, exposed to soil gas 222Rn, and the time spent out of the burrow exposed to atmospheric 222Rn. A background dose of 0.9 mGy/a from atmospheric 222Rn (40 Bq/m3) was estimated for a large-bodied (80 kg), nonburrowing animal living on the soil surface. The highest exposures (mJ/a) in burrowing mammals occurred in those species with the highest respiration rates. Hibernation accounted for a small fraction of total annual exposure (<5%) because of very low respiration rates during this period. Absorbed dose to lung (mGy/a) was highest in the pocket gopher and decreased in the larger animals because of larger lung mass. Using mean 222Rn concentrations

  9. Seismic vulnerability of dwellings at Sete Cidades Volcano (S. Miguel Island, Azores)

    NASA Astrophysics Data System (ADS)

    Gomes, A.; Gaspar, J. L.; Queiroz, G.

    2006-01-01

    Since the settlement of S. Miguel Island (Azores), in the XV century, several earthquakes caused important human losses and severe damages on the island. Sete Cidades Volcano area, located in the westernmost part of the island, was attained by strong seismic crises of tectonic and volcanic origin and major events reached a maximum historical intensity of IX (European Macroseismic Scale 1998) in this zone. Aiming to evaluate the impact of a future major earthquakes, a field survey was carried out in ten parishes of Ponta Delgada County, located on the flanks of Sete Cidades volcano and inside it is caldera. A total of 7019 buildings were identified, being 4351 recognized as dwellings. The total number of inhabitants in the studied area is 11429. In this work, dwellings were classified according to their vulnerability to earthquakes (Classes A to F), using the structure types table of the EMS-98, adapted to the types of constructions made in the Azores. It was concluded that 76% (3306) of the houses belong to Class A, and 17% (740) to Class B, which are the classes of higher vulnerability. If the area is affected by a seismic event with intensity IX it is estimated, that 57% (2480) to 77% (3350) of the dwellings will partially or totally collapse and 15% (652) to 25% (1088) will need to be rehabilitated. In this scenario, considering the average of inhabitants per house for each parish, 82% (9372) to 92% (10515) of the population will be affected. The number of deaths, injured and dislodged people will pose severe problems to the civil protection authorities and will cause social and economic disruption in the entire archipelago.

  10. Predicting sarcopenia from functional measures among community-dwelling older adults.

    PubMed

    Gray, Michelle; Glenn, Jordan M; Binns, Ashley

    2016-02-01

    Sarcopenia is defined as age-related lean tissue mass (LTM) loss resulting in reduced muscular strength, physical function, and mobility. Up to 33 % of older adults currently are sarcopenic, with likely many more undiagnosed. The purpose of this investigation was to predict sarcopenia status from easily accessible functional measures of community-dwelling older adults. Forty-three community-dwelling older adults (n = 32 females and n = 11 males) participated in the present investigation. Inclusion criteria included ≥65 years of age, mini-mental state examination score ≥24, and no falls within previous 12 months. All subjects completed their appendicular skeletal mass (ASM) assessment via dual-energy X-ray absorptiometry (DXA) and were categorized as either sarcopenic or non-sarcopenic. Physical assessments included 10-m usual walk, hand-grip (HG) strength, 6-min walk, 8-ft up-and-go, 30-s chair stand, 30-s arm curl, and sit-to-stand muscular power. A forward, stepwise multiple regression analysis revealed that age, sex, weight, height, 10-m walk, HG, and sit-to-stand muscular power account for 96.1 % of the variance in ASM. The area under the curve was 0.92 for correctly identifying sarcopenic participants compared to their actual classification. This is the first prediction model used to identify sarcopenia based on parameters of demographic and functional fitness measures in community-dwelling older adults. The ability to accurately identify sarcopenia in older adults is imperative to their quality of life and ability to perform activities of daily living. PMID:26846414

  11. Exercise rehabilitation on home-dwelling patients with Alzheimer's disease - a randomized, controlled trial. Study protocol

    PubMed Central

    2010-01-01

    Background Besides cognitive decline, Alzheimer's disease (AD) leads to physical disability, need for help and permanent institutional care. The trials investigating effects of exercise rehabilitation on physical functioning of home-dwelling older dementia patients are still scarce. The aim of this study is to investigate the effectiveness of intensive exercise rehabilitation lasting for one year on mobility and physical functioning of home-dwelling patients with AD. Methods During years 2008-2010, patients with AD (n = 210) living with their spousal caregiver in community are recruited using central AD registers in Finland, and they are offered exercise rehabilitation lasting for one year. The patients are randomized into three arms: 1) tailored home-based exercise twice weekly 2) group-based exercise twice weekly in rehabilitation center 3) control group with usual care and information of exercise and nutrition. Main outcome measures will be Guralnik's mobility and balance tests and FIM-test to assess physical functioning. Secondary measures will be cognition, neuropsychiatric symptoms according to the Neuropsychiatric Inventory, caregivers' burden, depression and health-related quality of life (RAND-36). Data concerning admissions to institutional care and the use and costs of health and social services will be collected during a two year follow-up. Discussion To our knowledge this is the first large scale trial exploring whether home-dwelling patients with AD will benefit from intense and long-lasting exercise rehabilitation in respect to their mobility and physical functioning. It will also provide data on cost-effectiveness of the intervention. Trial registration ACTRN12608000037303 PMID:20925948

  12. Widespread geographical distribution of mitochondrial haplotypes in rock-dwelling cichlid fishes from Lake Tanganyika.

