Science.gov

Sample records for 5-10 cm soil

  1. Estimation of CO2 diffusion coefficient at 0-10 cm depth in undisturbed and tilled soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diffusion coefficients (D) of CO2 at 0 – 10 cm layers in undisturbed and tilled soil conditions were estimated using Penman, Millington-Quirk, Ridgwell et al. (1999), Troeh et al., and Moldrup et al. models. Soil bulk density and volumetric soil water content ('v) at 0 – 10 cm were measured on April...

  2. Biocrusts serve as biomarkers for the upper 30 cm soil water content

    NASA Astrophysics Data System (ADS)

    Kidron, Giora J.; Benenson, Itzhak

    2014-02-01

    Knowledge regarding the spatial distribution of moisture in soil is of great importance especially in arid regions where water is scarce. Following a previous research that showed a significant relationship between daylight surface wetness duration and the average chlorophyll content of 5 biocrusts in the Negev Desert (Israel), and the resultant outcome that pointed to the possible use of biocrusts as biomarkers for surface wetness duration, we hypothesize that biocrusts may also serve as biomarkers for the moisture content of the upper soil layer. Toward this end, daylight surface wetness duration was measured at 5 crust types following rain events during 1993-1995 along with periodical soil sampling of the upper 30 cm (at 5 cm intervals) of the soil profiles underlying these biocrusts. The findings showed a positive linear relationship between daylight surface wetness duration and the chlorophyll content of the crusts (r2 = 0.96-0.97). High correlations were also found between daylight surface wetness duration and the available water content (r2 = 0.96) and duration (r2 = 0.85-0.88) of the upper 30 cm soil and between the chlorophyll content of the crust and the available water content (r2 = 0.93-0.96) and duration (r2 = 0.78-0.84). Topography-induced shading and slope position (which determined additional water either by runoff or subsurface flow) are seen responsible for the clear link between subsurface moisture content, daylight surface wetness duration and chlorophyll content of the crust. This link points to the possible use of biocrusts as biomarkers for subsurface water content and highlights the importance of crust typology and mapping for the study of the spatial distribution of water and their potential use for the study of ecosystem structure and function.

  3. A case study demonstration of the soil temperature extrema recovery rates after precipitation cooling at 10-cm soil depth

    NASA Technical Reports Server (NTRS)

    Welker, Jean Edward

    1991-01-01

    Since the invention of maximum and minimum thermometers in the 18th century, diurnal temperature extrema have been taken for air worldwide. At some stations, these extrema temperatures were collected at various soil depths also, and the behavior of these temperatures at a 10-cm depth at the Tifton Experimental Station in Georgia is presented. After a precipitation cooling event, the diurnal temperature maxima drop to a minimum value and then start a recovery to higher values (similar to thermal inertia). This recovery represents a measure of response to heating as a function of soil moisture and soil property. Eight different curves were fitted to a wide variety of data sets for different stations and years, and both power and exponential curves were fitted to a wide variety of data sets for different stations and years. Both power and exponential curve fits were consistently found to be statistically accurate least-square fit representations of the raw data recovery values. The predictive procedures used here were multivariate regression analyses, which are applicable to soils at a variety of depths besides the 10-cm depth presented.

  4. Effects of modified soil water-heat physics on RegCM4 simulations of climate over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Wang, Xuejia; Pang, Guojin; Yang, Meixue; Wan, Guoning

    2016-06-01

    To optimize the description of land surface processes and improve climate simulations over the Tibetan Plateau (TP), a modified soil water-heat parameterization scheme (SWHPS) is implemented into the Community Land Model 3.5 (CLM3.5), which is coupled to the regional climate model 4 (RegCM4). This scheme includes Johansen's soil thermal conductivity scheme together with Niu's groundwater module. Two groups of climate simulations are then performed using the original RegCM4 and revised RegCM4 to analyze the effects of the revised SWHPS on regional climate simulations. The effect of the revised RegCM4 on simulated air temperature is relatively small (with mean biases changing by less than 0.1°C over the TP). There are overall improvements in the simulation of winter and summer air temperature but increased errors in the eastern TP. It has a significant effect on simulated precipitation. There is also a clear improvement in simulated annual and winter precipitation, particularly over the northern TP, including the Qilian Mountains and the source region of the Yellow River. There are, however, increased errors in precipitation simulation in parts of the southern TP. The precipitation difference between the two models is caused mainly by their convective precipitation difference, particularly in summer. Overall, the implementation of the new SWHPS into the RegCM4 has a significant effect not only on land surface variables but also on the overlying atmosphere through various physical interactions.

  5. Thermal emission measurements 2000-400/cm (5-25 micrometers) of Hawaiian palagonitic soils and their implications for Mars

    NASA Technical Reports Server (NTRS)

    Roush, Ted L.; Bell, James F., III

    1995-01-01

    The thermal emision of two palagonitic soils, common visible and near infrared spectral analogs for bright soils on Mars, was measured over the wavelength range of 5 to 25 micrometers (2000 to 400/cm) for several partical size separates. All spectra exhibit emissivity features due to vibrations associated with H2O and SiO. The maximum variability of emissivity is approximately 20% in the short wavelength region (5 to 6.5 mirometers, 2000 to 1500/cm), and is more subdued, less than 4%, at longer wavelengths. The strengths of features present in the infrared spectra of Mars cannot be solely provided by emissivity variations of palagonite; some other material or mechanism must provide additional absorptions(s).

  6. Assessing potential of vertical average soil moisture (0-40cm) estimation for drought monitoring using MODIS data: a case study

    NASA Astrophysics Data System (ADS)

    Ma, Jianwei; Huang, Shifeng; Li, Jiren; Li, Xiaotao; Song, Xiaoning; Leng, Pei; Sun, Yayong

    2015-12-01

    Soil moisture is an important parameter in the research of hydrology, agriculture, and meteorology. The present study is designed to produce a near real time soil moisture estimation algorithm by linking optical/IR measurements to ground measured soil moisture, and then used to monitoring region drought. It has been found that the Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST) are related to surface soil moisture. Therefore, a relationship between ground measurement soil moisture and NDVI and LST can be developed. Six days' NDVI and LST data calculated from Terra Moderate Resolution Imaging Spectroradiometer (MODIS) of Shandong province during October in 2009 to May in 2010 were combined with ground measured volumetric soil moisture in different depth (10cm, 20cm, 40cm, and mean in vertical (0-40cm)) and different soil type to determine regression relationships at a 1 km scale. Based on the regression relationships, mean volumetric soil moisture in vertical (0-40cm) at 1 km resolution can be calculated over the Shandong province, and then drought maps were obtained. The result shows that significantly relationship exists between the NDVI and LST and soil moisture at different soil depths, and regression relationships are soil type dependent. What is more, the drought monitoring results agree well with actual situation.

  7. Thermal emission measurements 2000-400 cm(exp -1) (5-25 microns) of Hawaiian palagonitic soils and their implications for Mars

    NASA Technical Reports Server (NTRS)

    Roush, Ted L.; Bell, James F., III

    1995-01-01

    The thermal emission of two palagonitic soils, common visible and near infrared spectral analogs for bright soils on Mars, was measured over the wavelength range of 5 to 25 microns (2000 to 400 cm(exp -1) for several particle size separates. All spectra exhibit emissivity features due to vibrations associated with H2O and SiO. The maximum variability of emissivity is approx. = 20% in the short wavelength region (5 to 6.5 microns, 2000 to 1500 cm(exp -1)), and is more subdued, < 4%, at longer wavelengths. The strengths of features present in infrared spectra of Mars cannot be solely provided by emissivity variations of palagonite; some other material or mechanism must provide additional absorption(s).

  8. 1 CFR 5.10 - Forms of publication.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 1 General Provisions 1 2013-01-01 2012-01-01 true Forms of publication. 5.10 Section 5.10 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER THE FEDERAL REGISTER GENERAL § 5.10 Forms of publication. Pursuant to section 1506 of title 44, United States Code, the Administrative Committee...

  9. 1 CFR 5.10 - Forms of publication.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 1 General Provisions 1 2014-01-01 2012-01-01 true Forms of publication. 5.10 Section 5.10 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER THE FEDERAL REGISTER GENERAL § 5.10 Forms of publication. Pursuant to section 1506 of title 44, United States Code, the Administrative Committee...

  10. 1 CFR 5.10 - Forms of publication.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 1 General Provisions 1 2012-01-01 2012-01-01 false Forms of publication. 5.10 Section 5.10 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER THE FEDERAL REGISTER GENERAL § 5.10 Forms of publication. Pursuant to section 1506 of title 44, United States Code, the Administrative Committee...

  11. 34 CFR 5.10 - Public reading room.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 1 2014-07-01 2014-07-01 false Public reading room. 5.10 Section 5.10 Education Office... Available to the Public § 5.10 Public reading room. (a) General. Pursuant to 5 U.S.C. 552(a)(2), the Department maintains a public reading room containing agency records that the FOIA requires to be...

  12. 34 CFR 5.10 - Public reading room.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 1 2012-07-01 2012-07-01 false Public reading room. 5.10 Section 5.10 Education Office... Available to the Public § 5.10 Public reading room. (a) General. Pursuant to 5 U.S.C. 552(a)(2), the Department maintains a public reading room containing agency records that the FOIA requires to be...

  13. 34 CFR 5.10 - Public reading room.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 34 Education 1 2013-07-01 2013-07-01 false Public reading room. 5.10 Section 5.10 Education Office... Available to the Public § 5.10 Public reading room. (a) General. Pursuant to 5 U.S.C. 552(a)(2), the Department maintains a public reading room containing agency records that the FOIA requires to be...

  14. 34 CFR 5.10 - Public reading room.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 1 2011-07-01 2011-07-01 false Public reading room. 5.10 Section 5.10 Education Office... Available to the Public § 5.10 Public reading room. (a) General. Pursuant to 5 U.S.C. 552(a)(2), the Department maintains a public reading room containing agency records that the FOIA requires to be...

  15. 36 CFR 5.10 - Eating, drinking, or lodging establishments.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Eating, drinking, or lodging establishments. 5.10 Section 5.10 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR COMMERCIAL AND PRIVATE OPERATIONS § 5.10 Eating, drinking, or lodging establishments. (a)...

  16. 36 CFR 5.10 - Eating, drinking, or lodging establishments.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Eating, drinking, or lodging establishments. 5.10 Section 5.10 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR COMMERCIAL AND PRIVATE OPERATIONS § 5.10 Eating, drinking, or lodging establishments. (a)...

  17. 6 CFR 5.10 - Preservation of records.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 6 Domestic Security 1 2010-01-01 2010-01-01 false Preservation of records. 5.10 Section 5.10 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY DISCLOSURE OF RECORDS AND INFORMATION Freedom of Information Act § 5.10 Preservation of records. Each component shall preserve...

  18. 1 CFR 5.10 - Forms of publication.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 1 General Provisions 1 2010-01-01 2010-01-01 false Forms of publication. 5.10 Section 5.10 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER THE FEDERAL REGISTER GENERAL § 5.10 Forms of publication. Pursuant to section 1506 of title 44, United States Code, the Administrative Committee...

  19. 1 CFR 5.10 - Forms of publication.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 1 General Provisions 1 2011-01-01 2011-01-01 false Forms of publication. 5.10 Section 5.10 General Provisions ADMINISTRATIVE COMMITTEE OF THE FEDERAL REGISTER THE FEDERAL REGISTER GENERAL § 5.10 Forms of publication. Pursuant to section 1506 of title 44, United States Code, the Administrative Committee...

  20. A CM chondrite cluster and CM streams

    NASA Technical Reports Server (NTRS)

    Dodd, R. T.; Lipschutz, M. E.

    1993-01-01

    An elongate year-day concentration of CM meteoroid falls between 1921 and 1969 is inconsistent with a random flux of CM meteoroids and suggests that most or all such meteorites, and perhaps the Kaidun C-E chondrite breccia, resulted from streams of meteoroids in nearly circular, Earth-like orbits. To establish whether the post-1920 cluster might have arisen from random sampling, we determined the year-day distribution of 14 falls between 1879 and 1969 by treating each as the corner of a cell of specified dimensions (e.g. 30 years x 30 days) and calculated how many falls occurred in that cell. We then compared the CM cell distribution with random distributions over the same range of years. The results show that for 30 x 30 and 45 x 45 cells, fewer than 5 percent of random sets match the CM distribution with respect to maximum cell content and number of one-fall cells.

  1. 36 CFR 5.10 - Eating, drinking, or lodging establishments.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., Rocky Mountain, Sequoia-Kings Canyon, Yellowstone, and Yosemite National Parks may be operated without a... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Eating, drinking, or lodging establishments. 5.10 Section 5.10 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF...

  2. Chernobyl fallout in the uppermost (0-3 cm) humus layer of forest soil in Finland, North East Russia and the Baltic countries in 2000--2003.

    PubMed

    Ylipieti, J; Rissanen, K; Kostiainen, E; Salminen, R; Tomilina, O; Täht, K; Gilucis, A; Gregorauskiene, V

    2008-12-15

    The situation resulting from the Chernobyl fallout in 1987 was compared to that in 2000--2001 in Finland and NW Russia and that in 2003 in the Baltic countries. 786 humus (0-3 cm layer) samples were collected during 2000--2001 in the Barents Ecogeochemistry Project, and 177 samples in the Baltic countries in 2003. Nuclides emitting gamma-radiation in the 0-3 cm humus layer were measured by the Radiation and Nuclear Safety Authority-STUK in Finland. In 1987 the project area was classified by the European Commission into four different fallout classes. 137Cs inventory Bg/m2 levels measured in 2000--2003 were compared to the EU's class ranges. Fitting over the whole project area was implemented by generalizing the results for samples from the Baltic countries, for which Bq/m2 inventories could be calculated. A rough estimation was made by comparing the mass of organic matter and humus with 137Cs concentrations in these two areas. Changes in 137Cs concentration levels are illustrated in both thematic maps and tables. Radionuclide 137Cs concentrations (Bq/kg d.w.) were detected in the humus layer at all the 988 sampling sites. 134Cs was still present in 198 sites 15 years after the nuclear accident in Chernobyl. No other anthropogenic nuclides emitting gamma-radiation were detected, but low levels of 60Co, 125Sb and 154Eu isotopes were found in 14 sites. Fifteen years after the Chernobyl accident, the radioactive nuclide 137Cs was and still is the most significant fallout radionuclide in the environment and in food chains. The results show that the fallout can still be detected in the uppermost humus layer in North East Europe.

  3. 30 CFR 5.10 - Purpose and scope.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... MINING PRODUCTS FEES FOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS § 5.10 Purpose and scope... proportionate share of management, administration and operation of the Approval and Certification Center...

  4. Ubiquitous CM and DM

    NASA Technical Reports Server (NTRS)

    Crowley, Sandra L.

    2000-01-01

    Ubiquitous is a real word. I thank a former Total Quality Coach for my first exposure some years ago to its existence. My version of Webster's dictionary defines ubiquitous as "present, or seeming to be present, everywhere at the same time; omnipresent." While I believe that God is omnipresent, I have come to discover that CM and DM are present everywhere. Oh, yes; I define CM as Configuration Management and DM as either Data or Document Management. Ten years ago, I had my first introduction to the CM world. I had an opportunity to do CM for the Space Station effort at the NASA Lewis Research Center. I learned that CM was a discipline that had four areas of focus: identification, control, status accounting, and verification. I was certified as a CMIl graduate and was indoctrinated about clear, concise, and valid. Off I went into a world of entirely new experiences. I was exposed to change requests and change boards first hand. I also learned about implementation of changes, and then of technical and CM requirements.

  5. Halogens in CM Chondrites

    NASA Astrophysics Data System (ADS)

    Menard, J. M.; Caron, B.; Jambon, A.; Michel, A.; Villemant, B.

    2013-09-01

    We set up an extraction line of halogens (fluorine, chlorine) by pyrohydrolysis with 50 mg of rock. We analyzed 7 CM2 chondrites found in Antarctica and found that the Cl content of meteorites with an intact fusion crust is higher than those without.

  6. 30 CFR 5.10 - Purpose and scope.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS FEES FOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS § 5.10 Purpose and scope... (investigators), including administrative review of applications, analysis of drawings, technical...

  7. 30 CFR 5.10 - Purpose and scope.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS FEES FOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS § 5.10 Purpose and scope... (investigators), including administrative review of applications, analysis of drawings, technical...

  8. 36 CFR 5.10 - Eating, drinking, or lodging establishments.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Eating, drinking, or lodging... INTERIOR COMMERCIAL AND PRIVATE OPERATIONS § 5.10 Eating, drinking, or lodging establishments. (a) No establishment offering food, drink, or lodging for sale on any privately owned lands under the...

  9. 36 CFR 5.10 - Eating, drinking, or lodging establishments.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Eating, drinking, or lodging... INTERIOR COMMERCIAL AND PRIVATE OPERATIONS § 5.10 Eating, drinking, or lodging establishments. (a) No establishment offering food, drink, or lodging for sale on any privately owned lands under the...

  10. [Seasonal dynamics of soil organic carbon mineralization for two forest types in Xiaoxing'an Mountains, China].

    PubMed

    Gao, Fei; Lin, Wei; Cui, Xiao-yang

    2016-01-01

    To investigate the seasonal dynamics of soil organic carbon (SOC) mineralization in Xiaoxing'an Mountain, we incubated soil samples collected from virgin Korean pine forest and broad-leaved secondary forest in different seasons in the laboratory and measured the SOC mineralization rate and cumulative SOC mineralization (Cm). We employed simultaneous reaction model to describe C mineralization kinetics and estimated SOC mineralization parameters including soil easily mineralizable C (C1), potentially mineralizable C (C₀). We also analyzed the relations between Cm, C₁and their influencing factors. Results showed that the incubated SOC mineralization rate and Cm for 0-5 cm soil layer decreased from early spring to late autumn, while for 5-10 cm soil layer the seasonal variation was not statistically significant for both forest types. The C₁ in 0-5 and 5-10 cm soil layers varied from 42.92-92.18 and 19.23-32.95 mg kg⁻¹, respectively, while the C₀ in 0-5 and 5-10 cm soil layers varied from 863.92-3957.15 and 434.15-865.79 mg · kg⁻¹, respec- tively. Both C₁ and C₀ decreased from early spring to late autumn. The proportions of C₀ in SOC for two forest types were 0.74%-2.78% and 1.11%-1.84% in 0-5 and 5-10 cm soil layers, respectively, and decreased from early spring to late autumn, indicating that SOC tended to become more stable as a whole from spring to autumn. The Cm and C₀ were significantly positively correlated to in situ soil water content and hot water-extractable carbohydrate content, but were not correlated to in situ soil temperature and cool water-extractable carbohydrate content. We concluded that soil labile organic carbon, soil physical and chemical properties contributed to the seasonal dynamics of SOC mineralization in the forests.

  11. [Seasonal dynamics of soil organic carbon mineralization for two forest types in Xiaoxing'an Mountains, China].

    PubMed

    Gao, Fei; Lin, Wei; Cui, Xiao-yang

    2016-01-01

    To investigate the seasonal dynamics of soil organic carbon (SOC) mineralization in Xiaoxing'an Mountain, we incubated soil samples collected from virgin Korean pine forest and broad-leaved secondary forest in different seasons in the laboratory and measured the SOC mineralization rate and cumulative SOC mineralization (Cm). We employed simultaneous reaction model to describe C mineralization kinetics and estimated SOC mineralization parameters including soil easily mineralizable C (C1), potentially mineralizable C (C₀). We also analyzed the relations between Cm, C₁and their influencing factors. Results showed that the incubated SOC mineralization rate and Cm for 0-5 cm soil layer decreased from early spring to late autumn, while for 5-10 cm soil layer the seasonal variation was not statistically significant for both forest types. The C₁ in 0-5 and 5-10 cm soil layers varied from 42.92-92.18 and 19.23-32.95 mg kg⁻¹, respectively, while the C₀ in 0-5 and 5-10 cm soil layers varied from 863.92-3957.15 and 434.15-865.79 mg · kg⁻¹, respec- tively. Both C₁ and C₀ decreased from early spring to late autumn. The proportions of C₀ in SOC for two forest types were 0.74%-2.78% and 1.11%-1.84% in 0-5 and 5-10 cm soil layers, respectively, and decreased from early spring to late autumn, indicating that SOC tended to become more stable as a whole from spring to autumn. The Cm and C₀ were significantly positively correlated to in situ soil water content and hot water-extractable carbohydrate content, but were not correlated to in situ soil temperature and cool water-extractable carbohydrate content. We concluded that soil labile organic carbon, soil physical and chemical properties contributed to the seasonal dynamics of SOC mineralization in the forests. PMID:27228587

  12. PAH-concentrations and compositions in the top 2 cm of forest soils along a 120 km long transect through agricultural areas, forests and the city of Oslo, Norway.

    PubMed

    Jensen, Henning; Reimann, Clemens; Finne, Tor Erik; Ottesen, Rolf Tore; Arnoldussen, Arnold

    2007-02-01

    The top 2 cm of forest soils were collected along a 120 km long south-north transect running through Norway's largest city Oslo. Forty samples were analysed for their polycyclic aromatic hydrocarbon (PAH(16) as defined by the U.S. Environmental Protection Agency) concentrations and compositions. Local variations in the PAH values are high and the reported concentrations are in general low (maximum sumPAH16: 2.6 mg/kg). The transect shows distinct differences of sumPAH16 values from south to north. PAH concentrations are substantially lower in the less populated areas at the north end of the transect than at the urbanised and much more populated south end. Several high values occur in a forested area to the north of Oslo, used for recreation purposes. The PAH distribution patterns point towards a predominantly pyrogenic origin. Local Cambrian carbon-rich black shales can be excluded as sources for PAHs in the forest soils. PMID:16787690

  13. A simple procedure for estimating soil porosity

    NASA Astrophysics Data System (ADS)

    Emmet-Booth, Jeremy; Forristal, Dermot; Fenton, Owen; Holden, Nick

    2016-04-01

    Soil degradation from mismanagement is of international concern. Simple, accessible tools for rapidly assessing impacts of soil management are required. Soil structure is a key component of soil quality and porosity is a useful indicator of structure. We outline a version of a procedure described by Piwowarczyk et al. (2011) used to estimate porosity of samples taken during a soil quality survey of 38 sites across Ireland as part of the Government funded SQUARE (Soil Quality Assessment Research) project. This required intact core (r = 2.5 cm, H = 5cm) samples taken at 5-10 cm and 10-20 cm depth, to be covered with muslin cloth at one end and secured with a jubilee clip. Samples were saturated in sealable water tanks for ≈ 64 hours, then allowed to drain by gravity for 24 hours, at which point Field Capacity (F.C.) was assumed to have been reached, followed by oven drying with weight determined at each stage. This allowed the calculation of bulk density and the estimation of water content at saturation and following gravitational drainage, thus total and functional porosity. The assumption that F.C. was reached following 24 hours of gravitational drainage was based on the Soil Moisture Deficit model used in Ireland to predict when soils are potentially vulnerable to structural damage and used nationally as a management tool. Preliminary results indicate moderately strong, negative correlations between estimated total porosity at 5-10 cm and 10-20 cm depth (rs = -0.7, P < 0.01 in both cases) and soil quality scores of the Visual Evaluation of Soil Structure (VESS) method which was conducted at each survey site. Estimated functional porosity at 5-10 cm depth was found to moderately, negatively correlate with VESS scores (rs = - 0.5, P < 0.05). This simple procedure requires inexpensive equipment and appears useful in indicating porosity of a large quantity of samples taken at numerous sites or if done periodically, temporal changes in porosity at a field scale

  14. BROWN DWARF DISKS AT AGES OF 5-10 Myr

    SciTech Connect

    Riaz, Basmah; Lodieu, Nicolas; Gizis, John E.

    2009-11-01

    We present Spitzer/IRAC and MIPS 24 mum observations for 28 brown dwarfs in the Upper Scorpius (UppSco) region. We find a disk fraction of 10.7%{sup +8.7%} {sub -3.3%}. One object shows a small excess at 24 mum but none at shorter wavelengths, and may be a candidate transition disk. Three objects show emission in the 10 mum silicate feature and we present compositional fits for these sources. Flat structures are observed for all disk sources in UppSco. Also presented are the MIPS/70 mum observations for the TW Hydrae Association brown dwarf 2MASS J1139511-315921. We discuss the structure and chemistry of brown dwarf disks at ages of approx5-10 Myr, and consider the possible effects of the brown dwarf densities in these clusters on the disk lifetimes.

  15. β-Nitro-5,10,15-tritolylcorroles

    PubMed Central

    Stefanelli, Manuela; Pomarico, Giuseppe; Tortora, Luca; Nardis, Sara; Fronczek, Frank R.; McCandless, Gregory T.; Smith, Kevin M.; Manowong, Machima; Chen, Ping; Kadish, Karl M.; Rosa, Angela; Ricciardi, Giampaolo; Paolesse, Roberto

    2012-01-01

    Functionalization of the β-pyrrolic positions of the corrole macrocycle with –NO2 groups is limited at present to metallocorrolates due to of the instability exhibited by corrole free bases under oxidizing conditions. A careful choice of the oxidant can limit the transformation of corroles into decomposition products or isocorrole species, preserving the corrole aromaticity, and thus allowing the insertion of nitro groups onto the corrole framework. Here we report results obtained by reacting 5,10,15-tritolylcorrole (TTCorrH3) with the AgNO2/NaNO2 system, to give mono- and di-nitrocorrole derivatives when stoichiometry is carefully controlled. Reactions were found to be regioselective, affording the 3-NO2TTCorrH3 and 3,17-(NO2)2TTCorrH3 isomers as the main products in the case of mono- and di-substitution, in 53 and 20% yields, respectively. In both cases, traces of other mono- and di-substituted isomers were detected, which were structurally characterized by X-ray crystallography. The influence of the β-nitro substituents on the corrole properties is studied in detail by UV-visible, electrochemical, and spectroelectrochemical characterization of these functionalized corroles. Density Functional Theory (DFT) and time-dependent DFT (TDDFT) calculations of the ground and excited state properties of these β-nitrocorrole derivatives also afforded significant information, closely matching the experimental observations. It is found that the β-NO2 substituents conjugate with the π-aromatic system of the macrocycle, which initiates significant changes in both the spectroscopic and redox properties of the so functionalized corroles. This effect is more pronounced when the nitro group is introduced at the 2-position, because in this case the conjugation is, for steric reasons, more efficient than in the 3-nitro isomer. PMID:22668242

  16. Depth-Dependent Mineral Soil CO2 Production Processes: Sensitivity to Harvesting-Induced Changes in Soil Climate.

    PubMed

    Kellman, Lisa; Myette, Amy; Beltrami, Hugo

    2015-01-01

    Forest harvesting induces a step change in the climatic variables (temperature and moisture), that control carbon dioxide (CO2) production arising from soil organic matter decomposition within soils. Efforts to examine these vertically complex relationships in situ within soil profiles are lacking. In this study we examined how the climatic controls on CO2 production change within vertically distinct layers of the soil profile in intact and clearcut forest soils of a humid temperate forest system of Atlantic Canada. We measured mineral soil temperature (0, 5, 10, 20, 50 and 100 cm depth) and moisture (0-15 cm and 30-60 cm depth), along with CO2 surface efflux and subsurface concentrations (0, 2.5, 5, 10, 20, 35, 50, 75 and 100 cm depth) in 1 m deep soil pits at 4 sites represented by two forest-clearcut pairs over a complete annual cycle. We examined relationships between surface efflux at each site, and soil heat, moisture, and mineral soil CO2 production. Following clearcut harvesting we observed increases in temperature through depth (1-2°C annually; often in excess of 4°C in summer and spring), alongside increases in soil moisture (30%). We observed a systematic breakdown in the expected exponential relationship between CO2 production and heat with mineral soil depth, consistent with an increase in the role moisture plays in constraining CO2 production. These findings should be considered in efforts to model and characterize mineral soil organic matter decomposition in harvested forest soils. PMID:26263510

  17. Depth-Dependent Mineral Soil CO2 Production Processes: Sensitivity to Harvesting-Induced Changes in Soil Climate

    PubMed Central

    Kellman, Lisa; Myette, Amy; Beltrami, Hugo

    2015-01-01

    Forest harvesting induces a step change in the climatic variables (temperature and moisture), that control carbon dioxide (CO2) production arising from soil organic matter decomposition within soils. Efforts to examine these vertically complex relationships in situ within soil profiles are lacking. In this study we examined how the climatic controls on CO2 production change within vertically distinct layers of the soil profile in intact and clearcut forest soils of a humid temperate forest system of Atlantic Canada. We measured mineral soil temperature (0, 5, 10, 20, 50 and 100 cm depth) and moisture (0–15 cm and 30–60 cm depth), along with CO2 surface efflux and subsurface concentrations (0, 2.5, 5, 10, 20, 35, 50, 75 and 100 cm depth) in 1 m deep soil pits at 4 sites represented by two forest-clearcut pairs over a complete annual cycle. We examined relationships between surface efflux at each site, and soil heat, moisture, and mineral soil CO2 production. Following clearcut harvesting we observed increases in temperature through depth (1–2°C annually; often in excess of 4°C in summer and spring), alongside increases in soil moisture (30%). We observed a systematic breakdown in the expected exponential relationship between CO2 production and heat with mineral soil depth, consistent with an increase in the role moisture plays in constraining CO2 production. These findings should be considered in efforts to model and characterize mineral soil organic matter decomposition in harvested forest soils. PMID:26263510

  18. THE METALLICITY OF THE CM DRACONIS SYSTEM

    SciTech Connect

    Terrien, Ryan C.; Fleming, Scott W.; Mahadevan, Suvrath; Deshpande, Rohit; Bender, Chad F.; Ramsey, Lawrence W.; Feiden, Gregory A.

    2012-11-20

    The CM Draconis system comprises two eclipsing mid-M dwarfs of nearly equal mass in a 1.27 day orbit. This well-studied eclipsing binary has often been used for benchmark tests of stellar models, since its components are among the lowest mass stars with well-measured masses and radii ({approx}< 1% relative precision). However, as with many other low-mass stars, non-magnetic models have been unable to match the observed radii and effective temperatures for CM Dra at the 5%-10% level. To date, the uncertain metallicity of the system has complicated comparison of theoretical isochrones with observations. In this Letter, we use data from the SpeX instrument on the NASA Infrared Telescope Facility to measure the metallicity of the system during primary and secondary eclipses, as well as out of eclipse, based on an empirical metallicity calibration in the H and K near-infrared (NIR) bands. We derive an [Fe/H] = -0.30 {+-} 0.12 that is consistent across all orbital phases. The determination of [Fe/H] for this system constrains a key dimension of parameter space when attempting to reconcile model isochrone predictions and observations.

  19. The Metallicity of the CM Draconis System

    NASA Astrophysics Data System (ADS)

    Terrien, Ryan C.; Fleming, Scott W.; Mahadevan, Suvrath; Deshpande, Rohit; Feiden, Gregory A.; Bender, Chad F.; Ramsey, Lawrence W.

    2012-11-01

    The CM Draconis system comprises two eclipsing mid-M dwarfs of nearly equal mass in a 1.27 day orbit. This well-studied eclipsing binary has often been used for benchmark tests of stellar models, since its components are among the lowest mass stars with well-measured masses and radii (lsim 1% relative precision). However, as with many other low-mass stars, non-magnetic models have been unable to match the observed radii and effective temperatures for CM Dra at the 5%-10% level. To date, the uncertain metallicity of the system has complicated comparison of theoretical isochrones with observations. In this Letter, we use data from the SpeX instrument on the NASA Infrared Telescope Facility to measure the metallicity of the system during primary and secondary eclipses, as well as out of eclipse, based on an empirical metallicity calibration in the H and K near-infrared (NIR) bands. We derive an [Fe/H] = -0.30 ± 0.12 that is consistent across all orbital phases. The determination of [Fe/H] for this system constrains a key dimension of parameter space when attempting to reconcile model isochrone predictions and observations.

  20. Serpentine Nanotubes in CM Chondrites

    NASA Technical Reports Server (NTRS)

    Zega, Thomas J.; Garvie, Laurence A. J.; Dodony, Istvan; Buseck, Peter R.

    2004-01-01

    The CM chondrites are primitive meteorites that formed during the early solar system. Although they retain much of their original physical character, their matrices and fine-grained rims (FGRs) sustained aqueous alteration early in their histories [1- 3]. Serpentine-group minerals are abundant products of such alteration, and information regarding their structures, compositions, and spatial relationships is important for determining the reactions that produced them and the conditions under which they formed. Our recent work on FGRs and matrices of the CM chondrites has revealed new information on the structures and compositions of serpentine-group minerals [4,5] and has provided insights into the evolution of these primitive meteorites. Here we report on serpentine nanotubes from the Mighei and Murchison CM chondrites [6].

  1. 344 cm x 86 cm low mass vacuum window

    SciTech Connect

    Reimers, R.M.; Porter, J.; Meneghetti, J.; Wilde, S.; Miller, R.

    1983-08-01

    The LBL Heavy Ion Spectrometer System (HISS) superconducting magnet contains a 1 m x 3.45 m x 2 m vacuum tank in its gap. A full aperture thin window was needed to minimize background as the products of nuclear collisions move from upstream targets to downstream detectors. Six windows were built and tested in the development process. The final window's unsupported area is 3m/sup 2/ with a 25 cm inward deflection. The design consists of a .11 mm Nylon/aluminum/polypropylene laminate as a gas seal and .55 mm woven aramid fiber for strength. Total mass is 80 milligrams per cm/sup 2/. Development depended heavily on past experience and testing. Safety considerations are discussed.

  2. Global distribution of plant-extractable water capacity of soil

    USGS Publications Warehouse

    Dunne, K.A.; Willmott, C.J.

    1996-01-01

    Plant-extractable water capacity of soil is the amount of water that can be extracted from the soil to fulfill evapotranspiration demands. It is often assumed to be spatially invariant in large-scale computations of the soil-water balance. Empirical evidence, however, suggests that this assumption is incorrect. In this paper, we estimate the global distribution of the plant-extractable water capacity of soil. A representative soil profile, characterized by horizon (layer) particle size data and thickness, was created for each soil unit mapped by FAO (Food and Agriculture Organization of the United Nations)/Unesco. Soil organic matter was estimated empirically from climate data. Plant rooting depths and ground coverages were obtained from a vegetation characteristic data set. At each 0.5?? ?? 0.5?? grid cell where vegetation is present, unit available water capacity (cm water per cm soil) was estimated from the sand, clay, and organic content of each profile horizon, and integrated over horizon thickness. Summation of the integrated values over the lesser of profile depth and root depth produced an estimate of the plant-extractable water capacity of soil. The global average of the estimated plant-extractable water capacities of soil is 8??6 cm (Greenland, Antarctica and bare soil areas excluded). Estimates are less than 5, 10 and 15 cm - over approximately 30, 60, and 89 per cent of the area, respectively. Estimates reflect the combined effects of soil texture, soil organic content, and plant root depth or profile depth. The most influential and uncertain parameter is the depth over which the plant-extractable water capacity of soil is computed, which is usually limited by root depth. Soil texture exerts a lesser, but still substantial, influence. Organic content, except where concentrations are very high, has relatively little effect.

  3. Global Distribution of Plant-Extractable Water Capacity of Soil

    NASA Astrophysics Data System (ADS)

    Dunne, K. A.; Willmott, Cort J.

    1996-08-01

    Plant-extractable water capacity of soil is the amount of water that can be extracted from the soil to fulfill evapotranspiration demands. It is often assumed to be spatially invariant in large-scale computations of the soil-water balance. Empirical evidence, however, suggests that this assumption is incorrect. In this paper, we estimate the global distribution of the plant-extractable water capacity of soil.A representative soil profile, characterized by horizon (layer) particle size data and thickness, was created for each soil unit mapped by FAO (Food and Agriculture Organization of the United Nations)/Unesco. Soil organic matter was estimated empirically from climate data. Plant rooting depths and ground coverages were obtained from a vegetation characteristic data set. At each 0.5°×0.5° grid cell where vegetation is present, unit available water capacity (cm water per cm soil) was estimated from the sand, clay, and organic content of each profile horizon, and integrated over horizon thickness. Summation of the integrated values over the lesser of profile depth and root depth produced an estimate of the plant-extractable water capacity of soil.The global average of the estimated plant-extractable water capacities of soil is 86cm (Greenland, Antarctica and bare soil areas excluded). Estimates are less than 5, 10 and 15 cm - over approximately 30, 60, and 89 per cent of the area, respectively. Estimates reflect the combined effects of soil texture, soil organic content, and plant root depth or profile depth. The most influential and uncertain parameter is the depth over which the plant- extractable water capacity of soil is computed, which is usually limited by root depth. Soil texture exerts a lesser, but still substantial, influence. Organic content, except where concentrations are very high, has relatively little effect.

  4. Impact of repeated chlorotoluron application on its degradation in soil

    NASA Astrophysics Data System (ADS)

    Kocarek, Martin; Kodesova, Radka; Drabek, Ondrej; Kozak, Josef

    2010-05-01

    The effect of repeated chlorotoluron application on its degradation was studied under the field condition in Haplic Chernozem. Chlorotoluron was applied repeatedly (dose of 0.025 mg.m-2) on the top of the soil profile in years 2006, 2008 and 2009. Climatic data as a daily minimal and maximal temperature and daily rainfall were collected during the experiment. Pressure heads at 4 depths (10, 25, 50, 80 cm) were measured using tensiometers. Soil-water contents and temperatures at 5 depths (5, 10, 25, 50, 80 cm) were monitored using the ECH20 EC-TE sensors. The suction cups were used to take soil-water samples at various depths (5, 10, 25, 50 cm) to indentify presence of the herbicide during 140 days period. In addition, soil samples were taken from layers 2 cm thick (to the depth of 50 cm) 35, 50 and 140 day after the herbicide application to measure a total content of the applied herbicide in each layer within the soil profile. Herbicide concentrations in soil extracts and soil water samples were analyzed using the HPLC technology. The total chlorotoluron content within the monitored soil profile was evaluated, and the herbicide field degradation rate and half-life were calculated. Chlorotoluron was not detected below the depth of 32 cm during the entire experimental periods. Chlorotoluron field half-lives estimated in this study were 28.4, 33.4 and 32.3 days in 2006, 2008 and 2009, respectively. The herbicide half-lives were also measured in the laboratory under the controlled soil-water content and temperature conditions: 20.6 days (28 C, 40% soil-water content per mass), 33.16 days (28 C, 20% soil-water content per mass); 27.76 days (20 C, 40% soil-water content per mass); 39.85 days (20 C, 20% soil-water content per mass); 32.27 days (10 C, 40% soil-water content per mass); 45.7 days (10 C, 20% soil-water content per mass). The field herbicide half-lives (obtained under the similar average temperature and soil-water content conditions) corresponded to half

  5. Effects of tree diversity and environmental factors on the soil microbial community in three soil depth in a Central European beech forest

    NASA Astrophysics Data System (ADS)

    Fornacon, C.; Jacob, M.; Guckland, A.; Meinen, C.; Gleixner, G.

    2009-04-01

    We investigated the link between aboveground and belowground diversity in forest ecosystems. Therefore, we determined the effect of tree composition on amount and composition of the soil microbial community using phospholipid fatty acid profiles in the Hainich National Park in Thuringia, a deciduous mixed forest on loess over limestone in Central Germany. On the one hand we investigated the composition of the microbial community in dependence of leave litter composition, hypothesizing that distinct leave litter compositions activated signature PLFA's. On the other hand we determined if environmental factor like clay content or nutrient status influence the microbial community in deeper soil horizons. Consequently soil was sampled from depth intervals of 0-5 cm, 5-10 cm and 10-20 cm. Plots with highest diversity of leave litter had highest total amounts of fatty acids in the upper 5 cm. Mainly PLFA 16:1?5 was activated in autumn, being a common marker for mycorrhizal fungi. In soil depth below 5 cm the environmental factors like clay and soil nutrients like phosphorus and carbon, explained most of the soil microbial variability. On pure beech sites the total phosphorus content of soil influenced soil microbial diversity, but on sites with higher tree diversity no single factor varying the microbial community could be identified. Tree diversity and environmental factors together effect soil microbial community and are closely related to the link between aboveground and belowground diversity.

  6. [A spatial heterogeneity of surface soil moisture content in dry season in Mulun National Natural Reserve in Karst area].

    PubMed

    Song, Tong-qing; Peng, Wan-xia; Zeng, Fu-ping; Ouyang, Zi-wen; Wu, Hai-yong

    2009-01-01

    By the methods of classical statistics and geostatistics, the spatial heterogeneity of surface soil (0-5 cm and 5-10 cm layers) moisture content in dry season in the typical sloping fields and depressions in Mulun National Natural Reserve in Karst area were studied. The results indicated that in study area, the surface soil moisture content in dry season was still higher, and showed a fine semivariogram structure as a whole. The spatial distribution of moisture content in 0-5 cm and 5-10 cm soil layers, both for sloping fields and for depressions, fitted exponential model well. Under the same stand conditions, the moisture content in the two soil layers had the similar spatial structure and distribution pattern; while under different stand conditions, there existed obvious difference in the same soil layer. The spatial pattern of surface soil moisture content in sloping fields was characterized by medium spatial autocorrelation, clear patches with well continuum, relatively slow variation of Moran's I index, while that in depressions was characterized by strong spatial autocorrelation, larger variation of Moran' s I index, and more fragmented patches. Therefore, topography, micro-physiognomy, precipitation, human disturbance, and especially vegetation were the most important factors affecting the spatial pattern of soil moisture content in the Mulun National Natural Reserve, and to preserve primary forest should have favorable effect on the regulation of the spatial heterogeneity of soil moisture content in the Reserve.

  7. Sensing and 3D Mapping of Soil Compaction

    PubMed Central

    Tekin, Yücel; Kul, Basri; Okursoy, Rasim

    2008-01-01

    Soil compaction is an important physical limiting factor for the root growth and plant emergence and is one of the major causes for reduced crop yield worldwide. The objective of this study was to generate 2D/3D soil compaction maps for different depth layers of the soil. To do so, a soil penetrometer was designed, which was mounted on the three-point hitch of an agricultural tractor, consisting of a mechanical system, data acquisition system (DAS), and 2D/3D imaging and analysis software. The system was successfully tested in field conditions, measuring soil penetration resistances as a function of depth from 0 to 40 cm at 1 cm intervals. The software allows user to either tabulate the measured quantities or generate maps as soon as data collection has been terminated. The system may also incorporate GPS data to create geo-referenced soil maps. The software enables the user to graph penetration resistances at a specified coordinate. Alternately, soil compaction maps could be generated using data collected from multiple coordinates. The data could be automatically stratified to determine soil compaction distribution at different layers of 5, 10,.…, 40 cm depths. It was concluded that the system tested in this study could be used to assess the soil compaction at topsoil and the randomly distributed hardpan formations just below the common tillage depths, enabling visualization of spatial variability through the imaging software.

  8. 43 CFR 5.10 - Can I appeal a decision not to issue a permit?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Can I appeal a decision not to issue a permit? 5.10 Section 5.10 Public Lands: Interior Office of the Secretary of the Interior COMMERCIAL FILMING AND SIMILAR PROJECTS AND STILL PHOTOGRAPHY ON CERTAIN AREAS UNDER DEPARTMENT JURISDICTION...

  9. 43 CFR 5.10 - Can I appeal a decision not to issue a permit?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Can I appeal a decision not to issue a permit? 5.10 Section 5.10 Public Lands: Interior Office of the Secretary of the Interior COMMERCIAL FILMING AND SIMILAR PROJECTS AND STILL PHOTOGRAPHY ON CERTAIN AREAS UNDER DEPARTMENT JURISDICTION...

  10. 41 CFR 102-5.10 - What does this part cover?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false What does this part cover? 102-5.10 Section 102-5.10 Public Contracts and Property Management Federal Property Management... transport employees between their homes and places of work....

  11. 17 CFR 5.10 - Risk assessment recordkeeping requirements for retail foreign exchange dealers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... requirements for retail foreign exchange dealers. 5.10 Section 5.10 Commodity and Securities Exchanges... recordkeeping requirements for retail foreign exchange dealers. (a) Requirement to maintain and preserve information. (1) Each retail foreign exchange dealer registered with the Commission pursuant to section...

  12. Dynamics of Soil Heat Flux in Lowland Area: Estimating the Soil Thermal Conductivy

    NASA Astrophysics Data System (ADS)

    Zimmer, T.; Silveira, M. V.; Roberti, D. R.

    2013-05-01

    In this work, it is shown soil thermal conductivity estimates in a flooded irrigated rice culture located at the Paraíso do Sul city for two distinct periods. The thermal conductivity is higher when the heat storage is higher and the soil surface temperature is lower. The soil thermal conductivity is also dependant on the soil texture, porosity and moisture. Therefore, it varies from soil to soil and in the same soil, depending on its soil moisture. For approximately 80% of its growing season, lowland flooded irrigated rice ecosystems stay under a 5 - 10 cm water layer. It affects the partitioning of the energy and water balance components. Furthermore this planting technique differs substantially from any other upland non-irrigated or irrigated crop ecosystems where the majority of observational studies have been conducted. In the present work, the dynamic of soil heat flux (G) is analyzed and the soil thermal conductivity (Ks) is estimated using experimental data form soil heat flux and soil temperature in a rice paddy farm in a subtropical location in Southern Brazil. In this region, rice grows once a year at river lowlands and wetlands while the ground is kept bare during the remaining of the year. The soil type is Planossolo Hidromórfico Distrófico, characterized as a mix between sandy and clay soil. The soil heat flux (G) was experimentally estimated with the sensor Hukseflux (HFP01SC-L) at 7 cm bellow the soil surface. The soil temperature at 5 cm and 10 cm was experimentally estimated using the sensor STP01. The experimental soil heat flux was compared with estimated soil heat flux by two forms: (1) using a know Ks from literature for this type of soil in saturated conditions (Ks=1.58); (2) using Ks estimated using the inversion of the equation Qg=-ks* ((T10-T5)/ (Z2-Z1)), where T10 and T5 are the temperature in 10 and 5 cm above the soil and Z2-Z1 is the difference between the positions in temperature measurement. The study period for estimating the Ks

  13. Total organic carbon in aggregates as a soil recovery indicator

    NASA Astrophysics Data System (ADS)

    Luciene Maltoni, Katia; Rodrigues Cassiolato, Ana Maria; Amorim Faria, Glaucia; Dubbin, William

    2015-04-01

    The soil aggregation promotes physical protection of organic matter, preservation of which is crucial to improve soil structure, fertility and ensure the agro-ecosystems sustainability. The no-tillage cultivation system has been considered as one of the strategies to increase total soil organic carbono (TOC) contents and soil aggregation, both are closely related and influenced by soil management systems. The aim of this study was to evaluate the distribution of soil aggregates and the total organic carbon inside aggregates, with regard to soil recovery, under 3 different soil management systems, i.e. 10 and 20 years of no-tillage cultivation as compared with soil under natural vegetation (Cerrado). Undisturbed soils (0-5; 5-10; and 10-20 cm depth) were collected from Brazil, Central Region. The soils, Oxisols from Cerrado, were collected from a field under Natural Vegetation-Cerrado (NV), and from fields that were under conventional tillage since 1970s, and 10 and 20 years ago were changed to no-tillage cultivation system (NT-10; NT-20 respectively). The undisturbed samples were sieved (4mm) and the aggregates retained were further fractionated by wet sieving through five sieves (2000, 1000, 500, 250, and 50 μm) with the aggregates distribution expressed as percentage retained by each sieve. The TOC was determined, for each aggregate size, by combustion (Thermo-Finnigan). A predominance of aggregates >2000 μm was observed under NV treatment (92, 91, 82 %), NT-10 (64, 73, 61 %), and NT-20 (71, 79, 63 %) for all three depths (0-5; 5-10; 10-20 cm). In addition greater quantities of aggregates in sizes 1000, 500, 250 and 50 μm under NT-10 and NT-20 treatments, explain the lower aggregate stability under these treatments compared to the soil under NV. The organic C concentration for NV in aggregates >2000 μm was 24,4; 14,2; 8,7 mg/g for each depth (0-5; 5-10; 10-20 cm, respectively), higher than in aggregates sized 250-50 μm (7,2; 5,5; 4,4 mg/g) for all depths

  14. Observed soil temperature trends associated with climate change in Canada

    NASA Astrophysics Data System (ADS)

    Qian, Budong; Gregorich, Edward G.; Gameda, Sam; Hopkins, David W.; Wang, Xiaolan L.

    2011-01-01

    Trends in soil temperature are important, but rarely reported, indicators of climate change. On the basis of the soil temperature data from 30 climate stations across Canada during 1958-2008, trends in soil temperatures at 5, 10, 20, 50, 100, and 150 cm depths were analyzed, together with atmospheric variables, such as air temperature, precipitation, and depth of snow on the ground, observed at the same locations. There was a significant positive trend with soil temperatures in spring and summer means, but not for the winter and annual means. A positive trend with time in soil temperature was detected at about two-thirds of the stations at all depths below 5 cm. A warming trend of 0.26-0.30°C/decade was consistently detected in spring (March-April-May) at all depths between 1958 and 2008. The warming trend in soil temperatures was associated with trends in air temperatures and snow cover depth over the same period. A significant decreasing trend in snow cover depth in winter and spring was associated with increasing air temperatures. The combined effects of the higher air temperature and reduced snow depth probably resulted in an enhanced increasing trend in spring soil temperatures, but no significant trends in winter soil temperatures. The thermal insulation by snow cover appeared to play an important role in the response of soil temperatures to climate change and must be accounted for in projecting future soil-related impacts of climate change.

  15. GNSSProbe, penetrating GNSS signals for measuring soil moisture

    NASA Astrophysics Data System (ADS)

    Martin, Francisco; Navarro, Victor; Reppucci, Antonio; Mollfulleda, Antonio; Balzter, Heiko; Nicolas-Perea, Virginia; Kissick, Lucy

    2016-04-01

    Soil moisture content (SMC) is an essential parameter from both a scientific and economical point of view. On one hand, it is key for the understanding of hydrological. Secondly, it is a most relevant parameter for agricultural activities and water management. Wide research has been done in this field using different sensors, spanning different parts of the measured electromagnetic spectrum, leading thus several methodologies to estimate soil moisture content. However complying with requirements in terms of accuracy and spatial resolution is still a major challenge. A novel approach based on the measurement of GNSS signals penetrating a soil volume is proposed here. This model relates soil moisture content to the measured soil transmissivity, and attenuation coefficient, which are a function of the soil characteristics (i.e soil moisture content, soit type, soil temperature, etc). A preliminary experiment has been performed to demonstrate the validity of this technique, where the signal received by a GNSS-R L1/E1 RHCP antenna buried at 5, 10, and 15 cm below the surface, was compared to the one received by a GNSS-R L1/E1 RHCP antenna with clear sky visibility. Preliminary results show agreement with theoretical results based on transmissivity and with previous campaigns performed where the soil moisture were collected at two different depths (5 and 15 cm). Details related to the GNSS soil moisture modeling, instrument preparation, measurement campaign, data processing and main results will be presented at the conference.

  16. The influence of different soil management practices on auxin herbicide interactions with organic carbon in soil aggregate fractions

    NASA Astrophysics Data System (ADS)

    Schnitzler, Frauke; Haupt, Nadine; Burauel, Peter; Berns, Anne E.

    2010-05-01

    The influence of changing organic carbon contents in soils on the sorption and/or sequestration mechanisms of xenobiotics and their bioavailability are still not understood precisely. The present work discusses the turnover of a crop residue interacting with processes like mobilisation, binding and metabolism of an auxin herbicide in soil. The soil type was a haplic chernozem, available in three crop production regimes (low, normal and high) due to three types of fertilisation (none, mineral and mineral & organic) [1]. Two sets of experiments were conducted with undisturbed soil columns under field-like conditions. In the first set 14C-labelled maize straw was incorporated into the top soil and after three months incubation the herbicide benazolin was applied. In the second set the unlabelled maize straw was incorporated first, then 14C-labelled benazolin was added. Soil layers of 0-5 cm and 5-10 cm were fractionated in according to a soil aggregate fractionation procedure [2]. The content of organic carbon and the distribution of benazolin and its metabolites were detected in the gained soil fractions. In general, the specific organic carbon content and the specific 14C-activity of benazolin and its metabolites increased in the order from sand-sized though silt-sized to clay fraction due to increasing specific surface areas and sorption sites of the mineral particles. The highest sorption capacity of benazolin and its metabolites was detected in the soil layers of 0-5 cm with mineral fertilisation. In the 5-10 cm soil layers the binding capacity increased with increasing crop production. It was shown that more than half of the residual 14C-activity was not extractable. LC-MS/MS analysis of the extracts showed that the major components were benazolin and the relatively non-mobile thiazolin. The amount of benazolin in the extracts increased with increasing crop production, but decreased with increasing soil depth. These results indicate that maize straw amendment

  17. Influence of depth and sampling time on bacterial community structure in an upland grassland soil.

    PubMed

    Griffiths, Robert I; Whiteley, Andrew S; O'Donnell, Anthony G; Bailey, Mark J

    2003-02-01

    Abstract Temporal and spatial variation of soil bacterial communities was evaluated with both molecular and metabolic profiling techniques. Soil cores (20 cm deep) were taken from an upland grassland in the Scottish Borders (UK) over 3 days in July 1999, and on single days in October 1999, April 2000, and August 2000. Cores were separated into four 5-cm depths to examine vertical spatial distribution. The 0-5-, 5-10- and 10-15-cm samples represented organic horizons whilst the 15-20-cm depths were from a mineral horizon. The potential metabolic activities were analysed using BIOLOG-GN plates, whereas genotypic diversity was evaluated using molecular profiling of amplified 16S rRNA and 16S rDNA gene fragments (denaturing gradient gel electrophoresis (DGGE)). BIOLOG-GN analysis revealed decreased substrate utilisation in the lowest depths, which was coupled with changes in the DNA and RNA DGGE profiles. Seasonal variation was pronounced in the 5-10-cm and 10-15-cm organic horizons for the July samplings whilst the 15-20-cm depths appeared more stable. Potential factors influencing the observed changes in bacterial communities resulting from soil depth and sampling time are discussed.

  18. Carbon Dynamics of Surface Soil after Land Use Change in a Seasonal Tropical Forest in North-eastern Thailand: Application of a Stable Carbon Isotope Mixing Model

    NASA Astrophysics Data System (ADS)

    Sakai, M.; Visaratana, T.; Sukchan, S.; Thaingam, R.; Okada, N.

    2015-12-01

    Globally, soil is vital to the mitigation of climate change. In tropical forests, the soil contains an estimated 216 Gt of carbon, equivalent to half of the total carbon in the tropical forest ecosystem. Little is known regarding changes in soil carbon following land use changes in tropical regions. We examined the differences in carbon dynamics in a chronosequence of Acacia mangium plantations established on grasslands following the deforestation of natural forest in north-eastern Thailand. The study site was located at the Sakaerat Silvicultural Research Station (14º28'06.1″N, 101º54'15.0″E; altitude 420 m asl), Nakhon Rachasima Province, north-eastern Thailand. Mean annual air temperature was 26ºC, and annual precipitation was 1,100 mm, with a dry (November-April) and wet (May-October) season. Soil carbon and the stable carbon isotope ratio (d13C) in the surface soil (0-5 and 5-10 cm deep) were determined at 12 and 24 years following establishment of A. mangium plantations, as well as for secondary forest and grassland. Using the stable carbon isotope mixing model based on differences in the natural abundance of d13C in plants with C3 (i.e., trees) and C4 (i.e., grasses) pathways for CO2 fixation, the amount of soil carbon derived from the plantations, forest, and grassland was calculated. Soil carbon at a depth of 10 cm was higher in the secondary forest (1,929 gCm-2) and grassland (2,508 gCm-2) than in the plantations (1,703 gCm-2 at 12 years, 1,673gCm-2 at 24 years). Soil carbon derived from A. mangium was 67% (0-5 cm deep) and 62% (5-10 cm deep) of total soil carbon at 12 years, and was 100% (0-5 cm deep) and 90% (5-10 cm deep) at 24 years in the plantations. We found that most of the soil carbon at a depth of 0-5 cm in the young plantation changed from grass-derived to tree-derived carbon within a relatively short period of 24 years. Because of changes in soil carbon, exotic, fast growing plantations like those of A. mangium are needed to quickly

  19. Soil microbial properties under different vegetation types on Mountain Han.

    PubMed

    Wang, Miao; Qu, Laiye; Ma, Keming; Yuan, Xiu

    2013-06-01

    This study investigated the influence of broadleaf and conifer vegetation on soil microbial communities in a distinct vertical distribution belt in Northeast China. Soil samples were taken at 0-5, 5-10 and 10-20 cm depths from four vegetation types at different altitudes, which were characterized by poplar (Populus davidiana) (1250-1300 m), poplar (P. davidiana) mixed with birch (Betula platyphylla) (1370-1550 m), birch (B. platyphylla) (1550-1720 m), and larch (Larix principis-rupprechtii) (1840-1890 m). Microbial biomass and community structure were determined using the fumigation-extraction method and phospholipid fatty acid (PLFA) analysis, and soil fungal community level physiological profiles (CLPP) were characterized using Biolog FF Microplates. It was found that soil properties, especially soil organic carbon and water content, contributed significantly to the variations in soil microbes. With increasing soil depth, the soil microbial biomass, fungal biomass, and fungal catabolic ability diminished; however, the ratio of fungi to bacteria increased. The fungal ratio was higher under larch forests compared to that under poplar, birch, and their mixed forests, although the soil microbial biomass was lower. The direct contribution of vegetation types to the soil microbial community variation was 12%. If the indirect contribution through soil organic carbon was included, variations in the vegetation type had substantial influences on soil microbial composition and diversity.

  20. Bacterial Community Structure after a 17-year Reciprocal Soil Transplant Simulating Climate Change with Elevation

    NASA Astrophysics Data System (ADS)

    Bailey, V. L.; McCue, L.; Fansler, S.; Bond-Lamberty, B. P.; Hess, N. J.; Smith, J. L.

    2013-12-01

    In 1994, a reciprocal soil transplant experiment was initiated between two elevations (310 m, warmer and drier, and 844 m, cooler and wetter) on Rattlesnake Mountain in southeastern Washington, USA. In March 2012 we resampled the original transplanted soils, control cores transplanted in situ, and native soils from each elevation, to study longer-term changes in microbial community composition, soil C and N dynamics, and soil physical structure. Our studies of these soils suggested that climate change has significantly altered the C dynamics in these soils, and that even after 17 years of adaptation, the soil microbial communities have not recovered to a condition similar to their new environment. To more thoroughly define the response of the native bacterial communities to this long-term transplant, we sequenced the V4 region of the 16S genes for all the treatments in this study, broken into 0-5, 5-10, and 10-15-cm depth intervals. Non-metric multidimensional scaling analyses of the sequence data reveal a strong surface influence, with some separation of the 5-10 and 10-15-cm depths. We are investigating these data, and companion metagenomic data, for signatures of the bacterial community's response to simulated climate change.

  1. Effects of stubble and mulching on soil erosion by wind in semi-arid China.

    PubMed

    Cong, Peifei; Yin, Guanghua; Gu, Jian

    2016-01-01

    Soil erosion is a growing challenge for agricultural production in Northern China. To explore the effect of variation in stubble height and mulching biomass on soil erosion caused by wind, we conducted a field experiment using a quadratic rotation combination design. Results showed that the quantity of straw mulch was the dominant factor affecting soil erosion, and stubble height was of secondary importance. The soil water content in stubble and straw mulching treatments was higher than in a control treatment at 0-20 cm soil, and the tendency in the amount of soil water content was opposite to the amount of wind erosion (r = -0.882, n = 10, p < 0.01). The change in soil water content observed in the stubble and mulch treatments at the 15-20 cm depth was higher than the change from 0-5 cm to 5-10cm. Combined, the influence of a stubble height of 34 cm and mulch quantity of 4260 kg·ha(-1) lowered the amount of erosion to 0.42 t·ha(-1), and increased the corn yield to 11900 kg·ha(-1). We determined that those were the most appropriate levels of stubble height and straw mulch for crop fields in the semi-arid regions of Northern China. PMID:27426048

  2. Effects of stubble and mulching on soil erosion by wind in semi-arid China.

    PubMed

    Cong, Peifei; Yin, Guanghua; Gu, Jian

    2016-07-18

    Soil erosion is a growing challenge for agricultural production in Northern China. To explore the effect of variation in stubble height and mulching biomass on soil erosion caused by wind, we conducted a field experiment using a quadratic rotation combination design. Results showed that the quantity of straw mulch was the dominant factor affecting soil erosion, and stubble height was of secondary importance. The soil water content in stubble and straw mulching treatments was higher than in a control treatment at 0-20 cm soil, and the tendency in the amount of soil water content was opposite to the amount of wind erosion (r = -0.882, n = 10, p < 0.01). The change in soil water content observed in the stubble and mulch treatments at the 15-20 cm depth was higher than the change from 0-5 cm to 5-10cm. Combined, the influence of a stubble height of 34 cm and mulch quantity of 4260 kg·ha(-1) lowered the amount of erosion to 0.42 t·ha(-1), and increased the corn yield to 11900 kg·ha(-1). We determined that those were the most appropriate levels of stubble height and straw mulch for crop fields in the semi-arid regions of Northern China.

  3. Effects of long-term use of different farming systems on some physical, chemical and microbiological parameters of soil quality

    NASA Astrophysics Data System (ADS)

    Gajda, Anna M.; Czyż, Ewa A.; Dexter, Anthony R.

    2016-04-01

    The aim of this study was to compare the effects of different farming systems (organic, integrated, conventional and monoculture) on some soil properties as: bulk density, contents of readily-dispersible clay, organic matter and particulate organic matter, and enzymatic activity measured in terms of the intensity of fluorescein diacetate hydrolysis. Soil under permanent grass was used as a control. The study was conducted on the 20 years lasting field experiment. Samples of Haplic Luvisol soil were collected twice a year on fields under winter wheat from the layers of 0-5, 5-10, 15-20, and 30-35 cm. Within arable soils the soil under organic farming contained the greatest amount of organic matter, which influenced strongly the readily-dispersible clay content, especially in the layer of 5-20 cm. The readily-dispersible clay content in soil under organic farming was 3 times lower, as compared to the conventional and monoculture farming. The highest contents of particulate organic matter 6.2 and 3.5 mg g-1 air dry soil, on average were measured in the 0-5 cm layer of control soil and soil under organic farming, respectively. Also, soil under organic farming and control soil from the depth of 0-5 cm showed 2-2.5 times greater activity of microorganisms in fluorescein diacetate hydrolysis than soil under conventional and monoculture farming. Increase of concentration of organic matter in soil under organic farming decreased soil bulk density. Statistical analysis showed significant correlations between studied parameters of soil quality and confirmed their effectiveness as indicators of disturbances in soil environment.

  4. 77 FR 8877 - ICD-9-CM Coordination and Maintenance (C&M) Committee Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-15

    ... HUMAN SERVICES Centers for Disease Control and Prevention ICD-9-CM Coordination and Maintenance (C&M... Standards Staff, announces the following meeting. Name: ICD-9-CM Coordination and Maintenance (C&M... attend the ICD- 9-CM C&M meeting on March 5, 2012, must submit their name and organization by February...

  5. Changes in soil carbon, nitrogen, and phosphorus due to land-use changes in Brazil

    NASA Astrophysics Data System (ADS)

    Groppo, J. D.; Lins, S. R. M.; Camargo, P. B.; Assad, E. D.; Pinto, H. S.; Martins, S. C.; Salgado, P. R.; Evangelista, B.; Vasconcellos, E.; Sano, E. E.; Pavão, E.; Luna, R.; Martinelli, L. A.

    2015-08-01

    In this paper, soil carbon, nitrogen and phosphorus concentrations and stocks were investigated in agricultural and natural areas in 17 plot-level paired sites and in a regional survey encompassing more than 100 pasture soils In the paired sites, elemental soil concentrations and stocks were determined in native vegetation (forests and savannas), pastures and crop-livestock systems (CPSs). Nutrient stocks were calculated for the soil depth intervals 0-10, 0-30, and 0-60 cm for the paired sites and 0-10, and 0-30 cm for the pasture regional survey by sum stocks obtained in each sampling intervals (0-5, 5-10, 10-20, 20-30, 30-40, 40-60 cm). Overall, there were significant differences in soil element concentrations and ratios between different land uses, especially in the surface soil layers. Carbon and nitrogen contents were lower, while phosphorus contents were higher in the pasture and CPS soils than in native vegetation soils. Additionally, soil stoichiometry has changed with changes in land use. The soil C : N ratio was lower in the native vegetation than in the pasture and CPS soils, and the carbon and nitrogen to available phosphorus ratio (PME) decreased from the native vegetation to the pasture to the CPS soils. In the plot-level paired sites, the soil nitrogen stocks were lower in all depth intervals in pasture and in the CPS soils when compared with the native vegetation soils. On the other hand, the soil phosphorus stocks were higher in all depth intervals in agricultural soils when compared with the native vegetation soils. For the regional pasture survey, soil nitrogen and phosphorus stocks were lower in all soil intervals in pasture soils than in native vegetation soils. The nitrogen loss with cultivation observed here is in line with other studies and it seems to be a combination of decreasing organic matter inputs, in cases where crops replaced native forests, with an increase in soil organic matter decomposition that leads to a decrease in the long

  6. Teaching for Creativity by Science Teachers in Grades 5-10

    ERIC Educational Resources Information Center

    Al-Abdali, Nasser S.; Al-Balushi, Sulaiman M.

    2016-01-01

    This classroom observation study explored how science teachers (N = 22) teach for creativity in grades 5-10 in Oman. We designed an observation form with 4 main categories that targeted the instructional practices related to teaching for creativity: questioning strategy, teacher's responses to students' ideas, classroom activities to support…

  7. The corrole and ferrocene marriage: 5,10,15-triferrocenylcorrolato Cu.

    PubMed

    Pomarico, Giuseppe; Vecchi, Andrea; Mandoj, Federica; Bortolini, Olga; Cicero, Daniel O; Galloni, Pierluca; Paolesse, Roberto

    2014-04-21

    Two synthetic routes have been defined for the preparation of a 5,10,15-triferrocenylcorrole Cu derivative. This complex has been characterized and the preliminary electrochemical investigation shows a strong interaction among the corrole and meso ferrocenyl substituents. The results obtained suggest that peculiar properties are gained by combining the eccentric characteristics of ferrocenyl substitution with the corrole macrocycle. PMID:24616907

  8. Compositional Homogeneity of CM Parent Bodies

    NASA Astrophysics Data System (ADS)

    Vernazza, P.; Marsset, M.; Beck, P.; Binzel, R. P.; Birlan, M.; Cloutis, E. A.; DeMeo, F. E.; Dumas, C.; Hiroi, T.

    2016-09-01

    CM chondrites are the most common type of hydrated meteorites, making up ˜1.5% of all falls. Whereas most CM chondrites experienced only low-temperature (˜0°C–120°C) aqueous alteration, the existence of a small fraction of CM chondrites that suffered both hydration and heating complicates our understanding of the early thermal evolution of the CM parent body(ies). Here, we provide new constraints on the collisional and thermal history of CM-like bodies from a comparison between newly acquired spectral measurements of main-belt Ch/Cgh-type asteroids (70 objects) and existing laboratory spectral measurements of CM chondrites. It first appears that the spectral variation observed among CM-like bodies is essentially due to variations in the average regolith grain size. Second, the spectral properties of the vast majority (unheated) of CM chondrites resemble both the surfaces and the interiors of CM-like bodies, implying a “low” temperature (<300°C) thermal evolution of the CM parent body(ies). It follows that an impact origin is the likely explanation for the existence of heated CM chondrites. Finally, similarly to S-type asteroids and (2) Pallas, the surfaces of large (D > 100 km)—supposedly primordial—Ch/Cgh-type main-belt asteroids likely expose the interiors of the primordial CM parent bodies, a possible consequence of impacts by small asteroids (D < 10 km) in the early solar system.

  9. Compositional Homogeneity of CM Parent Bodies

    NASA Astrophysics Data System (ADS)

    Vernazza, P.; Marsset, M.; Beck, P.; Binzel, R. P.; Birlan, M.; Cloutis, E. A.; DeMeo, F. E.; Dumas, C.; Hiroi, T.

    2016-09-01

    CM chondrites are the most common type of hydrated meteorites, making up ˜1.5% of all falls. Whereas most CM chondrites experienced only low-temperature (˜0°C-120°C) aqueous alteration, the existence of a small fraction of CM chondrites that suffered both hydration and heating complicates our understanding of the early thermal evolution of the CM parent body(ies). Here, we provide new constraints on the collisional and thermal history of CM-like bodies from a comparison between newly acquired spectral measurements of main-belt Ch/Cgh-type asteroids (70 objects) and existing laboratory spectral measurements of CM chondrites. It first appears that the spectral variation observed among CM-like bodies is essentially due to variations in the average regolith grain size. Second, the spectral properties of the vast majority (unheated) of CM chondrites resemble both the surfaces and the interiors of CM-like bodies, implying a “low” temperature (<300°C) thermal evolution of the CM parent body(ies). It follows that an impact origin is the likely explanation for the existence of heated CM chondrites. Finally, similarly to S-type asteroids and (2) Pallas, the surfaces of large (D > 100 km)—supposedly primordial—Ch/Cgh-type main-belt asteroids likely expose the interiors of the primordial CM parent bodies, a possible consequence of impacts by small asteroids (D < 10 km) in the early solar system.

  10. [Impact of tillage practices on microbial biomass carbon in top layer of black soils].

    PubMed

    Sun, Bing-jie; Jia, Shu-xia; Zhang, Xiao-ping; Liang, Ai-zhen; Chen, Xue-wen; Zhang, Shi-xiu; Liu, Si-yi; Chen, Sheng-long

    2015-01-01

    A study was conducted on a long-term (13 years) tillage and rotation experiment on black soil in northeast China to determine the effects of tillage, time and soil depth on soil microbial biomass carbon (MBC). Tillage systems included no tillage (NT), ridge tillage (RT) and mould-board plough (MP). Soil sampling was done at 0-5, 5-10 and 10-20 cm depths in June, August and September, 2013, and April, 2014 in the corn phase of corn-soybean rotation plots. MBC content was measured by the chloroform fumigation extraction (CFE) method. The results showed that the MBC content varied with sampling time and soil depth. Soil MBC content was the lowest in April for all three tillage systems, and was highest in June for MP, and highest in August for NT and RT. At each sampling time, tillage system had a significant effect on soil MBC content only in the top 0-5 cm layer. The MBC content showed obvious stratification under NT and RT with a higher MBC content in the top 0-5 cm layer than under MP. The stratification ratios under NT and RT were greatest in September when they were respectively 67.8% and 95.5% greater than under MP. Our results showed that soil MBC contents were greatly affected by the time and soil depth, and were more apparently accumulated in the top layer under NT and RT.

  11. Mobility of spiromesifen in packed soil columns under laboratory conditions.

    PubMed

    Mate, Ch Jamkhokai; Mukherjee, Irani; Das, Shaon Kumar

    2014-11-01

    On percolating water equivalent to 1,156 mm of rainfall, spiromesifen formulation did not leach out of 25-cm long columns, and 62.7 % of this was recovered in 5-10-cm soil depth. In columns treated with the analytical grade, 52.40 % of the recovered spiromesifen was confined to 0-5-cm soil depth, with 0.04 % in leachate fraction, suggesting high adsorption in soil. Results revealed that percolating 400 mL of water, residues of enol metabolite of spiromesifen was detected up to 20-25-cm soil layer, with 23.50 % residues of spiromesifen in this layer and 1.73 % in the leachate fraction indicating that metabolite is more mobile as compared to the parent compound. Results suggested a significant reduction in leaching losses of enol metabolite in amended soil columns with 5 % nano clay, farmyard manure (FYM), and vermicompost. No enol spiromesifen was recovered in the leachate in columns amended with nano clay, vermicompost, and FYM; however, 85.30, 70.5, and 65.40 %, respectively, was recovered from 0-5 cm-soil depth of column after percolating water equivalent to 1,156 mm of rainfall. Spiromesifen formulation is less mobile in sandy loam soil than analytical grade spiromesifen. The metabolite, enol spiromesifen, is relatively more mobile than the parent compound and may leach into groundwater. The study suggested that amendments were very effective in reducing the downward mobility of enol metabolite in soil column. Further, it resulted in greater retention of enol metabolite in the amendment application zone. PMID:25060860

  12. Gas-Phase Oxidation of Cm+ and Cm2+ -- Thermodynamics of neutral and ionized CmO

    SciTech Connect

    Gibson, John K; Haire, Richard G.; Santos, Marta; Pires de Matos, Antonio; Marcalo, Joaquim

    2008-12-08

    Fourier transform ion cyclotron resonance mass spectrometry was employed to study the products and kinetics of gas-phase reactions of Cm+ and Cm2+; parallel studies were carried out with La+/2+, Gd+/2+ and Lu+/2+. Reactions with oxygen-donor molecules provided estimates for the bond dissociation energies, D[M+-O](M = Cm, Gd, Lu). The first ionization energy, IE[CmO], was obtained from the reactivity of CmO+ with dienes, and the second ionization energies, IE[MO+](M = Cm, La, Gd, Lu), from the rates of electron-transfer reactions from neutrals to the MO2+ ions. The following thermodynamic quantities for curium oxide molecules were obtained: IE[CmO]= 6.4+-0.2 eV; IE[CmO+]= 15.8+-0.4 eV; D[Cm-O]= 710+-45 kJ mol-1; D[Cm+-O]= 670+-40 kJ mol-1; and D[Cm2+-O]= 342+-55 kJ mol-1. Estimates for the M2+-O bond energies for M = Cm, La, Gd and Lu are all intermediate between D[N2-O]and D[OC-O]--i.e., 167 kJ mol-1< D[M2+-O]< 532 kJ mol-1 -- such that the four MO2+ ions fulfill the thermodynamic requirement for catalytic O-atom transport from N2O to CO. It was demonstrated that the kinetics are also favorable and that the CmO2+, LaO2+, GdO2+ and LuO2+ dipositive ions each catalyze the gas-phase oxidation of CO to CO2 by N2O. The CmO2+ ion appeared during the reaction of Cm+ with O2 when the intermediate, CmO+, was not collisionally cooled -- although its formation is kinetically and/or thermodynamically unfavorable, CmO2+ is a stable species.

  13. The mobility of thiobencarb and fipronil in two flooded rice-growing soils.

    PubMed

    Doran, Gregory; Eberbach, Philip; Helliwell, Stuart

    2008-08-01

    The mobility of the rice pesticides thiobencarb (S-[(4-chlorophenyl) methyl] diethylcarbamothioate) and fipronil ([5-amino-3-cyano-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethyl)sulfinyl]pyrazole) were investigated in the glasshouse under flooded conditions using two Australian rice-growing soils. When using leakage rates of 10 mm day(-1), less than 20% of applied thiobencarb and fipronil remained in the water column after 10 days due to rapid transfer to the soil phase. Up to 70% and 65% of the applied thiobencarb and fipronil, respectively, were recovered from the 0-1 cm layer of soils. Only 5-7% of each pesticide was recovered from the 1-2 cm layer, and less than 2% was recovered from each 1 cm layer in the 2-10 cm region of the soils. Analysis of the water leaking from the base of the soil cores showed between 5-10% of the applied thiobencarb and between 10-20% of the applied fipronil leaching from the soil cores. The high levels of pesticide in the effluent was attributed to preferential flow of pesticide-laden water via soil macropores resulting from the wetting and drying process, worm holes and root channels. PMID:18665985

  14. [Effects of precipitation variation on growing seasonal dynamics of soil microbial biomass in broadleaved Korean pine mixed forest].

    PubMed

    Wang, Ning; Wang, Mei-ju; Li, Shi-lan; Wang, Nan-nan; Feng, Fu-juan; Han, Shi-jie

    2015-05-01

    Broadleaved Korean pine mixed forest is the zonal climax vegetation in Northeast China and it plays a significant role in maintaining the ecological security. Changbai Mountains is a suitable region to study the positive and negative feedback mechanisms of temperate forest for precipitation variation. This study analyzed responses of soil microbial biomass carbon (SMBC) and microbial biomass nitrogen (SMBN) to precipitation variation (± 30%) in original broadleaved Korean pine mixed forest of Changbai Mountains. The results showed that, during the growing seasons (from May to September), the averages of SMBC and SMBN were 879.09 and 100.03 mg · kg(-1), respectively. Moreover, both of these two parameters gradually decreased with the soil depth. The contents of SMBC and SMBN all increased with the increasing precipitation, and the changes of SMBC and SMBN in the 0-5 cm soil layer were stronger than in the 5-10 cm soil layer. The value of SMBC/SMBN declined with the increase of precipitation. The precipitation variation significantly influenced the means of SMBC and SMBN. Compared with precipitation reduction, precipitation enhancement affected the indices much significantly. Both SMBC and SMBN showed similar seasonal patterns, which were the lowest in May, and after that, they increased and then decreased and increased again, showing 1-2 peaks in the growing season. However, the value and occurring time of the peaks varied with the precipitation and soil layer, and the seasonal variations of SMBC and SMBN in the 0-5 cm soil layer were higher than in the 5-10 cm soil layer. SMBC and SMBN had significant positive correlation with organic matter and total nitrogen content. The variances of soil physical and chemical properties caused by precipitation variation were closely related with the difference in spatial-temporal patterns of the soil microbial biomass in the forest. In conclusion, the precipitation variations could cause the change of the soil microbial

  15. [Effects of precipitation variation on growing seasonal dynamics of soil microbial biomass in broadleaved Korean pine mixed forest].

