bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural characterization of azoic dye hosted layered double hydroxides
Authors: Mandal Sujata , Lerner Dan A. , Marcotte Nathalie , Tichit Didier
Published: May 2009

The removal of methyl orange (MO) from an aqueous solution was performed using layered double hydroxides (LDHs) in a move to develop cleaning processes of effluents contaminated with dye molecules. The intercalation of the guest anionic MO species into host MII/AlIII LDHs differing by the nature of the divalent cations (MII = Mg, Ni or Zn) was achieved by anionic exchange of the initially NO3
– present in the interlayer space and led to MO/LDH intercalation compounds. The exchange process was followed by XRD and UV-visible absorption spectroscopy at different stages. Almost all MO in solution is uptaken by the Mg-containing LDH in the concentration range corresponding to its anionic exchange capacity (AEC). A lower exchange is reached with the Ni- and Zn-containing LDHs, for which the diffusion of MO is limited due to a larger crystallite size. MO–Zn/Al LDH intercalation compounds exhibit the highest crystallinity and display a remarkable stacking of the layers at maximal MO exchange. This behaviour can be assigned to the higher intrinsic charge density of the host layers in agreement with its lower MII/AlIII molar ratio (ZnII/AlIII ≈ 1.5 whereas MgII/AlIII and NiII/AlIII = 2). The maximum amount of MO retained by the different LDHs is higher for Mg-containing LDH, than for Ni- and Zn-containing LDH, reaching respectively 1.15, 0.84 and 0.77 g/g.
Transient hyper-17-hydroxyprogesteronemia: a clinical subgroup of patients diagnosed at neonatal screening for congenital adrenal hyperplasia
Authors: Cavarzere Paolo , Samara-Boustani Dinane , Flechtner Isabelle , Dechaux Michèle , Elie Caroline , Tardy Véronique , Morel Yves , Polak Michel
Published: May 2009

Objective

Neonatal screening for congenital adrenal hyperplasia (CAH) is characterized by a high false-positive rate, mainly among preterm and low birth weight infants. The aims of this study were to describe a subgroup of infants with transient serum hyper-17-hydroxyprogesteronemia (hyper-17-OHPemia) and to compare them with false positive and affected by 21-hydroxylase deficiency newborns.

Methods

We retrospectively analyzed the clinical data of all newborns positive at CAH neonatal screening, who were referred to our hospital to confirm the diagnosis from 2002 to 2006. They were submitted to clinical investigations and blood tests to evaluate 17-hydroxyprogesterone (17-OHP), renin, and electrolyte levels. CAH-unaffected newborns with increased serum 17-OHP were submitted to strict follow-up monitoring, which included an ACTH-stimulating test and genetic analysis of the 21-hydroxylase gene, until serum 17-OHP decreased.

Results

Thirty-seven newborns with gestational ages ranging from 33 to 40 weeks were studied. Eight infants (three male and five female) were affected by CAH (serum 17-OHP: 277.5 (210–921) nmol/l), 14 (ten male and four female) were false positives (17-OHP: 3.75 (0.3–8.4) nmol/l), and 15 (ten male and five female) showed a serum hyper-17-OHPemia (17-OHP: 15.9 (9.9–33) nmol/l). No mutations of the 21-hydroxylase gene were found in infants with hyper-17-OHPemia and their serum 17-OHP levels were normalized by the third month of life.

Conclusion

We identified a population of infants with transient serum hyper-17-OHPemia, and no clinical signs of disease or 21-hydroxylase gene mutations. No further investigations are necessary after birth in these newborns if 17-OHP levels decrease, other confirmatory tests such as ACTH-stimulation test or genotyping analysis are necessary only if symptoms appear.
Diagnostic Value of Immature Neutrophils (Bands) in the Cerebrospinal Fluid of Children With Cerebrospinal Fluid Pleocytosis
Authors: Kanegaye John T. , Nigrovic Lise E. , Malley Richard , Cannavino Christopher R. , Schwab Sandra H. , Bennett Jonathan E. , Mohseni Michael M. , Wang Vincent J. , Katsogridakis Yiannis L. , Herman Martin I. , Kuppermann Nathan ,   for the American Academy of Pediatrics, Pediatric Emergency Medicine Collaborative Research Committee
Published: May 2009

OBJECTIVE. We evaluated the diagnostic utility of the presence and number of cerebrospinal fluid (CSF) bands in distinguishing bacterial from aseptic meningitis among children with CSF pleocytosis.

METHODS. We identified retrospectively a cohort of children 29 days to 19 years of age with CSF pleocytosis (≥10 × 106 leukocytes per L) who were treated in the emergency departments of 8 pediatric centers between January 2001 and June 2004 and whose CSF was evaluated for the presence of bands. We performed bivariate and multivariate analyses to determine the ability of CSF bands to distinguish bacterial from aseptic meningitis.