    PubMed

    Meyer, A; Knowles, L L; Verheyen, E

    1996-06-01

    The spectacularly diverse cichlid fish species flocks of the East African Rift Lakes have elicited much debate on the potential evolutionary mechanisms responsible for the origin of these adaptive radiations. An historical perspective on population structure may offer insights into the processes driving population differentiation and possibly speciation. Here, we examine mitochondrial DNA (mtDNA) sequence variation in two endemic species of rock-dwelling cichlids, Simochromis babaulti and S. diagramma, from Lake Tanganyika. Phylogeographic analyses were used to infer what factors might have been important in the genetic structuring of Simochromis populations. Patterns of mtDNA differentiation in Simochromis were compared to those of other rock-dwelling cichlids to distinguish between competing hypotheses concerning the processes underlying their evolution. In striking contrast to previous findings, populations of Simochromis, even those separated by up to 300 km, were found to share mitochondrial DNA haplotypes. There is no correspondence between mtDNA genealogies and the geographical distribution of populations. Only S. babaulti, but not S. diagramma was found to have a significant association between genetic and geographic distance. These phylogeographic patterns suggest that the evolutionary effects of abiotic and biotic factors shaping population genetic structure may differ substantially even among closely related species of rock-dwelling cichlids. Physical events and barriers to gene flow that are believed to have had a major impact on the geographical distribution and intralacustrine speciation of Tropheus do not seem to have equally strongly affected its close relative Simochromis. These findings emphasize that no single mechanism can be responsible for the formation of population structure, speciation, and the adaptive radiation of all cichlid fishes. PMID:8688956

  13. National impacts of the Weatherization Assistance Program in single-family and small multifamily dwellings

    SciTech Connect

    Brown, M.A.; Berry, L.G.; Balzer, R.A.; Faby, E.

    1993-05-01

    Since 1976, the US Department of Energy (DOE) has operated one of the largest energy conservation programs in the nation -- the low-income Weatherization Assistance Program. The program strives to increase the energy efficiency of dwellings occupied by low-income persons in order to reduce their energy consumption, lower their fuel bills, increase the comfort of their homes, and safeguard their health. It targets vulnerable groups including the elderly, people with disabilities, and families with children. The most recent national evaluation of the impacts of the Program was completed in 1984 based on energy consumption data for households weatherized in 1981. DOE Program regulations and operations have changed substantially since then: new funding sources, management principles, diagnostic procedures, and weatherization technologies have been incorporated. Many of these new features have been studied in isolation or at a local level; however, no recent evaluation has assessed their combined, nationwide impacts to date or their potential for the future. In 1990, DOE initiated such an evaluation. This evaluation is comprised of three ``impact`` studies (the Single-Family Study, High-Density Multifamily Study, and Fuel-Oil Study) and two ``policy`` studies. Altogether, these five studies will provide a comprehensive national assessment of the Weatherization Assistance Program as it existed in the 1989 Program Year (PY 1989). This report presents the results of the first phase of the Single-Family Study. It evaluates the energy savings and cost effectiveness of the Program as it has been applied to the largest portion of its client base -- low-income households that occupy single-family dwellings, mobile homes, and small (2- to 4-unit) multifamily dwellings. It is based upon a representative national sample that covers the full range of conditions under which the program was implemented in PY 1989.

  14. Challenges of Achieving 2012 IECC Air Sealing Requirements in Multifamily Dwellings

    SciTech Connect

    Klocke, S.; Faakye, O.; Puttagunta, S.

    2014-10-01

    ​While previous versions of the International Energy Conservation Code (IECC) have included provisions to improve the air tightness of dwellings, for the first time, the 2012 IECC mandates compliance verification through blower door testing. Simply completing the Air Barrier and Insulation Installation checklist through visual inspection is no longer sufficient by itself. In addition, the 2012 IECC mandates a significantly stricter air sealing requirement. In Climate Zones 3 through 8, air leakage may not exceed 3 ACH50, which is a significant reduction from the 2009 IECC requirement of 7 ACH50. This requirement is for all residential buildings, which includes low-rise multifamily dwellings. While this air leakage rate requirement is an important component to achieving an efficient building thermal envelope, currently, the code language doesn't explicitly address differences between single family and multifamily applications. In addition, the 2012 IECC does not provide an option to sample dwellings for larger multifamily buildings, so compliance would have to be verified on every unit. With compliance with the 2012 IECC air leakage requirements on the horizon, several of CARB's multifamily builder partners are evaluating how best to comply with this requirement. Builders are not sure whether it is more practical or beneficial to simply pay for guarded testing or to revise their air sealing strategies to improve compartmentalization to comply with code requirements based on unguarded blower door testing. This report summarizes CARB's research that was conducted to assess the feasibility of meeting the 2012 IECC air leakage requirements in 3 multifamily buildings.

  15. Challenges of Achieving 2012 IECC Air Sealing Requirements in Multifamily Dwellings

    SciTech Connect

    Klocke, S.; Faakye, O.; Puttagunta, S.

    2014-10-01

    While previous versions of the International Energy Conservation Code (IECC) have included provisions to improve the air tightness of dwellings, for the first time, the 2012 IECC mandates compliance verification through blower door testing. Simply completing the Air Barrier and Insulation Installation checklist through visual inspection is no longer sufficient by itself. In addition, the 2012 IECC mandates a significantly stricter air sealing requirement. In Climate Zones 3 through 8, air leakage may not exceed 3 ACH50, which is a significant reduction from the 2009 IECC requirement of 7 ACH50. This requirement is for all residential buildings, which includes low-rise multifamily dwellings. While this air leakage rate requirement is an important component to achieving an efficient building thermal envelope, currently, the code language doesn't explicitly address differences between single family and multifamily applications. In addition, the 2012 IECC does not provide an option to sample dwellings for larger multifamily buildings, so compliance would have to be verified on every unit. With compliance with the 2012 IECC air leakage requirements on the horizon, several of Consortium for Advanced Residential Building's (CARB’s) multifamily builder partners are evaluating how best to comply with this requirement. Builders are not sure whether it is more practical or beneficial to simply pay for guarded testing or to revise their air sealing strategies to improve compartmentalization to comply with code requirements based on unguarded blower door testing. This report summarizes CARB's research that was conducted to assess the feasibility of meeting the 2012 IECC air leakage requirements in 3 multifamily buildings.

