bluuebunny/crossref_metadata_2025 huggingface dataset:
Significance of DOM in the translocation of cations and acidity in acid forest soils
Authors: Guggenberger Georg , Kaiser Klaus
Published: December 2011

We estimated the contribution of dissolved organic matter (DOM) to cation leaching and the translocation of acidity in three acid forest soils. The analysis was based on monitored (2 years) concentrations of dissolved organic carbon (DOC) in the field, measured total acidities of DOM, and measured as well as predicted weighted mean dissociation constants of the organic acids. Although the forest floor solutions were strongly acidic (pH 3.47–4.10), a considerable proportion of the organic acids was dissociated and organic anions represented 22–40% of the total anions in the mineral soil input. The flux of DOM‐associated exchangeable protons from the forest floor to the mineral soil ranged from 0.35 (Wülfersreuth) to 3.72 (Hohe Matzen) kmol ha−1 yr−1. In the subsoil, this organic acidity may be neutralized by microbial decomposition of the organic acids, but a part of the hydrogen ions may dissociate and contribute to acidification of the soil solution and to weathering processes. Due to the pronounced retention of DOM in the mineral subsoil horizons, the contribution of DOM to the output of cations and acidity from the soil is much lower than in the surface horizons but still significant.?
Release of hydroxyl ions during specific adsorption of chloride by variable‐charge soils
Authors: Wang J. H. , Yu T. R.
Published: December 2011

The release of hydroxyl ions during specific adsorption of chloride by variable‐charge soils of China was studied by comparing the difference in pH of the suspension between a HCl‐treated system and a HNO3−treated system. A difference occurred only for the variablecharge soils, but not for the permanent‐charge soil. The release of OH− ions decreased upon removal of free iron oxides. The quantity of released OH was larger for electrodialyzed soils than that for untreated soils. It was less than 10% of the amount of Cl added. The OH/CI ratioincreased with increasing addition of HCl, suggesting that more OH relative to H2O was replaced by CI.
Salts and acids as determinants of the solution composition of acidic forest soils — anion effects
Authors: Kaiser Klaus , Kaupenjohann Martin
Published: December 2011

The study aimed at evaluating whether salt‐induced mobilization of acidity may be modified by the type of anion. For this purpose, the effects of different neutral salts on the solution composition of acid soils were investigated. The results were compared with those of the addition of acids. Two topsoil (E and A) and two subsoil horizons (Bs and Bw) were treated with NaCl, Na2SO4, MgCl2, MgSO4, HCl, and H2SO4 at concentrations ranging from 0 to 10 mmol dm−3.

With increasing inputs of Cl− the pH of the equilibrium soil solution dropped, the concentrations of Al and Ca increased, and the molar Ca/(Al3+ + AlOH2+ + Al(OH)2+) ratios decreased. These effects were the least pronounced when NaCl was added and the most at the HCl treatments. According to the release of acidity, the topsoils were more sensitive for salt‐induced soil solution acidification whereas on base of the molar Ca/(Al3+ + AlOH2+ + Al(OH)2+) ratios, the salt effect seems to be more important for the subsoils.

Addition of S042− salts and H2SO4 induced higher pH and lower Al concentrations than the corresponding Cl− treatments due to the SO42− sorption, especially in the subsoils. The Ca/(Al3+ + AlOH2+ + Al(OH)2+) ratios were higher than those of the corresponding Cl− treatments. In subsoils even after H2SO4 additions these ratios were not higher than those of the NaCl treatments.