RESULTS. Among 1116 children whose CSF was evaluated for the presence of bands, 48 children (4% of study patients) had bacterial meningitis. Bacterial meningitis, compared with aseptic meningitis, was associated with a greater CSF band proportion (0.03 vs 0.01; difference: 0.02; 95% confidence interval: 0.00–0.04) and CSF absolute band count (392 × 106 cells per L vs 3 × 106 cells per L; difference: 389 × 106 cells per L; 95% confidence interval: −77 × 106 cells per L to 855 × 106 cells per L). In addition, 29% of patients with bacterial meningitis, compared with 18% of patients with aseptic meningitis, had any bands detected in the CSF. After adjustment for other factors associated with bacterial meningitis, however, CSF band presence, CSF absolute band count, and CSF band proportion were not independently associated with bacterial meningitis.

CONCLUSION. In this multicenter study, neither the presence nor quantity of CSF bands independently predicted bacterial meningitis among children with CSF pleocytosis.
Integration and social support of children of Chinese immigrant families
Authors: Nguyen Luu Lan Anh , Fülöp Márta , Goodwin Robin , Göbel Kerstin , Martín Rojo Luisa , Grad Hector , Berkics Mihály
Published: May 2009

Kínai anyák egy csoportjának beszámolóján keresztül vizsgáltuk kutatásunkban négy európai országban – Magyarországon, Németországban, Spanyolországban és Nagy-Britanniában – élő kínaiak integrációját, szociális támogatottságát, különös tekintettel a magyarországi csoportra. Kérdőíves, 218 kínai anya részvételével végzett vizsgálatunkban a többi csoporthoz képest a magyarországi csoport tagjai kisebb helyi nyelvi kompetenciáról, a helybeliekkel való kapcsolatkeresési hajlandóság alacsonyabb mértékéről, ugyanakkor a transznacionalitás, a Kínával való kapcsolattartás nagyobb intenzitásáról adtak számot. Az itteni kínaiakkal való kapcsolattartási hajlandóságuk viszont nem nagyobb a többi csoportban kapott értékekhez képest, sőt, még alacsonyabb is a nagy-britanniai csoporthoz viszonyítva. A gyerekeik barátai között viszont nagyobb arányban vannak kínai gyerekek, mint más csoportokban. A család mellett az iskola bizonyul a legfontosabb támogatási forrásnak mind a négy országban, mind az érzelmi, mind a praktikus, mind pedig az információs támogatottság terén. Az eredmények valamennyi csoportban több vonatkozásban is az iskola, a tanulás komoly szerepét támasztják alá. Vizsgálati személyeink a kínaiak általános társadalmi integrációjánál sikeresebbnek ítélik az iskolai integrációt, ugyanakkor a többi csoporthoz képest a magyarországi minta kevésbé elégedett ez utóbbi terület sikerességével. Az iskolával, tanulással való elégedettségre és az elégedettség bejósló tényezőinek feltárására is kitértünk.
Impact of a benzoyl urea insecticide on aquatic macroinvertebrates in ditch mesocosms with and without non-sprayed sections
Authors: Brock Theo C.M. , Roessink Ivo , Belgers J. Dick M. , Bransen Fred , Maund Steve J.
Published: May 2009

The long-term response, including recovery, of aquatic macroinvertebrates to short-term insecticide exposure may be affected by the presence of uncontaminated refuges in the stressed ecosystem. Experimental ditches were used to study the influence of non-sprayed ditch sections regarding the ecotoxicological effects on and the recovery of macroinvertebrates following treatment with the insecticide lufenuron. The treatment regimes differed in the proportion of the ditch (0, 33, 67, and 100% of surface area) that was sprayed to reach a lufenuron concentration of 3 μ/L in the water column of the sprayed ditch section. The magnitude and duration of effects on macroinvertebrates, and on arthropods in particular, were higher when a larger proportion of the ditch was treated. Initially, more pronounced responses were observed for bivoltine and multivoltine insects and macrocrustaceans than for univoltine and semivoltine arthropods. Most macroinvertebrate arthropods showed delayed responses, with maximum treatment-related effects observed two to six weeks after lufenuron application. This latency of effects can be explained by the mode of action of lufenuron, involving inhibition of chitin synthesis, which affects arthropod molting and metamorphosis. The observed effects were short-lived only in those ditches where 33% of the surface area was sprayed. In the ditches where 67 and 100% of the surface area was sprayed, some insects and macrocrustaceans showed long-term effects. In the 100% sprayed ditches in particular, the treatment-related reduction in arthropods resulted in indirect effects, such as an increase in snails, and later in an increase in the ephemeropteran Cloeon dipterum, probably because of an increase in periphyton, and release from competition and predation. Effects that are most likely indirect also were observed for Oligochaeta, Hirudinea, and the flatworm Mesostoma sp.
Comparison of chemical binding to recombinant fathead minnow and human estrogen receptors alpha in whole cell and cell-free binding assays
Authors: Rider Cynthia V. , Hartig Phillip C. , Cardon Mary C. , Wilson Vickie S.
Published: May 2009

Little evidence shows in vivo effects of phthalates on reproductive endpoints in fish. While most of the evidence is negative [24,25], a few studies report in vivo effects of phthalates on estrogen-dependent endpoints. Christiansen et al. found that BBP, but not DBP, induced vitellogenin in rainbow trout at concentrations of 500 and 1,000 mg/kg administered via intraperitoneal injection [26]. Kim et al. found that DEHP elicited potentially antiestrogenic effects in female medaka, as evidenced by decreased vitellogenin levels, decreased gonadal-somatic indices, and immature oocytes in DEHP-treated females as compared to their control counter-parts [27].
Remote Operation of Offshore Gas-Condensate Production
Authors: Ackerman V.L. , Lewright W.K.
Published: May 2009