  16. Purpose in Life Is Associated With Mortality Among Community-Dwelling Older Persons

    PubMed Central

    Boyle, Patricia A.; Barnes, Lisa L.; Buchman, Aron S.; Bennett, David A.

    2009-01-01

    Objective To assess the association between purpose in life as an important determinant of health outcomes and mortality in community-dwelling elderly persons. Methods We used data from 1238 older persons without dementia from two longitudinal cohort studies (Rush Memory and Aging Project and Minority Aging Research Study) with baseline evaluations of purpose in life and up to 5 years of follow-up to test the hypothesis that greater purpose in life is associated with a reduced risk of mortality among community-dwelling older persons. Results The mean ± standard deviation score on the purpose in life measure at baseline was 3.7 ± 0.5 (range = 2−5), with higher scores indicating greater purpose in life. During the 5-year follow-up (mean = 2.7 years), 151 of 1238 persons (12.2%) died. In a proportional hazards model adjusted for age, sex, education, and race, a higher level of purpose in life was associated with a substantially reduced risk of mortality (hazard ratio = 0.60, 95% Confidence Interval = 0.42, 0.87). Thus, the hazard rate for a person with a high score on the purpose in life measure (score = 4.2, 90th percentile) was about 57% of the hazard rate of a person with a low score (score = 3.1, 10th percentile). The association of purpose in life with mortality did not differ among men and women or Whites and Blacks. Further, the finding persisted after the addition of terms for several potential confounders, including depressive symptoms, disability, neuroticism, the number of chronic medical conditions, and income. Conclusion Greater purpose in life is associated with a reduced risk of all-cause mortality among community-dwelling older persons. PMID:19414613

  17. Sex-specific differences in risk factors for sarcopenia amongst community-dwelling older adults.

    PubMed

    Tay, L; Ding, Y Y; Leung, B P; Ismail, N H; Yeo, A; Yew, S; Tay, K S; Tan, C H; Chong, M S

    2015-12-01

    With considerable variation including potential sex-specific differential rate of skeletal muscle loss, identifying modifiable factors for sarcopenia will be pivotal to guide targeted interventions. This study seeks to identify clinical and biological correlates of sarcopenia in community-dwelling older adults, with emphasis on the role of anabolic and catabolic stimuli, and special reference to gender specificity. In this cross-sectional study involving 200 community-dwelling and functionally independent older adults aged ≥50 years, sarcopenia was defined using the Asian Working Group for Sarcopenia criteria. Comorbidities, cognitive and functional performance, physical activity and nutritional status were routinely assessed. Biochemical parameters included haematological indices, lipid panel, vitamin D level, anabolic hormones [insulin-like growth factor-1 (IGF-1), free testosterone (males only)] and catabolic markers [inflammatory markers (interleukin-6, C-reactive protein) and myostatin]. Multiple logistic regression was performed to identify independent predictors for sarcopenia. Age was associated with sarcopenia in both genders. Malnutrition conferred significantly higher odds for sarcopenia in women (OR = 5.71, 95% CI 1.13-28.84.44, p = 0.035) while higher but acceptable range serum triglyceride was protective in men (OR = 0.05, 95% CI 0.00-0.52, p = 0.012). Higher serum myostatin independently associated with higher odds for sarcopenia in men (OR = 1.11, 95% CI 1.00-1.24, p = 0.041). Serum IGF-1 was significantly lower amongst female sarcopenic subjects, with demonstrable trend for protective effect against sarcopenia in multiple regression models, such that each 1 ng/ml increase in IGF-1 was associated with 1% decline in odds of sarcopenia in women (p = 0.095). Our findings support differential pathophysiological mechanisms for sarcopenia that, if corroborated, may have clinical utility in guiding sex-specific targeted

  18. DOE Zero Energy Ready Home Case Study: Dwell Development, Seattle, Washington

    SciTech Connect

    none,

    2013-09-01

    This Challenge Home is one of 42 homes in a micro-community of ultra-modern, energy-efficient homes built by Dwell Development on an urban gray-field site in South Seattle. Every home will achieve a 5-Star Built Green rating from the regional master builders association and meet the criteria of the Northwest ENERGY STAR program, which is more strict than the national ENERGY STAR criteria. Also, the home won a 2013 Housing Innovation Award in the "systems builder" category.

  19. Economic analysis of a passive solar multiple-family dwelling for upstate New York

    SciTech Connect

    Laquatra, J. Jr.

    1982-02-01

    The objective of this study was to examine the economic feasibility of passive solar energy as applied to a multiple-family dwelling in three upstate New York cities: Buffalo, Rochester, and Syracuse. Specifically, two passive solar applications - a Trombe wall and a direct-gain system - for a nine-unit structure designed by Total Environmental Action, Inc. were analyzed through the use of a solar economic performance code. City-specific data, including climatological information, building construction costs, utility rates, and property taxes were used, as were various economic parameters to reflect economic conditions in general and specifically those of the solar systems' owners.