The results indicate (I) that speculation about the effects of episodic salt concentrations enhancement on soil solution acidification not only need to consider the ionic strength and the cation type but also the anion type, (II) that salt‐induced soil solution composition may be more crucial in subsoils than in topsoils, and (III) that in acid soils ongoing input of HNO3 due to the precipitation load may induce an even more acidic soil solution than the inputs of H2SO4 of the last decade.
Quantitative determination of minerals in acid forest soils of granite
Authors: Fichter Jörg , Bonnaud Pascal , Turpault Marie‐Pierre , Ranger Jacques
Published: December 2011

A procedure for quantifying minerals in particle size fractions of fine earth (< 2 mm) is presented. Mineral fractions of the acid forest soils are characterised by various transition products. Transitional minerals between illite and vermiculite or smectite, polyhydroxy‐Al polymers interlayered in smectite and vermiculite, as well as poorly crystalline compounds are present. Normative calculations with standard minerals, generally applied to rocks, cannot be used to quantify precisely minerals of these soil samples. Conventional qualitative and quantitative chemical analyses are therefore completed by microanalyses of well‐identifiable minerals. The calculation procedure is based mainly on a system of simultaneous linear equations. These are set up from the chemical contents of a particle size fraction on the one hand and from the corresponding element contents of single minerals on the other hand. The contribution of single minerals to overall parameters can be calculated by programmed algorithms. The methodology was adjusted to different particle size fractions.
Land‐use effects on organic carbon, nitrogen, and sulphur concentrations in macroaggregates of differently textured Brazilian oxisols
Authors: Lilienfein Juliane , Wilcke Wolfgang , Neufeldt Henry , Ayarza Miguel A. , Zech Wolfgang
Published: December 2011

The objective of this study was to assess the influence of land use on soil aggregate size distribution and the consequences for organic C, N, and S concentrations in bulk soil and macroaggregates. The properties of a loamy and a clayey Oxisol used for continuous cropping, pasture and reforestation were compared with those of the native savannah (“Cerrado”). We measured aggregate size fractionation, C, N, and S concentrations in bulk soil, small (0.25–2 mm, SMA), and large macroaggregates (2–8 mm, LMA), and carried out a mineralization experiment with intact and crushed LMA. The aggregate size distribution of pastures was not different from native Cerrado. Reforestation and plowing caused higher percentages of smaller aggregates which was more pronounced in the loamy than in the clayey soil. Total concentrations of C, N, and S were higher in the clayey (C: 21.5–23.3 g kg−1; N: 1.2–1.4 g kg−1; S: 178–213 mg kg−1) than in the loamy soil (C: 7.8–10.3 g kg−1; N 0.5–0.7 g kg−1; S: 87–132 mg kg−1). LMA of the loamy soil had higher C, N, and S concentrations than the bulk soil. SMA and both macroaggregate fractions of the clayey soil did not differ from the bulk soil. 71 % of potentially mineralizable N in LMA of the loamy soil were only mineralized after aggregate disruption. In contrast, there were only small differences between crushed and intact LMA of the clayey soil. Therefore, we considered conventional tillage suitable for clayey soils. The loamy soil would require a more soil conserving system like no‐till or crop‐pasture rotation to improve sustainability.
Effects of selected cations and anions on pK‐0.5pCa values for a Mn oxide system
Authors: Wang F. L. , Yu T. R. , Huang P. M.
Published: December 2011

We studied the relative influences of Mn2+, Al3+ NO3− and SO42− on the K‐Ca relationship, as expressed by a pK‐0.5pCa value, in a Mn oxide suspension system using a double indicator electrode technique. With an increase in the quantity of solution Mn2+ and Al3+ in the system, Mn2+ ions showed a stronger effect than Al3+ on increasing pK‐0.5pCa values, though this was not the case when the amount of the cations added was low. The stronger effect of Mn2+ on the K‐Ca relationship was attributed to stronger specific adsorption of the Mn2+ ion on the Mn oxide as compared with Al3+. When K+ and Ca2+ were added after the addition of Mn2+ and Al3+, activities of K and Ca in equilibrium solution were higher than those when K+ and Ca2+ were added first, indicating that the exchange reaction of the cations on the Mn oxide was not fully reversible. Compared to NO3− added systems, the pK‐0.5pCa values for SO42− added systems were lower when the initial K/Ca molar ratios were 0.5 and 2. This effect of SO42− on the pK‐0.5pCa values was also related to the quantity of Ca ions in the system since no significant difference in pK‐0.5pCa values was observed between the SO42− and NO3− added systems when the K/Ca molar ratio was 8. The present results revealed that both cationic and anionic environments had a profound influence on the adsorption of K and Ca and, thus, the pK‐0.5pCa values in a Mn oxide system. The findings of this study help attain a better understanding of the chemistry of K in soils, particularly those with variable charge.
Maßstabsabhängige räumliche Variabilität mikrobieller Bodenkenngrößen in einem Buchenwald
Authors: Stork Rudolf , Dilly Oliver
Published: December 2011