The Pure Oil Co.'s initial installation in the Vermilion Block 39 Field operates a remote platform approximately 1–3/4 miles distant from a central platform. The remote platform contains three gas-condensate wells and their allied production equipment in conjunction with the require safety and aid to navigation equipment. The production equipment consists of low temperature extraction units with the gas and condensate being measured by orifice meters. Twenty-one temperature and pressure functions are continuously telemetered and recorded. Twelve additional temperature and pressure functions are telemetered on a selective basis and only indicated at the control platform. Twenty-three supervisory control points are provided for operational and safety requirements. A 6700-MC microwave system utilizing three channels for the telemetered and control functions and one voice communication channel provide the connecting link between the remote and control platform. Required power is supplied by diesel driven generators at each platform. This arrangement brought about a problem in frequency control and automatic synchronization of generators.

Selection of equipment and its application was based upon a fundamental requirement of "fail safe" operation with the viewpoint of its application being expanded to encompass a much larger area of operation.

It is believed that this installation will point the way toward means of reducing costs, increasing safety, and increasing efficiency in offshore gas-condensate production.

Introduction

The trend toward semi-attended or unattended production facilities in the oil industry has been gaining momentum during the past two or three years. Even prior to the present "recession," this trend was well established.

The ever rising costs of lease production including supplies replacement parts, salaries, etc., caused the oil industry to seek some means of reducing these operating costs, and further aggravating the situation of increasing costs were decreasing profits.
The Effect of Clay Blocking and Low Permeability on Formation Testing
Authors: Jones F.O. , Neil J.D.
Published: May 2009

The influence of mud filtrate on well productivity was investigated. The particle movement concept of clay blocking was found to be more generally applicable as an explanation of the effect of clays on productivity than the interlamillar swelling concept. It was found that although oil productivity could be recovered to a great extent following clay damage, recovery times may be sufficiently long that potential production could be missed during conventional drill stem testing. A mathematical analysis indicated that the increase in time required to obtain productivity can be attributed to law permeability, low drawdown pressure, deep invasion and decreased mobility of water caused by clay effects.

Introduction

For a number of years it has been suspected that drilling muds occasionally damage the productivity of formations. Workover operations, for instance, have sometimes caused damage. Proved production which was temporarily by-passed while drilling deeper has at times been harmed or lost. Reservoirs have been missed on first wildcats because of negative tests. These productivity losses have been frequently ascribed to damage by mud. Invaded mud filtrate interferes with the flow of oil from the formation and can on occasion affect the matrix itself.

Statistical studies suggested that there was a correlation between length of exposure of a formation to mud and the degree of damage. Mathematical analyses of pressure build-up data indicated that there was a "skin effect" or zone of reduced permeability around some oil wells.

A damaged zone around a well may not only decrease productivity but may possibly even hide the presence of oil or gas. Consequently, it is important to find how the damage is done, how severe and permanent it is, and, using this information, to deduce to what extent the damage interferes with formation testing.

The fact that fresh water could affect certain rocks and reduce permeability was recognized during the early work in core analysis. Later it was discovered by X-ray diffraction analysis that montmorillonite, orbentonite, could admit relatively large quantities of water between inter crystalline layers and expand the crystal.
The Combustion Gas Turbine - Historical Development and Present Day Applications to Natural Gas Pipelines
Authors: Park Tracy S.
Published: May 2009

Introduction

The gas turbine has attained commercial significance as a competitive prime mover only in recent years. Few other mechanisms have had as much time and effort devoted to their development, and with such limited success prior to the present combustion type. Apparently misled by its simplicity, countless inventors have experienced repeated failures in their attempt to achieve a successful machine. It is logical to inquire why a practical design was not evolved during these hundreds of years of experimentation. The plaything of Hero, Newton, comic strip artists, dreamers, jet propulsion enthusiasts, and many sane, capable engineers, has only recently reached its present stage of development. Only a handful of industrial gas turbines are now in service, and the principles of operation are not widely known

The successful development of the gas turbine is closely associated with the utilization of elevated temperatures and a highly efficient air compressor. Most of the progress realized is therefore directly attributable to efforts of metallurgists and aerodynamicists. The main difficulty has been in building a turbine that can develop more power than is consumed by its own air compressors. The superior materials available today permit operation at elevated temperatures, and progress in fluid research has resulted in a highly efficient axial flow compressor. The inherent simplicity of the gas turbine, and its independence of water facilities and complex auxiliaries, ideally adapts it for certain classes of service. Examples are rail locomotives, electric power generators, gas compressor units, and marine applications.

Historical Outline

Current publicity appears to have created the impression among the general public that the gas turbine is an invention of recent origin. To dispel an erroneous conception, it is worthwhile to delve into the general background of this prime mover and observe the antiquity associated with the art.
Strength Of Oil Well Cements And Additives Under High Temperature Well Conditions
Authors: Saunders Calvin D. , Walker Wayne A.
Published: May 2009

Recent tests have shown that the strengths of cement will decrease with increase in temperature and age above a critical temperature. The critical temperature appeared to be approximately 220 degrees to 240 degrees F.