  20. To what factors do rural-dwelling hispanics attribute depressive symptoms?

    PubMed

    Vahia, Ipsit V; Camacho, Alvaro; Depp, Colin A; Herrera, Angelica; Thompson, Wesley K; Munoz, Rodrigo; Jeste, Dilip V; Ng, Bernardo

    2013-01-01

    This study is a retrospective chart review comparing rural-dwelling Caucasian and Hispanic outpatients' attribution of depressive symptoms. Based on the data gathered at intake, Hispanics were more likely to attribute depression to curse/spell and supernatural causes, while Caucasians were more likely to attribute symptoms to hereditary factors or job stress. Among both groups, higher CESD score was associated with problems with significant others or how they got along with others. Among Hispanics, depression severity was additionally associated with problems related to job or finances. Our findings point to a consequential role for clinical inquiry into attributed causes of depressive symptoms. PMID:23781333

  1. Sleep Quality, Pain and Self-Efficacy among Community-Dwelling Adults with Sickle Cell Disease.

    PubMed

    Adegbola, Maxine

    2015-07-01

    The aim of this paper was to report the findings of a study examining relationships among sleep, pain, self-efficacy, and demographic attributes of community-dwelling adults with sickle cell disease (SCD). Sleep difficulty has been self-reported among adults with chronic pain. Past studies have demonstrated that chronic pain results in sleep difficulties and other complications that threaten effective functioning. Community-dwelling adults with SCD are living longer and need to be evaluated for sleep quality, pain, and self-efficacy. Little is known about whether adults with SCD-related pain have disturbances in sleep and self-efficacy, and if these disturbances are affected by age and/or gender. The purpose of this descriptive, correlational study was to examine the relationships among sleep, pain, self-efficacy, and demographic attributes among community-dwelling adults with SCD, and who use support services of state SCD Associations in the United States. For this secondary data analysis, the study was conducted from June, 2014 to December, 2014 and used a descriptive correlational design to analyze data from a primary study of a convenience sample of 90 subjects with SCD, who were 18 years of age and older. Linear regression was used to compute the relationship between dependent and independent variables. All measures were self-reported. It was found that gender did not significantly affect reports of sleep, pain, or self-efficacy. Self-efficacy accounted for direct relationships with sleep and inverse relationships with pain. Some individuals (16.7%) reported sleeping very well, however, the majority (83.3%) was not sleeping very well, and a greater number of individuals (93.3%) reported having some pain. Among adults with chronic SCD pain, self-efficacy is important in maintaining a stable quality of health. Future assessments, interventions, and research should include comprehensive sleep and pain evaluations, and measures to improve self-efficacy and sleep

  2. Thalassinoides burrows (decapoda dwelling structures) in lower cretaceous sections of southwestern and central Crimea

    NASA Astrophysics Data System (ADS)

    Yanin, B. T.; Baraboshkin, E. Yu.

    2013-05-01

    Burrows of Thalassinoides, which are attributed to the group of dwelling structures, occur in all the marine and coastal facies. The Lower Cretaceous sections of southwestern and central Crimea yielded the representative collection of Thalassinoides burrows belonging to the ichnospecies Th. suevicus (Rieth, 1932), which served as an object for this investigation. The burrows are confined to coarse-grained terrigenous, carbonate, and mixed sediments and contain assemblages of ichnofossils indicating coastal and shallow-water marine Skolithos and Cruziana ichnofacies. In the Mesozoic-Cenozoic, the producers of the Thalassinoides burrows were decapods, confirmed by finds of crayfish Hoploparia in them.

  3. Nutrition education intervention with community-dwelling older adults: research challenges and opportunities.

    PubMed

    Lyons, Beverly P

    2014-08-01

    This study critically reviewed empirical literature examining nutrition education intervention studies with community-dwelling older adults over the period 2003-2012 to: (1) determine the number, (2) evaluate the research designs, and (3) report the study outcomes. A search of online databases yielded 74 studies six of which met our criteria. The studies reported favorable intervention outcomes. Because of the number, variability in the types, designs, measures, scope, educational and behavioral strategies, results can only inform future studies and encourage scholars to use strong evaluation design. We recommend the utilization of an ecological conceptual model when conducting nutrition interventions studies and discussed implications in terms of research and practice. PMID:24368631

  4. Falls and Fall-Related Injuries among Community-Dwelling Adults in the United States

    PubMed Central

    Verma, Santosh K.; Willetts, Joanna L.; Corns, Helen L.; Marucci-Wellman, Helen R.; Lombardi, David A.; Courtney, Theodore K.

    2016-01-01

    Introduction Falls are the leading cause of unintentional injuries in the U.S.; however, national estimates for all community-dwelling adults are lacking. This study estimated the national incidence of falls and fall-related injuries among community-dwelling U.S. adults by age and gender and the trends in fall-related injuries across the adult life span. Methods Nationally representative data from the National Health Interview Survey (NHIS) 2008 Balance and Dizziness supplement was used to develop national estimates of falls, and pooled data from the NHIS was used to calculate estimates of fall-related injuries in the U.S. and related trends from 2004–2013. Costs of unintentional fall-related injuries were extracted from the CDC’s Web-based Injury Statistics Query and Reporting System. Results Twelve percent of community-dwelling U.S. adults reported falling in the previous year for a total estimate of 80 million falls at a rate of 37.2 falls per 100 person-years. On average, 9.9 million fall-related injuries occurred each year with a rate of 4.38 fall-related injuries per 100 person-years. In the previous three months, 2.0% of older adults (65+), 1.1% of middle-aged adults (45–64) and 0.7% of young adults (18–44) reported a fall-related injury. Of all fall-related injuries among community-dwelling adults, 32.3% occurred among older adults, 35.3% among middle-aged adults and 32.3% among younger adults. The age-adjusted rate of fall-related injuries increased 4% per year among older women (95% CI 1%–7%) from 2004 to 2013. Among U.S. adults, the total lifetime cost of annual unintentional fall-related injuries that resulted in a fatality, hospitalization or treatment in an emergency department was 111 billion U.S. dollars in 2010. Conclusions Falls and fall-related injuries represent a significant health and safety problem for adults of all ages. The findings suggest that adult fall prevention efforts should consider the entire adult lifespan to ensure a