    PubMed

    Wang, Ning; Wang, Mei-ju; Li, Shi-lan; Wang, Nan-nan; Feng, Fu-juan; Han, Shi-jie

    2015-05-01

    Broadleaved Korean pine mixed forest is the zonal climax vegetation in Northeast China and it plays a significant role in maintaining the ecological security. Changbai Mountains is a suitable region to study the positive and negative feedback mechanisms of temperate forest for precipitation variation. This study analyzed responses of soil microbial biomass carbon (SMBC) and microbial biomass nitrogen (SMBN) to precipitation variation (± 30%) in original broadleaved Korean pine mixed forest of Changbai Mountains. The results showed that, during the growing seasons (from May to September), the averages of SMBC and SMBN were 879.09 and 100.03 mg · kg(-1), respectively. Moreover, both of these two parameters gradually decreased with the soil depth. The contents of SMBC and SMBN all increased with the increasing precipitation, and the changes of SMBC and SMBN in the 0-5 cm soil layer were stronger than in the 5-10 cm soil layer. The value of SMBC/SMBN declined with the increase of precipitation. The precipitation variation significantly influenced the means of SMBC and SMBN. Compared with precipitation reduction, precipitation enhancement affected the indices much significantly. Both SMBC and SMBN showed similar seasonal patterns, which were the lowest in May, and after that, they increased and then decreased and increased again, showing 1-2 peaks in the growing season. However, the value and occurring time of the peaks varied with the precipitation and soil layer, and the seasonal variations of SMBC and SMBN in the 0-5 cm soil layer were higher than in the 5-10 cm soil layer. SMBC and SMBN had significant positive correlation with organic matter and total nitrogen content. The variances of soil physical and chemical properties caused by precipitation variation were closely related with the difference in spatial-temporal patterns of the soil microbial biomass in the forest. In conclusion, the precipitation variations could cause the change of the soil microbial

  16. Effects on cardiovascular risk factors of weight losses limited to 5-10.

    PubMed

    Brown, Joshua D; Buscemi, Joanna; Milsom, Vanessa; Malcolm, Robert; O'Neil, Patrick M

    2016-09-01

    Little is known about the cardiovascular effects of modest weight loss. To determine whether weight losses limited to 5-10 % are sufficient to produce cardiovascular health benefits, data from 401 overweight and obese adults who enrolled in a behavioral weight loss program from 2003 to 2011 were analyzed. Primary outcomes were changes in fasting glucose, triglycerides, and cholesterol. Patients who lost 5-10 % showed significant reductions in triglycerides, total cholesterol, and low-density lipoprotein (LDL) cholesterol. Patients who lost >10 % experienced significantly greater improvements in triglycerides, total cholesterol, and LDL cholesterol than patients losing less. For higher-risk patients, those who lost 5-10 % significantly reduced fasting glucose, triglycerides, and total cholesterol; those who lost >10 % improved on all risk factors (except HDL cholesterol) and to a significantly greater degree than those losing less. Five to 10 % weight losses produced improvements in cardiovascular risk factors, but greater weight losses were associated with even greater improvement. PMID:27528523

  17. Soil water storage capacity under chronosequence of revegetation in Yanhe watershed on the Loess Plateau, China.

    PubMed

    Jiao, Feng; Wen, Zhong-Ming; An, Shao-Shan

    2013-01-01

    The relationship between vegetation and soil moisture deserves attention due to its scientific importance and practical applications. However, the effects of soil moisture on vegetation development and succession are poorly documented. Here we study soil water storage in Yanhe watershed at northern Shaanxi on five different land uses, namely shrubland, farmland, natural grassland, woodland, and artificial grassland, and in soil under restoration for 5, 10, 15, 20 and 25. The results show that (1) soil water in soil 0-60 cm below ground is the highest in farmland, and lower in shrubland, artificial grassland, natural grassland and woodland; (2) soil water in artificial grassland and woodland decreases rapidly as the soil depth increases; whereas soil water in farmland, natural grassland, shrubland and woodland decreases; (3) soil water storage of farmland is greater than that of shrubland, artificial grassland, natural grassland and woodland; and (4) the vegetation succession in soil undergo restoration for different years on eroded soil results in a decrease in soil water storage.

  18. In vitro cytotoxicity assessment of [5,10,15,20-tetra (4-sulfophenyl) porphyrin] on tumor and nontumor cell lines

    NASA Astrophysics Data System (ADS)

    Alexandrova, R.; Sabotinov, O.; Stoykova, Elena V.; Ion, Rodica-Mariana; Shurulinkov, Stanislav; Minchev, Georgi

    2004-06-01

    In this study we evaluate the cytotoxicity of 5,10,15,20- tetra (4-sulfophenyl) porphyrins on a tumor cell line LSCC-SF-Mc29, obtained from a transplantable chicken hepatoma induced by the myelocytomatosis virus Mc29, a timor line LSR-SF-SR, obtained from a transplantable sarcoma in rat induced by Rous sarcoma virus strain Schmidt-Ruppin and for normal mouse cell line (BALB/c-3T3-A31) and bovine kidney cell line (MDBK). The cells were exposed to irradiation from a pulsed CuBr vapor laser system at 510.6 nm and 578.2 nm at fluence rate 50 mW/cm2 and pulse frequency rate 20 kHz. The viability of cells was determined by the neutral red uptake cytotoxicity assay. The light dose-response curves and light exposures that ensure viability drop to 50 % were obtained for each cell line. The cytotoxic effect of TS4PP is most distinguished for LSCC-SF-Mc29. The bovine cell line is more vulnerable than the mouse line, especially at 510.6 nm. The 2-4 times higher viability of the normal cell lines in comparison with the tumor lines has been obtained.

  19. Depth distribution of glyphosate and AMPA under diferent tillage system and soils in long-term experiments

    NASA Astrophysics Data System (ADS)

    Aparicio, Virginia; Costa, Jose Luis; De Geronimo, Eduardo

    2016-04-01

    Glyphosate (N-(phosphonomethyl glycine) is a post-emergence, non-selective, foliar herbicide. Around 200 million liters of this herbicide are applied every year in Argentina, where the main agricultural practice is no-till (NT), accounting for 78 % of the cultivated land. In this work, we studied the depth distribution of glyphosate in long-term experiments (more than 15 years) at different locations under NT and conventional tillage (CT). Samples from 0-2, 2-5, 5-10, 10-15, and 15-20 cm depth with four replication and two treatments NT CT at three locations: Balcarce (BA) a loam soil, Bordenave (BO) a sandy loam soil y Marcos Juarez a silty loam soil (MJ). The glyphosate concentration in the first 2 cm of soil was, on the average, 70% greater than in the next 2-5 cm. The mass of glyphosate in CT was higher at 2 to 10 cm depth. The depth concentration of AMPA follows the same trend than glyphosate, although its average concentration at 0-2 cm depth is 28 times higher than the glyphosate concentration at 2-5 cm (glyphosate = 147 ppb and AMPA = 4100 ppb). Beside the AMPA concentration at 0-2 cm depth is greater in NT than in CT, the mass of AMPA is higher in CT only for the Balcarce location. To our knowledge, this study is the first dealing with the depth distribution of glyphosate concentration in soils under different soil managements. In the present study, it was demonstrated that glyphosate and AMPA are present in soils under agricultural activity with maximum concentration in the first two cm of soil and the AMPA concentration at this depth is greater in NT than in CT.

  20. Soil temperature regime and vulnerability due to extreme soil temperatures in Croatia

    NASA Astrophysics Data System (ADS)

    Sviličić, Petra; Vučetić, Višnja; Filić, Suzana; Smolić, Ante

    2016-10-01

    Soil temperature is an important factor within the climate system. Changes of trends in soil temperature and analysis of vulnerability due to heat stress can provide useful information on climate change. In this paper, the soil temperature regime was analyzed on seasonal and annual scales at depths of 2, 5, 10, 20, 30, and 50 cm at 26 sites in Croatia. Trends of maximal, mean, and minimal soil temperatures were analyzed in the periods 1961-2010 and 1981-2010. Duration of extreme soil temperatures and vulnerability due to high or low soil temperatures in the recent standard period 1981-2010 was compared with the reference climate period 1961-1990. The results show a general warming in all seasons and depths for maximal and mean temperatures in both observed periods, while only at some locations for minimal soil temperature. Warming is more pronounced in the eastern and coastal parts of Croatia in the surface layers, especially in the spring and summer season in the second period. Significant trends of maximal, minimal, and mean soil temperature in both observed periods range from 2.3 to 6.6 °C/decade, from -1.0 to 1.3 °C/decade, and from 0.1 to 2.5 °C/decade, respectively. The highest vulnerability due to heat stress at 35 °C is noted in the upper soil layers of the coastal area in both observed periods. The mountainous and northwestern parts of Croatia at surface soil layers are the most vulnerable due to low soil temperature below 0 °C. Vulnerability due to high or low soil temperature decreases with depth.

  1. Soil temperature regime and vulnerability due to extreme soil temperatures in Croatia

    NASA Astrophysics Data System (ADS)

    Sviličić, Petra; Vučetić, Višnja; Filić, Suzana; Smolić, Ante

    2015-08-01

    Soil temperature is an important factor within the climate system. Changes of trends in soil temperature and analysis of vulnerability due to heat stress can provide useful information on climate change. In this paper, the soil temperature regime was analyzed on seasonal and annual scales at depths of 2, 5, 10, 20, 30, and 50 cm at 26 sites in Croatia. Trends of maximal, mean, and minimal soil temperatures were analyzed in the periods 1961-2010 and 1981-2010. Duration of extreme soil temperatures and vulnerability due to high or low soil temperatures in the recent standard period 1981-2010 was compared with the reference climate period 1961-1990. The results show a general warming in all seasons and depths for maximal and mean temperatures in both observed periods, while only at some locations for minimal soil temperature. Warming is more pronounced in the eastern and coastal parts of Croatia in the surface layers, especially in the spring and summer season in the second period. Significant trends of maximal, minimal, and mean soil temperature in both observed periods range from 2.3 to 6.6 °C/decade, from -1.0 to 1.3 °C/decade, and from 0.1 to 2.5 °C/decade, respectively. The highest vulnerability due to heat stress at 35 °C is noted in the upper soil layers of the coastal area in both observed periods. The mountainous and northwestern parts of Croatia at surface soil layers are the most vulnerable due to low soil temperature below 0 °C. Vulnerability due to high or low soil temperature decreases with depth.

  2. Evaluation of soil moisture sensors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study evaluated the measurement accuracy and repeatability of the EC-5 and 5TM soil volumetric water content (SVWC) sensors, MPS-2 and 200SS soil water potential (SWP) sensors, and 200TS soil temperature sensor. Six 183cm x 183cm x 71cm wooden compartments were built inside a greenhouse, and e...

  3. Purification and characterization of NADP(+)-dependent 5,10-methylenetetrahydrofolate dehydrogenase from Peptostreptococcus productus marburg.

    PubMed Central

    Wohlfarth, G; Geerligs, G; Diekert, G

    1991-01-01

    The 5,10-methylenetetrahydrofolate dehydrogenase of heterotrophically grown Peptostreptococcus productus Marburg was purified to apparent homogeneity. The purified enzyme catalyzed the reversible oxidation of methylenetetrahydrofolate with NADP+ as the electron acceptor at a specific activity of 627 U/mg of protein. The Km values for methylenetetrahydrofolate and for NADP+ were 27 and 113 microM, respectively. The enzyme, which lacked 5,10-methenyltetrahydrofolate cyclohydrolase activity, was insensitive to oxygen and was thermolabile at temperatures above 40 degrees C. The apparent molecular mass of the enzyme was estimated by gel filtration to be 66 kDa. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed the presence of a single subunit of 34 kDa, accounting for a dimeric alpha 2 structure of the enzyme. Kinetic studies on the initial reaction velocities with different concentrations of both substrates in the absence and presence of NADPH as the reaction product were interpreted to indicate that the enzyme followed a sequential reaction mechanism. After gentle ultracentrifugation of crude extracts, the enzyme was recovered to greater than 95% in the soluble (supernatant) fraction. Sodium (10 microM to 10 mM) had no effect on enzymatic activity. The data were taken to indicate that the enzyme was similar to the methylenetetrahydrofolate dehydrogenases of other homoacetogenic bacteria and that the enzyme is not involved in energy conservation of P. productus. PMID:1899860

  4. [Influence of different types of surface on the diversity of soil fauna in Beijing Olympic Park].

    PubMed

    Song, Ying-shi; Li, Xiao-wen; Li, Feng; Li, Hai-mei

    2015-04-01

    Soil fauna are impacted by urbanization. In order to explore the stress of different surface covers on diversity and community structure of soil fauna, we conducted this experiment in Beijing Olympic Park. In autumn of 2013, we used Baermann and Tullgren methods to study the diversity of soil fauna in the depth of 0-5 cm, 5-10 cm, 10-15 cm under four different land covers i.e. bared field (BF), totally impervious surface (TIS), partly impervious surface (PIS) and grassland (GL). The results showed that the total number of soil fauna in 100 cm3 was in order of GL (210) > PIS (193) > TIS (183) > BF (90), and the number of nematodes accounted for 72.0%-92.8% of the total number. On the vertical level, except for the TIS, the other three types of surface soil fauna had the surface gathered phenomenon. The Shannon diversity index and the Pielou evenness index of BF were lower, but the Simpson dominance index was higher than in the other land covers. The Shannon index and Margalef richness indes of GL were higher than those of the other land covers. The Shannon indexes of TIS and PIS were between the BF and GL. Except for the TIS and GL, the similarity indexes were between 0.4-0.5, indicating moderate non-similar characteristics. The diversity of soil fauna was significantly correlated with temperature, pH and available potassium.

  5. Linking hydraulic properties of fire-affected soils to infiltration and water repellency

    USGS Publications Warehouse

    Moody, J.A.; Kinner, D.A.; Ubeda, X.

    2009-01-01

    Heat from wildfires can produce a two-layer system composed of extremely dry soil covered by a layer of ash, which when subjected to rainfall, may produce extreme floods. To understand the soil physics controlling runoff for these initial conditions, we used a small, portable disk infiltrometer to measure two hydraulic properties: (1) near-saturated hydraulic conductivity, Kf and (2) sorptivity, S(??i), as a function of initial soil moisture content, ??i, ranging from extremely dry conditions (??i < 0.02 cm3 cm-3) to near saturation. In the field and in the laboratory replicate measurements were made of ash, reference soils, soils unaffected by fire, and fire-affected soils. Each has a different degrees of water repellency that influences Kf and S(??i). Values of Kf ranged from 4.5 ?? 10-3 to 53 ?? 10-3 cm s-1 for ash; from 0.93 ?? 10-3 to 130 ?? 10-3 cm s-1 for reference soils; and from 0.86 ?? 10-3 to 3.0 ?? 10-3 cm s-1, for soil unaffected by fire, which had the lowest values of Kf. Measurements indicated that S(??i) could be represented by an empirical non-linear function of ??i with a sorptivity maximum of 0.18-0.20 cm s-0.5, between 0.03 and 0.08 cm3 cm-3. This functional form differs from the monotonically decreasing non-linear functions often used to represent S(??i) for rainfall-runoff modeling. The sorptivity maximum may represent the combined effects of gravity, capillarity, and adsorption in a transitional domain corresponding to extremely dry soil, and moreover, it may explain the observed non-linear behavior, and the critical soil-moisture threshold of water repellent soils. Laboratory measurements of Kf and S(??i) are the first for ash and fire-affected soil, but additional measurements are needed of these hydraulic properties for in situ fire-affected soils. They provide insight into water repellency behavior and infiltration under extremely dry conditions. Most importantly, they indicate how existing rainfall-runoff models can be modified to

  6. Soil organic carbon and nitrogen accumulation on coal mine spoils reclaimed with maritime pine (Pinus pinaster Aiton) in Agacli-Istanbul.

    PubMed

    Sever, Hakan; Makineci, Ender

    2009-08-01

    Mining operations on open coal mines in Agacli-Istanbul have resulted in the destruction of vast amounts of land. To rehabilitate these degraded lands, plantations on this area began in 1988. Twelve tree species were planted, however, the most planted tree species was maritime pine (Pinus pinaster Aiton). This study performed on 14 sample plots randomly selected in maritime pine plantations on coal mine soil/spoils in 2005. Soil samples were taken from eight different soil layers (0-1, 1-3, 3-5, 5-10, 10-20, 20-30, 30-40 and 40-50 cm) into the soil profile. On soil samples; fine soil fraction (<2 mm), soil acidity (pH), organic carbon (C(org)) and total nitrogen (N(t)) contents were investigated, and results were compared statistically among soil layers. As a result, 17 years after plantations, total forest floor accumulation determined as 17,973.20 kg ha(-1). Total nitrogen and organic matter amounts of forest floor were 113.90 and 14,640.92 kg ha(-1) respectively. Among soil layers, the highest levels of organic carbon (1.77%) and total nitrogen (0.096%) and the lowest pH value (pH 5.38) were found in 0-1 cm soil layer, and the variation differs significantly among soil layers. Both organic carbon and total nitrogen content decreased, pH values increased from 0-1 to 5-10 cm layer. In conclusion, according to results obtained maritime pine plantations on coal mine spoils; slow accumulation and decomposition of forest floor undergo simultaneously. Depending on these changes organic carbon and total nitrogen contents increased in upper layer of soil/spoil. PMID:18604588

  7. Soil organic carbon and nitrogen accumulation on coal mine spoils reclaimed with maritime pine (Pinus pinaster Aiton) in Agacli-Istanbul.

    PubMed

    Sever, Hakan; Makineci, Ender

    2009-08-01

    Mining operations on open coal mines in Agacli-Istanbul have resulted in the destruction of vast amounts of land. To rehabilitate these degraded lands, plantations on this area began in 1988. Twelve tree species were planted, however, the most planted tree species was maritime pine (Pinus pinaster Aiton). This study performed on 14 sample plots randomly selected in maritime pine plantations on coal mine soil/spoils in 2005. Soil samples were taken from eight different soil layers (0-1, 1-3, 3-5, 5-10, 10-20, 20-30, 30-40 and 40-50 cm) into the soil profile. On soil samples; fine soil fraction (<2 mm), soil acidity (pH), organic carbon (C(org)) and total nitrogen (N(t)) contents were investigated, and results were compared statistically among soil layers. As a result, 17 years after plantations, total forest floor accumulation determined as 17,973.20 kg ha(-1). Total nitrogen and organic matter amounts of forest floor were 113.90 and 14,640.92 kg ha(-1) respectively. Among soil layers, the highest levels of organic carbon (1.77%) and total nitrogen (0.096%) and the lowest pH value (pH 5.38) were found in 0-1 cm soil layer, and the variation differs significantly among soil layers. Both organic carbon and total nitrogen content decreased, pH values increased from 0-1 to 5-10 cm layer. In conclusion, according to results obtained maritime pine plantations on coal mine spoils; slow accumulation and decomposition of forest floor undergo simultaneously. Depending on these changes organic carbon and total nitrogen contents increased in upper layer of soil/spoil.

  8. Influence of soil moisture on soil respiration

    NASA Astrophysics Data System (ADS)

    Fer, Miroslav; Kodesova, Radka; Nikodem, Antonin; Klement, Ales; Jelenova, Klara

    2015-04-01

    The aim of this work was to describe an impact of soil moisture on soil respiration. Study was performed on soil samples from morphologically diverse study site in loess region of Southern Moravia, Czech Republic. The original soil type is Haplic Chernozem, which was due to erosion changed into Regosol (steep parts) and Colluvial soil (base slope and the tributary valley). Soil samples were collected from topsoils at 5 points of the selected elevation transect and also from the parent material (loess). Grab soil samples, undisturbed soil samples (small - 100 cm3, and large - 713 cm3) and undisturbed soil blocks were taken. Basic soil properties were determined on grab soil samples. Small undisturbed soil samples were used to determine the soil water retention curves and the hydraulic conductivity functions using the multiple outflow tests in Tempe cells and a numerical inversion with HYDRUS 1-D. During experiments performed in greenhouse dry large undisturbed soil samples were wetted from below using a kaolin tank and cumulative water inflow due to capillary rise was measured. Simultaneously net CO2 exchange rate and net H2O exchange rate were measured using LCi-SD portable photosynthesis system with Soil Respiration Chamber. Numerical inversion of the measured cumulative capillary rise data using the HYDRUS-1D program was applied to modify selected soil hydraulic parameters for particular conditions and to simulate actual soil water distribution within each soil column in selected times. Undisturbed soil blocks were used to prepare thin soil sections to study soil-pore structure. Results for all soil samples showed that at the beginning of soil samples wetting the CO2 emission increased because of improving condition for microbes' activity. The maximum values were reached for soil column average soil water content between 0.10 and 0.15 cm3/cm3. Next CO2 emission decreased since the pore system starts filling by water (i.e. aggravated conditions for microbes

  9. Stratification and Storage of Soil Organic Carbon and Nitrogen as Affected by Tillage Practices in the North China Plain.

    PubMed

    Zhao, Xin; Xue, Jian-Fu; Zhang, Xiang-Qian; Kong, Fan-Lei; Chen, Fu; Lal, Rattan; Zhang, Hai-Lin

    2015-01-01

    Tillage practices can redistribute the soil profiles, and thus affects soil organic carbon (SOC), and its storage. The stratification ratio (SR) can be an indicator of soil quality. This study was conducted to determine tillage effects on the profile distribution of certain soil properties in winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) systems in the North China Plain (NCP). Three tillage treatments, including no till (NT), rotary tillage (RT), and plow tillage (PT), were established in 2001 in Luancheng County, Hebei Province. The concentration, storage, and SR of SOC and soil total nitrogen (TN) were assessed in both the wheat and maize seasons. Compared with RT and PT, the mean SRs for all depth ratios of SOC under NT increased by 7.85% and 30.61% during the maize season, and by 14.67% and 30.91% during the wheat season, respectively. The SR of TN for 0-5:30-50 cm increased by 140%, 161%, and 161% in the maize season, and 266%, 154%, and 122% in the wheat season compared to the SR for 0-5:5-10 cm under NT, RT and PT, respectively. The data indicated that SOC and TN were both concentrated in the surface-soil layers (0-10 cm) under NT but were distributed relatively evenly through the soil profile under PT. Meanwhile, the storage of SOC and TN was higher under NT for the surface soil (0-10 cm) but was higher under PT for the deeper soil (30-50 cm). Furthermore, the storage of SOC and TN was significantly related to SR of SOC and TN along the whole soil profile (P<0.0001). Therefore, SR could be used to explain and indicate the changes in the storage of SOC and TN. Further, NT stratifies SOC and TN, enhances the topsoil SOC storage, and helps to improve SOC sequestration and soil quality.

  10. Chilled Mirror Dew Point Hygrometer (CM) Handbook

    SciTech Connect

    Ritsche, MT

    2005-01-01

    The CM systems have been developed for the ARM Program to act as a moisture standard traceable to National Institute of Standards and Technology (NIST). There are three CM systems that are each fully portable, self-contained, and require only 110 V AC power. The systems include a CM sensor, air sampling and filtration system, a secondary reference (Rotronic HP043 temperature and relative humidity sensor) to detect system malfunctions, a data acquisition system, and data storage for more than one month of 1-minute data. The CM sensor directly measures dew point temperature at 1 m, air temperature at 2 m, and relative humidity at 2 m. These measurements are intended to represent self-standing data streams that can be used independently or in combinations.

  11. Structural distortions in 5-10 nm silver nanoparticles under high pressure

    SciTech Connect

    Koski, Kristie J.; Kamp, Noelle M.; Kunz, Martin; Knight, Jason K.; Alivisatos, A.P.; Smith, R.K.

    2008-10-13

    We present experimental evidence that silver nanoparticles in the size range of 5-10 nm undergo a reversible structural transformation under hydrostatic pressures up to 10 GPa. We have used x-ray diffraction with a synchrotron light source to investigate pressure-dependent and size-dependent trends in the crystal structure of silver nanoparticles in a hydrostatic medium compressed in a diamond-anvil cell. Results suggest a reversible linear pressure-dependent rhombohedral distortion which has not been previously observed in bulk silver. We propose a mechanism for this transition that considers the bond-length distribution in idealized multiply twinned icosahedral particles. To further support this hypothesis, we also show that similar measurements of single-crystal platinum nanoparticles reveal no such distortions.

  12. Warm-hot baryons comprise 5-10 per cent of filaments in the cosmic web.

    PubMed

    Eckert, Dominique; Jauzac, Mathilde; Shan, HuanYuan; Kneib, Jean-Paul; Erben, Thomas; Israel, Holger; Jullo, Eric; Klein, Matthias; Massey, Richard; Richard, Johan; Tchernin, Céline

    2015-12-01

    Observations of the cosmic microwave background indicate that baryons account for 5 per cent of the Universe's total energy content. In the local Universe, the census of all observed baryons falls short of this estimate by a factor of two. Cosmological simulations indicate that the missing baryons have not condensed into virialized haloes, but reside throughout the filaments of the cosmic web (where matter density is larger than average) as a low-density plasma at temperatures of 10(5)-10(7) kelvin, known as the warm-hot intergalactic medium. There have been previous claims of the detection of warm-hot baryons along the line of sight to distant blazars and of hot gas between interacting clusters. These observations were, however, unable to trace the large-scale filamentary structure, or to estimate the total amount of warm-hot baryons in a representative volume of the Universe. Here we report X-ray observations of filamentary structures of gas at 10(7) kelvin associated with the galaxy cluster Abell 2744. Previous observations of this cluster were unable to resolve and remove coincidental X-ray point sources. After subtracting these, we find hot gas structures that are coherent over scales of 8 megaparsecs. The filaments coincide with over-densities of galaxies and dark matter, with 5-10 per cent of their mass in baryonic gas. This gas has been heated up by the cluster's gravitational pull and is now feeding its core. Our findings strengthen evidence for a picture of the Universe in which a large fraction of the missing baryons reside in the filaments of the cosmic web. PMID:26632589

  13. Seven novel mutations at the 5,10-methylenetetrahydrofolate reductase locus

    SciTech Connect

    Goyette, P.; Frosst, P.; Rosenblatt, D.S.; Rozen, R.

    1994-09-01

    5,10-methylenetetrahydrofolate reductase (MTHFR), a flavoprotein, catalyzes the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, a cofactor for methionine synthase in the methylation of homocysteine to methionine. Severe MTHFR deficiency, which causes homocysteinemia, is an autosomal recessive disorder with variable clinical features; developmental delay, perinatal death, mental retardation and asymptomatic individuals have been observed. A milder deficiency has been reported in patients with cardiovascular disease. We have recently described the isolation of a cDNA for MTHFR and the identification of 2 mutations in patients with severe MTHFR deficiency. We report here the characterization of 7 additional mutations at this locus: 5 missense mutations and 2 splicing mutations. Mutation analysis was performed by SSCP on PCR products generated either from reverse transcription-PCR of patients` total fibroblast RNA or from PCR of patients` genomic DNA. The 5 missense mutations are as follows: 1 Arg to Cys substitution in a hydrophilic segment proposed to be the hinge region that connects the catalytic and regulatory domains, 2 different Arg to Cys substitutions in 2 patients whose enzymatic thermolability is responsive to FAD, 1 Thr to Met substitution affecting an evolutionarily-conserved residue and a Pro to Leu substitution. The 2 splicing mutations affect the 5{prime} splice site and the 3{prime} splice site of 2 introns, respectively. The 5{prime} splice site mutation generates a 57 bp in-frame deletion of the RNA through the utilization of a cryptic 5{prime} splice site within the coding sequence. The identification of 9 mutations at this locus has allowed us to make preliminary correlations between genotype and phenotype and to contribute to a structure:function analysis of the enzyme.

  14. Warm-hot baryons comprise 5-10 per cent of filaments in the cosmic web.

    PubMed

    Eckert, Dominique; Jauzac, Mathilde; Shan, HuanYuan; Kneib, Jean-Paul; Erben, Thomas; Israel, Holger; Jullo, Eric; Klein, Matthias; Massey, Richard; Richard, Johan; Tchernin, Céline

    2015-12-01

    Observations of the cosmic microwave background indicate that baryons account for 5 per cent of the Universe's total energy content. In the local Universe, the census of all observed baryons falls short of this estimate by a factor of two. Cosmological simulations indicate that the missing baryons have not condensed into virialized haloes, but reside throughout the filaments of the cosmic web (where matter density is larger than average) as a low-density plasma at temperatures of 10(5)-10(7) kelvin, known as the warm-hot intergalactic medium. There have been previous claims of the detection of warm-hot baryons along the line of sight to distant blazars and of hot gas between interacting clusters. These observations were, however, unable to trace the large-scale filamentary structure, or to estimate the total amount of warm-hot baryons in a representative volume of the Universe. Here we report X-ray observations of filamentary structures of gas at 10(7) kelvin associated with the galaxy cluster Abell 2744. Previous observations of this cluster were unable to resolve and remove coincidental X-ray point sources. After subtracting these, we find hot gas structures that are coherent over scales of 8 megaparsecs. The filaments coincide with over-densities of galaxies and dark matter, with 5-10 per cent of their mass in baryonic gas. This gas has been heated up by the cluster's gravitational pull and is now feeding its core. Our findings strengthen evidence for a picture of the Universe in which a large fraction of the missing baryons reside in the filaments of the cosmic web.

  15. Simulation using HYDRUS-2D for Soil Water and Heat Transfer under Drip Irrigation with 95oC Hot Water

    NASA Astrophysics Data System (ADS)

    Ito, Y.; Noborio, K.

    2015-12-01

    In Japan, soil disinfection with hot water has been popular since the use of methyl bromide was restricted in 2005. Decreasing the amount of hot water applied may make farmers reduce the operation cost. To determine the appropriate amount of hot water needed for soil disinfection, HYDRUS-2D was evaluated. A field experiment was conducted and soil water content and soil temperature were measured at 5, 10, 20, 40, 60, 80 and 100 cm deep when 95oC hot water was applied. Irrigation tubing equipped with drippers every 30 cm were laid at the soil surface, z=0 cm. An irrigation rate for each dripper was 0.83 cm min-1 between t=0 and 120 min, and thereafter it was zero. Temperature of irrigation water was 95oC. Total simulation time with HYDRUS-2D was 720 min for a homogeneous soil. A simulating domain was selected as x=60 cm and z=100 cm. A potential evaporation rate was assumed to be 0 cm min-1 because the soil surface was covered with a plastic sheet. The boundary condition at the bottom was free drainage and those of both sides were no-flux conditions. Hydraulic properties and bulk densities measured at each depth were used for simulation. It was assumed that there was no organic matter contained. Soil thermal properties were adopted from previous study and HYDRUS 2D. Simulated temperatures at 5, 10, 20 and 40 cm deep agreed well with those measured although simulated temperatures at 60, 80, and 100 cm deep were overly estimated. Estimates of volumetric water content at 5 cm deep agreed well with measured values. Simulated values at 10 to 100 cm deep were overly estimated by 0.1 to 0.3 (m3 m-3). The deeper the soil became, the more the simulated wetting front lagged behind the measured one. It was speculated that water viscosity estimated smaller at high temperature might attributed to the slower advances of wetting front simulated with HYDRUS 2-D.

  16. Frozen soil parameterization in a distributed biosphere hydrological model

    NASA Astrophysics Data System (ADS)

    Wang, L.; Koike, T.; Yang, K.; Jin, R.; Li, H.

    2010-03-01

    In this study, a frozen soil parameterization has been modified and incorporated into a distributed biosphere hydrological model (WEB-DHM). The WEB-DHM with the frozen scheme was then rigorously evaluated in a small cold area, the Binngou watershed, against the in-situ observations from the WATER (Watershed Allied Telemetry Experimental Research). First, by using the original WEB-DHM without the frozen scheme, the land surface parameters and two van Genuchten parameters were optimized using the observed surface radiation fluxes and the soil moistures at upper layers (5, 10 and 20 cm depths) at the DY station in July. Second, by using the WEB-DHM with the frozen scheme, two frozen soil parameters were calibrated using the observed soil temperature at 5 cm depth at the DY station from 21 November 2007 to 20 April 2008; while the other soil hydraulic parameters were optimized by the calibration of the discharges at the basin outlet in July and August that covers the annual largest flood peak in 2008. With these calibrated parameters, the WEB-DHM with the frozen scheme was then used for a yearlong validation from 21 November 2007 to 20 November 2008. Results showed that the WEB-DHM with the frozen scheme has given much better performance than the WEB-DHM without the frozen scheme, in the simulations of soil moisture profile at the cold regions catchment and the discharges at the basin outlet in the yearlong simulation.

  17. Detection of Thermal 2 cm and 1 cm Formaldehyde Emission in NGC 7538

    NASA Astrophysics Data System (ADS)

    Yuan, Liang; Araya, E. D.; Hofner, P.; Kurtz, S.; Pihlstrom, Y.

    2011-05-01

    Formaldehyde is a tracer of high density gas in massive star forming regions. The K-doublet lines from the three lowest rotational energy levels of ortho-formaldehyde correspond to wavelengths of 6, 2 and 1 cm. Thermal emission of these transitions is rare, and maser emission has only been detected in the 6 cm line. NGC 7538 is an active site of massive star formation in the Galaxy, and one of only a few regions known to harbor 6 cm formaldehyde (H2CO) masers. Using the NRAO 100 m Green Bank Telescope (GBT), we detected 2 cm H2CO emission toward NGC 7538 IRS1. The velocity of the 2 cm H2CO line is very similar to the velocity of one of the 6 cm H2CO masers but the linewidth is greater. To investigate the nature of the 2 cm emission, we conducted observations of the 1 cm H2CO transition, and obtained a cross-scan map of the 2 cm line. We detected 1 cm emission and found that the 2 cm emission is extended (greater than 30"), which implies brightness temperatures of ˜0.2 K. Assuming optically thin emission, LTE, and that the 1 cm and 2 cm lines originate from the same volume of gas, both these detections are consistent with thermal emission of gas at ˜30 K. We conclude that the 1 cm and 2 cm H2CO lines detected with the GBT are thermal, which implies molecular densities above ˜105 cm-3. LY acknowledges support from WIU. PH acknowledges partial support from NSF grant AST-0908901.

  18. [Effects of tillage conversion on carbon sequestration capability of farmland soil doubled cropped with wheat and corn].

    PubMed

    Han, Bin; Kong, Fan-Lei; Zhang, Hai-Lin; Chen, Fu

    2010-01-01

    By the methods of field experiment, laboratory analysis, and in situ investigation, this paper studied the effects of different tillage conversion on the carbon sequestration capability of farmland soil doubled cropped with wheat and corn. Compared with conventional tillage (CTA), conservation tillage practices benefited the accumulation of soil organic carbon, among which, no-tillage plus straw returning (NTS) increased the organic carbon accumulation in 0-5 cm soil layer by 18.0%, rotary tillage plus straw returning (RTS) increased this accumulation in 0-5 and 5-10 cm soil layers by 17.6% and 25.0%, respectively, and conventional tillage plus straw returning (CTS) increased the organic carbon in 10-30 cm soil layer by 31.8%. After the conversion from CTA to NTS, the carbon emission from farm operations decreased by 54.3 kg x hm(-2) x a(-1); while the conversion from CTA to CTS and RTS resulted in an increase of this emission by 46.9 kg x hm(-2) x a(-1) and 34.4 kg x hm(-2) x a(-1), respectively. Considering of the accumulation of soil organic carbon and the carbon emission from farm operations, it could be concluded that the conversion from CTA to conservation tillage changed this farmland soil from carbon source to carbon sink, and the RTS among the three conservation tillage modes resulted in the highest soil carbon sequestration (1011.1 kg x hm(-2) x a(-1)).

  19. Estimation of Soil Organic Carbon Stock in the Midtre Lovénbreen Moraine, Svalbard

    NASA Astrophysics Data System (ADS)

    Jung, J. Y.; Lee, Y. K.; Kwon, H.; Kim, S. E.; Laffly, D.; Le NIR, Y.; Nilsen, L.; Moreau, M.

    2014-12-01

    As a glacier retreats, land surface beneath the glacier is newly exposed, and changes in soil have initiated as well as microbial and plants species. Numerous studies have been done on soil development along the chronosequence in the glacier moraine, and mostly undisturbed areas were selected as sampling sites to represent soil age well. However, the surface of glacier moraine is remodeled by active flows, and terrain attributes are very diverse, thus soil organic carbon (SOC) accumulation is not always a linear function of soil age in the glacier moraine. Therefore, we examined the distribution of SOC in the Midtre Lovénbreen morain with a consideration of soil age, microtopography, and runoff activity in this study. Forty two soil sampling sites were selected among previously observed 300 points of plant species via the systematic random sampling method with a consideration of soil age, runoff activities, slope, aspect, and X, Y coordinates. Three close to the glacier terminus and nine sites outside of moraine were additionally sampled. Four different depths (0-5, 5-10, 10-20, and 20-30 cm) of soil were collected, and soil volume was measured by the excavation method in summer 2014. Currently, we are in a status of acquiring microtopographic information from digital elevation model, calculating bulk density, and preparing soil samples for SOC analysis. Once we gather all data, corresponding analysis and classification will be conducted to characterize sampling sites. Then, SOC distribution over the glacier moraine using microtopographic information will be estimated through modelling.

  20. Soil biochemical properties of grassland ecosystems under anthropogenic emission of nitrogen compounds

    NASA Astrophysics Data System (ADS)

    Kudrevatykh, Irina; Ivashchenko, Kristina; Ananyeva, Nadezhda

    2016-04-01

    Inflow of pollutants in terrestrial ecosystems nowadays increases dramatically, that might be led to disturbance of natural biogeochemical cycles and landscapes structure. Production of nitrogen fertilizers is one of the air pollution sources, namely by nitrogen compounds (NH4+, NO3-, NO2-). Air pollution by nitrogen compounds of terrestrial ecosystems might be affected on soil biochemical properties, which results increasing mineral nitrogen content in soil, changing soil P/N and Al/Ca ratios, and, finally, the deterioration of soil microbial community functioning. The research is focused on the assessment of anthropogenic emission of nitrogen compounds on soil properties of grassland ecosystems in European Russia. Soil samples (Voronic Chernozem Pachic, upper 10 cm mineral layer, totally 10) were taken from grassland ecosystem: near (5-10 m) nitrogen fertilizer factory (NFF), and far from it (20-30 km, served as a control) in Tula region. In soil samples the NH4+ and NO3- (Kudeyarov's photocolorimetric method), P, Ca, Al (X-ray fluorescence method) contents were measured. Soil microbial biomass carbon (Cmic) was analyzed by substrate-induced respiration method. Soil microbial respiration (MR) was assessed by CO2 rate production. Soil microbial metabolic quotient (qCO2) was calculated as MR/Cmic ratio. Near NFF the soil ammonium and nitrate nitrogen contents were a strongly varied, variation coefficient (CV) was 42 and 86This study was supported by Russian Foundation of Basic Research Grant No. 14-04-00098, 15-44-03220, 15-04-00915.

  1. Probing lepton asymmetry with 21 cm fluctuations

    SciTech Connect

    Kohri, Kazunori; Oyama, Yoshihiko; Sekiguchi, Toyokazu; Takahashi, Tomo E-mail: oyamayo@post.kek.jp E-mail: tomot@cc.saga-u.ac.jp

    2014-09-01

    We investigate the issue of how accurately we can constrain the lepton number asymmetry ξ{sub ν}=μ{sub ν}/T{sub ν} in the Universe by using future observations of 21 cm line fluctuations and cosmic microwave background (CMB). We find that combinations of the 21 cm line and the CMB observations can constrain the lepton asymmetry better than big-bang nucleosynthesis (BBN). Additionally, we also discuss constraints on ξ{sub ν} in the presence of some extra radiation, and show that the 21 cm line observations can substantially improve the constraints obtained by CMB alone, and allow us to distinguish the effects of the lepton asymmetry from the ones of extra radiation.

  2. CV and CM chondrite impact melts

    NASA Astrophysics Data System (ADS)

    Lunning, Nicole G.; Corrigan, Catherine M.; McSween, Harry Y.; Tenner, Travis J.; Kita, Noriko T.; Bodnar, Robert J.

    2016-09-01

    Volatile-rich and typically oxidized carbonaceous chondrites, such as CV and CM chondrites, potentially respond to impacts differently than do other chondritic materials. Understanding impact melting of carbonaceous chondrites has been hampered by the dearth of recognized impact melt samples. In this study we identify five carbonaceous chondrite impact melt clasts in three host meteorites: a CV3red chondrite, a CV3oxA chondrite, and a regolithic howardite. The impact melt clasts in these meteorites respectively formed from CV3red chondrite, CV3oxA chondrite, and CM chondrite protoliths. We identified these impact melt clasts and interpreted their precursors based on their texture, mineral chemistry, silicate bulk elemental composition, and in the case of the CM chondrite impact melt clast, in situ measurement of oxygen three-isotope signatures in olivine. These impact melts typically contain euhedral-subhedral olivine microphenocrysts, sometimes with relict cores, in glassy groundmasses. Based on petrography and Raman spectroscopy, four of the impact melt clasts exhibit evidence for volatile loss: these melt clasts either contain vesicles or are depleted in H2O relative to their precursors. Volatile loss (i.e., H2O) may have reduced the redox state of the CM chondrite impact melt clast. The clasts that formed from the more oxidized precursors (CV3oxA and CM chondrites) exhibit phase and bulk silicate elemental compositions consistent with higher intrinsic oxygen fugacities relative to the clast that formed from a more reduced precursor (CV3red chondrite). The mineral chemistries and assemblages of the CV and CM chondrite impact melt clasts identified here provide a template for recognizing carbonaceous chondrite impact melts on the surfaces of asteroids.

  3. 5,10 Methylenetetrahydrofolate reductase genetic polymorphism as a risk factor for neural tube defects

    SciTech Connect

    Ou, C.Y.; Brown, V.K.; Khoury, M.J.

    1996-06-28

    Persons with a thermolabile form of the enzyme 5,10 methylenetetrahydrofolate reductase (MTHFR) have reduced enzyme activity and increased plasma homocysteine which can be lowered by supplemental folic acid. Thermolability of the enzyme has recently been shown to be caused by a common mutation (677C{sup {r_arrow}}T) in the MTHFR gene. We studied 41 fibroblast cultures from NTD-affected fetuses and compared their genotypes with those of 109 blood specimens from individuals in the general population. 677C{sup {r_arrow}}T homozygosity was associated with a 7.2 fold increased risk for NTDs (95% confidence interval: 1.8-30.3; p value: 0.001). These preliminary data suggest that the 677C{sup {r_arrow}}T polymorphism of the MTHFR gene is a risk factor for spina bifida and anencephaly that may provide a partial biologic explanation for why folic acid prevents these types of NTD. 13 refs., 1 fig., 1 tab.

  4. Folate metabolism gene 5,10-methylenetetrahydrofolate reductase (MTHFR) is associated with ADHD in myelomeningocele patients.

    PubMed

    Spellicy, Catherine J; Northrup, Hope; Fletcher, Jack M; Cirino, Paul T; Dennis, Maureen; Morrison, Alanna C; Martinez, Carla A; Au, Kit Sing

    2012-01-01

    The objective of this study was to examine the relation between the 5, 10-methylenetetrahydrofolate reductase (MTHFR) gene and behaviors related to attention- deficit/hyperactivity disorder (ADHD) in individuals with myelomeningocele. The rationale for the study was twofold: folate metabolizing genes, (e.g. MTHFR), are important not only in the etiology of neural tube defects but are also critical to cognitive function; and individuals with myelomeningocele have an elevated incidence of ADHD. Here, we tested 478 individuals with myelomeningocele for attention-deficit hyperactivity disorder behavior using the Swanson Nolan Achenbach Pelham-IV ADHD rating scale. Myelomeningocele participants in this group for whom DNAs were available were genotyped for seven single nucleotide polymorphisms (SNPs) in the MTHFR gene. The SNPs were evaluated for an association with manifestation of the ADHD phenotype in children with myelomeningocele. The data show that 28.7% of myelomeningocele participants exhibit rating scale elevations consistent with ADHD; of these 70.1% had scores consistent with the predominantly inattentive subtype. In addition, we also show a positive association between the SNP rs4846049 in the 3'-untranslated region of the MTHFR gene and the attention-deficit hyperactivity disorder phenotype in myelomeningocele participants. These results lend further support to the finding that behavior related to ADHD is more prevalent in patients with myelomeningocele than in the general population. These data also indicate the potential importance of the MTHFR gene in the etiology of the ADHD phenotype. PMID:23227261

  5. Characterization of 8-cm engineering model thruster

    NASA Technical Reports Server (NTRS)

    Williamson, W. S.

    1984-01-01

    Development of 8 cm ion thruster technology which was conducted in support of the Ion Auxiliary Propulsion System (IAPS) flight contract (Contract NAS3-21055) is discussed. The work included characterization of thruster performance, stability, and control; a study of the effects of cathode aging; environmental qualification testing; and cyclic lifetesting of especially critical thruster components.

  6. The Multidimensional Curriculum Model (MdCM)

    ERIC Educational Resources Information Center

    Vidergor, Hava E.

    2010-01-01

    The multidimensional Curriculum Model (MdCM) helps teachers to better prepare gifted and able students for our changing world, acquiring much needed skills. It is influenced by general learning theory of constructivism, notions of preparing students for 21st century, Teaching the Future Model, and current comprehensive curriculum models for…

  7. [Effects of different tillage measures on upland soil respiration in Loess Plateau].

    PubMed

    Sun, Xiao-hua; Zhang, Ren-zhi; Cai, Li-qun; Chen, Qiang-qiang

    2009-09-01

    A field experiment was conducted in Lijiabu Town of Dingxi City, Gansu Province to study the soil respiration and its relations with the canopy temperature and soil moisture content in a rotation system with spring wheat and pea under effects of different tillage measures. Six treatments were installed, i.e., tillage with no straw- or plastic mulch (conventional tillage, T), tillage with straw mulch (TS), tillage with plastic mulch (TP), no-tillage (NT), no-tillage with straw mulch (NTS), and no-tillage with plastic mulch (NTP). During the growth periods of spring wheat and pea, soil respiration had different change patterns, with the peaks appeared at the early jointing, grain-filling, and maturing stages of spring wheat, and at the 5-leaf, silking, flowering and poding, in spring wheat field between treatments NTS and T, and the soil respiration rate was significantlyand maturing stages of pea. There was an obvious difference in the diurnal change of soil respiration lower in NTS than in T; while the soil respiration in pea field had less diurnal chan ge. Soil respiration rate had a significant linear relationship with the canopy temperature of both spring wheat andpea, the correlation coefficient being the highest at booting stage of spring wheat and at flowering and poding stage of pea, followed by at grain-filling stage of spring wheat and at branching stage of pea. There was also a significant parabola relationship between soil respiration rate and soil moisture content, the correlation coefficient being higher under conservation tillage than under conventional tillage, with the highest under NTS. The moisture content in 10-30 cm soil layer of spring wheat field and that in 5-10 cm soil layer of pea field had the greatest effects on soil respiration. Comparing with conventional tillage, all the five conservation tillage measures decreased soil respiration, with the best effects of no-tillage with straw mulch.

  8. Substrate specificity of mammalian folylpolyglutamate synthetase for 5,10-dideazatetrahydrofolate analogs.

    PubMed

    Habeck, L L; Mendelsohn, L G; Shih, C; Taylor, E C; Colman, P D; Gossett, L S; Leitner, T A; Schultz, R M; Andis, S L; Moran, R G

    1995-08-01

    The metabolism of 5,10-dideazatetrahydrofolate (DDATHF [lometrexol]) to polyglutamate derivatives by folylpoly-gamma-glutamate synthetase (FPGS) plays a central role in the activity of this compound as an antineoplastic agent. The availability of a series of DDATHF derivatives differing in structure throughout the molecule has allowed a study of the structural requirements for substrate activity with mouse liver and hog liver FPGS. Kinetics of the polyglutamation reaction in vitro have been related to the potency of these compounds as inhibitors of the growth of human CEM leukemic cells. The structure-activity relationships for enzyme from both sources were nearly identical. FPGS from both species showed a broad acceptance for structural changes in the pyridopyrimidine ring, in the phenyl group, and in the intermediate bridge region, with structural changes in these regions being reflected in changes in Km for FPGS but much more modest alterations in Vmax. The data suggested that the phenyl ring was not contributing to any pi-pi hydrophobic interactions. It appeared to function primarily in maintaining a favorable distance between the pyridopyrimidine ring and the glutamate side chain. The lowest Km values were found for DDATHF analogs in which there were small alterations at the 10 position, e.g., 5-deazatetrahydrofolate, 10-methyl-DDATHF, and 10-formyl-5-deazatetrahydrofolate; the first-order rate constants for these substrates were the highest in this series, an indication of the efficiency of polyglutamation at low substrate concentrations. After correction for the intrinsic inhibitory activity of the parent DDATHF analog as an inhibitor of the target enzyme, the first-order rate constants for FPGS were found to be predictive of the potency of tumor cell growth inhibition for most of the compounds in this structural series.

  9. Warm-hot baryons comprise 5-10 per cent of filaments in the cosmic web

    NASA Astrophysics Data System (ADS)

    Eckert, Dominique; Jauzac, Mathilde; Shan, Huanyuan; Kneib, Jean-Paul; Erben, Thomas; Israel, Holger; Jullo, Eric; Klein, Matthias; Massey, Richard; Richard, Johan; Tchernin, Céline

    2015-12-01

    Observations of the cosmic microwave background indicate that baryons account for 5 per cent of the Universe’s total energy content. In the local Universe, the census of all observed baryons falls short of this estimate by a factor of two. Cosmological simulations indicate that the missing baryons have not condensed into virialized haloes, but reside throughout the filaments of the cosmic web (where matter density is larger than average) as a low-density plasma at temperatures of 105-107 kelvin, known as the warm-hot intergalactic medium. There have been previous claims of the detection of warm-hot baryons along the line of sight to distant blazars and of hot gas between interacting clusters. These observations were, however, unable to trace the large-scale filamentary structure, or to estimate the total amount of warm-hot baryons in a representative volume of the Universe. Here we report X-ray observations of filamentary structures of gas at 107 kelvin associated with the galaxy cluster Abell 2744. Previous observations of this cluster were unable to resolve and remove coincidental X-ray point sources. After subtracting these, we find hot gas structures that are coherent over scales of 8 megaparsecs. The filaments coincide with over-densities of galaxies and dark matter, with 5-10 per cent of their mass in baryonic gas. This gas has been heated up by the cluster’s gravitational pull and is now feeding its core. Our findings strengthen evidence for a picture of the Universe in which a large fraction of the missing baryons reside in the filaments of the cosmic web.

  10. Kokes Awards for the 22nd North American Catalysis Society Meeting, June 5-10, 2011

    SciTech Connect

    Fabio H. Ribeiro

    2011-06-05

    The biennial North American Catalysis Society (NACS) Meetings are the premiere conferences in the area of catalysis, surface science, and reaction engineering. The 22nd meeting will be held the week of June 5-10, 2011 in Detroit, Michigan. The objective of the Meetings is to bring together leading researchers for intensive scientific exchange and interactions. Financial support that offsets some of the associated costs (specifically, registration fee, airline tickets, and hotel accommodations) would encourage graduate students, and for the first time undergraduate students, to attend and participate meaningfully in this conference. The funds sought in this proposal will help support the Richard J. Kokes Travel Award program. Graduate students eligible for these merit-based Awards are those who study at a North American university and who will present at the Meeting. We have currently 209 applications and we expect to be able to fund about half of them. The NACS has traditionally sought to encourage graduate student, and this year for the first time undergraduate studies, participation at the National Meetings and providing financial support is the most effective means to do so. Their attendance would contribute significantly to their scientific training and communication and presentation skills. They would be exposed to the leading researchers from the US and abroad; they would meet their peers from other universities; they would learn about cutting-edge results that could benefit their research projects; and they may become interested in becoming active participants in the catalysis community. These young investigators represent the next generation of scientists and engineers, and their proper training will lead to future scientific breakthroughs and technological innovations that benefit the US economy. Advances in catalysis can come in the form of more energy-efficient and environmentally-friendly chemical processes, improved fuel cell performance, efficient

  11. Measurements of Output Factors For Small Photon Fields Up to 10 cm x 10 cm

    NASA Astrophysics Data System (ADS)

    Bacala, Angelina

    Field output factors (OF) for photon beams from a 6 MV medical accelerator were measured using five different detectors in a scanning water phantom. The measurements were taken for square field sizes of integral widths ranging from 1 cm to 10 cm for two reference source-to-surface distances (SSD) and depths in water. For the diode detectors, square field widths as small as 2.5 mm were also studied. The photon beams were collimated by using either the jaws or the multileaf collimators. Measured OFs are found to depend upon the field size, SSD, depth and also upon the type of beam collimation, size and type of detector used. For field sizes larger than 3 cm x 3 cm, the OF measurements agree to within 1% or less. The largest variation in OF occurs for jawsshaped field of size 1 cm x 1cm, where a difference of more than 18% is observed.

  12. Soil respiration in a long-term tillage treatment experiment

    NASA Astrophysics Data System (ADS)

    Gelybó, Györgyi; Birkás, Márta; Dencsö, Márton; Horel, Ágota; Kása, Ilona; Tóth, Eszter

    2016-04-01

    Regular soil CO2 efflux measurements have been carried out at Józsefmajor longterm tillage experimental site in 2014 and 2015 with static chamber technique in no-till and ploughing plots in seven spatial replicates. The trial was established in 2002 on a loamy chernozem soil at the experimental site of the Szent István University nearby the city Hatvan, northern Hungary. At the site sunflower (Helianthus A.) and wheat (Triticum A.) was grown in 2014 and 2015, respectively. Ancillary measurements carried out at the site included weather parameters, soil water content, soil temperature. The aim of the investigation was to detect the effect of soil disturbance and soil tillage treatments on soil CO2 emission in agricultural ecosystems. Soil respiration measurements were carried out every week during the vegetation period and campaign measurements were performed scheduled to tillage application. In this latter case, measurements were carried out 1, 2, 3, 4, 6, 12, 18, 24, 48, 72, 96, 120 hours and 7 days after tillage operation. Results showed that during the vegetation season in the majority of measurement occasions emission was higher in the no-till plots. These differences; however were not found to be statistically significant. Due to the short term effect of tillage treatment, emissions increased following tillage treatment in the ploughed plots. Soil water content was also examined as main driver of soil CO2 fluxes. Soil water content sharply decreases in the surface layer (5-10 cm depth) after tillage treatment indicating a fast drying due to soil disturbance. This effect slowly attenuated and eventually extincted in approx. two weeks. CO2 emission measurements were associated with high uncertainties as a result of the measurement technique. Our further aim is to reduce this uncertainty using independent measurement techniques on the field.

  13. Interpreting Sky-Averaged 21-cm Measurements

    NASA Astrophysics Data System (ADS)

    Mirocha, Jordan

    2015-01-01

    Within the first ~billion years after the Big Bang, the intergalactic medium (IGM) underwent a remarkable transformation, from a uniform sea of cold neutral hydrogen gas to a fully ionized, metal-enriched plasma. Three milestones during this epoch of reionization -- the emergence of the first stars, black holes (BHs), and full-fledged galaxies -- are expected to manifest themselves as extrema in sky-averaged ("global") measurements of the redshifted 21-cm background. However, interpreting these measurements will be complicated by the presence of strong foregrounds and non-trivialities in the radiative transfer (RT) modeling required to make robust predictions.I have developed numerical models that efficiently solve the frequency-dependent radiative transfer equation, which has led to two advances in studies of the global 21-cm signal. First, frequency-dependent solutions facilitate studies of how the global 21-cm signal may be used to constrain the detailed spectral properties of the first stars, BHs, and galaxies, rather than just the timing of their formation. And second, the speed of these calculations allows one to search vast expanses of a currently unconstrained parameter space, while simultaneously characterizing the degeneracies between parameters of interest. I find principally that (1) physical properties of the IGM, such as its temperature and ionization state, can be constrained robustly from observations of the global 21-cm signal without invoking models for the astrophysical sources themselves, (2) translating IGM properties to galaxy properties is challenging, in large part due to frequency-dependent effects. For instance, evolution in the characteristic spectrum of accreting BHs can modify the 21-cm absorption signal at levels accessible to first generation instruments, but could easily be confused with evolution in the X-ray luminosity star-formation rate relation. Finally, (3) the independent constraints most likely to aide in the interpretation

  14. Fractal features of soil properties distribution in an urban park - a case study: Bar-Ilan University campus, Ramat-Gan, Israel

    NASA Astrophysics Data System (ADS)

    Zhevelev, Helena; Sarah, Pariente

    2014-05-01

    Green open spaces in the city include campuses of various institutions. Their physical and sociological functions are similar to those of urban parks, and the present study was conducted in the campus of Bar-Ilan University. It aimed to detect the features of the distributions of several ecological properties, as affected by various land cover components and their associated microenvironments. For this purpose, three types of microenvironments, representative of the campus were chosen. They were: under the canopies of nine species of trees; lawns (disturbed and undisturbed); and paths. In each microenvironment, soil was sampled from two layers (0-2 and 5-10 cm), soil temperatures were measured at depths down to 10 cm (0, 1, 2, 4, 6, 8, 10 cm), and air temperatures were recorded at heights up to 160 cm (30, 60, 100, 160 cm). For each soil sample, soil moisture and organic matter contents were determined in December 2011 and March 2012. Before the samplings, penetration depth was measured. From December to March soil penetration depths and soil moisture contents decreased by 30-50%. In contrast, organic matter content increased from 0.5 to 1.5% in all microenvironments. In December there were no differences in soil temperatures among the microenvironments, but in March differences of 4-5 C° were found. Highest soil temperatures, at all depths, were found in the Lawn and Path microenvironments. For all the various microenvironments, at each depth, the distributions by percentiles (deciles, medians and quartiles) of all soil properties were calculated and analyzed. Highly significant linear correlations between percentiles and averages of soil properties were found for all the microenvironments and at both depths. Thus, the soil properties of the Bar-Ilan University campus exhibited a fractal structure.

  15. Rapid transport and transformation of phosphorus species during the leaching of poultry manure amended soil

    NASA Astrophysics Data System (ADS)

    Giles, Courtney; Cade-Menun, Barbara; Liu, Corey; Hill, Jane

    2015-04-01

    The loss of phosphorus (P) from soils due to leaching is a major concern in heavily fertilized agricultural regions. The mobility and transformation of P species will depend on the source of manure fertilizer, leaching regime, and the extent of soil P saturation within the soil profile. We investigate spatial and temporal changes in the distribution of P species within a poultry manure-amended soil at two depths (0-5, 10-15 cm) as well as leachate P fractions during 10 weeks of leaching. Leachate P was primarily composed of dissolved fractions (soluble reactive P; dissolved unreactive P) and reached a maximum in the fourth week of leaching. In soils, the degree of P saturation (80%) and water extractable P (9 mg kg-1) were also greatest in week 4. 31P NMR spectra of the 0-5 cm depth indicate that surface soils were most similar to the poultry manure in week 4. During peak leaching, the proportion of orthophosphate (OrthoP) at the soil surface (0-5 cm; 80%) was greater than that from the lowest depth (10-15 cm; 72%), which contained relatively larger proportions of monoester-(17%) and diester-P classes (10%). Poultry manure likely contributed to the mobile pool of P species, including OrthoP, myo-inositol hexakisphosphate (myo-IHP), and nucleic acids. The appearance of neo- and D-chiro-IHP, as well as phospholipid signals during the leaching period indicate possible short-term (<10 week) contributions of organic P to the generation and leaching of OrthoP, under P-saturated conditions. Further work is needed to determine how fertilization and leaching will affect the mobility and transformation of P species across a wider range of soil types. Keywords: Phytate, organic phosphorus, degree of phosphorus saturation, soil, leachate, poultry manure

  16. Balloon observations of the radiance of the earth between 2100 cm(-1) and 2700 cm(-1).

    PubMed

    Shaw, J H; McClatchey, R A; Schaper, P W

    1967-02-01

    A grating spectrometer capable of measuring small radiation fluxes with a spectral resolution of 95 at 4.3 micro is described. Bands of CO(2), N(2)O, and O(3) are identified in spectra between 2100 cm(-1) and 2700 cm(-1) of the earth and lower atmosphere obtained from an altitude of 30 km with this instrument. Scattering of solar radiation by clouds was observed between 2400 cm(-1) and 2700 cm(-1). A temperature profile of the atmosphere to 30 km determined from an analysis of the measurements in the region of the 4.3 micro CO(2) band is compared with radiosonde observations made during the flight.

  17. Hydrogen-Broadened Water from 50 to 300 cm-1 and 1300 to 4000 cm-1

    NASA Technical Reports Server (NTRS)

    Brown, L.; Peterson, D.; Plymate, C.

    1995-01-01

    To support remote sensing of the outer planets, absorption spectra of H2O broadened by H2 were recorded at room temperature using two Fourier transform spectrometers. The data from 1300 to 4000 cm-1 were obtained at 0.012 cm-1 resolution with the McMath FTS located at Kitt Peak National Observatory/National Solar Observatory. The remainder of the spectral data from 55 to 320 cm-1 were taken at 0.0056 cm-1 with the Bruker FTS.

  18. Magnetic susceptibility of curium pnictides. [/sup 248/CmP, /sup 248/CmSb

    SciTech Connect

    Nave, S.E.; Huray, P.G.; Peterson, J.R.; Damien, D.A.; Haire, R.G.

    1981-09-01

    The magnetic susceptibility of microgram quantities of /sup 248/CmP and /sup 248/CmSb has been determined with the use of a SQUID micromagnetic susceptometer over the temperature range 4.2 to 340 K and in the applied magnetic field range of 0.45 to 1600 G. The fcc (NaCl-type) samples yield magnetic transitions at 73K and 162 K for the phosphide and antimonide, respectively. Together with published magnetic data for CmN and CmAs, these results indicate spatially extended exchange interactions between the relatively localized 5f electrons of the metallic actinide atoms.

  19. Extended Performance 8-cm Mercury Ion Thruster

    NASA Technical Reports Server (NTRS)

    Mantenieks, M. A.

    1981-01-01

    A slightly modified 8-cm Hg ion thruster demonstrated significant increase in performance. Thrust was increased by almost a factor of five over that of the baseline thruster. Thruster operation with various three grid ion optics configurations; thruster performance as a function of accelerator grid open area, cathode baffle, and cathode orifice size; and a life test of 614 hours at a beam current of 250 mA (17.5 mN thrust) are discussed. Highest thruster efficiency was obtained with the smallest open area accelerator grid. The benefits in efficiency from the low neutral loss grids were mitigated, however, by the limitation such grids place on attainable ion beam current densities. The thruster components suffered negligible weight losses during a life test, which indicated that operation of the 8-cm thruster at extended levels of thrust and power is possible with no significant loss of lifetime.

  20. Sleuthing for drivers of particulate organic matter chemical fingerprints: Effects of land use history and soil heterogeneity in the winegrape region of Napa, CA

    NASA Astrophysics Data System (ADS)

    Yu, O. T.; Calderon, F. J.; Greenhut, R. F.; Hollander, A. D.; O'Geen, A.; Burns, K. N.; Steenwerth, K. L.

    2013-12-01

    Quantity and quality of soil organic matter (SOM, whole soil) and particulate organic matter (POM) fractions may reflect land use history and soil heterogeneity. Attributes of soil heterogeneity like soil mineralogy and texture serve as crucial components in stabilizing SOM, especially the fine fraction (<53 μm) associated with clay minerals. Recent advances in technology (e.g., Fourier Transform Infrared Spectroscopy, FTIR) have allowed better characterization of SOM chemical profiles, or fingerprints. Here, we investigate the combined roles of soil management, land use history and soil heterogeneity on content POM and SOM and chemical fingerprints of SOM and silt/clay-associated OM to reveal how agricultural practices influence soil carbon balance in Mediterranean climates. Soils of a winegrape growing region (Napa, California) were formed into eight clusters by Partitioning Around Medoids (PAM), using existing datasets from NRCS SoilWeb for soil great group, texture class, aspect, slope, elevation, irradiation, and soil organic matter. At least three vineyards (three locations per vineyard) of each soil cluster type were surveyed for soil attributes (pH, exchangeable cations, cation exchange capacity, texture, SOM, POM, TOC, DON; n = 72 sampled locations). The chemical fingerprints of SOM and silt/clay associated-OM (<53 μm; 0-5 cm and 5-10 cm in depth) were measured by FTIR. Current management and land use history were gathered through interviews with vineyard managers. Soil mineralogy was determined by x-ray diffraction (XRD). Data trends suggest that drivers (any natural or human-induced factor that causes a change) of the chemical fingerprints were linked to management practices and land use history, whereas content was strongly linked to soil heterogeneity and mineralogy. Using vineyards as the model system, these data establish the framework for a comprehensive study linking agricultural landscape attributes to processes directing SOM stabilization

  1. 15 cm multipole gas ion thruster

    NASA Technical Reports Server (NTRS)

    Isaacson, G. C.; Kaufman, H. R.

    1976-01-01

    A 15-cm multipole thruster was operated on argon and xenon. The multipole approach used has been shown capable of low discharge losses and flat ion beam profiles with a minimum of redesign. This approach employs low magnetic field strengths and flat or cylindrical sheet-metal parts, hence is suited to rapid optimization and scaling. Only refractory metal cathodes were used in this investigation.

  2. Late type close binary system CM Dra

    NASA Astrophysics Data System (ADS)

    Kalomeni, Belinda

    2015-08-01

    In this study, we present new observations of the close binary system CM Dra. We analyzed all the available data of the system and estimated the physical parameters of the system stars highly accurately. Using the newly obtained parameters the distance of the system is determined to be 11.6 pc. A possible giant planet orbiting the close binary system has been detected. This orbital period would likely make it one of the longest known orbital period planet.

  3. Constraining dark matter through 21-cm observations

    NASA Astrophysics Data System (ADS)

    Valdés, M.; Ferrara, A.; Mapelli, M.; Ripamonti, E.

    2007-05-01

    Beyond reionization epoch cosmic hydrogen is neutral and can be directly observed through its 21-cm line signal. If dark matter (DM) decays or annihilates, the corresponding energy input affects the hydrogen kinetic temperature and ionized fraction, and contributes to the Lyα background. The changes induced by these processes on the 21-cm signal can then be used to constrain the proposed DM candidates, among which we select the three most popular ones: (i) 25-keV decaying sterile neutrinos, (ii) 10-MeV decaying light dark matter (LDM) and (iii) 10-MeV annihilating LDM. Although we find that the DM effects are considerably smaller than found by previous studies (due to a more physical description of the energy transfer from DM to the gas), we conclude that combined observations of the 21-cm background and of its gradient should be able to put constrains at least on LDM candidates. In fact, LDM decays (annihilations) induce differential brightness temperature variations with respect to the non-decaying/annihilating DM case up to ΔδTb = 8 (22) mK at about 50 (15) MHz. In principle, this signal could be detected both by current single-dish radio telescopes and future facilities as Low Frequency Array; however, this assumes that ionospheric, interference and foreground issues can be properly taken care of.

  4. Polyhedral Serpentine Grains in CM Chondrites

    NASA Technical Reports Server (NTRS)

    Zega, Thomas J.; Garvie, Laurence A. J.; Dodony, Istvan; Stroud, Rhonda M.; Buseck, Peter R.

    2005-01-01

    CM chondrites are primitive rocks that experienced aqueous alteration in the early solar system. Their matrices and fine-grained rims (FGRs) sustained the effects of alteration, and the minerals within them hold clues to the aqueous reactions. Sheet silicates are an important product of alteration, and those of the serpentine group are abundant in the CM2 chondrites. Here we expand on our previous efforts to characterize the structure and chemistry of serpentines in CM chondrites and report results on a polyhedral form that is structurally similar to polygonal serpentine. Polygonal serpentine consists of tetrahedral (T) sheets joined to M(2+)-centered octahedral (O) sheets (where (M2+) is primarily Mg(2+) and Fe(2+)), which give rise to a 1:1 (TO) layered structure with a 0.7-nm layer periodicity. The structure is similar to chrysotile in that it consists of concentric lizardite layers wrapped around the fiber axis. However, unlike the rolled-up chrysotile, the tetrahedral sheets of the lizardite layers are periodically inverted and kinked, producing sectors. The relative angles between sectors result in 15- and 30-sided polygons in terrestrial samples.

  5. Lead distribution in soils impacted by a secondary lead smelter: Experimental and modelling approaches.

    PubMed

    Schneider, Arnaud R; Cancès, Benjamin; Ponthieu, Marie; Sobanska, Sophie; Benedetti, Marc F; Pourret, Olivier; Conreux, Alexandra; Calandra, Ivan; Martinet, Blandine; Morvan, Xavier; Gommeaux, Maxime; Marin, Béatrice

    2016-10-15

    Smelting activities are one of the most common sources of trace elements in the environment. The aim of this study was to determine the lead distribution in upper horizons (0-5 and 5-10cm) of acidic soils in the vicinity of a lead-acid battery recycling plant in northern France. The combination of chemical methods (sequential extractions), physical methods (Raman microspectroscopy and scanning electron microscopy with an energy dispersive spectrometer) and multi-surface complexation modelling enabled an assessment of the behaviour of Pb. Regardless of the studied soil, none of the Pb-bearing phases commonly identified in similarly polluted environments (e.g., anglesite) were observed. Lead was mainly associated with organic matter and manganese oxides. The association of Pb with these soil constituents can be interpreted as evidence of Pb redistribution in the studied soils following smelter particle deposition.

  6. The spatiotemporal characteristics of soil physio-chemical parameters and their influence on cotton growth under mulched drip irrigation

    NASA Astrophysics Data System (ADS)

    Hu, H.; Tian, F.; Zhang, Z.; Hu, H.

    2013-12-01

    The spatiotemporal characteristics of the physio-chemical parameters of soil and their impacts on crop growth are the key issues affecting precision agriculture. However, quantitative research in cotton fields under mulched drip irrigation is rare. One hundred experimental plots (6 m× 6 m) were set up for the above purpose in an agricultural experimental field in Xinjiang Uygur Autonomous Region of China. Soil samples were collected to measure the soil texture, moisture and salinity at depths of 5, 10, 20, 30, 50 and 80 cm in the near-tape zone and the inter-film zone in each experimental plot in March, April, June and September of 2012. The number and height of the cotton plants in June and the yield of cotton in September were also surveyed in 3 sample units (75 cm × 75 cm) in each experimental plot. The results indicate that the soil composition of clay and silt was highest at a soil depth of 5 to 20 cm due to the cultivation practices, and the Cv (coefficient of variation) values of soil texture increased with depth. The spring flush led to an 8% decrease in soil salinity and reduced the Cv values of soil salinity, soil moisture and soil texture. The Cv values of soil salinity and soil moisture increased as mulched drip irrigation was applied. The Cv values of soil salinity and moisture under the near tape zone were higher than under the interfilm zone; the difference was up to twofold in September. The validity of a theoretical semivariogram model of soil moisture is greater than that of texture, soil salinity and crop trait when comparing the estimation of the theoretical semivariogram with measured values. The influence of soil physiochemical characteristics on the number of cotton plants is largest in April, and their influence on the height of cotton plants is greatest in June. However, the influence of soil physiochemical characteristics on cotton yield is smaller than that on cotton number and height in April and June. The soil salt under the near tape

  7. Effects of variation in precipitation on the distribution of soil bacterial diversity in the primitive Korean pine and broadleaved forests.

    PubMed

    Wang, Nannan; Wang, Meiju; Li, Shilan; Sui, Xin; Han, Shijie; Feng, Fujuan

    2014-11-01

    Patterns of precipitation have changed as a result of climate change and will potentially keep changing in the future. Therefore, it is critical to understand how ecosystem processes will respond to the variation of precipitation. However, compared to aboveground processes, the effects of precipitation change on soil microorganisms remain poorly understood. Changbai Mountain is an ideal area to study the responses of temperate forests to the variations in precipitation. In this study, we conducted a manipulation experiment to simulation variation of precipitation in the virgin, broad-leaved Korean pine mixed forest in Changbai Mountain. Plots were designed to increase precipitation by 30 % [increased (+)] or decrease precipitation by 30 % [decreased (-)]. We analyzed differences in the diversity of the bacterial community in surface bulk soils (0-5 and 5-10 cm) and rhizosphere soils between precipitation treatments, including control. Bacteria were identified using the high-throughput 454 sequencing method. We obtained a total 271,496 optimized sequences, with a mean value of 33,242 (±1,412.39) sequences for each soil sample. Being the same among the sample plots with different precipitation levels, the dominant bacterial communities were Proteobacteria, Acidobacteria, Actinobacteria, Planctomycetes, and Chloroflexi. Bacterial diversity and abundance declined with increasing soil depth. In the bulk soil of 0-5 cm, the bacterial diversity and abundance was the highest in the control plots and the lowest in plots with reduced precipitation. However, in the soil of 5-10 cm, the diversity and abundance of bacteria was the highest in the plots of increased precipitation and the lowest in the control plots. Bacterial diversity and abundance in rhizosphere soils decreased with increased precipitation. This result implies that variation in precipitation did not change the composition of the dominant bacterial communities but affected bacterial abundance and the response

  8. Decay Data Evaluation Project (DDEP): evaluation of the main 243Cm and 245Cm decay characteristics.

    PubMed

    Chechev, Valery P

    2012-09-01

    The results of new decay data evaluations are presented for (243)Cm (α) decay to nuclear levels in (239)Pu and (245)Cm (α) decay to nuclear levels in (241)Pu. These evaluated data have been obtained within the Decay Data Evaluation Project using information published up to 2011.

  9. The 5-10 keV AGN luminosity function at 0.01 < z < 4.0

    NASA Astrophysics Data System (ADS)

    Fotopoulou, S.; Buchner, J.; Georgantopoulos, I.; Hasinger, G.; Salvato, M.; Georgakakis, A.; Cappelluti, N.; Ranalli, P.; Hsu, L. T.; Brusa, M.; Comastri, A.; Miyaji, T.; Nandra, K.; Aird, J.; Paltani, S.

    2016-03-01

    The active galactic nuclei (AGN) X-ray luminosity function traces actively accreting supermassive black holes and is essential for the study of the properties of the AGN population, black hole evolution, and galaxy-black hole coevolution. Up to now, the AGN luminosity function has been estimated several times in soft (0.5-2 keV) and hard X-rays (2-10 keV). AGN selection in these energy ranges often suffers from identification and redshift incompleteness and, at the same time, photoelectric absorption can obscure a significant amount of the X-ray radiation. We estimate the evolution of the luminosity function in the 5-10 keV band, where we effectively avoid the absorbed part of the spectrum, rendering absorption corrections unnecessary up to NH ~ 1023 cm-2. Our dataset is a compilation of six wide, and deep fields: MAXI, HBSS, XMM-COSMOS, Lockman Hole, XMM-CDFS, AEGIS-XD, Chandra-COSMOS, and Chandra-CDFS. This extensive sample of ~1110 AGN (0.01 < z < 4.0, 41 < log Lx < 46) is 98% redshift complete with 68% spectroscopic redshifts. For sources lacking a spectroscopic redshift estimation we use the probability distribution function of photometric redshift estimation specifically tuned for AGN, and a flat probability distribution function for sources with no redshift information. We use Bayesian analysis to select the best parametric model from simple pure luminosity and pure density evolution to more complicated luminosity and density evolution and luminosity-dependent density evolution (LDDE). We estimate the model parameters that describe best our dataset separately for each survey and for the combined sample. We show that, according to Bayesian model selection, the preferred model for our dataset is the LDDE. Our estimation of the AGN luminosity function does not require any assumption on the AGN absorption and is in good agreement with previous works in the 2-10 keV energy band based on X-ray hardness ratios to model the absorption in AGN up to redshift three

  10. Influence of meteorological conditions on PM 2.5 and PM 2.5-10 concentrations during the monsoon season in Hanoi, Vietnam

    NASA Astrophysics Data System (ADS)

    Hien, P. D.; Bac, V. T.; Tham, H. C.; Nhan, D. D.; Vinh, L. D.

    Twenty-four hour samples of air particulate matter with aerodynamic diameters from 2 to 10 μm (PM 10) and <2.5 μm (PM 2.5) were collected in Hanoi throughout 1 year since August 1998. The air sampler was located in a meteorological garden where routine surface observations and upper air radiosoundings were conducted. Very high PM 2.5 and PM 2.5-10 concentrations were observed in conjunction with the occurrence of nocturnal radiation inversions from October to December and subsidence temperature inversions (STI) from January to March. In the first case, the PM 2.5-10 fraction was much enhanced and particulate pollution was significantly higher at night than in daytime. During the occurence of STIs particulate mass was almost evenly distributed among the two fractions and no significant diurnal variations in concentrations were observed. In summer (May-September) particulate pollution was much lower than in winter. The multiple regression of 24-h particulate concentrations against meteorological parameters for both the winter and summer monsoon periods shows that the most important determinants of PM 2.5 are wind speed and air temperature, while rainfall and relative humidity largely control the daily variations of PM 2.5-10, indicating the high abundance of soil dust in this fraction. As to turbulence parameters, among the determinants of 24-h particulate concentrations are the vertical gradients of potential temperature and wind speed recorded at 06.30 and 18.30, respectively. Meteorological parameters could explain from 60% to 74% of the day-to-day variations of particulate concentrations.