This paper presents results of tests which were designed to determine, if possible, the cause and means for overcoming this strength loss. Various types of cements and additives were evaluated in this investigation. These data are the results of tests made to date in this investigation.

No definite conclusions are drawn at this time, but it appears that by the proper selection of additives for cement, strength loss with age at high temperatures can be either eliminated or considerably lessened.

Introduction

The strength of oil well cement is usually considered to increase with increasing temperature under the normal conditions prevailing in an oil well. Only recently the fact that the strength of the cement decreases rapidly with high temperature and age was brought to the attention of the industry. The data presented in a paper, prepared by the API Mid-Continent District Study Committee on Cementing Practices and Testing of Oil Well Cements, given at the 1954 Spring Meeting of the Mid-Continent District showed that all types of Portland and oil well cements tested had much less strength when cured at 320degrees F than when cured at 200 degrees F. Also this paper contained data showing some cements had a retrogression of strength with time as the cement was cured at 320 degrees F, with some cements losing more than 50 per cent of their one-day strength after 14 days. This paper offered no explanation as to what remedies might be taken to alleviate or eliminate this strength retrogression.
An Analysis of the Linear Displacement of Oil by Gas-Driven Solvent
Authors: Johnson Edward F. , Welge Henry J.
Published: May 2009

A method of calculation is presented for predicting the performance of a solvent extraction process. The process proposed involves the displacement of oil by a liquid solvent which is moved through the reservoir by a driving gas. The gas evaporates solvent at the point of first contact, and condenses the solvent vapor farther downstream. This condensation swells the oil and decreases its viscosity, thus making displacement of the oil easier. It has been predicted theoretically that 100 per cent recovery of oil is possible.

A formula is derived which permits calculation of the minimum solvent requirement to secure complete oil recovery. Also derived are formulas for calculating the average residual oil saturation left when less solvent is used, and the flowing gas-liquid ratios emerging from the porous body. Appropriate material balance equations are presented to provide a check on the correctness of the derivations and the precision of the calculations. The solution of a typical gas-driven solvent problem requires a few hours' time on a medium-speed computing machine.

Curves are given in the paper which illustrate the results obtained in the calculations. The theoretical results compare very favorably with experimental studies made on long cores. For a given quantity of injected solvent and a given throughput of gas in pore volumes, the displacement of oil is not very sensitive either to the pressure level employed, or to the type of sandstone.

Introduction

The recovery of oil by solvent extraction is currently receiving much attention. Part of this interest is no doubt due to the fact that oil recoveries up to 100 per cent may be obtainable in the contacted or swept portions of the reservoir.
A Colorimetric Microwell Method for Determining Bromide Concentrations
Authors: Lepore Brian J. , Barak Phillip
Published: May 2009

Bromide is commonly used as a tracer in studies of water and chemical transport in soil and rock because it is relatively nonreactive with soil and rock constituents and because of its low environmental background concentrations. Based on a largely ignored modification of an American Public Health Association standard colorimetric method for determining Br− using phenol red and chloramine‐T(CT), we have corrected an internal error and recast the technique for use with 96‐well microplates. Furthermore, the addition of thiosulfate to quench the undesirable chlorination reaction as previously published is shown to be unnecessary and even detrimental following the use of NH4+ to produce chloramine from excess Cl species. The method detection limit is 0.11 mg L−1 Br−; negative interference with dissolved organic C can be addressed by either standard additions or solid‐phase extraction with C18 sorbent. By reducing the sample size from 300 to 20 μL, the concentration range can be expanded from 12 mg L−1 Br− to as much as 300 mg L−1 Br−
Gamma‐Radiometric Assessment of Soil Depth across a Landscape Not Measurable Using Electromagnetic Surveys
Authors: Wong M. T. F. , Oliver Y.M. , Robertson M. J.
Published: May 2009

Soil depth affects plant available soil water storage capacity (PAWC). This storage capacity is important for grain yield, deep drainage, and nitrate leaching in dryland environments but is difficult to measure directly on a broad scale. Measurements of ECa provide a means of estimating soil depth at spatial resolution of <50 m when sufficient contrast in conductivity exists between the surface and the root‐impeding subsurface layers. This work was conducted to address the inability of conductivity‐based methods to estimate soil depth in commonly occurring sandy soil over lateritic cemented gravels/rock landscapes as both sandy soils and cemented gravels/rock have similar low conductivities. The gravel/rock layer is naturally enriched with radioisotopes of K, Th, and U. We developed the principle to estimate soil depth based on attenuation of radiation due to the thickness of the soil layer. The method was tested using ground and airborne gamma‐radiometric surveys coupled with soil depth measurements. Site‐specific gamma‐emission was used to calculate component emissions from the soil and gravel/rock layers and in turn soil depth from its theoretical relationship with the component emission data. The root mean square error (RMSE) of soil depth estimates from flown and ground data were 7.9 and 4.9 cm, respectively. The maximum measurable soil depth was 45 cm due to attenuation. Plant available soil water storage capacity measured in the <90 cm soil layer was linearly correlated (r2 = 0.9) with soil depth. This opens the way to use gamma‐radiometry to assess soil depth and PAWC in landscapes with shallow sandy soil over cemented gravels.
Spatial Prediction of Soil Organic Matter Content Using Cokriging with Remotely Sensed Data
Authors: Wu Chunfa , Wu Jiaping , Luo Yongming , Zhang Limin , DeGloria Stephen D.
Published: May 2009