  5. Sleep Quality, Pain and Self-Efficacy among Community-Dwelling Adults with Sickle Cell Disease

    PubMed Central

    Adegbola, Maxine

    2016-01-01

    The aim of this paper was to report the findings of a study examining relationships among sleep, pain, self-efficacy, and demographic attributes of community-dwelling adults with sickle cell disease (SCD). Sleep difficulty has been self-reported among adults with chronic pain. Past studies have demonstrated that chronic pain results in sleep difficulties and other complications that threaten effective functioning. Community-dwelling adults with SCD are living longer and need to be evaluated for sleep quality, pain, and self-efficacy. Little is known about whether adults with SCD-related pain have disturbances in sleep and self-efficacy, and if these disturbances are affected by age and/or gender. The purpose of this descriptive, correlational study was to examine the relationships among sleep, pain, self-efficacy, and demographic attributes among community-dwelling adults with SCD, and who use support services of state SCD Associations in the United States. For this secondary data analysis, the study was conducted from June, 2014 to December, 2014 and used a descriptive correlational design to analyze data from a primary study of a convenience sample of 90 subjects with SCD, who were 18 years of age and older. Linear regression was used to compute the relationship between dependent and independent variables. All measures were self-reported. It was found that gender did not significantly affect reports of sleep, pain, or self-efficacy. Self-efficacy accounted for direct relationships with sleep and inverse relationships with pain. Some individuals (16.7%) reported sleeping very well, however, the majority (83.3%) was not sleeping very well, and a greater number of individuals (93.3%) reported having some pain. Among adults with chronic SCD pain, self-efficacy is important in maintaining a stable quality of health. Future assessments, interventions, and research should include comprehensive sleep and pain evaluations, and measures to improve self-efficacy and sleep

  6. Chemical reaction rates and entrainment within the Endeavour Ridge hydrothermal plume

    NASA Astrophysics Data System (ADS)

    Kadko, D. C.; Rosenberg, N. D.; Lupton, J. E.; Collier, R. W.; Lilley, M. D.

    1990-09-01

    The aging of the hydrothermal plume over the Endeavour segment of the Juan de Fuca Ridge was estimated by measuring the 222Rn 3He ratio in the plume as it dispersed. Despite uncertainties in the source function of hydrothermal input, it wa determined that the relative sequence of removal from the plume is H 2 > Δc > 222Rn>CH 4 ≫Mn , where Δc is a measure of particle concentration and the mean life of 222Rn is 5.5 days. H 2 is removed from the plume within hours of input while Mn is not removed within the two-week timescale of the radon-helium clock. Entrainment of bottom water within the buoyant plume may introduce additional chemical signatures into the spreading effluent layer over that which would be introduced by hydrothermal discharge alone. This is particularly significant for those chemical species which are not greatly enriched in the vent fluids relative to bottom water concentration and which display a nutrient-like profile in the deep ocean. Thus we found that significant fractions of the Si and 226Ra anomalies in the plume were not of hydrothermal origin but were derived from entrained bottom water which has a higher concentration of these elements than ambient water at plume height.

  7. Radon reduction using sub floor fans

    SciTech Connect

    Harley, N.H.; Chittaporn, P.

    1996-06-01

    The basement and second floor {sup 222}Rn concentrations in an energy efficient home were measured hourly for 6 y using continuous monitors of our design. The home had a subslab pipe network installed during construction, and for the past 2 y a 150 cfm fan was operative venting air via ductwork inside the chimney exiting on the roof. During this measurement interval, experiments were conducted with the fan in 3 modes: (1) with the subslab fan off, (2) in the conventional direction auctioning air from beneath the slab to outside, and (3) reversed, blowing outdoor air into the network under the slab. We have a large data base to show that the indoor {sup 222}R n concentration varies inversely with the indoor/outdoor temperature difference. In order to compare the 3 fan modes directly, we selected 50 to 90 d periods when the outdoor temperature was essentially the same. For the 3 modes, the fan off, blowing upward, and blowing downward, the basement concentration averaged 80, 38, and 34 Bq m{sup -3}, respectively. Radon peaks or surges occur over a period of about 1 d during falling barometric pressure. With the fan blowing downward, these {sup 222}Rn peaks tend to be smaller but only marginally so. We conclude that in this home the reduction in {sup 222}Rn with the fan and subslab pipe network operating was essentially the same regardless of the direction of flow from the fan.

  8. Nontarget effects of ivermectin residues on earthworms and springtails dwelling beneath dung of treated cattle in four countries.

    PubMed

    Scheffczyk, Adam; Floate, Kevin D; Blanckenhorn, Wolf U; Düring, Rolf-Alexander; Klockner, Andrea; Lahr, Joost; Lumaret, Jean-Pierre; Salamon, Jörg-Alfred; Tixier, Thomas; Wohde, Manuel; Römbke, Jörg

    2016-08-01

    The authorization of veterinary medicinal products requires that they be assessed for nontarget effects in the environment. Numerous field studies have assessed these effects on dung organisms. However, few studies have examined effects on soil-dwelling organisms, which might be exposed to veterinary medicinal product residues released during dung degradation. The authors compared the abundance of earthworms and springtails in soil beneath dung from untreated cattle and from cattle treated 0 d, 3 d, 7 d, 14 d, and 28 d previously with ivermectin. Study sites were located in different ecoregions in Switzerland (Continental), The Netherlands (Atlantic), France (Mediterranean), and Canada (Northern Mixed Grassland). Samples were collected using standard methods from 1 mo to 12 mo after pat deposition. Ivermectin concentrations in soil beneath dung pats ranged from 0.02 mg/kg dry weight (3 mo) to typically <0.006 mg/kg dry weight (5-7 mo). Earthworms were abundant and species-rich at the Swiss and Dutch sites, less common with fewer species at the French site, and essentially absent at the Canadian site. Diverse but highly variable communities of springtails were present at all sites. Overall, results showed little effect of residues on either earthworms or springtails. The authors recommend that inclusion of soil organisms in field studies to assess the nontarget effects of veterinary medicinal products be required only if earthworms or springtails exhibit sensitivity to the product in laboratory tests. Environ Toxicol Chem 2016;35:1959-1969. © 2015 SETAC. PMID:26565894

  9. Effect of sulfidation and dissolved organic matters on toxicity of silver nanoparticles in sediment dwelling organism, Chironomus riparius.