  11. An engineering model 30 cm ion thruster

    NASA Technical Reports Server (NTRS)

    Poeschel, R. L.; King, H. J.; Schnelker, D. E.

    1973-01-01

    Thruster development at Hughes Research Laboratories and NASA Lewis Research Center has brought the 30-cm mercury bombardment ion thruster to the state of an engineering model. This thruster has been designed to have sufficient internal strength for direct mounting on gimbals, to weigh 7.3 kg, to operate with a corrected overall efficiency of 71%, and to have 10,000 hours lifetime. Subassemblies, such as the ion optical system, isolators, etc., have been upgraded to meet launch qualification standards. This paper presents a summary of the design specifications and performance characteristics which define the interface between the thruster module and the remainder of the propulsion system.

  12. Localization of soil depth for N uptake by Kobresia roots in Tibetan grassland

    NASA Astrophysics Data System (ADS)

    Marten Schleuß, Per-; Steingräber, Laura; Guggenberger, Georg; Kuzyakov, Yakov

    2013-04-01

    The Tibetan Plateau provides the world's largest alpine ecosystem and is dominated by Kobresia grasslands, which cover ca. 450,000 km2. Kobresia pastures are expected to be grazing-induced and are accompanied by sedge-turf varying in thickness between 5 - 30 cm. These pastoral root mat ecosystems are of global and regional importance due to its impact on global water, heat and carbon cycles, its high storage of carbon, nitrogen and other nutrients and its provision of important grazing areas, because they protect against mechanical degradation and provide a fast regrowth after heavy grazing events. Yet, less is known about the development and functioning of this Kobresia root mats. We investigated the nitrogen uptake from different soil depths mainly consisting on Kobresia root mats and N mobilisation into the soil-plant-system by localized 15N additions. A 15N pulse labeling experiment was set up in July 2012 during the vegetation period on sites of the KEMA research station (Kobresia Ecosystem Monitoring Area) near the city Nagqu. 15N urea was injected into six soil depths: 0-1 cm, 1-5 cm, 5-10 cm, 10-15 cm, 15-20 cm, 20-25 cm. Samples of soil, root and shoots were taken 45 days after the 15N labeling. Detailed description of soil profiles were carried out considering basic characteristics of single horizons. Due to low atmospheric N depositions and high N immobilization in the root mats, the study site is limited by plant available N. Hence, N uptake efficiency is assumed to be generally high and thus highest 15N amounts should be recovered in above- and belowground plant biomass. Moreover, by linking information of localization of N uptake and the morphological description of Kobresia-turf profiles, the functional purpose of single horizons can be obtained, which help to understand its successful establishment, functions and future trends with regard to change of climate and management.

  13. Redundant Array Configurations for 21 cm Cosmology

    NASA Astrophysics Data System (ADS)

    Dillon, Joshua S.; Parsons, Aaron R.

    2016-08-01

    Realizing the potential of 21 cm tomography to statistically probe the intergalactic medium before and during the Epoch of Reionization requires large telescopes and precise control of systematics. Next-generation telescopes are now being designed and built to meet these challenges, drawing lessons from first-generation experiments that showed the benefits of densely packed, highly redundant arrays—in which the same mode on the sky is sampled by many antenna pairs—for achieving high sensitivity, precise calibration, and robust foreground mitigation. In this work, we focus on the Hydrogen Epoch of Reionization Array (HERA) as an interferometer with a dense, redundant core designed following these lessons to be optimized for 21 cm cosmology. We show how modestly supplementing or modifying a compact design like HERA’s can still deliver high sensitivity while enhancing strategies for calibration and foreground mitigation. In particular, we compare the imaging capability of several array configurations, both instantaneously (to address instrumental and ionospheric effects) and with rotation synthesis (for foreground removal). We also examine the effects that configuration has on calibratability using instantaneous redundancy. We find that improved imaging with sub-aperture sampling via “off-grid” antennas and increased angular resolution via far-flung “outrigger” antennas is possible with a redundantly calibratable array configuration.

  14. Combining galaxy and 21-cm surveys

    NASA Astrophysics Data System (ADS)

    Cohn, J. D.; White, Martin; Chang, Tzu-Ching; Holder, Gil; Padmanabhan, Nikhil; Doré, Olivier

    2016-04-01

    Acoustic waves travelling through the early Universe imprint a characteristic scale in the clustering of galaxies, QSOs and intergalactic gas. This scale can be used as a standard ruler to map the expansion history of the Universe, a technique known as baryon acoustic oscillations (BAO). BAO offer a high-precision, low-systematics means of constraining our cosmological model. The statistical power of BAO measurements can be improved if the `smearing' of the acoustic feature by non-linear structure formation is undone in a process known as reconstruction. In this paper, we use low-order Lagrangian perturbation theory to study the ability of 21-cm experiments to perform reconstruction and how augmenting these surveys with galaxy redshift surveys at relatively low number densities can improve performance. We find that the critical number density which must be achieved in order to benefit 21-cm surveys is set by the linear theory power spectrum near its peak, and corresponds to densities achievable by upcoming surveys of emission line galaxies such as eBOSS and DESI. As part of this work, we analyse reconstruction within the framework of Lagrangian perturbation theory with local Lagrangian bias, redshift-space distortions, {k}-dependent noise and anisotropic filtering schemes.

  15. Fuel elements of research reactor CM

    SciTech Connect

    Kozlov, A.V.; Morozov, A.V.; Vatulin, A.V.; Ershov, S.A.

    2013-07-01

    In 1961 the CM research reactor was commissioned at the Research Institute of Atomic Reactors (Dimitrovgrad, Russia), it was intended to carry on investigations and the production of transuranium nuclides. The reactor is of a tank type. Original fuel assembly contained plate fuels that were spaced with vanes and corrugated bands. Nickel was used as a cladding material, fuel meat was produced from UO{sub 2} + electrolytic nickel composition. Fuel plates have been replaced by self-spacing cross-shaped dispersion fuels clad in stainless steel. In 2005 the reactor was updated. The purpose of this updating was to increase the quantity of irradiation channels in the reactor core and to improve the neutron balance. The updating was implemented at the expense of 20 % reduction in the quantity of fuel elements in the core which released a space for extra channels and decreased the mass of structural materials in the core. The updated reactor is loaded with modified standard fuel elements with 20 % higher uranium masses. At the same time stainless steel in fuel assembly shrouds was substituted by zirconium alloy. Today in progress are investigations and work to promote the second stage of reactor updating that involve developments of cross-shaped fuel elements having low neutron absorption matrix materials. This article gives an historical account of the design and main technical changes that occurred for the CM reactor since its commissioning.

  16. Aliphatic amines in Antarctic CR2, CM2, and CM1/2 carbonaceous chondrites

    NASA Astrophysics Data System (ADS)

    Aponte, José C.; McLain, Hannah L.; Dworkin, Jason P.; Elsila, Jamie E.

    2016-09-01

    Meteoritic water-soluble organic compounds provide a unique record of the processes that occurred during the formation of the solar system and the chemistry preceding the origins of life on Earth. We have investigated the molecular distribution, compound-specific δ13C isotopic ratios and enantiomeric compositions of aliphatic monoamines present in the hot acid-water extracts of the carbonaceous chondrites LAP 02342 (CR2), GRA 95229 (CR2), LON 94101 (CM2), LEW 90500 (CM2), and ALH 83100 (CM1/2). Analyses of the concentration of monoamines in these meteorites revealed: (a) the CR2 chondrites studied here contain higher concentrations of monoamines relative to the analyzed CM2 chondrites; (b) the concentration of monoamines decreases with increasing carbon number; and (c) isopropylamine is the most abundant monoamine in these CR2 chondrites, while methylamine is the most abundant amine species in these CM2 and CM1/2 chondrites. The δ13C values of monoamines in CR2 chondrite do not correlate with the number of carbon atoms; however, in CM2 and CM1/2 chondrites, the 13C enrichment decreases with increasing monoamine carbon number. The δ13C values of methylamine in CR2 chondrites ranged from -1 to +10‰, while in CM2 and CM1/2 chondrites the δ13C values of methylamine ranged from +41 to +59‰. We also observed racemic compositions of sec-butylamine, 3-methyl-2-butylamine, and sec-pentylamine in the studied carbonaceous chondrites. Additionally, we compared the abundance and δ13C isotopic composition of monoamines to those of their structurally related amino acids. We found that monoamines are less abundant than amino acids in CR2 chondrites, with the opposite being true in CM2 and CM1/2 chondrites. We used these collective data to evaluate different primordial synthetic pathways for monoamines in carbonaceous chondrites and to understand the potential common origins these molecules may share with meteoritic amino acids.

  17. Structural investigation of 5,10-A2B2-type porphyrins: palladium(II) and zinc(II) complexes of 5,10-dibromo-15,20-bis(4-methylphenyl)porphyrin.

    PubMed

    Senge, Mathias O; Zawadzka, Monika

    2014-12-01

    The analysis of [5,10-dibromo-15,20-bis(4-methylphenyl)porphyrinato]palladium(II), [Pd(C34H22Br2N4)], and [5,10-dibromo-15,20-bis(4-methylphenyl)porphyrinato](methanol)zinc(II), [Zn(C34H22Br2N4)(CH4O)], reveals a small but localized influence of the bromine residues on the conformation of the macrocycle. A comparison of the 5,10-dibromo substituent pattern with literature data for 5,15-dibromoporphyrins shows similar in-plane distortions in both but a different mix of out-of-plane distortion modes for the different regiochemical arrangements.

  18. Overcoming the Challenges of 21cm Cosmology

    NASA Astrophysics Data System (ADS)

    Pober, Jonathan

    The highly-redshifted 21cm line of neutral hydrogen is one of the most promising and unique probes of cosmology for the next decade and beyond. The past few years have seen a number of dedicated experiments targeting the 21cm signal from the Epoch of Reionization (EoR) begin operation, including the LOw-Frequency ARray (LOFAR), the Murchison Widefield Array (MWA), and the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER). For these experiments to yield cosmological results, they require new calibration and analysis algorithms which will need to achieve unprecedented levels of separation between the 21cm signal and contaminating foreground emission. Although much work has been spent developing these algorithms over the past decade, their success or failure will ultimately depend on their ability to overcome the complications associated with real-world systems and their inherent complications. The work in this dissertation is closely tied to the late-stage commissioning and early observations with PAPER. The first two chapters focus on developing calibration algorithms to overcome unique problems arising in the PAPER system. To test these algorithms, I rely on not only simulations, but on commissioning observations, ultimately tying the success of the algorithm to its performance on actual, celestial data. The first algorithm works to correct gain-drifts in the PAPER system caused by the heating and cooling of various components (the amplifiers and above ground co-axial cables, in particular). It is shown that a simple measurement of the ambient temperature can remove ˜ 10% gain fluctuations in the observed brightness of calibrator sources. This result is highly encouraging for the ability of PAPER to remove a potentially dominant systematic in its power spectrum and cataloging measurements without resorting to a complicated system overhaul. The second new algorithm developed in this dissertation solves a major calibration challenge not

  19. Comparison of artificial intelligence techniques for prediction of soil temperatures in Turkey

    NASA Astrophysics Data System (ADS)

    Citakoglu, Hatice

    2016-08-01

    Soil temperature is a meteorological data directly affecting the formation and development of plants of all kinds. Soil temperatures are usually estimated with various models including the artificial neural networks (ANNs), adaptive neuro-fuzzy inference system (ANFIS), and multiple linear regression (MLR) models. Soil temperatures along with other climate data are recorded by the Turkish State Meteorological Service (MGM) at specific locations all over Turkey. Soil temperatures are commonly measured at 5-, 10-, 20-, 50-, and 100-cm depths below the soil surface. In this study, the soil temperature data in monthly units measured at 261 stations in Turkey having records of at least 20 years were used to develop relevant models. Different input combinations were tested in the ANN and ANFIS models to estimate soil temperatures, and the best combination of significant explanatory variables turns out to be monthly minimum and maximum air temperatures, calendar month number, depth of soil, and monthly precipitation. Next, three standard error terms (mean absolute error (MAE, °C), root mean squared error (RMSE, °C), and determination coefficient (R 2 )) were employed to check the reliability of the test data results obtained through the ANN, ANFIS, and MLR models. ANFIS (RMSE 1.99; MAE 1.09; R 2 0.98) is found to outperform both ANN and MLR (RMSE 5.80, 8.89; MAE 1.89, 2.36; R 2 0.93, 0.91) in estimating soil temperature in Turkey.

  20. 70-cm radar observations of 433 Eros

    NASA Technical Reports Server (NTRS)

    Campbell, D. B.; Pettengill, G. H.; Shapiro, I. I.

    1976-01-01

    Radar observations of 433 Eros were made at the Arecibo Observatory using a wavelength of 70 cm during the close approach of Eros to earth in mid-January, 1975. A peak radar cross section of plus or minus 15 sq km was observed. The spectral broadening obtained was approximately 30 Hz, which is consistent with a value of 16 km for the maximum radius of the asteroid. The surface of Eros appears to be relatively rough at the scale of a wavelength as compared to the surfaces of the terrestrial planets and the moon. The composition of the surface is not well determined, except that it cannot be a highly conducting metal. A single measurement each of round-trip echo times delay and Doppler shift was made.

  1. NASA 30 Cm Ion Thruster Development Status

    NASA Technical Reports Server (NTRS)

    Patterson, Michael J.; Haag, Thomas W.; Rawlin, Vincent K.; Kussmaul, Michael T.

    1995-01-01

    A 30 cm diameter xenon ion thruster is under development at NASA to provide an ion propulsion option for missions of national interest and it is an element of the NASA Solar Electric Propulsion Technology Applications Readiness (NSTAR) program established to validate ion propulsion for space flight applications. The thruster has been developed to an engineering model level and it incorporates innovations in design, materials, and fabrication techniques compared to those employed to conventional ion thrusters. The performance of both functional and engineering model thrusters has been assessed including thrust stand measurements, over an input power range of 0.5-2.3 kW. Attributes of the engineering model thruster include an overall mass of 6.4 kg, and an efficiency of 65 percent and thrust of 93 mN at 2.3 kW input power. This paper discusses the design, performance, and lifetime expectations of the functional and engineering model thrusters under development at NASA.

  2. 21 Cm Tomography With the Alfalfa Survey

    NASA Astrophysics Data System (ADS)

    Fry, Alexander B.; Boutan, C.; Carroll, P. A.; Hazelton, B.; Morales, M. F.

    2011-01-01

    Neutral hydrogen (HI) 21cm intensity mapping, or HI tomography is a promising technique being utilized by several upcoming experiments (LOFAR, MWA, SKA). The measurement of volume averaged neutral hydrogen mass density in synoptic sky surveys can be applied to the study of the HI mass function, the distribution of large scale structure, the reionization of the universe, and the expansion history of the universe through such standard rulers as baryonic acoustic oscillations. In order to prepare for future experiments, in particular the Murchison Widefield Array (MWA), we analyze the Arecbo Legacy Fast ALFA (Arecibo L-Band Feed Array) Feed Array (ALFALFA) survey data to probe the spatial density variations of HI in our local universe (z <0.06) where data is currently available. We address challenges unique to data of this kind, such as identifying and subtracting out signal from RFI and local galactic sources, and characterizing the ALFA array beam pattern which dictates sensitivity and resolution.

  3. The 30-cm ion thruster power processor

    NASA Technical Reports Server (NTRS)

    Herron, B. G.; Hopper, D. J.

    1978-01-01

    A power processor unit for powering and controlling the 30 cm Mercury Electron-Bombardment Ion Thruster was designed, fabricated, and tested. The unit uses a unique and highly efficient transistor bridge inverter power stage in its implementation. The system operated from a 200 to 400 V dc input power bus, provides 12 independently controllable and closely regulated dc power outputs, and has an overall power conditioning capacity of 3.5 kW. Protective circuitry was incorporated as an integral part of the design to assure failure-free operation during transient and steady-state load faults. The implemented unit demonstrated an electrical efficiency between 91.5 and 91.9 at its nominal rated load over the 200 to 400 V dc input bus range.

  4. Long-term effect of agricultural reclamation on soil chemical properties of a coastal saline marsh in Bohai Rim, northern China.

    PubMed

    Wang, Yidong; Wang, Zhong-Liang; Feng, Xiaoping; Guo, Changcheng; Chen, Qing

    2014-01-01

    Over the past six decades, coastal wetlands in China have experienced rapid and extensive agricultural reclamation. In the context of saline conditions, long-term effect of cultivation after reclamation on soil chemical properties has not been well understood. We studied this issue using a case of approximately 60-years cultivation of a coastal saline marsh in Bohai Rim, northern China. The results showed that long-term reclamation significantly decreased soil organic carbon (SOC) (-42.2%) and total nitrogen (TN) (-25.8%) at surface layer (0-30 cm) as well as their stratification ratios (SRs) (0-5 cm:50-70 cm and 5-10 cm:50-70 cm). However, there was no significant change in total phosphorus (TP) as well as its SRs under cultivation. Cultivation markedly reduced ratios of SOC to TN, SOC to TP and TN to TP at surface layer (0-30 cm) and their SRs (0-5 cm:50-70 cm). After cultivation, electrical conductivity and salinity significantly decreased by 60.1% and 55.3% at 0-100 cm layer, respectively, suggesting a great desalinization. In contrast, soil pH at 20-70 cm horizons notably increased as an effect of reclamation. Cultivation also changed compositions of cations at 0-10 cm layer and anions at 5-100 cm layer, mainly decreasing the proportion of Na+, Cl- and SO4(2-). Furthermore, cultivation significantly reduced the sodium adsorption ratio and exchangeable sodium percentage in plow-layer (0-20 cm) but not residual sodium carbonate, suggesting a reduction in sodium harm.

  5. Long-term effect of agricultural reclamation on soil chemical properties of a coastal saline marsh in Bohai Rim, northern China.

    PubMed

    Wang, Yidong; Wang, Zhong-Liang; Feng, Xiaoping; Guo, Changcheng; Chen, Qing

    2014-01-01

    Over the past six decades, coastal wetlands in China have experienced rapid and extensive agricultural reclamation. In the context of saline conditions, long-term effect of cultivation after reclamation on soil chemical properties has not been well understood. We studied this issue using a case of approximately 60-years cultivation of a coastal saline marsh in Bohai Rim, northern China. The results showed that long-term reclamation significantly decreased soil organic carbon (SOC) (-42.2%) and total nitrogen (TN) (-25.8%) at surface layer (0-30 cm) as well as their stratification ratios (SRs) (0-5 cm:50-70 cm and 5-10 cm:50-70 cm). However, there was no significant change in total phosphorus (TP) as well as its SRs under cultivation. Cultivation markedly reduced ratios of SOC to TN, SOC to TP and TN to TP at surface layer (0-30 cm) and their SRs (0-5 cm:50-70 cm). After cultivation, electrical conductivity and salinity significantly decreased by 60.1% and 55.3% at 0-100 cm layer, respectively, suggesting a great desalinization. In contrast, soil pH at 20-70 cm horizons notably increased as an effect of reclamation. Cultivation also changed compositions of cations at 0-10 cm layer and anions at 5-100 cm layer, mainly decreasing the proportion of Na+, Cl- and SO4(2-). Furthermore, cultivation significantly reduced the sodium adsorption ratio and exchangeable sodium percentage in plow-layer (0-20 cm) but not residual sodium carbonate, suggesting a reduction in sodium harm. PMID:24695526

  6. Effects of nitrogen and phosphorus fertilization on soil carbon fractions in alpine meadows on the Qinghai-Tibetan Plateau.

    PubMed

    Li, Jin Hua; Yang, Yu Jie; Li, Bo Wen; Li, Wen Jin; Wang, Gang; Knops, Johannes M H

    2014-01-01

    In grassland ecosystems, N and P fertilization often increase plant productivity, but there is no concensus if fertilization affects soil C fractions. We tested effects of N, P and N+P fertilization at 5, 10, 15 g m-2 yr-1 (N5, N10, N15, P5, P10, P15, N5P5, N10P10, and N15P15) compared to unfertilized control on soil C, soil microbial biomass and functional diversity at the 0-20 cm and 20-40 cm depth in an alpine meadow after 5 years of continuous fertilization. Fertilization increased total aboveground biomass of community and grass but decreased legume and forb biomass compared to no fertilization. All fertilization treatments decreased the C:N ratios of legumes and roots compared to control, however fertilization at rates of 5 and 15 g m-2 yr-1 decreased the C:N ratios of the grasses. Compared to the control, soil microbial biomass C increased in N5, N10, P5, and P10 in 0-20 cm, and increased in N10 and P5 while decreased in other treatments in 20-40 cm. Most of the fertilization treatments decreased the respiratory quotient (qCO2) in 0-20 cm but increased qCO2 in 20-40 cm. Fertilization increased soil microbial functional diversity (except N15) but decreased cumulative C mineralization (except in N15 in 0-20 cm and N5 in 20-40 cm). Soil organic C (SOC) decreased in P5 and P15 in 0-20 cm and for most of the fertilization treatments (except N15P15) in 20-40 cm. Overall, these results suggested that soils will not be a C sink (except N15P15). Nitrogen and phosphorus fertilization may lower the SOC pool by altering the plant biomass composition, especially the C:N ratios of different plant functional groups, and modifying C substrate utilization patterns of soil microbial communities. The N+P fertilization at 15 g m-2 yr-1 may be used in increasing plant aboveground biomass and soil C accumulation under these meadows.

  7. Evaluation of Argonne 9-cm and 10-cm Annular Centrifugal Contactors for SHINE Solution Processing

    SciTech Connect

    Wardle, Kent E.; Pereira, Candido; Vandegrift, George

    2015-02-01

    Work is in progress to evaluate the SHINE Medical Technologies process for producing Mo-99 for medical use from the fission of dissolved low-enriched uranium (LEU). This report addresses the use of Argonne annular centrifugal contactors for periodic treatment of the process solution. In a letter report from FY 2013, Pereira and Vandegrift compared the throughput and physical footprint for the two contactor options available from CINC Industries: the V-02 and V-05, which have rotor diameters of 5 cm and 12.7 cm, respectively. They suggested that an intermediately sized “Goldilocks” contactor might provide a better balance between throughput and footprint to meet the processing needs for the uranium extraction (UREX) processing of the SHINE solution to remove undesired fission products. Included with the submission of this letter report are the assembly drawings for two Argonne-design contactors that are in this intermediate range—9-cm and 10-cm rotors, respectively. The 9-cm contactor (drawing number CE-D6973A, stamped February 15, 1978) was designed as a single-stage unit and built and tested in the late 1970s along with other size units, both smaller and larger. In subsequent years, a significant effort to developed annular centrifugal contactors was undertaken to support work at Hanford implementing the transuranic extraction (TRUEX) process. These contactors had a 10-cm rotor diameter and were fully designed as multistage units with four stages per assembly (drawing number CMT-E1104, stamped March 14, 1990). From a technology readiness perspective, these 10-cm units are much farther ahead in the design progression and, therefore, would require significantly less re-working to make them ready for UREX deployment. Additionally, the overall maximum throughput of ~12 L/min is similar to that of the 9-cm unit (10 L/min), and the former could be efficiently operated over much of the same range of throughput. As a result, only the 10-cm units are considered here

  8. Effects of cadmium amendments on low-molecular-weight organic acid exudates in rhizosphere soils of tobacco and sunflower.

    PubMed

    Chiang, Po-Neng; Wang, Ming Kuang; Chiu, Chih Yu; Chou, Shu-Yen

    2006-10-01

    To recognize physiological response of plants to cadmium (Cd) toxicity in rhizosphere of plants, the pot experiments were employed to investigate how low-molecular-weight organic acids (LMWOAs) were exudated from tobacco and sunflower roots of Cd-amended soils. The aims of this study were to assess the effect of LMWOAs on uptake of Cd by tobacco and sunflower under pot experiments, thus comparing the ability of tobacco and sunflower for phytoremediation. Surface soils (0-20 cm) were collected from Taichung Experiment Station (TC) (silty loam). Cadmium chloride (CdCl(2)) was amended into TC soil, giving Cd concentrations of 1, 5, 10 mg kg(-1) soil. Soils with different concentrations of Cd were put into 12 cm (i.d.) pots for incubation, and then 2-week-old tobacco and sunflower seedlings were transplanted into the pots. Tobacco and sunflower were grown in greenhouse for 50 days, respectively. The rhizosphere and bulk soils, and fresh plant tissues were collected after harvest. The Cd concentrations in the plant and transfer factor values in the sunflower were higher than that in the tobacco. No LMWOAs were detected by gas chromatograph in bulk soils, and low amounts of LMWOAs were found in uncontaminated rhizosphere soils. Acetic, lactic, glycolic, malic, maleic, and succinic acids were found in the tobacco and sunflower rhizosphere soils. Concentrations of LMWOAs increased with increasing amendment of Cd concentrations in tobacco and sunflower rhizosphere soils. Correlation coefficient (r) of concentrations of Cd amendment versus LMWOAs exudates of tobacco and sunflower were 0.85 and 0.98, respectively. These results suggest that the different levels of LMWOAs present in the rhizosphere soil play an important role in the solubilization of Cd that bound with soil particle into soil solution and then uptake by plants.

  9. Evaluation of bottom ash and composted manure blends as a soil amendment material.

    PubMed

    Mukhtar, S; Kenimer, A L; Sadaka, S S; Mathis, J G

    2003-09-01

    The long-term goal of this project was to find alternative uses for bottom ash (BA) and composted dairy manure (CM), by-products of coal combustion and livestock production, respectively. The study discussed in this paper focused on potential water quality impacts associated with using blended BA and CM as a soil amendment. The constituents of BA and CM include heavy metals and other chemicals that, while essential nutrients for plant growth, also pose a potential threat to water quality. Four blends (BA:CM, v/v) namely, B1 (100%:0%), B2 (70%:30%), B3 (50%:50%) and B4 (0%:100%), were subjected to flow-through water table management and two blends, B2 (70%:30%) and B3 (50%:50%), were subjected to constant head water table management using de-ionized water. Leachate and standing water from saturated and flooded blends of BA and CM were examined for total solids (TS), volatile solids (VS), COD, pH, total Kjeldahl nitrogen (TKN), NO(3)-N, total P, total K as well as selected metals over a 5 and 7 week period for flow-through and constant head watertables, respectively. The results showed that higher CM content resulted in higher TS, VS, TKN, P and K concentrations in the leachate and standing water. Concentrations of these constituents were higher in leachate than in the standing water. Even though, marked reductions of most chemicals in the leachate and standing water were realized within one to three weeks, initially high concentrations of chemicals in leachate and standing water from these particular blends made them unsuitable as soil amendment material. Based upon these results, it was concluded that additional column studies of BA and CM blends with reduced CM content (5%, 10% and 20%) should be performed to further assess the feasibility of BA and CM blends as an environmentally safe soil amendment material.

  10. Evaluation of bottom ash and composted manure blends as a soil amendment material.

    PubMed

    Mukhtar, S; Kenimer, A L; Sadaka, S S; Mathis, J G

    2003-09-01

    The long-term goal of this project was to find alternative uses for bottom ash (BA) and composted dairy manure (CM), by-products of coal combustion and livestock production, respectively. The study discussed in this paper focused on potential water quality impacts associated with using blended BA and CM as a soil amendment. The constituents of BA and CM include heavy metals and other chemicals that, while essential nutrients for plant growth, also pose a potential threat to water quality. Four blends (BA:CM, v/v) namely, B1 (100%:0%), B2 (70%:30%), B3 (50%:50%) and B4 (0%:100%), were subjected to flow-through water table management and two blends, B2 (70%:30%) and B3 (50%:50%), were subjected to constant head water table management using de-ionized water. Leachate and standing water from saturated and flooded blends of BA and CM were examined for total solids (TS), volatile solids (VS), COD, pH, total Kjeldahl nitrogen (TKN), NO(3)-N, total P, total K as well as selected metals over a 5 and 7 week period for flow-through and constant head watertables, respectively. The results showed that higher CM content resulted in higher TS, VS, TKN, P and K concentrations in the leachate and standing water. Concentrations of these constituents were higher in leachate than in the standing water. Even though, marked reductions of most chemicals in the leachate and standing water were realized within one to three weeks, initially high concentrations of chemicals in leachate and standing water from these particular blends made them unsuitable as soil amendment material. Based upon these results, it was concluded that additional column studies of BA and CM blends with reduced CM content (5%, 10% and 20%) should be performed to further assess the feasibility of BA and CM blends as an environmentally safe soil amendment material. PMID:12798111

  11. ICD-9-CM to ICD-10-CM Codes: What? Why? How?

    PubMed Central

    Cartwright, Donna J.

    2013-01-01

    The wound care industry will gain many benefits when International Classification of Diseases (ICD)-10-Clinical Modification (CM) is implemented. One of the main benefits is that the disease classifications will be consistent with current clinical practice and medical technology advances. The new classification codes will be very granular, which means the level of specificity will greatly improve. Numerous new codes will represent more specific anatomic sites, etiologies, comorbidities, and complications, and will improve the ability to demonstrate severity of illness. For instance, the new feature of laterality is directly built into the new codes: separate codes will distinguish right, left, and bilateral, where needed. The increased granularity will provide better analysis of disease patterns and outbreak of disease. Additionally, the United States will finally be using the same diagnosis coding system as the rest of the world. This article will describe what the ICD-9-CM/ICD-10-CM codes are, why they are so important, and how clinicians and researchers will convert from ICD-9-CM to ICD-10-CM effective October 1, 2014. PMID:24761333

  12. The 15 cm diameter ion thruster research

    NASA Technical Reports Server (NTRS)

    Wilbur, P. J.

    1974-01-01

    The startup reliability of a 15 cm diameter mercury bombardment ion thruster which employs a pulsed high voltage tickler electrode on the main and neutralizer cathodes is examined. Startup of the thruster is achieved 100% of the time on the main cathode and 98.7% of the time on the neutralizer cathode over a 3640 cycle test. The thruster was started from a 20 C initial condition and operated for an hour at a 600 mA beam current. An energy efficiency of 75% and a propellant utilization efficiency of 77% was achieved over the complete cycle. The effect of a single cusp magnetic field thruster length on its performance is discussed. Guidelines are formulated for the shaping of magnetic field lines in thrusters. A model describing double ion production in mercury discharges is presented. The production route is shown to occur through the single ionic ground state. Photographs of the interior of an operating-hollow cathode are presented. A cathode spot is shown to be present if the cathode is free of low work-function surfaces. The spot is observed if a low work-function oxide coating is applied to the cathode insert. Results show that low work-function oxide coatings tend to migrate during thruster operation.

  13. Engineering model 8-cm thruster subsystem

    NASA Technical Reports Server (NTRS)

    Herron, B. G.; Hyman, J.; Hopper, D. J.; Williamson, W. S.; Dulgeroff, C. R.; Collett, C. R.

    1978-01-01

    An Engineering Model (EM) 8 cm Ion Thruster Propulsion Subsystem was developed for operation at a thrust level 5 mN (1.1 mlb) at a specific impulse 1 sub sp = 2667 sec with a total system input power P sub in = 165 W. The system dry mass is 15 kg with a mercury-propellant-reservoir capacity of 8.75 kg permitting uninterrupted operation for about 12,500 hr. The subsystem can be started from a dormant condition in a time less than or equal to 15 min. The thruster has a design lifetime of 20,000 hr with 10,000 startup cycles. A gimbal unit is included to provide a thrust vector deflection capability of + or - 10 degrees in any direction from the zero position. The EM subsystem development program included thruster optimization, power-supply circuit optimization and flight packaging, subsystem integration, and subsystem acceptance testing including a cyclic test of the total propulsion package.

  14. Source identification and apportionment of PM2.5 and PM2.5-10 in iron and steel scrap smelting factory environment using PMF, PCFA and UNMIX receptor models.

    PubMed

    Ogundele, Lasun T; Owoade, Oyediran K; Olise, Felix S; Hopke, Philip K

    2016-10-01

    To identify the potential sources responsible for the particulate matter emission from secondary iron and steel smelting factory environment, PM2.5 and PM2.5-10 particles were collected using the low-volume air samplers twice a week for a year. The samples were analyzed for the elemental and black carbon content using x-ray fluorescence spectrometer and optical transmissometer, respectively. The average mass concentrations were 216.26, 151.68, and 138. 62 μg/m(3) for PM2.5 and 331.36, 190.01, and 184.60 μg/m(3) for PM2.5-10 for the production, outside M1 and outside M2 sites, respectively. The same size resolved data set were used as input for the positive matrix factorization (PMF), principal component factor analysis (PCFA), and Unmix (UNMIX) receptor modeling in order to identify the possible sources of particulate matter and their contribution. The PMF resolved four sources with their respective contributions were metal processing (33 %), e-waste (33 %), diesel emission (22 %) and soil (12 %) for PM2.5, and coking (50 %), soil (29 %), metal processing (16 %) and diesel combustion (5 %) for PM2.5-10. PCFA identified soil, metal processing, Pb source, and diesel combustion contributing 45, 41, 9, and 5 %, respectively to PM2.5 while metal processing, soil, coal combustion and open burning contributed 43, 38, 12, and 7 %, respectively to the PM2.5-10. Also, UNMIX identified metal processing, soil, and diesel emission with 43, 42 and 15 % contributions, respectively for the fine fraction, and metal processing (71 %), soil (21 %) and unidentified source (1 %) for the coarse fraction. The study concluded that metal processing and e-waste are the major sources contributing to the fine fraction while coking and soil contributed to the coarse fraction within the factory environment. The application of PMF, PCFA and UNMIX receptor models improved the source identification and apportionment of particulate matter drive in the study area. PMID:27645143

  15. Source identification and apportionment of PM2.5 and PM2.5-10 in iron and steel scrap smelting factory environment using PMF, PCFA and UNMIX receptor models.

    PubMed

    Ogundele, Lasun T; Owoade, Oyediran K; Olise, Felix S; Hopke, Philip K

    2016-10-01

    To identify the potential sources responsible for the particulate matter emission from secondary iron and steel smelting factory environment, PM2.5 and PM2.5-10 particles were collected using the low-volume air samplers twice a week for a year. The samples were analyzed for the elemental and black carbon content using x-ray fluorescence spectrometer and optical transmissometer, respectively. The average mass concentrations were 216.26, 151.68, and 138. 62 μg/m(3) for PM2.5 and 331.36, 190.01, and 184.60 μg/m(3) for PM2.5-10 for the production, outside M1 and outside M2 sites, respectively. The same size resolved data set were used as input for the positive matrix factorization (PMF), principal component factor analysis (PCFA), and Unmix (UNMIX) receptor modeling in order to identify the possible sources of particulate matter and their contribution. The PMF resolved four sources with their respective contributions were metal processing (33 %), e-waste (33 %), diesel emission (22 %) and soil (12 %) for PM2.5, and coking (50 %), soil (29 %), metal processing (16 %) and diesel combustion (5 %) for PM2.5-10. PCFA identified soil, metal processing, Pb source, and diesel combustion contributing 45, 41, 9, and 5 %, respectively to PM2.5 while metal processing, soil, coal combustion and open burning contributed 43, 38, 12, and 7 %, respectively to the PM2.5-10. Also, UNMIX identified metal processing, soil, and diesel emission with 43, 42 and 15 % contributions, respectively for the fine fraction, and metal processing (71 %), soil (21 %) and unidentified source (1 %) for the coarse fraction. The study concluded that metal processing and e-waste are the major sources contributing to the fine fraction while coking and soil contributed to the coarse fraction within the factory environment. The application of PMF, PCFA and UNMIX receptor models improved the source identification and apportionment of particulate matter drive in the study area.

  16. [Soil microbial functional diversity of different altitude Pinus koraiensis forests].

    PubMed

    Han, Dong-xue; Wang, Ning; Wang, Nan-nan; Sun, Xue; Feng, Fu-juan

    2015-12-01

    In order to comprehensively understand the soil microbial carbon utilization characteristics of Pinus koraiensis forests, we took the topsoil (0-5 cm and 5-10 cm) along the 700-1100 m altitude in Changbai Mountains and analyzed the vertical distributed characteristics and variation of microbial functional diversity along the elevation gradient by Biolog microplate method. The results showed that there were significant differences in functional diversity of microbial communities at different elevations. AWCD increased with the extension of incubation time and AWCD at the same soil depth gradually decreased along with increasing altitude; Shannon, Simpson and McIntosh diversity index also showed the same trend with AWCD and three different diversity indices were significantly different along the elevation gradient; Species diversity and functional diversity showed the same variation. The utilization intensities of six categories carbon sources had differences while amino acids were constantly the most dominant carbon source. Principal component analysis (PCA) identified that soil microbial carbon utilization at different altitudes had obvious spatial differentiation, as reflected in the use of carbohydrates, amino acids and carboxylic acids. In addition, the cluster of the microbial diversity indexes and AWCD values of different altitudes showed that the composition of vegetation had a significant impact on soil microbial composition and functional activity. PMID:27112001

  17. [Soil microbial functional diversity of different altitude Pinus koraiensis forests].

    PubMed

    Han, Dong-xue; Wang, Ning; Wang, Nan-nan; Sun, Xue; Feng, Fu-juan

    2015-12-01

    In order to comprehensively understand the soil microbial carbon utilization characteristics of Pinus koraiensis forests, we took the topsoil (0-5 cm and 5-10 cm) along the 700-1100 m altitude in Changbai Mountains and analyzed the vertical distributed characteristics and variation of microbial functional diversity along the elevation gradient by Biolog microplate method. The results showed that there were significant differences in functional diversity of microbial communities at different elevations. AWCD increased with the extension of incubation time and AWCD at the same soil depth gradually decreased along with increasing altitude; Shannon, Simpson and McIntosh diversity index also showed the same trend with AWCD and three different diversity indices were significantly different along the elevation gradient; Species diversity and functional diversity showed the same variation. The utilization intensities of six categories carbon sources had differences while amino acids were constantly the most dominant carbon source. Principal component analysis (PCA) identified that soil microbial carbon utilization at different altitudes had obvious spatial differentiation, as reflected in the use of carbohydrates, amino acids and carboxylic acids. In addition, the cluster of the microbial diversity indexes and AWCD values of different altitudes showed that the composition of vegetation had a significant impact on soil microbial composition and functional activity.

  18. [Effects of urease and nitrification inhibitors on alleviating the oxidation and leaching of soil urea's hydrolyzed product ammonium].

    PubMed

    Chen, Zhenhua; Chen, Lijun; Wu, Zhijie

    2005-02-01

    With simulation test of in-situ soil column, this paper studied the effects of urease inhibitor hydroquinone (HQ), nitrification inhibitors coated calcium carbide (ECC) and dicyandiamide (DCD),and their different combinations on the persistence, oxidation, and leaching of soil urea's hydrolyzed product ammonium. The results showed that compared with other treatments, the combination of HQ and DCD could effectively inhibit the oxidation of the ammonium, and make it as exchangeable form reserve in soil in a larger amount and a longer period. The inhibition of this oxidation not only decreased the accumulation of oxidized product NO3- in soil, but also decreased the potential of NO3- leaching, making the NO3- only leach to 5-10 cm in depth, and the leached amount significantly decreased. PMID:15852915

  19. [Effects of urease and nitrification inhibitors on alleviating the oxidation and leaching of soil urea's hydrolyzed product ammonium].

    PubMed

    Chen, Zhenhua; Chen, Lijun; Wu, Zhijie

    2005-02-01

    With simulation test of in-situ soil column, this paper studied the effects of urease inhibitor hydroquinone (HQ), nitrification inhibitors coated calcium carbide (ECC) and dicyandiamide (DCD),and their different combinations on the persistence, oxidation, and leaching of soil urea's hydrolyzed product ammonium. The results showed that compared with other treatments, the combination of HQ and DCD could effectively inhibit the oxidation of the ammonium, and make it as exchangeable form reserve in soil in a larger amount and a longer period. The inhibition of this oxidation not only decreased the accumulation of oxidized product NO3- in soil, but also decreased the potential of NO3- leaching, making the NO3- only leach to 5-10 cm in depth, and the leached amount significantly decreased.

  20. [Reponses of soil total organic carbon and dissolved organic carbon to simulated nitrogen deposition in temperate typical steppe in Inner Mongolia, China].

    PubMed

    Qi, Yu-Chun; Peng, Qin; Dong, Yun-She; Xiao, Sheng-Sheng; Sun, Liang-Jie; Liu, Xin-Chao; He, Ya-Ting; Jia, Jun-Qiang; Cao, Cong-Cong

    2014-08-01

    Based on a field manipulative nitrogen (N) addition experiment, the effects of atmospheric N deposition level change on the contents, inter-annual variation and profile distribution of soil total organic carbon (TOC) and dissolved organic carbon (DOC) were investigated from May, 2008 to October, 2011 in a temperate typical steppe in Inner Mongolia of China, and the relationship between TOC and DOC was also discussed. The treatments in the manipulative experiment included N additions at rates of 0, 5, 10, and 20 g x (m2 x a)(-1), representing the control (CK), low N (LN), medium N (MN), and high N (HN) treatment, respectively. The results indicated that the concentrations of soil TOC and DOC decreased progressively with soil depth in all cases except for the DOC at 10-20 cm depth in individual years. The increase of N input in typical steppe did not change the vertical distribution of soil TOC and DOC, but reduced the vertical variation of TOC and increased the vertical variation of DOC in the surface soil horizon. In addition, the contents of soil TOC and DOC at 0- 10 cm and 10- 20 cm soil layers changed insignificantly after the continuous increase in anthropogenic N input for four years. The soil organic C density of 0-20 cm soil layer for different N treatment levels varied between 3.9 kg x m(-2) and 5.6 kg x m(-2), and the soil organic C densities of fertilized treatments in the first two years were similar to or slightly lower than those of CK, while in the following two years, the increase in N deposition gradually played a positive role in increasing soil organic C density, but the differences in soil TOC and DOC contents between CK and fertilized plots were not significant (P > 0.05). The ratio of soil DOC to TOC (DOC/TOC) varied from 0.32% to 1.09%. The increase in N deposition generally lowered the proportion of DOC in soil TOC, which was conducive to the accumulation of soil organic C. The change of soil DOC was positively correlated with that of TOC (P

  1. Synthesis and anti-tubercular activity of N(2)-arylbenzo[g]isoquinoline-5,10-dione-3-iminium bromides.

    PubMed

    Rotthier, G; Cappoen, D; Nguyen, Quang Trung; Dang Thi, Tuyet Anh; Mathys, V; Nguyen, Van Tuyen; Huygen, K; Maes, L; Cos, P; Abbaspour Tehrani, K

    2016-02-14

    Tuberculosis has remained a challenge for medicinal chemists worldwide. In the framework of a collaborative program to identify and evaluate novel antitubercular candidate compounds, the biological properties of benzo[g]isoquinoline-5,10-diones have been found to be very promising. In this paper we have further expanded the library by incorporation of an amidinium moiety into the benzo[g]isoquinoline-5,10-dione scaffold. The presence of this functional group also increased the solubility of the quinones in polar solvents. To this purpose N(2)-arylbenzo[g]isoquinoline-5,10-dione-3-iminium bromides were synthesized in a straightforward way by means of a reaction of anilines with 2-(bromomethyl)-3-(cyanomethyl)-1,4-dimethoxynaphthalene. Following the biological evaluation, N(2)-(4-chlorophenyl)-5,10-dioxobenzo[g]isoquinoline-3(2H)-iminium bromide (MIC = 1.16 μM, CC50 = 28.51 μM, SI = 24.58) was selected as the most promising representative. Apart from the nano-molar anti-mycobacterial activity, the compound was able to target intracellular residing Mycobacterium tuberculosis and the susceptibility of a multi-drug-resistant strain towards the compound was confirmed.

  2. A sub-cm micromachined electron microscope

    NASA Technical Reports Server (NTRS)

    Feinerman, A. D.; Crewe, D. A.; Perng, D. C.; Shoaf, S. E.; Crewe, A. V.

    1993-01-01

    A new approach for fabricating macroscopic (approximately 10x10x10 mm(exp 3)) structures with micron accuracy has been developed. This approach combines the precision of semiconductor processing and fiber optic technologies. A (100) silicon wafer is anisotropically etched to create four orthogonal v-grooves and an aperture on each 10x12 mm die. Precision 308 micron optical fibers are sandwiched between the die to align the v-grooves. The fiber is then anodically bonded to the die above and below it. This procedure is repeated to create thick structures and a stack of 5 or 6 die will be used to create a miniature scanning electron microscope (MSEM). Two die in the structure will have a segmented electrode to deflect the beam and correct for astigmatism. The entire structure is UHV compatible. The performance of an SEM improves as its length is reduced and a sub-cm 2 keV MSEM with a field emission source should have approximately 1 nm resolution. A low voltage high resolution MSEM would be useful for the examination of biological specimens and semiconductors with a minimum of damage. The first MSEM will be tested with existing 6 micron thermionic sources. In the future a micromachined field emission source will be used. The stacking technology presented in this paper can produce an array of MSEMs 1 to 30 mm in length with a 1 mm or larger period. A key question being addressed by this research is the optimum size for a low voltage MSEM which will be determined by the required spatial resolution, field of view, and working distance.

  3. Source identification and apportionment of heavy metals in urban soil profiles.

    PubMed

    Luo, Xiao-San; Xue, Yan; Wang, Yan-Ling; Cang, Long; Xu, Bo; Ding, Jing

    2015-05-01

    Because heavy metals (HMs) occurring naturally in soils accumulate continuously due to human activities, identifying and apportioning their sources becomes a challenging task for pollution prevention in urban environments. Besides the enrichment factors (EFs) and principal component analysis (PCA) for source classification, the receptor model (Absolute Principal Component Scores-Multiple Linear Regression, APCS-MLR) and Pb isotopic mixing model were also developed to quantify the source contribution for typical HMs (Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn) in urban park soils of Xiamen, a representative megacity in southeast China. Furthermore, distribution patterns of their concentrations and sources in 13 soil profiles (top 20 cm) were investigated by different depths (0-5, 5-10, 10-20 cm). Currently the principal anthropogenic source for HMs in urban soil of China is atmospheric deposition from coal combustion rather than vehicle exhaust. Specifically for Pb source by isotopic model ((206)Pb/(207)Pb and (208)Pb/(207)Pb), the average contributions were natural (49%)>coal combustion (45%)≫traffic emissions (6%). Although the urban surface soils are usually more contaminated owing to recent and current human sources, leaching effects and historic vehicle emissions can also make deep soil layer contaminated by HMs.

  4. Soil respiration in four different land use systems in north central Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Arevalo, Carmela B. M.; Bhatti, Jagtar S.; Chang, Scott X.; Jassal, Rachhpal S.; Sidders, Derek

    2010-03-01

    This study compares soil respiration and its heterotrophic and autotrophic components in four land use types: agriculture, 2 and 9 year old hybrid poplar plantations, grassland, and a native aspen stand in north central Alberta, Canada, over a period of two growing seasons (2006 and 2007). The differences were examined with respect to substrate quality and quantity, fine root biomass, and nutrient availability, in addition to soil temperature and soil water content. Cumulative soil C loss via soil respiration averaged over the two growing seasons was (in decreasing order) 781, 551, 523, 502, and 428 g C m-2 for native aspen stand, 9 year old hybrid poplar plantation, grassland, agriculture and 2 year old hybrid poplar plantation, respectively. We found that ˜75% of soil respiration in the native aspen stand originated from the top 7.5-10 cm litter-fibric-humus layer. Seasonal heterotrophic and autotrophic respiration among the land uses ranged from 97 to 272 and 333 to 560 g C m-2, respectively, contributing up to 35% and 83% of total soil respiration, respectively. The variability in soil respiration across different land uses was explained mainly by site differences in soil temperature (88-94%). Soil respiration followed a pronounced seasonal trend: increasing during the growing season and converging to a minimum in the fall. Soil respiration under different land uses was influenced by (1) ecosystem C stock, (2) temperature sensitivity (Q10) of organic matter present, and (3) organic matter decomposability as indicated by the natural abundance of δ13C. Heterotrophic respiration was influenced by soil temperature, while autotrophic respiration was influenced by fine root biomass and nutrient (NO3- and P) availability. These results are useful in estimating potential responses of soil respiration and its components to future land management and climate change.

  5. Vertical migration of plutonium-239 + -240, americium-241 and caesium-137 fallout in a forest soil under spruce.

    PubMed

    Bunzl, K; Kracke, W; Schimmack, W

    1992-03-01

    The vertical activity distributions of fallout 238Pu, 239+240Pu, 241Am, 134Cs and 137Cs in a forest soil (Hapludult) were determined at several locations in a spruce stand separately according to their origin (global fallout or Chernobyl fallout). To determine the rate of migration of these radionuclides in each soil horizon, the observed depth profiles of the radionuclides were evaluated with a compartment model. In the top organic horizons (LOf1 and Of2), the migration rates for all radionuclides from both sources were above 0.5 cm per year. In the Oh horizon the migration rates observed for global fallout Pu, Am and Cs were similar (0.2-0.4 cm per year). Compared with Pu, however, the mobility of Am is slightly, but statistically significantly, enhanced. The highest rate in this layer was found for Chernobyl-derived radiocaesium (2 cm per year). In the layers of the mineral horizon (depth 0-2, 2-5 and 5-10 cm) the observed migration rates were very similar for global fallout Pu (0.08-0.7 cm per year) and Am (0.1-2 cm per year). In comparison, the migration rate of global fallout radiocaesium was about half in each layer. The highest rate was observed again for Chernobyl-derived radiocaesium (0.5-3 cm per year).

  6. Effects of Mulching on Soil Properties and Growth of Tea Olive (Osmanthus fragrans).

    PubMed

    Ni, Xue; Song, Weiting; Zhang, Huanchao; Yang, Xiulian; Wang, Lianggui

    2016-01-01

    Different mulches have variable effects on soil physical properties and plant growth. This study aimed to compare the effects of mulching with inorganic (round gravel, RG), organic (wood chips, WC), and living (manila turf grass, MG) materials on soil properties at 0-5-cm and 5-10-cm depths, as well as on the growth and physiological features of Osmanthus fragrans L. 'Rixianggui' plants. Soil samples were collected at three different time points from field plots of O. fragrans plants treated with the different mulching treatments. Moisture at both soil depths was significantly higher after mulching with RG and WC than that in the unmulched control (CK) treatment. Mulching did not affect soil bulk density, pH, or total nitrogen content, but consistently improved soil organic matter. The available nitrogen in the soil increased after RG and WC treatments, but decreased after MG treatment during the experimental period. Mulching improved plant growth by increasing root activity, soluble sugar, and chlorophyll a content, as well as by providing suitable moisture conditions and nutrients in the root zone. Plant height and trunk diameter were remarkably increased after mulching, especially with RG and WC. However, while MG improved plant growth at the beginning of the treatment, the 'Rixianggui' plants later showed no improvement in growth. This was probably because MG competed with the plants for water and available nitrogen in the soil. Thus, our findings suggest that RG and WC, but not MG, improved the soil environment and the growth of 'Rixianggui' plants. Considering the effect of mulching on soil properties and plant growth and physiology, round gravel and wood chips appear to be a better choice than manila turf grass in 'Rixianggui' nurseries. Further studies are required to determine the effects of mulch quality and mulch-layer thickness on shoot and root growths.

  7. Effects of Mulching on Soil Properties and Growth of Tea Olive (Osmanthus fragrans).

    PubMed

    Ni, Xue; Song, Weiting; Zhang, Huanchao; Yang, Xiulian; Wang, Lianggui

    2016-01-01

    Different mulches have variable effects on soil physical properties and plant growth. This study aimed to compare the effects of mulching with inorganic (round gravel, RG), organic (wood chips, WC), and living (manila turf grass, MG) materials on soil properties at 0-5-cm and 5-10-cm depths, as well as on the growth and physiological features of Osmanthus fragrans L. 'Rixianggui' plants. Soil samples were collected at three different time points from field plots of O. fragrans plants treated with the different mulching treatments. Moisture at both soil depths was significantly higher after mulching with RG and WC than that in the unmulched control (CK) treatment. Mulching did not affect soil bulk density, pH, or total nitrogen content, but consistently improved soil organic matter. The available nitrogen in the soil increased after RG and WC treatments, but decreased after MG treatment during the experimental period. Mulching improved plant growth by increasing root activity, soluble sugar, and chlorophyll a content, as well as by providing suitable moisture conditions and nutrients in the root zone. Plant height and trunk diameter were remarkably increased after mulching, especially with RG and WC. However, while MG improved plant growth at the beginning of the treatment, the 'Rixianggui' plants later showed no improvement in growth. This was probably because MG competed with the plants for water and available nitrogen in the soil. Thus, our findings suggest that RG and WC, but not MG, improved the soil environment and the growth of 'Rixianggui' plants. Considering the effect of mulching on soil properties and plant growth and physiology, round gravel and wood chips appear to be a better choice than manila turf grass in 'Rixianggui' nurseries. Further studies are required to determine the effects of mulch quality and mulch-layer thickness on shoot and root growths. PMID:27508410

  8. Numerical Analysis of coupled liquid water, water vapor and heat transport in a sandy loam soil

    NASA Astrophysics Data System (ADS)

    Shukla, M. K.; Deb, S.; Sharma, P.

    2009-12-01

    Water vapor transport could be significant in arid areas such as southern New Mexico. Temporal soil moisture variations in unsaturated soils due to temperature gradients are characterized by the water vapor transport in the surface soil layer as liquid water movement could be very small especially when surface soil moisture is low. Numerical model Hydrus-1D was applied to investigate non-isothermal liquid and vapor flow closely coupled with the heat transport in a furrow-irrigated onion field located at Leyendecker Plant Science Research Center, Las Cruces. TDR and temperature sensors were installed to continuously monitor diurnal soil moisture and temperature variations in sandy loam onion beds at 5, 10, 20, and 50 cm depths during the entire growing season. Meteorological data were obtained from PSRC weather station. Hydrus-1D simulated soil moisture and temperature favorably contrasted against measured data at different depths. Simulations indicated that both liquid and vapor fluxes contributed to the water transport near surface. Liquid flux dominated the water movement during an irrigation event, while contribution of vapor flux increased with increasing soil drying. Vapor flux decreased from 5 cm to 25 cm depth, indicating that water vapor flux is much higher in the layer near soil surface. Both diffusive and dispersive transports are responsible for the vapor flux in the near-surface dry zone, while convective liquid flux was the main transport mechanism in the near-surface wet lower zone. In near-surface wet zone, diffusive flux decreased and changed from upward to downward flux.

  9. PROCESS OF PRODUCING Cm$sup 244$ AND Cm$sup 24$$sup 5$

    DOEpatents

    Manning, W.M.; Studier, M.H.; Diamond, H.; Fields, P.R.

    1958-11-01

    A process is presented for producing Cm and Cm/sup 245/. The first step of the process consists in subjecting Pu/sup 2339/ to a high neutron flux and subsequently dissolving the irradiated material in HCl. The plutonium is then oxidized to at least the tetravalent state and the solution is contacted with an anion exchange resin, causing the plutonium values to be absorbed while the fission products and transplutonium elements remain in the effluent solution. The effluent solution is then contacted with a cation exchange resin causing the transplutonium, values to be absorbed while the fission products remain in solution. The cation exchange resin is then contacted with an aqueous citrate solution and tbe transplutonium elements are thereby differentially eluted in order of decreasing atomic weight, allowing collection of the desired fractions.

  10. Harvesting impact on herbaceous understory, forest floor and top soil properties on skid road in a beech (Fagus orientalis Lipsky) stand.

    PubMed

    Demir, Murat; Makineci, E; Yilmaz, E

    2007-04-01

    In this study the impact of production work on the skid roads that have been carried out for many years by manpower animal power or machinery in a beech (Fagus orientalis Lipsky) stand have been examined. For this purpose, herbaceous understory, forest floor and soil samples were collected from the undisturbed area and the skid road. Weight per unit area (kg ha(-1)), organic matter ratio and moisture of forest floor and herbaceous understory were measured in undisturbed area and the skid road. Soil characteristics were examined at two different depths (0-5 cm and 5-10 cm). Percentages of sand, silt and clay electrical conductivity, weight of fine soil (<2 mm), soil fraction (>2 mm), root mass, organic carbon, moisture equivalent, total porosity, bulk density, moisture, compaction and pH values in the soil were determined. It has been determined that the amount of herbaceous understory and forest floor on the skid road decreased considerably compared to those of the undisturbed area. Parallel to this, the amount of organic matter in the herbaceous understory and the forest floor on the skid road decreased as well. It has been concluded that there are crucial differences between the values of compaction, bulk density fine soil weight, total porosity and moisture equivalent of the soil samples collected from both the skid road and the undisturbed area at both depth levels, as a result of compaction of the soil caused by harvesting works. PMID:17929761

  11. Salinity altered root distribution and increased diversity of bacterial communities in the rhizosphere soil of Jerusalem artichoke.

    PubMed

    Yang, Hui; Hu, Jinxiang; Long, Xiaohua; Liu, Zhaopu; Rengel, Zed

    2016-01-01

    The interaction between roots and bacterial communities in halophytic species is poorly understood. Here, we used Jerusalem artichoke cultivar Nanyu 1 (NY-1) to characterise root distribution patterns and determine diversity and abundance of bacteria in the rhizosphere soil under variable salinity. Root growth was not inhibited within the salinity range 1.2 to 1.9 g salt/kg, but roots were mainly confined to 0-20 cm soil layer vertically and 0-30 cm horizontally from the plant centre. Root concentrations of K(+), Na(+), Mg(2+) and particularly Ca(2+) were relatively high under salinity stress. High salinity stress decreased soil invertase and catalase activity. Using a next-generation, Illumina-based sequencing approach, we determined higher diversity of bacteria in the rhizosphere soil at high than low salinity. More than 15,500 valid reads were obtained, and Proteobacteria, Acidobacteria, Bacteroidetes and Actinobacteria predominated in all samples, accounting for >80% of the reads. On a genus level, 636 genera were common to the low and high salinity treatments at 0-5 cm and 5-10cm depth. The abundance of Steroidobacter and Sphingomonas was significantly decreased by increasing salinity. Higher Shannon and Chao 1 indices with increasing severity of salt stress indicated that high salt stress increased diversity in the bacterial communities. PMID:26852800

  12. Soil moisture content assessment based on Landsat 8 red, near-infrared, and thermal channels

    NASA Astrophysics Data System (ADS)

    Mobasheri, Mohammad Reza; Amani, Meisam

    2016-04-01

    Soil moisture content (SMC) plays an important role in different environmental. In this study, four different soil moisture indices, namely, SOMID, SOMID-FS, SOMID-FT, and CSOMID-FT, were introduced. In this work, the following parameters were used to estimate SMC at a depth of 5 cm: (a) the distance of pixels from the origin in the scatter-plot of near-infrared (NIR) and red bands (SNIR-R), (b) the fraction of soil cover in each pixel, and (c) the land surface temperature. It was concluded that the CSOMID-FT was the most accurate index for estimation of SMC (RMSE=0.045, R=0.92). This index divides the SNIR-R into three separate regions based on the pixels' normalized difference vegetation index (NDVI) values and assigns a specific regression equation to each region. The results showed that as the NDVI values increase, the accuracy of the proposed indices decreases. Furthermore, the SOMID-FT and CSOMID-FT were used to estimate SMC at five different depths of 5, 10, 20, 50, and 100 cm. It was concluded that the satellite-estimated SMC was highly correlated with the field-measured data at 5-cm soil depth.

  13. Soil moisture content assessment based on Landsat 8 red, near-infrared, and thermal channels

    NASA Astrophysics Data System (ADS)

    Mobasheri, Mohammad Reza; Amani, Meisam

    2016-04-01

    Soil moisture content (SMC) plays an important role in different environmental. In this study, four different soil moisture indices, namely, SOMID, SOMID-FS, SOMID-FT, and CSOMID-FT, were introduced. In this work, the following parameters were used to estimate SMC at a depth of 5 cm: (a) the distance of pixels from the origin in the scatter-plot of near-infrared (NIR) and red bands (SNIR-R), (b) the fraction of soil cover in each pixel, and (c) the land surface temperature. It was concluded that the CSOMID-FT was the most accurate index for estimation of SMC (RMSE=0.045, R=0.92). This index divides the SNIR-R into three separate regions based on the pixels' normalized difference vegetation index (NDVI) values and assigns a specific regression equation to each region. The results showed that as the NDVI values increase, the accuracy of the proposed indices decreases. Furthermore, the SOMID-FT and CSOMID-FT were used to estimate SMC at five different depths of 5, 10, 20, 50, and 100 cm. It was concluded that the satellite-estimated SMC was highly correlated with the field-measured data at 5-cm soil depth.

  14. Uptake of 244Cm, 238Pu and other radionuclides by trees inhabiting a contaminated flood plain.

    PubMed

    Pinder, J E; McLeod, K W; Alberts, J J; Adriano, D C; Corey, J C

    1984-09-01

    The plant uptake of 244Cm, 137Cs, 238Pu and 90Sr was measured for trees in a flood plain forest whose soils were contaminated by aqueous discharges from a nuclear-fuel chemical separations facility. Uptake of the naturally occurring radionuclide 226Ra was also measured. The relative availability of the nuclides was 238Pu less than 244Cm less than 137Cs less than 226Ra less than or equal to 90Sr. The concentration ratios for 238Pu and 244Cm, 3 X 10(-4) and 3.6 X 10(-3), respectively, were similar to those reported for other plant-soil systems. The ratios for 137Cs and 90Sr, 0.11 and 3.9, were similar to those reported for other southeastern soils. However, the ratio for 226Ra, 2.1, was greater than that normally reported. These ratios, which were determined in the field, were generally similar to those reported for greenhouse studies on the same soil.

  15. Weekly cycle of magnetic characteristics of PM2.5 and PM2.5-10 in Beijing, China

    NASA Astrophysics Data System (ADS)

    SHI, M.; Wu, H.; Zhang, S.; Li, H.; Yang, T.

    2013-12-01

    In urban areas,fine particle matter with aerodynamic diameter between 2.5 um and 10 um (PM2.5-10), and 2.5 um (PM2.5), as an important source of urban particulate matter (PM) pollutants, have significant negative effects on health, atmospheric visibility and climate. PM has increasingly become a significant index of indicating the atmospheric pollution of city. In recent years, Beijing, China has been listed as one of the most serious air pollution city in the world. In order to investigate the sources of air pollutants, a total of 283 pairs of PM2.5 and PM2.5-10 samples were collected daily from July, 2010 to June, 2011 in Beijing. Mineral magnetic properties and Scanning electron microscope (SEM) observations and energy dispersive X-ray spectroscopy (EDS) analyses of PM2.5 and PM2.5-10 were measured to verify the magnetic materials. Magnetic measures for PM indicated that the major magnetic phase was coarse-grained magnetite-like material. The χlf, χarm, SIRM and χarm/SIRM series of the PM2.5 and PM2.5-10 show seasonal dependences: high values in winter and low values in summer. In additional the parameters analyzed by Time-series methods show a strong cycle about 7 days above 95% confidence level. Weekly cycle of magnetic characteristics of PM2.5 and PM2.5-10 show different pattern: the concentration of magnetic particles in PM2.5-10 show high values in mid-week, and particle sizes is steady, while the concentration of magnetic particles in PM2.5 show reverse a weekly cycle pattern, and particle sizes is smaller in the mid-week.Microscopy analyses reveal basically three morphologies of magnetic grains: aggregate, spherules and angular particles. The ultrafine carbonaceous particles which tend to form complex clusters and chain-like structures, most likely come from coal burning and motor vehicle exhaust. Spherical particles in PM2.5 are dominantly composed of Fe, O and C, grain-diameters of particles range from 0.3 to 2 um. Angular particles of Fe

  16. Water movement through an experimental soil liner

    USGS Publications Warehouse

    Krapac, I.G.; Cartwright, K.; Panno, S.V.; Hensel, B.R.; Rehfeldt, K.R.; Herzog, B.L.

    1991-01-01

    break through at the base of the liner occurs. Estimated saturated hydraulic conductivities were 2.5 ?? 10-9, 4.0 ?? 10-8, and 5.0 ?? 10-8 cm s-1 based on measurements of water infiltration into the liner by large- and small-ring infiltrometers and a water balance analysis, respectively. Also investigated in this research was the variability of the liner's hydraulic properties and estimates of the transit times for water and tracers. Small variances exhibited by small-ring flux data suggested that the liner was homogeneous with respect to infiltration fluxes. The predictions of water and tracer breakthrough at the base of the liner ranged from 2.4-12.6 y, depending on the method of calculation and assumptions made. The liner appeared to be saturated to a depth between 18 and 33 cm at the end of the first year of monitoring. Transit time calculations cannot be verified yet, since breakthrough has not occurred. The work conducted so far indicates that compacted soil barriers can be constructed to meet the saturated hydraulic conductivity requirement established by the U.S. EPA.

  17. Dissipation kinetics of pre-plant pesticides in greenhouse-devoted soils.

    PubMed

    López-Fernández, O; Rial-Otero, R; Simal-Gándara, J; Boned, J

    2016-02-01

    This work was conducted to study the distribution of methyl isothiocyanate (MITC) in greenhouse soils treated with the fumigant dazomet (DZ) from the formulated product "Basamid Granular(®)", but also of 1,3-dichloropropene (1,3-D) and chloropicrin (CP) from the fumigant "Agrocelhone NE(®)". In order to achieve this aim, several methods for the determination of fumigants residues in soils, but also pepper fruits were optimized and characterized. With independence of the soil depth, no residues of MITC, 1,3-D and CP above the detection limits were observed in soils covered with a polyethylene (PE) film (0.04 mm thick) after 27, 13 and 8 days of treatment, respectively. Liberation and dissipation curves of MITC in soil in presence of a PE film (0.04 mm) used to limit volatilization losses were also obtained. According to the results, the rate of decomposition of DZ into MITC have a half-life of 3.7 days in the surface horizon (5-10 cm) of the soil while in the subsurface horizon (15-20 cm), MITC formation rate is slightly slow (half-life of 3.2 days). With respect to the dissipation process, half-lives lower than 1 day were obtained for both depths (0.8 and 0.9 for the surface and the subsurface horizon, respectively). In the case of 1,3-D and CP in soil, the dissipation half-life of 1,3-D on soils was a bit higher than for CP (2 days vs. 1). In addition, the presence of residues of the fumigants on green pepper fruits grown on the treated soils was not detected as expected. PMID:26575632

  18. Changes in Fungal Community Composition in Response to Elevated Atmospheric CO2 and Nitrogen Fertilization Varies with Soil Horizon.

    PubMed

    Weber, Carolyn F; Vilgalys, Rytas; Kuske, Cheryl R

    2013-01-01

    Increasing levels of atmospheric carbon dioxide (CO2) and rates of nitrogen (N)-deposition to forest ecosystems are predicted to alter the structure and function of soil fungal communities, but the spatially heterogeneous distribution of soil fungi has hampered investigations aimed at understanding such impacts. We hypothesized that soil physical and chemical properties and fungal community composition would be differentially impacted by elevated atmospheric CO2 (eCO2) and N-fertilization in spatially separated field samples, in the forest floor, 0-2, 2-5, and 5-10cm depth intervals in a loblolly pine Free-Air Carbon Dioxide Enrichment (FACE) experiment. In all soils, quantitative PCR-based estimates of fungal biomass were highest in the forest floor. Fungal richness, based on pyrosequencing of the fungal ribosomal large subunit gene, increased in response to N-fertilization in 0-2 cm and forest floor intervals. Composition shifted in forest floor, 0-2 and 2-5 cm intervals in response to N-fertilization, but the shift was most distinct in the 0-2 cm interval, in which the largest number of statistically significant changes in soil chemical parameters (i.e., phosphorus, organic matter, calcium, pH) was also observed. In the 0-2 cm interval, increased recovery of sequences from the Thelephoraceae, Tricholomataceae, Hypocreaceae, Clavicipitaceae, and Herpotrichiellaceae families and decreased recovery of sequences from the Amanitaceae correlated with N-fertilization. In this same depth interval, Amanitaceae, Tricholomataceae, and Herpotriciellaceae sequences were recovered less frequently from soils exposed to eCO2 relative to ambient conditions. These results demonstrated that vertical stratification should be taken into consideration in future efforts to elucidate environmental impacts on fungal communities and their feedbacks on ecosystem processes.

  19. Effects of short term bioturbation by common voles on biogeochemical soil variables.

    PubMed

    Wilske, Burkhard; Eccard, Jana A; Zistl-Schlingmann, Marcus; Hohmann, Maximilian; Methler, Annabel; Herde, Antje; Liesenjohann, Thilo; Dannenmann, Michael; Butterbach-Bahl, Klaus; Breuer, Lutz

    2015-01-01

    Bioturbation contributes to soil formation and ecosystem functioning. With respect to the active transport of matter by voles, bioturbation may be considered as a very dynamic process among those shaping soil formation and biogeochemistry. The present study aimed at characterizing and quantifying the effects of bioturbation by voles on soil water relations and carbon and nitrogen stocks. Bioturbation effects were examined based on a field set up in a luvic arenosol comprising of eight 50 × 50 m enclosures with greatly different numbers of common vole (Microtus arvalis L., ca. 35-150 individuals ha-1 mth-1). Eleven key soil variables were analyzed: bulk density, infiltration rate, saturated hydraulic conductivity, water holding capacity, contents of soil organic carbon (SOC) and total nitrogen (N), CO2 emission potential, C/N ratio, the stable isotopic signatures of 13C and 15N, and pH. The highest vole densities were hypothesized to cause significant changes in some variables within 21 months. Results showed that land history had still a major influence, as eight key variables displayed an additional or sole influence of topography. However, the δ15N at depths of 10-20 and 20-30 cm decreased and increased with increasing vole numbers, respectively. Also the CO2 emission potential from soil collected at a depth of 15-30 cm decreased and the C/N ratio at 5-10 cm depth narrowed with increasing vole numbers. These variables indicated the first influence of voles on the respective mineralization processes in some soil layers. Tendencies of vole activity homogenizing SOC and N contents across layers were not significant. The results of the other seven key variables did not confirm significant effects of voles. Thus overall, we found mainly a first response of variables that are indicative for changes in biogeochemical dynamics but not yet of those representing changes in pools. PMID:25954967

  20. Effects of short term bioturbation by common voles on biogeochemical soil variables.

    PubMed

    Wilske, Burkhard; Eccard, Jana A; Zistl-Schlingmann, Marcus; Hohmann, Maximilian; Methler, Annabel; Herde, Antje; Liesenjohann, Thilo; Dannenmann, Michael; Butterbach-Bahl, Klaus; Breuer, Lutz

    2015-01-01

    Bioturbation contributes to soil formation and ecosystem functioning. With respect to the active transport of matter by voles, bioturbation may be considered as a very dynamic process among those shaping soil formation and biogeochemistry. The present study aimed at characterizing and quantifying the effects of bioturbation by voles on soil water relations and carbon and nitrogen stocks. Bioturbation effects were examined based on a field set up in a luvic arenosol comprising of eight 50 × 50 m enclosures with greatly different numbers of common vole (Microtus arvalis L., ca. 35-150 individuals ha-1 mth-1). Eleven key soil variables were analyzed: bulk density, infiltration rate, saturated hydraulic conductivity, water holding capacity, contents of soil organic carbon (SOC) and total nitrogen (N), CO2 emission potential, C/N ratio, the stable isotopic signatures of 13C and 15N, and pH. The highest vole densities were hypothesized to cause significant changes in some variables within 21 months. Results showed that land history had still a major influence, as eight key variables displayed an additional or sole influence of topography. However, the δ15N at depths of 10-20 and 20-30 cm decreased and increased with increasing vole numbers, respectively. Also the CO2 emission potential from soil collected at a depth of 15-30 cm decreased and the C/N ratio at 5-10 cm depth narrowed with increasing vole numbers. These variables indicated the first influence of voles on the respective mineralization processes in some soil layers. Tendencies of vole activity homogenizing SOC and N contents across layers were not significant. The results of the other seven key variables did not confirm significant effects of voles. Thus overall, we found mainly a first response of variables that are indicative for changes in biogeochemical dynamics but not yet of those representing changes in pools.

  1. Polynomial response of 2,4-D mineralization to temperature in soils at varying soil moisture contents, slope positions and depths.

    PubMed

    Shymko, Janna L; Farenhorst, Annemieke; Zvomuya, Francis

    2011-01-01

    The herbicide 2,4-D [2,4-(dichlorophenoxy) acetic acid] is a widely used broadleaf control agent in cereal production systems. Although 2,4-D soil-residual activity (half-lives) are typically less than 10 days, this herbicide also has as a short-term leaching potential due to its relatively weak retention by soil constituents. Herbicide residual effects and leaching are influenced by environmental variables such as soil moisture and temperature. The objective of this study was to determine impacts of these environmental variables on the magnitude and extent of 2,4-D mineralization in a cultivated undulating Manitoba prairie landscape. Microcosm incubation experiments were utilized to assess 2,4-D half-lives and total mineralization using a 4 × 4 × 3 × 2 factorial design (with soil temperature at 4 levels: 5, 10, 20 and 40°C; soil moisture at 4 levels: 60, 85, 110, 135 % of field capacity; slope position at 3 levels: upper-, mid- and lower-slopes; and soil depth at 2 levels: 0-5 cm and 5-15 cm). Half-lives (t(½)) varied from 3 days to 51 days with the total 2,4-D mineralization (M(T)) ranging from 5.8 to 50.9 %. The four-way interaction (temperature × moisture × slope × depth) significantly (p < 0.001) influenced both t(½) and M(T). Second-order polynomial equations best described the relations of temperature with t(½) and M(T) as was expected from a biological system. However, the interaction and variability of t(½) and M(T) among different temperatures, soil moistures, slope positions, and soil depth combinations indicates that the complex nature of these interacting factors should be considered when applying 2,4-D in agricultural fields and in utilizing these parameters in pesticide fate models. PMID:21500076

  2. Polynomial response of 2,4-D mineralization to temperature in soils at varying soil moisture contents, slope positions and depths.

    PubMed

    Shymko, Janna L; Farenhorst, Annemieke; Zvomuya, Francis

    2011-01-01

    The herbicide 2,4-D [2,4-(dichlorophenoxy) acetic acid] is a widely used broadleaf control agent in cereal production systems. Although 2,4-D soil-residual activity (half-lives) are typically less than 10 days, this herbicide also has as a short-term leaching potential due to its relatively weak retention by soil constituents. Herbicide residual effects and leaching are influenced by environmental variables such as soil moisture and temperature. The objective of this study was to determine impacts of these environmental variables on the magnitude and extent of 2,4-D mineralization in a cultivated undulating Manitoba prairie landscape. Microcosm incubation experiments were utilized to assess 2,4-D half-lives and total mineralization using a 4 × 4 × 3 × 2 factorial design (with soil temperature at 4 levels: 5, 10, 20 and 40°C; soil moisture at 4 levels: 60, 85, 110, 135 % of field capacity; slope position at 3 levels: upper-, mid- and lower-slopes; and soil depth at 2 levels: 0-5 cm and 5-15 cm). Half-lives (t(½)) varied from 3 days to 51 days with the total 2,4-D mineralization (M(T)) ranging from 5.8 to 50.9 %. The four-way interaction (temperature × moisture × slope × depth) significantly (p < 0.001) influenced both t(½) and M(T). Second-order polynomial equations best described the relations of temperature with t(½) and M(T) as was expected from a biological system. However, the interaction and variability of t(½) and M(T) among different temperatures, soil moistures, slope positions, and soil depth combinations indicates that the complex nature of these interacting factors should be considered when applying 2,4-D in agricultural fields and in utilizing these parameters in pesticide fate models.

  3. Structure and stability of H+ associates of (5,10,15,20-tetraphenylporphinato)silver(II) in trifluoroacetic acid

    NASA Astrophysics Data System (ADS)

    Bichan, N. G.; Tyulyaeva, E. Yu.; Lomova, T. N.

    2014-08-01

    Direct experimental confirmation of the formation of ion-molecular associates of (5,10,15,20-tetraphenyl-21H,23H-porphinato)silver(II) (AgTPP) with solvent protons in CF3COOH is obtained by means of 1H NMR spectroscopy. Their structure and spectral properties, as well as the kinetics of dissociation on metal-nitrogen bonds, depending on the concentration of CF3COOH (89-100%) and temperature (298-328 K), are studied It is shown that AgTPP acts as a C-base during the formation of H+ associates, the coordination centers of which have a high stability.

  4. Changes in biogeochemistry of pyrogenic carbon in soil after one year

    NASA Astrophysics Data System (ADS)

    Singh, N.; Abiven, S.; Maestrini, B.; Bird, J. A.; Eoin, E. L.; Torn, M. S.; Schmidt, M. W. I.