Accurately measuring soil organic matter content (SOM) in paddy fields is important because SOM is one of the key soil properties controlling nutrient budgets in agricultural production systems. Estimation of this soil property at an acceptable level of accuracy is important; especially in the case when SOM exhibits strong spatial dependence and its measurement is a time‐ and labor‐consuming procedure. This study was conducted to evaluate and compare spatial estimation by kriging and cokriging with remotely sensed data to predict SOM using limited available data for a 367‐km2 study area in Haining City, Zhejiang Province, China. Measured SOM ranged from 5.7 to 40.4 g kg−1, with a mean of 19.5 g kg−1 Correlation analysis between the SOM content of 131 soil samples and the corresponding digital number (DN) of six bands (Band 1–5 and Band 7) of Landsat Enhanced Thematic Mapper (ETM) imagery showed that correlation between SOM and DN of Band 1 was the highest (r = −0.587). We used the DN of Band 1 as auxiliary data for the SOM prediction, and used descriptive statistics and the kriging standard deviation (STD) to compare the reliabilities of the predictions. We also used cross‐validation to validate the SOM prediction. Results indicate that cokriging with remotely sensed data was superior to kriging in the case of limited available data and the moderately strong linear relationship between remotely sensed data and SOM content. Remotely sensed data such as Landsat ETM imagery have the potential as useful auxiliary variables for improving the precision and reliability of SOM prediction.
Hydraulic Properties of a Sandy Loam Soil following Spent Drilling Mud Application on Native Prairie
Authors: Zvomuya Francis , Larney Francis J. , DeMaere Paul R. , Olson Andrew F.
Published: May 2009

Water‐based drilling mud (WBM) systems are used by the petroleum industry during drilling of oil and natural gas wells. Provincial regulations in western Canada allow disposal of spent WBM on cropland and sometimes native prairie at low rates. There is concern, however, that application of drilling waste on native prairie in semiarid climates may alter soil properties, which may adversely affect soil biophysical processes and overall ecosystem productivity. This study was initiated to examine the effects of single and multiple applications of differential rates (0, 40, and 80 m3 ha−1) of summer‐applied WBM on hydraulic conductivity (Kψ) and macropore indices. Results from unconfined, steady‐state infiltration measurements taken at −0.03‐ and −0.01‐m supply pressure potentials (ψ) at the soil surface provide evidence of a significant alteration of these hydraulic parameters with excessive (80 m3 ha−1) drilling mud application. Across the ψ range investigated, Kψ measured 5 to 7 wk after a single mud application and the effective water‐transmission macroporosity (θΔψ) calculated using the Kψ decreased by 54 and 61%, respectively, at 80 m3 ha−1 compared with the control (0) and 40 m3 ha−1 rates. Corresponding decreases 5 to 8 wk after a third annual mud application were 62 and 72%. While the rate effect had disappeared 1 yr after the single application, the effect of three annual applications persisted into the following summer. By modifying soil hydrophysical properties, excessive drilling mud applications may adversely affect the soil water balance and alter the plant community structure in this sensitive ecosystem, with important implications on overall biological productivity.
Soil Nitrogen Mineralization and Microbial Biomass Relation, and Nitrogen Conservation in Humid‐Tropics
Authors: Pandey C. B. , Srivastava R. C. , Singh R. K.
Published: May 2009

The reciprocal relationship between microbial biomass C (MB‐C) and net nitrification in the seasonally dry tropics can reduce nitrate (NO3−) leaching losses, and be regarded as a mechanism of N conservation. The objective of the present study was to determine the influence of high seasonally prolonged rainfall on water‐filled pore space (WFPS), net‐nitrification rates (NNR), net‐ammonification rates (NAR), pool sizes of NH4+–N and NO3−–N, and MB‐C in three major land‐use systems (moist‐evergreen, semi‐evergreen forests, and home garden) in the equatorial humid tropical climate of South Andaman, India. Soil properties were examined to determine a mechanism of N conservation in the humid tropical soils. Across the land use systems, WFPS ranged from 68 to 84% during the wet season and 25 to 47% during wet season dry spells (48–72 h after wet season high rainfall). The rate of net‐nitrification and NO3−–N pool declined 10 to 17 times and 4 to 6 times, respectively during the high rainfall wet season in all the land use systems compared with wet season dry spells. On the contrary, ammonification rate and NH4+–N pool increased 7 to 34 times and 2 to 3 times, respectively during the wet season across land use systems compared with the wet season dry spell. Microbial biomass C was positively correlated with the NNR, but it was inversely correlated with the NH4+–N pool. The above observations suggest that NO3− N is likely reduced to NH4+ via a dissimilatory pathway during rainy periods (anaerobic conditions), which conserves N in the plant available form (NH4+) in the soils of the humid tropics.
Using Complex Networks to Model Two‐ and Three‐Dimensional Soil Porous Architecture
Authors: Mooney Sacha Jon , Korošak Dean
Published: May 2009