    PubMed

    Lee, Si-Won; Park, Sun-Young; Kim, Younghun; Im, Hosub; Choi, Jinhee

    2016-05-15

    The properties, fate, and toxicity of silver nanoparticles (AgNPs) are readily modified in the environment. Thus, in order to predict the environmental impact of AgNPs, the toxicity test should be conducted to assess the interactions of AgNPs with environmental matrices. Dissolved organic matter (DOM) is known to mitigate AgNPs toxicity in natural systems, and it is also known that silver binds strongly to sulfur. Little is known, however, about the effect of sulfidation and to what extent it could compete with DOM in the sediment. We therefore investigated the effect of sulfide on a sediment dwelling organism, Chironomus riparius using ecotoxicity endpoints. We then investigated how sulfide and a combination of sulfide and DOM affect the toxicity of AgNPs in C. riparius. We also monitored the concentrations of silver in the water and sediment compartments, as well as in C. riparius tissue, in the presence and absence of sulfide. Finally, in order to investigate how sulfide and DOM affect the release of ions from AgNPs, we also monitored released Ag(+) in each treatment. In the presence of sulfide, AgNPs were found to be less toxic to C. riparius in acute and chronic endpoints than AgNPs alone, whereas DOM treatment did not modulate the toxicity of AgNPs. Sulfide treatment reduced the release of Ag(+) from AgNPs. Water-spiked AgNPs with sulfide were found to be more slowly incorporated into both sediment and larvae as compared to the AgNP alone. Overall, the results suggest that the presence of sulfide in sediment mitigates the ecotoxicity of AgNPs in C. riparius. PMID:26938319

  10. Output regulation of switched linear multi-agent systems: an agent-dependent average dwell time method

    NASA Astrophysics Data System (ADS)

    Jia, Hongwei; Zhao, Jun

    2016-08-01

    The output regulation problem of switched linear multi-agent systems with stabilisable and unstabilisable subsystems is investigated in this paper. A sufficient condition for the solvability of the problem is given. Owing to the characteristics of switched multi-agent systems, even if each agent has its own dwell time, the multi-agent systems, if viewed as an overall switched system, may not have a dwell time. To overcome this difficulty, we present a new approach, called an agent-dependent average dwell time method. Due to the limited information exchange between agents, a distributed dynamic observer network for agents is provided. Further, a distributed dynamic controller based on observer is designed. Finally, simulation results show the effectiveness of the proposed solutions.

  11. Health risks due to radon in drinking water

    USGS Publications Warehouse

    Hopke, P.K.; Borak, T.B.; Doull, J.; Cleaver, J.E.; Eckerman, K.F.; Gundersen, L.C.S.; Harley, N.H.; Hess, C.T.; Kinner, N.E.; Kopecky, K.J.; Mckone, T.E.; Sextro, R.G.; Simon, S.L.

    2000-01-01

    Following more than a decade of scientific debate about the setting of a standard for 222Rn in drinking water, Congress established a timetable for the promulgation of a standard in the 1996 Amendments to the Safe Drinking Water Act. As a result of those Amendments, the EPA contracted with the National Academy of Sciences to undertake a risk assessment for exposure to radon in drinking water. In addition, the resulting committee was asked to address several other scientific issues including the national average ambient 222Rn concentration and the increment of 222Rn to the indoor- air concentration arising from the use of drinking water in a home. A new dosimetric analysis of the cancer risk to the stomach from ingestion was performed. The recently reported risk estimates developed by the BEIR VI Committee for inhalation of radon decay products were adopted. Because the 1996 Amendments permit states to develop programs in which mitigation of air- producing health-risk reductions equivalent to that which would be achieved by treating the drinking water, the scientific issues involved in such 'multimedia mitigation programs' were explored.

  12. Higher Lipoprotein (a) Levels Are Associated with Better Pulmonary Function in Community-Dwelling Older People – Data from the Berlin Aging Study II

    PubMed Central

    Buchmann, Nikolaus; Kassner, Ursula; Norman, Kristina; Goldeck, David; Eckardt, Rahel; Pawelec, Graham; Steinhagen-Thiessen, Elisabeth; Demuth, Ilja

    2015-01-01

    Reduced pulmonary function and elevated serum cholesterol levels are recognized risk factors for cardiovascular disease. Currently, there is some controversy concerning relationships between cholesterol, LDL-cholesterol, HDL-cholesterol, serum triglycerides and lung function. However, most previous studies compared patients suffering from chronic obstructive pulmonary disease (COPD) with healthy controls, and only a small number examined this relationship in population-based cohorts. Moreover, lipoprotein a [Lp(a)], another lipid parameter independently associated with cardiovascular diseases, appears not to have been addressed at all in studies of lung function at the population level. Here, we determined relationships between lung function and several lipid parameters including Lp(a) in 606 older community-dwelling participants (55.1% women, 68±4 years old) from the Berlin Aging Study II (BASE-II). We found a significantly lower forced expiration volume in 1 second (FEV1) in men with low Lp(a) concentrations (t-test). This finding was further substantiated by linear regression models adjusting for known covariates, showing that these associations are statistically significant in both men and women. According to the highest adjusted model, men and women with Lp(a) levels below the 20th percentile had 217.3ml and 124.2ml less FEV1 and 239.0ml and 135.2ml less FVC, respectively, compared to participants with higher Lp(a) levels. The adjusted models also suggest that the known strong correlation between pro-inflammatory parameters and lung function has only a marginal impact on the Lp(a)-pulmonary function association. Our results do not support the hypothesis that higher Lp(a) levels are responsible for the increased CVD risk in people with reduced lung function, at least not in the group of community-dwelling older people studied here. PMID:26421427

  13. HOUSEHOLD PESTICIDE CONTAMINATION FROM INDOOR PEST CONTROL APPLICATIONS IN URBAN LOW-INCOME PUBLIC HOUSING DWELLINGS: A COMMUNITY-BASED PARTICIPATORY RESEARCH