    2012-04-01

    Pyrogenic carbon (PyC), incomplete combustion product of biomass and fossil fuel, is ubiquitous in the environment and widely assumed to remain stable in soil (1). The stability of PyC has been challenged by a series of recent laboratory and field experiments (2-4), which show that it is mineralized slowly to CO2 in soil. We are carrying out a long-term PyC degradation study within an experimental field setup located at Laegeren forest (Wettingen, Switzerland). We have installed cylindrical mesocosms (20 cm long and 10 cm diameter) in a randomized block design with 3 plots, 3 treatments (wood, PyC, and control) and 2 levels of nitrogen (N) input (+N = +60 kg ha-1 y-1 and -N = ambient N deposition). Wood (Pinus ponderosa) and PyC were highly labelled (13C 800‰ and 15N 4.2 atom%) and were added at a rate of 1.5 g-C kg-1 soil and 2.8 g-C kg-1 soil, respectively. We observed that PyC decomposed at a rate of 0.64 % year-1. We extracted the mesocosms after ca. 10 months in situ and sampled soil at different column depths (0-5, 5-10, 10-15 cm). We carried out δ13C and δ15N analysis to estimate the total recovery of the added substrate and its transport within the soil profile inside the mesocosms. The benzenepolycarboxylic acid (BPCA) molecular marker method was employed to quantify and characterize the PyC before and after its addition into the soil. Density fractionation was applied to identify organo-mineral interactions and understand the dynamics of PyC degradation in soil. We analysed soil sub-samples for microbial biomass using fumigation -extraction. We further study the effect of PyC on soil enzyme to determine if PyC could modify soil biological properties. We observed that after 10 months in the soil, 1) the quality of PyC, estimated by relative contribution of individual BPCA molecular markers, remained unchanged; 2) PyC showed negligible vertical movement within the soil profile; 3) most PyC was in free and occluded particulate fractions (22% PyC in

  5. [Soil carbon and nitrogen sequestration following cropland to forage grassland conversion in the marginal land in the middle of Heihe River basin, northwest China].

    PubMed

    Su, Yong-zhong

    2006-07-01

    Changes in soil organic carbon (SOC) and total nitrogen (TN) stocks were studied following croplands were converted to forage grasslands (alfalfa) for five years on the marginal land at the edge of oasis in the middle reaches of Heihe river basin. Soil from 12 paired forage land/adjacent cropland on the two soil types (Typic Torripsamments and Typic Calciorthids) was sampled at the three depths of 0-5, 5-10 and 10-20 cm and analyzed for SOC and TN, particulate organic carbon (POC) and nitrogen (PON). The studied soils had very low SOC and N concentrations. SOC stock at the 0-20 cm depth increased by 22.1%-27.8% after conversion of annually crop to perennial alfalfa for four years, and carbon sequestration rate was estimated to be on average 0.47 Mg/(hm2 x a). The greatest change in SOC stock occurred at the 0-5 cm surface layer with an increase of 32%-66%. No significant TN stock was found at the 0-20 cm depth, however, it increased at the 0-5 cm surface layer by 12.8% and 48.1% for Typic Torripsamments and Typic Calciorthids, respectively. Changes in POC and PON stocks were more significant than those in SOC and total N following conversion of crop to forage, and the percentage of distributions of POC and PON increased. POC and PON stocks at the 0-20 cm depth increased by 22.8%-42.7% and 18.6%-57.6% with the greatest increases at the 0-5 cm layer. The increase in soil C pool was mainly attributed to the increase of POC formation after the marginal lands converted to perennial forage cover. Typic Calciorthids with lower SOC concentration had relatively lower C sequestration rate but more significant effects of C and N sequestration compared with Typic Torripsamments.

  6. Effects of Wheat Straw Incorporation on the Availability of Soil Nutrients and Enzyme Activities in Semiarid Areas

    PubMed Central

    Wei, Ting; Zhang, Peng; Wang, Ke; Ding, Ruixia; Yang, Baoping; Nie, Junfeng; Jia, Zhikuan; Han, Qingfang

    2015-01-01

    Soil infertility is the main barrier to dryland agricultural production in China. To provide a basis for the establishment of a soil amelioration technical system for rainfed fields in the semiarid area of northwest China, we conducted a four—year (2007–2011) field experiment to determine the effects of wheat straw incorporation on the arid soil nutrient levels of cropland cultivated with winter wheat after different straw incorporation levels. Three wheat straw incorporation levels were tested (H: 9000 kg hm-2, M: 6000 kg hm-2, and L: 3000 kg hm-2) and no straw incorporation was used as the control (CK). The levels of soil nutrients, soil organic carbon (SOC), soil labile organic carbon (LOC), and enzyme activities were analyzed each year after the wheat harvest. After straw incorporation for four years, the results showed that variable straw amounts had different effects on the soil fertility indices, where treatment H had the greatest effect. Compared with CK, the average soil available N, available P, available K, SOC, and LOC levels were higher in the 0–40 cm soil layers after straw incorporation treatments, i.e., 9.1–30.5%, 9.8–69.5%, 10.3–27.3%, 0.7–23.4%, and 44.4–49.4% higher, respectively. On average, the urease, phosphatase, and invertase levels in the 0–40 cm soil layers were 24.4–31.3%, 9.9–36.4%, and 42.9–65.3% higher, respectively. Higher yields coupled with higher nutrient contents were achieved with H, M and L compared with CK, where these treatments increased the crop yields by 26.75%, 21.51%, and 7.15%, respectively. PMID:25880452

  7. Drug Resistance of Enteric Bacteria VI. Introduction of Bacteriophage P1CM into Salmonella typhi and Formation of P1dCM and F-CM Elements

    PubMed Central

    Kondo, Eiko; Mitsuhashi, Susumu

    1966-01-01

    Kondo, Eiko (Gunma University, Maebashi, Japan), and Susumu Mitsuhashi. Drug resistance of enteric bacteria. VI. Introduction of bacteriophage P1CM into Salmonella typhi and formation of P1dCM and F-CM elements. J. Bacteriol. 91:1787–1794. 1966.—Bacteriophage P1CM was introduced into Salmonella typhi by means of both phage infection and conjugation with Escherichia coli F+ lysogenic for the phage. Upon incubation with a P1CM phage lysate, S. typhi and S. abony yield CMr cells which are lysogenic for P1CM, but S. typhimurium LT2 does not. The P1CM phage is adsorbed slightly to S. typhi, but no infectious centers are formed when the phage is plated on this strain. Tests on P1CM-adsorbing capacity of the S. typhi P1CM+ strain and on plaque formation and transduction ability of the recovered phage from this strain indicated that the cell and the phage population did not have any special advantage over the original cell and phage population. Conjugation of S. typhi with E. coli F+ carrying P1CM+ gave three types of S. typhi CMr clones: those which carry the whole P1CM phage, those with the P1dCM element, and those with nontransferable CMr. The second type has the F factor and is sensitive to f phages in spite of its typical behavior, serologically and biochemically, as S. typhi. It can donate the P1dCM and F+ characters to E. coli F− or F−/P1 strains. As a consequence of conjugation with the E. coli F+ strain, the CMr character of the third type of S. typhi, the nontransferable CMr element, acquired conjugational transferability, owing to the formation of the element, F-CM. This element can be transferred to an E. coli F− strain at a very high frequency (ca. 100). Both the F and CMr determinants are jointly transduced with P1 phage and are jointly eliminated by acridine dye treatment. PMID:5327907

  8. Effects of soil temperature and snow cover on the mortality of overwintering pupae of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae).

    PubMed

    Huang, Jian

    2016-07-01

    Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is one of the most damaging insect pests in the world. However, little is known about the effects of snow cover and soil temperature on the overwintering pupae of H. armigera. A field experiment was conducted from November 2, 2012 to April 24, 2013 at the agrometeorological experimental station in Wulanwusu, China. Overwintering pupae were embedded into the soil at depths of 5, 10, and 15 cm in the following four treatments: without snow cover, snow cover, and increased temperatures from 600 and 1200 W infrared lights. The results showed that snow cover and rising temperatures could all markedly increase soil temperatures, which was helpful in improving the survival of the overwintering pupae of H. armigera. The mortality of overwintering pupae (MOP) at a depth of 15 cm was the highest, and the MOP at a depth of 5 cm followed. The lower accumulated temperature (≤0 °C) (AT ≤ °C) led to the higher MOP, and the lower diurnal soil temperature range (DSTR) likely led to the lower MOP. After snowmelt, the MOPs at the depths of 5 and 10 cm increased as the soil temperature increased, especially in April. The AT of the soil (≤0 °C) was the factor with the strongest effect on MOP. The soil moisture content was not a major factor affecting the MOP in this semiarid region because precipitation was 45 mm over the entire experimental period. With climate warming, the MOP will likely decrease, and the overwintering boundary air temperatures of H. armigera should be expanded due to higher soil temperatures and increased snow cover.

  9. Effects of soil temperature and snow cover on the mortality of overwintering pupae of the cotton bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

    NASA Astrophysics Data System (ADS)

    Huang, Jian

    2016-07-01

    Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is one of the most damaging insect pests in the world. However, little is known about the effects of snow cover and soil temperature on the overwintering pupae of H. armigera. A field experiment was conducted from November 2, 2012 to April 24, 2013 at the agrometeorological experimental station in Wulanwusu, China. Overwintering pupae were embedded into the soil at depths of 5, 10, and 15 cm in the following four treatments: without snow cover, snow cover, and increased temperatures from 600 and 1200 W infrared lights. The results showed that snow cover and rising temperatures could all markedly increase soil temperatures, which was helpful in improving the survival of the overwintering pupae of H. armigera. The mortality of overwintering pupae (MOP) at a depth of 15 cm was the highest, and the MOP at a depth of 5 cm followed. The lower accumulated temperature (≤0 °C) (AT ≤ °C) led to the higher MOP, and the lower diurnal soil temperature range (DSTR) likely led to the lower MOP. After snowmelt, the MOPs at the depths of 5 and 10 cm increased as the soil temperature increased, especially in April. The AT of the soil (≤0 °C) was the factor with the strongest effect on MOP. The soil moisture content was not a major factor affecting the MOP in this semiarid region because precipitation was 45 mm over the entire experimental period. With climate warming, the MOP will likely decrease, and the overwintering boundary air temperatures of H. armigera should be expanded due to higher soil temperatures and increased snow cover.

  10. Short-term transport of glyphosate with erosion in Chinese loess soil--a flume experiment.

    PubMed

    Yang, Xiaomei; Wang, Fei; Bento, Célia P M; Xue, Sha; Gai, Lingtong; van Dam, Ruud; Mol, Hans; Ritsema, Coen J; Geissen, Violette

    2015-04-15

    Repeated applications of glyphosate may contaminate the soil and water and threaten their quality both within the environmental system and beyond it through water erosion related processes and leaching. In this study, we focused on the transport of glyphosate and its metabolite aminomethylphosphonic acid (AMPA) related to soil erosion at two slope gradients (10 and 20°), two rates of pesticide with a formulation of glyphosate (Roundup®) application (360 and 720 mg m(-2)), and a rain intensity of 1.0 mm min(-1) for 1 h on bare soil in hydraulic flumes. Runoff and erosion rate were significantly different within slope gradients (p<0.05) while suspended load concentration was relatively constant after 15 min of rainfall. The glyphosate and AMPA concentration in the runoff and suspended load gradually decreased. Significant power and exponent function relationship were observed between rainfall duration and the concentration of glyphosate and AMPA (p<0.01) in runoff and suspended load, respectively. Meanwhile, glyphosate and AMPA content in the eroded material depended more on the initial rate of application than on the slope gradients. The transport rate of glyphosate by runoff and suspended load was approximately 14% of the applied amount, and the chemicals were mainly transported in the suspended load. The glyphosate and AMPA content in the flume soil at the end of the experiment decreased significantly with depth (p<0.05), and approximately 72, 2, and 3% of the applied glyphosate (including AMPA) remained in the 0-2, 2-5, and 5-10 cm soil layers, respectively. The risk of contamination in deep soil and the groundwater was thus low, but 5% of the initial application did reach the 2-10 cm soil layer. The risk of contamination of surface water through runoff and sedimentation, however, can be considerable, especially in regions where rain-induced soil erosion is common.

  11. Short-term transport of glyphosate with erosion in Chinese loess soil--a flume experiment.

    PubMed

    Yang, Xiaomei; Wang, Fei; Bento, Célia P M; Xue, Sha; Gai, Lingtong; van Dam, Ruud; Mol, Hans; Ritsema, Coen J; Geissen, Violette

    2015-04-15

    Repeated applications of glyphosate may contaminate the soil and water and threaten their quality both within the environmental system and beyond it through water erosion related processes and leaching. In this study, we focused on the transport of glyphosate and its metabolite aminomethylphosphonic acid (AMPA) related to soil erosion at two slope gradients (10 and 20°), two rates of pesticide with a formulation of glyphosate (Roundup®) application (360 and 720 mg m(-2)), and a rain intensity of 1.0 mm min(-1) for 1 h on bare soil in hydraulic flumes. Runoff and erosion rate were significantly different within slope gradients (p<0.05) while suspended load concentration was relatively constant after 15 min of rainfall. The glyphosate and AMPA concentration in the runoff and suspended load gradually decreased. Significant power and exponent function relationship were observed between rainfall duration and the concentration of glyphosate and AMPA (p<0.01) in runoff and suspended load, respectively. Meanwhile, glyphosate and AMPA content in the eroded material depended more on the initial rate of application than on the slope gradients. The transport rate of glyphosate by runoff and suspended load was approximately 14% of the applied amount, and the chemicals were mainly transported in the suspended load. The glyphosate and AMPA content in the flume soil at the end of the experiment decreased significantly with depth (p<0.05), and approximately 72, 2, and 3% of the applied glyphosate (including AMPA) remained in the 0-2, 2-5, and 5-10 cm soil layers, respectively. The risk of contamination in deep soil and the groundwater was thus low, but 5% of the initial application did reach the 2-10 cm soil layer. The risk of contamination of surface water through runoff and sedimentation, however, can be considerable, especially in regions where rain-induced soil erosion is common. PMID:25644837

  12. Elemental concentration analysis in soil contaminated with recyclable urban garbage by tube-excited energy-dispersive X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Anjos, M. J.; Lopes, R. T.; Jesus, E. F. O.; Assis, J. T.; Cesareo, R.; Barroso, R. C.; Barradas, C. A. A.

    2002-11-01

    Soil and radish (Raphanus Sp) samples from areas treated with organic compost of recyclable urban garbage were quantitatively analyzed by using tube-excited energy-dispersive X-ray fluorescence analysis. Soils treated with 10, 20 and 30 t/ha of recyclable urban garbage and control soil were analyzed. The layer soils were collected at 0-5, 5-10, 10-20, 20-40, 40-60 cm depth. It was possible simultaneously to determine the elemental concentration of various elements: K, Ca, Ti, Mn, Fe, Cu, Zn, Br, Rb, Sr, Zr and Pb in recyclable urban garbage, soil treated with organic compost of recyclable urban garbage and radish plants cultivated in these soils. The elemental concentration of K, Ca, Ti and Fe were determined at percent level (macro-elements) and the other elements at ppm level (micro-elements). It was also possible to observe a significant increase in the contents of K, Ca, Zn, Rb, Sr, Zr and Pb in the soil treated in comparison with the control soil and it was also verified whether the transport of these elements to radish plants cultivated in these soils occurred.

  13. Changes in Soil Temperature Regimes under Regional Climate Change

    NASA Astrophysics Data System (ADS)

    Millar, S. W.

    2013-12-01

    Soil temperatures can provide a smoothed record of regional changes in atmospheric conditions due to soil thermal properties that reduce the annual air and surface temperature amplitude. In areas with seasonal snow cover, however, its insulating effect isolates the soil thermal regime from winter air temperatures. Under changing regional climate patterns, snow cover extent, depth and duration are decreasing. The net effect is thus an expected winter cooling of soil temperature. However, the extent to which this might be mitigated by warmer summer conditions, and changing soil moisture remains to be seen. To examine the relative strength of a cold-season cooling signal versus enhanced summer warming, a network of soil temperature loggers has recorded hourly soil temperatures over the period 2005-2013 within a single watershed experiencing 'lake effect snow'. Elevations range from 168 m to 612 m, on Silurian and Ordovician shale, limestone, and sandstone that have been heavily glaciated. Most of the sites are located on NY Department of Environmental Conservation land in mixed, hardwood and spruce forests. At six sites in varied topographic and land-use setting, two ONSET HOBO Outdoor 4 channel soil temperature loggers are deployed in order to reduce concerns of data reliability and systematic logger drift. Five sites also record air temperature using HOBO Pro Series Temperature loggers at three sites and HOBO Weather Stations at two. Soil temperature data are recorded at hourly intervals at depths of 2-, 5-, 10-, and 25-cm. Several other sites have been operationalized over the 8 year period, but have been tampered with, damaged, stolen, or have failed. These partial records are included to provide greater geographic representation of changing conditions where possible. Data indicate decreasing winter soil temperatures in specific land-use and topographic settings. Only one site, located in a dense spruce plantation, experiences soil freezing within the top 5 cm

  14. Dryland soil microbial communities display spatial biogeographic patterns associated with soil depth and soil parent material

    USGS Publications Warehouse

    Steven, Blaire; Gallegos-Graves, La Verne; Belnap, Jayne; Kuske, Cheryl R.

    2013-01-01

    Biological soil crusts (biocrusts) are common to drylands worldwide. We employed replicated, spatially nested sampling and 16S rRNA gene sequencing to describe the soil microbial communities in three soils derived from different parent material (sandstone, shale, and gypsum). For each soil type, two depths (biocrusts, 0–1 cm; below-crust soils, 2–5 cm) and two horizontal spatial scales (15 cm and 5 m) were sampled. In all three soils, Cyanobacteria and Proteobacteria demonstrated significantly higher relative abundance in the biocrusts, while Chloroflexi and Archaea were significantly enriched in the below-crust soils. Biomass and diversity of the communities in biocrusts or below-crust soils did not differ with soil type. However, biocrusts on gypsum soil harbored significantly larger populations of Actinobacteria and Proteobacteria and lower populations of Cyanobacteria. Numerically dominant operational taxonomic units (OTU; 97% sequence identity) in the biocrusts were conserved across the soil types, whereas two dominant OTUs in the below-crust sand and shale soils were not identified in the gypsum soil. The uniformity with which small-scale vertical community differences are maintained across larger horizontal spatial scales and soil types is a feature of dryland ecosystems that should be considered when designing management plans and determining the response of biocrusts to environmental disturbances.

  15. Method of using 5,10,15,20-tetrakis(carboxyphenyl)porphine for detecting cancers of the lung

    DOEpatents

    Cole, D.A.; Moody, D.C. III; Ellinwood, L.E.; Klein, M.G.

    1992-11-10

    A method is described for using tetra-aryl porphyrins for and, in particular, 5,10,15,20-tetrakis(4-carboxyphenyl)porphine as a fluorescent tracer for cancers of the lung, and as a radiotracer therefor as a complex with [sup 67]Cu. The latter complex also provides a source of beta radiation for selective destruction of lung malignancies as well as gamma radiation useful for image analysis of the lungs by single photon emission computed tomography, as an example, both in vivo. Copper-64 may be substituted for the [sup 67]Cu if only radiotracer characteristics are of interest. This lighter isotope of copper is a positron emitter, and positron emission tomography techniques can be used to locate the malignant tissue mass. 1 figure.

  16. Method using 5,10,15,20-tetrakis(4-carboxyphenyl)porphine for treating cancers of the lung

    DOEpatents

    Cole, Dean A.; Moody, III, David C.; Ellinwood, L. Edward; Klein, M. Gerard

    1995-01-01

    Method using tetra-aryl porphyrins for and, in particular, 5,10,15,20-tetrakis(4-carboxyphenyl)porphine as a fluorescent tracer for cancers of the lung, and as a radiotracer therefor as a complex with .sup.67 Cu. The latter complex also provides a source of beta radiation for selective destruction of lung malignancies as well as gamma radiation useful for image analysis of the situs thereof by single photon emission computed tomography, as an example, both in vivo. Copper-64 may be substituted for the .sup.67 Cu if only radiotracer characteristics are of interest. This lighter isotope of copper is a positron emitter, and positron emission tomography techniques can be used to locate the malignant tissue mass.

  17. Method of using 5,10,15,20-tetrakis(carboxyphenyl)porphine for detecting cancers of the lung

    DOEpatents

    Cole, Dean A.; Moody, III, David C.; Ellinwood, L. Edward; Klein, M. Gerard

    1992-01-01

    Method using tetra-aryl porphyrins for and, in particular, 5,10,15,20-tetrakis(4-carboxyphenyl)porphine as a fluorescent tracer for cancers of the lung, and as a radiotracer therefor as a complex with .sup.67 Cu. The latter complex also provides a source of beta radiation for selective destruction of lung malignancies as well as gamma radiation useful for image analysis of the situs thereof by single photon emission computed tomography, as an example, both in vivo. Copper-64 may be substituted for the .sup.67 Cu if only radiotracer characteristics are of interest. This lighter isotope of copper is a positron emitter, and positron emission tomography techniques cna be used to locate the malignant tissue mass.

  18. Presence of the 5,10-methylenetetrahydrofolate reductase C677T mutation in Puerto Rican patients with neural tube defects.

    PubMed

    García-Fragoso, Lourdes; García-García, Inés; de la Vega, Alberto; Renta, Jessicca; Cadilla, Carmen L

    2002-01-01

    Folic acid supplementation can reduce the incidence of neural tube defects. The first reported genetic risk factor for neural tube defects is a C677T mutation in the 5,10-methylenetetrahydrofolate reductase gene, resulting in decreased activity of the enzyme. We examined the enzyme mutation role of methylenetetrahydrofolate reductase in the etiology of neural tube defects in our population. The study group consisted of 204 Puerto Rican individuals including 37 pregnant females with a prenatal diagnosis of neural tube defects in their fetuses, 31 newborns, 36 fathers, and 100 healthy adults. The prevalence of the C677T mutation was examined. Homozygosity for the alanine to valine substitution (TT) was observed in 9% of the controls and 19% of the mothers with children with neural tube defects. Our results indicate that the presence of the T allele at the methylenetetrahydrofolate reductase 677 position may increase the risk of giving birth to an infant with a neural tube defect.

  19. Impact of grain storage into silo bags on soil penetration resistance

    NASA Astrophysics Data System (ADS)

    Hernández, Juan Pablo; Alé, Daniel; Sabattini, Rafael; Díaz, Eduardo; Lado, Marcos; González, Antonio Paz

    2015-04-01

    Big silo sacks or bags ("silo bolsas", in Spanish) are nowadays widely used in Argentina as an innovative technology for grain storage and conservation on the farm. Following the last harvest campaigns, 40.000.000 Toms of grains were stored in silo sacks. A standard silo sack, or silo bag, has a length of about 75 m and is 2.7 m in diameter; when laden with cereal grains, a pressure of 9.8 MPa is applied on the soil surface. Silo sacks are currently installed within agricultural fields, and, after the storage period has finished, the plot they occupied most commonly again is cultivated. The aim of this study was to assess the effect of silo sacks on soil penetration resistance (PR). Two field experiments were performed in sites located at the departments of Paraná and Nogoyá, Entre Ríos province, Argentina. The soils in both sites were classified as Vertisols and contained expansible smectite minerals, mainly montmorillonite. Soil PR was continuously recorded until 80 cm depth. The first experiment, conducted in Paraná department, involved three different treatments with five RP replicated measurements per treatment: a) a plot under a silo bag with regular machinery transit for grain uploading and downloading, and previously used as pasture for livestock, b) a plot under grassland used for mowing and without livestock transit, and c) a plot under woody native vegetation, locally called "Espinal". The second experiment, conducted at Nogoyá department consisted of two treatments, each with for PR replications: a) a plot under silo sack with machinery transit, and b) a control plot located in the neighbouring field. n the first site a significant increase in soil PR (P<0,05) under silo bag was recorded at the 0-20cm depth. In the second site soil PR was not significantly different between treatments at the 0-5 cm depth, while significant differences in PR were recorded at the 5-10 cm depth (P<0.05). We concluded that soil PR measurements under silo bag provide

  20. Copper Accumulation, Availability and Adsorption Capacity in Sandy Soils of Vineyards with Different Cultivation Duration

    NASA Astrophysics Data System (ADS)

    Mallmann, F. J. K.; Miotto, A.; Bender, M. A.; Gubiani, E.; Rheinheimer, D. D. S.; Kaminski, J.; Ceretta, C. A.; Šimůnek, J.

    2015-12-01

    Bordeaux mixture is a copper-based (Cu) fungicide and bactericide applied in vineyards to control plant diseases. Since it is applied several times per year, it accumulates in large quantities on plants and in soil. This study evaluates the Cu accumulation in, and desorption kinetics and adsorption capability of a sandy Ultisol in a natural field and in 3 vineyards for 5 (V1), 11 (V2), and 31 (V3) years in South of Brazil. Soil samples were collected in 8 depths (0-60 cm) of all four soil profiles, which all displayed similar soil properties. The following soil properties were measured: pH, organic matter (OM), soil bulk density, Cu total concentration, and Cu desorption and adsorption curves. A two first-order reactions model and the Langmuir isotherm were fitted to the desorption and adsorption curves, respectively. An increase in the total mass of Cu in the vineyards followed a linear regression curve, with an average annual increase of 7.15 kg ha-1. Cu accumulated down to a depth of 5, 20, and 30 cm in V1, V2 and V3, respectively, with the highest Cu content reaching 138.4 mg kg-1 in the 0-5 cm soil layer of V3. Cu desorption parameters showed a high correlation with its total concentration. Approximately 57 and 19% of total Cu were immediately and slowly available, respectively, indicating a high potential for plant absorption and/or downward movement. Cu concentrations extracted by EDTA from soil layers not affected by anthropogenic Cu inputs were very low. The maximum Cu adsorption capacity of the 0-5 and 5-10 cm soil layers increased with the vineyard age, reaching concentrations higher than 900 mg kg-1. This increase was highly related to OM and pH, which both increased with cultivation duration. Despite of low clay content of these soils, there is low risk of groundwater Cu contamination for actual conditions. However, high Cu concentrations in the surface layer of the long-term vineyards could cause toxicity problems for this and for companion crops.

  1. Treatment of the edentulous atrophic maxilla using zygomatic implants: evaluation of survival rates over 5-10 years.

    PubMed

    Yates, J M; Brook, I M; Patel, R R; Wragg, P F; Atkins, S A; El-Awa, A; Bakri, I; Bolt, R

    2014-02-01

    The aim of this retrospective observational cohort study was to analyse and report the 5-10-year survival rates of endosseous zygomatic implants used in the rehabilitation of the atrophic maxilla. Forty-three consecutive zygomatic implant placements in 25 patients were evaluated over a 5-10-year period. All zygomatic implant surgery was carried out under general anaesthesia. Nobel Biocare zygomatic machined-surface implants were used, and placement was undertaken using the modified sinus slot method. The main outcome measures and determinants for success were survival of the restored implants and the proportion of originally planned prostheses delivered to patients. Of the 25 patients treated, 12 were male and 13 were female; 19 were non-smokers, and the mean age at time of surgery was 64 years. Patients were treatment-planned for implant-retained bridgework, a removable prosthesis retained by fixed cast gold or milled titanium beams, or magnet-retained removable prostheses. A combination of zygomatic and conventional implants was used in all but one patient. In this study it was shown that the overall success rate for zygomatic implants was 86%, with six of the implants either failing to integrate or requiring removal due to persistent infection associated with the maxillary sinus. All patients received their planned prosthesis, although in six cases the method of retention required modification. This study illustrates that zygomatic implants are a successful and important treatment option when trying to restore the atrophic maxilla, with the potential to avoid additional augmentation/grafting procedures and resulting in a high long-term success rate. PMID:24120903

  2. Aggregate breakdown and surface seal development influenced by rain intensity, slope gradient and soil particle size

    NASA Astrophysics Data System (ADS)

    Arjmand Sajjadi, S.; Mahmoodabadi, M.

    2014-12-01

    Aggregate breakdown is an important process which controls infiltration rate (IR) and the availability of fine materials necessary for structural sealing under rainfall. The purpose of this study was to investigate the effects of different slope gradients, rain intensities and particle size distributions on aggregate breakdown and IR to describe the formation of surface sealing. To address this issue, 60 experiments were carried out in a 35 cm x 30 cm x 10 cm detachment tray using a rainfall simulator. By sieving a sandy loam soil, two sub-samples with different maximum aggregate sizes of 2 mm (Dmax 2 mm) and 4.75 mm (Dmax 4.75 mm) were prepared. The soils were exposed to two different rain intensities (57 and 80 mm h-1) on several slopes (0.5, 2.5, 5, 10, and 20%) each at three replications. The result showed that the most fraction percentages in soils Dmax 2 mm and Dmax 4.75 mm were in the finest size classes of 0.02 and 0.043 mm, respectively for all slope gradients and rain intensities. The soil containing finer aggregates exhibited higher transportability of pre-detached material than the soil containing larger aggregates. Also, IR increased with increasing slope gradient, rain intensity and aggregate size under unsteady state conditions because of less development of surface seal. But under steady state conditions, no significant relationship was found between slope and IR. The finding of this study revealed the importance of rain intensity, slope steepness and soil aggregate size on aggregate breakdown and seal formation, which can control infiltration rate and the consequent runoff and erosion rates.

  3. Soil spreading of liquid olive mill processing wastes impacts leaching of adsorbed terbuthylazine.

    PubMed

    Aharonov-Nadborny, R; Raviv, M; Graber, E R

    2016-08-01

    Olive mill waste water (OMWW) is a major byproduct of the three phase olive oil production process. OMWW has high acidity (pH ∼ 4-5), high salt content (EC ∼ 5-10 mS cm(-1)), extremely high biological and chemical oxygen demand (BOD and COD up to 100,000 and 220,000 mg L(-1), respectively), and also high concentrations of organic compounds such as phenols and polyphenols. As a result, OMWW cannot be freely discharged into domestic wastewater treatment plants, but on-site treatment is very expensive and not sufficiently effective. Uses for OMWW such as agricultural recycling and co-composting were found to be impractical or expensive. Thus, OMWW is frequently spread on agricultural land for disposal. However, excessive or uncontrolled spreading of such organic-rich and saline wastewater could have many deleterious effects on soil quality, including salinization, phytotoxicity, or contaminant movement. The impact of OMWW on the leaching of adsorbed terbuthylazine, a soil-applied herbicide, was tested in four soils of varying physical and chemical properties. Although terbuthylazine solubility in OMWW is significantly higher than in water, leaching of adsorbed terbuthylazine from OMWW-treated soils was less than from control treatments. Low soil organic carbon and clay contents were major factors that contributed to reduced terbuthylazine leaching after soil treatment with OMWW.

  4. Soil spreading of liquid olive mill processing wastes impacts leaching of adsorbed terbuthylazine.

    PubMed

    Aharonov-Nadborny, R; Raviv, M; Graber, E R

    2016-08-01

    Olive mill waste water (OMWW) is a major byproduct of the three phase olive oil production process. OMWW has high acidity (pH ∼ 4-5), high salt content (EC ∼ 5-10 mS cm(-1)), extremely high biological and chemical oxygen demand (BOD and COD up to 100,000 and 220,000 mg L(-1), respectively), and also high concentrations of organic compounds such as phenols and polyphenols. As a result, OMWW cannot be freely discharged into domestic wastewater treatment plants, but on-site treatment is very expensive and not sufficiently effective. Uses for OMWW such as agricultural recycling and co-composting were found to be impractical or expensive. Thus, OMWW is frequently spread on agricultural land for disposal. However, excessive or uncontrolled spreading of such organic-rich and saline wastewater could have many deleterious effects on soil quality, including salinization, phytotoxicity, or contaminant movement. The impact of OMWW on the leaching of adsorbed terbuthylazine, a soil-applied herbicide, was tested in four soils of varying physical and chemical properties. Although terbuthylazine solubility in OMWW is significantly higher than in water, leaching of adsorbed terbuthylazine from OMWW-treated soils was less than from control treatments. Low soil organic carbon and clay contents were major factors that contributed to reduced terbuthylazine leaching after soil treatment with OMWW. PMID:27179239

  5. Spatiotemporal variability of soil hydrological properties and its implication on small catchments hydrology

    NASA Astrophysics Data System (ADS)

    Ferreira, C. S. S.; Steenhuis, T. S.; Soares, D.; Ferreira, A. J. D.; Coelho, C. O. A.; Walsh, R. P. D.

    2012-04-01

    The increasing population pressure on the environment implies changes to land use and to landscape patterns within catchments, with impacts on hydrological processes. Some of the changes are linked to soil properties modification, directly disturbing water infiltration and runoff generation processes, which affects local and regional water resources. Although there has been considerable research on soil properties, few studies focused its spatial and temporal variability at the catchment scale and how they affect hydrology. In this paper, we aim to assess the spatial and temporal variability of water repellence, soil moisture and water infiltration, in a small catchment under Mediterranean climate. The study was carried out at Ribeira dos Covões, a small catchment (620ha) located in central Portugal. This is a partly urbanizing catchment, where the urban landuse covers 32% of the area, while the forest represent 48% and farmland 20%. The catchment has a sub-humid Mediterranean climate, with long dry summers. The soil is deep overlaying sandstone and limestone lithology. Thirty one representative sites were monitored within the catchment. Each site has two replicated experiments for water infiltration (performed during 30 minutes, through minidisk tension infiltrometer at the soil surface), soil moisture content (at 0-5cm depth, by gravimetric method) and soil water repellence (assessed at 0cm, 2cm and 5cm depth through ethanol percentage test). These experiments were carried out along one entire year, during nine monitoring campaigns performed in dry and wet periods, mainly immediately after different rainfall events and long dry spells. During one of the monitoring campaigns, undisturbed soil samples were collected (0-10cm depth) in all the location sites for bulk density and stone content analyses. Composite samples were also collected from the top soil layer (0-5cm and 5-10cm) for organic content (by measuring carbon dioxide emission after combustion at 1200

  6. Lessons Learned From CM-2 Modal Testing and Analysis

    NASA Technical Reports Server (NTRS)

    McNelis, Mark E.; Goodnight, Thomas W.; Carney, Kelly S.; Otten, Kim D.

    2002-01-01

    The Combustion Module-2 (CM-2) is a space experiment that launches on Shuttle mission STS-107 in the SPACEHAB Double Research Module. The CM-2 flight hardware is installed into SPACEHAB single and double racks. The CM-2 flight hardware was vibration tested in the launch configuration to characterize the structure's modal response. Cross-orthogonality between test and analysis mode shapes were used to assess model correlation. Lessons learned for pre-test planning and model verification are discussed.

  7. Energy Levels of the Nitrate Radical Below 2000 CM-1

    NASA Astrophysics Data System (ADS)

    Stanton, J. F.; Simmons, C. S.

    2012-06-01

    Highly sophisticated quantum chemistry techniques have been employed to build a three-state diabatic Hamiltonian for the nitrate radical (NO_3). Eigenvalues of this Hamiltonian (which includes effects beyond the Born-Oppenheimer approximation) are consistent with the known ``vibrational'' levels of NO_3 up to ca. 2100 cm-1 above the zero-point level; with a small empirical adjustment of the diabatic coupling strength, calculated levels are within 20 cm-1 of the measured level positions for those that have been observed experimentally. Of the eleven states with e' symmetry calculated below 2000 cm-1, nine of these have been observed either in the gas phase by Hirota and collaborators as well as Neumark and Johnston, or in frozen argon by Jacox. However, the Hamiltonian produces two levels that have not been seen experimentally: one calculated to lie at 1075 cm-1 (which is the third e' state, above ν_4 and 2ν_4) and another at 1640 cm-1 which is best assigned as one of the two e' sublevels of 4ν_4. A significant result is that the state predicted at 1075 cm-1 is not far enough above the predicted 2ν_4 level (777 cm-1 v. ca. 760 cm-1 from experiment) to be plausibly assigned as 3ν_4 (which is at 1155 cm-1: experimental position: 1173 cm-1), nor is its nodal structure consistent with such an idea. Rather, it is quite unambiguously the ν_3 level. Given the fidelity of the results generated by this model Hamiltonian as compared to experiment, it can safely be concluded that the prominent infrared band seen at 1492 cm-1 (corresponding to a calculated level at 1500 cm-1) is not ν_3, but rather a multiquantum state best viewed as a sublevel of the ν_3 + ν_4 combination.

  8. Soil warming increased whole-tree water use of Pinus cembra at the treeline in the Central Tyrolean Alps.

    PubMed

    Wieser, Gerhard; Grams, Thorsten E E; Matyssek, Rainer; Oberhuber, Walter; Gruber, Andreas

    2015-03-01

    This study quantified the effect of soil warming on sap flow density (Qs) of Pinus cembra L. at the treeline in the Central Tyrolean Alps. To enhance soil temperature we installed a transparent roof construction above the forest floor around six trees. Six other trees served as controls in the absence of any manipulation. Roofing enhanced growing season mean soil temperature by 1.6, 1.3 and 1.0 °C at 5, 10 and 20 cm soil depth, respectively, while soil water availability was not affected. Sap flow density (using Granier-type thermal dissipation probes) and environmental parameters were monitored throughout three growing seasons. During the first year of treatment, no warming effect was detected on Qs. However, soil warming caused Qs to increase significantly by 11 and 19% above levels in control trees during the second and third year, respectively. This effect appeared to result from warming-induced root production, a reduction in viscosity and perhaps an increase also in root hydraulic conductivity. Hardly affected were leaf-level net CO2 uptake rate and conductance for water vapour, so that water-use efficiency stayed unchanged as confirmed by needle δ(13)C analysis. We conclude that tree water loss will increase with soil warming, which may alter the water balance within the treeline ecotone of the Central Austrian Alps in a future warming environment.

  9. INCREASED AIRWAYS INFLAMMATION AND MODIFIED BAL CELL SURFACE PHENOTYPES IN ASTHMATICS EXPOSED TO COARSE SIZE (PM2.5-10) CONCENTRATED AMBIENT PARTICLES (CAPS)

    EPA Science Inventory

    Although associations between inhalation of PM10 and disease morbidity and mortality appear stronger for fine (PM2.5) vs coarse (PM2.5-10) or ultrafine/UF (PM<0.1) PM. In vitro studies suggest that PM2.5-10 are more potent in inducing pro-inflammatory cytokine responses from alve...

  10. Effects of electron irradiation and temperature on 1 ohm-cm and 10 ohm-cm silicon solar cells

    NASA Technical Reports Server (NTRS)

    Nicoletta, C. A.

    1973-01-01

    One OHM-cm and 10 OHM-cm silicon solar cells were exposed to 1.0 MeV electrons at a fixed flux of 10 to the 11th power e/sq cm/sec and fluences of 10 to the 13th power, 10 to the 14th power and 10 to the 15th power e/sq.cm. 1-V curves of the cells were made at room temperature, - 63 C and + or - 143 C after each irradiation. A value of 139.5 mw/sq cm was used as AMO incident energy rate per unit area. The 10 OHM-cm cells appear more efficient than 1 OHM-cm cells after exposure to a fluence greater than 10 to the 14th power e/sq cm. The 1.0 MeV electron damage coefficients for both 1 OHM-cm and 10 OHM-cm cells are somewhat less than those for previously irradiated cells at room temperature. The values of the damage coefficients increase as the cell temperatures decrease. Efficiencies pertaining to maximum power output are about the same as those of n on p silicon cells evaluated previously.

  11. Heavy metal enrichment in the riparian sediments and soils of the Three Gorges Reservoir, China

    NASA Astrophysics Data System (ADS)

    Tang, Q.; Bao, Y.; He, X.; Wen, A.

    2015-03-01

    The Three Gorges Reservoir encompasses a riparian zone with a vertical height of 30 m and a total area of 349 km2 that has been subjected to alternate inundation and exposure due to regular impoundment. Sedimentation on the riparian landforms constitutes an important pathway for riverine contaminant redistribution. In an attempt to understand heavy metal enrichment since water inundation, riparian sediments and soils were sampled along five transects in a typical riparian zone composed of cultivated bench terraces in the middle reaches. Heavy metals (Cr, Ni, Cu, Zn, As, Cd and Pb) were determined to characterize the lateral distribution and vertical transfer ratio. The results indicated that all heavy metals were enriched to varying extents both in the riparian sediments and soils, compared with regional background contents in soils and the reference levels in sediments. However, heavy metal levels in the riparian sediments were generally higher than those in the riparian soils, while those in the upper riparian soils (0-5 cm) were overall slightly higher than those in the lower riparian soils (5-10 cm). There was a decreasing trend of heavy metal contents with increasing elevation. The elevated levels of heavy metals in the riparian sediments may be attributed to sediment yields from upstream anthropogenic sources, especially during major rainstorms in the wet season when large loads of contaminated sediment may be produced from diffuse source areas. Heavy metals can also be adsorbed to pure sediment in the course of mobilization or after deposition. Considering that the riparian soils are local weathering products without mobilization, the enrichment of heavy metals may principally be ascribed to chemical adsorption from dissolved fractions or vertical transfer from overlaid sediments. Heavy metal enrichment may further be affected by the specific type of hydrologic regime such that relatively long flooding duration caused by water impoundment and natural floods

  12. Effect of multivitamins on plasma homocysteine in patients with the 5,10 methylenetetrahydrofolate reductase C677T homozygous state.

    PubMed

    Dell'edera, Domenico; Tinelli, Andrea; Milazzo, Giusi Natalia; Malvasi, Antonio; Domenico, Carone; Pacella, Elena; Pierluigi, Compagnoni; Giuseppe, Tarantino; Marcello, Guido; Francesco, Lomurno; Epifania, Annunziata Anna

    2013-08-01

    The role of hyperhomocysteinemia (HHcy) as a cardiovascular risk factor remains a matter of debate, while it correlates with folates, it demonstrates inverse correlation with plasma homocysteine (Hcy) levels and vitamin B12 levels and reduces plasma Hcy levels following supplementation with multivitamins. The purpose of this study was to demonstrate that administering multivitamins at specific doses for 90 days restores normal plasma Hcy levels in women who are homozygous for the thermolabile variant of 5,10 methylenetetrahydrofolate reductase (MTHFR C677T). We enrolled 106 healthy females aged between 30 and 42 years, who were non-smokers, non-vegetarian, normotensive and who had no history of food abuse in the previous months. Only females were enrolled in order to rule out any bias due to the variation in Hcy plasma concentrations between males and females. Patient blood sampling was performed in order to determine plasma Hcy, serum folic acid and vitamin B12 levels. Furthermore, molecular characterization of the C677T polymorphism present in the MTHFR gene, was also performed. The results of this study demonstrated that supplementation with specific multivitamins restores normal plasma Hcy levels, regardless of the MTHFR genotype. Furthermore, it is unnecessary to adminster high doses of folate to reduce plasma Hcy levels, and administering high doses of folate may cause pro-inflammatory and pro-proliferative effects. PMID:23818036

  13. Microwave soft x-ray microscopy for nanoscale magnetization dynamics in the 5-10 GHz frequency range.

    PubMed

    Bonetti, Stefano; Kukreja, Roopali; Chen, Zhao; Spoddig, Detlef; Ollefs, Katharina; Schöppner, Christian; Meckenstock, Ralf; Ney, Andreas; Pinto, Jude; Houanche, Richard; Frisch, Josef; Stöhr, Joachim; Dürr, Hermann A; Ohldag, Hendrik

    2015-09-01

    We present a scanning transmission x-ray microscopy setup combined with a novel microwave synchronization scheme for studying high frequency magnetization dynamics at synchrotron light sources. The sensitivity necessary to detect small changes in the magnetization on short time scales and nanometer spatial dimensions is achieved by combining the excitation mechanism with single photon counting electronics that is locked to the synchrotron operation frequency. Our instrument is capable of creating direct images of dynamical phenomena in the 5-10 GHz range, with high spatial resolution. When used together with circularly polarized x-rays, the above capabilities can be combined to study magnetic phenomena at microwave frequencies, such as ferromagnetic resonance (FMR) and spin waves. We demonstrate the capabilities of our technique by presenting phase resolved images of a ∼6 GHz nanoscale spin wave generated by a spin torque oscillator, as well as the uniform ferromagnetic precession with ∼0.1° amplitude at ∼9 GHz in a micrometer-sized cobalt strip. PMID:26429444

  14. DNA Physical Mapping via the Controlled Translocation of Single Molecules through a 5-10nm Silicon Nitride Nanopore

    NASA Astrophysics Data System (ADS)

    Stein, Derek; Reisner, Walter; Jiang, Zhijun; Hagerty, Nick; Wood, Charles; Chan, Jason

    2009-03-01

    The ability to map the binding position of sequence-specific markers, including transcription-factors, protein-nucleic acids (PNAs) or deactivated restriction enzymes, along a single DNA molecule in a nanofluidic device would be of key importance for the life-sciences. Such markers could give an indication of the active genes at particular stage in a cell's transcriptional cycle, pinpoint the location of mutations or even provide a DNA barcode that could aid in genomics applications. We have developed a setup consisting of a 5-10 nm nanopore in a 20nm thick silicon nitride film coupled to an optical tweezer setup. The translocation of DNA across the nanopore can be detected via blockades in the electrical current through the pore. By anchoring one end of the translocating DNA to an optically trapped microsphere, we hope to stretch out the molecule in the nanopore and control the translocation speed, enabling us to slowly scan across the genome and detect changes in the baseline current due to the presence of bound markers.

  15. Solvent effect on the nonlinear absorption of 5,10-A(2)B(2) meso substituted porphyrins.

    PubMed

    Zawadzka, Monika; Wang, Jun; Blau, Werner J; Senge, Mathias O

    2013-10-01

    The effect of the solvent on the nonlinear absorptive properties of two series of 5,10-A2B2 porphyrins was investigated with an open Z-scan technique in the ns time regime. The recorded responses, which varied between compounds and solvents, were fitted to a four-level model where the one-photon excited state absorption is followed by a two-photon process arising from the higher excited states. For most of the compounds the positive nonlinear absorption in toluene was stronger than that in DMF and chloroform. This was attributed to enhanced two-photon absorption in toluene. For DMF and chloroform the solvent effects were most likely to be compound specific. It was demonstrated that the high saturation intensity of two-photon absorption shifts the RSA/SA turnover into a higher fluence range, which is desirable for optical limiting applications. This saturation intensity of two-photon absorption varied between compounds and solvents. Additionally, nonlinear scattering contributed strongly to the open Z-scan responses for many compounds in chlorobenzene and chloroform-chlorobenzene solutions. This was associated with the photodegradation of chlorobenzene.

  16. A Neptune-sized transiting planet closely orbiting a 5-10-million-year-old star

    NASA Astrophysics Data System (ADS)

    David, Trevor J.

    2016-10-01

    Theories of the formation and early evolution of planetary systems postulate that planets are born in circumstellar disks, and undergo radial migration during and after dissipation of the dust and gas disk from which they formed. The precise ages of meteorites indicate that planetesimals - the building blocks of planets - are produced within the first million years of a star's life. A prominent question is: how early can one find fully formed planets like those frequently detected on short orbital periods around mature stars? Some theories suggest the in situ formation of planets close to their host stars is unlikely and the existence of such planets is evidence for large scale migration. Other theories posit that planet assembly at small orbital separations may be common. Here we report on a newly-born, transiting planet orbiting its star every 5.4 days. The planet is 50 per cent larger than Neptune, and its mass is less than 3.6 times Jupiter (at 99.7 per cent confidence), with a true mass likely to be within a factor of several of Neptune's. The 5-10 million year old star has a tenuous dust disk extending outwards from about 2 times the Earth-Sun separation, in addition to the large planet located at less than one-twentieth the Earth-Sun separation.

  17. A Neptune-sized transiting planet closely orbiting a 5-10-million-year-old star

    NASA Astrophysics Data System (ADS)

    David, Trevor J.; Hillenbrand, Lynne A.; Petigura, Erik A.; Carpenter, John M.; Crossfield, Ian J. M.; Hinkley, Sasha; Ciardi, David R.; Howard, Andrew W.; Isaacson, Howard T.; Cody, Ann Marie; Schlieder, Joshua E.; Beichman, Charles A.; Barenfeld, Scott A.

    2016-06-01

    Theories of the formation and early evolution of planetary systems postulate that planets are born in circumstellar disks, and undergo radial migration during and after dissipation of the dust and gas disk from which they formed. The precise ages of meteorites indicate that planetesimals—the building blocks of planets—are produced within the first million years of a star’s life. Fully formed planets are frequently detected on short orbital periods around mature stars. Some theories suggest that the in situ formation of planets close to their host stars is unlikely and that the existence of such planets is therefore evidence of large-scale migration. Other theories posit that planet assembly at small orbital separations may be common. Here we report a newly born, transiting planet orbiting its star with a period of 5.4 days. The planet is 50 per cent larger than Neptune, and its mass is less than 3.6 times that of Jupiter (at 99.7 per cent confidence), with a true mass likely to be similar to that of Neptune. The star is 5-10 million years old and has a tenuous dust disk extending outward from about twice the Earth-Sun separation, in addition to the fully formed planet located at less than one-twentieth of the Earth-Sun separation.

  18. Stability and prediction of physical activity in 5-, 10-, and 28-year follow-up studies among industrial employees.

    PubMed

    Kirjonen, J; Telama, R; Luukkonen, R; Kääriä, S; Kaila-Kangas, L; Leino-Arjas, P

    2006-06-01

    The aim of the study was to examine the stability of voluntary and household physical activity (PA) and to compare it with that of the use of the most common stimulants. The prospective cohort study comprised of follow-ups at 5, 10, and 28 years at baseline in 1973 in four plants of an industrial corporation in Finland. A systematic, non-proportional sample (n=902, age range 18-64 years) stratified for age, gender, and occupational status was drawn from the employees. Scores of PA were based on a questionnaire and interviews. Logistic regression models with proportional odds assumptions were counted. The 5-year stability (Spearman's rho) of PA time was 0.44 (PA intensity 0.44), the respective 10-year coefficient was 0.26 (0.32), and that in the 28-year follow-up was 0.18 (0.20). The stability of PA decreased rapidly from 1973 to 1983 and more slowly thereafter. Changes along the follow-up reflect a polarization of the distributions of PA within the sample. Age and an initially low level of activity were the strongest predictors of inactivity. The stability coefficient of smoking and alcohol consumption was twice as high as that of PA. Stimulant use was a greater factor in the individual's lifestyle than PA. PMID:16643199

  19. Microwave soft x-ray microscopy for nanoscale magnetization dynamics in the 5-10 GHz frequency range

    NASA Astrophysics Data System (ADS)

    Bonetti, Stefano; Kukreja, Roopali; Chen, Zhao; Spoddig, Detlef; Ollefs, Katharina; Schöppner, Christian; Meckenstock, Ralf; Ney, Andreas; Pinto, Jude; Houanche, Richard; Frisch, Josef; Stöhr, Joachim; Dürr, Hermann A.; Ohldag, Hendrik

    2015-09-01

    We present a scanning transmission x-ray microscopy setup combined with a novel microwave synchronization scheme for studying high frequency magnetization dynamics at synchrotron light sources. The sensitivity necessary to detect small changes in the magnetization on short time scales and nanometer spatial dimensions is achieved by combining the excitation mechanism with single photon counting electronics that is locked to the synchrotron operation frequency. Our instrument is capable of creating direct images of dynamical phenomena in the 5-10 GHz range, with high spatial resolution. When used together with circularly polarized x-rays, the above capabilities can be combined to study magnetic phenomena at microwave frequencies, such as ferromagnetic resonance (FMR) and spin waves. We demonstrate the capabilities of our technique by presenting phase resolved images of a ˜6 GHz nanoscale spin wave generated by a spin torque oscillator, as well as the uniform ferromagnetic precession with ˜0.1° amplitude at ˜9 GHz in a micrometer-sized cobalt strip.

  20. The amino acid composition of the Sutter's Mill CM2 carbonaceous chondrite

    NASA Astrophysics Data System (ADS)

    Burton, Aaron S.; Glavin, Daniel P.; Elsila, Jamie E.; Dworkin, Jason P.; Jenniskens, Peter; Yin, Qing-Zhu

    2014-11-01

    We determined the abundances and enantiomeric compositions of amino acids in Sutter's Mill fragment #2 (designated SM2) recovered prior to heavy rains that fell April 25-26, 2012, and two other meteorite fragments, SM12 and SM51, that were recovered postrain. We also determined the abundance, enantiomeric, and isotopic compositions of amino acids in soil from the recovery site of fragment SM51. The three meteorite stones experienced terrestrial amino acid contamination, as evidenced by the low D/L ratios of several proteinogenic amino acids. The D/L ratios were higher in SM2 than in SM12 and SM51, consistent with rain introducing additional L-amino acid contaminants to SM12 and SM51. Higher percentages of glycine, β-alanine, and γ-amino-n-butyric acid were observed in free form in SM2 and SM51 compared with the soil, suggesting that these free amino acids may be indigenous. Trace levels of D+L-β-aminoisobutyric acid (β-AIB) observed in all three meteorites are not easily explained as terrestrial contamination, as β-AIB is rare on Earth and was not detected in the soil. Bulk carbon and nitrogen and isotopic ratios of the SM samples and the soil also indicate terrestrial contamination, as does compound-specific isotopic analysis of the amino acids in the soil. The amino acid abundances in SM2, the most pristine SM meteorite analyzed here, are approximately 20-fold lower than in the Murchison CM2 carbonaceous chondrite. This may be due to thermal metamorphism in the Sutter's Mill parent body at temperatures greater than observed for other aqueously altered CM2 meteorites.

  1. Effect of DTPA on concentration ratios of /sup 237/Np and /sup 244/Cm in vegetative parts of bush bean and barley

    SciTech Connect

    Romney, E.M.; Wallace, A.; Mueller, R.T.; Cha, J.W.; Wood, R.A.

    1981-07-01

    We grew bush beans, barley, and rice in two different soils in a glasshouse with /sup 237/Np or /sup 244/Cm mixed into separate containers of the soil. The chelating agent DTPA at 100 ..mu..g/g soil was added to half of the containers. The concentration ratio (CR) for /sup 237/Np without DTPA was two orders of magnitude higher than for /sup 244/Cm without DTPA for all three plant species. The DTPA increased the CR of /sup 244/Cm by two to three orders of magnitude, but had no influence on that for /sup 237/Np. In bush beans, both /sup 237/Np and /sup 244/Cm CRs were higher in primary leaves than in trifoliate leaves, which were higher than for stems. The CRs for bush beans were generally higher for both /sup 237/Np and /sup 244/Cm than for either barley or rice, especially without DTPA.

  2. "The 5 cm Rule": Biopower, Sexuality and Schooling

    ERIC Educational Resources Information Center

    Allen, Louisa

    2009-01-01

    This paper explores "the 5 cm rule", a regulation around student contact discovered during an investigation of the sexual culture of schooling with 16-19-year-olds in New Zealand. Implemented to stem "inappropriate and unwanted" touching, it stipulates that students must maintain a physical distance of 5 cm at all times. It is argued this rule…

  3. Design and Performance of 40 cm Ion Optics

    NASA Technical Reports Server (NTRS)

    Soulas, George C.

    2001-01-01

    A 40 cm ion thruster is being developed at the NASA Glenn Research Center to obtain input power and propellant throughput capabilities of 10 kW and 550 kg. respectively. The technical approach here is a continuation of the "derating" technique used for the NSTAR ion thruster. The 40 cm ion thruster presently utilizes the NSTAR ion optics aperture geometry to take advantage of the large database of lifetime and performance data already available. Dome-shaped grids were chosen for the design of the 40 cm ion optics because this design is naturally suited for large-area ion optics. Ion extraction capabilities and electron backstreaming limits for the 40 cm ion optics were estimated by utilizing NSTAR 30 cm ion optics data. A preliminary service life assessment showed that the propellant throughput goal of 550 kg of xenon may be possible with molybdenum 40 cm ion optics. One 40 cm ion optics' set has been successfully fabricated to date. Additional ion optics' sets are presently being fabricated. Preliminary performance tests were conducted on a laboratory model 40 cm ion thruster.

  4. Effects of proton irradiation and temperature on 1 ohm-cm and 10 ohm-cm silicon solar cells

    NASA Technical Reports Server (NTRS)

    Nicoletta, C. A.

    1973-01-01

    The 1 ohm-cm and 10 ohm-cm silicon solar cells were exposed to 1.0 MeV protons at a fixed flux of 10 to the 9th power P/sq cm-sec and fluences of 10 to the 10th power, 10 to the 11th power, 10 to the 12th power and 3 X 10 to the 12th power P/sq cm. I-V curves of the cells were made at room temperature, 65 C and 165 C after each irradiation. A value of 139.5 mw/sq cm was taken as AMO incident energy rate per unit area. Degradation occurred for both uncovered 1 ohm-cm and 10 ohm-cm cells. Efficiencies are generally higher than those of comparable U.S. cells tested earlier. Damage (loss in maximum power efficiency) with proton fluence is somewhat higher for 10 ohm-cm cells, measured at the three temperatures, for fluences above 2 X 10 to the 11th power P/sq cm. Cell efficiency, as expected, changes drastically with temperature.

  5. The influence of vegetation covers on soil moisture dynamics at high temporal resolution in scattered tree woodlands of Mediterranean climate

    NASA Astrophysics Data System (ADS)

    Lozano-Parra, Javier; Schnabel, Susanne; Ceballos-Barbancho, Antonio

    2015-04-01

    Soil water is a key factor that controls the organization and functioning of dryland ecosystems. However, in spite of its great importance in ecohydrological processes, most of the studies focus on daily or longer timescales, while its dynamics at shorter timescales are very little known. The main objective of this work was to determine the role of vegetation covers (grassland and tree canopy) in the soil hydrological response using measurements with high temporal resolution in evergreen oak woodland with Mediterranean climate. For this, soil water content was monitored continuously with a temporal resolution of 30 minutes and by means of capacitance sensors, mainly for the hydrological years 2010-2011 and 2011-2012. They were installed at 5, 10 and 15 cm, and 5 cm above the bedrock and depending on soil profile. This distribution along the soil profile is justified because soils are generally very shallow and most of the roots are concentrated in the upper layer. The sensors were gathered in 8 soil moisture stations in two contrasting situations characterized by different vegetation covers: under tree canopy and in open spaces or grasslands. Soil moisture variations were calculated at rainfall event scale at top soil layer and deepest depth by the difference between the final and initial soil moisture registered by a sensor at the finish and the beginning of the rainfall event, respectively. Besides, as soil moisture changes are strongly influenced by antecedent conditions, different antecedent soil moisture conditions or states, from driest to wettest, were also defined. The works were carried out in 3 experimental farms of the Spanish region of Extremadura. Results obtained revealed that rainwater amount bypassing vegetation covers and reaching the soil may temporarily be modified by covers according to precipitation properties and antecedent environmental conditions (from dry to wet) before the rain episode. Rainfall amounts triggering a positive soil

  6. Leaching of indaziflam applied at two rates under different rainfall situations in Florida Candler soil.

    PubMed

    Jhala, Amit J; Ramirez, Analiza H M; Singh, Megh

    2012-03-01

    Indaziflam {N-[(1R, 2S)-2,3-dihydro-2,6-dimethyl-1H-inden-1-yl]-6-[(1RS)-1fluoroethyl]-1,3,5-triazine-2,4-diamine} is a new pre-emergence herbicide recently registered for a broad spectrum weed control in Florida citrus. Experiments were conducted to evaluate leaching of indaziflam applied at 73 and 145 g ai ha(-1) in Florida Candler soil under simulated rainfall of 5, 10, and 15 cm ha(-1). Indaziflam leached the least (12.6 ± 0.6 cm) when applied at 73 g ai ha(-1) under 5 cm ha(-1) rainfall. Indaziflam leached furthest (30.2 ± 0.9 cm) when applied at 145 g ai ha(-1) under 15 cm ha(-1) rainfall. The visual control ratings of a bio-indicator species ryegrass (Lolium multiflorum L.) was 97% at 15 cm ha(-1) rainfall when indaziflam applied at 145 g ai ha(-1) in the 26 to 30 cm horizon indicating the maximum movement and activity of indaziflam. A dose response experiment was conducted to determine the sensitivity of ryegrass to various doses of indaziflam that confirmed that application of indaziflam at 29.20 g ai ha(-1) was sufficient to prevent germination of ryegrass. There was no mortality of ryegrass plants beyond the 30 cm and the biomass of ryegrass was comparable with untreated control indicating that indaziflam did not leach beyond this distance even under 15 cm ha(-1) rainfall.

  7. Evidence for Extended (5-10 Ma) Emplacement of Ferrar Dolerite from 40Ar-39Ar Geochronology

    NASA Astrophysics Data System (ADS)

    Knight, K. B.; Renne, P. R.

    2005-12-01

    Antarctica's Ferrar large igneous province (LIP) is dominated by dolerites linked in time, space and geochemical character with the nearby Kirkpatrick basalts, and more broadly, with magmas preserved in Dronning Maud Land (Antarctica), the Karoo LIP (southern Africa) and the Chon Aike LIP (Patagonia). Together, these magmatic bodies represent an estimated emplacement volume of ~3 x 106 km3, correlated with the break-up and post-break-up activity of the Gondwana supercontinent in the middle Jurassic. Plagioclase separates from 9 Ferrar dolerites exposed across the Dry Valleys of the Transantarctic Mountains were analyzed using the 40Ar-39Ar method. Detailed apparent age spectra reveal a range of well-defined plateau ages. Four samples yield indistinguishable ages with a weighted mean age 180.0 ± 0.5 Ma. The remaining 5 samples yield statistically distinct and significantly younger plateau ages, decreasing to as young as ca. 173 Ma. These ages may represent emplacement and/or cooling ages (below ~300°C, the approximate closure temperature for argon in plagioclase). Spectacular exposure and preservation of the Ferrar intrusive complex has led to increased interest in development of models of magma mush formation and emplacement. These data provide quantitative constraints for models of magma emplacement for the Ferrar, suggesting either the presence of long-lived magma chambers or sufficient thermal insulation or input to allow heterogeneous slow cooling of the Ferrar dolerites. The suggestion of protracted (5-10 Ma) intrusive activity supports previous geochronology data reported from Dronning Maud Land and the Ferrar, as well as the broad temporal picture arising around the time of Gondwana break-up.

  8. [Pharmacological effects of CM6912 and its main metabolites].

    PubMed

    Morishita, H; Kushiku, K; Furukawa, T; Yamaki, Y; Izawa, M; Shibazaki, Y; Shibata, U

    1985-07-01

    Pharmacodynamic effects of ethyl 7-chloro-2,3-dihydro-5-(2-fluorophenyl)-2-oxo-1H-1,4- benzodiazepine-3-carboxylate (CM6912), a new benzodiazepine derivative, and its main metabolites (CM6913 = M1, CM7116 = M2) on the peripheral systems were investigated in several species of animals. In pentobarbital-anesthetized rabbits, CM6912 and M2 (1 or 5 mg/kg, i.v.) had little effect on blood pressure, heart rate and ECG, but it slightly reduced the respiration rate. M1 decreased the heart rate without affecting respiration, blood pressure and ECG. In conscious rabbits, CM6912 and M2 (1 mg/kg, i.v.) did not affect respiration, blood pressure, heart rate and ECG, but M1 (1 mg/kg, i.v.) increased the heart rate. CM6912 (5 or 30 mg/kg), when administered orally, also increased heart rate. In pentobarbital-anesthetized dogs, CM6912 and its metabolites (5 mg/kg, i.v.) decreased respiration and heart rate without affecting blood pressure and ECG. CM 6912 (5 mg/kg, i.v.) did not affect cardiovascular responses to the carotid occlusion, vagus stimulation, and pre- and post-ganglionic stimulation of cardiac ganglion in anesthetized dogs. CM6912 and its metabolites affected neither the spontaneous contraction nor the heart rate of isolated rabbit atria. These compounds also had no action on isolated aortic strips from rabbits. CM6912 and its metabolites did not affect the muscle tone of isolated guinea pig intestine, and it had no effects on the contractile responses to acetylcholine, histamine, serotonin and barium chloride. In isolated rabbit intestine, CM6912 and M2 slightly reduced the amplitude of contraction, while M1 had no effect. CM6912 and its metabolites did not affect the spontaneous motility of isolated non-pregnant and pregnant rat uteri as well as in situ non-pregnant rat uterus and isolated guinea pig vas deferens, including the contractile response to adrenaline. CM6912 and M2 relaxed isolated guinea pig trachea strips only at high concentrations. CM6912 and its

  9. Changes in Physical and Chemical Soil Properties on Burnt Shrub Areas in Mediterranean Mountains, Northern Portugal

    NASA Astrophysics Data System (ADS)

    Fonseca, Felícia; de Figueiredo, Tomás; Leite, Micaela

    2014-05-01

    Human induced fire in scrublands to obtain better pastures for cattle is a relatively common practice in North Portugal. During burning, plant cover and litter layers are consumed, and the mineral soil is heated, resulting in changes to physical, chemical, mineralogical, and biological soil properties. Aiming at evaluating the effect of this kind of fires on a set of physical and chemical soil properties, two study areas were selected in contrasting mountain environments: Edroso, Vinhais municipality, NE Portugal, with typical Mediterranean climate, and Revelhe, Fafe, NW Portugal, with a strong ocean-influenced climate. In both, sampling was carried out in contiguous areas burnt and not burnt, covered by shrub vegetation, predominantly Cytisus multiflorus and Ulex europeus. In each study area (Edroso and Revelhe) 16 locations were selected for soil sampling (8 in the burned area and 8 in the not burnt area), six months after fire occurrence. Disturbed soil samples were collected in the layers 0-5, 5-10, 10-15, 15-20 and 20-30 cm depth, for assessing organic matter, N, P and K concentration, cation exchange capacity and related determinations, soil pH, electrical conductivity and soil texture. Undisturbed samples were collected, in 100 cm3 cylinders, to determine bulk density in the same above mentioned layers, and permeability in the 0-5 cm layer. Compared results of burnt and not burnt areas in Edroso and Revelhe study sites, show that coarse elements content and permeability decreased and bulk density slightly increased with the fire effect. Chemical properties in both sites changed with after fire, as organic matter content, exchangeable Al and cation exchange capacity increased, the opposite trend being found for phosphorus, sum of exchangeable bases and electrical conductivity. Potassium, total nitrogen and exchangeable acidity showed different soil responses to fire in the two study areas. Results stress the clear effects of fire on fertility related soil

  10. Soil Phosphorus Stoichiometry Drives Carbon Turnover Along a Soil C Gradient Spanning Mineral and Organic Soils Under Rice Cultivation

    NASA Astrophysics Data System (ADS)

    Hartman, W.; Ye, R.; Horwath, W. R.; Tringe, S. G.

    2014-12-01

    Soil carbon (C) cycling is linked to the availability of nutrients like nitrogen (N) and phosphorus (P). However, the role of soil P in influencing soil C turnover and accumulation is poorly understood, with most models focusing on C:N ratios based on the assumption that terrestrial ecosystems are N limited. To determine the effects of N and P availability on soil C turnover, we compared soil respiration over the course of a growing season in four adjacent rice fields with 5%, 10%, 20% and 25% soil C. In each of these fields, plots were established to test the effect of N additions on plant growth, using control and N addition treatments (80 kg N/ha urea). Although soil P was not manipulated in parallel, prior work has shown soil P concentrations decline markedly with increasing soil C content. Soil CO2 flux was monitored using static chambers at biweekly intervals during the growing season, along with porewater dissolved organic C and ammonium. Soils were collected at the end of the growing season, and tested for total C, N, and P, extractable N and P, pH, base cations and trace metals. Soil DNA was also extracted for 16S rRNA sequencing to profile microbial communities. Soil N additions significantly increased CO2 flux and soil C turnover (seasonal CO2 flux per unit soil C) in 5% and 10% C fields, but not in 20% or 25% C fields. Soil C content was closely related to soil N:P stoichiometry, with N:P ratios of ca. 12, 16, 24, and 56 respectively in the 5, 10, 20 and 25% C fields. Seasonal CO2 fluxes (per m2) were highest in 10% C soils. However, soil C turnover was inversely related to soil C concentrations, with the greatest C turnover at the lowest values of soil C. Soil C turnover showed stronger relationships with soil chemical parameters than seasonal CO2 fluxes alone, and the best predictors of soil C turnover were soil total and extractable N:P ratios, along with extractable P alone. Our results show that soil P availability and stoichiometry influence the

  11. [Community traits of soil fauna in forestlands converted from cultivated lands in limestone red soil region of Ruichang, Jiangxi Province of China].

    PubMed

    Li, Tao; Liu, Yuan-Qiug; Guo, Sheng-Mao; Ke, Guo-Qing; Zhang, Zhao; Xiao, Xu-Bao; Liu, Wu

    2012-04-01

    This paper studied the variations of the community composition and individuals' number of soil fauna in limestone red soil region of Ruichang, Jiangxi Province after six years of converting cultivated lands into forestlands. Three converted forestlands, including the lands of mixed multiple-species forest, bamboo-broadleaved forest, and tree-seedling integration, were selected as test objects, with cultivated lands as the comparison. A total of 34 orders, 17 classes, and 6 phyla of soil fauna were observed in the converted forestlands. The dominant group was Nematoda, accounting for 86.7% of the total, whereas Acarina, Enchytraeidae, and Collembola were the common groups. In the cultivated lands, soil fauna had 21 orders, 10 classes, and 5 phyla. The dominant group was also Nematoda, accounting 86.7% of the total, and Acarina and Enchytraeidae were the common groups. In the converted forestlands, the group number of rare species was greater than that in the cultivated lands (30 vs. 18), and, except in winter, the group number and average density were significantly higher than those in the cultivated lands (P < 0.05). The vertical distribution of soil fauna in the soil profiles showed an obvious surface accumulation, which was more apparent in converted forestlands than in cultivated lands, and the individuals' number had significant differences between the surface (0-5 cm) layer and the 5-10 cm and 10-15 cm layers (P < 0.01) for both the converted forestlands and the cultivated lands. The group number of soil fauna in the converted forestlands had a seasonal variation ranked in the order of summer > autumn > spring > winter, and there was a significant difference between summer-autumn and spring-winter. The average density of the soil fauna also had a seasonal variation but ranked as autumn > summer > spring > winter, and the differences among the seasons were significant (P < 0.05). The biodiversity index of soil fauna was significantly higher in converted

  12. Evaluation of CM5 Charges for Condensed-Phase Modeling.

    PubMed

    Vilseck, Jonah Z; Tirado-Rives, Julian; Jorgensen, William L

    2014-07-01

    The recently developed Charge Model 5 (CM5) is tested for its utility in condensed-phase simulations. The CM5 approach, which derives partial atomic charges from Hirshfeld population analyses, provides excellent results for gas-phase dipole moments and is applicable to all elements of the periodic table. Herein, the adequacy of scaled CM5 charges for use in modeling aqueous solutions has been evaluated by computing free energies of hydration (ΔG hyd) for 42 neutral organic molecules via Monte Carlo statistical mechanics. An optimal scaling factor for the CM5 charges was determined to be 1.27, resulting in a mean unsigned error (MUE) of 1.1 kcal/mol for the free energies of hydration. Testing for an additional 20 molecules gave an MUE of 1.3 kcal/mol. The high precision of the results is confirmed by free energy calculations using both sequential perturbations and complete molecular annihilation. Performance for specific functional groups is discussed; sulfur-containing molecules yield the largest errors. In addition, the scaling factor of 1.27 is shown to be appropriate for CM5 charges derived from a variety of density functional methods and basis sets. Though the average errors from the 1.27*CM5 results are only slightly lower than those using 1.14*CM1A charges, the broader applicability and easier access to CM5 charges via the Gaussian program are additional attractive features. The 1.27*CM5 charge model can be used for an enormous variety of applications in conjunction with many fixed-charge force fields and molecular modeling programs. PMID:25061445

  13. Managing compost stability and amendment to soil to enhance soil heating during soil solarization.

    PubMed

    Simmons, Christopher W; Guo, Hongyun; Claypool, Joshua T; Marshall, Megan N; Perano, Kristen M; Stapleton, James J; Vandergheynst, Jean S

    2013-05-01

    Soil solarization is a method of soil heating used to eradicate plant pathogens and weeds that involves passive solar heating of moist soil mulched (covered) with clear plastic tarp. Various types of organic matter may be incorporated into soil prior to solarization to increase biocidal activity of the treatment process. Microbial activity associated with the decomposition of soil organic matter may increase temperatures during solarization, potentially enhancing solarization efficacy. However, the level of organic matter decomposition (stability) necessary for increasing soil temperature is not well characterized, nor is it known if various amendments render the soil phytotoxic to crops following solarization. Laboratory studies and a field trial were performed to determine heat generation in soil amended with compost during solarization. Respiration was measured in amended soil samples prior to and following solarization as a function of soil depth. Additionally, phytotoxicity was estimated through measurement of germination and early growth of lettuce seedlings in greenhouse assays. Amendment of soil with 10%(g/g) compost containing 16.9 mg CO2/gdry weight organic carbon resulted in soil temperatures that were 2-4 °C higher than soil alone. Approximately 85% of total organic carbon within the amended soil was exhausted during 22 days of solarization. There was no significant difference in residual respiration with soil depth down to 17.4 cm. Although freshly amended soil proved highly inhibitory to lettuce seed germination and seedling growth, phytotoxicity was not detected in solarized amended soil after 22 days of field solarization.

  14. Managing compost stability and amendment to soil to enhance soil heating during soil solarization.

    PubMed

    Simmons, Christopher W; Guo, Hongyun; Claypool, Joshua T; Marshall, Megan N; Perano, Kristen M; Stapleton, James J; Vandergheynst, Jean S

    2013-05-01

    Soil solarization is a method of soil heating used to eradicate plant pathogens and weeds that involves passive solar heating of moist soil mulched (covered) with clear plastic tarp. Various types of organic matter may be incorporated into soil prior to solarization to increase biocidal activity of the treatment process. Microbial activity associated with the decomposition of soil organic matter may increase temperatures during solarization, potentially enhancing solarization efficacy. However, the level of organic matter decomposition (stability) necessary for increasing soil temperature is not well characterized, nor is it known if various amendments render the soil phytotoxic to crops following solarization. Laboratory studies and a field trial were performed to determine heat generation in soil amended with compost during solarization. Respiration was measured in amended soil samples prior to and following solarization as a function of soil depth. Additionally, phytotoxicity was estimated through measurement of germination and early growth of lettuce seedlings in greenhouse assays. Amendment of soil with 10%(g/g) compost containing 16.9 mg CO2/gdry weight organic carbon resulted in soil temperatures that were 2-4 °C higher than soil alone. Approximately 85% of total organic carbon within the amended soil was exhausted during 22 days of solarization. There was no significant difference in residual respiration with soil depth down to 17.4 cm. Although freshly amended soil proved highly inhibitory to lettuce seed germination and seedling growth, phytotoxicity was not detected in solarized amended soil after 22 days of field solarization. PMID:23422041

  15. Ion accelerator systems for high power 30 cm thruster operation

    NASA Technical Reports Server (NTRS)

    Aston, G.

    1982-01-01

    Two and three-grid accelerator systems for high power ion thruster operation were investigated. Two-grid translation tests show that over compensation of the 30 cm thruster SHAG grid set spacing the 30 cm thruster radial plasma density variation and by incorporating grid compensation only sufficient to maintain grid hole axial alignment, it is shown that beam current gains as large as 50% can be realized. Three-grid translation tests performed with a simulated 30 cm thruster discharge chamber show that substantial beamlet steering can be reliably affected by decelerator grid translation only, at net-to-total voltage ratios as low as 0.05.

  16. Eight-cm mercury ion thruster system technology

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The technology status of 8 cm diameter electron bombardment ion thrusters is presented. Much of the technology resulting from the 5 cm diameter thruster has been adapted and improved upon to increase the reliability, durability, and efficiency of the 8 cm thruster. Technology discussed includes: dependence of neutralizer tip erosion upon neutralizer flow rate; impregnated and rolled-foil insert cathode performance and life testing; neutralizer position studies; thruster ion beam profile measurements; high voltage pulse ignition; high utilization ion machined accelerator grids; deposition internal and external to the thruster; thruster vectoring systems; thruster cycling life testing and thruster system weights for typical mission applications.