The ability to quantify three dimensional (3‐D) soil porous architecture is a key requirement in the advanced understanding of soil functioning. Recent developments in the visualization of soil structure using tools such as x‐ray Computed Tomography (CT) provide new opportunities for pore‐scale modeling. Here we apply a novel complex network approach to examine soil pore architecture in both two (2‐D) and three dimensions (3‐D). Using images of soil structure obtained by x‐ray CT, we constructed and successfully validated a complex network derived from a simple measure for network links between two pores in 2‐D. We were able to illustrate that the soil comprised a spatially embedded scale‐free network characterized by a power‐law degree distribution. Computation of the degree dependent clustering coefficient of the constructed networks showed the hierarchical organization of the soil pore architecture. Finally, we derived an algorithm to generate a soil structure model built on the underlying scale‐free network which was in close agreement with an actual 3‐D reconstructed soil structure. Considering the soil system as a complex network with scale‐free properties is likely to have important consequences for the further understanding of function, in particular transport in soils.
Effect of Charcoal Quantity on Microbial Biomass and Activity in Temperate Soils
Authors: Kolb Simone E. , Fermanich Kevin J. , Dornbush Mathew E.
Published: May 2009

Wildfire‐produced charcoal is a common component of soils, affecting a range of important abiotic and biotic soil processes. Our ability to predict the effects of charcoal addition to soil is currently limited, however, by our understanding of how charcoal affects the soil microbial community mediating many of these processes. This study sought to improve our understanding of the relationship between charcoal addition and soil microbial biomass and activity among temperate soils. Charcoal was added to four distinct temperate soils, a Mollisol, an Alfisol, an Entisol, and a Spodosol, at five application levels ranging from 0 to 0.1 kg charcoal kg−1 soil, and incubated at 25°C with measurements at approximately 0, 1.5, and 3 mo. We hypothesized that microbial biomass and activity would increase with increasing charcoal application in all soils, but the relative magnitude of the response would depend on the texture and fertility of each soil. As hypothesized, microbial biomass and activity and Bray P increased significantly with increasing charcoal application, while extractable N decreased. The coniferous forest soil provided a notable exception to the general patterns of N availability, having the highest total extractable N at the highest charcoal application level. Our results suggest that charcoal additions affected microbial biomass, microbial activity, and nutrient availability in relatively similar ways in all four soils that we studied, suggesting considerable predictability in response to charcoal application. Differences in the magnitude of the microbial response, however, appeared dependent on differences in nutrient availability among soils.
The Maya Footprint: Soil Resources of Chunchucmil, Yucatán, Mexico
Authors: Sweetwood Ryan V. , Terry Richard E. , Beach Timothy , Dahlin Bruce H. , Hixson David
Published: May 2009

This study explored and characterized soil physical and chemical properties to determine how the ancient Maya of Chunchucmil, Yucatán, Mexico, fed themselves. Our objectives were to examine the soil resources and the areas of agricultural importance surrounding Chunchucmil and to search for evidence of agricultural intensification of soils by night soil and charcoal amendments. The C isotopic signature of ancient C4 crops was not detected, suggesting that either maize (Zea mays L.) was not extensively produced or that the mix of native C3 and C4 plants in the savanna hid the signature. There were no soil chemical or biomarker evidences of ancient agricultural intensification, suggesting that ancient agriculture was mainly based on shifting cultivation and arboriculture at Chunchucmil. Concentrations of black carbon, Ca, P, K, Mg, and organic C within urban and rural settlements were enhanced, but probably by incidental human activities. We estimate that the land requirement to sustain the population of Chunchucmil at its height would have been greater than the available resources based on traditional agricultural methods. We cannot ignore the possibilities of intensification techniques, like intensive weeding, watering, and organic fertilizers that would have left no or only modestly elevated major elements. But it is probable that the ancient Maya of Chunchucmil traded marine and estuary products from the Gulf Coast and other high‐value trade items for imported agricultural products.
Influence of Root Exudates of Watermelon on Fusarium oxysporum f. sp. niveum
Authors: Wu Hong-sheng , Liu Dong-yang , Ling Ning , Bao Wei , Ying Rong-rong , Shen Qi-rong
Published: May 2009

Watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai var. lanatus] production in the same field without rotation of crops leads to disease buildup and poor yields. The purpose of this research was to evaluate the influences of root exudates produced by watermelon cultivars susceptible or resistant to the pathogen Fusarium oxysporum f. sp. niveum (FON). At low concentrations of root exudates (<50 mg L−1), the susceptible cultivar stimulated the growth of FON but the resistant cultivars inhibited FON at high concentration (200 mg L−1). Mycotoxin production was increased more in the presence of exudates from susceptible than resistant cultivars and after flowering than before flowering. Activities of enzymes (protease, pectinase, cellulose, and amylase) were stimulated more in resistant than susceptible cultivars by FON. Also, there were higher ratios of antifungal phenolic acids (p‐hydroxybenzoic, phthalic, gallic, coumaric, cinnamic, ferulic, salicylic, and sinamic acids) to fungus‐stimulating phenolic acids (vanillic and syringic acids) in resistant cultivars than in susceptible ones both before and after flowering. Breeding of resistant cultivars containing more antifungal agents is a strategy that, if pursued, could lead to a reduction in the occurrence of watermelon wilt disease, especially when rotation of crops is not possible.
The Dielectric Response of the Tropical Hawaiian Mars Soil Simulant JSC Mars‐1
Authors: Robinson David A. , Jones Scott B. , Blonquist J. Mark , Heinse Robert , Lebron Inma , Doyle Timothy E.
Published: May 2009