    PubMed Central

    Adamkiewicz, Gary; Attfield, Kathleen; Kapp, Michaela; Spengler, John D; Tao, Lin; Xie, Shao Hua

    2013-01-01

    We designed this community-based participatory research (CBPR) project aiming to generate evidence-based research results in order to encourage residents living in urban low-income public housing dwellings engaging in a community-wide integrated pest management (IPM) program with the intention to improve their health and quality of life, as well as household conditions. We enrolled 20 families and their children in this study in which we utilized environmental exposure assessment (surface wipe and indoor air) tools to quantitatively assessing residential pesticide exposure in young children before the implementation of an IPM program. We analyzed those samples for 19 organophosphate (OP) and pyrethroid pesticides. The most commonly detected pesticides were pyrethroids, particularly permethrin and cypermethrin with average concentrations of 2.47 and 3.87 µg/m2, respectively. In many dwellings, we detected OPs, which are no longer available on the market, however, their levels are significantly lower than those of pyrethroids. None of the 20 families was free from pesticide contamination in their households, and pesticides were commonly detected in living room and children’s bedroom. The correlation among household hygienic conditions, the sighting of live pests/pest debris, and the degree of indoor pesticide contamination highlights the failure of conventional chemical-based applications for pest controls. The results from the current study, as well as other recent studies, conducted in low-income public housing, child care centers, and randomly selected homes in the U.S. should accentuate the need for alternative pest management programs that incorporate safer and more sustainable protocols for pest controls. PMID:23363037

  14. Household pesticide contamination from indoor pest control applications in urban low-income public housing dwellings: a community-based participatory research.

    PubMed

    Lu, Chensheng; Adamkiewicz, Gary; Attfield, Kathleen R; Kapp, Michaela; Spengler, John D; Tao, Lin; Xie, Shao Hua

    2013-02-19

    We designed this community-based participatory research (CBPR) project aiming to generate evidence-based research results to encourage residents living in urban low-income public housing dwellings engaging in a community-wide integrated pest management (IPM) program with the intention to improve their health and quality of life, as well as household conditions. We enrolled 20 families and their children in this study in which we utilized environmental exposure assessment (surface wipe and indoor air) tools to quantitatively assessing residential pesticide exposure in young children before the implementation of an IPM program. We analyzed those samples for 19 organophosphate (OP) and pyrethroid pesticides. The most commonly detected pesticides were pyrethroids, particularly permethrin and cypermethrin with average concentrations of 2.47 and 3.87 μg/m(2), respectively. In many dwellings, we detected OPs, which are no longer available on the market; however, their levels are significantly lower than those of pyrethroids. None of the 20 families was free from pesticide contamination in their households, and pesticides were commonly detected in living room and children's bedroom. The correlation among household hygienic conditions, the sighting of live pests/pest debris, and the degree of indoor pesticide contamination highlights the failure of conventional chemical-based applications for pest controls. The results from the current study, as well as other recent studies, conducted in low-income public housing, child care centers, and randomly selected homes in the U.S. should accentuate the need for alternative pest management programs that incorporate safer and more sustainable protocols for pest controls. PMID:23363037

  15. Prevalence, Work-Loss Days and Quality of Life of Community Dwelling Subjects with Depressive Symptoms

    PubMed Central

    Sohn, Jee Hoon; Ahn, Seung Hee; Seong, Su Jeong; Ryu, Ji Min

    2013-01-01

    The nationwide prevalence of major depressive disorder in Korea is lower than most countries, despite the high suicide rate. To explain this unexpectedly low prevalence, we examined the functional disability and quality of life in community-dwelling subjects with significant depressive symptoms not diagnosable as depressive disorder. A total of 1,029 subjects, randomly chosen from catchment areas, were interviewed with the Center for Epidemiologic Studies Depression scale, Mini International Neuropsychiatric Interview, WHO Quality of Life scale, and the WHO Disability Assessment Schedule. Those with scores over 21 on the depression scale were interviewed by a psychiatrist for diagnostic confirmation. Among community-dwelling subjects, the 1-month prevalence of major depressive disorder was 2.2%, but the 1-month prevalence of depressive symptoms not diagnosable as depressive disorder was 14.1%. Depressive disorders were the cause of 24.7% of work loss days, while depressive symptoms not diagnosable as depressive disorder were the cause of 17.2% of work loss days. These findings support the dimensional or spectrum approach to depressive disorder in the community and might be the missing link between the apparent low prevalence of depressive disorder and high suicide rate in Korea. PMID:23399785

  16. Exponential Sum-Fitting of Dwell-Time Distributions without Specifying Starting Parameters

    PubMed Central

    Landowne, David; Yuan, Bin; Magleby, Karl L.

    2013-01-01

    Fitting dwell-time distributions with sums of exponentials is widely used to characterize histograms of open- and closed-interval durations recorded from single ion channels, as well as for other physical phenomena. However, it can be difficult to identify the contributing exponential components. Here we extend previous methods of exponential sum-fitting to present a maximum-likelihood approach that consistently detects all significant exponentials without the need for user-specified starting parameters. Instead of searching for exponentials, the fitting starts with a very large number of initial exponentials with logarithmically spaced time constants, so that none are missed. Maximum-likelihood fitting then determines the areas of all the initial exponentials keeping the time constants fixed. In an iterative manner, with refitting after each step, the analysis then removes exponentials with negligible area and combines closely spaced adjacent exponentials, until only those exponentials that make significant contributions to the dwell-time distribution remain. There is no limit on the number of significant exponentials and no starting parameters need be specified. We demonstrate fully automated detection for both experimental and simulated data, as well as for classical exponential-sum-fitting problems. PMID:23746510

  17. Congruency analysis of biofilm-dwelling ciliates as a surrogate of eukaryotic microperiphyton for marine bioassessment.