  17. Biogeosystem technique as the way to certainty of soil, hydrosphere, environment and climate

    NASA Astrophysics Data System (ADS)

    Kalinitchenko, Valery; Batukaev, Abdulmalik; Zarmaev, Ali; Startsev, Viktor; Chernenko, Vladimir; Dikaev, Zaurbek; Sushkova, Svetlana

    2016-04-01

    The modern technological platform awkwardly imitates the Nature. Teaching the Geosciences, development of technology, overcoming the problem of uncertainty of geospheres is impossible on the base of outdated knowledge. An emphasis is to be done not on the natural analogues, but on our new technologies - Biogeosystem Technique (BGT*). BGT* is a transcendental (not imitating the natural processes) approach to soil processing, regulation of fluxes of energy, gas, water, matter and biological productivity of biosphere: Intrasoil milling processing in 20-50 cm soil layer provides new soil disperse system, best conditions for stable evolution of techno-soil and plant growth in period up to 40 years after the single processing. Pulse intrasoil discrete irrigation provides an injection of small discrete dose of water which distributes in vertical soil cylinder. Lateral distance between successive injections is 10-15 cm. The water within 5-10 min after injection spreads in cylinder of diameter 2-4 cm at depth from 5 to 50 cm. The soil carcass around the cylinder is dry and mechanically stable. Mean thermodynamic soil water potential after watering is of -0.2 MPa. Stomatal apparatus is in a regulation mode, transpiration rate is reduced, soil solution concentration increased, plant nutrition rate and biological productivity are high. No excessive plant transpiration, evaporation and seepage of water from soil. Intrasoil environmentally safe waste return during intrasoil milling processing and (or) intrasoil pulse discrete plants watering with nutrition. Is provided the medically, veterinary and environmentally safe recycle of municipal, industrial, biological and agricultural wastes into the soil continuum. All applied substances transform to plant nutrients, not degrade to the greenhouse gas, or become the deposit of waste. Capabilities of intrasoil technologies of BGT* to correct and sustain the Nature: Correct soil evolution, long-term biological productivity of intrasoil

  18. Contribution of root respiration to soil surface CO2 flux in a boreal black spruce chronosequence.

    PubMed

    Bond-Lamberty, Ben; Wang, Chuankuan; Gower, Stith T

    2004-12-01

    We quantified the contributions of root respiration (RC) and heterotrophic respiration to soil surface CO2 flux (RS) by comparing trenched and untrenched plots in well-drained and poorly drained stands of a black spruce (Picea mariana (Mill.) BSP) fire chronosequence in northern Manitoba, Canada. Our objectives were to: (1) test different equations for modeling RS as a function of soil temperature; and (2) model annual RS and RC for the chronosequence from continuous soil temperature measurements. The choice of equation to model RS strongly affected annual RS and RC, with an Arrhenius-based model giving the best fit to the data, especially at low temperatures. Modeled values of annual RS were positively correlated with soil temperature at 2-cm depth and were affected by year of burn and trenching, but not by soil drainage. During the growing season, measured RC was low in May, peaked in late July and declined to low values by the end of the growing season. Annual RC was < 5% of RS in the recently burned stands, approximately 40% in the 21-year-old stands and 5-15% in the oldest (152-year-old) stands. Evidence suggests that RC may have been underestimated in the oldest stands, with residual root decay from trenching accounting for 5-10% of trenched plot RS at most sites. PMID:15465701

  19. CM Process Improvement and the International Space Station Program (ISSP)

    NASA Technical Reports Server (NTRS)

    Stephenson, Ginny

    2007-01-01

    This viewgraph presentation reviews the Configuration Management (CM) process improvements planned and undertaken for the International Space Station Program (ISSP). It reviews the 2004 findings and recommendations and the progress towards their implementation.

  20. Benchmarking and performance analysis of the CM-2. [SIMD computer

    NASA Technical Reports Server (NTRS)

    Myers, David W.; Adams, George B., II

    1988-01-01

    A suite of benchmarking routines testing communication, basic arithmetic operations, and selected kernel algorithms written in LISP and PARIS was developed for the CM-2. Experiment runs are automated via a software framework that sequences individual tests, allowing for unattended overnight operation. Multiple measurements are made and treated statistically to generate well-characterized results from the noisy values given by cm:time. The results obtained provide a comparison with similar, but less extensive, testing done on a CM-1. Tests were chosen to aid the algorithmist in constructing fast, efficient, and correct code on the CM-2, as well as gain insight into what performance criteria are needed when evaluating parallel processing machines.

  1. Spectral reflectance properties of carbonaceous chondrites: 2. CM chondrites

    NASA Astrophysics Data System (ADS)

    Cloutis, E. A.; Hudon, P.; Hiroi, T.; Gaffey, M. J.; Mann, P.

    2011-11-01

    We have examined the spectral reflectance properties and available modal mineralogies of 39 CM carbonaceous chondrites to determine their range of spectral variability and to diagnose their spectral features. We have also reviewed the published literature on CM mineralogy and subclassification, surveyed the published spectral literature and added new measurements of CM chondrites and relevant end members and mineral mixtures, and measured 11 parameters and searched pair-wise for correlations between all quantities. CM spectra are characterized by overall slopes that can range from modestly blue-sloped to red-sloped, with brighter spectra being generally more red-sloped. Spectral slopes, as measured by the 2.4:0.56 μm and 2.4 μm:visible region peak reflectance ratios, range from 0.90 to 2.32, and 0.81 to 2.24, respectively, with values <1 indicating blue-sloped spectra. Matrix-enriched CM spectra can be even more blue-sloped than bulk samples, with ratios as low as 0.85. There is no apparent correlation between spectral slope and grain size for CM chondrite spectra - both fine-grained powders and chips can exhibit blue-sloped spectra. Maximum reflectance across the 0.3-2.5 μm interval ranges from 2.9% to 20.0%, and from 2.8% to 14.0% at 0.56 μm. Matrix-enriched CM spectra can be darker than bulk samples, with maximum reflectance as low as 2.1%. CM spectra exhibit nearly ubiquitous absorption bands near 0.7, 0.9, and 1.1 μm, with depths up to 12%, and, less commonly, absorption bands in other wavelength regions (e.g., 0.4-0.5, 0.65, 2.2 μm). The depths of the 0.7, 0.9, and 1.1 μm absorption features vary largely in tandem, suggesting a single cause, specifically serpentine-group phyllosilicates. The generally high Fe content, high phyllosilicate abundance relative to mafic silicates, and dual Fe valence state in CM phyllosilicates, all suggest that the phyllosilicates will exhibit strong absorption bands in the 0.7 μm region (due to Fe 3+-Fe 2+ charge

  2. Influence of Sub-Surface Irrigation on Soil Conditions and Water Irrigation Efficiency in a Cherry Orchard in a Hilly Semi-Arid Area of Northern China

    PubMed Central

    Peng, Gao; Bing, Wang; Guangcan, Zhang

    2013-01-01

    Sub-surface irrigation (SUI) is a new water-saving irrigation technology. To explore the influence of SUI on soil conditions in a cherry orchard and its water-saving efficiency, experiments were conducted from 2009 to 2010 using both SUI and flood irrigation (FLI) and different SUI quotas in hilly semi-arid area of northern China. The results demonstrated the following: 1) The bulk density of the soil under SUI was 6.8% lower than that of soil under FLI (P<0.01). The total soil porosity, capillary porosity and non-capillary porosity of soils using SUI were 11.7% (P<0.01), 8.7% (P<0.01) and 43.8% (P<0.01) higher than for soils using FLI. 2) The average soil temperatures at 0, 5, 10, 15 and 20 cm of soil depth using SUI were 1.7, 1.1, 0.7, 0.4 and 0.3°C higher than those for FLI, specifically, the differences between the surface soil layers were more significant. 3) Compared with FLI, the average water-saving efficiency of SUI was 55.6%, and SUI increased the irrigation productivity by 7.9-12.3 kg m-3 ha-1. 4) The soil moisture of different soil layers using SUI increased with increases in the irrigation quotas, and the soil moisture contents under SUI were significantly higher in the 0-20 cm layer and in the 21-50 cm layer than those under FLI (P<0.01). 5) The average yields of cherries under SUI with irrigation quotas of 80-320 m3 ha-1 were 8.7%-34.9% higher than those in soil with no irrigation (CK2). The average yields of cherries from soils using SUI were 4.5%-12.2% higher than using FLI. It is appropriate to irrigate 2-3 times with 230 m3 ha-1 per application using SUI in a year with normal rainfall. Our findings indicated that SUI could maintain the physical properties, greatly improve irrigation water use efficiency, and significantly increase fruit yields in hilly semi-arid areas of northern China. PMID:24039986

  3. CmWRKY15 Facilitates Alternaria tenuissima Infection of Chrysanthemum.

    PubMed

    Fan, Qingqing; Song, Aiping; Xin, Jingjing; Chen, Sumei; Jiang, Jiafu; Wang, Yinjie; Li, Xiran; Chen, Fadi

    2015-01-01

    Abscisic acid (ABA) has an important role in the responses of plants to pathogens due to its ability to induce stomatal closure and interact with salicylic acid (SA) and jasmonic acid (JA). WRKY transcription factors serve as antagonistic or synergistic regulators in the response of plants to a variety of pathogens. Here, we demonstrated that CmWRKY15, a group IIa WRKY family member, was not transcriptionally activated in yeast cells. Subcellular localization experiments in which onion epidermal cells were transiently transfected with CmWRKY15 indicated that CmWRKY15 localized to the nucleus in vivo. The expression of CmWRKY15 could be markedly induced by the presence of Alternaria tenuissima inoculum in chrysanthemum. Furthermore, the disease severity index (DSI) data of CmWRKY15-overexpressing plants indicated that CmWRKY15 overexpression enhanced the susceptibility of chrysanthemum to A. tenuissima infection compared to controls. To illustrate the mechanisms by which CmWRKY15 regulates the response to A. tenuissima inoculation, the expression levels of ABA-responsive and ABA signaling genes, such as ABF4, ABI4, ABI5, MYB2, RAB18, DREB1A, DREB2A, PYL2, PP2C, RCAR1, SnRK2.2, SnRK2.3, NCED3A, NCED3B, GTG1, AKT1, AKT2, KAT1, KAT2, and KC1were compared between transgenic plants and controls. In summary, our data suggest that CmWRKY15 might facilitate A. tenuissima infection by antagonistically regulating the expression of ABA-responsive genes and genes involved in ABA signaling, either directly or indirectly. PMID:26600125

  4. New results on the ternary fission of 243Cm

    NASA Astrophysics Data System (ADS)

    Heyse, J.; Wagemans, C.; Vermote, S.; Serot, O.; Geltenbort, P.; Soldner, T.; Van Gils, J.

    2005-11-01

    Ternary fission is an important source of He and tritium gas in nuclear reactors and used fuel elements. Therefore a systematic study of the ternary fission yields for 4He and tritons (t) is being performed. In recent years the influence of the excitation energy of the fissioning nucleus on the triton emission probability (t/B) has been investigated for different Cm and Cf isotopes. In this paper we report on new results on the neutron induced fission of 243Cm.

  5. CmWRKY15 Facilitates Alternaria tenuissima Infection of Chrysanthemum

    PubMed Central

    Fan, Qingqing; Song, Aiping; Xin, Jingjing; Chen, Sumei; Jiang, Jiafu; Wang, Yinjie; Li, Xiran; Chen, Fadi

    2015-01-01

    Abscisic acid (ABA) has an important role in the responses of plants to pathogens due to its ability to induce stomatal closure and interact with salicylic acid (SA) and jasmonic acid (JA). WRKY transcription factors serve as antagonistic or synergistic regulators in the response of plants to a variety of pathogens. Here, we demonstrated that CmWRKY15, a group IIa WRKY family member, was not transcriptionally activated in yeast cells. Subcellular localization experiments in which onion epidermal cells were transiently transfected with CmWRKY15 indicated that CmWRKY15 localized to the nucleus in vivo. The expression of CmWRKY15 could be markedly induced by the presence of Alternaria tenuissima inoculum in chrysanthemum. Furthermore, the disease severity index (DSI) data of CmWRKY15-overexpressing plants indicated that CmWRKY15 overexpression enhanced the susceptibility of chrysanthemum to A. tenuissima infection compared to controls. To illustrate the mechanisms by which CmWRKY15 regulates the response to A. tenuissima inoculation, the expression levels of ABA-responsive and ABA signaling genes, such as ABF4, ABI4, ABI5, MYB2, RAB18, DREB1A, DREB2A, PYL2, PP2C, RCAR1, SnRK2.2, SnRK2.3, NCED3A, NCED3B, GTG1, AKT1, AKT2, KAT1, KAT2, and KC1were compared between transgenic plants and controls. In summary, our data suggest that CmWRKY15 might facilitate A. tenuissima infection by antagonistically regulating the expression of ABA-responsive genes and genes involved in ABA signaling, either directly or indirectly. PMID:26600125

  6. Soil carbon dynamics

    NASA Astrophysics Data System (ADS)

    Trumbore, Susan; Barbosa de Camargo, Plínio

    The amount of organic carbon (C) stored in the upper meter of mineral soils in the Amazon Basin (˜40 Pg C) represents ˜3% of the estimated global store of soil carbon. Adding surface detrital C stocks and soil carbon deeper than 1 m can as much as quadruple this estimate. The potential for Amazon soil carbon to respond to changes in land use, climate, or atmospheric composition depends on the form and dynamics of soil carbon. Much (˜30% in the top ˜10 cm but >85% in soils to 1 m depth) of the carbon in mineral soils of the Oxisols and Ultisols that are the predominant soil types in the Amazon Basin is in forms that are strongly stabilized, with mean ages of centuries to thousands of years. Measurable changes in soil C stocks that accompany land use/land cover change occur in the upper meter of soil, although the presence of deep roots in forests systems drives an active C cycle at depths >1 m. Credible estimates of the potential for changes in Amazon soil C stocks with future land use and climate change are much smaller than predictions of aboveground biomass change. Soil organic matter influences fertility and other key soil properties, and thus is important independent of its role in the global C cycle. Most work on C dynamics is limited to upland soils, and more is needed to investigate C dynamics in poorly drained soils. Work is also needed to relate cycles of C with water, N, P, and other elements.

  7. Changes in soil parameters under continuous plastic mulching in strawberry cultivation

    NASA Astrophysics Data System (ADS)

    Muñoz, Katherine; Diehl, Dörte; Scopchanova, Sirma; Schaumann, Gabriele E.

    2016-04-01

    Plastic mulching (PM) is a widely used practice in modern agriculture because they generate conditions for optimal yield rates and quality. However, information about long-term effects of PC on soil quality parameters is scarce. The aim of this study is to compare the effect of three different mulching managements on soil quality parameters. Sampling and methodology: Three different managements were studied: Organic mulching (OM), 2-years PM and 4-years PM. Soil samples were collected from irrigated fields in 0-5, 5-10 and 10-30 cm depths and analyzed for water content (WC), pH, dissolved organic carbon (DOC), total soil carbon (Ctot) and cation exchange capacity (CECeff). Results and discussion: Mulching management has an influence on soil parameters. The magnitude of the effects is influenced by the type (organic agriculture practice vs. plastic mulching practice) and duration of the mulching. PM modified the water distribution through the soil column. WC values at the root zone were in average 10% higher compared to those measured at the topsoil. Under OM, the WC was lower than under PM. The pH was mainly influenced by the duration of the managements with slightly higher values after 4 than after 2-years PM. Under PM, aqueous extracts of the topsoil (0-5 cm depth) contained in average with 8.5±1.8 mg/L higher DOC than in 10-30 cm depth with 5.6±0.5 mg/L, which may indicate a mobilization of organic components in the upper layers. After 4-years PM, Ctot values were slightly higher than after 2-years PM and after OM. Surprisingly, after 4-years PM, CECeff values were with 138 - 157 mmolc/kg almost 2-fold higher than after 2-years PM and OM which had with 74 - 102 mmolc/kg comparable CECeff values. Long-term PM resulted in changes of soil pH and slightly increased Ctot which probably enhanced the CECeff of the soil. However, further investigations of the effect of PM on stability of soil organic matter and microbial community structure are needed.

  8. Biochar increases plant available water in a sandy soil under an aerobic rice cropping system

    NASA Astrophysics Data System (ADS)

    de Melo Carvalho, M. T.; de Holanda Nunes Maia, A.; Madari, B. E.; Bastiaans, L.; van Oort, P. A. J.; Heinemann, A. B.; Soler da Silva, M. A.; Petter, F. A.; Meinke, H.

    2014-03-01

    The main objective of this study was to assess the impact of biochar rate (0, 8, 16 and 32 t ha-1) on the water retention capacity (WRC) of a sandy Dystric Plinthosol. The applied biochar was a by-product of slow pyrolysis (∼450 °C) of eucalyptus wood, milled to pass through a 2000 μm sieve that resulted in a material with an intrinsic porosity ≤10 μm and a specific surface area of ∼3.2 m2 g-1. The biochar was incorporated into the top 15 cm of the soil under an aerobic rice system. Our study focused on both the effects on WRC and rice yields at 2 and 3 years after application. Undisturbed soil samples were collected from 16 plots in two soil layers (5-10 and 15-20 cm). Soil water retention curves were modelled using a nonlinear mixed model which appropriately accounts for uncertainties inherent of spatial variability and repeated measurements taken within a specific soil sample. We found an increase in plant available water in the upper soil layer proportional to the rate of biochar, with about 0.8% for each t ha-1 of biochar amendment at 2 and 3 years after application. The impact of biochar on soil WRC was most likely related to an increase in overall porosity of the sandy soil, which was evident from an increase in saturated soil moisture and macro porosity with 0.5% and 1.6% for each t ha-1 of biochar applied, respectively. The increment in soil WRC did not translate into an increase in rice yield, essentially because in both seasons the amount of rainfall during critical period for rice production exceeded 650 mm. The use of biochar as a soil amendment can be a worthy strategy to guarantee yield stability under water limited conditions. Our findings raise the importance of assessing the feasibility of very high application rates of biochar and the inclusion of a detailed analysis of its physical and chemical properties as part of future investigations.

  9. CM Carbonaceous Chondrite Lithologies and Their Space Exposure Ages

    NASA Technical Reports Server (NTRS)

    Zolensky, Michael; Gregory, Timothy; Takenouchi, Atsushi; Nishiizumi, Kunihiko; Trieman, Alan; Berger, Eve; Le, Loan; Fagan, Amy; Velbel, Michael; Imae, Naoya; Yamaguchi, Akira

    2015-01-01

    The CMs are the most commonly falling C chondrites, and therefore may be a major component of C-class asteroids, the targets of several current and future space missions. Previous work [1] has concluded that CM chondrites fall into at least four distinct cosmic ray space exposure (CRE) age groups (0.1 million years, 0.2 million years, 0.6 million years and greater than 2.0 million years), an unusually large number, but the meaning of these groupings is unclear. It is possible that these meteorites came from different parent bodies which broke up at different times, or instead came from the same parent body which underwent multiple break-up events, or a combination of these scenarios, or something else entirely. The objective of this study is to investigate the diversity of lithologies which make up CM chondrites, in order to determine whether the different exposure ages correspond to specific, different CM lithologies, which permit us to constrain the history of the CM parent body(ies). We have already reported significant petrographic differences among CM chondrites [2-4]. We report here our new results.

  10. CM-2 Environmental / Modal Testing of Spacehab Racks

    NASA Technical Reports Server (NTRS)

    McNelis, Mark E.; Goodnight, Thomas W.; Farkas, Michael A.

    2001-01-01

    Combined environmental/modal vibration testing has been implemented at the NASA Glenn Research Center's Structural Dynamics Laboratory. The benefits of combined vibration testing are that it facilitates test article modal characterization and vibration qualification testing. The Combustion Module-2 (CM-2) is a space experiment that launches on Shuttle mission STS 107 in the SPACEHAB Research Double Module. The CM-2 flight hardware is integrated into a SPACEHAB single and double rack. CM-2 rack level combined vibration testing was recently completed on a shaker table to characterize the structure's modal response and verify the random vibration response. Control accelerometers and limit force gauges, located between the fixture and rack interface, were used to verify the input excitation. Results of the testing were used to verify the loads and environments for flight on the Shuttle.

  11. VLA observations of Uranus at 1. 3-20 cm

    SciTech Connect

    De Pater, I.; Gulkis, S.

    1988-08-01

    Observations of Uranus, obtained with resolution 0.5-1.2 arcsec at wavelengths 1.3, 2, 6, and 20 cm using the A and B configurations of the VLA in June-July 1982, October 1983, and February 1984, are reported. The disk-averaged brightness temperatures (DABTs) are determined by model fitting, and the results are presented in extensive graphs and contour maps and characterized in detail. Findings discussed include: (1) an overall spectrum which is relatively flat above 6 cm, (2) 1.3-6-cm brightness which is concentrated nearer to the pole than to the subsolar point, and (3) small changes in DABT from 1982 to 1983/1984 (consistent with an explanation based on a pole-equator temperature gradient). 16 references.

  12. Soil water repellency of Antarctic soils (Elephant Point). First results

    NASA Astrophysics Data System (ADS)

    Pereira, Paulo; Oliva, Marc; Ruiz Fernández, Jesus

    2015-04-01

    Hydrophobicity it is a natural properties of many soils around the world. Despite the large body of research about soil water hydrophobicity (SWR) in many environments, little information it is available about Antarctic soils and their hydro-geomorphological consequences. According to our knowledge, no previous work was carried out on this environment. Soil samples were collected in the top-soil (0-5 cm) and SWR was analysed according to the water drop penetration test. The preliminary results showed that all the soils collected were hydrophilic, however further research should be carried out in order to understand if SWR changes with soil depth and if have implications on soil infiltration during the summer season.

  13. Profiling soil water content sensor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A waveguide-on-access-tube (WOAT) sensor system based on time domain reflectometry (TDR) principles was developed to sense soil water content and bulk electrical conductivity in 20-cm (8 inch) deep layers from the soil surface to depths of 3 m (10 ft) (patent No. 13/404,491 pending). A Cooperative R...

  14. Evidence for live Cm-247 in the early solar system

    NASA Technical Reports Server (NTRS)

    Tatsumoto, M.; Shimamura, T.

    1980-01-01

    Variations of the U-238/U-235 ratio in the Allende meteorite, ranging from -35% to +19% are interpreted as evidence of live Cm-247 in the early solar system. The amounts of these and other r-products in the solar system indicate values of (9000 + or - 3000) million years for the age of the Galaxy and approximately 8 million years for the time between the end of nucleosynthesis and the formation of meteoritic grains. Three possible explanations are presented for the different values of the latter time period which are indicated by the decay of products of Cm-247, Al-27, Pu-244, and I-129.

  15. WSRC Am/Cm Stabilization Program - Cylindrical Induction Melter Studies

    SciTech Connect

    Henderson, W.A.

    1999-02-17

    1.1.1 Kilogram quantities of Americium and Curium isotopes (Am/Cm) have been produced at the U.S. Department of Energy (DOE), Savannah River Site (SRS), Aiken, South Carolina. These highly radioactive isotopes have both government and commercial value and are currently stored as a nitric acid solution at the Savannah River Site. The material represents the largest source term in the F canyon at SRS. It is proposed that the Am/Cm material be vitrified to stabilize the material for long term, recoverable storage. This paper reviews the progress made during the process development phase of this program using the Cylindrical Induction Melter.

  16. Precise measurements of primordial power spectrum with 21 cm fluctuations

    SciTech Connect

    Kohri, Kazunori; Oyama, Yoshihiko; Sekiguchi, Toyokazu; Takahashi, Tomo E-mail: oyamayo@post.kek.jp E-mail: tomot@cc.saga-u.ac.jp

    2013-10-01

    We discuss the issue of how precisely we can measure the primordial power spectrum by using future observations of 21 cm fluctuations and cosmic microwave background (CMB). For this purpose, we investigate projected constraints on the quantities characterizing primordial power spectrum: the spectral index n{sub s}, its running α{sub s} and even its higher order running β{sub s}. We show that future 21 cm observations in combinations with CMB would accurately measure above mentioned observables of primordial power spectrum. We also discuss its implications to some explicit inflationary models.

  17. Evidence for live 247Cm in the early solar system

    USGS Publications Warehouse

    Tatsumoto, M.; Shimamura, T.

    1980-01-01

    Variations of the 238U/235U ratio in the Allende meteorite, ranging from -35% to + 19%, are interpreted as evidence of live 247Cm in the early Solar System. The amounts of these and other r-products in the Solar System indicate values of (9,000??3,000) Myr for the age of the Galaxy and ??? 8 Myr for the time between the end of nucleosynthesis and the formation of meteoritic grains. Three possible explanations are presented for the different values of the latter time period which are indicated by the decay products of 247Cm, 26Al, 244Pu and 129I. ?? 1980 Nature Publishing Group.

  18. Synthesis and evaluation of new antitumor 3-aminomethyl-4,11-dihydroxynaphtho[2,3-f]indole-5,10-diones.

    PubMed

    Shchekotikhin, Andrey E; Glazunova, Valeria A; Dezhenkova, Lyubov G; Luzikov, Yuri N; Buyanov, Vladimir N; Treshalina, Helena M; Lesnaya, Nina A; Romanenko, Vladimir I; Kaluzhny, Dmitry N; Balzarini, Jan; Agama, Keli; Pommier, Yves; Shtil, Alexander A; Preobrazhenskaya, Maria N

    2014-10-30

    A series of new 3-aminomethyl-4,11-dihydroxynaphtho[2,3-f]indole-5,10-diones 6-13 bearing the cyclic diamine in the position 3 of the indole ring was synthesized. The majority of new compounds demonstrated a superior cytotoxicity than doxorubicin against a panel of mammalian tumor cells with determinants of altered drug response, that is, Pgp expression or p53 inactivation. For naphtho[2,3-f]indole-5,10-diones 6-9 bearing 3-aminopyrrolidine in the side chains, the ability to bind double-stranded DNA and inhibit topoisomerases 1 and 2 mediated relaxation of supercoiled DNA were demonstrated. Only one isomer, (R)-4,11-dihydroxy-3-((pyrrolidin-3-ylamino)methyl)-1H-naphtho[2,3-f]indole-5,10-dione (7) induced the formation of specific DNA cleavage products similar to the known topoisomerase 1 inhibitors camptothecin and indenoisoquinoline MJ-III-65, suggesting a role of the structure of the side chain of 3-aminomethylnaphtho[2,3-f]indole-5,10-diones in interaction with the target. Compound 7 demonstrated an antitumor activity in mice with P388 leukemia transplants whereas its enantiomer 6 was inactive. Thus, 3-aminomethyl derivatives of 4,11-dihydroxynaphtho[2,3-f]indole-5,10-dione emerge as a new prospective chemotype for the search of antitumor agents.

  19. 3-Aminomethyl derivatives of 4,11-dihydroxynaphtho[2,3-f]indole-5,10-dione for circumvention of anticancer drug resistance.

    PubMed

    Shchekotikhin, Andrey E; Shtil, Alexander A; Luzikov, Yuri N; Bobrysheva, Tatyana V; Buyanov, Vladimir N; Preobrazhenskaya, Maria N

    2005-03-15

    A series of 3-aminomethyl derivatives of 4,11-dihydroxynaphtho[2,3-f]indole-5,10-dione was synthesized by Mannich reaction or by the transamination of 3-dimethylaminomethyl 4,11-dihydroxy- or 4,11-dimethoxynaphtho[2,3-f]indole-5,10-dione. The potency of novel derivatives was tested on a National Cancer Institute panel of 60 human tumor cell lines as well as in cells with genetically defined determinants of cytotoxic drug resistance, P-glycoprotein (Pgp) expression, and p53 inactivation. Mannich derivatives of 4,11-dihydroxynaphtho[2,3-f]indole-5,10-dione with an additional amino function in their side chain, demonstrated equal cytotoxicity against the parental K562 leukemia cells and their Pgp-positive subline, whereas the latter showed approximately 7-fold resistance to adriamycin, a Pgp transported drug. 3-(1-Piperazinyl)methyl and 3-(quinuclidin-3-yl)aminomethyl derivatives of 4,11-dihydroxynaphtho[2,3-f]indole-5,10-dione killed HCT116 colon carcinoma cells (carrying wild type p53) and their p53-null variant within the similar range of concentrations. We conclude that Mannich modification of 4,11-dihydroxynaphtho[2,3-f]indole-5,10-dione, especially when cyclic diamine (e.g., piperazine, quinuclidine) is used, confers an important feature to the resulting compounds, namely, the potency for tumor cells otherwise resistant to a variety of anticancer drugs.

  20. Characterization of field compaction using shrinkage analysis and visual soil examination

    NASA Astrophysics Data System (ADS)

    Johannes, Alice; Keller, Thomas; Weisskopf, Peter; Schulin, Rainer; Boivin, Pascal

    2016-04-01

    Visual field examination of soil structure can be very useful in extension work, because it is easy to perform, does not require equipment or lab analyses and the result is immediately available. The main limitations of visual methods are subjectivity and variation with field conditions. To provide reliable reference information, methods for objective and quantitative assessment of soil structure quality are still necessary. Soil shrinkage analysis (ShA) (Braudeau et al., 2004) provides relevant parameters for soil functions that allow precise and accurate assessment of soil compaction. To test it, we applied ShA to samples taken from a soil structure observatory (SSO) set up in 2014 on a loamy soil in Zurich, Switzerland to quantify the structural recovery of compacted agricultural soil. The objective in this presentation is to compare the ability of a visual examination method and ShA to assess soil compaction and structural recovery on the SSO field plots. Eighteen undisturbed soil samples were taken in the topsoil (5-10 cm) and 9 samples in the subsoil (30-35 cm) of compacted plots and control. Each sample went through ShA, followed by a visual examination of the sample and analysis of soil organic carbon and texture. ShA combines simultaneous shrinkage with water retention measurements and, in addition to soil properties such as bulk density, coarse and fine porosity, also provides information on hydrostructural stability and plasma and structural porosity. For visual examination the VESS method of Ball et al. (2007) was adapted to core samples previously equilibrated at -100 hPa matric potential. The samples were randomly and anonymously scored to avoid subjectivity and were equilibrated to insure comparable conditions. Compaction decreased the total specific volume, as well as air and water content at all matric potentials. Structural porosity was reduced, while plasma porosity remained unchanged. Compaction also changed the shape of the shrinkage curve: (i

  1. The influence of plant communities on postagrogenic soils in the middle taiga zone.

    NASA Astrophysics Data System (ADS)

    Churilin, Nikita; Churilina, Alexandra; Chizhikova, Natalia; Varlamov, Evgeny

    2016-04-01

    At the present time there are many abandoned postagrogenic croplands in Russia. These lands are gradually involved in natural plant succession, which has affect on the properties of the soil. Therefore, the study of these soils is one of the important trends in the Russian soil science. The aim of the study was to identify possible trends in soil changes after a long anthropogenic impact on a base of morphological, chemical and some physical properties of postagrogenic soils under different plant communities. Soils were sampled in the south of Arkhangelsk region, Ustyansky district, near Akichkin Pochinok village. Soils are formed on clay moraine of Moscow glaciation with klastolits. All soil profiles were dug on interfluve. We determined chemical composition (pH, CaCO3%, organic carbon, CEC, F2O3 (Mer-Jackson), NPK), physical characteristics (particle size distribution, bulk density of the soil) and XRD of <1μm, 1-5μm, 5-10μm fractions from soils. We selected 4 plant communities on different stages of succession: upland meadow with domination of sod grasses (Phleum pratense, Agrostis tenuis), 16 years old birch forest where dominatants are herbaceous plants such as Poa sp., Chamerion angustiflium, Agrostis tenuis, 16 years old spruce forest with no herbaceous vegetation and 70 years old bilberry spruce forest with domination of Vaccinium myrtillus and Vaccinium vitis-idaea. To study postagrogenic soils we made 4 soil profiles under these plant communities. All profiles have evidence of anthraquic horizon and they have plough pan on a depth of 20-24 cm (confirmed by bulk density). The plowed horizon is better expressed in soils under the meadow. All 4 soils are characterized by presence of Fe-Mn segregations throughout the profiles, particle size distribution heaving to the lower horizon and residual albic horizon. We identified following soils: Albic Dystric Retisol (Cutanic Abrubptic Loamic) under the old spruce, Dystric Retisol (Cutanic Loamic Anthraquic) in

  2. [Soil moisture dynamics of apple orchard in Loess Plateau dryland].

    PubMed

    Zhao, Gang; Fan, Ting-lu; Li, Shang-zhong; Zhang, Jian-jun; Wang, Yong; Dang, Yi; Wang, Lei

    2015-04-01

    The soil moisture of 0-500 cm soil layer in a dryland orchard at its full fruit period was measured from 2009 to 2013 to explore the soil moisture dynamics. Results indicated that soil water consumption mainly occurred in the soil layer of 0-300 cm in normal rainfall year and below the 300 cm soil layer when the annual rainfall was less than 400 mm. The soil moisture in the 200-300 cm soil layer fluctuated most and was affected by rainfall and apple consumption. Seasonal drought usually happened between April and late June, while the accumulation of soil moisture mainly occurred in the rainy season from July to mid-October to alleviate the drought effectively in next spring.

  3. The Complexity and Challenges of the ICD-9-CM to ICD-10-CM Transition in Emergency Departments

    PubMed Central

    Krive, Jacob; Patel, Mahatkumar; Gehm, Lisa; Mackey, Mark; Kulstad, Erik; Li, Jianrong ‘John’; Lussier, Yves A.; Boyd, Andrew D.

    2015-01-01

    Beginning October 2015, the Center for Medicare and Medicaid Services (CMS) will require medical providers to utilize the vastly expanded ICD-10-CM system. Despite wide availability of information and mapping tools for the next generation of the ICD classification system, some of the challenges associated with transition from ICD-9-CM to ICD-10-CM are not well understood. To quantify the challenges faced by emergency physicians, we analyzed a subset of a 2010 Illinois Medicaid database of emergency department ICD-9-CM codes, seeking to determine the accuracy of existing mapping tools in order to better prepare emergency physicians for the change to the expanded ICD-10-CM system. We found that 27% of 1,830 codes represented convoluted multidirectional mappings. We then analyzed the convoluted transitions and found 8% of total visit encounters (23% of the convoluted transitions) were clinically incorrect. The ambiguity and inaccuracy of these mappings may impact the work flow associated with the translation process and affect the potential mapping between ICD codes and CPT (Current Procedural Codes) codes, which determine physician reimbursement. PMID:25863652

  4. Microwave remote sensing of soil water content

    NASA Technical Reports Server (NTRS)

    Cihlar, J.; Ulaby, F. T.

    1975-01-01

    Microwave remote sensing of soils to determine water content was considered. A layered water balance model was developed for determining soil water content in the upper zone (top 30 cm), while soil moisture at greater depths and near the surface during the diurnal cycle was studied using experimental measurements. Soil temperature was investigated by means of a simulation model. Based on both models, moisture and temperature profiles of a hypothetical soil were generated and used to compute microwave soil parameters for a clear summer day. The results suggest that, (1) soil moisture in the upper zone can be predicted on a daily basis for 1 cm depth increments, (2) soil temperature presents no problem if surface temperature can be measured with infrared radiometers, and (3) the microwave response of a bare soil is determined primarily by the moisture at and near the surface. An algorithm is proposed for monitoring large areas which combines the water balance and microwave methods.

  5. Search for Cm-248 in the early solar system

    NASA Technical Reports Server (NTRS)

    Lavielle, B.; Marti, K.; Pellas, P.; Perron, C.

    1992-01-01

    Possible evidence for the presence of Cm-248 in the early solar system was reported from fission gas studies (Rao and Gopalan, 1973) and recently from studies of very high nuclear track densities (not less than 5 x 10 exp 8/sq cm) in the merrillite of the H4 chondrite Forest Vale (F.V.) (Pellas et al., 1987). We report here an analysis of the isotopic abundances of xenon in F.V. phosphates and results of track studies in phosphate/pyroxene contacts. The fission xenon isotopic signature clearly identifies Pu-244 as the extinct progenitor. We calculate an upper limit Cm-248/Pu-244 to be less than 0.0015 at the beginning of Xe retention in F.V. phosphates. This corresponds to an upper limit of the ratio Cm-248/U-235 of not greater than 5 x 10 exp -5 further constraining the evidence for any late addition of freshly synthesized actinide elements just prior to solar system formation. The fission track density observed after annealing the phosphates at 290C (1 hr, which essentially erases spallation recoil tracks) is also in agreement with the Pu-244 abundance inferred from fission Xe. The spallation recoil tracks produced during the 76 Ma cosmic-ray exposure account for the very high track density in merrillites.

  6. Retrofit and acceptance test of 30-cm ion thrusters

    NASA Technical Reports Server (NTRS)

    Poeschel, R. L.

    1981-01-01

    Six 30 cm mercury thrusters were modified to the J-series design and evaluated using standardized test procedures. The thruster performance meets the design objectives (lifetime objective requires verification), and documentation (drawings, etc.) for the design is completed and upgraded. The retrofit modifications are described and the test data for the modifications are presented and discussed.

  7. Preparing for ICD-10-CM in physician practices.

    PubMed

    Kuehn, Lynn

    2009-08-01

    What will change under CD-10-CM, and what must be done to prepare? This is the year for physician practices to get their ducks in a row: become informed, assess their IT and training needs, and make a plan that leads to the October 1, 2013, deadline.

  8. Calorimetric determination of kQ factors for NE 2561 and NE 2571 ionization chambers in 5 cm × 5 cm and 10 cm × 10 cm radiotherapy beams of 8 MV and 16 MV photons

    NASA Astrophysics Data System (ADS)

    Krauss, Achim; Kapsch, Ralf-Peter

    2007-10-01

    The relative uncertainty of the ionometric determination of the absorbed dose to water, Dw, in the reference dosimetry of high-energy photon beams is in the order of 1.5% and is dominated by the uncertainty of the calculated chamber- and energy-dependent correction factors kQ. In the present investigation, kQ values were determined experimentally in 5 cm × 5 cm and 10 cm × 10 cm radiotherapy beams of 8 MV and 16 MV bremsstrahlung by means of a water calorimeter operated at 4 °C. Ionization chambers of the types NE 2561 and NE 2571 were calibrated directly in the water phantom of the calorimeter. The measurements were carried out at the linear accelerator of the Physikalisch-Technische Bundesanstalt. It is shown that the kQ factor of a single ionization chamber can be measured with a standard uncertainty of less than 0.3%. No significant variations of kQ were found for the different lateral sizes of the radiation fields used in this investigation.

  9. The 21 cm signature of a cosmic string loop

    SciTech Connect

    Pagano, Michael; Brandenberger, Robert E-mail: rhb@physics.mcgill.ca

    2012-05-01

    Cosmic string loops lead to nonlinear baryon overdensities at early times, even before the time which in the standard LCDM model corresponds to the time of reionization. These overdense structures lead to signals in 21 cm redshift surveys at large redshifts. In this paper, we calculate the amplitude and shape of the string loop-induced 21 cm brightness temperature. We find that a string loop leads to a roughly elliptical region in redshift space with extra 21 cm emission. The excess brightness temperature for strings with a tension close to the current upper bound can be as high as 1deg K for string loops generated at early cosmological times (times comparable to the time of equal matter and radiation) and observed at a redshift of z+1 = 30. The angular extent of these predicted 'bright spots' is x{sup '}. These signals should be detectable in upcoming high redshift 21 cm surveys. We also discuss the application of our results to global monopoles and primordial black holes.

  10. Adaptation of California Measure of Mental Motivation-CM3

    ERIC Educational Resources Information Center

    Özdemir, Hasan Fehmi; Demirtasli, Nükhet Çikrikçi

    2015-01-01

    Education without doubt, plays a vital role for individuals to gain the essential personal traits of the 21st century, also known as "knowledge age". One of the most important skills among these fundamental qualities which the individuals should be equipped with is critical thinking. California Measure of Mental Motivation-CM3 was…

  11. Maribo—A new CM fall from Denmark

    NASA Astrophysics Data System (ADS)

    Haack, Henning; Grau, Thomas; Bischoff, Addi; Horstmann, Marian; Wasson, John; Sørensen, Anton; Laubenstein, Matthias; Ott, Ulrich; Palme, Herbert; Gellissen, Marko; Greenwood, Richard C.; Pearson, Victoria K.; Franchi, Ian A.; Gabelica, Zelimir; Schmitt-Kopplin, Philippe

    2012-01-01

    Maribo is a new Danish CM chondrite, which fell on January 17, 2009, at 19:08:28 CET. The fall was observed by many eye witnesses and recorded by a surveillance camera, an all sky camera, a few seismic stations, and by meteor radar observatories in Germany. A single fragment of Maribo with a dry weight of 25.8 g was found on March 4, 2009. The coarse-grained components in Maribo include chondrules, fine-grained olivine aggregates, large isolated lithic clasts, metals, and mineral fragments (often olivine), and rare Ca,Al-rich inclusions. The components are typically rimmed by fine-grained dust mantles. The matrix includes abundant dust rimmed fragments of tochilinite with a layered, fishbone-like texture, tochilinite-cronstedtite intergrowths, sulfides, metals, and carbonates often intergrown with tochilinite. The oxygen isotopic composition: (δ17O = -1.27‰; δ18O = 4.96‰; Δ17O = -3.85‰) plots at the edge of the CM field, close to the CCAM line. The very low Δ17O and the presence of unaltered components suggest that Maribo is among the least altered CM chondrites. The bulk chemistry of Maribo is typical of CM chondrites. Trapped noble gases are similar in abundance and isotopic composition to other CM chondrites, stepwise heating data indicating the presence of gas components hosted by presolar diamond and silicon carbide. The organics in Maribo include components also seen in Murchison as well as nitrogen-rich components unique to Maribo.

  12. The impact of soil compaction and freezing-thawing cycles on soil structure and yield in Mollisol region of China

    NASA Astrophysics Data System (ADS)

    Wang, Enheng; Zhao, Yusen; Chen, Xiangwei

    2015-04-01

    Agricultural machinery tillage and alternating freezing and thawing are two critical factors associated with soil structure change and accelerates soil erosion in the black soil region of Northeast China. Combining practical machinery operation and natural freeze-thaw cycles with artificial machinery compaction in the field and artificial freeze-thaw cycles in the lab, the plus and minus benefits of machinery tillage, characterization of seasonal freeze-thaw cycles, and their effects on soil structure and yield were studied. Firstly,the effects of machinery type and antecedent water content on soil structure and soil available nutrient were investigated by measuring soil bulk density, soil strength, soil porosity, soil aggregate distribution and stability, and three soil phases. The results showed that: Machinery tillage had positive and negative influence on soil structure, soil in top cultivated layer can be loosened and ameliorated however the subsoil accumulation of compaction was resulted. For heavy and medium machinery, subsoil compaction formed in the soil depth of 41~60cm and 31~40cm, respectively; however during the soil depth of 17.5~30cm under medium machinery operation there was a new plow pan produced because of the depth difference between harvesting and subsoiling. Antecedent water content had a significant effect on soil structure under machinery operations. Higher water antecedent resulted in deeper subsoil compaction at 40cm,which was deeper by 10cm than lower water content and soil compaction accumulation occurred at the first pass under higher water content condition. Besides water content and bulk density, soil organic matter is another key factor for affecting compressive-resilient performance of tillage soil. Secondly, based on the soils sampled from fields of the black soil region, the effects of freeze-thaw cycles on soil structure at different soil depths (0 -- 40 cm, 40 -- 80 cm, 120 -- 160 cm) and size scales (field core sampling

  13. Prediction of soil organic carbon concentration and soil bulk density of mineral soils for soil organic carbon stock estimation

    NASA Astrophysics Data System (ADS)

    Putku, Elsa; Astover, Alar; Ritz, Christian

    2016-04-01

    Soil monitoring networks provide a powerful base for estimating and predicting nation's soil status in many aspects. The datasets of soil monitoring are often hierarchically structured demanding sophisticated data analyzing methods. The National Soil Monitoring of Estonia was based on a hierarchical data sampling scheme as each of the monitoring site was divided into four transects with 10 sampling points on each transect. We hypothesized that the hierarchical structure in Estonian Soil Monitoring network data requires a multi-level mixed model approach to achieve good prediction accuracy of soil properties. We used this database to predict soil bulk density and soil organic carbon concentration of mineral soils in arable land using different statistical methods: median approach, linear regression and mixed model; additionally, random forests for SOC concentration. We compared the prediction results and selected the model with the best prediction accuracy to estimate soil organic carbon stock. The mixed model approach achieved the best prediction accuracy in both soil organic carbon (RMSE 0.22%) and bulk density (RMSE 0.09 g cm-3) prediction. Other considered methods under- or overestimated higher and lower values of soil parameters. Thus, using these predictions we calculated the soil organic carbon stock of mineral arable soils and applied the model to a specific case of Tartu County in Estonia. Average estimated SOC stock of Tartu County is 54.8 t C ha-1 and total topsoil SOC stock 1.8 Tg in humus horizon.

  14. Laboratory Experiment on Electrokinetic Remediation of Soil

    ERIC Educational Resources Information Center

    Elsayed-Ali, Alya H.; Abdel-Fattah, Tarek; Elsayed-Ali, Hani E.

    2011-01-01

    Electrokinetic remediation is a method of decontaminating soil containing heavy metals and polar organic contaminants by passing a direct current through the soil. An undergraduate chemistry laboratory is described to demonstrate electrokinetic remediation of soil contaminated with copper. A 30 cm electrokinetic cell with an applied voltage of 30…

  15. An Infiltration Exercise for Introductory Soil Science

    ERIC Educational Resources Information Center

    Barbarick, K. A.; Ippolito, J. A.; Butters, G.; Sorge, G. M.

    2005-01-01

    One of the largest challenges in teaching introductory soil science is explaining the dynamics of soil infiltration. To aid students in understanding the concept and to further engage them in active learning in the soils laboratory course, we developed an exercise using Decagon Mini-Disk Infiltrometers with a tension head (h[subscript o]) of 2 cm.…

  16. Impact of long-term organic residue recycling in agriculture on soil solution composition and trace metal leaching in soils.

    PubMed

    Cambier, Philippe; Pot, Valérie; Mercier, Vincent; Michaud, Aurélia; Benoit, Pierre; Revallier, Agathe; Houot, Sabine

    2014-11-15

    Recycling composted organic residues in agriculture can reduce the need of mineral fertilizers and improve the physicochemical and biological properties of cultivated soils. However, some trace elements may accumulate in soils following repeated applications and impact other compartments of the agrosystems. This study aims at evaluating the long-term impact of such practices on the composition of soil leaching water, especially on trace metal concentrations. The field experiment QualiAgro started in 1998 on typical loess Luvisol of the Paris Basin, with a maize-wheat crop succession and five modalities: spreading of three different urban waste composts, farmyard manure (FYM), and no organic amendment (CTR). Inputs of trace metals have been close to regulatory limits, but supplies of organic matter and nitrogen overpassed common practices. Soil solutions were collected from wick lysimeters at 45 and 100 cm in one plot for each modality, during two drainage periods after the last spreading. Despite wide temporal variations, a significant effect of treatments on major solutes appears at 45 cm: DOC, Ca, K, Mg, Na, nitrate, sulphate and chloride concentrations were higher in most amended plots compared to CTR. Cu concentrations were also significantly higher in leachates of amended plots compared to CTR, whereas no clear effect emerged for Zn. The influence of amendments on solute concentrations appeared weaker at 1 m than at 45 cm, but still significant and positive for major anions and DOC. Average concentrations of Cu and Zn at 1m depth lied in the ranges [2.5; 3.8] and [2.5; 10.5 μg/L], respectively, with values slightly higher for plots amended with sewage sludge compost or FYM than for CTR. However, leaching of both metals was less than 1% of their respective inputs through organic amendments. For Cd, most values were <0.05 μg/L. So, metals added through spreading of compost or manure during 14 years may have increased metal concentrations in leachates of

  17. Impact of long-term organic residue recycling in agriculture on soil solution composition and trace metal leaching in soils.

    PubMed

    Cambier, Philippe; Pot, Valérie; Mercier, Vincent; Michaud, Aurélia; Benoit, Pierre; Revallier, Agathe; Houot, Sabine

    2014-11-15

    Recycling composted organic residues in agriculture can reduce the need of mineral fertilizers and improve the physicochemical and biological properties of cultivated soils. However, some trace elements may accumulate in soils following repeated applications and impact other compartments of the agrosystems. This study aims at evaluating the long-term impact of such practices on the composition of soil leaching water, especially on trace metal concentrations. The field experiment QualiAgro started in 1998 on typical loess Luvisol of the Paris Basin, with a maize-wheat crop succession and five modalities: spreading of three different urban waste composts, farmyard manure (FYM), and no organic amendment (CTR). Inputs of trace metals have been close to regulatory limits, but supplies of organic matter and nitrogen overpassed common practices. Soil solutions were collected from wick lysimeters at 45 and 100 cm in one plot for each modality, during two drainage periods after the last spreading. Despite wide temporal variations, a significant effect of treatments on major solutes appears at 45 cm: DOC, Ca, K, Mg, Na, nitrate, sulphate and chloride concentrations were higher in most amended plots compared to CTR. Cu concentrations were also significantly higher in leachates of amended plots compared to CTR, whereas no clear effect emerged for Zn. The influence of amendments on solute concentrations appeared weaker at 1 m than at 45 cm, but still significant and positive for major anions and DOC. Average concentrations of Cu and Zn at 1m depth lied in the ranges [2.5; 3.8] and [2.5; 10.5 μg/L], respectively, with values slightly higher for plots amended with sewage sludge compost or FYM than for CTR. However, leaching of both metals was less than 1% of their respective inputs through organic amendments. For Cd, most values were <0.05 μg/L. So, metals added through spreading of compost or manure during 14 years may have increased metal concentrations in leachates of

  18. Orion Landing Simulation Eight Soil Model Comparison

    NASA Technical Reports Server (NTRS)

    Mark, Stephen D.

    2009-01-01

    LS-DYNA finite element simulations of a rigid Orion Crew Module (CM) were used to investigate the CM impact behavior on eight different soil models. Ten different landing conditions, characterized by the combination of CM vertical and horizontal velocity, hang angle, and roll angle were simulated on the eight different soils. The CM center of gravity accelerations, pitch angle, kinetic energy, and soil contact forces were the outputs of interest. The simulation results are presented, with comparisons of the CM behavior on the different soils. The soils analyzed in this study can be roughly categorized as soft, medium, or hard, according to the CM accelerations that occur when landing on them. The soft group is comprised of the Carson Sink Wet soil and the Kennedy Space Center (KSC) Low Density Dry Sand. The medium group includes Carson Sink Dry, the KSC High Density In-Situ Moisture Sand and High Density Flooded Sand, and Cuddeback B. The hard soils are Cuddeback A and the Gantry Unwashed Sand. The softer soils were found to produce lower peak accelerations, have more stable pitch behavior, and to be less sensitive to the landing conditions. This investigation found that the Cuddeback A soil produced the highest peak accelerations and worst stability conditions, and that the best landing performance was achieved on the KSC Low Density Dry Sand.

  19. Influence of contrast morphogenetic features of urban constructed soils on the functioning of Moscow green lawn urban ecosystems: analysis based on the field model experiment

    NASA Astrophysics Data System (ADS)

    Epikhina, Anna; Vizirskaya, Mariya; Mazirov, Ilya; Vasenev, Vyacheslav; Vasenev, Ivan; Valentini, Riccardo

    2014-05-01

    sand-soil (SS)) with three version of the depths (5, 10 and 20 cm). Soil construction with 10 cm organic horizon from TS top soil was taken as a reference. Grass mixture used for the green lawn including: Lolium perenne, Poa pratensis and Festuca rubra. For all the containers we measured soil CO2 emission by Li-820, soil temperature and moisture and the grass ornamental quality based on the 30-score scale (Laptev; 1988). All the measurements have been done in June-October 2013 with two-week time steps. We also observed the dynamic in soil chemical features (Corg, Ntot and pHKCl) monthly. We found high seasonal dynamics for all the observed functioning parameters. The highest CO2 emission was obtained in the beginning of July, whereas the lowest one - at the end of August. Maximal averaged CO2 emission was shown for the TSa and TSo substrates with the 20 cm depth. The lowest flux has been fixed for the more mineralized substrat. Soil moisture was shown as the main driving factor influencing CO2 emission both for the seasonal dynamics and for the averaged values for different substrates and depths (r=0.5, p<0.05). As for the aesthetic function the highest grass ornamental quality was shown for 20 cm TS and 5 cm T substrate (30 scores), whereas the lowest one was obtained for SS substrate with 5 and 20 cm depths (5 scores). We also obtained high positive correlation between the grass ornamental quality and the CO2 emissions (r=0.84, p>0.05). This outcome highlights that the standards of urban constructed soils' optimal features should be the compromise between the beauty of the green lawn and climate mitigation demands. Supported by the RF governmental grant 11.G34.31.0079

  20. Changes of Soil Aggregate C Isotopes in No-Till Corn Following Bromegrass.

    NASA Astrophysics Data System (ADS)

    Follett, R. F.; Varvel, G.; Vogel, K. P.

    2007-12-01

    This field study is near Ithaca, Nebraska, USA (lat. 41.151, long. 96.401) on a Filbert silt loam (fine, smectitic, mesic Vertic Argialboll). The site was in bromegrass since 1986. Corn was no-till seeded into the bromegrass sod in spring 1999. A randomized complete block design with three replicates was used. No-till corn was the main treatment with nitrogen (N) as subplots. N was broadcast at the start of each growing season at 60 or 120 kg N/ha as NH4NO3. Total biomass was measured by weighing 4.4 m of row in each plot. Soil samples were obtained in May 1999 (baseline sampling), Sept 1999, June 2000, Oct 2000, Sept 2001, Nov 2002, Sept 2003, and Oct 2005 from pre-selected areas by removal of plant material from the soil surface and removing the 0-5, 5- 10, and at 4 of the 8 harvests also sampling the 10-30 cm depths with a flat-bladed shovel. Soil bulk densities were determined on clods from each layer. The moist soil was passed through an 8 mm sieve before air drying and storing. Aggregate size fractions were obtained with a Yoder wet-aggregate method. Soil size fractions obtained were > 2, 1, 0.5, 0.25, 0.125, 0.045 and < 0.045 mm. Detritus was floated to the surface and skimmed off for transfer to a separate container. Aggregates were dried at 55°C, weighed, ground, and analyzed for total C and N and 13C:12C isotope ratio. Because soil organic carbon (SOC) was labeled with the bromegrass (C3 plant) isotope signature, then during the 77 months of this experiment the re-labeling of each fraction and the total SOC with the corn (C4 plant) isotope signature and the amounts of SOC lost from aggregate size fractions with conversion of the bromegrass sod to no-till corn was measured. During 6.5 years, total SOC decreased from 21.1, 17.0, and 55.8 t/ha in the 0-5, 5-10, and 10-30 cm depths to 20.1, 16.7, and 55.5 t/ha, respectively. However the SOC in the < 2, 0.5-2, and < 0.5 mm fractions of the 0 - 5 cm depth changed from 62, 21, and 16 % of the total SOC at the

  1. The Paris meteorite, the least altered CM chondrite so far

    NASA Astrophysics Data System (ADS)

    Hewins, Roger H.; Bourot-Denise, Michèle; Zanda, Brigitte; Leroux, Hugues; Barrat, Jean-Alix; Humayun, Munir; Göpel, Christa; Greenwood, Richard C.; Franchi, Ian A.; Pont, Sylvain; Lorand, Jean-Pierre; Cournède, Cécile; Gattacceca, Jérôme; Rochette, Pierre; Kuga, Maïa; Marrocchi, Yves; Marty, Bernard

    2014-01-01

    The Paris chondrite provides an excellent opportunity to study CM chondrules and refractory inclusions in a more pristine state than currently possible from other CMs, and to investigate the earliest stages of aqueous alteration captured within a single CM bulk composition. It was found in the effects of a former colonial mining engineer and may have been an observed fall. The texture, mineralogy, petrography, magnetic properties and chemical and isotopic compositions are consistent with classification as a CM2 chondrite. There are ∼45 vol.% high-temperature components mainly Type I chondrules (with olivine mostly Fa0-2, mean Fa0.9) with granular textures because of low mesostasis abundances. Type II chondrules contain olivine Fa7 to Fa76. These are dominantly of Type IIA, but there are IIAB and IIB chondrules, II(A)B chondrules with minor highly ferroan olivine, and IIA(C) with augite as the only pyroxene. The refractory inclusions in Paris are amoeboid olivine aggregates (AOAs) and fine-grained spinel-rich Ca-Al-rich inclusions (CAIs). The CAI phases formed in the sequence hibonite, perovskite, grossite, spinel, gehlenite, anorthite, diopside/fassaite and forsterite. The most refractory phases are embedded in spinel, which also occurs as massive nodules. Refractory metal nuggets are found in many CAI and refractory platinum group element abundances (PGE) decrease following the observed condensation sequences of their host phases. Mn-Cr isotope measurements of mineral separates from Paris define a regression line with a slope of 53Mn/55Mn = (5.76 ± 0.76) × 106. If we interpret Cr isotopic systematics as dating Paris components, particularly the chondrules, the age is 4566.44 ± 0.66 Myr, which is close to the age of CAI and puts new constraints on the early evolution of the solar system. Eleven individual Paris samples define an O isotope mixing line that passes through CM2 and CO3 falls and indicates that Paris is a very fresh sample, with variation explained

  2. Peat fires as source of polycyclic aromatic hydrocarbons in soils

    NASA Astrophysics Data System (ADS)

    Tsibart, Anna

    2013-04-01

    Polycyclic aromatic hydrocarbons (PAHs) arrive from pyrogenic sources including volcanism and the combustion of oil products and plant materials. The production of PAHs during the combustion of plant materials was considered in a number of publications, but their results were mainly obtained in laboratory experiments. Insufficient data are available on the hightemperature production of PAHs in environmental objects. For example, natural fires are frequently related to the PAH sources in landscapes, but very little factual data are available on this topic. On Polistovskii reserve (Russia, Pskov region) the soil series were separated depending on the damage to the plants; these series included soils of plots subjected to fires of different intensities, as well as soils of the background plots. The series of organic and organomineral soils significantly differed in their PAH distributions. In this series, the concentration of PAHs in the upper horizons of the peat soils little varied or slightly decreased, but their accumulation occurred at a depth of 5-10 or 10-20 cm in the soils after the fires. For example, in the series of high moor soils, the content of PAHs in the upper horizons remained almost constant; significant differences were observed in the subsurface horizons: from 2 ng/g in the background soil to 70 ng/g after the fire. In the upper horizons of the oligotrophic peat soils under pine forests, the total PAH content also varied only slightly. At the same time, the content of PAHs in the soil series increased from 15 to 90 ng/g with the increasing pyrogenic damage to the plot. No clear trends of the PAH accumulation were recorded in the organomineral soils. The content of PAHs in the soddy-podzolic soil subjected to fire slightly decreased (from 20 to 10 ng/g) compared to the less damaged soil. In peat fires, the access of oxygen to the fire zone is lower than in forest fires. The oxygen deficit acts as a factor of the organic fragments recombination and

  3. No tillage effect on water retention characteristics of soil aggregates in rainfed semiarid conditions.

    NASA Astrophysics Data System (ADS)

    Blanco-Moure, Nuria; López, M. Victoria; Moret, David

    2010-05-01

    The evaluation of changes in soil moisture retention characteristics associated to alterations in soil structure is of great interest in tillage studies. Most of these studies have evaluated soil properties in samples of total soil but not in individual aggregates. However, soil behavior at a macroscale level depends on the aggregate properties. A better knowledge of aggregate characteristics, as the water retention properties, will help to explain, for example, the response of soil to tillage, compaction and crop growth, and hence, to plan adequate soil management practices. In this study we determine the water retention curve of soil aggregates of different sizes from a soil under two tillage systems (conventional and no tillage). The study was carried out in a silty clay loam soil of semiarid Aragon (NE Spain). Two tillage systems were compared: no tillage (NT) and conventional tillage with mouldboard plough (CT). Water retention curves (WRC) were determined for soil surface aggregates (0-5 cm) of three different sizes (8-4, 4-2 and 2-1 mm in diameter) by using the TDR-pressure cell (Moret et al. 2008. Soil Till. Res, 100, 114-119). The TDR-pressure cell is a non-destructive method which permits determining WRC with the only one and same soil sample. Thus, the pressure cell was filled with aggregates up to 4 cm height, weighted and wetted to saturation from the bottom. Pressure steps were sequentially applied at -0.5, -1.5, -3, -5, -10, -33, -100, -300 kPa, and water content of each aggregate sample was measured gravimetrically and by TDR 24 h after starting each pressure head step. The volume of the sample within the cell was also determined at this moment in order to obtain the bulk density and thus calculate the volumetric water content. A good relationship was obtained between the volumetric water content calculated from the gravimetric water content and the corresponding values measured by TDR (r2=0.907; p≤0.05). Within the same tillage treatment, no

  4. The impact of agriculture management on soil quality in citrus orchards in Eastern Spain

    NASA Astrophysics Data System (ADS)

    Hondebrink, Merel; Cerdà, Artemi; Cammeraat, Erik

    2015-04-01

    Currently, the agricultural management of citrus orchard in the Valencia region in E Spain, is changing from traditionally irrigated and managed orchards to drip irrigated organic managed orchards. It is not known what is the effect of such changes on soil quality and hope to shed some light with this study on this transition. It is known that the drip-irrigated orchards built in sloping terrain increase soil erosion (Cerdà et al., 2009; Li et al., 2014) and that agricultural management such as catch crops and mulches reduce sediment yield and surface runoff (Xu et al., 2012; ), as in other orchards around the world (Wang et al., 2010; Wanshnong et al., 2013; Li et al., 2014; Hazarika et al., 2014): We hypothesize that these changes have an important impact on the soil chemical and physical properties. Therefor we studied the soil quality of 12 citrus orchards, which had different land and irrigation management techniques. We compared organic (OR) and conventional (CO) land management with either drip irrigation (DRP) or flood irrigation (FLD). Soil samples at two depths, 0-1 cm and 5-10 cm, were taken for studying soil quality parameters under the different treatments. These parameters included soil chemical parameters, bulk density, texture, soil surface shear strength and soil aggregation. Half of the studied orchards were organically managed and the other 6 were conventionally managed, and for each of these 6 study sites three fields were flood irrigated plots (FLD) and the other three drip irrigated systems (DRP) In total 108 soil samples were taken as well additional irrigation water samples. We will present the results of this study with regard to the impact of the studied irrigation systems and land management systems with regard to soil quality. This knowledge might help in improving citrus orchard management with respect to maintaining or improving soil quality to ensure sustainable agricultural practices. References Cerdà, A., Giménez-Morera, A. and

  5. The 12 micron band of ethane: A spectral catalog from 765 cm(-1) to 900 cm(-1)

    NASA Technical Reports Server (NTRS)

    Atakan, A. K.; Blass, W. E.; Brault, J. W.; Daunt, S. J.; Halsey, G. W.; Jennings, D. E.; Reuter, D. C.; Susskind, J.

    1983-01-01

    The high resolution laboratory absorption spectrum of the 12 micro band of ethane gas is studied. The data were obtained using the McMath Solar Telescope 1 meter Fourier Transform interferometer at Kitt Peak National Observatory and tunable diode laser spectrometers at the University of Tennessee and NASA/Goddard Space Flight Center. Over 200 individual vibration rotation transitions were analyzed taking into account many higher order effects including torsional splitting. Line positions were reproduced to better than 0.001/cm. Both ground and upper state molecular constants were determined in the analysis. The experimental details, the analysis procedures and the results are addressed. A list of ethane transitions occurring near (14)CO2 laser lines needed for heterodyne searches for C2H6 in extraterrestrial sources is also included. A spectral catalog of the ethane nu sub g fundamental from 765/cm to 900/cm is provided. A high dispersion (1/cm 12 in.) plot of both the Kitt Peak interferometric data and a simulated spectrum with Doppler limited resolution, a table of over 8500 calculated transitions listed quantum number assignments, frequencies and intensities are provided.

  6. Remote sensing of soil moisture - Recent advances

    NASA Technical Reports Server (NTRS)

    Schmugge, T. J.

    1983-01-01

    Recent advancements in microwave remote sensing of soil moisture include a method for estimating the dependence of the soil dielectric constant on its texture, the use of a percent of field capacity to express soil moisture magnitudes independently of soil texture, methods of estimating soil moisture sampling depth, and models for describing the effect of surface roughness on microwave response in terms of surface height variance and horizontal correlation length, as well as the verification of radiative transfer model predictions of microwave emission from soils and methods for the estimation of vegetation effects on the microwave response to soil moisture. Such researches have demonstrated that it is possible to remotely sense soil moisture in the 0-5 cm soil surface layer, and simulation studies have indicated how remotely sensed surface soil moisture may be used to estimate evapotranspiration rates and root-zone soil moisture.

  7. Modeling nitrous oxide production and reduction in soil through explicit representation of denitrification enzyme kinetics.

    PubMed

    Zheng, Jianqiu; Doskey, Paul V

    2015-02-17

    An enzyme-explicit denitrification model with representations for pre- and de novo synthesized enzymes was developed to improve predictions of nitrous oxide (N2O) accumulations in soil and emissions from the surface. The metabolic model of denitrification is based on dual-substrate utilization and Monod growth kinetics. Enzyme synthesis/activation was incorporated into each sequential reduction step of denitrification to regulate dynamics of the denitrifier population and the active enzyme pool, which controlled the rate function. Parameterizations were developed from observations of the dynamics of N2O production and reduction in soil incubation experiments. The model successfully reproduced the dynamics of N2O and N2 accumulation in the incubations and revealed an important regulatory effect of denitrification enzyme kinetics on the accumulation of denitrification products. Pre-synthesized denitrification enzymes contributed 20, 13, 43, and 62% of N2O that accumulated in 48 h incubations of soil collected from depths of 0-5, 5-10, 10-15, and 15-25 cm, respectively. An enzyme activity function (E) was defined to estimate the relative concentration of active enzymes and variation in response to environmental conditions. The value of E allows for activities of pre-synthesized denitrification enzymes to be differentiated from de novo synthesized enzymes. Incorporating explicit representations of denitrification enzyme kinetics into biogeochemical models is a promising approach for accurately simulating dynamics of the production and reduction of N2O in soils.

  8. Exploring effective sampling design for monitoring soil organic carbon in degraded Tibetan grasslands.

    PubMed

    Chang, Xiaofeng; Bao, Xiaoying; Wang, Shiping; Zhu, Xiaoxue; Luo, Caiyun; Zhang, Zhenhua; Wilkes, Andreas

    2016-05-15

    The effects of climate change and human activities on grassland degradation and soil carbon stocks have become a focus of both research and policy. However, lack of research on appropriate sampling design prevents accurate assessment of soil carbon stocks and stock changes at community and regional scales. Here, we conducted an intensive survey with 1196 sampling sites over an area of 190 km(2) of degraded alpine meadow. Compared to lightly degraded meadow, soil organic carbon (SOC) stocks in moderately, heavily and extremely degraded meadow were reduced by 11.0%, 13.5% and 17.9%, respectively. Our field survey sampling design was overly intensive to estimate SOC status with a tolerable uncertainty of 10%. Power analysis showed that the optimal sampling density to achieve the desired accuracy would be 2, 3, 5 and 7 sites per 10 km(2) for lightly, moderately, heavily and extremely degraded meadows, respectively. If a subsequent paired sampling design with the optimum sample size were performed, assuming stock change rates predicted by experimental and modeling results, we estimate that about 5-10 years would be necessary to detect expected trends in SOC in the top 20 cm soil layer. Our results highlight the utility of conducting preliminary surveys to estimate the appropriate sampling density and avoid wasting resources due to over-sampling, and to estimate the sampling interval required to detect an expected sequestration rate. Future studies will be needed to evaluate spatial and temporal patterns of SOC variability.

  9. An evaluation of the performance of the soil temperature simulation algorithms used in the PRZM model.

    PubMed

    Tsiros, I X; Dimopoulos, I F

    2007-04-01

    Soil temperature simulation is an important component in environmental modeling since it is involved in several aspects of pollutant transport and fate. This paper deals with the performance of the soil temperature simulation algorithms of the well-known environmental model PRZM. Model results are compared and evaluated based on the basis of its ability to predict in situ measured soil temperature profiles in an experimental plot during a 3-year monitoring study. The evaluation of the performance is based on linear regression statistics and typical model statistical errors such as the root mean square error (RMSE) and the normalized objective function (NOF). Results show that the model required minimal calibration to match the observed response of the system. Values of the determination coefficient R(2) were found to be in all cases around the value of 0.98 indicating a very good agreement between measured and simulated data. Values of the RMSE were found to be in the range of 1.2 to 1.4 degrees C, 1.1 to 1.4 degrees C, 0.9 to 1.1 degrees C, and 0.8 to 1.1 degrees C, for the examined 2, 5, 10 and 20 cm soil depths, respectively. Sensitivity analyses were also performed to investigate the influence of various factors involved in the energy balance equation at the ground surface on the soil temperature profiles. The results showed that the model was able to represent important processes affecting the soil temperature regime such as the combined effect of the heat transfer by convection between the ground surface and the atmosphere and the latent heat flux due to soil water evaporation. PMID:17454373

  10. Development of a 60 cm Magnetic Suspension System

    NASA Astrophysics Data System (ADS)

    Sawada, Hideo; Kunimasu, Tetsuya

    A 60cm Magnetic Suspension Balance System (MSBS), which has been developed in the National Aerospace Laboratory of Japan (NAL), is described in detail. Magnetic field in the MSBS is evaluated analytically and is compared with measured one. Available magnet kinds for the MSBS are selected analytically. The optimum ratio of diameter to length of cylindrical magnet for the MSBS is also evaluated. A model position sensing and the control systems are described with calibration test results. A model holding system is also shown, which is necessary for worker’s safety at suspending a large and massive model. The control system is presented and the measured model position during suspension is examined. The balance accuracy is examined and its error of drag force can be improved by restricting the calibration test to an expected drag range. Flow of the 60cm low-speed wind tunnel equipped with the MSBS is examined to be available for wind tunnel tests.

  11. Precision measurement of cosmic magnification from 21 cm emitting galaxies

    SciTech Connect

    Zhang, Pengjie; Pen, Ue-Li; /Canadian Inst. Theor. Astrophys.

    2005-04-01

    We show how precision lensing measurements can be obtained through the lensing magnification effect in high redshift 21cm emission from galaxies. Normally, cosmic magnification measurements have been seriously complicated by galaxy clustering. With precise redshifts obtained from 21cm emission line wavelength, one can correlate galaxies at different source planes, or exclude close pairs to eliminate such contaminations. We provide forecasts for future surveys, specifically the SKA and CLAR. SKA can achieve percent precision on the dark matter power spectrum and the galaxy dark matter cross correlation power spectrum, while CLAR can measure an accurate cross correlation power spectrum. The neutral hydrogen fraction was most likely significantly higher at high redshifts, which improves the number of observed galaxies significantly, such that also CLAR can measure the dark matter lensing power spectrum. SKA can also allow precise measurement of lensing bispectrum.

  12. Lensing of 21-cm fluctuations by primordial gravitational waves.

    PubMed

    Book, Laura; Kamionkowski, Marc; Schmidt, Fabian

    2012-05-25

    Weak-gravitational-lensing distortions to the intensity pattern of 21-cm radiation from the dark ages can be decomposed geometrically into curl and curl-free components. Lensing by primordial gravitational waves induces a curl component, while the contribution from lensing by density fluctuations is strongly suppressed. Angular fluctuations in the 21-cm background extend to very small angular scales, and measurements at different frequencies probe different shells in redshift space. There is thus a huge trove of information with which to reconstruct the curl component of the lensing field, allowing tensor-to-scalar ratios conceivably as small as r~10(-9)-far smaller than those currently accessible-to be probed. PMID:23003237

  13. Intensity Mapping During Reionization: 21 cm and Cross-correlations

    NASA Astrophysics Data System (ADS)

    Aguirre, James E.; HERA Collaboration

    2016-01-01

    The first generation of 21 cm epoch of reionization (EoR) experiments are now reaching the sensitivities necessary for a detection of the power spectrum of plausible reionization models, and with the advent of next-generation capabilities (e.g. the Hydrogen Epoch of Reionization Array (HERA) and the Square Kilometer Array Phase I Low) will move beyond the power spectrum to imaging of the EoR intergalactic medium. Such datasets provide context to galaxy evolution studies for the earliest galaxies on scales of tens of Mpc, but at present wide, deep galaxy surveys are lacking, and attaining the depth to survey the bulk of galaxies responsible for reionization will be challenging even for JWST. Thus we seek useful cross-correlations with other more direct tracers of the galaxy population. I review near-term prospects for cross-correlation studies with 21 cm and CO and CII emission, as well as future far-infrared misions suchas CALISTO.

  14. POLYSHIFT Communications Software for the Connection Machine System CM-200

    DOE PAGES

    George, William; Brickner, Ralph G.; Johnsson, S. Lennart

    1994-01-01

    We describe the use and implementation of a polyshift function PSHIFT for circular shifts and end-offs shifts. Polyshift is useful in many scientific codes using regular grids, such as finite difference codes in several dimensions, and multigrid codes, molecular dynamics computations, and in lattice gauge physics computations, such as quantum chromodynamics (QCD) calculations. Our implementation of the PSHIFT function on the Connection Machine systems CM-2 and CM-200 offers a speedup of up to a factor of 3–4 compared with CSHIFT when the local data motion within a node is small. The PSHIFT routine is included in the Connection Machine Scientificmore » Software Library (CMSSL).« less

  15. 21 cm cosmology in the 21st century.

    PubMed

    Pritchard, Jonathan R; Loeb, Abraham

    2012-08-01

    Imaging the Universe during the first hundreds of millions of years remains one of the exciting challenges facing modern cosmology. Observations of the redshifted 21 cm line of atomic hydrogen offer the potential of opening a new window into this epoch. This will transform our understanding of the formation of the first stars and galaxies and of the thermal history of the Universe. A new generation of radio telescopes is being constructed for this purpose with the first results starting to trickle in. In this review, we detail the physics that governs the 21 cm signal and describe what might be learnt from upcoming observations. We also generalize our discussion to intensity mapping of other atomic and molecular lines.

  16. 21 cm cosmology in the 21st century.

    PubMed

    Pritchard, Jonathan R; Loeb, Abraham

    2012-08-01

    Imaging the Universe during the first hundreds of millions of years remains one of the exciting challenges facing modern cosmology. Observations of the redshifted 21 cm line of atomic hydrogen offer the potential of opening a new window into this epoch. This will transform our understanding of the formation of the first stars and galaxies and of the thermal history of the Universe. A new generation of radio telescopes is being constructed for this purpose with the first results starting to trickle in. In this review, we detail the physics that governs the 21 cm signal and describe what might be learnt from upcoming observations. We also generalize our discussion to intensity mapping of other atomic and molecular lines. PMID:22828208

  17. OH 18 cm TRANSITION AS A THERMOMETER FOR MOLECULAR CLOUDS

    SciTech Connect

    Ebisawa, Yuji; Inokuma, Hiroshi; Yamamoto, Satoshi; Sakai, Nami; Menten, Karl M.; Maezawa, Hiroyuki

    2015-12-10

    We have observed the four hyperfine components of the 18 cm OH transition toward the translucent cloud eastward of Heiles Cloud 2 (HCL2E), the cold dark cloud L134N, and the photodissociation region of the ρ-Ophiuchi molecular cloud with the Effelsberg 100 m telescope. We have found intensity anomalies among the hyperfine components in all three regions. In particular, an absorption feature of the 1612 MHz satellite line against the cosmic microwave background has been detected toward HCL2E and two positions of the ρ-Ophiuchi molecular cloud. On the basis of statistical equilibrium calculations, we find that the hyperfine anomalies originate from the non-LTE population of the hyperfine levels, and can be used to determine the kinetic temperature of the gas over a wide range of H{sub 2} densities (10{sup 2}–10{sup 7} cm{sup −3}). Toward the center of HCL2E, the gas kinetic temperature is determined to be 53 ± 1 K, and it increases toward the cloud peripheries (∼60 K). The ortho-to-para ratio of H{sub 2} is determined to be 3.5 ± 0.9 from the averaged spectrum for the eight positions. In L134N, a similar increase of the temperature is also seen toward the periphery. In the ρ-Ophiuchi molecular cloud, the gas kinetic temperature decreases as a function of the distance from the exciting star HD 147889. These results demonstrate a new aspect of the OH 18 cm line that can be used as a good thermometer of molecular cloud envelopes. The OH 18 cm line can be used to trace a new class of warm molecular gas surrounding a molecular cloud, which is not well traced by the emission of CO and its isotopologues.

  18. OH 18 cm Transition as a Thermometer for Molecular Clouds

    NASA Astrophysics Data System (ADS)

    Ebisawa, Yuji; Inokuma, Hiroshi; Sakai, Nami; Menten, Karl M.; Maezawa, Hiroyuki; Yamamoto, Satoshi

    2015-12-01

    We have observed the four hyperfine components of the 18 cm OH transition toward the translucent cloud eastward of Heiles Cloud 2 (HCL2E), the cold dark cloud L134N, and the photodissociation region of the ρ-Ophiuchi molecular cloud with the Effelsberg 100 m telescope. We have found intensity anomalies among the hyperfine components in all three regions. In particular, an absorption feature of the 1612 MHz satellite line against the cosmic microwave background has been detected toward HCL2E and two positions of the ρ-Ophiuchi molecular cloud. On the basis of statistical equilibrium calculations, we find that the hyperfine anomalies originate from the non-LTE population of the hyperfine levels, and can be used to determine the kinetic temperature of the gas over a wide range of H2 densities (102-107 cm-3). Toward the center of HCL2E, the gas kinetic temperature is determined to be 53 ± 1 K, and it increases toward the cloud peripheries (˜60 K). The ortho-to-para ratio of H2 is determined to be 3.5 ± 0.9 from the averaged spectrum for the eight positions. In L134N, a similar increase of the temperature is also seen toward the periphery. In the ρ-Ophiuchi molecular cloud, the gas kinetic temperature decreases as a function of the distance from the exciting star HD 147889. These results demonstrate a new aspect of the OH 18 cm line that can be used as a good thermometer of molecular cloud envelopes. The OH 18 cm line can be used to trace a new class of warm molecular gas surrounding a molecular cloud, which is not well traced by the emission of CO and its isotopologues.

  19. Control of a 30 cm diameter mercury bombardment thruster

    NASA Technical Reports Server (NTRS)

    Terdan, F. F.; Bechtel, R. T.

    1973-01-01

    Control logic functions were established for three automatic modes of operation of a 30-cm thruster using a power conditioner console with flight-like characteristics. The three modes provide: (1) automatic startup to reach thermal stability, (2) steady-state closed-loop control, and (3) the reliable recycling of the high voltages following an arc breakdown to reestablish normal operation. Power supply impedance characteristics necessary for stable operation and the effect of the magnetic baffle on the reliable recycling was studied.