The observation of low dielectric values <2, consistent with the bright areas of the surface of Mars, is completely counter to expectation for soils dominated by mafic minerals, especially Fe minerals and pyroxenes that tend to have dielectric values two to three times higher than quartz, which has a value of 4.7. To this day, this observation has not been explained. The recent success of the Phoenix lander in locating water on Mars, however, is renewing interest in the use of sensors to determine Martian soil properties. We took measurements on the Hawaiian JSC Mars‐1 soil simulant, considered to reflect the properties of the soils of the bright regions of Mars. Our objective was to determine if soil structure and dielectric phase configuration could account for low dielectric responses. We discovered that low dielectric values can be reconciled with mafic, Fe‐bearing silicate mineralogy due to the presence of a palagonite structure with internal porosity. Furthermore, dielectric response as a function of water content is startlingly lower than standard soil calibration equations from Earth, meaning that the application of these equations may significantly underestimate water content determined from dielectric measurements—not because of “bound water,” but because of the altered dielectric phase configuration due to the palagonite internal pore structure. The implications of this finding for future planetary missions are that all sensors relying on interpreting soil properties from measurements of bulk soil electrical, thermal, or dielectric properties will be similarly affected in the presence of materials with internal porosity.
Does Physical Protection of Soil Organic Matter Attenuate Temperature Sensitivity?
Authors: Plante Alain F. , Six Johan , Paul Eldor A. , Conant Richard T.
Published: May 2009

Global climate change may induce accelerated soil organic matter (SOM) decomposition through increased soil temperature, and thus impact the C balance in soils. We hypothesized that compartmentalization of substrates and decomposers in the soil matrix would decrease SOM sensitivity to temperature. We tested our hypothesis with three short‐term laboratory incubations with differing physical protection treatments conducted at different temperatures. Overall, CO2 efflux increased with temperature, but responses among physical protection treatments were not consistently different. Similar respiration quotient (Q10) values across physical protection treatments did not support our original hypothesis that the largest Q10 values would be observed in the treatment with the least physical protection. Compartmentalization of substrates and decomposers is known to reduce the decomposability of otherwise labile material, but the hypothesized attenuation of temperature sensitivity was not detected, and thus the sensitivity is probably driven by the thermodynamics of biochemical reactions as expressed by Arrhenius‐type equations.
Conflict Management in Preventing Negative Effects of Change
Authors: Robstad Andersen Gunn
Published: May 2009

Organizational change may involve an increase in work stressors and an impaired social
working climate. This chapter presents a review of such potential negative effects, and proposes
constructive conflict management to be a beneficial way of dealing with them. It is argued that a
managerial focus on the ‘soft sides’ of the organization is an important prerequisite for a successful
change process.
The Importance of Healthy Organizational Change Processes
Authors: Danielsen Tvedt Sturle
Published: May 2009

The present chapter treats the subject of healthy change processes and investigates their role in
organizational change. Based on observations in the research literature of the challenges inherent in
organizational change and own empirical studies, a model is presented linking the comparative
contributions of organizational change and change processes to parameters of the psychosocial work
environment. The model takes as its point of departure that change can be treated as an overall force
which is associated in a general way with certain effects for the psychosocial work environment,
independent of the change content of any given change effort. Further, a conceptualization of the healthy
change process is presented comprising five dimensions: Awareness of norms, awareness of diversity,
leader availability, constructive conflicts, and role clarification. These different dimensions are then
discussed in terms of their individual contributions to the psychosocial work environment of
organizations undergoing change. The chapter concludes with some lessons as to what a healthy change
process can – and cannot hope to provide.
The Riemann zeta-function and moment conjectures from Random Matrix Theory
Authors: Steuding Jörn
Published: May 2009

On the basis of the Random Matrix Theory-model several interesting conjectures for the Riemann zeta-function were made during the recent past, in particular, asymptotic formulae for the 2kth continuous and discrete moments of the zeta-function on the critical line, $$
\frac{1}
{T}\int\limits_0^T {|\zeta (\tfrac{1}
{2} + it)|^{2k} dt} and \frac{1}
{{N(T)}}\sum\limits_{0 < \gamma \leqslant {\rm T}} {|\zeta (\tfrac{1}
{2} + i(\gamma + \tfrac{\alpha }
{L}))|^{2k} }
$$, by Conrey, Keating et al. and Hughes, respectively. These conjectures are known to be true only for a few values of k and, even under assumption of the Riemann hypothesis, estimates of the expected order of magnitude are only proved for a limited range of k. We put the discrete moment for k = 1, 2 in relation with the corresponding continuous moment for the derivative of Hardy’s Z-function. This leads to upper bounds for the discrete moments which are off the predicted order by a factor of log T.
Chosen Problems of Road Accidents Analyses in Poland
Authors: Kisilowski Jerzy , Zalewski Jarosław
Published: May 2009