    PubMed

    Xu, Guangjian; Wang, Zheng; Yang, Zhongwen; Xu, Henglong

    2015-12-30

    Biofilm-dwelling ciliates are primary components of the eukaryotic microperiphyton in both species composition and community structure. To evaluate the congruency of biofilm-dwelling ciliates as potential surrogates of the eukaryotic microperiphyton, a dataset was collected every month at four stations from the coastal waters of the Yellow Sea, northern China, and assessed. Sufficient species abundance data were obtained for ciliated protozoans at high taxonomic levels up to the family level, indicating a significant variation along the gradient of contamination. Correlation analyses revealed that the taxa richness of these matrices can explain > 85% of the variance in that of the full species dataset. The cost/benefit analysis showed that the protozoan subset at low resolutions up to the family level may be used as a potential surrogate of the original dataset. Thus, we suggest that the protozoan assemblages at genus- and/or family-level resolutions may be useful, cost-efficient surrogates of the original dataset for bioassessment in marine ecosystems. PMID:26507513

  18. Validation Analysis of a Geriatric Dehydration Screening Tool in Community-Dwelling and Institutionalized Elderly People

    PubMed Central

    Rodrigues, Susana; Silva, Joana; Severo, Milton; Inácio, Cátia; Padrão, Patrícia; Lopes, Carla; Carvalho, Joana; do Carmo, Isabel; Moreira, Pedro

    2015-01-01

    Dehydration is common among elderly people. The aim of this study was to perform validation analysis of a geriatric dehydration-screening tool (DST) in the assessment of hydration status in elderly people. This tool was based on the DST proposed by Vivanti et al., which is composed by 11 items (four physical signs of dehydration and seven questions about thirst sensation, pain and mobility), with four questions extra about drinking habits. The resulting questionnaire was evaluated in a convenience sample comprising institutionalized (n = 29) and community-dwelling (n = 74) elderly people. Urinary parameters were assessed (24-h urine osmolality and volume) and free water reserve (FWR) was calculated. Exploratory factor analysis was used to evaluate the scale’s dimensionality and Cronbach’s alpha was used to measure the reliability of each subscale. Construct’s validity was tested using linear regression to estimate the association between scores in each dimension and urinary parameters. Two factors emerged from factor analysis, which were named “Hydration Score” and “Pain Score”, and both subscales showed acceptable reliabilities. The “Hydration Score” was negatively associated with 24-h urine osmolality in community-dwelling; and the “Pain Score” was negatively associated with 24-h urine osmolality, and positively associated with 24-h urine volume and FWR in institutionalized elderly people. PMID:25739005

  19. Occurrence patterns of coral-dwelling gall crabs (Cryptochiridae) over depth intervals in the Caribbean.

    PubMed

    van Tienderen, Kaj M; van der Meij, Sancia E T

    2016-01-01

    Coral-associated invertebrates form a major part of the diversity on reefs, but their distribution and occurrence patterns are virtually unstudied. For associated taxa data are lacking on their distribution across shelves and environmental gradients, but also over various depths. Off Curaçao we studied the prevalence and density of coral-dwelling gall crabs (Cryptochiridae), obligate symbionts of stony corals. Belt transects (10 × 0.5m(2)) were laid out at 6, 12 and 18 m depth intervals at 27 localities. Twenty-one known host coral species were surveyed, measured, and the number of crab dwellings was recorded to study the influence of host occurrence, depth distribution, and colony size on the occurrence rates of three Atlantic gall crab species: Opecarcinus hypostegus, Troglocarcinus corallicola and Kroppcarcinus siderastreicola. The overall gall crab prevalence rate was 20.3% across all available host corals at all depths. The agariciid-associated species O. hypostegus was found to mostly inhabit Agaricia lamarcki and its prevalence was highest at deeper depths, following the depth distribution of its host. Kroppcarcinus siderastreicola, associated with Siderastrea and Stephanocoenia, inhabited shallower depths despite higher host availability at deeper depths. The generalist species T. corallicola showed no clear host or depth specialisation. These results show that the primary factors affecting the distribution and occurrence rates over depth intervals differed between each of the three Atlantic cryptochirid species, which in turn influences their vulnerability to reef degradation. PMID:26989629

  20. Use of biofilm-dwelling ciliate communities to determine environmental quality status of coastal waters.

    PubMed

    Xu, Henglong; Zhang, Wei; Jiang, Yong; Yang, Eun Jin

    2014-02-01

    It has increasingly been recognized that the ecological features of protozoan communities have many advantages as a favorable bioindicator to evaluate environmental stress and anthropogenic impact in many aquatic ecosystems. The ability of biofilm-dwelling ciliate communities for assessing environmental quality status was studied, using glass slides as an artificial substratum, during a 1-year cycle (August 2011-July 2012) in coastal waters of the Yellow Sea, northern China. The samples were collected monthly at a depth of 1m from four sampling stations with a spatial gradient of environmental stress. Environmental variables, e.g., salinity, dissolved oxygen (DO), chemical oxygen demand (COD), nitrate nitrogen (NO3-N), ammonium nitrogen (NH4-N) and soluble reactive phosphates (SRP), were measured synchronously for comparison with biotic parameters. Results showed that: (1) the community structures of the ciliates represented significant differences among the four sampling stations; (2) spatial patterns of the ciliate communities were significantly correlated with environmental variables, especially COD and the nutrients; (3) five dominant species (Hartmannula angustipilosa, Metaurostylopsis sp.1, Discocephalus ehrenbergi, Stephanopogon minuta and Pseudovorticella paracratera) were significantly correlated with nutrients or COD; and (4) the species richness measure was significantly correlated with the nutrient NO3-N. It is suggested that biofilm-dwelling ciliate communities might be used as a potentially robust bioindicator for discriminating environmental quality status in coastal waters. PMID:24176698