  20. Semi-Lagrangian shallow water modeling on the CM-5

    SciTech Connect

    Nadiga, B.T.; Margolin, L.G.; Smolarkiewicz, P.K.

    1995-09-01

    We discuss the parallel implementation of a semi-Lagrangian shallow-water model on the massively parallel Connection Machine CM-5. The four important issues we address in this article are (i) two alternative formulations of the elliptic problem and their relative efficiencies, (ii) the performance of two successive orders of a generalized conjugate residual elliptic solver, (iii) the time spent in unstructured communication -- an unavoidable feature of semi-Lagrangian schemes, and (iv) the scalability of the algorithm.

  1. The future of primordial features with 21 cm tomography

    NASA Astrophysics Data System (ADS)

    Chen, Xingang; Meerburg, P. Daniel; Münchmeyer, Moritz

    2016-09-01

    Detecting a deviation from a featureless primordial power spectrum of fluctuations would give profound insight into the physics of the primordial Universe. Depending on their nature, primordial features can either provide direct evidence for the inflation scenario or pin down details of the inflation model. Thus far, using the cosmic microwave background (CMB) we have only been able to put stringent constraints on the amplitude of features, but no significant evidence has been found for such signals. Here we explore the limit of the experimental reach in constraining such features using 21 cm tomography at high redshift. A measurement of the 21 cm power spectrum from the Dark Ages is generally considered as the ideal experiment for early Universe physics, with potentially access to a large number of modes. We consider three different categories of theoretically motivated models: the sharp feature models, resonance models, and standard clock models. We study the improvements on bounds on features as a function of the total number of observed modes and identify parameter degeneracies. The detectability depends critically on the amplitude, frequency and scale-location of the features, as well as the angular and redshift resolution of the experiment. We quantify these effects by considering different fiducial models. Our forecast shows that a cosmic variance limited 21 cm experiment measuring fluctuations in the redshift range 30 <= z <= 100 with a 0.01-MHz bandwidth and sub-arcminute angular resolution could potentially improve bounds by several orders of magnitude for most features compared to current Planck bounds. At the same time, 21 cm tomography also opens up a unique window into features that are located on very small scales.

  2. The 21 cm signature of cosmic string wakes

    SciTech Connect

    Brandenberger, Robert H.; Danos, Rebecca J.; Hernández, Oscar F.; Holder, Gilbert P. E-mail: rjdanos@physics.mcgill.ca E-mail: holder@physics.mcgill.ca

    2010-12-01

    We discuss the signature of a cosmic string wake in 21cm redshift surveys. Since 21cm surveys probe higher redshifts than optical large-scale structure surveys, the signatures of cosmic strings are more manifest in 21cm maps than they are in optical galaxy surveys. We find that, provided the tension of the cosmic string exceeds a critical value (which depends on both the redshift when the string wake is created and the redshift of observation), a cosmic string wake will generate an emission signal with a brightness temperature which approaches a limiting value which at a redshift of z+1 = 30 is close to 400 mK in the limit of large string tension. The signal will have a specific signature in position space: the excess 21cm radiation will be confined to a wedge-shaped region whose tip corresponds to the position of the string, whose planar dimensions are set by the planar dimensions of the string wake, and whose thickness (in redshift direction) depends on the string tension. For wakes created at z{sub i}+1 = 10{sup 3}, then at a redshift of z+1 = 30 the critical value of the string tension μ is Gμ = 6 × 10{sup −7}, and it decreases linearly with redshift (for wakes created at the time of equal matter and radiation, the critical value is a factor of two lower at the same redshift). For smaller tensions, cosmic strings lead to an observable absorption signal with the same wedge geometry.

  3. Soil properties linked to Phytophthora cinnamomi presence and oak decline in Iberian dehesas

    NASA Astrophysics Data System (ADS)

    Moreno, G.; Vivas, M.; Pérez, A.; Cubera, E.; Madeira, M.; Solla, A.

    2009-04-01

    symptomatic (declined) trees, at surface, 50, 100 and 150 cm depths. Soil texture, redox potential, mineral N, and the presence of Phytophthora cinnamomi were determined. Soil bulk density was measured at the surface, and soil compactness was measured through a digital penetrometer at 0-40 cm depth. In the stream banks, fine-textured soils were significantly more common under declined trees than under healthy ones, while in slopes the contrary trend occurred. Differences were clearly observed at layers located at 100 and 150 cm depth. Soil bulk density was moderate, with mean values of 1.05 and 1.07 g cm-3 (0-5 cm depth), and 1.28 and 1.30 g cm-3 (5-10 cm) for healthy and declined oaks, respectively. Regarding soil resistance to penetration, values under declined oaks were significantly (p=0.012) higher below 20 cm depth, probably due to compaction caused by old cultivation practices. Most of the soil samples analyzed showed a high level of oxidation (superoxic and manoxic), 28% were suboxic and only 0.7% were anoxic, with a possible limitation of root growth. Although not significant, soils trended to be more reduced under declined oaks at stream banks, with a contrary tendency at slopes (Table 1). The presence of P. cinammomi in soil was positively related to oak decline in stream banks (p=0.011), but not in slopes, and associated to more compacted soils (p=0.05). The presence of P. cinammomi in roots was positively correlated with oak decay (p=0.01), being more abundant among 50-100 cm depth in slopes, and among 100-150 cm depth in the stream banks, but in both cases was mostly associated to fine-textured soils. In conclusion, Q. ilex decline was not related with anoxic conditions limiting root growth, but with soil properties leading to restricted water availability for trees in slopes, and with soil conditions favorable for P. cinnamomi root-infections in the stream banks.

  4. [Effect of Biochar Application on Soil Aggregates Distribution and Moisture Retention in Orchard Soil].

    PubMed

    An, Yan; Ji, Qiang; Zhao, Shi-xiang; Wang, Xu-dong

    2016-01-15

    Applying biochar to soil has been considered to be one of the important practices in improving soil properties and increasing carbon sequestration. In order to investigate the effects of biochar application on soil aggregates distribution and its organic matter content and soil moisture constant in different size aggregates, various particle-size fractions of soil aggregates were obtained with the dry-screening method. The results showed that, compared to the treatment without biochar (CK), the application of biochar reduced the mass content of 5-8 mm and < 0.25 mm soil aggregates at 0-10 cm soil horizon, while increased the content of 1-2 mm and 2-5 mm soil aggregates at this horizon, and the content of 1-2 mm aggregates significantly increased along with the rates of biochar application. The mean diameter of soil aggregates was reduced by biochar application at 0-10 cm soil horizon. However, the effect of biochar application on the mean diameter of soil aggregates at 10-20 cm soil horizon was not significant. Compared to CK, biochar application significantly increased soil organic carbon content in aggregates, especially in 1-2 mm aggregates which was increased by > 70% compared to CK. Both the water holding capacity and soil porosity were significantly increased by biochar application. Furthermore, the neutral biochar was more effective than alkaline biochar in increasing soil moisture. PMID:27078970

  5. [Effect of Biochar Application on Soil Aggregates Distribution and Moisture Retention in Orchard Soil].

    PubMed

    An, Yan; Ji, Qiang; Zhao, Shi-xiang; Wang, Xu-dong

    2016-01-15

    Applying biochar to soil has been considered to be one of the important practices in improving soil properties and increasing carbon sequestration. In order to investigate the effects of biochar application on soil aggregates distribution and its organic matter content and soil moisture constant in different size aggregates, various particle-size fractions of soil aggregates were obtained with the dry-screening method. The results showed that, compared to the treatment without biochar (CK), the application of biochar reduced the mass content of 5-8 mm and < 0.25 mm soil aggregates at 0-10 cm soil horizon, while increased the content of 1-2 mm and 2-5 mm soil aggregates at this horizon, and the content of 1-2 mm aggregates significantly increased along with the rates of biochar application. The mean diameter of soil aggregates was reduced by biochar application at 0-10 cm soil horizon. However, the effect of biochar application on the mean diameter of soil aggregates at 10-20 cm soil horizon was not significant. Compared to CK, biochar application significantly increased soil organic carbon content in aggregates, especially in 1-2 mm aggregates which was increased by > 70% compared to CK. Both the water holding capacity and soil porosity were significantly increased by biochar application. Furthermore, the neutral biochar was more effective than alkaline biochar in increasing soil moisture.

  6. A box corer 30 cm square and 4 m long

    NASA Astrophysics Data System (ADS)

    Foster Johnson, Richard

    1988-08-01

    To collect long, large-volume cores of diatomaceous sediment on the continental shelf off Namibia, we built a box corer that is 30 cm square and 4 m long. This paper describes the corer and the tools and procedures for sampling the covers. In terms of volume of sediment recovered in a single penetration, the corer may be among the largest ever used. The corer itself consists of a barrel with segments 20 cm long, a release mechanism at top and a thin fiberglass curtain at bottom. To support the large load of sediment without distortion, the curtain follows a semi-circular track, concave upward. During assembly and disassembly, the corer hangs vertically over the side, enabling it to operate from a relatively small ship. To sample the core, an extruding device pushes the sediment from each segment into boxes made of polyurethane foam. Ashore a specially designed jig helps slice these boxes into vertical slabs as thin as 1 cm. In the 6 days at sea that we had to test the corer and collect samples for the project, we took 9 cores, the longest of which was 3 m.

  7. Am/Cm Vitrification Process: Vitrification Material Balance Calculations

    SciTech Connect

    Smith, F.G.

    2000-08-15

    This report documents material balance calculations for the Americium/Curium vitrification process and describes the basis used to make the calculations. The material balance calculations reported here start with the solution produced by the Am/Cm pretreatment process as described in ``Material Balance Calculations for Am/Cm Pretreatment Process (U)'', SRT-AMC-99-0178 [1]. Following pretreatment, small batches of the product will be further treated with an additional oxalic acid precipitation and washing. The precipitate from each batch will then be charged to the Am/Cm melter with glass cullet and vitrified to produce the final product. The material balance calculations in this report are designed to provide projected compositions of the melter glass and off-gas streams. Except for decanted supernate collected from precipitation and precipitate washing, the flowsheet neglects side streams such as acid washes of empty tanks that would go directly to waste. Complete listings of the results of the material balance calculations are provided in the Appendices to this report.

  8. The wedge bias in reionization 21-cm power spectrum measurements

    NASA Astrophysics Data System (ADS)

    Jensen, Hannes; Majumdar, Suman; Mellema, Garrelt; Lidz, Adam; Iliev, Ilian T.; Dixon, Keri L.

    2016-02-01

    A proposed method for dealing with foreground emission in upcoming 21-cm observations from the epoch of reionization is to limit observations to an uncontaminated window in Fourier space. Foreground emission can be avoided in this way, since it is limited to a wedge-shaped region in k∥, k⊥ space. However, the power spectrum is anisotropic owing to redshift-space distortions from peculiar velocities. Consequently, the 21-cm power spectrum measured in the foreground avoidance window - which samples only a limited range of angles close to the line-of-sight direction - differs from the full redshift-space spherically averaged power spectrum which requires an average over all angles. In this paper, we calculate the magnitude of this `wedge bias' for the first time. We find that the bias amplifies the difference between the real-space and redshift-space power spectra. The bias is strongest at high redshifts, where measurements using foreground avoidance will overestimate the redshift-space power spectrum by around 100 per cent, possibly obscuring the distinctive rise and fall signature that is anticipated for the spherically averaged 21-cm power spectrum. In the later stages of reionization, the bias becomes negative, and smaller in magnitude (≲20 per cent).

  9. Distinct Distribution of Purines in CM and CR Carbonaceous Chondrites

    NASA Technical Reports Server (NTRS)

    Callahan, Michael P.; Stern, Jennifer C.; Glavin, Daniel P.; Smith, Karen E.; Martin, Mildred G.; Dworkin, Jason P.

    2010-01-01

    Carbonaceous meteorites contain a diverse suite of organic molecules and delivered pre biotic organic compounds, including purines and pyrimidines, to the early Earth (and other planetary bodies), seeding it with the ingredients likely required for the first genetic material. We have investigated the distribution of nucleobases in six different CM and CR type carbonaceous chondrites, including fivc Antarctic meteorites never before analyzed for nucleobases. We employed a traditional formic acid extraction protocol and a recently developed solid phase extraction method to isolate nucleobases. We analyzed these extracts by high performance liquid chromatography with UV absorbance detection and tandem mass spectrometry (HPLC-UV -MS/MS) targeting the five canonical RNAIDNA bases and hypoxanthine and xanthine. We detected parts-per-billion levels of nucleobases in both CM and CR meteorites. The relative abundances of the purines found in Antarctic CM and CR meteorites were clearly distinct from each other suggesting that these compounds are not terrestrial contaminants. One likely source of these purines is formation by HCN oligomerization (with other small molecules) during aqueous alteration inside the meteorite parent body. The detection of the purines adenine (A), guanine (0), hypoxanthine (HX), and xanthine (X) in carbonaceous meteorites indicates that these compounds should have been available on the early Earth prior to the origin of the first genetic material.

  10. BRIGHT SOURCE SUBTRACTION REQUIREMENTS FOR REDSHIFTED 21 cm MEASUREMENTS

    SciTech Connect

    Datta, A.; Bowman, J. D.; Carilli, C. L.

    2010-11-20

    The H I 21 cm transition line is expected to be an important probe into the cosmic dark ages and epoch of reionization. Foreground source removal is one of the principal challenges for the detection of this signal. This paper investigates the extragalactic point source contamination and how accurately bright sources ({approx}>1 Jy) must be removed in order to detect 21 cm emission with upcoming radio telescopes such as the Murchison Widefield Array. We consider the residual contamination in 21 cm maps and power spectra due to position errors in the sky model for bright sources, as well as frequency-independent calibration errors. We find that a source position accuracy of 0.1 arcsec will suffice for detection of the H I power spectrum. For calibration errors, 0.05% accuracy in antenna gain amplitude is required in order to detect the cosmic signal. Both sources of subtraction error produce residuals that are localized to small angular scales, k{sub perpendicular} {approx}> 0.05 Mpc{sup -1}, in the two-dimensional power spectrum.

  11. 21 CFR 73.3120 - 16,17-Dimethoxydinaphtho [1,2,3-cd:3′,2′,1′-lm] perylene-5,10-dione.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false 16,17-Dimethoxydinaphtho perylene-5,10-dione. 73.3120 Section 73.3120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3120...

  12. 21 CFR 73.3120 - 16,17-Dimethoxydinaphtho [1,2,3-cd:3′,2′,1′-lm] perylene-5,10-dione.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false 16,17-Dimethoxydinaphtho perylene-5,10-dione. 73.3120 Section 73.3120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3120...

  13. 21 CFR 73.3120 - 16,17-Dimethoxydinaphtho [1,2,3-cd:3′,2′,1′-lm] perylene-5,10-dione.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false 16,17-Dimethoxydinaphtho perylene-5,10-dione. 73.3120 Section 73.3120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3120...

  14. Determination of the persistence of tetracycline antibiotics and their degradates in manure-amended soil using enzyme-linked immunosorbent assay and liquid chromatography-mass spectrometry.

    PubMed

    Aga, Diana S; O'Connor, Seamus; Ensley, Steve; Payero, José O; Snow, Daniel; Tarkalson, David

    2005-09-01

    The persistence of manure-borne oxytetracycline in soil was investigated under field conditions. Soil cores were collected approximately once a month for over a period of two years and subsampled at depth increments of 0-5, 5-10, 10-15, 15-36, and 36-71 cm. Soil samples were analyzed by enzyme-linked immunosorbent assay (ELISA) and/or by liquid chromatography-mass spectrometry (LC-MS). Whereas LC-MS showed that oxytetracycline declined to <50% of its initial soil concentration after 3 weeks, ELISA showed that the total tetracyclines did not decline significantly 5 months after manure application. The differences between ELISA and LC-MS results are attributed to the broad cross-reactivity of the antibodies employed, which detect many structurally related tetracyclines, including their isomers and degradation products. Only trace amounts (< or = 1.0 microg/kg) of oxytetracycline were observed in the subsurface soil, and none was detected in water samples from field lysimeters, suggesting that oxytetracycline has low mobility in soil.

  15. Influence of macroporosity on preferential solute and colloid transport in unsaturated field soils.

    PubMed

    Cey, Edwin E; Rudolph, David L; Passmore, Joanna

    2009-06-26

    Transport of solutes and colloids in soils, particularly those subject to preferential flow along macropores, is important for assessing the vulnerability of shallow groundwater to contamination. The objective of this study was to investigate flow and transport phenomena for dissolved and colloid tracers during large infiltration events in partially saturated, macroporous soils. Controlled tracer infiltration tests were completed at two field sites in southern Ontario. A tension infiltrometer (TI) was used to infiltrate water with dissolved Brilliant Blue FCF dye simultaneously with 3.7 microm and 0.53 microm diameter fluorescent microspheres. Infiltration was conducted under maximum infiltration pressure heads ranging from -5.2 to -0.4 cm. All infiltration test sites were excavated to examine and photograph dye-stained flow patterns, map soil features, and collect samples for microsphere enumeration. Results indicated that preferential transport of dye and microspheres via macropores occurred when maximum pressure heads were greater than -3.0 cm, and the corresponding infiltration rates exceeded 2.0 cm h(-1). Dye and microspheres were detected at depths greater than 70 cm under the highest infiltration rates from both sites. Microsphere concentrations in the top 5-10 cm of soil decreased by more than two orders of magnitude relative to input concentrations, yet remained relatively constant with depth thereafter. There was some evidence for increased retention of the 3.7 microm microspheres relative to the 0.53 microm microspheres, particularly at lower infiltration pressures where straining and attachment mechanisms are most prevalent. Microspheres were observed within dye stained soil matrix surrounding individual macropores, illustrating the significance of capillary pressures in controlling the vertical migration of both tracers in the vicinity of the macropores. Overall, microsphere distributions closely followed the dye patterns, with microsphere

  16. [Effect of fertilization levels on soil microorganism amount and soil enzyme activities].

    PubMed

    Wang, Wei-Ling; Du, Jun-Bo; Xu, Fu-Li; Zhang, Xiao-Hu

    2013-11-01

    Field experiments were conducted in Shangluo pharmaceutical base in Shaanxi province to study the effect of nitrogen, phosphorus and potassium in different fertilization levels on Platycodon grandiflorum soil microorganism and activities of soil enzyme, using three-factor D-saturation optimal design with random block design. The results showed that N0P2K2, N2P2K0, N3P1K3 and N3P3K1 increased the amount of bacteria in 0-20 cm of soil compared with N0P0K0 by 144.34%, 39.25%, 37.17%, 53.58%, respectively. The amount of bacteria in 2040 cm of soil of N3P1K3 increased by 163.77%, N0P0K3 increased the amount of soil actinomycetes significantly by 192.11%, while other treatments had no significant effect. N2P0K2 and N3P1K3 increased the amounts of fungus significantly in 0-20 cm of soil compared with N0P0K0, increased by 35.27% and 92.21%, respectively. N3P0K0 increased the amounts of fungus significantly in 20-40 cm of soil by 165.35%, while other treatments had no significant effect. All treatments decrease soil catalase activity significantly in 0-20 cm of soil except for N2P0K2, and while N2P2K0 and NPK increased catalase activity significantly in 2040 cm of soil. Fertilization regime increased invertase activity significantly in 2040 cm of soil, and decreased phosphatase activity inordinately in 0-20 cm of soil, while increased phosphatase activity in 2040 cm of soil other than N1P3K3. N3P0K0, N0P0K3, N2P0K2, N2P2K0 and NPK increased soil urease activity significantly in 0-20 cm of soil compared with N0P0K0 by 18.22%, 14.87%,17.84%, 27.88%, 24.54%, respectively. Fertilization regime increased soil urease activity significantly in 2040 cm of soil other than N0P2K2. PMID:24558863

  17. A high resolution method for soil moisture mapping at large spatial and temporal scales

    NASA Astrophysics Data System (ADS)

    moreno, D.; Sayde, C.; Ochsner, T. E.; Sorin, C.; Selker, J. S.

    2013-12-01

    Soil moisture is a critical component of the planet's water budget, yet precise measurement of its dynamics across the critical scales of 0.1-1,000 m continues to be an area of great uncertainty. Here we present the preliminary results for a large scale installation of soil moisture quantification based on the work of Sayde et al. (2010) using actively heated fiber optic with a DTS system capable of soil moisture measurements at high spatial (reporting every 0.125 m) and temporal resolution (read as frequently as each 15 min)). The fiber optic (FO) sensing cables were installed in 2 sections: 1) a highly resolved multi-scale spiral 75m x 65m in size, 530 m total path length, and 2) a 770 m transect in the foot print of the cosmos cosmic ray probe installed at the site. In each of those 2 sections, the FO cables were deployed at 3 depths: 5, 10, and 15 cm. In this system the FO sensing system provides measurements of soil moisture at >39,000 locations simultaneously for each heat pulse. In addition, six soil monitoring stations along the fiber optic path were installed to provide additional validation and calibration of the DTS data. Finally, gravimetric soil moisture and soil thermal samplings were performed periodically to provide additional distributed validation and calibration of the DTS data. The ability of this DTS FO system to provide soil moisture measurements over four orders of magnitude in spatial scale (0.1 - 1,000m) will allow better understanding of the spatio-temporal variability in soil moisture in the field, which is essential to develop protocols for calibration and validation of large scale soil moisture remote sensing data (such as NASA airMOSS soil moisture air flights). The material is based upon work supported by NASA under award NNX12AP58G, with equipment and assistance also provided by CTEMPs.org with support from the National Science Foundation under Grant Number 1129003. Any opinions, findings, and conclusions or recommendations expressed

  18. Soil CO₂ dynamics in a tree island soil of the Pantanal: the role of soil water potential.

    PubMed

    Johnson, Mark S; Couto, Eduardo Guimarães; Pinto, Osvaldo B; Milesi, Juliana; Santos Amorim, Ricardo S; Messias, Indira A M; Biudes, Marcelo Sacardi

    2013-01-01

    The Pantanal is a biodiversity hotspot comprised of a mosaic of landforms that differ in vegetative assemblages and flooding dynamics. Tree islands provide refuge for terrestrial fauna during the flooding period and are particularly important to the regional ecosystem structure. Little soil CO₂ research has been conducted in this region. We evaluated soil CO₂ dynamics in relation to primary controlling environmental parameters (soil temperature and soil water). Soil respiration was computed using the gradient method using in situ infrared gas analyzers to directly measure CO₂ concentration within the soil profile. Due to the cost of the sensors and associated equipment, this study was unreplicated. Rather, we focus on the temporal relationships between soil CO₂ efflux and related environmental parameters. Soil CO₂ efflux during the study averaged 3.53 µmol CO₂ m⁻² s⁻¹, and was equivalent to an annual soil respiration of 1220 g C m⁻² y⁻¹. This efflux value, integrated over a year, is comparable to soil C stocks for 0-20 cm. Soil water potential was the measured parameter most strongly associated with soil CO₂ concentrations, with high CO₂ values observed only once soil water potential at the 10 cm depth approached zero. This relationship was exhibited across a spectrum of timescales and was found to be significant at a daily timescale across all seasons using conditional nonparametric spectral Granger causality analysis. Hydrology plays a significant role in controlling CO₂ efflux from the tree island soil, with soil CO₂ dynamics differing by wetting mechanism. During the wet-up period, direct precipitation infiltrates soil from above and results in pulses of CO₂ efflux from soil. The annual flood arrives later, and saturates soil from below. While CO₂ concentrations in soil grew very high under both wetting mechanisms, the change in soil CO₂ efflux was only significant when soils were wet from above. PMID:23762259

  19. Soil CO₂ dynamics in a tree island soil of the Pantanal: the role of soil water potential.

    PubMed

    Johnson, Mark S; Couto, Eduardo Guimarães; Pinto, Osvaldo B; Milesi, Juliana; Santos Amorim, Ricardo S; Messias, Indira A M; Biudes, Marcelo Sacardi

    2013-01-01

    The Pantanal is a biodiversity hotspot comprised of a mosaic of landforms that differ in vegetative assemblages and flooding dynamics. Tree islands provide refuge for terrestrial fauna during the flooding period and are particularly important to the regional ecosystem structure. Little soil CO₂ research has been conducted in this region. We evaluated soil CO₂ dynamics in relation to primary controlling environmental parameters (soil temperature and soil water). Soil respiration was computed using the gradient method using in situ infrared gas analyzers to directly measure CO₂ concentration within the soil profile. Due to the cost of the sensors and associated equipment, this study was unreplicated. Rather, we focus on the temporal relationships between soil CO₂ efflux and related environmental parameters. Soil CO₂ efflux during the study averaged 3.53 µmol CO₂ m⁻² s⁻¹, and was equivalent to an annual soil respiration of 1220 g C m⁻² y⁻¹. This efflux value, integrated over a year, is comparable to soil C stocks for 0-20 cm. Soil water potential was the measured parameter most strongly associated with soil CO₂ concentrations, with high CO₂ values observed only once soil water potential at the 10 cm depth approached zero. This relationship was exhibited across a spectrum of timescales and was found to be significant at a daily timescale across all seasons using conditional nonparametric spectral Granger causality analysis. Hydrology plays a significant role in controlling CO₂ efflux from the tree island soil, with soil CO₂ dynamics differing by wetting mechanism. During the wet-up period, direct precipitation infiltrates soil from above and results in pulses of CO₂ efflux from soil. The annual flood arrives later, and saturates soil from below. While CO₂ concentrations in soil grew very high under both wetting mechanisms, the change in soil CO₂ efflux was only significant when soils were wet from above.

  20. Soil CO2 Dynamics in a Tree Island Soil of the Pantanal: The Role of Soil Water Potential

    PubMed Central

    Johnson, Mark S.; Couto, Eduardo Guimarães; Pinto Jr, Osvaldo B.; Milesi, Juliana; Santos Amorim, Ricardo S.; Messias, Indira A. M.; Biudes, Marcelo Sacardi

    2013-01-01

    The Pantanal is a biodiversity hotspot comprised of a mosaic of landforms that differ in vegetative assemblages and flooding dynamics. Tree islands provide refuge for terrestrial fauna during the flooding period and are particularly important to the regional ecosystem structure. Little soil CO2 research has been conducted in this region. We evaluated soil CO2 dynamics in relation to primary controlling environmental parameters (soil temperature and soil water). Soil respiration was computed using the gradient method using in situ infrared gas analyzers to directly measure CO2 concentration within the soil profile. Due to the cost of the sensors and associated equipment, this study was unreplicated. Rather, we focus on the temporal relationships between soil CO2 efflux and related environmental parameters. Soil CO2 efflux during the study averaged 3.53 µmol CO2 m−2 s−1, and was equivalent to an annual soil respiration of 1220 g C m−2 y−1. This efflux value, integrated over a year, is comparable to soil C stocks for 0–20 cm. Soil water potential was the measured parameter most strongly associated with soil CO2 concentrations, with high CO2 values observed only once soil water potential at the 10 cm depth approached zero. This relationship was exhibited across a spectrum of timescales and was found to be significant at a daily timescale across all seasons using conditional nonparametric spectral Granger causality analysis. Hydrology plays a significant role in controlling CO2 efflux from the tree island soil, with soil CO2 dynamics differing by wetting mechanism. During the wet-up period, direct precipitation infiltrates soil from above and results in pulses of CO2 efflux from soil. The annual flood arrives later, and saturates soil from below. While CO2 concentrations in soil grew very high under both wetting mechanisms, the change in soil CO2 efflux was only significant when soils were wet from above. PMID:23762259

  1. 10 cm x 10 cm Single Gas Electron Multiplier (GEM) X-ray Fluorescence Detector for Dilute Elements

    NASA Astrophysics Data System (ADS)

    Shaban, E. H.; Siddons, D. P.; Seifu, D.

    2014-03-01

    We have built and tested a 10 cm × 10 cm single Gas Electron Multiplier (GEM) X-ray detector to probe dilute amounts of Fe in a prepared sample. The detector uses Argon/Carbon Dioxide (75/25) gas mixture flowing at a slow rate through a leak proof Plexi-glass enclosure held together by O-rings and screws. The Fluorescence X-ray emitted by the element under test is directed through a Mylar window into the drift region of the detector where abundant gas is flowing. The ionized electrons are separated, drifted into the high electric field of the GEM, and multiplied by impact ionization. The amplified negatively charged electrons are collected and further amplified by a Keithley amplifier to probe the absorption edge of the element under test using X-ray absorption spectroscopy technique. The results show that the GEM detector provided good results with less noise as compared with a Silicon drift detector (SDD).

  2. The GLOBE Soil Moisture Campaign's Light Bulb Oven

    NASA Astrophysics Data System (ADS)

    Whitaker, M. P.; Tietema, D.; Ferre, T. P.; Nijssen, B.; Washburne, J.

    2003-12-01

    The GLOBE Soil Moisture Campaign (SMC) (www.hwr.arizona.edu/globe/sci/SM/SMC) has developed a light bulb oven to provide a low budget, low-technology method for drying soil samples. Three different soils were used to compare the ability of the light bulb oven to dry soils against a standard laboratory convection oven. The soils were: 1) a very fine sandy loam (the "Gila" soil); 2) a silty clay (the "Pima" soil); and 3) a sandy soil (the "Sonoran" soil). A large batch of each soil was wetted uniformly in the laboratory. Twelve samples of each soil were placed in the light bulb oven and twelve samples were placed in the standard oven. The average gravimetric soil moisture of the Gila soil was 0.214 g/cm3 for both ovens; the average Pima soil moisture was 0.332 g/cm3 and 0.331 g/cm3 for the traditional and light bulb ovens, respectively; and the Sonoran soil moisture was 0.077 g/cm3 for both ovens. These results demonstrate that the low technology light-bulb oven was able to dry the soil samples as well as a standard laboratory oven, offering the ability to make gravimetric water content measurements when a relatively expensive drying oven is not available.

  3. [Spatial Heterogeneity of Soil Respiration in a Larch Plantation of North China at Different Sampling Scales].

    PubMed

    Yan, Jun-xia; Liang, Ya-nan; Li, Hong-jian; Li, Jun-jian

    2015-12-01

    Based on observations of soil respiration rate (Rs) and both biotic and abiotic factors in Pangquangou Nature Reserve at three sampling scales (4, 2, and 1 m), we studied the spatial heterogeneity of Rs and the factors, and analyzed impacts of soil temperature at the 5, 10 and 15 cm depth (T5, T10, T15), soil moisture over the depth of 0-10 cm (Ws), and soil total nitrogen (N), soil total organic carbon (C), ratio of carbon and nitrogen (C/N), soil total sulfur (S), litter fall mass (Lw) and litter fall moisture (Lm) on the spatial heterogeneity of Rs, respectively. We also calculated the minimum sampling number of all the factors at different confidence levels and under the responding estimation accuracy. The results showed that: (1) the spatial heterogeneity of C/N at 4 m sampling scale, Ws at 2 m sampling scale and T10, T15 at 1 m sampling scale had low variability, while the spatial variation of Rs and other related factors had medium variability. Coefficients of variation of Rs, C/N and S decreased with the increase of the sampling scales, but those of N, C, Ws, T₅, T₁₀, T₁₅, Lw and Lm showed contrary trend; (2) the spatial autocorrelation of Rs, Ws, T₅, T₁₀, T₁₅, Lw and Lm decreased with the decrease of sampling scales but the spatial autocorrelation of C, N, C/N increased with the decrease of sampling scales, and the spatial autocorrelation of S decreased with the decrease of the sampling scales at initial stage and then increased; (3) the key factors that influenced the spatial heterogeneity of soil respiration were different at different sampling scales. Soil temperature was the key factor influencing the spatial heterogeneity of Rs at a larger scale. However, at a smaller scale, the spatial heterogeneity of Rs was influenced by C, Lw and Lm; (4) the minimum sampling number for soil respiration measurement and its influencing factors reduced greatly with the decrease of confidence level and responding estimation accuracy. The sampling

  4. [Spatial Heterogeneity of Soil Respiration in a Larch Plantation of North China at Different Sampling Scales].

    PubMed

    Yan, Jun-xia; Liang, Ya-nan; Li, Hong-jian; Li, Jun-jian

    2015-12-01

    Based on observations of soil respiration rate (Rs) and both biotic and abiotic factors in Pangquangou Nature Reserve at three sampling scales (4, 2, and 1 m), we studied the spatial heterogeneity of Rs and the factors, and analyzed impacts of soil temperature at the 5, 10 and 15 cm depth (T5, T10, T15), soil moisture over the depth of 0-10 cm (Ws), and soil total nitrogen (N), soil total organic carbon (C), ratio of carbon and nitrogen (C/N), soil total sulfur (S), litter fall mass (Lw) and litter fall moisture (Lm) on the spatial heterogeneity of Rs, respectively. We also calculated the minimum sampling number of all the factors at different confidence levels and under the responding estimation accuracy. The results showed that: (1) the spatial heterogeneity of C/N at 4 m sampling scale, Ws at 2 m sampling scale and T10, T15 at 1 m sampling scale had low variability, while the spatial variation of Rs and other related factors had medium variability. Coefficients of variation of Rs, C/N and S decreased with the increase of the sampling scales, but those of N, C, Ws, T₅, T₁₀, T₁₅, Lw and Lm showed contrary trend; (2) the spatial autocorrelation of Rs, Ws, T₅, T₁₀, T₁₅, Lw and Lm decreased with the decrease of sampling scales but the spatial autocorrelation of C, N, C/N increased with the decrease of sampling scales, and the spatial autocorrelation of S decreased with the decrease of the sampling scales at initial stage and then increased; (3) the key factors that influenced the spatial heterogeneity of soil respiration were different at different sampling scales. Soil temperature was the key factor influencing the spatial heterogeneity of Rs at a larger scale. However, at a smaller scale, the spatial heterogeneity of Rs was influenced by C, Lw and Lm; (4) the minimum sampling number for soil respiration measurement and its influencing factors reduced greatly with the decrease of confidence level and responding estimation accuracy. The sampling

  5. Conversion from cropland to short rotation coppice willow and poplar: Accumulation of soil organic carbon

    NASA Astrophysics Data System (ADS)

    Georgiadis, Petros; Stupak, Inge; Vesterdal, Lars; Raulund-Rasmussen, Karsten

    2015-04-01

    Increased demand for bioenergy has intensified the production of Short Rotation Coppice (SRC) willow and poplar in temperate zones. We used a combined chronosequence and paired plot approach to study the potential of SRC willow and poplar stands to increase the soil carbon stock compared to stocks of the previous arable land-use. The study focused on well-drained soils. We sampled soil from 30 SRC stands in Denmark and southern Sweden including soils from their adjacent arable fields. The 18 willow and 12 poplar stands formed a chronosequence ranging between 4 and 29 years after conversion. The soil was sampled both with soil cores taken by fixed depths of 0-5, 5-10, 10-15, 15-25, and 25-40 cm and by genetic horizons from soil pits to 1m depth. The aim of the study was to estimate the difference and the ratio between soil carbon contents of the SRC and annual crop land and analyze the results as a chronosequence to examine the effect of age after conversion on the difference. Covariates such as soil type, fertilization type and harvest frequency were also taken into account. Preliminary results suggest an overall increase in carbon stocks over time with average accumulation rates ranging from 0.25 to 0.4 Mg ha-1 yr-1 in willow and poplar stands. Poplar stands had higher rates of C gain, probably due to less frequent harvesting. The differences in carbon between the SRC and the paired cropland were initially negative but changed to positive over time, implying loss of carbon after conversion and a later gain in soil carbon with stand age. Pairwise differences ranged from -25 Mg C ha-1 to 37 Mg C ha-1 for the top 40 cm. The carbon stock ratio of the SRC stand to the arable land was estimated to minimize the effect of site-related factors. The results of this analysis suggested that the ratio increased significantly with age after conversion for the top 10 cm of the soil, both for poplar and willow. A slight increase with age was also noticed at the deeper depths, but

  6. Biochar increases plant-available water in a sandy loam soil under an aerobic rice crop system

    NASA Astrophysics Data System (ADS)

    de Melo Carvalho, M. T.; de Holanda Nunes Maia, A.; Madari, B. E.; Bastiaans, L.; van Oort, P. A. J.; Heinemann, A. B.; Soler da Silva, M. A.; Petter, F. A.; Marimon, B. H., Jr.; Meinke, H.

    2014-09-01

    The main objective of this study was to assess the impact of biochar rate (0, 8, 16 and 32 Mg ha-1) on the water retention capacity (WRC) of a sandy loam Dystric Plinthosol. The applied biochar was a by-product of slow pyrolysis (∼450 °C) of eucalyptus wood, milled to pass through a 2000 μm sieve that resulted in a material with an intrinsic porosity ≤10 μm and a specific surface area of ∼3.2 m2 g-1. The biochar was incorporated into the top 15 cm of the soil under an aerobic rice system. Our study focused on both the effects on WRC and rice yields 2 and 3 years after its application. Undisturbed soil samples were collected from 16 plots in two soil layers (5-10 and 15-20 cm). Soil water retention curves were modelled using a nonlinear mixed model which appropriately accounts for uncertainties inherent of spatial variability and repeated measurements taken within a specific soil sample. We found an increase in plant-available water in the upper soil layer proportional to the rate of biochar, with about 0.8% for each Mg ha-1 biochar amendment 2 and 3 years after its application. The impact of biochar on soil WRC was most likely related to an effect in overall porosity of the sandy loam soil, which was evident from an increase in saturated soil moisture and macro porosity with 0.5 and 1.6% for each Mg ha-1 of biochar applied, respectively. The increment in soil WRC did not translate into an increase in rice yield, essentially because in both seasons the amount of rainfall during the critical period for rice production exceeded 650 mm. The use of biochar as a soil amendment can be a worthy strategy to guarantee yield stability under short-term water-limited conditions. Our findings raise the importance of assessing the feasibility of very high application rates of biochar and the inclusion of a detailed analysis of its physical and chemical properties as part of future investigations.

  7. The Transition to ICD-10-CM: Challenges for Pediatric Practice

    PubMed Central

    Zaman, Jeffrey; Nam, Hannah; Chae, Sae-Rom; Williams, Lauren; Mathew, Gina; Burton, Michael; Li, Jiarong “John”; Lussier, Yves A.

    2014-01-01

    BACKGROUND AND OBJECTIVES: Diagnostic codes are used widely within health care for billing, quality assessment, and to measure clinical outcomes. The US health care system will transition to the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM), in October 2015. Little is known about how this transition will affect pediatric practices. The objective of this study was to examine how the transition to ICD-10-CM may result in ambiguity of clinical information and financial disruption for pediatricians. METHODS: Using a statewide data set from Illinois Medicaid specified for pediatricians, 2708 International Classification of Diseases, Ninth Revision, Clinical Modification, diagnosis codes were identified. Diagnosis codes were categorized into 1 of 5 categories: identity, class-to-subclass, subclass-to-class, convoluted, and no translation. The convoluted and high-cost diagnostic codes (n = 636) were analyzed for accuracy and categorized into “information loss,” “overlapping categories,” “inconsistent,” and “consistent.” Finally, reimbursement by Medicaid was calculated for each category. RESULTS: Twenty-six percent of pediatric diagnosis codes are convoluted, which represents 21% of Illinois Medicaid pediatric patient encounters and 16% of reimbursement. The diagnosis codes represented by information loss (3.6%), overlapping categories (3.2%), and inconsistent (1.2%) represent 8% of Medicaid pediatric reimbursement. CONCLUSIONS: The potential for financial disruption and administrative errors from 8% of reimbursement diagnosis codes necessitates special attention to these codes in preparing for the transition to ICD-10-CM for pediatric practices. PMID:24918217

  8. Multiple precursors of secondary mineralogical assemblages in CM chondrites

    NASA Astrophysics Data System (ADS)

    Pignatelli, Isabella; Marrocchi, Yves; Vacher, Lionel. G.; Delon, RéMi; Gounelle, Matthieu

    2016-04-01

    We report a petrographic and mineralogical survey of tochilinite/cronstedtite intergrowths (TCIs) in Paris, a new CM chondrite considered to be the least altered CM identified to date. Our results indicate that type-I TCIs consist of compact tochilinite/cronstedtite rims surrounding Fe-Ni metal beads, thus confirming kamacite as the precursor of type-I TCIs. In contrast, type-II TCIs are characterized by complex compositional zoning composed of three different Fe-bearing secondary minerals: from the outside inwards, tochilinite, cronstedtite, and amakinite. Type-II TCIs present well-developed faces that allow a detailed morphological analysis to be performed in order to identify the precursors. The results demonstrate that type-II TCIs formed by pseudomorphism of the anhydrous silicates, olivine, and pyroxene. Hence, there is no apparent genetic relationship between type-I and type-II TCIs. In addition, the complex chemical zoning observed within type-II TCIs suggests that the alteration conditions evolved dramatically over time. At least three stages of alteration can be proposed, characterized by alteration fluids with varying compositions (1) Fe- and S-rich fluids; (2) S-poor and Fe- and Si-rich fluids; and (3) S- and Si-poor, Fe-rich fluids. The presence of unaltered silicates in close association with euhedral type-II TCIs suggests the existence of microenvironments during the first alteration stages of CM chondrites. In addition, the absence of Mg-bearing secondary minerals in Paris TCIs suggests that the Mg content increases during the course of alteration.

  9. [Carbon source utilization characteristics of microbial communities in a petroleum-contaminated soil in Daqing Oil Field, Northeast China].

    PubMed

    Yue, Bing-Bing; Li, Xin; Ren, Fang-Fei; Meng, Fan-Juan; Yin, Peng-Da; Zhang, Hui-Hui; Sun, Guang-Yu

    2011-12-01

    By using Biolog technique, this paper studied the carbon source utilization characteristics of microbial communities in different layers (0-10 cm, 10-20 cm, and 20-30 cm) of a petroleum-contaminated soil near an oil well having exploited for 36 years in Daqing Oil Field. Petroleum contamination enhanced the metabolic activity of the soil microbial communities obviously. In the three layers of the petroleum-contaminated soil, the metabolic activity of the microbes was higher than that of the control, and there existed significant differences between different layers of the petroleum-contaminated soil. The carbon source metabolic capacity of the microbes in different layers of the petroleum-contaminated soil was in the order of 20-30 cm > 10-20 cm > 0-10 cm. Petroleum contamination made the kinds of soil carbon source and the metabolic diversity of soil microbes increased, being more obvious in 10-20 cm and 20-30 cm soil layers but less change in 0-10 cm soil layer. In the contaminated soil, the majority of the carbon sources utilized by the microbes in 10-20 cm soil layer were carbohydrates instead of the carboxylic acids in non-contaminated soil, whereas the majority of the carbon substrates utilized in 20-30 cm soil layer were carboxylic acids. All the results suggested that petroleum-contaminated soil had its unique microbial community structure and peculiar microbial carbon source utilization characteristics.

  10. Performance of 30-cm ion thrusters with dished accelerator grids

    NASA Technical Reports Server (NTRS)

    Rawlin, V. K.

    1973-01-01

    Thirteen sets of dished accelerator grids were tested on five different 30-cm diameter bombardment thrustors to evaluate the effects of grid geometry variations on thrustor discharge chamber performance. The dished grid parameters varied were: grid-to-grid spacing, screen and accelerator grid hole-diameter, screen and accelerator open area fraction, compensation for beam divergence losses, and accelerator grid thickness. Also investigated were the effects on discharge chamber performance of main magnetic field changes, magnetic baffle current cathode pole piece length and cathode position.

  11. Performance of 30-cm ion thrusters with dished accelerator grids

    NASA Technical Reports Server (NTRS)

    Rawlin, V. K.

    1973-01-01

    Thirteen sets of dished accelerator grids were treated on five different 30 cm diameter bombardment thrusters to evaluate the effects of grid geometry variations on thruster discharge chamber performance. The dished grid parameters varied were: grid-to-grid spacing, screen and accelerator grid hole diameter, screen and accelerator open area fraction, compensation for beam divergence losses, and accelerator grid thickness. The effects on discharge chamber performance of main magnetic field changes, magnetic baffle current, cathode pole piece length and cathode position were also investigated.

  12. Studies of dished accelerator grids for 30-cm ion thrusters

    NASA Technical Reports Server (NTRS)

    Rawlin, V. K.

    1973-01-01

    Eighteen geometrically different sets of dished accelerator grids were tested on five 30-cm thrusters. The geometric variation of the grids included the grid-to-grid spacing, the screen and accelerator hole diameters and thicknesses, the screen and accelerator open area fractions, ratio of dish depth to dish diameter, compensation, and aperture shape. In general, the data taken over a range of beam currents for each grid set included the minimum total accelerating voltage required to extract a given beam current and the minimum accelerator grid voltage required to prevent electron backstreaming.

  13. Affordable échelle spectroscopy with a 60 cm telescope

    NASA Astrophysics Data System (ADS)

    Pribulla, T.; Garai, Z.; Hambálek, L.; Kollár, V.; Komžík, R.; Kundra, E.; Nedoroščík, J.; Sekeráš, M.; Vaňko, M

    2015-09-01

    A new fiber-fed spectrograph was installed at the 60 cm telescope of the Stará Lesná Observatory. The article presents tests of its performance (spectral resolution, signal-to-noise ratio, radial-velocity stability) and reports observations of selected variable stars and exoplanet host stars. First test observations show that the spectrograph is an ideal tool to observe bright eclipsing and spectroscopic binaries but also symbiotic and nova-like stars. The radial-velocity stability (60-80 ms-1) is sufficient to study spectroscopic binaries and to detect easily the orbital motion of hot-Jupiter extrasolar planets around bright stars.

  14. The 8-CM ion thruster characterization. [mercury ion engine

    NASA Technical Reports Server (NTRS)

    Wessel, F. J.; Williamson, W. S.

    1983-01-01

    The performance capabilities of the 8 cm diameter mercury ion thruster were increased by modifying the thruster operating parameters and component hardware. The initial performance levels, representative of the Hughes/NASA Lewis Research Center Ion Auxiliary Propulsion Subsystem (IAPS) thruster, were raised from the baseline values of thrust, T = 5 mN, and specific impulse, I sub sp = 2,900s, to thrust, T = 25 mN and specific impulse, I sub sp = 4,300 s. Performance characteristics including estmates of the erosion rates of various component surfaces are presented.

  15. Performance documentation of the engineering model 30-cm diameter thruster

    NASA Technical Reports Server (NTRS)

    Bechtel, R. T.; Rawlin, V. K.

    1976-01-01

    The results of extensive testing of two 30-cm ion thrusters which are virtually identical to the 900 series Engineering Model Thruster in an ongoing 15,000-hour life test are presented. Performance data for the nominal fullpower (2650 W) operating point; performance sensitivities to discharge voltage, discharge losses, accelerator voltage, and magnetic baffle current; and several power throttling techniques (maximum Isp, maximum thrust/power ratio, and two cases in between are included). Criteria for throttling are specified in terms of the screen power supply envelope, thruster operating limits, and control stability. In addition, reduced requirements for successful high voltage recycles are presented.

  16. Performance capabilities of the 8-cm mercury ion thruster

    NASA Technical Reports Server (NTRS)

    Mantenieks, M. A.

    1981-01-01

    A preliminary characterization of the performance capabilities of the 8-cm thruster in order to initiate an evaluation of its application to LSS propulsion requirements is presented. With minor thruster modifications, the thrust was increased by about a factor of four while the discharge voltage was reduced from 39 to 22 volts. The thruster was operated over a range of specific impulse of 1950 to 3040 seconds and a maximum total efficiency of about 54 percent was attained. Preliminary analysis of component lifetimes, as determined by temperature and spectroscopic line intensity measurements, indicated acceptable thruster lifetimes are anticipated at the high power level operation.

  17. Status of 30 cm mercury ion thruster development

    NASA Technical Reports Server (NTRS)

    Sovey, J. S.; King, H. J.

    1974-01-01

    Two engineering model 30-cm ion thrusters were assembled, calibrated, and qualification tested. This paper discusses the thruster design, performance, and power system. Test results include documentation of thrust losses due to doubly charged mercury ions and beam divergence by both direct thrust measurements and beam probes. Diagnostic vibration tests have led to improved designs of the thruster backplate structure, feed system, and harness. Thruster durability is being demonstrated over a thrust range of 97 to 113 mN at a specific impulse of about 2900 seconds. As of August 15, 1974, the thruster has successfully operated for over 4000 hours.

  18. Recycle Requirements for NASA's 30 cm Xenon Ion Thruster

    NASA Technical Reports Server (NTRS)

    Pinero, Luis R.; Rawlin, Vincent K.

    1994-01-01

    Electrical breakdowns have been observed during ion thruster operation. These breakdowns, or arcs, can be caused by several conditions. In flight systems, the power processing unit must be designed to handle these faults autonomously. This has a strong impact on power processor requirements and must be understood fully for the power processing unit being designed for the NASA Solar Electric Propulsion Technology Application Readiness program. In this study, fault conditions were investigated using a NASA 30 cm ion thruster and a power console. Power processing unit output specifications were defined based on the breakdown phenomena identified and characterized.

  19. Control of a 30 cm diameter mercury bombardment thruster

    NASA Technical Reports Server (NTRS)

    Terdan, F. F.; Bechtel, R. T.

    1973-01-01

    Increased thruster performance has made closed-loop automatic control more difficult than previously. Specifically, high perveance optics tend to make reliable recycling more difficult. Control logic functions were established for three automatic modes of operation of a 30-cm thruster using a power conditioner console with flight-like characteristics. The three modes provide (1) automatic startup to reach thermal stability, (2) steady-state closed-loop control, and (3) the reliable recycling of the high voltages following an arc breakdown to reestablish normal operation. Power supply impedance characteristics necessary for stable operation and the effect of the magnetic baffle on the reliable recycling was studied.

  20. Radiated and conducted EMI from a 30-cm ion thruster

    NASA Technical Reports Server (NTRS)

    Whittlesey, A. C.; Peer, W.

    1981-01-01

    In order to properly assess the interaction of a spacecraft with the EMI environment produced by an ion thruster, the EMI environment was characterized. Therefore, radiated and conducted emissions were measured from a 30-cm mercury ion thruster. The ion thruster beam current varied from zero to 2.0 amperes and the emissions were measured from 5 KHz to 200 MHz. Several different types of antennas were used to obtain the measurements. The various measurements that were made included: magnetic field due to neutralizer/beam current loop; radiated electric fields of thruster and plume; and conducted emissions on arc discharge, neutralizer keeper and magnetic baffle lines.

  1. Long lifetime hollow cathodes for 30-cm mercury ion thrusters

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.; Kerslake, W. R.

    1976-01-01

    An experimental investigation of hollow cathodes for 30-cm Hg bombardment thrusters was carried out. Both main and neutralizer cathode configurations were tested with both rolled foil inserts coated with low work function material and impregnated porous tungsten inserts. Temperature measurements of an impregnated insert at various positions in the cathode were made. These, along with the cathode thermal profile are presented. A theory for rolled foil and impregnated insert operation and lifetime in hollow cathodes is developed. Several endurance tests, as long as 18000 hours at emission currents of up to 12 amps were attained with no degradation in performance.

  2. Studies of dished accelerator grids for 30-cm ion thrusters

    NASA Technical Reports Server (NTRS)

    Rawlin, V. K.

    1973-01-01

    Geometrically different sets of dished accelerator grids were tested on five 30-cm thrusters. The geometric variation of the grids included the grid-to-grid spacing, the screen and accelerator hole diameters and thicknesses, the screen and accelerator open area fractions, ratio of dish depth to the dish diameter, compensation, and aperture shape. In general, the data taken over a range of beam currents for each grid set included the minimum total accelerating voltage required to extract a given beam current and the minimum accelerator grid voltage required to prevent electron backstreaming.

  3. Performance mapping of a 30 cm engineering model thruster

    NASA Technical Reports Server (NTRS)

    Poeschel, R. L.; Vahrenkamp, R. P.

    1975-01-01

    A 30 cm thruster representative of the engineering model design has been tested over a wide range of operating parameters to document performance characteristics such as electrical and propellant efficiencies, double ion and beam divergence thrust loss, component equilibrium temperatures, operational stability, etc. Data obtained show that optimum power throttling, in terms of maximum thruster efficiency, is not highly sensitive to parameter selection. Consequently, considerations of stability, discharge chamber erosion, thrust losses, etc. can be made the determining factors for parameter selection in power throttling operations. Options in parameter selection based on these considerations are discussed.

  4. The 100 cm solar telescope primary mirror study

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The manufacturing impact of primary mirror configuration on the performance of a 100 cm aperture solar telescope was studied. Three primary mirror configurations were considered: solid, standard lightweight, and mushroom. All of these are of low expansion material. Specifically, the study consisted of evaluating the mirrors with regard to: manufacturing metrology, manufacturing risk factors and ultimate quality assessment. As a result of this evaluation, a performance comparison of the configurations was made, and a recommendation of mirror configuration is the final output. These evaluations, comparisons and recommendations are discussed in detail. Other investigations were completed and are documented in the appendices.

  5. Human Being Imaging with cm-Wave UWB Radar

    NASA Astrophysics Data System (ADS)

    Yarovoy, A.; Zhuge, X.; Savelyev, T.; Matuzas, J.; Levitas, B.

    Possibilities of high-resolution human body imaging and concealed weapon detection using centimeter-wave microwave frequencies are investigated. Dependencies of the cross-range resolution of different imaging techniques on operational bandwidth, center frequency, imaging aperture size, and imaging topology have been studied. It has been demonstrated that the cross-range resolution of 2 cm can be achieved using frequencies below 10 GHz. These findings have been verified experimentally by producing high-resolution images of a foil-covered doll and some weapons.

  6. Park size and disturbance: impact on soil heterogeneity - a case study Tel-Aviv- Jaffa.

    NASA Astrophysics Data System (ADS)

    Zhevelev, Helena; Sarah, Pariente; Oz, Atar

    2015-04-01

    Parks and gardens are poly-functional elements of great importance in urban areas, and can be used for optimization of physical and social components in these areas. This study aimed to investigate alteration of soil properties with land usages within urban park and with area size of park. Ten parks differed by size (2 - 50 acres) were chosen, in random, in Tel-Aviv- Jaffa city. Soil was sampled in four microenvironments ((lawn, path, picnic and peripheral area (unorganized area) of each the park)), in three points and three depth (0-2, 5-10 and 10-20 cm). Penetration depth was measured in all point of sampling. For each soil sample electrical conductivity and organic matter content were determined. Averages of penetration depth drastically increased from the most disturbed microenvironments (path and picnic) to the less disturbed ones (lawn and peripheral). The maximal heterogeneity (by variances and percentiles) of penetration depth was found in the peripheral area. In this area, penetration depth increased with increasing park size, i.e., from 2.6 cm to 3.7 cm in the small and large parks, respectively. Averages of organic matter content and electrical conductivity decreased with soil depth in all microenvironments and increased with decreasing disturbance of microenvironments. Maximal heterogeneity for both of these properties was found in the picnic area. Increase of park size was accompanied by increasing of organic matter content in the upper depth in the peripheral area, i.e., from 2.4% in the small parks to 4.5% in the large ones. In all microenvironments the increasing of averages of all studied soil properties was accompanied by increasing heterogeneity, i.e., variances and upper percentiles. The increase in the heterogeneity of the studied soil properties is attributed to improved ecological soil status in the peripheral area, on the one hand, and to the high anthropogenic pressure in the picnic area, on the other. This means that the urban park offers

  7. Soil water repellency patterns following long-term irrigation with waste water in a sandy calcareous soil, SE Spain

    NASA Astrophysics Data System (ADS)

    Mataix-Solera, J.; García-Irles, L.; Morugán, A.; Doerr, S. H.; García-Orenes, F.; Atanassova, I.; Navarro, M. A.; Ayguadé, H.

    2009-04-01

    One of the consequences of long-term irrigation with waste water can be the development of soil water repellency (WR). Its emergence can affect soil-water balance, irrigation efficiency and crop yield. Water repellency development has been suggested to be controlled by parameters such as organic matter quantity and type present in the waste water, soil properties (particularly the texture), and the overall time period of irrigation. Here we examine the effect of long-term (~20 years) irrigation with low quality waste-water on soil wettability under a Populus alba tree stand used as a "green filter". The plot exhibited considerable micro-topography (ridges and furrows) and consisted of sandy calcareous soil (Xerofluvent). Water repellency and organic carbon content (OC) were studied in 160 samples taken from the plot and from an adjacent area used as control (no irrigated). From the control area 40 samples were taken from the first 5 cm of mineral soil (C samples). From the irrigated plot a total of 120 samples were collected. To account for the micro-topography of the terrain, 40 samples each were taken from ridges (R samples; 0-5 cm depth), furrows (F samples; 0-5 cm depth), and from furrows at depth (FD samples, 5-10 cm depth). Soil WR was assessed in the laboratory for all air dry samples using the water drop penetration time test (WDPT Test). Samples with WDPT ? 5 seconds were classified as non-repellent. Organic carbon content (OC) was analyzed in all samples by potassium dichromate oxidation method. We also carried out a detailed chemical characterisation of the organic matter in two furrow samples that exhibited contrasting wettability, but no major difference in OC content (F10: WDPT 9960s, OC 6.7%; F31: WDPT 10s, OC 7.5%). Following accelerated solvent extraction with Dichloro-methane/MeOH (95:5), the extract was analysed by GC-MS. All samples from the control area (C) were wettable (mean WDPT=1s). In the irrigated plot, water repellency was present for 48

  8. Passive microwave soil moisture research

    NASA Technical Reports Server (NTRS)

    Schmugge, T. J.; Oneill, P. E.; Wang, J. R.

    1985-01-01

    The AgRISTARS Soil Moisture Project has made significant progress in the quantification of microwave sensor capabilities for soil moisture remote sensing. The 21-cm wavelength has been verified to be the best single channel for radiometric observations of soil moisture. It has also been found that other remote sensing approaches used in conjunction with L-band passive data are more successful than multiple wavelength microwave radiometry in this application. AgRISTARS studies have also improved current understanding of noise factors affecting the interpretability of microwave emission data. The absorption of soil emission by vegetation has been quantified, although this effect is less important than absorption effects for microwave radiometry.

  9. Vertical distribution of soil removed by four species of burrowing rodents in disturbed and undisturbed soils.

    PubMed

    Reynolds, T D; Laundré, J W

    1988-04-01

    Burrow volumes were determined in disturbed and undisturbed soils for four species of rodents in southeastern Idaho. Comparisons were made between soil types for the average volume and the proportion of the total volume of soil excavated from 10-cm increments for each species, and the relative number of burrows and proportion of total soil removed from beneath the minimum thickness of soil covers over buried low-level radioactive wastes. Burrows of montane voles (Microtus montanus) and deer mice (Peromyscus maniculatus) rarely extended below 50 cm and neither volumes nor depths were influenced by soil disturbance. Townsend's ground squirrels (Spermophilus townsendii) had the deepest and most voluminous burrows that, along with Ord's kangaroo rat (Dipodomys ordii) burrows, were more prevalent beneath 50 cm in disturbed soils.

  10. Vertical distribution of soil removed by four species of burrowing rodents in disturbed and undisturbed soils

    SciTech Connect

    Reynolds, T.D.; Laundre, J.W.

    1988-04-01

    Burrow volumes were determined in disturbed and undisturbed soils for four species of rodents in southeastern Idaho. Comparisons were made between soil types for the average volume and the proportion of the total volume of soil excavated from 10-cm increments for each species, and the relative number of burrows and proportion of total soil removed from beneath the minimum thickness of soil covers over buried low-level radioactive wastes. Burrows of montane voles (Microtus montanus) and deer mice (Peromyscus maniculatus) rarely extended below 50 cm and neither volumes nor depths were influenced by soil disturbance. Townsend's ground squirrels (Spermophilus townsendii) had the deepest and most voluminous burrows that, along with Ord's kangaroo rat (Dipodomys ordii) burrows, were more prevalent beneath 50 cm in disturbed soils.

  11. Soil and Surface Runoff Phosphorus Relationships for Five Typical USA Midwest Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessively high soil P can increase P loss with surface runoff. This study used indoor rainfall simulations to characterize soil and runoff P relationships for five Midwest soils (Argiudoll, Calciaquaoll, Hapludalf, and two Hapludolls). Topsoil (15-cm depth, 241–289 g clay kg–1 and pH 6.0–8.0) was ...

  12. Measuring the Cosmological 21 cm Monopole with an Interferometer

    NASA Astrophysics Data System (ADS)

    Presley, Morgan E.; Liu, Adrian; Parsons, Aaron R.

    2015-08-01

    A measurement of the cosmological 21 {cm} signal remains a promising but as-of-yet unattained ambition of radio astronomy. A positive detection would provide direct observations of key unexplored epochs of our cosmic history, including the cosmic dark ages and reionization. In this paper, we concentrate on measurements of the spatial monopole of the 21 {cm} brightness temperature as a function of redshift (the “global signal”). Most global experiments to date have been single-element experiments. In this paper, we show how an interferometer can be designed to be sensitive to the monopole mode of the sky, thus providing an alternate approach to accessing the global signature. We provide simple rules of thumb for designing a global signal interferometer and use numerical simulations to show that a modest array of tightly packed antenna elements with moderately sized primary beams (FWHM of ∼ 40^\\circ ) can compete with typical single-element experiments in their ability to constrain phenomenological parameters pertaining to reionization and the pre-reionization era. We also provide a general data analysis framework for extracting the global signal from interferometric measurements (with analysis of single-element experiments arising as a special case) and discuss trade-offs with various data analysis choices. Given that interferometric measurements are able to avoid a number of systematics inherent in single-element experiments, our results suggest that interferometry ought to be explored as a complementary way to probe the global signal.

  13. Power processor for a 20CM ion thruster

    NASA Technical Reports Server (NTRS)

    Biess, J. J.; Schoenfeld, A. D.; Cohen, E.

    1973-01-01

    A power processor breadboard for the JPL 20CM Ion Engine was designed, fabricated, and tested to determine compliance with the electrical specification. The power processor breadboard used the silicon-controlled rectifier (SCR) series resonant inverter as the basic power stage to process all the power to the ion engine. The breadboard power processor was integrated with the JPL 20CM ion engine and complete testing was performed. The integration tests were performed without any silicon-controlled rectifier failure. This demonstrated the ruggedness of the series resonant inverter in protecting the switching elements during arcing in the ion engine. A method of fault clearing the ion engine and returning back to normal operation without elaborate sequencing and timing control logic was evolved. In this method, the main vaporizer was turned off and the discharge current limit was reduced when an overload existed on the screen/accelerator supply. After the high voltage returned to normal, both the main vaporizer and the discharge were returned to normal.

  14. Probing patchy reionization through τ-21 cm correlation statistics

    SciTech Connect

    Meerburg, P. Daniel; Spergel, David N.; Dvorkin, Cora E-mail: dns@astro.princeton.edu

    2013-12-20

    We consider the cross-correlation between free electrons and neutral hydrogen during the epoch of reionization (EoR). The free electrons are traced by the optical depth to reionization τ, while the neutral hydrogen can be observed through 21 cm photon emission. As expected, this correlation is sensitive to the detailed physics of reionization. Foremost, if reionization occurs through the merger of relatively large halos hosting an ionizing source, the free electrons and neutral hydrogen are anticorrelated for most of the reionization history. A positive contribution to the correlation can occur when the halos that can form an ionizing source are small. A measurement of this sign change in the cross-correlation could help disentangle the bias and the ionization history. We estimate the signal-to-noise ratio of the cross-correlation using the estimator for inhomogeneous reionization τ-hat {sub ℓm} proposed by Dvorkin and Smith. We find that with upcoming radio interferometers and cosmic microwave background (CMB) experiments, the cross-correlation is measurable going up to multipoles ℓ ∼ 1000. We also derive parameter constraints and conclude that, despite the foregrounds, the cross-correlation provides a complementary measurement of the EoR parameters to the 21 cm and CMB polarization autocorrelations expected to be observed in the coming decade.

  15. Characterization of an 8-cm Diameter Ion Source System

    NASA Technical Reports Server (NTRS)

    Li, Zhongmin; Hawk, C. W.; Hawk, Clark W.; Buttweiler, Mark S.; Williams, John D.; Buchholtz, Brett

    2005-01-01

    Results of tests characterizing an 8-cm diameter ion source are presented. The tests were conducted in three separate vacuum test facilities at the University of Alabama-Huntsville, Colorado State University, and L3 Communications' ETI division. Standard ion optics tests describing electron backstreaming and total-voltage-limited impingement current behavior as a function of beam current were used as guidelines for selecting operating conditions where more detailed ion beam measurements were performed. The ion beam was profiled using an in-vacuum actuating probe system to determine the total ion current density and the ion charge state distribution variation across the face of the ion source. Both current density and ExB probes were utilized. The ion current density data were used to obtain integrated beam current, beam flatness parameters, and general beam profile shapes. The ExB probe data were used to determine the ratio of doubly to singly charged ion current. The ion beam profile tests were performed at over six different operating points that spanned the expected operating range of the DAWN thrusters being developed at L3. The characterization tests described herein reveal that the 8-cm ion source is suitable for use in (a) validating plasma diagnostic equipment, (b) xenon ion sputtering and etching studies of spacecraft materials, (c) plasma physics research, and (d) the study of ion thruster optics at varying conditions.

  16. Presolar grains in the CM2 chondrite Sutter's Mill

    NASA Astrophysics Data System (ADS)

    Zhao, Xuchao; Lin, Yangting; Yin, Qing-Zhu; Zhang, Jianchao; Hao, Jialong; Zolensky, Michael; Jenniskens, Peter

    2014-11-01

    The Sutter's Mill (SM) carbonaceous chondrite is a regolith breccia, composed predominantly of CM2 clasts with varying degrees of aqueous alteration and thermal metamorphism. An investigation of presolar grains in four Sutter's Mill sections, SM43, SM51, SM2-4, and SM18, was carried out using NanoSIMS ion mapping technique. A total of 37 C-anomalous grains and one O-anomalous grain have been identified, indicating an abundance of 63 ppm for presolar C-anomalous grains and 2 ppm for presolar oxides. Thirty-one silicon carbide (SiC), five carbonaceous grains, and one Al-oxide (Al2O3) were confirmed based on their elemental compositions determined by C-N-Si and O-Si-Mg-Al isotopic measurements. The overall abundance of SiC grains in Sutter's Mill (55 ppm) is consistent with those in other CM chondrites. The absence of presolar silicates in Sutter's Mill suggests that they were destroyed by aqueous alteration on the parent asteroid. Furthermore, SM2-4 shows heterogeneous distributions of presolar SiC grains (12-54 ppm) in different matrix areas, indicating that the fine-grained matrix clasts come from different sources, with various thermal histories, in the solar nebula.

  17. Altimeter error sources at the 10-cm performance level

    NASA Technical Reports Server (NTRS)

    Martin, C. F.

    1977-01-01

    Error sources affecting the calibration and operational use of a 10 cm altimeter are examined to determine the magnitudes of current errors and the investigations necessary to reduce them to acceptable bounds. Errors considered include those affecting operational data pre-processing, and those affecting altitude bias determination, with error budgets developed for both. The most significant error sources affecting pre-processing are bias calibration, propagation corrections for the ionosphere, and measurement noise. No ionospheric models are currently validated at the required 10-25% accuracy level. The optimum smoothing to reduce the effects of measurement noise is investigated and found to be on the order of one second, based on the TASC model of geoid undulations. The 10 cm calibrations are found to be feasible only through the use of altimeter passes that are very high elevation for a tracking station which tracks very close to the time of altimeter track, such as a high elevation pass across the island of Bermuda. By far the largest error source, based on the current state-of-the-art, is the location of the island tracking station relative to mean sea level in the surrounding ocean areas.

  18. Electric prototype power processor for a 30cm ion thruster

    NASA Technical Reports Server (NTRS)

    Biess, J. J.; Inouye, L. Y.; Schoenfeld, A. D.

    1977-01-01

    An electrical prototype power processor unit was designed, fabricated and tested with a 30 cm mercury ion engine for primary space propulsion. The power processor unit used the thyristor series resonant inverter as the basic power stage for the high power beam and discharge supplies. A transistorized series resonant inverter processed the remaining power for the low power outputs. The power processor included a digital interface unit to process all input commands and internal telemetry signals so that electric propulsion systems could be operated with a central computer system. The electrical prototype unit included design improvement in the power components such as thyristors, transistors, filters and resonant capacitors, and power transformers and inductors in order to reduce component weight, to minimize losses, and to control the component temperature rise. A design analysis for the electrical prototype is also presented on the component weight, losses, part count and reliability estimate. The electrical prototype was tested in a thermal vacuum environment. Integration tests were performed with a 30 cm ion engine and demonstrated operational compatibility. Electromagnetic interference data was also recorded on the design to provide information for spacecraft integration.

  19. Spatial and Seasonal Variability of Extreme Soil Temperature in Croatia

    NASA Astrophysics Data System (ADS)

    Sviličić, Petra; Vučetić, Višnja

    2015-04-01

    In terms of taking the temperature of the Earth in Croatia, first measurements began in 1898 in Križevci, but systematic measurements of soil temperature started in 1951. Today, the measurements are performed at 55 meteorological stations. The process of setting up, calibration, measurement, input, control and data processing is done entirely within the Meteorological and Hydrological Service. Due to the lack of funds, but also as a consequence of the Homeland War, network density in some areas is very rare, leading to aggravating circumstances during analysis. Also, certain temperature series are incomplete or are interrupted and therefore the number of long-term temperature series is very small. This particularly presents problems in coastal area, which is geographically diversified and is very difficult to do a thorough analysis of the area. Using mercury angle geothermometer daily at 7, 14 and 21 h CET, thermal state of soil is measured at 2, 5, 10, 20, 30, 50 and 100 cm depth. Thermometers are placed on the bare ground within the meteorological circle and facing north to reduce the direct impact of solar radiation. Lack of term measurements is noticed in the analysis of extreme soil temperatures, which are not real extreme values, but derived from three observational times. On the basis of fifty year series (1961-2010) at 23 stations, the analysis of trends of the surface maximal and minimal soil temperature, as well as the appearance of freezing is presented. Trends were determined by Sen's slope estimator, and statistical significance on 5% level was determined using the Mann-Kendall test. It was observed that the variability of the surface maximal soil temperature on an annual and seasonal level is much higher than those for surface minimal soil temperature. Trends in the recent period show a statistically significant increase in the maximal soil temperature in the eastern and the coastal regions, especially in the spring and summer season. Also, the

  20. P-O-rich sulfide phase in CM chondrites: Constraints on its origin on the CM parent body

    NASA Astrophysics Data System (ADS)

    Zhang, Ai-Cheng; Itoh, Shoichi; Yurimoto, Hisayoshi; Hsu, Wei-Biao; Wang, Ru-Cheng; Taylor, Lawrence A.

    2016-01-01

    CM chondrites are a group of primitive meteorites that have recorded the alteration history of the early solar system. We report the occurrence, chemistry, and oxygen isotopic compositions of P-O-rich sulfide phase in two CM chondrites (Grove Mountains [GRV] 021536 and Murchison). This P-O-rich sulfide is a polycrystalline aggregate of nanometer-size grains. It occurs as isolated particles or aggregates in both CM chondrites. These grains, in the matrix and in type-I chondrules from Murchison, were partially altered into tochilinite; however, grains enclosed by Ca-carbonate are much less altered. This P-O-rich sulfide in Murchison is closely associated with magnetite, FeNi phosphide, brezinaite (Cr3S4), and eskolaite (Cr2O3). In addition to sulfur as the major component, this sulfide contains ~6.3 wt% O, ~5.4 wt% P, and minor amounts of hydrogen. Analyses of oxygen isotopes by SIMS resulted in an average δ18O value of -22.5 ‰ and an average Δ17O value of 0.2 ± 9.2 ‰ (2σ). Limited variations in both chemical compositions and electron-diffraction patterns imply that the P-O-rich sulfide may be a single phase rather than a polyphase mixture. Several features indicate that this P-O-rich sulfide phase formed at low temperature on the parent body, most likely through the alteration of FeNi metal (a) close association with other low-temperature alteration products, (b) the presence of hydrogen, (c) high Δ17O values and the presence in altered mesostasis of type-I chondrules and absence in type-II chondrules. The textural relations of the P-O-rich sulfide and other low-temperature minerals reveal at least three episodic-alteration events on the parent body of CM chondrites (1) formation of P-O-rich sulfide during sulfur-rich aqueous alteration of P-rich FeNi metal, (2) formation of Ca-carbonate during local carbonation, and (3) alteration of P-O-rich sulfide and formation of tochilinite during a period of late-stage intensive aqueous alteration.

  1. Healthy Homes/Healthy Kids: A Randomized Trial of a Pediatric Primary Care Based Obesity Prevention Intervention for At-Risk 5-10 Year Olds

    PubMed Central

    Sherwood, Nancy E.; Levy, Rona L.; Langer, Shelby L.; Senso, Meghan M.; Crain, A. Lauren; Hayes, Marcia G.; Anderson, Julie D.; Seburg, Elisabeth M.; Jeffery, Robert W.

    2014-01-01

    Pediatric primary care is an important setting in which to address obesity prevention, yet relatively few interventions have been evaluated and even fewer have been shown to be effective. The development and evaluation of cost-effective approaches to obesity prevention that leverage opportunities of direct access to families in the pediatric primary care setting, overcome barriers to implementation in busy practice settings, and facilitate sustained involvement of parents is an important public health priority. The goal of the Healthy Homes/Healthy Kids (HHHK 5-10) randomized controlled trial is to evaluate the efficacy of a relatively low-cost primary care-based obesity prevention intervention aimed at 5 to 10 year old children who are at risk for obesity. Four hundred twenty one parent/child dyads were recruited and randomized to either the obesity prevention arm or a contact control condition that focuses on safety and injury prevention. The HHHK 5-10 obesity prevention intervention combines brief counseling with a pediatric primary care provider during routine well-child visits and follow-up telephone coaching that supports parents in making home environmental changes to support healthful eating, activity patterns, and body weight. The contact control condition combines the same provider counseling with telephone coaching focused on safety and injury prevention messages. This manuscript describes the study design and baseline characteristics of participants enrolled in the HHHK 5-10 trial. PMID:23816490

  2. Healthy Homes/Healthy Kids: a randomized trial of a pediatric primary care-based obesity prevention intervention for at-risk 5-10 year olds.

    PubMed

    Sherwood, Nancy E; Levy, Rona L; Langer, Shelby L; Senso, Meghan M; Crain, A Lauren; Hayes, Marcia G; Anderson, Julie D; Seburg, Elisabeth M; Jeffery, Robert W

    2013-09-01

    Pediatric primary care is an important setting in which to address obesity prevention, yet relatively few interventions have been evaluated and even fewer have been shown to be effective. The development and evaluation of cost-effective approaches to obesity prevention that leverage opportunities of direct access to families in the pediatric primary care setting, overcome barriers to implementation in busy practice settings, and facilitate sustained involvement of parents is an important public health priority. The goal of the Healthy Homes/Healthy Kids (HHHK 5-10) randomized controlled trial is to evaluate the efficacy of a relatively low-cost primary care-based obesity prevention intervention aimed at 5 to 10 year old children who are at risk for obesity. Four hundred twenty one parent/child dyads were recruited and randomized to either the obesity prevention arm or a Contact Control condition that focuses on safety and injury prevention. The HHHK 5-10 obesity prevention intervention combines brief counseling with a pediatric primary care provider during routine well child visits and follow-up telephone coaching that supports parents in making home environmental changes to support healthful eating, activity patterns, and body weight. The Contact Control condition combines the same provider counseling with telephone coaching focused on safety and injury prevention messages. This manuscript describes the study design and baseline characteristics of participants enrolled in the HHHK 5-10 trial. PMID:23816490

  3. Weekly cycle of magnetic characteristics of the daily PM2.5 and PM2.5-10 in Beijing, China

    NASA Astrophysics Data System (ADS)

    Shi, Meinan; Wu, Huaichun; Zhang, Shihong; Li, Haiyan; Yang, Tianshui; Liu, Wei; Liu, He

    2014-12-01

    In recent years, Beijing has been shown to suffer one of the most serious air pollution problems of any major world city. The concentrations of particulate matter (PM) pollutants, PM2.5-10 and PM2.5, are commonly used as air pollution indexes. We conducted a detailed environmental magnetism study to investigate possible sources of air pollution in Beijing, China, using 283 pairs of the PM2.5 and PM2.5-10 samples collected daily from July 2010 to June 2011. Rock magnetic measurements, including magnetic susceptibility, anhysteretic remanent magnetization, isothermal remanent magnetization, saturation isothermal remanent magnetization, hysteresis loops, first-order reversal curves (FORCs), and thermomagnetism, indicate that the main magnetic mineral is low-coercivity pseudo-single domain (PSD) magnetite. Scanning electron microscope (SEM) observations and energy dispersive X-ray spectroscopy (EDS) analyses on the PM indicate that the major magnetic phase is coarse-grained magnetite, which is most likely from automobile exhausts and braking system debris. Magnetic parameters of PM2.5 and PM2.5-10 show significant seasonal patterns that may be attributed to domestic heating enhancing magnetization of the PM during late autumn to early spring. Power spectral analyses and box-whisker plots indicate that the magnetic parameters have strong weekly variations that may be due to traffic emissions. These results indicate that magnetic parameters can be used as efficient proxies for monitoring Beijing's air pollution, and that the atmospheric environment may be improved by controlling vehicle emissions.