Chosen Problems of Road Accidents Analyses in Poland

This article offers classification of car collisions from the point of view of the most frequent accidents and crash tests. The most important problems are the consequences of incomplete control of a car. The article focuses on the safety of road traffic in Poland and presents an attempt to analyze the causes of most frequent collisions and their consequences. It gives statistical data and attempts to analyze the level of road traffic safety. Some important indicators are shown here to compare the situation in France and Poland, which enabled verification of some opinions about road traffic safety in Poland.
Preventive Maintenance with Imperfect Repairs of a System with Redundant Objects
Authors: Okulewicz Józef , Salamonowicz Tadeusz
Published: May 2009

Preventive Maintenance with Imperfect Repairs of a System with Redundant Objects

An object ability to realise tasks may be restored by repairing only failed components. This is called imperfect repair, as the object is not as good as new after such a repair. Preventive replacement is an example of imperfect repair as well. The advantage of such maintenance is that it enables controlling a reliability level of a system. Sets of objects' components that should be replaced are derived on a basis of statistical diagnosing with use of data about components failures. The acceptable level of a failure risk while executing transportation tasks has been taken as a criterion of choosing elements to be replaced. An algorithm of selecting components for preventive replacement has been developed. It was shown that a level of system reliability could be controlled by changing an order of a quintile function in coordination and a number of redundant objects. A computer simulation model of the system was used to illustrate derived dependencies.
The Man - Machine Type Systems Modeling Approach
Authors: Smalko Zbigniew , Szpytko Janusz
Published: May 2009

The Man - Machine Type Systems Modeling Approach

The subject of this paper deals with selected usable characteristics of man - machine systems described by the selected basic attributes. The paper is describing also major objectives of safety engineering, based on the system approach, understanding the structure of safety management system, including the human factor, and all interrelationships between the system components. The part of the paper is example of safety engineering implementations in practice.
Rbf Neural Networks for Function Approximation in Dynamic Modelling
Authors: Nedbalek Jakub
Published: May 2009

Rbf Neural Networks for Function Approximation in Dynamic Modelling

The paper demonstrates the comparison of Monte Carlo simulation algorithm with neural network enhancement in the reliability case study. With regard to process dynamics, we attempt to evaluate the tank system unreliability related to the initiative input parameters setting. The neural network is used in equation coefficients calculation, which is executed in each transient state. Due to the neural networks, for some of the initial component settings we can achieve the results of computation faster than in classical way of coefficients calculating and substituting into the equation.
Aging Processes as a Primary Aspect of Predicting Reliability and Life of Aeronautical Hardware
Authors: Żurek Józef , Niezgoda Tadeusz , Zieja Mariusz
Published: May 2009

Aging Processes as a Primary Aspect of Predicting Reliability and Life of Aeronautical Hardware

The forecasting of reliability and life of aeronautical hardware requires recognition of many and various destructive processes that deteriorate the health/maintenance status thereof. The aging of technical components of aircraft as an armament system proves of outstanding significance to reliability and safety of the whole system. The aging process is usually induced by many and various factors, just to mention mechanical, biological, climatic, or chemical ones. The aging is an irreversible process and considerably affects (i.e. Reduces) reliability and life of aeronautical equipment.
Assessment of the Level of Undesirable Actions of People Involved in Road Transport Systems and their Environments.
Authors: Woropay Maciej , Bojar Piotr , Szubartowski Mirosław
Published: May 2009

Assessment of the Level of Undesirable Actions of People Involved in Road Transport Systems and their Environments.

Road transport systems are socio-technical systems of the type Human - Technical object- Environment . In these systems hazards can be caused by: the man C, the technical object OT, and influence of the environment on the technical object and people who are present in the system and its environment. The authors of the paper make an attempt to evaluate the level of threats resulting from intended or not intended actions of people situated in this environment.
Reduced platelet aggregability and thromboxane release after rebleeding in patients with subarachnoid hemorrhage
Authors: Juvela Seppo , Kaste Marrku
Published: May 2009

✓ Serial blood samples were obtained from 80 patients with subarachnoid hemorrhage (SAH) to study adenosine diphosphate-induced platelet aggregation and associated thromboxane B2 release. The goal of the investigation was to detect whether reduced platelet function is involved in rebleeds. Seventeen patients (21%) suffered a rebleed, six of those experiencing their first rebleed within 24 hours after SAH. Therefore, most platelet function studies were performed after rebleeds. Thromboxane release was lower in patients with rebleeds than in the others, both before and after rebleeding, although statistical significance was reached only in samples collected after rebleeds. Patients rebleeding within 24 hours after SAH had lower platelet aggregability (p = 0.037) than patients without a rebleed in the samples taken within 3 days after SAH. The results suggest that reduced platelet aggregability and thromboxane release are involved in rebleeds following primary SAH.