  4. Soil Decomposition of Added Organic C in an Organic Farming System

    NASA Astrophysics Data System (ADS)

    Kpomblekou-A, Kokoasse; Sissoko, Alassane; McElhenney, Wendell

    2015-04-01

    In the United States, large quantities of poultry waste are added every year to soil under organic management. Decomposition of the added organic C releases plant nutrients, promotes soil structure, and plays a vital role in the soil food web. In organic agriculture the added C serves as the only source of nutrients for plant growth. Thus understanding the decomposition rates of such C in organic farming systems are critical in making recommendations of organic inputs to organic producers. We investigated and compared relative accumulation and decomposition of organic C in an organic farming system trial at the George Washington Carver Agricultural Experiment Station at Tuskegee, Alabama on a Marvyn sandy loam (fine-loamy, kaolinitic, thermic, Typic Kanhapludults) soil. The experimental design was a randomized complete block with four replicates and four treatments. The main plot (54' × 20') was split into three equal subplots to plant three sweet potato cultivars. The treatments included a weed (control with no cover crop, no fertilizer), crimson clover alone (CC), crimson clover plus broiler litter (BL), and crimson clover plus NPK mineral fertilizers (NPK). For five years, late in fall, the field was planted with crimson clover (Trifolium incarnatum L) that was cut with a mower and incorporated into soil the following spring. Moreover, broiler litter (4.65 Mg ha-1) or ammonium nitrate (150 kg N ha-1), triple super phosphate (120 kg P2O5 ha-1), and potassium chloride (160 kg K2O ha-1) were applied to the BL or the NPK plot and planted with sweet potato. Just before harvest, six soil samples were collected within the two middle rows of each sweet potato plot with an auger at incremental depths of 0-1, 1-2, 2-3, 3-5, 5-10, and 10-15 cm. Samples from each subplot and depth were composited and mixed in a plastic bag. The samples were sieved moist through a

  5. Variability in Soil Properties at Different Spatial Scales (1 m to 1 km) in a Deciduous Forest Ecosystem

    SciTech Connect

    Garten Jr, Charles T; Kang, S.; Brice, Deanne Jane; Schadt, Christopher Warren; Zhou, Jizhong

    2007-01-01

    The purpose of this research was to test the hypothesis that variability in 11 soil properties, related to soil texture and soil C and N, would increase from small (1 m) to large (1 km) spatial scales in a temperate, mixed-hardwood forest ecosystem in east Tennessee, USA. The results were somewhat surprising and indicated that a fundamental assumption in geospatial analysis, namely that variability increases with increasing spatial scale, did not apply for at least five of the 11 soil properties measured over a 0.5-km2 area. Composite mineral soil samples (15 cm deep) were collected at 1, 5, 10, 50, 250, and 500 m distances from a center point along transects in a north, south, east, and westerly direction. A null hypothesis of equal variance at different spatial scales was rejected (P{le}0.05) for mineral soil C concentration, silt content, and the C-to-N ratios in particulate organic matter (POM), mineral-associated organic matter (MOM), and whole surface soil. Results from different tests of spatial variation, based on coefficients of variation or a Mantel test, led to similar conclusions about measurement variability and geographic distance for eight of the 11 variables examined. Measurements of mineral soil C and N concentrations, C concentrations in MOM, extractable soil NH{sub 4}-N, and clay contents were just as variable at smaller scales (1-10 m) as they were at larger scales (50-500 m). On the other hand, measurement variation in mineral soil C-to-N ratios, MOM C-to-N ratios, and the fraction of soil C in POM clearly increased from smaller to larger spatial scales. With the exception of extractable soil NH4-N, measured soil properties in the forest ecosystem could be estimated (with 95% confidence) to within 15% of their true mean with a relatively modest number of sampling points (n{le}25). For some variables, scaling up variation from smaller to larger spatial domains within the ecosystem could be relatively easy because small-scale variation may be

  6. Biochemical activities in soil overlying Paraho processed oil shale

    SciTech Connect

    Sorensen, D.L.

    1982-01-01

    Microbial activity development in soil materials placed over processed oil shale is vital to the plant litter decomposition, cycling of nutrients, and soil organic matter accumulation and maintenance. Samples collected in the summers of 1979, 1980, and 1981 from revegetated soil 30-, 61-, and 91-cm deep overlying spent oil shale in the Piceance Basin of northwestern Colorado were assayed for dehydrogenease activity with glucose and without glucose, for phosphatase activity, and for acetylene reduction activity. Initial ammonium and nitrite nitrogen oxidation rates and potential denitrification rates were determined in 1981. Zymogenous dehydrogenase activity, phosphatase activity, nitrogenase activity, potential denitrification rates, and direct microscopic counts were lower in surface soil 30 cm deep, and were frequently lower in surface soil 61 cm deep over processed shale than in a surface-disturbed control area soil. Apparently, microbial activities are stressed in these more shallow replaced soils. Soil 61 cm deep over a coarse-rock capillary barrier separating the soil from the spent shale, frequently had improved biochemical activity. Initial ammonium and nitrite nitrogen oxidation rates were lower in all replaced soils than in the disturbed control soil. Soil core samples taken in 1981 were assayed for dehydrogenase and phosphatase activities, viable bacteria, and viable fungal propagules. In general, microbial activity decreased quickly below the surface. At depths greater than 45 cm, microbial activities were similar in buried spent shale and surface-disturbed control soil.

  7. 15 cm cusped magnetic field mercury ion thruster research

    NASA Technical Reports Server (NTRS)

    Beattie, J. R.; Wilbur, P. J.

    1975-01-01

    The importance of achieving a uniform current density in the exhaust beam of an electrostatic ion thruster is discussed in terms of thrust level and accelerator grid lifetime. A neutral residence time approach is used to propose a magnetic field geometry which should produce a highly uniform beam current density. The discharge chamber length to diameter ratio is shown to be an important optimization parameter and experimental evaluation of the cusped field thruster over a wide range of this parameter is presented. Beam profile measurements 5 cm downstream of the accelerator grid indicate a beam profile flatness parameter which is 25% greater than the SERT II value. Flatness parameters extrapolated to the plane of the accelerator grid are demonstrated to be as high as 0.9.

  8. Gravitational-wave detection using redshifted 21-cm observations

    SciTech Connect

    Bharadwaj, Somnath; Guha Sarkar, Tapomoy

    2009-06-15

    A gravitational-wave traversing the line of sight to a distant source produces a frequency shift which contributes to redshift space distortion. As a consequence, gravitational waves are imprinted as density fluctuations in redshift space. The gravitational-wave contribution to the redshift space power spectrum has a different {mu} dependence as compared to the dominant contribution from peculiar velocities. This, in principle, allows the two signals to be separated. The prospect of a detection is most favorable at the highest observable redshift z. Observations of redshifted 21-cm radiation from neutral hydrogen hold the possibility of probing very high redshifts. We consider the possibility of detecting primordial gravitational waves using the redshift space neutral hydrogen power spectrum. However, we find that the gravitational-wave signal, though present, will not be detectable on superhorizon scales because of cosmic variance and on subhorizon scales where the signal is highly suppressed.

  9. Translation Optics for 30 cm Ion Engine Thrust Vector Control

    NASA Technical Reports Server (NTRS)

    Haag, Thomas

    2002-01-01

    Data were obtained from a 30 cm xenon ion thruster in which the accelerator grid was translated in the radial plane. The thruster was operated at three different throttle power levels, and the accelerator grid was incrementally translated in the X, Y, and azimuthal directions. Plume data was obtained downstream from the thruster using a Faraday probe mounted to a positioning system. Successive probe sweeps revealed variations in the plume direction. Thruster perveance, electron backstreaming limit, accelerator current, and plume deflection angle were taken at each power level, and for each accelerator grid position. Results showed that the thruster plume could easily be deflected up to six degrees without a prohibitive increase in accelerator impingement current. Results were similar in both X and Y direction.

  10. An H I 21-cm line survey of evolved stars

    NASA Astrophysics Data System (ADS)

    Gérard, E.; Le Bertre, T.; Libert, Y.

    2011-12-01

    The HI line at 21 cm is a tracer of circumstellar matter around AGB stars, and especially of the matter located at large distances (0.1-1 pc) from the central stars. It can give unique information on the kinematics and on the physical conditions in the outer parts of circumstellar shells and in the regions where stellar matter is injected into the interstellar medium. However this tracer has not been much used up to now, due to the difficulty of separating the genuine circumstellar emission from the interstellar one. With the Nançay Radiotelescope we are carrying out a survey of the HI emission in a large sample of evolved stars. We report on recent progresses of this long term programme, with emphasis on S-type stars.

  11. Autumn at Titan's South Pole: The 220 cm-1 Cloud

    NASA Astrophysics Data System (ADS)

    Jennings, D. E.; Cottini, V.; Achterberg, R. K.; Anderson, C. M.; Flasar, F. M.; de Kok, R. J.; Teanby, N. A.; Coustenis, A.; Vinatier, S.

    2015-10-01

    Beginning in 2012 an atmospheric cloud known by its far-infrared emission has formed rapidly at Tit an's South Pole [1, 2]. The build-up of this condensate is a result of deepening temperatures and a gathering of gases as Winter approaches. Emission from the cloud in the south has been doubling each year since 2012, in contrast to the north where it has halved every 3.8 years since 2004. The morphology of the cloud in the south is quite different from that in the north. In the north, the cloud has extended over the whole polar region beyond 55 N, whereas in the south the cloud has been confined to within about 10 degrees of the pole. The cloud in the north has had the form of a uniform hood, whereas the southern cloud has been much more complex. A map from December 2014,recorded by the Composite Infrared Spectrometer (CIRS) on Cassini, showed the 220 cm-1 emission coming from a distinct ring with a maximum at about 80 S. In contrast, emissions from the gases HC3N, C4H2 and C6H6 peaked near the pole and had a ring at 70 S. The 220 cm-1 ring at 80 S coincided with the minimum in the gas emission pattern. The80 S condensate ring encompassed the vortex cloud seen by the Cassini Imaging Science Subsystem (ISS) and Visible and Infrared Mapping Spectrometer (VIMS)[3, 4]. Both the 220 cm-1 ring and the gas "bull's-eye" pattern were centered on a point that was shifted from the geographic South Pole by 4 degrees in the direction of the Sun. This corresponds to the overall tilt of Titan's atmosphere discovered from temperature maps early in the Cassini mission by Achterberg et al. [5]. The tilt may be reinforced by the presumably twice-yearly (north and south) spin-up of the atmosphere at the autumnal pole. The bull's-eye pattern of the gas emissions can be explained by the retrieved abundance distributions, which are maximum near the pole and decrease sharply toward lower latitudes, together with temperatures that are minimum at the pole and increase toward lower latitudes

  12. Rb-Sr studies of CI and CM chondrites

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, D. W.; Wetherill, G. W.

    1979-01-01

    Rb-Sr whole rock analyses have been performed on 2 CI and 3 CM chondrites. Four of these stones (Ivuna, Orgueil, Cold Bokkeveld and Erakot) were previously studied in this laboratory and were shown to be discordant from a 4.6 Gyr isochron. The fifth, Murchison, was not previously studied. The new data support the discordance of the first four stones, and indicate that Murchison is also discordant. Studies of Sr isotope ratios in unspiked Orgueil show that the discordance is not due to inhomogeneities in the Sr-84/Sr-86 ratio caused by incomplete mixing of nucleosynthesis products. In order to gauge the effects of weathering, two leaching experiments were performed on fresh, interior samples of Murchison; one for a period of 1.5 hr and the other for 117 hr. The results indicate that the relative solubility of nonradiogenic Sr is approximately twice that of Rb and radiogenic Sr is more soluble than the nonradiogenic Sr.

  13. The Murchison Widefield Array 21 cm Power Spectrum Analysis Methodology

    NASA Astrophysics Data System (ADS)

    Jacobs, Daniel C.; Hazelton, B. J.; Trott, C. M.; Dillon, Joshua S.; Pindor, B.; Sullivan, I. S.; Pober, J. C.; Barry, N.; Beardsley, A. P.; Bernardi, G.; Bowman, Judd D.; Briggs, F.; Cappallo, R. J.; Carroll, P.; Corey, B. E.; de Oliveira-Costa, A.; Emrich, D.; Ewall-Wice, A.; Feng, L.; Gaensler, B. M.; Goeke, R.; Greenhill, L. J.; Hewitt, J. N.; Hurley-Walker, N.; Johnston-Hollitt, M.; Kaplan, D. L.; Kasper, J. C.; Kim, HS; Kratzenberg, E.; Lenc, E.; Line, J.; Loeb, A.; Lonsdale, C. J.; Lynch, M. J.; McKinley, B.; McWhirter, S. R.; Mitchell, D. A.; Morales, M. F.; Morgan, E.; Neben, A. R.; Thyagarajan, N.; Oberoi, D.; Offringa, A. R.; Ord, S. M.; Paul, S.; Prabu, T.; Procopio, P.; Riding, J.; Rogers, A. E. E.; Roshi, A.; Udaya Shankar, N.; Sethi, Shiv K.; Srivani, K. S.; Subrahmanyan, R.; Tegmark, M.; Tingay, S. J.; Waterson, M.; Wayth, R. B.; Webster, R. L.; Whitney, A. R.; Williams, A.; Williams, C. L.; Wu, C.; Wyithe, J. S. B.

    2016-07-01

    We present the 21 cm power spectrum analysis approach of the Murchison Widefield Array Epoch of Reionization project. In this paper, we compare the outputs of multiple pipelines for the purpose of validating statistical limits cosmological hydrogen at redshifts between 6 and 12. Multiple independent data calibration and reduction pipelines are used to make power spectrum limits on a fiducial night of data. Comparing the outputs of imaging and power spectrum stages highlights differences in calibration, foreground subtraction, and power spectrum calculation. The power spectra found using these different methods span a space defined by the various tradeoffs between speed, accuracy, and systematic control. Lessons learned from comparing the pipelines range from the algorithmic to the prosaically mundane; all demonstrate the many pitfalls of neglecting reproducibility. We briefly discuss the way these different methods attempt to handle the question of evaluating a significant detection in the presence of foregrounds.

  14. Viscoelastic hydrodynamic interactions and anomalous CM diffusion in polymer melts

    NASA Astrophysics Data System (ADS)

    Meyer, Hendrik

    We have recently discovered that anomalous center-of-mass (CM) diffusion occurring on intermediate time scales in polymer melts can be explained by the interplay of viscoelastic and hydrodynamic interactions (VHI). The theory has been solved for unentangled melts in 3D and 2D and excellent agreement between theory and simulation is found, also for alkanes with a force field optimized from neutron scattering. The physical mechanism considers that hydrodynamic interactions are not screened: they are time dependent because of increasing viscosity before the terminal relaxation time. The VHI are generally active in melts of any topology. They are most important at early times well before the terminal relaxation time and thus affect the nanosecond time range typically observable in dynamic neutron scattering experiments. We illustrate the effects with recent molecular dynamics simulations of linear, ring and star polymers. Work performed with A.N. Semenov and J. Farago.

  15. A young region on Enceladus revealed by 2 cm radiometry?

    NASA Astrophysics Data System (ADS)

    Ries, P.; Janssen, M.

    2014-04-01

    On 5 November 2011, the Cassini spacecraft had a flyby of Enceladus dedicated to its synthetic aperture radar (SAR) instrument. In the course of that flyby, approximately 80% of Enceladus' surface was also observed serendipitously with the microwave radiometer operating concurrently at 2.2 cm. The radiometry data is analyzed and shown to drop sharply in the leading hemisphere's smooth terrain. This drop is also demonstrated in a series of unresolved distant radiometry measurements spread out over the ten years of the Cassini mission. However, the anomaly is absent from distant unresolved RADAR measurements and not visible in SAR imaging. The anomaly is most likely caused by a young surface (<100MYr in age) which has not yet been processed by micrometeoroid impacts below the electromagnetic skin depth (3 m).

  16. Direct thrust measurement of a 30-cm ion thruster

    NASA Technical Reports Server (NTRS)

    Banks, B.; Rawlin, V.; Weigand, A.; Walker, J.

    1975-01-01

    A direct thrust measurement of a 30-cm diameter ion thruster was accomplished by means of a laser interferometer thrust stand. The thruster was supported in a pendulum manner by three 3.65-m long wires. Electrical power was provided by means of 18 mercury filled pots. A movable 23-button planar probe rake was used to determine thrust loss due to ion beam divergence. Values of thrust, thrust loss due to ion beam divergence, and thrust loss due to multiple ionization were measured for ion beam currents ranging from 0.5 to 2.5 A. Measured thrust values indicate an accuracy of approximately 1% and are in good agreement with thrust values calculated by indirect measurements.

  17. Hollow cathode restartable 15 cm diameter ion thruster

    NASA Technical Reports Server (NTRS)

    Wilbur, P. J.

    1973-01-01

    The effects of substituting high perveance dished grids for low perveance flat ones on performance variables and plasma properties within a 15 cm modified SERT II thruster are discussed. Results suggest good performance may be achieved as an ion thruster is throttled if the screen grid transparency is decreased with propellant flow rate. Thruster startup tests, which employ a pulsed high voltage tickler electrode between the keeper and the cathode to initiate the discharge, are described. High startup reliability at cathode tip temperatures of about 500 C without excessive component wear over 2000 startup cycles is demonstrated. Testing of a single cusp magnetic field concept of discharge plasma containment is discussed. A theory which explains the observed behavior of the device is presented and proposed thruster modifications and future testing plans are discussed.

  18. HIBAYES: Global 21-cm Bayesian Monte-Carlo Model Fitting

    NASA Astrophysics Data System (ADS)

    Zwart, Jonathan T. L.; Price, Daniel; Bernardi, Gianni

    2016-06-01

    HIBAYES implements fully-Bayesian extraction of the sky-averaged (global) 21-cm signal from the Cosmic Dawn and Epoch of Reionization in the presence of foreground emission. User-defined likelihood and prior functions are called by the sampler PyMultiNest (ascl:1606.005) in order to jointly explore the full (signal plus foreground) posterior probability distribution and evaluate the Bayesian evidence for a given model. Implemented models, for simulation and fitting, include gaussians (HI signal) and polynomials (foregrounds). Some simple plotting and analysis tools are supplied. The code can be extended to other models (physical or empirical), to incorporate data from other experiments, or to use alternative Monte-Carlo sampling engines as required.

  19. Astronaut Risk Levels During Crew Module (CM) Land Landing

    NASA Technical Reports Server (NTRS)

    Lawrence, Charles; Carney, Kelly S.; Littell, Justin

    2007-01-01

    The NASA Engineering Safety Center (NESC) is investigating the merits of water and land landings for the crew exploration vehicle (CEV). The merits of these two options are being studied in terms of cost and risk to the astronauts, vehicle, support personnel, and general public. The objective of the present work is to determine the astronaut dynamic response index (DRI), which measures injury risks. Risks are determined for a range of vertical and horizontal landing velocities. A structural model of the crew module (CM) is developed and computational simulations are performed using a transient dynamic simulation analysis code (LS-DYNA) to determine acceleration profiles. Landing acceleration profiles are input in a human factors model that determines astronaut risk levels. Details of the modeling approach, the resulting accelerations, and astronaut risk levels are provided.

  20. Very Large Array observations of Uranus at 2. 0 cm

    SciTech Connect

    Berge, G.L.; Muhleman, D.O.; Linfield, R.P.

    1988-07-01

    Radio observations of Uranus obtained at 2.0 cm with the B configuration of the VLA during April 1985 are reported. The calibration and data-reduction procedures are described in detail, and the results are presented in tables, maps, and graphs and compared with IRIS 44-micron observations (Hanel et al., 1986). Features discussed include highest brightness centered on the pole rather than on the subearth point, a decrease in brightness temperature (by up to 9 K) at latitudes between -20 and -50 deg (well correlated with the IRIS data), and disk-center position (corrected for the observed radio asymmetry) in good agreement with that found on the basis of the outer contours of the image. 15 references.

  1. Cosmic (Super)String Constraints from 21 cm Radiation

    SciTech Connect

    Khatri, Rishi; Wandelt, Benjamin D.

    2008-03-07

    We calculate the contribution of cosmic strings arising from a phase transition in the early Universe, or cosmic superstrings arising from brane inflation, to the cosmic 21 cm power spectrum at redshifts z{>=}30. Future experiments can exploit this effect to constrain the cosmic string tension G{mu} and probe virtually the entire brane inflation model space allowed by current observations. Although current experiments with a collecting area of {approx}1 km{sup 2} will not provide any useful constraints, future experiments with a collecting area of 10{sup 4}-10{sup 6} km{sup 2} covering the cleanest 10% of the sky can, in principle, constrain cosmic strings with tension G{mu} > or approx. 10{sup -10}-10{sup -12} (superstring/phase transition mass scale >10{sup 13} GeV)

  2. Cosmic (Super)String Constraints from 21 cm Radiation.

    PubMed

    Khatri, Rishi; Wandelt, Benjamin D

    2008-03-01

    We calculate the contribution of cosmic strings arising from a phase transition in the early Universe, or cosmic superstrings arising from brane inflation, to the cosmic 21 cm power spectrum at redshifts z > or =30. Future experiments can exploit this effect to constrain the cosmic string tension G mu and probe virtually the entire brane inflation model space allowed by current observations. Although current experiments with a collecting area of approximately 1 km2 will not provide any useful constraints, future experiments with a collecting area of 10(4)-10(6) km2 covering the cleanest 10% of the sky can, in principle, constrain cosmic strings with tension G mu > or = 10(-10)-10(-12) (superstring/phase transition mass scale >10(13) GeV). PMID:18352691

  3. Direct thrust measurement of a 30-cm ion thruster

    NASA Technical Reports Server (NTRS)

    Banks, B.; Rawlin, V.; Weigand, A. J.; Walker, J.

    1975-01-01

    A direct thrust measurement of a 30-cm diameter ion thruster was accomplished by means of a laser interferometer thrust stand. The thruster was supported in a pendulum manner by three 3.65-m long wires. Electrical power was provided by means of 18 mercury filled pots. A movable 23-button planar probe rake was used to determine thrust loss due to ion beam divergence. Values of thrust, thrust loss due to ion beam divergence, and thrust loss due to multiple ionization were measured for ion beam currents ranging from 0.5 A to 2.5 A. Measured thrust values indicate an accuracy of approximately 1% and are in good agreement with thrust values calculated by indirect measurements.

  4. A dual frequency 10 cm Doppler weather radar

    NASA Astrophysics Data System (ADS)

    Glover, K. M.; Armstrong, G. M.; Bishop, A. W.; Banis, K. J.

    A summary is given of the design concepts underlying a new 10-cm band dual frequency Doppler weather radar under development at the Air Force Geophysics Laboratory. Primary emphasis in the design is placed on the system performance in a clutter environment, and the technique used to extend the radar's unambiguous range and velocity span is an important, but secondary, consideration. The design includes the use of fault tolerance and/or fault location methods at critical locations in the system and automated calibration techniques for quasi-continuous monitoring of system performance. The approach followed for minimizing range and velocity ambiguities used in this radar is a uniform pulse train version of the Doviak et al. (1978) dual sampling (batch) technique.

  5. Soil carbon stock and soil characteristics at Tasik Chini Forest Reserve, Pahang, Malaysia

    NASA Astrophysics Data System (ADS)

    Nur Aqlili Riana, R.; Sahibin A., R.

    2015-09-01

    This study was carried out to determine soil carbon stock and soil characteristic at Tasik Chini Forest Reserve (TCFR), Pahang. A total of 10 (20 m x 25 m) permanent sampling plot was selected randomly within the area of TCFR. Soil samples were taken from all subplots using dutch auger based on soil depth of 0-20cm, 20-40cm, 40-60cm. Soil parameters determined were size distribution, soil water content, bulk density, organic matter, organic carbon content, pH and electrical conductivity. All parameters were determined following their respective standard methods. Results obtained showed that the soil in TCFR was dominated by clay texture (40%), followed by sandy clay loam (30%), loam (20%). Silty clay, clay loam and sandy loam constitutes about 10% of the soil texture. Range of mean percentage of organic matter and bulk density are from 2.42±0.06% to 11.64±0.39% and 1.01 to 1.04 (gcm-ł), respectively. Soil pH are relatively very acidic and mean of electrical conductivity is low. Soil carbon content ranged from 0.83±0.03 to 1.87±0.41%. All soil parameter showed a decreasing trend with depth except electrical conductivity. ANOVA test of mean percentage of organic matter, soil water content, soil pH and electrical conductivity showed a significant difference between plot (p<0.05). However there are no significant difference of mean bulk density between plots (p>0.05). There are no significant difference in mean percentage of soil water content, organic matter and bulk density between three different depth (p>0.05). There were a significant difference on percentage of soil carbon organic between plots and depth. The mean of soil organic carbon stock in soil to a depth of 60 cm calculated was 35.50 t/ha.

  6. Estimating toxic damage to soil ecosystems from soil organic matter profiles

    USGS Publications Warehouse

    Beyer, W.N.

    2001-01-01

    Concentrations of particulate and total organic matter were measured in upper soil profiles at 26 sites as a potential means to identify toxic damage to soil ecosystems. Because soil organic matter plays a role in cycling nutrients, aerating soil, retaining water, and maintaining tilth, a significant reduction in organic matter content in a soil profile is not just evidence of a change in ecosystem function, but of damage to that soil ecosystem. Reference sites were selected for comparison to contaminated sites, and additional sites were selected to illustrate how variables other than environmental contaminants might affect the Soil organic matter profile. The survey was undertaken on the supposition that environmental contaminants and other stressors reduce the activity of earthworms and other macrofauna, inhibiting the incorporation of organic matter into the soil profile. The profiles of the unstressed soils showed a continuous decrease in organic matter content from the uppermost mineral soil layer (0-2.5 cm) down to 15 cm. Stressed soils showed an abrupt decrease in soil organic matter content below a depth of 2.5 cm. The 2.5-5.0 cm layer of stressed soils--such as found in a pine barren, an orchard, sites contaminated with zinc, and a site with compacted soil--had less than 4% total organic matter and less than 1% particulate organic matter. However, damaged soil ecosystems were best identified by comparison of their profiles to the profiles of closely matched reference soils, rather than by comparison to these absolute values. The presence or absence of earthworms offered a partial explanation of observed differences in soil organic matter profiles.

  7. Performance tests for the NASA Ames Research Center 20 cm x 40 cm oscillating flow wind tunnel

    NASA Technical Reports Server (NTRS)

    Cook, W. J.; Giddings, T. A.

    1984-01-01

    An evaluation is presented of initial tests conducted to assess the performance of the NASA Ames 20 cm x 40 cm oscillating flow wind tunnel. The features of the tunnel are described and two aspects of tunnel operation are discussed. The first is an assessment of the steady mainstream and boundary layer flows and the second deals with oscillating mainstream and boundary layer flows. Experimental results indicate that in steady flow the test section mainstream velocity is uniform in the flow direction and in cross section. The freestream turbulence intensity is about 0.2 percent. With minor exceptions the steady turbulent boundary layer generated on the top wall of the test section exhibits the characteristics of a zero pressure gradient turbulent boundary layer generated on a flat plate. The tunnel was designed to generate sinusoidal oscillating mainstream flows. Experiments confirm that the tunnel produces sinusoidal mainstream velocity variations for the range of frequencies (up to 15 Hz). The results of this study demonstrate that the tunnel essentially produces the flows that it was designed to produce.

  8. Tillage and liming effects on aggregate distribution and associated carbon and nitrogen in acid soils of SW Spain

    NASA Astrophysics Data System (ADS)

    Gómez-Paccard, Clara; Zabaleta, Javier; Benito, Marta; León, Paloma; Mariscal-Sancho, Ignacio; Espejo, Rafael; Hontoria, Chiquinquirá

    2013-04-01

    Beneficial effects of conservation tillage are well known on a wide variety of environmental aspects. The lack of ploughing in no till systems conserves soil structure, enhances the accumulation of organic carbon in the surface layer and promotes the development of soil microorganisms. On the other hand, liming is a common practice in acid soils. Lime raises the pH, reduces Al toxicity enhancing root development, but controversial results have been found about the effects of liming on soil structure. Ultisols from SW of Spain present severe chemical constraints as poor nutrient availability and high Al contents in the exchange complex. On the other hand, traditional practices as conventional tillage led to a dramatic decrease on soil organic carbon and a degraded soil structure. No till plus liming might be recommendable to achieve a sustainable and productive agriculture in these particular soils, but little is known about the effect of these practices on soil structure when applied together. The aim of this study was to evaluate the effect of traditional tillage (TT) versus no tillage (NT), and liming versus no liming on aggregate size distribution and associated carbon and nitrogen. The study was conducted on a Plinthic Palexerult (Soil Survey Staff, 1999) in the Cañamero's Raña (SW Spain) under Mediterranean climate (mean annual temperature: 15.0° C; mean annual precipitation: 869 mm). The experimental design was a split-plot with four replications. The main factor was tillage (no till versus traditional till) while the second was the inclusion or not of Ca-amendment (sugar foam plus red gypsum). Samples were collected in 2011 after six years of treatment at a 0-5, 5-10 and 10-25 cm depths. The aggregate distribution was determined by wet sieving method to separate four aggregate size classes: (i) >2000 µm (large macroaggregates), (ii) 250-2000 µm (small macroaggregates), (iii) 53-250 µm (microaggregates), (iv) <53 µm (silt and clay fraction). Soil

  9. Nutrient and hydrology effects on soil respiration in a northern Everglades marsh.

    PubMed

    DeBusk, W F; Reddy, K R

    2003-01-01

    Microbial respiration in peat and overlying plant litter, as influenced by water level and phosphorus enrichment, was evaluated for an Everglades (Florida, USA) marsh ecosystem by measuring CO2 and CH4 release from soil-water microcosms. Intact cores of peat, overlying plant litter, and surface water were collected at seven locations in cattail (Typha domingensis Pers.) and sawgrass (Cladium jamaicense Crantz) stands along a phosphorus (P) enrichment gradient in Water Conservation Area 2A (WCA-2A). Each soil-water microcosm was outfitted with a controlled air circulation system whereby outflow gas from the headspace could be analyzed for CO2 and CH4 to determine flux of C from the soil-water column to the atmosphere. Gaseous C flux was determined for flooded conditions (10-cm water depth) and for water levels of 0, 5, 10, and 15 cm below the peat surface. Overall, decreasing water level resulted in significantly increased C flux, although rates were significantly higher under flooded conditions than under nonflooded, saturated-soil conditions, presumably due to O2 availability associated with algal photosynthesis within the litter layer in the water column. Carbon flux decreased significantly for sites increasingly distant from the primary hydrologic and nutrient inflows to WCA-2A. The microcosm study demonstrated that the C turnover rate was significantly increased by accelerated nutrient loading to the marsh, and was further enhanced by decreasing water level under drained conditions. Our results also demonstrated that photosynthesis within the water column is a potentially important regulator of C mineralization rate in the litter layer of the marsh system.

  10. Long-term effects of deep soil loosening on root distribution and soil physical parameters in compacted lignite mine soils

    NASA Astrophysics Data System (ADS)

    Badorreck, Annika; Krümmelbein, Julia; Raab, Thomas

    2015-04-01

    Soil compaction is a major problem of soils on dumped mining substrates in Lusatia, Germany. Deep ripping and cultivation of deep rooting plant species are considered to be effective ways of agricultural recultivation. Six years after experiment start, we studied the effect of initial deep soil loosening (i.e. down to 65 cm) on root systems of rye (Secale cereale) and alfalfa (Medicago sativa) and on soil physical parameters. We conducted a soil monolith sampling for each treatment (deep loosened and unloosened) and for each plant species (in three replicates, respectively) to determine root diameter, length density and dry mass as well as soil bulk density. Further soil physical analysis comprised water retention, hydraulic conductivity and texture in three depths. The results showed different reactions of the root systems of rye and alfalfa six years after deep ripping. In the loosened soil the root biomass of the rye was lower in depths of 20-40 cm and the root biomass of alfalfa was also decreased in depths of 20-50 cm together with a lower root diameter for both plant species. Moreover, total and fine root length density was higher for alfalfa and vice versa for rye. The soil physical parameters such as bulk density showed fewer differences, despite a higher bulk density in 30-40cm for the deep loosened rye plot which indicates a more pronounced plough pan.

  11. Organic carbon, water repellency and soil stability to slaking at aggregate and intra-aggregate scales

    NASA Astrophysics Data System (ADS)

    Jordán López, Antonio; García-Moreno, Jorge; Gordillo-Rivero, Ángel J.; Zavala, Lorena M.; Cerdà, Artemi; Alanís, Nancy; Jiménez-Compán, Elizabeth

    2015-04-01

    intensity of WR in aggregates of different sizes. [ii] the intra-aggregate distribution of OC and the intensity of WR and [iii] the structural stability of soil aggregates relative to the OC content and the intensity of WR in soils under different crops (apricot, citrus and wheat) and different treatments (conventional tilling and mulching). Soil samples were collected from an experimental area (Luvic Calcisols and Calcic Luvisols) in the province of Sevilla (Southern Spain) under different crops (apricot, citrus and wheat) and different management types (conventional tillage with moldboard plow) and mulching (no-tilling and addition of wheat residues at rates varying between 5 and 8 Mg/ha/year). At each sampling site, soil blocks (50 cm long × 50 cm wide × 10 cm deep) were carefully collected to avoid disturbance of aggregates as much as possible and transported to the laboratory. At field moist condition, undisturbed soil aggregates were separated by hand. In order to avoid possible interferences due to disturbance by handling, aggregates broken during this process were discarded. Individual aggregates were arranged in paper trays and air-dried during 7 days under laboratory standard conditions. After air-drying, part of each sample was carefully divided for different analyses: [i] part of the original samples was sieved (2 mm) to eliminate coarse soil particles and homogenized for characterization of OC and N contents, C/N ratio and texture; [ii] part of the aggregates were dry-sieved (0.25-0.5, 0.5-1 and 1-2 mm) or measured with a caliper (2-5, 5-10 and 10-15 mm) and separated in different sieve-size classes for determination of WR and OC content; [iii] aggregates 10-15 mm in size were selected for obtaining aggregate layers using a soil aggregate erosion (SAE) apparatus and WR and OC content were determined at each layer; finally, [iv] in order to study the relation between stability to slaking, WR and OC, these properties were determined in 90 air-dried aggregates

  12. Soil adherence to human skin

    SciTech Connect

    Driver, J.H.; Konz, J.J.; Whitmyre, G.K. )

    1989-12-01

    Dermal exposure to soils contaminated with toxic chemicals represents a potential public health hazard. These soils, contaminated with chemicals such as PCBs and dioxins, may be found at various locations throughout the US. Furthermore, dermal contact with pesticide-containing particles and contaminated soil particles is of importance for exposures to agricultural workers who reenter fields after pesticide application. With respect to dermal exposure to pesticide-contaminated particulate matter, several occurrences of human toxicity to ethyl parathion in citrus groves have been reported. These exposures resulted from dermal contact with high concentrations of the toxic transformation product paraoxon in soil dust contaminated as a result of application of pesticide to the overhead foliage of trees. To assess dermal exposure to chemically-contaminated soil at sites of concern, dermal adherence of soil must be determined prior to the assessment of dermal absorption. The purpose of the experiment reported herein was to determine the amount of soil (mg/cm{sup 2}) that adheres to adult hands under various soil conditions. These conditions include the type of soil, the organic content of the soil, and the particle size of the soil.

  13. Soil 13C Dynamics in Aggregates Across a Soil Profile Under an Established Miscanthus System

    NASA Astrophysics Data System (ADS)

    Dondini, M.; Groenigen, K. J.; Jones, M.

    2008-12-01

    Soils are the largest pool of terrestrial organic carbon (C), containing nearly three times the amount of C as the atmosphere. Environmental changes that affect soil C dynamics could slow down the rise in atmospheric CO2 and associated warming by promoting soil C storage. Our capacity to predict the consequences for global change therefore depends on a better understanding of the distribution and controls of soil organic C and how vegetation change may affect SOC distributions. One land cover change of particular interest involves the establishment of bio energy crop stands. The full mitigation potential of bio energy crops cannot be considered without taking into account their effect on soil C dynamics. Miscanthus, a perennial C4 grass from Eastern Asia, has recently received considerable interest as a bio-energy crop. For that reason, we analyzed the C content and the 13C signatures across the soil profile in a 14 year old Miscanthus system, established on former arable land. We combined SOM fractionation techniques by size and density, allowing us to investigate small shifts in soil C stores that would be significant in the long term, but that might not be detected by conventional methodologies. The 13C signal of the various SOM fractions allowed us to distinguish between Miscanthus-derived vs. native soil organic C. Soils under Miscanthus contained 796 g C/m2 in the 0-15 cm layer, and 1233g C/m2 in the 15- 30 cm layer. These values are significantly higher than soil C contents in the arable land. Macroaggregates under Miscanthus contain more than twice as much C compared to arable land, showing a decrease in soil C content with decreasing aggregate size. These differences are largely caused by soil C storage in the microaggregate within macroaggregates fraction. Under Miscanthus, this fraction contains 440 g C/m2 and 488 g C/m2 at 0-15 cm and 15-30 cm respectively, while under the arable land it has mean values of 174 g C/m2 and 353 g C/m2. Our data suggest a

  14. Herbicide sorption coefficients in relation to soil properties and terrain attributes on a cultivated prairie

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The sorption of the herbicides 2,4-D and glyphosate in soil was quantified for 286 surface soil samples (0-15 cm) collected in a 10 m X 10 m grid across a heavily-eroded undulating calcareous prairie landscape. At each sampling point soil organic carbon content, soil carbonate content, soil pH, till...

  15. A 1.3 cm line survey toward IRC +10216

    NASA Astrophysics Data System (ADS)

    Gong, Y.; Henkel, C.; Spezzano, S.; Thorwirth, S.; Menten, K. M.; Wyrowski, F.; Mao, R. Q.; Klein, B.

    2015-02-01

    Context. IRC +10216 is the prototypical carbon star exhibiting an extended molecular circumstellar envelope. Its spectral properties are therefore the template for an entire class of objects. Aims: The main goal is to systematically study the λ ~ 1.3 cm spectral line characteristics of IRC +10216. Methods: We carried out a spectral line survey with the Effelsberg-100 m telescope toward IRC +10216. It covers the frequency range between 17.8 GHz and 26.3 GHz (K-band). Results: In the circumstellar shell of IRC +10216, we find 78 spectral lines, among which 12 remain unidentified. The identified lines are assigned to 18 different molecules and radicals. A total of 23 lines from species known to exist in this envelope are detected for the first time outside the solar system and there are additional 20 lines first detected in IRC +10216. The potential orgin of "U" lines is also discussed. Assuming local thermodynamic equilibrium (LTE), we then determine rotational temperatures and column densities of 17 detected molecules. Molecular abundances relative to H2 are also estimated. A non-LTE analysis of NH3 shows that the bulk of its emission arises from the inner envelope with a kinetic temperature of 70 ± 20 K. Evidence for NH3 emitting gas with higher kinetic temperature is also obtained, and potential abundance differences between various 13C-bearing isotopologues of HC5N are evaluated. Overall, the isotopic 12C/13C ratio is estimated to be 49 ± 9. Finally, a comparison of detected molecules in the λ ~ 1.3 cm range with the dark cloud TMC-1 indicates that silicate-bearing molecules are more predominant in IRC +10216. Appendices are available in electronic form at http://www.aanda.orgSpectra as FITS files are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/574/A56

  16. Modeling Soil Pore Oxygen in Restored Wetlands

    NASA Astrophysics Data System (ADS)

    Rubol, S.; Loecke, T.; Burgin, A. J.; Franz, T.

    2015-12-01

    Soil pore oxygen (O2) is usually modeled indirectly as a function of soil moisture. However, using soil moisture to describe the oxic /anoxic status of a soil may not be sufficient accurate, especially when soil pore O2 rapidly changes, as following hydrological forcing. As first step, we use the dataset collected in the constructed wetland near Dayton, OH, by Loecke and Burgin, to reconstruct the environmental functions and re-aeration status of the soil. The dataset consist of 24 Apogee sensors and 24 soil moisture and temperature sensors located at 10 cm depth in upland, transitional and submerged zone (see Figure 1). Data were recorded over two years at temporal interval of 30 minutes. Then, we explore the capability of existing biogeochemical models to predict metabolic activity and the soil pore O2. Figure1: Restored wetland field site with soil O2 sensors (yellow stars) in upland (red), transitional (green) and submerged (blue) zones.

  17. Electrical and physical characterization of the Al{sub 2}O{sub 3}/p-GaSb interface for 1%, 5%, 10%, and 22% (NH{sub 4}){sub 2}S surface treatments

    SciTech Connect

    Peralagu, Uthayasankaran Thayne, Iain G.; Povey, Ian M.; Carolan, Patrick; Lin, Jun; Hurley, Paul K.; Contreras-Guerrero, Rocio; Droopad, Ravi

    2014-10-20

    In this work, the impact of ammonium sulfide ((NH{sub 4}){sub 2}S) surface treatment on the electrical passivation of the Al{sub 2}O{sub 3}/p-GaSb interface is studied for varying sulfide concentrations. Prior to atomic layer deposition of Al{sub 2}O{sub 3}, GaSb surfaces were treated in 1%, 5%, 10%, and 22% (NH{sub 4}){sub 2}S solutions for 10 min at 295 K. The smallest stretch-out and flatband voltage shifts coupled with the largest capacitance swing, as indicated by capacitance-voltage (CV) measurements, were obtained for the 1% treatment. The resulting interface defect trap density (D{sub it}) distribution showed a minimum value of 4 × 10{sup 12 }cm{sup −2}eV{sup −1} at E{sub v} + 0.27 eV. Transmission electron microscopy and atomic force microscopy examination revealed the formation of interfacial layers and increased roughness at the Al{sub 2}O{sub 3}/p-GaSb interface of samples treated with 10% and 22% (NH{sub 4}){sub 2}S. In combination, these effects degrade the interface quality as reflected in the CV characteristics.

  18. Conjugate 18 cm OH satellite lines at a cosmological distance.

    PubMed

    Kanekar, Nissim; Chengalur, Jayaram N; Ghosh, Tapasi

    2004-07-30

    We have detected the two 18 cm OH satellite lines from the z approximately 0.247 source PKS1413+135, the 1720 MHz line in emission and the 1612 MHz line in absorption. The 1720 MHz luminosity is L(OH) approximately 354L (center dot in circle), more than an order of magnitude larger than that of any other known 1720 MHz maser. The profiles of the two satellite lines are conjugate, implying that they arise in the same gas. This allows us to test for any changes in the values of fundamental constants without being affected by systematic uncertainties arising from relative motions between the gas clouds in which the different lines arise. Our data constrain changes in G identical with g(p)[alpha(2)/y](1.849), where y identical with m(e)/m(p); we find DeltaG/G=2.2+/-3.8 x 10(-5), consistent with no changes in alpha, g(p), and y.

  19. Piezo-Operated Shutter Mechanism Moves 1.5 cm

    NASA Technical Reports Server (NTRS)

    Glaser, Robert; Bamford, Robert

    2005-01-01

    The figure shows parts of a shutter mechanism designed to satisfy a number of requirements specific to its original intended application as a component of an atomic clock to be flown in outer space. The mechanism may also be suitable for use in laboratory and industrial vacuum systems on Earth for which there are similar requirements. The requirements include the following: a) To alternately close, then open, a 1.5-cm-diameter optical aperture twice per second, with a stroke time of no more than 15 ms, during a total operational lifetime of at least a year; b) To attenuate light by a factor of at least 1012 when in the closed position; c) To generate little or no magnetic field; d) To be capable of withstanding bakeout at a temperature of 200 C to minimize outgassing during subsequent operation in an ultrahigh vacuum; and e) To fit within a diameter of 12 in. (=305 mm) a size limit dictated by the size of an associated magnetic shield. The light-attenuation requirement is satisfied by use of overlapping shutter blades. The closure of the aperture involves, among other things, insertion of a single shutter blade between a pair of shutter blades. The requirement to minimize the magnetic field is satisfied by use of piezoelectric actuators. Because piezoelectric actuators cannot withstand bakeout, they must be mounted outside the vacuum chamber, and, hence, motion must be transmitted from the actuators to the shutter levers via a vacuum-chamber-wall diaphragm.

  20. Microbiological study of the Murchison CM2 meteorite

    NASA Astrophysics Data System (ADS)

    Pikuta, Elena V.; Hoover, Richard B.

    2012-10-01

    In 1864, Louis Pasteur attempted to cultivate living microorganisms from pristine samples of the Orgueil CI1 carbonaceous meteorite. His results were negative and never published, but recorded it in his laboratory notebooks. At that time, only aerobic liquid or agar-based organic reach media were used, as his research on anaerobes had just started. In our laboratory the Murchison CM2 carbonaceous meteorite was selected to expand on these studies for microbiological study by cultivation on anaerobic mineral media. Since the surface could have been more easily contaminated, interior fragments of a sample of the Murchison meteorite were extracted and crushed under sterile conditions. The resulting powder was then mixed in anoxic medium and injected into Hungate tubes containing anaerobic media with various growth substrates at different pH and salinity and incubated at different temperatures. The goal of the experiments was to determine if living cells would grow from the material of freshly fractured interior fragments of the stone. If any growth occurred, work could then be carried out to assess the nature of the environmental contamination by observations of the culture growth (rates of speed and biodiversity); live/dead fluorescent staining to determine contamination level and DNA analysis to establish the microbial species present. In this paper we report the results of that study.

  1. Sensing and characterization of explosive vapors near 700 cm -1

    NASA Astrophysics Data System (ADS)

    Ford, Alan R.; Reeve, Scott W.

    2007-04-01

    One of the technological challenges associated with trace vapor detection of explosive materials are the relatively low vapor pressures exhibited by most energetic materials under ambient conditions. For example, the vapor pressure for TNT is ~10 ppbv at room temperature, a concentration near the Limit of Detection for many of the technologies currently being deployed. In the case of improvised explosive devices, the clandestine nature of the device further serves to exacerbate the vapor pressure issue. Interestingly, the gold standard in explosives detection remains the trained canine nose. While there is still some debate as to what the dog actually smells, recent studies have indicated the alert response is triggered, not by the vapor presence of a specific explosive compound but, by a characteristic bouquet of odors from chemical impurities used to manufacture and process the explosives. Here we present high resolution infrared data for several of these volatile organic compounds in the 700 cm -1 region required for real time optical sensing of energetic materials.

  2. CM and DM in an ISO R and D Environment

    NASA Technical Reports Server (NTRS)

    Crowley, Sandra L.

    2000-01-01

    ISO 9000 - a common buzz word in industry is making inroads to government agencies. The National Aeronautics and Space Agency (NASA) achieved ISO 9001 certification at each of its nine (9) Centers and Headquarters in 1998-1999. NASA Glenn Research Center (GRC) was recommended for certification in September 1999. Since then, each of the Centers has been going through the semi-annual surveillance audits. Growing out of the manufacturing industry, successful application of the international quality standard to a research and development (R&D) environment has had its challenges. This paper will address how GRC applied Configuration Management (CM) and Data (or Document) Management (DM) to meet challenges to achieve ISO certification. One of the first challenges was to fit the ISO 9001-1994 elements to the GRC environment. Some of the elements fit well-Management Responsibility (4.1), Internal Audits (4.17), Document and Data Control (4.5). Other elements were not suited or applied easily to the R&D environment-Servicing (4.19), Statistical Techniques (4.20). Since GRC "builds" only one or two items at a time, these elements were considered not applicable to the environment.

  3. Ion thruster system (8-cm) cyclic endurance test

    NASA Technical Reports Server (NTRS)

    Dulgeroff, C. R.; Beattie, J. R.; Poeschel, R. L.; Hyman, J., Jr.

    1984-01-01

    This report describes the qualification test of an Engineering-Model 5-mN-thrust 8-cm-diameter mercury ion thruster which is representative of the Ion Auxiliary Propulsion System (IAPS) thrusters. Two of these thrusters are scheduled for future flight test. The cyclic endurance test described herein was a ground-based test performed in a vacuum facility with a liquid-nitrogen-cooled cryo-surface and a frozen mercury target. The Power Electronics Unit, Beam Shield, Gimal, and Propellant Tank that were used with the thruster in the endurance test are also similar to those of the IAPS. The IAPS thruster that will undergo the longest beam-on-time during the actual space test will be subjected to 7,055 hours of beam-on-time and 2,557 cycles during the flight test. The endurance test was successfully concluded when the mercury in the IAPS Propellant Tank was consumed. At that time, 8,471 hours of beam-on-time and 599 cycles had been accumulated. Subsequent post-test-evaluation operations were performed (without breaking vacuum) which extended the test values to 652 cycles and 9,489 hours of beam-on-time. The Power Electronic Unit (PEU) and thruster were in the same vacuum chamber throughout the test. The PEU accumulated 10,268 hr of test time with high voltage applied to the operating thruster or dummy load.

  4. The 15 cm mercury ion thruster research 1975

    NASA Technical Reports Server (NTRS)

    Wilbur, P. J.

    1975-01-01

    Doubly charged ion current measurements in the beam of a SERT II thruster are shown to introduce corrections which bring its calculated thrust into close agreement with that measured during flight testing. A theoretical model of doubly charged ion production and loss in mercury electron bombardment thrusters is discussed and is shown to yield doubly-to-singly charged ion density ratios that agree with experimental measurements obtained on a 15 cm diameter thruster over a range of operating conditions. Single cusp magnetic field thruster operation is discussed and measured ion beam profiles, performance data, doubly charged ion densities, and discharge plasma characteristics are presented for a range of operating conditions and thruster geometries. Variations in the characteristics of this thruster are compared to those observed in the divergent field thruster and the cusped field thruster is shown to yield flatter ion beam profiles at about the same discharge power and propellant utilization operating point. An ion optics test program is described and the measured effects of grid system dimensions on ion beamlet half angle and diameter are examined. The effectiveness of hollow cathode startup using a thermionically emitting filament within the cathode is examined over a range of mercury flow rates and compared to results obtained with a high voltage tickler startup technique. Results of cathode plasma property measurement tests conducted within the cathode are presented.

  5. Changes in the properties of soils in a solonetz soil complex thirty years after reclamation

    NASA Astrophysics Data System (ADS)

    Kalinichenko, V. P.; Sharshak, V. K.; Mironchenko, S. F.; Chernenko, V. V.; Ladan, E. P.; Genev, E. D.; Illarionov, V. V.; Udalov, A. V.; Udalov, V. V.; Kippel, E. V.

    2014-04-01

    The long-term (30 year) dynamics of a solonetz soil complex composed of solonetzic light chestnut soils and chestnut solonetzes under standard conditions and with the application of agromeliorative measures are considered. When the standard zonal agricultural practice is used, the soils of the solonetzic complex have unfavorable agrophysical, chemical, and physicochemical properties and low productivity. After 30 years of the standard three-level tillage of the soils to a depth of 40-45 cm, the productivity of the biogeocenosis decreased. Thirty years after a single rotary-milling subsoil treatment of the 20- to 45-cm soil layer using a milling tool FS-1.3, there were no morphological features pointing to the restoration of the solonetzic process. The humus content in the 0-to 20-cm and 20-to 40-cm soil layers was 2.3 and 1.7%, respectively; the content of adsorbed Na+ in the 20-to 30-cm layer was 11.6% of the total exchange capacity, or 38% lower than its content in the reference soil. The additional yield reached 30-70% and more of that obtained with the standard agricultural technology used during the whole period under investigation. The method of systems biogeotechnology (systems bio-geo engineering) is proposed as a method for the preventive control of soil evolution and the maintenance of the stability and high productivity of the soil cover.

  6. Application of HYDRUS 1D model for assessment of phenol-soil adsorption dynamics.

    PubMed

    Pal, Supriya; Mukherjee, Somnath; Ghosh, Sudipta

    2014-04-01

    Laboratory-scale batch, vertical, and horizontal column experiments were conducted to investigate the attenuative capacity of a fine-grained clayey soil of local origin in the surrounding of a steel plant wastewater discharge site in West Bengal, India, for removal of phenol. Linear, Langmuir, and Freundlich isotherm plots from batch experimental data revealed that Freundlich isotherm model was reasonably fitted (R (2) = 0.94). The breakthrough column experiments were also carried out with different soil bed heights (5, 10, and 15 cm) under uniform flow to study the hydraulic movements of phenol by evaluating time concentration flow behavior using bromide as a tracer. The horizontal migration test was also conducted in the laboratory using adsorptive phenol and nonreactive bromide tracer to explore the movement of solute in a horizontal distance. The hydrodynamic dispersion coefficients (D) in the vertical and horizontal directions in the soil were estimated using nonlinear least-square parameter optimization method in CXTFIT model. In addition, the equilibrium convection dispersion model in HYDRUS 1D was also examined to simulate the fate and transport of phenol in vertical and horizontal directions using Freundlich isotherm constants and estimated hydrodynamic parameters as input in the model. The model efficacy and validation were examined through statistical parameters such as the coefficient of determination (R (2)), root mean square error and design of index (d). PMID:24407784

  7. Soil and Rock Physical Properties at the Mars Exploration Rovers Landing Sites

    NASA Astrophysics Data System (ADS)

    Ming, D.; Athena Science Team

    2004-05-01

    Soil and rock physical properties are being investigated by the Mars Exploration Rovers (MER) at Gusev crater (Spirit) and Meridiani Planum (Opportunity). These investigations are being conducted by the MER Athena Science Payload and the mobility systems on each rover. Physical properties of soil units are characterized by observations of wheel tracks (sinkage and tread casts). Images of rover wheel tracks in Gusev crater suggested a variety of surface textures. Traverses through depressions resulted in well-defined wheel track casts, suggesting that finer-grained materials accumulate in these depressions. In other areas, wheel tracks were not as defined and instead, some blocky fragments (e.g., 5-10 mm thick) of soil-like materials were displaced by the wheels. There were areas where small rocks (e.g., 1-3 cm) were pressed into weakly indurated or "crust" material. Soil and rock exposures are very different at Opportunity's landing site within a shallow 20 m crater at Meridiani. Outcrops of very fine-grained bedrock are found around the interior walls of the crater. The dominant soil unit within the crater is dark, fine-sand sized materials littered with larger spherules and spherule fragments (e.g., 1-10 mm); some of these spherules appear to be weathering out of the outcrop. A small-scale rippled soil unit seemingly lacking spherules located near the lowest part of the crater is probably a concentration of the fine-sand sized particles transported and partly reworked by wind. Assessment of initial rover tracks combined with observations of wheel slippage on sloping surfaces suggest that soil cohesion in the uppermost near subsurface material is low, and that finer particles (e.g., less than 30 microns) are also present along with the fine sand-sized particles. Additional investigations are underway to characterize rates of atmospheric dust deposition on the rovers, soil physical properties by trenching into targets of opportunity (e.g., soils, bedforms), surface

  8. Chromophore-modified antitumor anthracenediones: synthesis, DNA binding, and cytotoxic activity of 1,4-bis[(aminoalkyl)amino]benzo[g]-phthalazine-5,10-diones.

    PubMed

    Gandolfi, C A; Beggiolin, G; Menta, E; Palumbo, M; Sissi, C; Spinelli, S; Johnson, F

    1995-02-01

    As part of a program aimed at exploring the effect of the introduction of heteroatoms into the anthracene-9,10-dione chromophore, we have synthesized novel 1,4-bis[(aminoalkyl)amino]-benzo[g]phthalazine-5,10-diones (BPDs) 1 which are related to the antitumor agents ametantrone and mitoxantrone. Derivatives 1 were prepared by chromic acid oxidation of acylated benzo[g]phthalazines 5 followed by acid hydrolysis or by silylation-amination of 5,10-dihydroxybenzo[g]phthalazine-1,4-dione (8). The 1-[(aminoalkyl)amino]-4-amino congeners 2 were isolated in low yields as byproducts from the oxidation of 5. Against a panel of human tumor cell lines, the benzo[g]phthalazine-5,10-diones 1 and 2 exhibited cytotoxic activity comparable or even superior to that of mitoxantrone. In compounds 1, structure-activity relationships different than those operative in the carbocyclic series appeared to emerge. DNA-binding studies with the ametantrone-like compound 1c and its single-armed congener 2c indicated that the introduction of a 2,3-diaza subunit into the anthracene-9,10-dione chromophore reduces the affinity of the drug for DNA in comparison with ametantrone. On the other hand, the number of side-chain groups does not affect binding to a great extent. These findings seem to suggest mechanisms of cell death other than those induced by simple interaction of the 1,4-BPDs 1 and 2 with DNA.

  9. Bearing strength of lunar soil.

    NASA Technical Reports Server (NTRS)

    Jaffe, L. D.

    1971-01-01

    Bearing load vs penetration curves have been measured on a 1.3 g sample of lunar soil from the scoop of the Surveyor 3 soil mechanics surface sampler, using a circular indentor 2 mm in diameter. Measurements were made in an Earth laboratory, in air. This sample provided a unique opportunity to evaluate earlier, remotely controlled, in-situ measurements of lunar surface bearing properties. Bearing capacity, measured at a penetration equal to the indentor diameter, varied from 0.02-0.04 N/sq cm at bulk densities of 1.15 g/cu cm to 30-100 N/sq cm at 1.9 g/cu cm. Deformation was by compression directly below the indentor at bulk densities below 1.61 g/cu cm, by outward displacement at bulk densities over 1.62 g/cu cm. Preliminary comparison of in-situ remote measurements with those on returned material indicates good agreement if the lunar regolith at Surveyor 3 has a bulk density of 1.6 g/cu cm at 2.5 cm depth.

  10. Soil warming affects soil organic matter chemistry of all density fractions of a mountain forest soil

    NASA Astrophysics Data System (ADS)

    Schnecker, Jörg; Wanek, Wolfgang; Borken, Werner; Schindlbacher, Andreas

    2016-04-01

    Rising temperatures enhance microbial decomposition of soil organic matter (SOM) and increase thereby the soil CO2 efflux. Elevated microbial activity might differently affect distinct SOM pools, depending on their stability and accessibility. Soil fractions derived from density fractionation have been suggested to represent SOM pools with different turnover times and stability against microbial decomposition. We here investigated the chemical and isotopic composition of bulk soil and three different density fractions of forest soils from a long term warming experiment in the Austrian Alps. At the time of sampling the soils in this experiment had been warmed during the snow-free period for 8 consecutive years. During that time no thermal adaptation of the microbial community could be identified and CO2 release from the soil continued to be elevated by the warming treatment. Our results which included organic C content, total N content, δ13C, δ 14C, δ 15N and the chemical composition, identified by pyrolysis-GC/MS, showed no significant differences in bulk soil between warming treatment and control. The differences in the three individual fractions (free particulate organic matter, occluded particulate organic matter and mineral associated organic matter) were mostly small and the direction of warming induced change was variable with fraction and sampling depth. We did however find statistically significant effects of warming in all density fractions from 0-10 cm depth, 10-20 cm depth or both. Our results also including significant changes in the supposedly more stable mineral associated organic matter fraction where δ 13C values decreased at both sampling depths and the relative proportion of N-bearing compounds decreased at a sampling depth of 10-20 cm. All the observed changes can be attributed to an interplay of enhanced microbial decomposition of SOM and increased root litter input. This study suggests that soil warming destabilizes all density fractions of

  11. Remediating munitions contaminated soils

    SciTech Connect

    Shea, P.J.; Comfort, S.D.

    1995-10-01

    The former Nebraska Ordnance Plant (NOP) at Mead, NE was a military loading, assembling, and packing facility that produced bombs, boosters and shells during World War II and the Korean War (1942-1945, 1950-1956). Ordnances were loaded with 2,4,6-trinitrotoluene (TNT), amatol (TNT and NH{sub 4}NO{sub 3}), tritonal (TNT and Al) and Composition B (hexahydro-1,3,5-trinitro-1,3,5-triazine [RDX] and TNT). Process waste waters were discharged into wash pits and drainage ditches. Soils within and surrounding these areas are contaminated with TNT, RDX and related compounds. A continuous core to 300 cm depth obtained from an NOP drainage ditch revealed high concentrations of TNT in the soil profile and substantial amounts of monoamino reduction products, 4-amino-2,6-dinitrotoluene (4ADNT) and 2-amino-4,6-dinitrotoluene (2ADNT). Surface soil contained TNT in excess of 5000 mg kg{sup -1} and is believed to contain solid phase TNT. This is supported by measuring soil solution concentrations at various soil to solution ratios (1:2 to 1:9) and obtaining similar TNT concentrations (43 and 80 mg L{sup -1}). Remediating munitions-contaminated soil at the NOP and elsewhere is of vital interest since many of the contaminants are carcinogenic, mutagenic or otherwise toxic to humans and the environment. Incineration, the most demonstrated remediation technology for munitions-containing soils, is costly and often unacceptable to the public. Chemical and biological remediation offer potentially cost-effective and more environmentally acceptable alternatives. Our research objectives are to: (a) characterize the processes affecting the transport and fate of munitions in highly contaminated soil; (b) identify effective chemical and biological treatments to degrade and detoxify residues; and (c) integrate these approaches for effective and practical remediation of soil contaminated with TNT, RDX, and other munitions residues.

  12. Effects of composite soil with feldspathic sandstone and sand on soil aggregates and organic carbon

    NASA Astrophysics Data System (ADS)

    Li, J.; Han, J. C.; Zhang, Y.; Lei, G. Y.; Wang, H. Y.; Zhu, D. W.

    2016-08-01

    The case was to study the effects of soils with different proportions of feldspathic sandstone and sand on soil stability and organic carbon at 0-30 cm soil depth with four different ratios(C1, C2, C3 and C4), They were used to prepare the composite soil in Fu Ping, Shaanxi Province of China, then the soil aggregates distribution, WASR, MWD, GMD, D valueand and organic carbon content were measured and analysed.The results showed : the soil stability of C1, C2 and C3 was better than C4, i.e., the composition could improve the soil stability. With the increasing of the planting years, the contents of soil aggregates with the size >0.25 mm and MWD, GMD and SOC increased for each treatment at 0- 30 cm soil depth, which was contrary to D values. WASR of C2 was significantly higher than others (p<0.05) after 3-year planting. The significant logarithmic relationships were found between the D values and the ratios in C1, C2 and C3. Besides C1 and C2 could increase the stability and content of large soil aggregates to improve soil structure; C2 could significantly increase the SOC than others at 0- 30 cm soil depth.

  13. Formation of asteroids from mm-cm sized grains

    NASA Astrophysics Data System (ADS)

    Carrera, D.; Johansen, A.; Davies, M. B.

    2014-03-01

    Context. Asteroids and comets are intricately connected to life in the universe. Asteroids are the building blocks of terrestrial planets; water-rich asteroids and comets are likely to be the primary source of water for Earth's oceans and other volatiles (Morbidelli et al. 2000; Hartogh et al. 2011); and they may play role in mass extinctions. Yet, the formation of these objects is poorly understood. There is mounting evidence that the traditional picture of the formation of asteroids must be revised. The size distribution of asteroids is hard to reconcile with a traditional bottomup formation scenario. Instead, asteroids may form top-down, with large 100 - 1000 km sized objects forming first by the gravitational collapse of dense clumps of small particles. Experiments and simulations suggest that dust grains cannot grow to sizes larger than mm-cm in protoplanetary disks (Zsom et al. 2010). Also, primitive meteorites from the asteroid belt contain a large mass fraction in chondrules of sizes from 0.1 mm to a few mm. Hence, it is desirable to find a model for asteroid formation from mm-sized particles. Aims. In this work, we model the dynamics of mm-cm sized grains in dust-enriched inner regions of protoplanetary disks. We model the dust-gas interaction to determine whether dust grains of this size can form dense, self-gravitating clouds that can collapse to form asteroids. Methods. We perform shearing box simulations of the inner disk using the Pencil Code (Brandenburg & Dobler 2002). The simulations start with a Solar-type solids-to-gas ratio of 0.01 and we gradually increase the particle concentration. In a real protoplanetary disk, solid particles are expected to migrate from the outer regions and concentrate in the inner disk. Results. Our simulations show that mm-sized particles can form very dense clumps, driven by a run-away convergence in the radial-drift flow of these particles - this dynamic is known as the streaming instability (Youdin & Goodman 2005

  14. A 1.3 cm line survey toward Orion KL

    NASA Astrophysics Data System (ADS)

    Gong, Y.; Henkel, C.; Thorwirth, S.; Spezzano, S.; Menten, K. M.; Walmsley, C. M.; Wyrowski, F.; Mao, R. Q.; Klein, B.

    2015-09-01

    Context. The nearby Orion Kleinmann-Low nebula is one of the most prolific sources of molecular line emission. It has served as a benchmark for spectral line searches throughout the (sub)millimeter regime. Aims: The main goal is to systematically study the spectral characteristics of Orion KL in the λ ~ 1.3 cm band. Methods: We carried out a spectral line survey with the Effelsberg-100 m telescope toward Orion KL. It covers the frequency range between 17.9 GHz and 26.2 GHz, i.e., the radio "K band". We also examined ALMA maps to address the spatial origin of molecules detected by our 1.3 cm line survey. Results: In Orion KL, we find 261 spectral lines, yielding an average line density of about 32 spectral features per GHz above 3σ (a typical value of 3σ is 15 mJy). The identified lines include 164 radio recombination lines (RRLs) and 97 molecular lines. The RRLs, from hydrogen, helium, and carbon, stem from the ionized material of the Orion Nebula, part of which is covered by our beam. The molecular lines are assigned to 13 different molecular species including rare isotopologues. A total of 23 molecular transitions from species known to exist in Orion KL are detected for the first time in the interstellar medium. Non-metastable (J>K) 15NH3 transitions are detected in Orion KL for the first time. Based on the velocity information of detected lines and the ALMA images, the spatial origins of molecular emission are constrained and discussed. A narrow feature is found in SO2 (81,7 - 72,6), but not in other SO2 transitions, possibly suggesting the presence of a maser line. Column densities and fractional abundances relative to H2 are estimated for 12 molecules with local thermodynamic equilibrium (LTE) methods. Rotational diagrams of non-metastable 14NH3 transitions with J = K + 1 to J = K + 4 yield different results; metastable (J = K) 15NH3 is found to have a higher excitation temperature than non-metastable 15NH3, also indicating that they may trace different

  15. Seasonal Evolution of Titan's South Pole 220 cm-1 Cloud

    NASA Astrophysics Data System (ADS)

    Jennings, Donald

    2016-06-01

    A cloud of ices that had been seen only in Titan's north during winter began to emerge at the south pole in 2012. Discovered by Voyager IRIS as an emission feature at 220 cm-1, the cloud has been studied extensively in both the north and south by Cassini CIRS. The spectral feature acts as a tracer of the seasonal changes at Titan's poles, relating to evolving composition, temperature structure and dynamics. Although candidates have been proposed, the chemical makeup of the cloud has never been identified. The cloud is composed of condensates derived from gases created at high altitude and transported to the cold, shadowed pole. In the north the cloud has diminished gradually over the Cassini mission as Titan has transitioned from winter to spring. The southern cloud, on the other hand, grew rapidly after 2012. By late 2014 it had developed a complex ring structure that was confined to latitudes poleward of 70°S within the deep temperature well that had formed at the south pole [1]. The location of the cloud coincides in latitude with the HCN cloud reported by ISS and VIMS [2,3]. CIRS also saw enhanced gas emissions at those latitudes [4]. When it first formed, the cloud was abundant at altitudes as high as 250 km, while later it was found mostly at 100-150 km, suggesting that the material that had been deposited from above had gathered at the lower altitudes. Radiance from the southern cloud increased until mid-2015 and since then has decreased. The cloud may be transitioning to the more uniform hood morphology familiar in the north. Taking the north and south together, by the end of the Cassini mission in 2017 we will have observed almost an entire seasonal cycle of the ice cloud.

  16. Soil Property Influences on Xiphinema americanum Populations as Related to Maturity of Loess-Derived Soils.

    PubMed

    Schmitt, D P

    1973-10-01

    Field populations of Xiphinerna americanum around roots of Syringa vulgaris 'President Lincoln' were larger in Marshall silty clay loam, a medially developed loess soil, than in Monona silt loam, a minimally developed loess soil. Most X. amerieanum occurred in the top 15 cm of soil, with few below 30 cm. Maximum numbers occurred in August of both years in the Marshall soil, and in August 1969 and June 1970 in the Monona soil. Population fluctuations during the growing season were coincident with changes in soil moisture content. Although the population fluctuation pattern was the same at each depth tested, the adult-to-juvenile ratio increased in one soil while it decreased in the other. Numbers of X. americanum decreased as root weights decreased within a soil profile, but they were not correlated with root weights over all soils and depths. More X. americanum were recovered from the Marshall than from the Monona soil, but fibrous root weights were greater in the Monona soil. Survival of X. americanum in soil columns in growth chamber experiments was better in the Marshall than in the Monona soil. Movement and survival were different in identically textured Monona A and B horizon soils. Factors related to the ion exchange sites may affect X. americanum.

  17. Bacterial community structure and soil properties of a subarctic tundra soil in Council, Alaska.

    PubMed

    Kim, Hye Min; Jung, Ji Young; Yergeau, Etienne; Hwang, Chung Yeon; Hinzman, Larry; Nam, Sungjin; Hong, Soon Gyu; Kim, Ok-Sun; Chun, Jongsik; Lee, Yoo Kyung

    2014-08-01

    The subarctic region is highly responsive and vulnerable to climate change. Understanding the structure of subarctic soil microbial communities is essential for predicting the response of the subarctic soil environment to climate change. To determine the composition of the bacterial community and its relationship with soil properties, we investigated the bacterial community structure and properties of surface soil from the moist acidic tussock tundra in Council, Alaska. We collected 70 soil samples with 25-m intervals between sampling points from 0-10 cm to 10-20 cm depths. The bacterial community was analyzed by pyrosequencing of 16S rRNA genes, and the following soil properties were analyzed: soil moisture content (MC), pH, total carbon (TC), total nitrogen (TN), and inorganic nitrogen (NH4+ and NO3-). The community compositions of the two different depths showed that Alphaproteobacteria decreased with soil depth. Among the soil properties measured, soil pH was the most significant factor correlating with bacterial community in both upper and lower-layer soils. Bacterial community similarity based on jackknifed unweighted unifrac distance showed greater similarity across horizontal layers than through the vertical depth. This study showed that soil depth and pH were the most important soil properties determining bacterial community structure of the subarctic tundra soil in Council, Alaska.

  18. Soil organic carbon mining versus priming - controls of soil organic carbon stocks along a management gradient

    NASA Astrophysics Data System (ADS)

    Blanes, M. Carmen; Reinsch, Sabine; Glanville, Helen C.; Jones, Davey L.; Carreira, José A.; Pastrana, David N.; Emmett, Bridget A.

    2015-04-01

    Soil carbon (C), nitrogen (N) and phosphorous (P) are assumed to be connected stoichiometrically and C:N(:P) ratios are frequently used to interpret the soils nutrient status. However, plants are capable of initiating the supply of nutrients by releasing rhizodeposits into the soil, thereby stimulating soil organic matter decomposition mediated by the rhizosphere microbial community. To test the relative importance of the two mechanisms across a fertility gradient in the UK we carried out a laboratory experiment. Intact soil cores from two depths (0-15 cm and 85-100 cm) were incubated and C, N and P were added in all possible combinations resulting in a total of 216 soil cores. Soil respiration was measured (1 h incubation, 10 oC) nine times over a 2 week period. Preliminary results indicate that all soils were C limited at the surface as measured as increased soil CO2 efflux. N additions increased soil respiration only marginally, whereas C+N stimulated microbial activity on the surface, and was even more pronounced in the deeper soil layer. Belowground responses to C+P were small and even smaller for N+P but similar for both soil depths. Our results indicate nutrient controls on soil organic matter turnover differ not only across a management/fertility gradient but also vertically down the soil profile.

  19. Conserving Soil.

    ERIC Educational Resources Information Center

    Soil Conservation Service (USDA), Washington, DC.

    Designed as enrichment materials for grades six through nine, this program is an interdisciplinary study of soils. As part of the program students: (1) examine soil organisms; (2) research history of local Native Americans to see how they and others have used the land and its soils; (3) investigate how soils are degraded and how they are conserved…

  20. [Effects of soil surface mulching on solar greenhouse grafted and own-rooted cucumber growth and soil environment].

    PubMed

    Zhai, Sheng; Liang, Yinli; Wang, Juyuan

    2005-12-01

    The study on the effects of different soil surface mulching models, including wheat straw mulching (WS), plastic film mulching (PF), and wheat straw plus plastic film mulching (WP), on the growth of solar greenhouse grafted and own-rooted cucumber and on soil environment showed that soil surface mulching not only increased the individuals of pistillate flower, improved its differentiation and development, shortened fruit-developing period, increased fruit weight, reduced fruit malformation percentage, but also raised total yield. Among the test mulching models, WP was better than WS and PF, and the effects were superior on grafted than on own-rooted cucumber. Soil surface mulching also had considerable effects on soil environment, but the effects varied with different modules. For example, under field condition, the diurnal change of soil temperature was a single-peak curve, with its peak higher and appeared at 14:30 in 5 cm and 10 cm soil depth, but lower and appeared later in deeper soil layers. In this study, WS lowered the maximum soil temperature and raised the minimum soil temperature, making soil temperature quite stable, while PF raised the maximum soil temperature much higher and enhanced the minimum soil temperature less than WS and WP, making the largest variation range of soil temperature. WP played a role of raising soil temperature and kept it stable. Similar to the diurnal change of soil temperature at 5 cm and 10 cm depth, that of soil respiration rate was also a single-peak curve. The soil respiration rate in all treatmentg was significantly higher than that of CK, and WP had a higher soil respiration rate than PF and WS. There was a significant positive correlation between soil respiration rate and soil temperature at 5 cm and 10 cm depth. By the end of the experiment, soil bulk density at the depth of 0-20 cm was measured, which was significantly lower in WS and WP than in CK and PF. The difference in soil bulk density was gradually inconspicuous

  1. Early lung cancer detection project: Evaluation of 5, 10, 15, 20 tetrakis (4-carboxyphenyl) porphine (H{sub 2}TCPP). Final report

    SciTech Connect

    Tockman, M.S.

    1998-10-01

    The author evaluated a synthetic porphyrin, 5, 10, 15, 20 tetrakis (4-carboxyphenyl) porphene (H{sub 2}TCPP) as a marker of carcinogenesis. H{sub 2}TCPP was compared with two other carcinogenesis markers evaluated in the laboratory for their ability to detect exfoliated sputum cells undergoing transformation to lung cancer. In the present project the authors first established optimal conditions for cultured neoplastic and non-neoplastic (sputum) cells to take up H{sub 2}TCPP. This was accomplished using spectrofluorimetry and video-enhanced fluorescent microscopy to maximize H{sub 2}TCPP auto-fluorescence across a matrix of substrate conditions, including; reagent concentration, incubation time, temperature, and pH. The second aim was to validate H{sub 2}TCPP on clinical material obtained from subjects monitored in advance of clinical cancer and link those marker results with subsequent histologic confirmation of disease. This was accomplished by applying H{sub 2}TCPP to sputum specimens archived by the Frost Center at Johns Hopkins which maintains a record of the clinical course and long-term follow-up for the patients from whom the specimens were obtained. The authors have used fluorescent immunostaining and flow cytometry to compare uptake of these cytoplasmic Mabs to that of a potential new marker of carcinogenesis, 5, 10, 15, 20 tetrakis (4 carboxyphenyl) porphene (H{sub 2}TCPP). The nuclear uptake of H{sub 2}TCPP was compared to a standard quantitative fluorescent DNA marker (7-AAD).

  2. Photophysical Characterization and in Vitro Phototoxicity Evaluation of 5,10,15,20-Tetra(quinolin-2-yl)porphyrin as a Potential Sensitizer for Photodynamic Therapy.

    PubMed

    Costa, Letícia D; e Silva, Joana de A; Fonseca, Sofia M; Arranja, Cláudia T; Urbano, Ana M; Sobral, Abilio J F N

    2016-03-31

    Photodynamic therapy (PDT) is a selective and minimally invasive therapeutic approach, involving the combination of a light-sensitive compound, called a photosensitizer (PS), visible light and molecular oxygen. The interaction of these per se harmless agents results in the production of reactive species. This triggers a series of cellular events that culminate in the selective destruction of cancer cells, inside which the photosensitizer preferentially accumulates. The search for ideal PDT photosensitizers has been a very active field of research, with a special focus on porphyrins and porphyrin-related macrocycle molecules. The present study describes the photophysical characterization and in vitro phototoxicity evaluation of 5,10,15,20-tetra(quinolin-2-yl)porphyrin (2-TQP) as a potential PDT photosensitizer. Molar absorption coefficients were determined from the corresponding absorption spectrum, the fluorescence quantum yield was calculated using 5,10,15,20-tetraphenylporphyrin (TPP) as a standard and the quantum yield of singlet oxygen generation was determined by direct phosphorescence measurements. Toxicity evaluations (in the presence and absence of irradiation) were performed against HT29 colorectal adenocarcinoma cancer cells. The results from this preliminary study show that the hydrophobic 2-TQP fulfills several critical requirements for a good PDT photosensitizer, namely a high quantum yield of singlet oxygen generation (Φ∆ 0.62), absence of dark toxicity and significant in vitro phototoxicity for concentrations in the micromolar range.

  3. Effects of Heating on Proportions of Azaspiracids 1-10 in Mussels (Mytilus edulis) and Identification of Carboxylated Precursors for Azaspiracids 5, 10, 13, and 15.

    PubMed

    Kilcoyne, Jane; McCarron, Pearse; Hess, Philipp; Miles, Christopher O

    2015-12-30

    Azaspiracids (AZAs) are marine biotoxins that induce human illness following the consumption of contaminated shellfish. European Union regulation stipulates that only raw shellfish are tested, yet shellfish are often cooked prior to consumption. Analysis of raw and heat-treated mussels (Mytilus edulis) naturally contaminated with AZAs revealed significant differences (up to 4.6-fold) in AZA1-3 (1-3) and 6 (6) values due to heat-induced chemical conversions. Consistent with previous studies, high levels of 3 and 6 were detected in some samples that were otherwise below the limit of quantitation before heating. Relative to 1, in heat-treated mussels the average (n = 40) levels of 3 (range, 11-502%) and 6 (range, 3-170%) were 62 and 31%, respectively. AZA4 (4) (range, <1-27%), AZA5 (5) (range, 1-21%), and AZA8 (8) (range, 1-27%) were each ∼5%, whereas AZA7 (7), AZA9 (9), and AZA10 (10) (range, <1-8%) were each under 1.5%. Levels of 5, 10, AZA13 (13), and AZA15 (15) increased after heating, leading to the identification of novel carboxylated AZA precursors in raw shellfish extracts, which were shown by deuterium labeling to be precursors for 5, 10, 13, and 15.

  4. Fine (PM2.5), coarse (PM2.5-10), and metallic elements of suspended particulates for incense burning at Tzu Yun Yen temple in central Taiwan.

    PubMed

    Fang, Guor-Cheng; Chang, Cheng-Nan; Chu, Chia-Chium; Wu, Yuh-Shen; Pi-Cheng Fu, Peter; Chang, Shyh-Chyi; Yang, I-Lin

    2003-06-01

    Ambient suspended particulate concentrations were measured at Tzu Yun Yen temple (120 degrees, 34('), 10(") E; 24 degrees, 16('), 12(") N) in this study. This is representative of incense burning and semi-open sampling sites. The Universal-sampler collected fine and coarse particle material was used to measure suspended particulate concentrations, and sampling periods were from 16/08/2001 to 2/1/2002 at Tzu Yun Yen temple. In addition, metallic element concentrations, compositions of PM(2.5) and PM(2.5-10) for incense burning at Tzu Yun Yen temple were also analyzed in this study. The PM(2.5)/PM(10) ratios ranged between 31% and 87% and averaged 70+/-11% during incense the burning period, respectively. The median metallic element concentration order for these elements is Fe>Zn>Cr>Cd>Pb>Mn>Ni>Cu in fine particles (PM(2.5)) at the Tzu Yun Yen temple sampling site. The median metallic element concentration order for these elements is Fe>Zn>Cr>Pb>Cd>Ni>Mn>Cu in coarse particle (PM(2.5-10)) at the Tzu Yun Yen temple sampling site. Fine particulates (PM(2.5)) are the main portion of PM(10) at Tzu Yun Yen temple in this study. From the point of view of PM(10), these data reflect that the elements Fe, Zn, and Cr were the major elements distributed at Tzu Yun Yen temple in this study.

  5. The fingerprints of dioxin-like bromocarbazoles and chlorocarbazoles in selected forest soils in Germany.

    PubMed

    Mumbo, John; Pandelova, Marchela; Mertes, Florian; Henkelmann, Bernhard; Bussian, Bernd M; Schramm, Karl-Werner

    2016-11-01

    The occurrence of bromocarbazoles and chlorocarbazoles was studied in 86 forest soil samples from different regions in Germany. Carbazole, 3-chlorocarbazole, 3-bromocarbazole and 3,6-dibromocarbazole were qualitatively detected in the humic layer of 59 soil samples with bromocarbazoles reported here for the first time in soil. Furthermore, the halogenated carbazoles, PCDD/Fs and PCBs were detected in the humic and mineral soil horizons (0-5 cm and 5-10 cm) of a subset of 11 soil samples subjected to quantitative analysis. Concentrations ranged from 0.6 to 267.6 ng/g (carbazole); 0.2-7.2 ng/g (3-bromocarbazole); 0.0-9.1 ng/g (3-chlorocarbazole); 0.2-19.8 ng/g (3,6-dibromocarbazole); 0.4-67.6 ng/g (3,6-dichlorocarbazole); 0.0-0.7 ng/g (PCDDs); 0.0-0.3 ng/g (PCDFs) and 0.0-33.7 ng/g (PCBs). Concentrations decreased with depth and correlated positively to total organic carbon (TOC). When it was based on TOC%, an increase in concentration with depth was observed in most soil samples. With respect to dioxin-like toxicity, 3-bromocarbazole, 3-chlorocarbazole, 3,6-dibromocarbazole and 3,6-dichlorocarbazoles caused induction of CYP1A1-dependent EROD activity in HII4E rat hepatoma cell line. Their relative effect potency after 72 h exposure ranged from 0.00005 to 0.00013 and was directly related to the degree of halogenation with 2,3,7,8-tetrachlorodibenzo-p-dioxin as reference. Furthermore, their contribution to overall soil dioxin-like toxicity was not significant in comparison to PCDD/Fs and PCBs though the sum toxic equivalency was limited to three halogenated carbazole congeners. Bromocarbazoles and chlorocarbazoles are emerging dioxin-like toxic environmental contaminants with potential for wide distribution occurring simultaneously with PCDD/Fs and PCBs. PMID:27479457

  6. Electrical methods of determining soil moisture content

    NASA Technical Reports Server (NTRS)

    Silva, L. F.; Schultz, F. V.; Zalusky, J. T.

    1975-01-01

    The electrical permittivity of soils is a useful indicator of soil moisture content. Two methods of determining the permittivity profile in soils are examined. A method due to Becher is found to be inapplicable to this situation. A method of Slichter, however, appears to be feasible. The results of Slichter's method are extended to the proposal of an instrument design that could measure available soil moisture profile (percent available soil moisture as a function of depth) from a surface measurement to an expected resolution of 10 to 20 cm.

  7. Effect of different mulch materials on the soil dehydrogenase activity (DHA) in an organic pepper crop

    NASA Astrophysics Data System (ADS)

    Moreno, Marta M.; Peco, Jesús; Campos, Juan; Villena, Jaime; González, Sara; Moreno, Carmen

    2016-04-01

    The use biodegradable materials (biopolymers of different composition and papers) as an alternative to conventional mulches has increased considerably during the last years mainly for environmental reason. In order to assess the effect of these materials on the soil microbial activity during the season of a pepper crop organically grown in Central Spain, the soil dehydrogenase activity (DHA) was measured in laboratory. The mulch materials tested were: 1) black polyethylene (PE, 15 μm); black biopolymers (15 μm): 2) Mater-Bi® (corn starch based), 3) Sphere 4® (potato starch based), 4) Sphere 6® (potato starch based), 5) Bioflex® (polylactic acid based), 6) Ecovio® (polylactic acid based), 7) Mimgreen® (black paper, 85 g/m2). A randomized complete block design with four replications was adopted. The crop was drip irrigated following the water demand of each treatment. Soil samples (5-10 cm depth) under the different mulches were taken at different dates (at the beginning of the crop cycle and at different dates throughout the crop season). Additionally, samples of bare soil in a manual weeding and in an untreated control were taken. The results obtained show the negative effect of black PE on the DHA activity, mainly as result of the higher temperature reached under the mulch and the reduction in the gas interchange between the soil and the atmosphere. The values corresponding to the biodegradable materials were variable, although highlighting the low DHA activity observed under Bioflex®. In general, the uncovered treatments showed higher values than those reached under mulches, especially in the untreated control. Keywords: mulch, biodegradable, biopolymer, paper, dehydrogenase activity (DHA). Acknowledgements: the research was funded by Project RTA2011-00104-C04-03 from the INIA (Spanish Ministry of Economy and Competitiveness).

  8. Measuring Soil Hydraulic Conductivity With Microwaves

    NASA Technical Reports Server (NTRS)

    Blanchard, B. J.; Oneill, P. E.

    1985-01-01

    Soil mapping for large or small areas done rapidly. Technique requires simple radiometric measurements of L-band (15 to 30 cm) and thermal infrared emissions from ground within 2 days after saturation of surface. Technique based on observation that correlation exists between L-band emissivity and hydraulic conductivity of soil.

  9. Passive microwave soil moisture research

    NASA Technical Reports Server (NTRS)

    Schmugge, T.; Oneill, P. E.; Wang, J. R.

    1986-01-01

    During the four years of the AgRISTARS Program, significant progress was made in quantifying the capabilities of microwave sensors for the remote sensing of soil moisture. In this paper, a discussion is provided of the results of numerous field and aircraft experiments, analysis of spacecraft data, and modeling activities which examined the various noise factors such as roughness and vegetation that affect the interpretability of microwave emission measurements. While determining that a 21-cm wavelength radiometer was the best single sensor for soil moisture research, these studies demonstrated that a multisensor approach will provide more accurate soil moisture information for a wider range of naturally occurring conditions.

  10. PVA/CM-chitosan/honey hydrogels prepared by using the combined technique of irradiation followed by freeze-thawing

    NASA Astrophysics Data System (ADS)

    Afshari, M. J.; Sheikh, N.; Afarideh, H.

    2015-08-01

    Hydrogels with three components, poly(vinyl alcohol) (PVA), carboxymethylate chitosan (CM-chitosan) and honey have been prepared by using radiation method and radiation followed by freeze-thawing cycles technique (combinational method). The solid concentration of the polymer solution is 15 wt% and the ratios of PVA/CM-chitosan/honey are 10/1.5/3.5, 10/2/3, 10/3/2, and 10/3.5/1.5. The applied irradiation doses are 25, 30 and 40 kGy. Various tests have been done to evaluate the hydrogel properties to produce materials to be used as wound dressing. The results show that combinational method improves the mechanical strength of hydrogels while it has no significant effect on the water evaporation rate of gels. The combinational method decreases the swelling of hydrogels significantly, albeit this parameter is still acceptable for wound dressing. Microbiological analyses show that the hydrogel prepared by both methods can protect the wound from Escherichia coli bacterial infection. The wound healing test shows the good performance of the gels in mice.

  11. Phosphorus Release to Floodwater from Calcareous Surface Soils and Their Corresponding Subsurface Soils under Anaerobic Conditions.

    PubMed

    Jayarathne, P D K D; Kumaragamage, D; Indraratne, S; Flaten, D; Goltz, D

    2016-07-01

    Enhanced phosphorus (P) release from soils to overlying water under flooded, anaerobic conditions has been well documented for noncalcareous and surface soils, but little information is available for calcareous and subsurface soils. We compared the magnitude of P released from 12 calcareous surface soils and corresponding subsurface soils to overlying water under flooded, anaerobic conditions and examined the reasons for the differences. Surface (0-15 cm) and subsurface (15-30 cm) soils were packed into vessels and flooded for 8 wk. Soil redox potential and concentrations of dissolved reactive phosphorus (DRP) and total dissolved Ca, Mg, Fe, and Mn in floodwater and pore water were measured weekly. Soil test P was significantly smaller in subsurface soils than in corresponding surface soils; thus, the P release to floodwater from subsurface soils was significantly less than from corresponding surface soils. Under anaerobic conditions, floodwater DRP concentration significantly increased in >80% of calcareous surface soils and in about 40% of subsurface soils. The increase in floodwater DRP concentration was 2- to 17-fold in surface soils but only 4- to 7-fold in subsurface soils. With time of flooding, molar ratios of Ca/P and Mg/P in floodwater increased, whereas Fe/P and Mn/P decreased, suggesting that resorption and/or reprecipitation of P took place involving Fe and Mn. Results indicate that P release to floodwater under anaerobic conditions was enhanced in most calcareous soils. Surface and subsurface calcareous soils in general behaved similarly in releasing P under flooded, anaerobic conditions, with concentrations released mainly governed by initial soil P concentrations. PMID:27380087

  12. Experimental shock metamorphism of the Murchison CM carbonaceous chondrite

    NASA Astrophysics Data System (ADS)

    Tomeoka, Kazushige; Yamahana, Yasuhiro; Sekine, Toshimori

    1999-11-01

    A series of shock-recovery experiments were carried out on the Murchison CM carbonaceous chondrite by using a single-stage propellant gun. The Murchison samples were shocked in nine experiments at peak pressures from 4 to 49 GPa. The recovered samples were studied in detail by using an optical microscope, a scanning electron microscope and an electron-probe microanalyzer. Chondrules are flattened in the plane of the shock front at 4 to 30 GPa. The mean aspect ratio of chondrules increases from 1.17 to 1.57 roughly in proportion to the intensity of shock pressure up to ˜25 GPa. At 25 to 30 GPa, the mean aspect ratio does not increase further, and chondrules show increasingly more random orientations and degrade their preferred orientations, and at ˜35 GPa, they are extensively disrupted. Most coarse grains of olivine and pyroxene are irregularly fractured, fracture density increases with increasing shock pressure and at ˜30 GPa almost all are thoroughly fractured with subgrains of <1 to 5 μm in size. At ˜20 GPa, subparallel fractures begin to form in the matrix in directions roughly perpendicular to the compression axis and their densities increase with pressure, especially dramatically at 25 to 30 GPa; thus, the sample is increasingly comminuted and becomes fragile. Local shock melting occurs as melt veins and pockets at 20 to 30 GPa. Fracture-filling veins of fine grains of matrix are also produced at 25 to 30 GPa. The melts and the fine grains seem to result mainly from frictional heating due to displacement along fractures. At ˜35 GPa, melting occurs pervasively throughout the matrix. The melts are mainly produced from the matrix; however, they are consistently more enriched in Fe, S, and Ca, which indicates that these elements are selectively incorporated into the melts. The melts contain tiny spherules of Fe-Ni metal, Fe sulfide, and numerous vesicles. At 49 GPa, the matrix is totally melted and coarse grains of olivine are partially melted. The melts

  13. Analysis of PM10, PM2.5, and PM2 5-10 concentrations in Santiago, Chile, from 1989 to 2001.

    PubMed

    Koutrakis, Petros; Sax, Sonja N; Sarnat, Jeremy A; Coull, Brent; Demokritou, Phil; Oyola, Pedro; Garcia, Javier; Gramsch, Ernesto

    2005-03-01

    Daily particle samples were collected in Santiago, Chile, at four urban locations from January 1, 1989, through December 31, 2001. Both fine PM with da < 2.5 microm (PM2.5) and coarse PM with 2.5 < da < 10 microm (PM2.5-10) were collected using dichotomous samplers. The inhalable particle fraction, PM10, was determined as the sum of fine and coarse concentrations. Wind speed, temperature and relative humidity (RH) were also measured continuously. Average concentrations of PM2.5 for the 1989-2001 period ranged from 38.5 microg/m3 to 53 microg/m3. For PM2.5-10 levels ranged from 35.8-48.2 microg/m3 and for PM10 results were 74.4-101.2 microg/m3 across the four sites. Both annual and daily PM2.5 and PM10 concentration levels exceeded the U.S. National Ambient Air Quality Standards and the European Union concentration limits. Mean PM2.5 levels during the cold season (April through September) were more than twice as high as those observed in the warm season (October through March); whereas coarse particle levels were similar in both seasons. PM concentration trends were investigated using regression models, controlling for site, weekday, month, wind speed, temperature, and RH. Results showed that PM2.5 concentrations decreased substantially, 52% over the 12-year period (1989-2000), whereas PM2.5-10 concentrations increased by approximately 50% in the first 5 years and then decreased by a similar percentage over the following 7 years. These decreases were evident even after controlling for significant climatic effects. These results suggest that the pollution reduction programs developed and implemented by the Comisión Nacional del Medio Ambiente (CONAMA) have been effective in reducing particle levels in the Santiago Metropolitan region. However, particle levels remain high and it is thus imperative that efforts to improve air quality continue.

  14. Cytotoxicity of PM(2.5) and PM(2.5--10) ambient air pollutants assessed by the MTT and the Comet assays.

    PubMed

    Hsiao, W L; Mo, Z Y; Fang, M; Shi, X M; Wang, F

    2000-11-20

    Ambient air particulate matters are classified into two distinct modes in size distribution, namely the coarse and fine particles. Correlation between high particulate concentration and adverse effects on human populations has long been recognized, however, the toxicology of these adverse effects has not been clarified. In the current report, the cytotoxic effects of the solvent-extractable organic compounds (SEOC) from fine particles smaller than 2.5 microm (PM(2.5)) and from coarse particles between 2.5-10 microm (PM(2.5-10)) were studied. Nine 24h consecutive monthly samples were tested to determine the correlation between cytotoxicity and total SEOC in two size fractions of particulate air pollution. Cytotoxicity of SEOC was measured by two micro-scale mammalian cells-based bioassays: the MTT cell proliferation assay, and the Comet assay for the detection of DNA damage. A well-defined mammalian cell line - Rat 6 rodent fibroblast was employed in the study. The SEOC extracts of air particulate matters were sub divided into two equal parts. One part was dissolved in DMSO, the other in KOH/hexane and then conjugated with bovine serum albumin to produce a lipid-soluble fraction for testing. The DMSO fraction would contain mainly the polycyclic aromatic hydrocarbons (PAH), alkanes and alkanols, while the lipid-soluble fraction would be enriched with fatty acids. The results from MTT assay showed that cytotoxicity of the PM(2.5) was much more severe than the PM(2.5-10), suggesting that toxic SEOC were confined to the fine particles. By and large, the DMSO solubles were much more toxic than the lipid solubles. The degree of cytotoxicity of the DMSO soluble samples is positively correlated to the amount of particulates present in the ambient air. For the PM(2.5), the winter samples were significantly more toxic than the summer samples in terms of cell killing, which seemed to be a direct reflection of the total loading of organic matter in the samples. Results from

  15. Efficacy of 1,3-Dichloropropene in Soil Amended with Compost and Unamended Soil

    PubMed Central

    Riegel, C.; Nelson, S. D.; Dickson, D. W.; Allen, L. H.; Peterson, L. G.

    2001-01-01

    1,3-Dichloropropene (1,3-D) is a likely alternative soil fumigant for methyl bromide. The objective was to determine root-knot nematode, Meloidogyne incognita, survival in microplots after exposure to 1,3-D for various periods of time in soil that have previously been amended with compost. The treatments were 1,3-D applied broadcast at 112 liters/ha and untreated controls in both compost-amended and unamended soil. Soil samples were collected from each microplot at 6, 24, 48, 72, and 96 hours after fumigation at three depths (0-15, 15-30, and 30-45 cm). One week after fumigation, six tomato seedlings were transplanted into each microplot and root galling was recorded 6 weeks later. Plants grown in fumigated compost-amended soil had more galls than plants from fumigated unamended soil at P ≤ 0.1. Gall indices from roots in fumigated soil amended with compost were not different from nonfumigated controls. Based on soil bioassays, the number of galls decreased with increasing time after fumigation in both compost-amended and unamended soil at 0-to-15 and 15-to-30 cm depths, but not at 30 to 45 cm deep. Higher soil water content due to the elevated levels of organic matter in the soil at these depths may have interfered with 1,3-D movement, thus reducing its efficacy. PMID:19265889

  16. The effect of soil on cork quality.

    PubMed

    Pestana, Miguel N; Gomes, Alberto A

    2014-01-01

    The present work aimed to contribute for a better knowledge regarding soil features as cork quality indicators for stoppers. Cork sampling was made in eight Cork oak stands (montados de sobreiro) located in the Plio-Plistocene sedimentary formations of Península de Setúbal in southern Tagus River region. The samples used to classify the cork as stopper for wine bottles were obtained in eight cork oak stands, covering soils of different types of sandstones of the Plio-plistocene. In each stand, we randomly chose five circular plots with 30 m radius and five trees per plot with same stripping conditions determined by: dendrometric features (HD- height stipping, PBH- perimeter at breaster height), trees vegetative condition (defoliation degree); stand features (density, percentage canopy cover); site conditions (soil type and orientation). In the center of each plot a pit was open to characterize the soil profile and to classify the soil. Cork quality for stoppers was evaluated according to porosity, pores/per cm(2) and cork boards thickness. The soil was characterized according to morphological soil profile features (lithology, soil profound, and soil horizons) and chemical soil surface horizon features (organic matter, pH, macro, and micronutrients availability). Based on the variables studied and using the numerical taxonomy, we settled relationships between the cork quality and some soil features. The results indicate: (1) high correlation between the cork caliber and boron, cation exchange capacity, total nitrogen, exchange acidity, and exchangeable magnesium, potassium, calcium, and sodium in soils of theirs cork oaks; (2) the cork porosity is correlated with the number of pores/cm(2) and magnesium soil content; (3) the other soil features have a lower correlation with the caliber, porosity, and the number of pores per cm(2). PMID:25353015

  17. The effect of soil on cork quality

    PubMed Central

    Pestana, Miguel N.; Gomes, Alberto A.

    2014-01-01

    The present work aimed to contribute for a better knowledge regarding soil features as cork quality indicators for stoppers. Cork sampling was made in eight Cork oak stands (montados de sobreiro) located in the Plio-Plistocene sedimentary formations of Península de Setúbal in southern Tagus River region. The samples used to classify the cork as stopper for wine bottles were obtained in eight cork oak stands, covering soils of different types of sandstones of the Plio-plistocene. In each stand, we randomly chose five circular plots with 30 m radius and five trees per plot with same stripping conditions determined by: dendrometric features (HD- height stipping, PBH- perimeter at breaster height), trees vegetative condition (defoliation degree); stand features (density, percentage canopy cover); site conditions (soil type and orientation). In the center of each plot a pit was open to characterize the soil profile and to classify the soil. Cork quality for stoppers was evaluated according to porosity, pores/per cm2 and cork boards thickness. The soil was characterized according to morphological soil profile features (lithology, soil profound, and soil horizons) and chemical soil surface horizon features (organic matter, pH, macro, and micronutrients availability). Based on the variables studied and using the numerical taxonomy, we settled relationships between the cork quality and some soil features. The results indicate: (1) high correlation between the cork caliber and boron, cation exchange capacity, total nitrogen, exchange acidity, and exchangeable magnesium, potassium, calcium, and sodium in soils of theirs cork oaks; (2) the cork porosity is correlated with the number of pores/cm2 and magnesium soil content; (3) the other soil features have a lower correlation with the caliber, porosity, and the number of pores per cm2. PMID:25353015

  18. The effect of soil on cork quality.

    PubMed

    Pestana, Miguel N; Gomes, Alberto A

    2014-01-01

    The present work aimed to contribute for a better knowledge regarding soil features as cork quality indicators for stoppers. Cork sampling was made in eight Cork oak stands (montados de sobreiro) located in the Plio-Plistocene sedimentary formations of Península de Setúbal in southern Tagus River region. The samples used to classify the cork as stopper for wine bottles were obtained in eight cork oak stands, covering soils of different types of sandstones of the Plio-plistocene. In each stand, we randomly chose five circular plots with 30 m radius and five trees per plot with same stripping conditions determined by: dendrometric features (HD- height stipping, PBH- perimeter at breaster height), trees vegetative condition (defoliation degree); stand features (density, percentage canopy cover); site conditions (soil type and orientation). In the center of each plot a pit was open to characterize the soil profile and to classify the soil. Cork quality for stoppers was evaluated according to porosity, pores/per cm(2) and cork boards thickness. The soil was characterized according to morphological soil profile features (lithology, soil profound, and soil horizons) and chemical soil surface horizon features (organic matter, pH, macro, and micronutrients availability). Based on the variables studied and using the numerical taxonomy, we settled relationships between the cork quality and some soil features. The results indicate: (1) high correlation between the cork caliber and boron, cation exchange capacity, total nitrogen, exchange acidity, and exchangeable magnesium, potassium, calcium, and sodium in soils of theirs cork oaks; (2) the cork porosity is correlated with the number of pores/cm(2) and magnesium soil content; (3) the other soil features have a lower correlation with the caliber, porosity, and the number of pores per cm(2).

  19. A simple model of carbon in the soil profile for agricultural soils in Northwestern Europe

    NASA Astrophysics Data System (ADS)

    Taghizadeh-Toosi, Arezoo; Hutchings, Nicholas J.; Vejlin, Jonas; Christensen, Bent T.; Olesen, Jørgen E.

    2014-05-01

    World soil carbon (C) stocks are second to those in the ocean, and represent three times as much C as currently present in the atmosphere. The amount of C in soil may play a significant role in carbon exchanges between the atmosphere and the terrestrial environment. The C-TOOL model is a three-pool linked soil organic carbon (SOC) model in well-drained mineral soils under agricultural land management to allow generalized parameterization for estimating effects of management measures at medium to long time scales for the entire soil profile (0-100 cm). C-TOOL has been developed to enable simulations of SOC turnover in soil using temperature dependent first order kinetics for describing decomposition. Compared with many other SOC models, C-TOOL applies a less complicated structure, which facilitates easier calibration, and it requires only few inputs (i.e., average monthly air temperature, soil clay content,soil carbon-to-nitrogen ratio, and C inputs to the soil from plants and other sources). C-TOOL was parameterized using SOC and radiocarbon data from selected long-term field treatments in United Kingdom, Sweden and Denmark. However, less data were available for evaluation of subsoil C (25-100 cm) from the long-term experiments applied. In Denmark a national 7×7 km grid net was established in 1986 for soil C monitoring down to 100 cm depth. The results of SOC showed a significant decline from 1997 to 2009 in the 0-50 cm soil layer. This was mainly attributed to changes in the 25-50 cm layer, where a decline in SOC was found for all soil texture types. Across the period 1986 to 2009 there was clear tendency for increasing SOC on the sandy soils and reductions on the loamy soils. This effect is linked to land use, since grasslands and dairy farms are more abundant in the western parts of Denmark, where most of the sandy soils are located. The results and the data from soil monitoring have been used to validate the C-TOOL modelling approach used for accounting of

  20. Soil experiment

    NASA Technical Reports Server (NTRS)

    Hutcheson, Linton; Butler, Todd; Smith, Mike; Cline, Charles; Scruggs, Steve; Zakhia, Nadim

    1987-01-01

    An experimental procedure was devised to investigate the effects of the lunar environment on the physical properties of simulated lunar soil. The test equipment and materials used consisted of a vacuum chamber, direct shear tester, static penetrometer, and fine grained basalt as the simulant. The vacuum chamber provides a medium for applying the environmental conditions to the soil experiment with the exception of gravity. The shear strength parameters are determined by the direct shear test. Strength parameters and the resistance of soil penetration by static loading will be investigated by the use of a static cone penetrometer. In order to conduct a soil experiment without going to the moon, a suitable lunar simulant must be selected. This simulant must resemble lunar soil in both composition and particle size. The soil that most resembles actual lunar soil is basalt. The soil parameters, as determined by the testing apparatus, will be used as design criteria for lunar soil engagement equipment.

  1. Effect of Thickness of a Water Repellent Soil Layer on Soil Evaporation Rate

    NASA Astrophysics Data System (ADS)

    Ahn, S.; Im, S.; Doerr, S.

    2012-04-01

    A water repellent soil layer overlying wettable soil is known to affect soil evaporation. This effect can be beneficial for water conservation in areas where water is scarce. Little is known, however, about the effect of the thickness of the water repellent layer. The thickness of this layer can vary widely, and particularly after wildfire, with the soil temperature reached and the duration of the fire. This study was conducted to investigate the effect of thickness of a top layer of water repellent soil on soil evaporation rate. In order to isolate the thickness from other possible factors, fully wettable standard sand (300~600 microns) was used. Extreme water repellency (WDPT > 24 hours) was generated by 'baking' the sand mixed with oven-dried pine needles (fresh needles of Pinus densiflora) at the mass ratio of 1:13 (needle:soil) at 185°C for 18 hours. The thicknesses of water repellent layers were 1, 2, 3 and 7 cm on top of wettable soil. Fully wettable soil columns were prepared as a control. Soil columns (8 cm diameter, 10 cm height) were covered with nylon mesh. Tap water (50 ml, saturating 3 cm of a soil column) was injected with hypoderm syringes from three different directions at the bottom level. The injection holes were sealed with hot-melt adhesive immediately after injection. The rate of soil evaporation through the soil surface was measured by weight change under isothermal condition of 40°C. Five replications were made for each. A trend of negative correlation between the thickness of water repellent top layer and soil evaporation rate is discussed in this contribution.

  2. Imidacloprid movement in soils and impacts on soil microarthropods in southern Appalachian eastern hemlock stands.

    PubMed

    Knoepp, Jennifer D; Vose, James M; Michael, Jerry L; Reynolds, Barbara C

    2012-01-01

    Imidacloprid is a systemic insecticide effective in controlling the exotic pest (hemlock woolly adelgid) in eastern hemlock () trees. Concerns over imidacloprid impacts on nontarget species have limited its application in southern Appalachian ecosystems. We quantified the movement and adsorption of imidacloprid in forest soils after soil injection in two sites at Coweeta Hydrologic Laboratory in western North Carolina. Soils differed in profile depth, total carbon and nitrogen content, and effective cation exchange capacity. We injected imidacloprid 5 cm into mineral soil, 1.5 m from infested trees, using a Kioritz soil injector. We tracked the horizontal and vertical movement of imidacloprid by collecting soil solution and soil samples at 1 m, 2 m, and at the drip line from each tree periodically for 1 yr. Soil solution was collected 20 cm below the surface and just above the saprolite, and acetonitrile-extractable imidacloprid was determined through the profile. Soil solution and extractable imidacloprid concentrations were determined by high-performance liquid chromatography. Soil solution and extractable imidacloprid concentrations were greater in the site with greater soil organic matter. Imidacloprid moved vertically and horizontally in both sites; concentrations generally declined downward in the soil profile, but preferential flow paths allowed rapid vertical movement. Horizontal movement was limited, and imidacloprid did not move to the tree drip line. We found a negative relationship between adsorbed imidacloprid concentrations and soil microarthropod populations largely in the low-organic-matter site; however, population counts were similar to other studies at Coweeta. PMID:22370410

  3. Glass Forming Ability and Kinetic Characters of Paramagnetic Nd60Co40-xAlx(x=5, 10, 15) Bulk Metallic Glasses

    NASA Astrophysics Data System (ADS)

    Xia, L.; Dong, Y. D.

    Paramagnetic Nd60Co40-xAlx(x=5, 10, 15) bulk metallic glasses (BMGs) were prepared in the shape of rods 2 mm in diameter by suction casting. The ternary alloys have shown distinct glass transitions in Differential Scanning Calorimetry (DSC) measurements and excellent glass-forming ability. The glass transition and crystallization behaviors as well as their kinetics have been studied. The reduced glass transition temperature and the supercooled liquid region of the alloys were found to increase with the increasing content of Al. The role of Al was discussed. The parameter γ defined by Liu et al. was employed to discuss the glass-forming ability of the alloys and the critical cooling rates as well as the critical section thickness of the alloys were predicted accordingly.

  4. Comparison between 5,10,15,20-tetraaryl- and 5,15-diarylporphyrins as photosensitizers: synthesis, photodynamic activity, and quantitative structure-activity relationship modeling.

    PubMed

    Banfi, Stefano; Caruso, Enrico; Buccafurni, Loredana; Murano, Roberto; Monti, Elena; Gariboldi, Marzia; Papa, Ester; Gramatica, Paola

    2006-06-01

    The synthesis of a panel of seven nonsymmetric 5,10,15,20-tetraarylporphyrins, 13 symmetric and nonsymmetric 5,15-diarylporphyrins, and one 5,15-diarylchlorin is described. In vitro photodynamic activities on HCT116 human colon adenocarcinoma cells were evaluated by standard cytotoxicity assays. A predictive quantitative structure-activity relationship (QSAR) regression model, based on theoretical holistic molecular descriptors, of a series of 34 tetrapyrrolic photosensitizers (PSs), including the 24 compounds synthesized in this work, was developed to describe the relationship between structural features and photodynamic activity. The present study demonstrates that structural features significantly influence the photodynamic activity of tetrapyrrolic derivatives: diaryl compounds were more active with respect to the tetraarylporphyrins, and among the diaryl derivatives, hydroxy-substituted compounds were more effective than the corresponding methoxy-substituted ones. Furthermore, three monoarylporphyrins, isolated as byproducts during diarylporphyrin synthesis, were considered for both photodynamic and QSAR studies; surprisingly they were found to be particularly active photosensitizers.

  5. 5,10-Methylenetetrahydrofolate reductase polymorphisms and pharmacogenetics: a new role of single nucleotide polymorphisms in the folate metabolic pathway in human health and disease.

    PubMed

    Kim, Young-In

    2005-11-01

    Knowledge about the role of folate, a water-soluble B vitamin, and single nucleotide polymorphisms (SNPs) in the folate metabolic pathway in human health and disease has been rapidly expanding. Recently, functionally significant SNPs in 5,10-methylenetetrahydrofolate reductase (MTHFR), a critical enzyme for intracellular folate homeostasis and metabolism, have been identified and characterized. An emerging body of in vitro and clinical evidence suggests that these MTHFR SNPs may be an important pharmacogenetic determinant of predicting response to and toxicity of methotrexate and 5-fluorouracil-based cancer and anti-inflammatory treatments because of their well-defined and highly relevant biochemical effects on intracellular folate composition and one-carbon transfer reactions.

  6. Photodynamic antimicrobial chemotherapy activity of (5,10,15,20-tetrakis(4-(4-carboxyphenycarbonoimidoyl)phenyl)porphyrinato) chloro gallium(III).

    PubMed

    Managa, Muthumuni; Amuhaya, Edith K; Nyokong, Tebello

    2015-12-01

    (5,10,15,20-Tetrakis(4-(4-carboxyphenycarbonoimidoyl)phenyl)porphyrinato) chloro gallium(III) (complex 1) was conjugated to platinum nanoparticles (PtNPs) (represented as 1-PtNPs). The resulting conjugate showed 18 nm red shift in the Soret band when compared to 1 alone. Complex 1 and 1-PtNPs showed promising photodynamic antimicrobial chemotherapy (PACT) activity against Staphylococcus aureus, Escherichia coli and Candida albicans in solution where the log reductions obtained were 4.92, 3.76, and 3.95, respectively for 1-PtNPs. The singlet oxygen quantum yields obtained were higher at 0.56 for 1-PtNPs in DMF while that of 1 was 0.52 in the same solvent. This resulted in improved PACT activity for 1-PtNPs compared to 1 alone.

  7. Oxyfunctionalization of unactivated C-H bonds in triterpenoids with tert-butylhydroperoxide catalyzed by meso-5,10,15,20-tetramesitylporphyrinate osmium(II) carbonyl complex.

    PubMed

    Ogawa, Shoujiro; Wakatsuki, Yasuo; Makino, Mitsuko; Fujimoto, Yasuo; Yasukawa, Ken; Kikuchi, Takashi; Ukiya, Motohiko; Akihisa, Toshihiro; Iida, Takashi

    2010-02-01

    A system consisting of meso-5,10,15,20-tetramesitylporphyrinate osmium(II) carbonyl complex [Os(TMP)CO] as a precatalyst and tert-butylhydroperoxide (TBHP) as an oxygen donor is shown to be an efficient, regioselective oxidant system for the allylic oxidation, ketonization and hydroxylation of unactivated C-H bonds in a series of the peracetate derivatives of penta- and tetracyclic triterpenoids. Treatment of the substrates with this oxidant system afforded a variety of novel or scarce oxygenated derivatives in one-step. Structures of the isolated components, after chromatographic separation, were determined by spectroscopic methods including GC-MS and shift-correlated 2D-NMR techniques. Factors governing the regioselectivity and the possible mechanism for the oxyfunctionalization of the unactivated carbons are also discussed.

  8. An in vitro enzymatic assay to measure transcription inhibition by gallium(III) and H3 5,10,15-tris(pentafluorophenyl)corroles.

    PubMed

    Tang, Grace Y; Pribisko, Melanie A; Henning, Ryan K; Lim, Punnajit; Termini, John; Gray, Harry B; Grubbs, Robert H

    2015-03-18

    Chemotherapy often involves broad-spectrum cytotoxic agents with many side effects and limited targeting. Corroles are a class of tetrapyrrolic macrocycles that exhibit differential cytostatic and cytotoxic properties in specific cell lines, depending on the identities of the chelated metal and functional groups. The unique behavior of functionalized corroles towards specific cell lines introduces the possibility of targeted chemotherapy. Many anticancer drugs are evaluated by their ability to inhibit RNA transcription. Here we present a step-by-step protocol for RNA transcription in the presence of known and potential inhibitors. The evaluation of the RNA products of the transcription reaction by gel electrophoresis and UV-Vis spectroscopy provides information on inhibitive properties of potential anticancer drug candidates and, with modifications to the assay, more about their mechanism of action. Little is known about the molecular mechanism of action of corrole cytotoxicity. In this experiment, we consider two corrole compounds: gallium(III) 5,10,15-(tris)pentafluorophenylcorrole (Ga(tpfc)) and freebase analogue 5,10,15-(tris)pentafluorophenylcorrole (tpfc). An RNA transcription assay was used to examine the inhibitive properties of the corroles. Five transcription reactions were prepared: DNA treated with Actinomycin D, triptolide, Ga(tpfc), tpfc at a [complex]:[template DNA base] ratio of 0.01, respectively, and an untreated control. The transcription reactions were analyzed after 4 hr using agarose gel electrophoresis and UV-Vis spectroscopy. There is clear inhibition by Ga(tpfc), Actinomycin D, and triptolide. This RNA transcription assay can be modified to provide more mechanistic detail by varying the concentrations of the anticancer complex, DNA, or polymerase enzyme, or by incubating the DNA or polymerase with the complexes prior to RNA transcription; these modifications would differentiate between an inhibition mechanism involving the DNA or the enzyme

  9. Endotoxin in fine (PM 2.5) and coarse (PM 2.5-10) particle mass of ambient aerosols. A temporo-spatial analysis

    NASA Astrophysics Data System (ADS)

    Heinrich, Joachim; Pitz, Mike; Bischof, Wolfgang; Krug, Norbert; Borm, Paul J. A.

    Objectives: We collected fine (PM 2.5) and coarse (PM 2.5-10) particulate matter fractions in two areas ˜80 km apart and measured soluble endotoxin concentrations in both particle fractions. Here we report on temporo-spatial variation of endotoxin content in the collected particles. Methods: Dichotomous Anderson samplers were used to collect 21 weekly samples of PM 2.5 and PM 2.5-10 in both towns from January to June 2002. Each Teflon filter was water extracted and endotoxin was measured by a chromogenic Limulus Amoebocyte Lysate method. Endotoxin concentrations were expressed per mg of fine or mg of coarse mass and per sampled air volume (m 3). Results: For both cities, the mean endotoxin content in PM 2.5 was 1.2 EU mg -1; however the endotoxin content in the coarse fraction was ˜10 times higher compared to the fine mass fractions. Although endotoxin content is highly variable over time, a good correlation was observed between the two town sites for both fine ( r=0.85) and coarse PM ( r=0.88). The fluctuations of weekly endotoxin means were high in both areas suggesting a strong temporal dependence on particle source and composition. The endotoxin content in particles collected during May and June were two to four times higher than concentrations measured during the winter and early spring weeks. Conclusions: Ambient airborne endotoxin concentrations were detected in coarse and fine particle fraction, but 10-fold higher in the coarse PM. The strong seasonality and the week to week fluctuation of endotoxin content in PM indicate different biologic PM properties which might affect results of time series studies on short-term effects as well as in vitro studies and human exposure studies.

  10. Antimony release from contaminated mine soils and its migration in four typical soils using lysimeter experiments.

    PubMed

    Shangguan, Yu-Xian; Zhao, Long; Qin, Yusheng; Hou, Hong; Zhang, Naiming

    2016-11-01

    Antimony (Sb) can pose great risks to the environment in mining and smelting areas. The migration of Sb in contaminated mine soil was studied using lysimeter experiments. The exchangeable concentration of soil Sb decreased with artificial leaching. The concentrations of Sb retained in the subsoil layers (5-25cm deep) were the highest for Isohumosol and Ferrosol and the lowest for Sandy soil. The Sb concentrations in soil solutions decreased with soil depth, and were adequately simulated using a logarithmic function. The Sb migration pattern in Sandy soil was markedly different from the patterns in the other soils which suggested that Sb may be transported in soil colloids. Environmental factors such as water content, soil temperature, and oxidation-reduction potential of the soil had different effects on Sb migration in Sandy soil and Primosol. The high Fe and Mn contents in Ferrosol and Isohumosol significantly decreased the mobility of Sb in these soils. The Na and Sb concentrations in soils used in the experiments positively correlated with each other (P<0.01). The Sb concentrations in soil solutions, the Sb chemical fraction patterns, and the Sb/Na ratios decreased in the order Sandy soil>Primosol>Isohumosol>Ferrosol, and we concluded that the Sb mobility in the soils also decreased in that order. PMID:27395817

  11. Antimony release from contaminated mine soils and its migration in four typical soils using lysimeter experiments.

    PubMed

    Shangguan, Yu-Xian; Zhao, Long; Qin, Yusheng; Hou, Hong; Zhang, Naiming

    2016-11-01

    Antimony (Sb) can pose great risks to the environment in mining and smelting areas. The migration of Sb in contaminated mine soil was studied using lysimeter experiments. The exchangeable concentration of soil Sb decreased with artificial leaching. The concentrations of Sb retained in the subsoil layers (5-25cm deep) were the highest for Isohumosol and Ferrosol and the lowest for Sandy soil. The Sb concentrations in soil solutions decreased with soil depth, and were adequately simulated using a logarithmic function. The Sb migration pattern in Sandy soil was markedly different from the patterns in the other soils which suggested that Sb may be transported in soil colloids. Environmental factors such as water content, soil temperature, and oxidation-reduction potential of the soil had different effects on Sb migration in Sandy soil and Primosol. The high Fe and Mn contents in Ferrosol and Isohumosol significantly decreased the mobility of Sb in these soils. The Na and Sb concentrations in soils used in the experiments positively correlated with each other (P<0.01). The Sb concentrations in soil solutions, the Sb chemical fraction patterns, and the Sb/Na ratios decreased in the order Sandy soil>Primosol>Isohumosol>Ferrosol, and we concluded that the Sb mobility in the soils also decreased in that order.

  12. Changes in microbial activity of soils during the natural restoration of abandoned lands in central Russia

    NASA Astrophysics Data System (ADS)

    Ovsepyan, Lilit; Mostovaya, Anna; Lopes de Gerenyu, Valentin; Kurganova, Irina

    2015-04-01

    Most changes in land use affect significantly the amount of soil organic carbon (SOC) and alter the nutrition status of soil microbial community. The arable lands withdrawal induced usually the carbon sequestration in soil, the significant shifts in quality of soil organic matter and structure of microbial community. This study was aimed to determine the microbial activity of the abandoned lands in Central Russia due to the process of natural self-restoration. For the study, two representative chronosequences were selected in Central Russia: (1) deciduous forest area, DFA (Moscow region, 54o49N'; 37o34'E; Haplic Luvisols) and (2) forest steppe area, FSA (Belgorod region 50o36'N, 36o01'E Luvic Phaeozems). Each chronosequence included current arable, abandoned lands of different age, and forest plots. The total soil organic carbon (Corg, automatic CHNS analyzer), carbon immobilized in microbial biomass (Cmic, SIR method), and respiratory activity (RA) were determined in the topsoil (0-5, 5-10, 10-20 and 20-30 cm layers) for each plots. Relationships between Corg, Cmic, and RA were determined by liner regression method. Our results showed that the conversion of croplands to the permanent forest induced the progressive accumulation Corg, Cmic and acceleration of RA in the top 10-cm layer for both chronosequences. Carbon stock increased from 24.1 Mg C ha-1 in arable to 45.3 Mg C ha-1 in forest soil (Luvic Phaeozems, Belgorod region). In Haplic Luvisols (Moscow region), SOC build up was 2 time less: from 13.5 Mg C ha-1 in arable to 27.9 Mg C ha-1 in secondary forest. During post-agrogenic evolution, Cmic also increased significantly: from 0.34 to 1.43 g C kg-1 soil in Belgorod region and from 0.34 to 0.64 g C kg-1 soil in Moscow region. RA values varied widely in soils studied: from 0.54-0.63 mg C kg-1h-1 in arable plots to 2.02-3.4 mg C kg-1h-1 in forest ones. The close correlations between Cmic, RA and Corg in the top 0-5cm layer (R2 = 0.81-0.90; P<0.01-0.05) were

  13. CONSTRUCTION, MONITORING, AND PERFORMANCE OF TWO SOIL LINERS

    EPA Science Inventory

    A prototype soil liner and a field-scale soil liner were constructed to test whether compacted soil barrier systems could be built to meet the standard set by the U.S. Environmental Protection Agency (EPA) for saturated hydraulic conductivity (< 1 x 10'7 cm/s). In situ ponded inf...

  14. Changes in quantity and spectroscopic properties of water-extractable organic matter during soil aquifer treatment.

    PubMed

    Xue, S; Zhao, Q L; Wei, L L; Ma, X P; Tie, M

    2013-01-01

    The aim of this study was to identify qualitative and quantitative changes in the character of water-extractable organic matter (WEOM) in soils as a consequence of soil aquifer treatment (SAT). Soil samples were obtained from a soil-column system with a 2-year operation, and divided into seven layers from top to bottom: CS1 (0-12.5 cm), CS2 (12.5-25 cm), CS3 (25-50 cm), CS4 (50-75 cm), CS5 (75-100 cm), CS6 (100-125 cm) and CS7 (125-150 cm). A sample of the original soil used to pack the columns was also analysed to determine the effects of SAT. Following 2 years of SAT operation, both soil organic carbon and water-extractable organic carbon were shown to accumulate in the top soil layer (0-12.5 cm), and to decrease in soil layers deeper than 12.5 cm. The WEOM in the top soil layer was characterized by low aromaticity index (AI), low emission humification index (HIX) and low fluorescence efficiency index (F(eff)). On the other hand, the WEOM in soil layers deeper than 12.5 cm had increased values of HIX and F(eff), as well as decreased AI values relative to the original soil before SAT. In all soil layers, the percentage of hydrophobic and transphilic fractions decreased, while that of the hydrophilic fraction increased, as a result of SAT. The production of the amide-2 functional groups was observed in the top soil layer. SAT operation also led to the enrichment of hydrocarbon and amide-1 functional groups, as well as the depletion of oxygen-containing functional groups in soil layers deeper than 12.5 cm.

  15. Airflow dispersion in unsaturated soil.

    PubMed

    Gidda, T; Cann, D; Stiver, W H; Zytner, R G

    2006-01-01

    Dispersion data is abundant for water flow in the saturated zone but is lacking for airflow in unsaturated soil. However, for remediation processes such as soil vapour extraction, characterization of airflow dispersion is necessary for improved modelling and prediction capabilities. Accordingly, gas-phase tracer experiments were conducted in five soils ranging from uniform sand to clay at air-dried and wetted conditions. The disturbed soils were placed in one-dimensional stainless steel columns, with sulfur hexafluoride used as the inert tracer. The tested interstitial velocities were typical of those present in the vicinity of a soil vapour extraction well, while wetting varied according to the water-holding capacity of the soils. Results gave dispersivities that varied between 0.42 and 2.6 cm, which are typical of values in the literature. In air-dried soils, dispersion was found to increase with the pore size variability of the soil. For wetted soils, particle shape was an important factor at low water contents, while at high water contents, the proportion of macroporous space filled with water was important. The relative importance of diffusion decreased with increasing interstitial velocity and water content and was, in general, found to be minor compared to mechanical mixing across all conditions studied. PMID:16246460

  16. Impact of drainage on wettability of fen peat-moorsh soils

    NASA Astrophysics Data System (ADS)

    Szajdak, L.; Szatyłowicz, J.; Brandyk, T.

    2009-04-01

    High water retention in peat is attributed to structural voids (macro-pores) due to the partial degradation of the structure of peat-forming plants, and molecular absorption sites (micro-pores) associated with the formation of humic substances. Water retention by the heterogeneously-structured system in peat organic matter depends on the chemical structure of solid surfaces. These naturally wet solids, if dried sufficiently, lose the ability to rewet quickly when immersed in water. The ability of peat surfaces to attract and hold water is attributed to hydrophilic functional groups which characterize the organic substances of peat. The investigations of chemical and physical properties were performed for three different peat-moorsh soils located in the Biebrza River Valley in Poland. All examined soils were used as meadow. Soil samples were taken from two depths: 5-10 cm (moorsh) and 50-80 cm (peat). Total organic carbon (TOC), dissolved organic carbon (DOC) and humic acids (HA) extracted from these samples were analysed. Also basic physical properties such as ash content and bulk density were measured. Wetting behavior of soils was quantified using water drop penetration time test (WDPT) and measured values of the soil-water contact angle using sessile drop method. The measurements were conducted on air-dry soil samples which volumetric moisture content was not exceeding 7%. The significant differences in the concentrations of TOC, DOC and properties of HA between two investigated depth of among peat and moorsh samples were observed. The measured concentrations of total organic carbon in the considered soils ranged from 37.2 to 45.6%. Generally, the decrease of total organic carbon concentration with depth of profiles was observed. The contents of dissolved organic carbon in the soils ranged from 5.3 to 19.4%. The quantities of dissolved organic carbon decreased simultaneously with E4/E6 values and with the depth of the soil profiles. For the investigated peat

  17. Sensitivity of soil organic matter in anthropogenically disturbed organic soils

    NASA Astrophysics Data System (ADS)

    Säurich, Annelie; Tiemeyer, Bärbel; Bechtold, Michel; Don, Axel; Freibauer, Annette

    2016-04-01

    Drained peatlands are hotspots of carbon dioxide (CO2) emissions from agriculture. However, the variability of CO2 emissions increases with disturbance, and little is known on the soil properties causing differences between seemingly similar sites. Furthermore the driving factors for carbon cycling are well studied for both genuine peat and mineral soil, but there is a lack of information concerning soils at the boundary between organic and mineral soils. Examples for such soils are both soils naturally relatively high in soil organic matter (SOM) such as Humic Gleysols and former peat soils with a relative low SOM content due to intensive mineralization or mixing with underlying or applied mineral soil. The study aims to identify drivers for the sensitivity of soil organic matter and therefore for respiration rates of anthropogenically disturbed organic soils, especially those near the boundary to mineral soils. Furthermore, we would like to answer the question whether there are any critical thresholds of soil organic carbon (SOC) concentrations beyond which the carbon-specific respiration rates change. The German agricultural soil inventory samples all agricultural soils in Germany in an 8x8 km² grid following standardized protocols. From this data and sample base, we selected 120 different soil samples from more than 80 sites. As reference sites, three anthropogenically undisturbed peatlands were sampled as well. We chose samples from the soil inventory a) 72 g kg-1 SOC and b) representing the whole range of basic soil properties: SOC (72 to 568 g kg-1), total nitrogen (2 to 29 g kg-1), C-N-ratio (10 to 80) bulk density (0.06 to 1.41 g/cm³), pH (2.5 to 7.4), sand (0 to 95 %) and clay (2 to 70 %) content (only determined for samples with less than 190 g kg-1 SOC) as well as the botanical origin of the peat (if determinable). Additionally, iron oxides were determined for all samples. All samples were sieved (2 mm) and incubated at standardized water content and

  18. Soil Ecology

    NASA Astrophysics Data System (ADS)

    Killham, Ken

    1994-04-01

    Soil Ecology is designed to meet the increasing challenge faced by today's environmental scientists, ecologists, agriculturalists, and biotechnologists for an integrated approach to soil ecology. It emphasizes the interrelations among plants, animals, and microbes, by first establishing the fundamental physical and chemical properties of the soil habitat and then functionally characterizing the major components of the soil biota and some of their most important interactions. The fundamental principles underpinning soil ecology are established and this then enables an integrated approach to explore and understand the processes of soil nutrient (carbon, nitrogen, and phosphorus) cycling and the ecology of extreme soil conditions such as soil-water stress. Two of the most topical aspects of applied soil ecology are then selected. First, the ecology of soil pollution is examined, focusing on acid deposition and radionuclide pollution. Second, manipulation of soil ecology through biotechnology is discussed, illustrating the use of pesticides and microbial inocula in soils and pointing toward the future by considering the impact of genetically modified inocula on soil ecology.

  19. Clumped isotopes in soil carbonate

    NASA Astrophysics Data System (ADS)

    Quade, J.; Eiler, J. M.; Daeron, M.

    2011-12-01

    We are monitoring soil temperature and measuring clumped isotopes from modern soil carbonate in North and South America, Hawaii, and Tibet. Clumped isotopes from 50-200 cm soil depth show a strong and systematic bias toward formation in the warmest summer months. For example, soil carbonate as these depths exceed local mean annual temperature by 10-15°C in soils from India and Tibet. Clumped isotope temperatures from modern carbonate increase very regularly (r2 = 0.90) with elevation gain from lowland India to Tibet. Here carbonate forms largely in May-June, just prior to the arrival of the soil-cooling monsoon rains. In this regard, clumped isotopes hold great promise as a paleoaltimeter on the plateau. The question is whether these patterns from a monsoonal climate can be generalized (and they probably can't be) to other climate regimes when soil carbonate forms at a different time of year than the pre-monsoon. For example, in winter-dominated rainfall regimes soil carbonate may form as soils dewater in the spring and soil temperature is closer to mean annual temperature. These are open questions. Diurnal temperature information is also archived in the upper 30 cm of soils. Modern carbonate in Tibet appears to form in very late morning through afternoon, when the surface soil is warmest. Shade and aspect also strongly influence measured soil and clumped isotope temperatures. Both variables will have to be controlled for to correctly interpret clumped isotopes from the paleosol record. Clumped isotope values correlate with δ13C values in soil carbonate from shallowly buried (<1 km) paleosols from Nepal and Pakistan. This makes sense since δ13C values in the sub-tropics are determined the fraction of tree (C3) to grass (C4) cover, and soils under tree-covered areas are cooler. Finally, clumped isotopes from carbonates are reset to higher temperatures at burial depths roughly >2-3 km or >50-75°C. This was reproduced from paleosol and lake carbonates from three

  20. Zinc movement in sewage-sludge-treated soils as influenced by soil properties, irrigation water quality, and soil moisture level

    USGS Publications Warehouse

    Welch, J.E.; Lund, L.J.

    1989-01-01

    A soil column study was conducted to assess the movement of Zn in sewage-sludge-amended soils. Varables investigated were soil properties, irrigation water quality, and soil moisture level. Bulk samples of the surface layer of six soil series were packed into columns, 10.2 cm in diameter and 110 cm in length. An anaerobically digested municipal sewage sludge was incorporated into the top 20 cm of each column at a rate of 300 mg ha-1. The columns were maintained at moisture levels of saturation and unsaturation and were leached with two waters of different quality. At the termination of leaching, the columns were cut open and the soil was sectioned and analyzed. Zinc movement was evaluated by mass balance accounting and correlation and regression analysis. Zinc movement in the unsaturated columns ranged from 3 to 30 cm, with a mean of 10 cm. The difference in irrigation water quality did not have an effect on Zn movement. Most of the Zn applied to the unsaturated columns remained in the sludge-amended soil layer (96.1 to 99.6%, with a mean of 98.1%). The major portion of Zn leached from the sludge-amended soil layer accumulated in the 0- to 3-cm depth (35.7 to 100%, with a mean of 73.6%). The mean final soil pH values decreased in the order: saturated columns = sludge-amended soil layer > untreated soils > unsaturated columns. Total Zn leached from the sludge-amended soil layer was correlated negatively at P = 0.001 with final pH (r = -0.85). Depth of Zn movement was correlated negatively at P = 0.001 with final pH (r = -0.91). Multiple linear regression analysis showed that the final pH accounted for 72% of the variation in the total amounts of Zn leached from the sludge-amended soil layer of the unsaturated columns and accounted for 82% of the variation in the depth of Zn movement among the unsaturated columns. A significant correlation was not found between Zn and organic carbon in soil solutions, but a negative correlation significant at P = 0.001 was found

  1. Cloning of chrysanthemum high-affinity nitrate transporter family (CmNRT2) and characterization of CmNRT2.1.

    PubMed

    Gu, Chunsun; Song, Aiping; Zhang, Xiaoxue; Wang, Haibin; Li, Ting; Chen, Yu; Jiang, Jiafu; Chen, Fadi; Chen, Sumei

    2016-01-01

    The family of NITRATE TRANSPORTER 2 (NRT2) proteins belongs to the high affinity transport system (HATS) proteins which acts at low nitrate concentrations. The relevant gene content of the chrysanthemum genome was explored here by isolating the full length sequences of six distinct CmNRT2 genes. One of these (CmNRT2.1) was investigated at the functional level. Its transcription level was inducible by low concentrations of both nitrate and ammonium. A yeast two hybrid assay showed that CmNRT2.1 interacts with CmNAR2, while a BiFC assay demonstrated that the interaction occurs at the plasma membrane. Arabidopsis thaliana plants heterologously expressing CmNRT2.1 displayed an enhanced rate of labeled nitrogen uptake, suggesting that CmNRT2.1 represents a high affinity root nitrate transporter. PMID:27004464

  2. The effect of soil on cork quality

    NASA Astrophysics Data System (ADS)

    Pestana, Miguel; Gomes, Alberto

    2014-10-01

    The present work aimed to contribute for a better knowledge regarding soil features as cork quality indicators for stoppers. Cork sampling was made in eight Cork oak stands (montados de sobreiro) located in different Plio-Plistocene sedimentary formations of Península de Setúbal and Carbonic shistes from paleozoic periods in Saw Grândola, both in southern Tagus River region The samples used to classify the cork as stopper for wine bottles were obtained in eight cork oak stands located in “Península de Setúbal”, south of the River Tagus, covering soils of different types of sandstones of the Plio-plistocene In each stand, we randomly chose five circular plots with 30 m radius. Five trees with same stripping conditions determined by the dendrometric features: HD (height stipping, PBH (perimeter at breaster height), and percentage canopy cover, trees vegetative condition (defoliation degree) stand features (density), and site conditions (soil type and orientation). In the center of each plot a pit was open to characterize the soil profile and to classify the soil of each plot sampling. Cork quality for stoppers was evaluated according to porosity, pores/per cm 2 and thickness. The soil was characterized according to morphological soil profile features (lithology, soil profound and soil horizons) and chemical soil surface horizon features (organic matter, pH, macro and micronutrients availability). Based on the variables studied and using the numerical taxonomy, we settled relationships between the cork quality and some soil features. The results indicate: (1) high correlation between the cork caliber and boron, caption exchange capacity, total nitrogen, exchange acidity and exchangeable magnesium, potassium, calcium and sodium in soils of theirs cork oaks; (2) the cork porosity is correlated with the number of pores/cm2 and magnesium; (3) the other soil features have a lower correlation with the caliber, porosity and the number of pores per cm2.

  3. [Microelement contents of litter, soil fauna and soil in Pinus koraiensis and broad-leaved mixed forest].

    PubMed

    Yin, Xiu-qin; Li, Jin-xia; Dong, Wei-hua

    2007-02-01

    The analysis on the Mn, Zn and Cu contents of litter, soil fauna and soil in Pinus korazenszis and broad-leaved mixed forest in Liangshui Natural Reserve of Xiaoxing' an Mountains showed that the test microelement contents in the litter, soil fauna and soil all followed the sequence of Mn > Zn > Cu, but varied with these environmental components, being in the sequence of soil > litter > soil fauna for Mn, soil fauna > litter and soil for Zn, and soil fauna > soil > litter for Cu. The change range of test microelement contents in litter was larger in broad-leaved forest than in coniferous forest. Different soil fauna differed in their microelement-enrichment capability, e. g. , earthworm, centipede, diplopod had the highest content of Mn, Zn and Cu, respectively. The contents of test microelements in soil fauna had significant correlations with their environmental background values, litter decomposition rate, food habit of soil fauna, and its absorbing selectivity and enrichment to microelements. The microelements contained in 5-20 cm soil layer were more than those in 0-5 cm soil layer, and their dynamics differed in various soil layers.

  4. Soil penetrometer

    NASA Technical Reports Server (NTRS)

    Howard, E. A.; Hotz, G. M.; Bryson, R. P. (Inventor)

    1968-01-01

    An auger-type soil penetrometer for burrowing into soil formations is described. The auger, while initially moving along a predetermined path, may deviate from the path when encountering an obstruction in the soil. Alterations and modifications may be made in the structure so that it may be used for other purposes.

  5. Diffusion of iodine and Technetium-99 through waste encasement concrete and unsaturated soil fill material

    SciTech Connect

    Mattigod, Shas V.; Whyatt, Greg A.; Serne, R JEFFREY.; Wood, Marcus I.; John M. Hanchar, Simcha Stores-Gascoyne, Lauren Browning

    2004-10-30

    An assessment of long-term performance of low level waste-enclosing cement grouts requires diffusivity data for radionuclide species such as, 129I and 99Tc. The diffusivity of radionuclides in soil and concrete media was collected by conducting soil-soil and concrete-soil half-cell experiments. The soil diffusivity coefficients for iodide were 7.03 x 10-8 cm2/s and 2.42 x 10-7 cm2/s for soils at 4% and 7% moisture contents, respectively. Iodide diffusivity in soil is a function of moisture content and is about an order of magnitude slower at lower moisture content. The soil diffusivity coefficients for 99Tc were 5.89 {+-} 0.80 x 10-8 cm2/s (4% moisture content) and 2.04 {+-} 0.57 x 10-7 cm2/s (7% moisture content), respectively. The soil diffusivity of iodide and 99Tc were similar in magnitude at both water contents, indicating that these ions have similar diffusion mechanisms in unsaturated coarse-textured Hanford soil. The diffusivity of iodide in concrete ranged from 2.07 x 10-14 cm2/s (4% soil moisture content) to 1.31 x 10-12 cm2/s (7% soil moisture content), indicating that under unsaturated soil moisture conditions, iodide diffusivity is highly sensitive to changing soil moisture conditions. Depending on the soil moisture content, the diffusivity of 99Tc in concrete ranged from 4.54 x 10-13 cm2/s to 8.02 x 10-12 cm2/s. At 4% soil moisture content, iodide diffused about 20 times more slowly than 99Tc, and at 7% soil moisture content, iodide in concrete diffused about 6 times slower than 99Tc.

  6. Effect of integrating straw into agricultural soils on soil infiltration and evaporation.

    PubMed

    Cao, Jiansheng; Liu, Changming; Zhang, Wanjun; Guo, Yunlong

    2012-01-01

    Soil water movement is a critical consideration for crop yield in straw-integrated fields. This study used an indoor soil column experiment to determine soil infiltration and evaporation characteristics in three forms of direct straw-integrated soils (straw mulching, straw mixing and straw inter-layering). Straw mulching is covering the land surface with straw. Straw mixing is mixing straw with the top 10 cm surface soil. Then straw inter-layering is placing straw at the 20 cm soil depth. There are generally good correlations among the mulch integration methods at p < 0.05, and with average errors/biases <10%. Straw mixing exhibited the best effect in terms of soil infiltration, followed by straw mulching. Due to over-burden weight-compaction effect, straw inter-layering somehow retarded soil infiltration. In terms of soil water evaporation, straw mulching exhibited the best effect. This was followed by straw mixing and then straw inter-layering. Straw inter-layering could have a long-lasting positive effect on soil evaporation as it limited the evaporative consumption of deep soil water. The responses of the direct straw integration modes to soil infiltration and evaporation could lay the basis for developing efficient water-conservation strategies. This is especially useful for water-scarce agricultural regions such as the arid/semi-arid regions of China.

  7. Effect of integrating straw into agricultural soils on soil infiltration and evaporation.

    PubMed

    Cao, Jiansheng; Liu, Changming; Zhang, Wanjun; Guo, Yunlong

    2012-01-01

    Soil water movement is a critical consideration for crop yield in straw-integrated fields. This study used an indoor soil column experiment to determine soil infiltration and evaporation characteristics in three forms of direct straw-integrated soils (straw mulching, straw mixing and straw inter-layering). Straw mulching is covering the land surface with straw. Straw mixing is mixing straw with the top 10 cm surface soil. Then straw inter-layering is placing straw at the 20 cm soil depth. There are generally good correlations among the mulch integration methods at p < 0.05, and with average errors/biases <10%. Straw mixing exhibited the best effect in terms of soil infiltration, followed by straw mulching. Due to over-burden weight-compaction effect, straw inter-layering somehow retarded soil infiltration. In terms of soil water evaporation, straw mulching exhibited the best effect. This was followed by straw mixing and then straw inter-layering. Straw inter-layering could have a long-lasting positive effect on soil evaporation as it limited the evaporative consumption of deep soil water. The responses of the direct straw integration modes to soil infiltration and evaporation could lay the basis for developing efficient water-conservation strategies. This is especially useful for water-scarce agricultural regions such as the arid/semi-arid regions of China. PMID:22643418

  8. Optimizing rainwater partitioning and millet production on degraded land in Niger using Water and Soil Conservation practices

    NASA Astrophysics Data System (ADS)

    Wildemeersch, Jasmien C. J.; Garba, Maman; Al-Barri, Bashar; Sabiou, Mahamane; Cornelis, Wim M.

    2015-04-01

    As a result of growing population pressure and severe soil erosion, farmers in the Sahel increasingly rely on degraded lands for millet production. The adverse Sahelian rainfall distribution and imbalanced rainfall partitioning over the rootzone of these degraded lands therefore calls for sustainable land management strategies that are water resource efficient. This study evaluates the soil-water balance of promising Nigerien Water and Soil Conservation (WSC) techniques (i.e., zaï pits, demi-lune microcatchments and scarification with standing crop residue) and their impact on millet yield by means of an in-situ field experiment (2011-2013) on degraded laterite soil classified as Plinthosol with a 1% slope. All WSC practices received the same amount of fertilizer and were compared to two control practices, one with and one without fertilizer. Soil-water content was recorded with a neutron probe till 105 cm depth and runoff by means of a cemented gutter directing runoff water with a multi-pipe divisor into a collector drum. WSC techniques proved to significantly reduce runoff (blue water) with overall runoff coefficients beings reduced from 25% (control practice) to 5-10%. Consequently, significantly more water was stored inside the catchments of the zaï pits and demi-lunes (green water). With the scarification treatment, no considerable differences in soil-water storage were found with the control. On the other hand, WSC practices had little impact on soil evaporation, which was only 12% of rainfall by the self-mulching soil. Crop transpiration increased with WSC and highest millet yields were found with zaï pits (4 to 5 times higher than under the fertilized control). Although rainwater was better partitioned in case of demi-lune microcatchments resulting in highest amounts of water stored in the soil, yield was only 40-60% of that with zaï pits. This was due to a higher plant density within each demi-lune microcatchment in an attempt to attain similar plant

  9. Effects of dietary glycerin inclusion at 0, 5, 10, and 15 percent of dry matter on energy metabolism and nutrient balance in finishing beef steers.

    PubMed

    Hales, K E; Foote, A P; Brown-Brandl, T M; Freetly, H C

    2015-01-01

    Expansion of the biodiesel industry has increased the glycerin (GLY) supply. Glycerin is an energy-dense feed that can be used in ruminant species; however, the energy value of GLY is not known. Therefore, the effects of GLY inclusion at 0, 5, 10, and 15% on energy balance in finishing cattle diets were evaluated in 8 steers (BW = 503 kg) using a replicated Latin square design. Data were analyzed with the fixed effects of dietary treatment and period, and the random effects of square and steer within square were included in the model. Contrast statements were used to separate linear and quadratic effects of GLY inclusion. Glycerin replaced dry-rolled corn (DRC) at 0, 5, 10, and 15% of dietary DM. Dry matter intake decreased linearly (P = 0.02) as GLY increased in the diet. As a proportion of GE intake, fecal energy loss tended to decrease linearly (P < 0.07), and DE also tended to increase linearly (P = 0.07) as dietary level of GLY increased. Urinary energy loss was not different (P > 0.31) as a proportion of GE as GLY increased in the diet. Methane energy loss as a proportion of GE intake tended to respond quadratically (P = 0.10), decreasing from 0 to 10% GLY inclusion and increasing thereafter. As a proportion of GE intake, ME tended to respond quadratically (P = 0.10), increasing from 0 to 10% GLY and then decreasing. As a proportion of GE intake, heat production increased linearly (P = 0.02) as GLY increased in the diet. Additionally, as a proportion of GE intake, retained energy (RE) tended to respond quadratically (P = 0.07), increasing from 0 to 10% GLY inclusion and decreasing thereafter. As a proportion of N intake, urinary and fecal N excretion increased linearly (P < 0.04) as GLY increased in the diet. Furthermore, grams of N retained and N retained as a percent of N intake both decreased linearly (P < 0.02) as GLY increased in the diet. Total DM digestibility tended (P < 0.10) to respond quadratically, increasing at a decreasing rate from 0 to 5% GLY

  10. Impact of alpine meadow degradation on soil hydraulic properties over the Qinghai-Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Zeng, Chen; Zhang, Fan

    2015-04-01

    Alpine meadow is one of widespread vegetation types of the Qinghai-Tibetan Plateau. It is undergoing degradation under the background of global climate change, human activities and overgrazing. Soil moisture is important to alpine meadow ecology for its water and energy transfer processes, therefore soil hydraulic properties become key parameters for local eco-hydrological processes studies. However, little research focus on the changes and it's mechanisms of soil hydraulic properties during the degradation processes. In this study, soil basic and hydraulic properties at 0-10 cm and 40-50 cm soil layer depths under different degraded alpine meadow were analyzed. Pearson correlations were adopted to study the relationships among the investigated factors and principal component analysis was performed to identify the dominant factor. Results show that with increasing degree of degradation, soil sand content increased while soil saturated hydraulic conductivity (Ks) as well as soil clay content, soil porosity decreased in the 0-10 cm soil layers, and organic matter and root gravimetric density decreased in both the 0-10 cm and 40-50 cm soil layers. For soil unsaturated hydraulic conductivity, it reduced more slowly with decreasing pressure head under degraded conditions than non-degraded conditions. However, soil moisture showed no significant changes with increasing degradation. Soil Ks was significantly correlated (P = 0.01) with bulk density, soil porosity, soil organic matter and root gravimetric density. Among these, soil porosity is the dominant factor explaining about 90% of the variability in total infiltration flow. Under non-degraded conditions, the infiltration flow principally depended on the presence of macropores. With increasing degree of degradation, soil macropores quickly changed to mesopores or micropores. The proportion of total infiltration flow through macropores and mesopores significantly decreased with the most substantial decrease observed for

  11. Pyromineralization of soil phosphorus in savanna ecosystems

    NASA Astrophysics Data System (ADS)

    Hartshorn, A.; Coetsee, C.; Chadwick, O.

    2007-12-01

    The weathering of rock supplies phosphorus (P) to ecosystems. Phosphorus limitation of ecosystems can be severe in thicker or older soils, where soil production rates from rock and therefore release of P is slower than in thinner or younger soils. Limitation may be especially pronounced in drier ecosystems that are experiencing increasing N deposition. Our savanna field sites in Kruger National Park, South Africa meet all three of these criteria: soil residence times average 250 ky, the climate is semiarid, and N inputs average 20 kg ha-1 y-1. Not all soil P is plant-available, and because our field sites experience occasional fires, our objectives were to quantify the importance of pyromineralization of soil P, the transfer by fire of soil P from recalcitrant to labile (HCO3- extractable) pools. We quantified these soil P pools using a modified Hedley scheme (an array of chemical extractants). Three sets of soils were fractionated: 1. soils from 10 profiles along an intensively studied hillslope, bracketing a pronounced structural and functional ecotone; 2. surface soils from these 10 profiles after a simulated burn; and 3. surface soils from the Shabeni Experimental Plots, where 4 fire treatments have been maintained for decades: no fire, annual fire in the dry season, triennial fire in the dry season, and triennial fire in the wet season. Total P for hillslope soils ranged from 45 to 135 g m-2 (to 50 cm depth) and from 8 to 15 g m-2 (to 5 cm depth). Total soil P was lowest in midslope soils, where upslope sandy soils dominated by broad-leafed vegetation shift abruptly to downslope clayey soils with fine-leafed vegetation. Simulated fire for the hillslope soils reduced total P slightly, but boosted labile P by 1.7 g m-2 (to 5 cm), representing 17% of total P in the surface 5 cm. This pyromineralization effect was not uniform across the hillslope: downslope soils gained about 50% more labile P than midslope soils with simulated burning. With a fire return interval

  12. Isotopic Pu, Am and Cm signatures in environmental samples contaminated by the Fukushima Dai-ichi Nuclear Power Plant accident.

    PubMed

    Yamamoto, M; Sakaguchi, A; Ochiai, S; Takada, T; Hamataka, K; Murakami, T; Nagao, S

    2014-06-01

    Dust samples from the sides of roads (black substances) have been collected together with litter and soil samples at more than 100 sites contaminated heavily in the 20-km exclusion zones around Fukushima Dai-ichi Nuclear Power Plant (FDNPP) (Minamisoma City, and Namie, Futaba and Okuma Towns), in Iitate Village located from 25 to 45 km northwest of the plant and in southern areas from the plant. Isotopes of Pu, Am and Cm have been measured in the samples to evaluate their total releases into the environment from the FDNPP and to get the isotopic compositions among these nuclides. For black substances and litter samples, in addition to Pu isotopes, (241)Am, (242)Cm and (243,244)Cm were determined for most of samples examined, while for soil samples, only Pu isotopes were determined. The results provided a coherent data set on (239,240)Pu inventories and isotopic composition among these transuranic nuclides. When these activity ratios were compared with those for fuel core inventories in the FDNPP accident estimated by a group at JAEA, except (239,240)Pu/(137)Cs activity ratios, fairly good agreements were found, indicating that transuranic nuclides, probably in the forms of fine particles, were released into the environment without their large fractionations. The obtained data may lead to more accurate information about the on-site situation (e.g., burn-up, conditions of fuel during the release phase, etc.), which would be difficult to get otherwise, and more detailed information on the dispersion and deposition processes of transuranic nuclides and the behavior of these nuclides in the environment. PMID:24531259

  13. Radar reflectivity of bare and vegetation-covered soil

    NASA Technical Reports Server (NTRS)

    Ulaby, F. T.; Dobson, M. C.; Bradley, G. A.

    1981-01-01

    Radar sensitivity to soil moisture content has been investigated experimentally for bare and vegetation-covered soil using detailed spectral measurements obtained by a truck-mounted radar spectrometer in the 1-8 GHz band and by airborne scatterometer observations at 1.6, 4.75, and 13.3 GHz. It is shown that radar can provide quantitative information on the soil moisture content of both bare and vegetation-covered soil. The observed soil moisture is in the form of the soil matric potential or a related quantity such as the percent of field capacity. The depth of the monitored layer varies from 1 cm for very wet soil to about 15 cm for very dry soil.

  14. [Characteristics of soil pH and exchangeable acidity in red soil profile under different vegetation types].

    PubMed

    Ji, Gang; Xu, Ming-gang; Wen, Shi-lin; Wang, Bo-ren; Zhang, Lu; Liu, Li-sheng

    2015-09-01

    The characteristics of soil pH and exchangeable acidity in soil profile under different vegetation types were studied in hilly red soil regions of southern Hunan Province, China. The soil samples from red soil profiles within 0-100 cm depth at fertilized plots and unfertilized plots were collected and analyzed to understand the profile distribution of soil pH and exchangeable acidity. The results showed that, pH in 0-60 cm soil from the fertilized plots decreased as the following sequence: citrus orchard > Arachis hypogaea field > tea garden. As for exchangeable acidity content, the sequence was A. hypogaea field ≤ citrus orchard < tea garden. After tea tree and A. hypogaea were planted for long time, acidification occurred in surface soil (0-40 cm), compared with the deep soil (60-100 cm), and soil pH decreased by 0.55 and 0.17 respectively, but such changes did not occur in citrus orchard. Soil pH in 0-40 cm soil from the natural recovery vegetation unfertilized plots decreased as the following sequence: Imperata cylindrica land > Castanea mollissima garden > Pinus elliottii forest ≥ Loropetalum chinensis forest. As for exchangeable acidity content, the sequence was L cylindrica land < C. mollissima garden < L. chinensis forest ≤ P. elliottii forest. Soil pH in surface soil (0-20 cm) from natural forest plots, secondary forest and Camellia oleifera forest were significantly lower than that from P. massoniana forest, decreased by 0.34 and 0.20 respectively. For exchangeable acidity content in 0-20 cm soil from natural forest plot, P. massoniana forest and secondary forest were significantly lower than C. oleifera forest. Compared with bare land, surface soil acidification in unfertilized plots except I. cylindrica land had been accelerated, and the natural secondary forest was the most serious among them, with surface soil pH decreasing by 0.52. However, the pH increased in deep soils from unfertilized plots except natural secondary forest, and I. cylindrica

  15. [Characteristics of soil pH and exchangeable acidity in red soil profile under different vegetation types].

    PubMed

    Ji, Gang; Xu, Ming-gang; Wen, Shi-lin; Wang, Bo-ren; Zhang, Lu; Liu, Li-sheng

    2015-09-01

    The characteristics of soil pH and exchangeable acidity in soil profile under different vegetation types were studied in hilly red soil regions of southern Hunan Province, China. The soil samples from red soil profiles within 0-100 cm depth at fertilized plots and unfertilized plots were collected and analyzed to understand the profile distribution of soil pH and exchangeable acidity. The results showed that, pH in 0-60 c