Die räumliche Variabilität des Gehaltes an mikrobieller Biomasse (Cmic), der mikrobiellen Respirationsrate (Basalatmung) und des metabolischen Quotienten (qCO2) wurde in sandigen Braunerden und Parabraunerden unter Buchenwald in Norddeutschland untersucht. Die höchste Variabilität der mikrobiellen Kenngrößen und damit der Abstand, ab dem die räumliche Unabhängigkeit der Proben gewährleistet war, wurde bei etwa 10 m erreicht und in Zusammenhang mit räumlicher Hierarchie diskutiert. Strukturelle Unterschiede zwischen dem Maßstab des 10 m‐ und des 50 m‐Rasters (Ah‐Horizont) wurden durch einen Bruch der Korrelationen von Cmic−Gehalt und der Gehalte an Corg, pflanzenverfügbarem Ca, Mg, K sowie Nt angezeigt. Hohe Cmic−Gehalte korrespondierten mit hohen Corg−Gehalten in unmittelbarer Stammnähe und in Ökotonbereichen wie Waldrändern und Lichtungen. Der qCO2 stieg nicht generell mit abnehmendem pH‐Wert. Hohe H+‐Konzentration und hoher Corg−Gehalt in der Streuauflage des Stammfußbereiches ließen sich mit verringerter mikrobieller Zersetzungsleistung erklären. Hohe Anteile an gegenüber niedrigen pH‐Werten toleranten Mikroorganismen, die leicht zersetzbares Substrat bevorzugen, scheinen im Stammfußbereich vorzuherrschen.
Intracellular and extracellular enzyme activity in soil with reference to elemental cycling
Authors: Duly Oliver , Nannipieri Paolo
Published: December 2011

Enzyme activities play an important role for the transformation of elements and compounds in soil and, thus, were extensively analyzed for more than 4 decades. The activity of any enzyme in soil may not only be controlled by active organisms. Substantial parts of ‘extracellular’ enzymes may be stabilized by abiotic soil components maintaining their activity. Methods to discriminate the source of enzyme activity were summarized with emphasis on the approach plotting enzyme activity versus a feature integrating the microbial biomass after the addition of glucose and nitrate. Considering the quotient between enzyme activity and microbial biomass content, protease activity will be discussed with reference to nitrogen transformation in soils.
Abschätzung erhöhter Bodenbelastungen mit polychlorierten Dibenzo‐p‐dioxinen und Dibenzofuranen bei der bodenkundlichen Geländeaufnahme
Authors: Lenz Harald , Bächle Herbert , Schneider Jörg , Thater Michael , Stahr Karl
Published: December 2011

Unsystematisch verteilte Bodenbelastungen mit polychlorierten Dibenzo‐p‐dioxinen und Dibenzofuranen (PCDD/PCDF) waren Anlaß für die Durchführung einer Stadtbodenkartierung in Rheinfelden (Baden). Diese teilweise sehr hohen Belastungen ließen sich nicht allein durch atmosphärischen Eintrag aus ansässigen Industriebetrieben erklären. Zur Ermittlung des Ausmaßes der Bodenbelastungen wurde als Methode die fallbezogene Stadtbodenkartierung gewählt.

Der Stadtbodenkartierung lag nach Voruntersuchungen als Arbeitshypothese zugrunde, daß in Rheinfelden erhöhte PCDD/PCDF‐Bodenbelastungen an erkennbare Partikel gebunden im Boden vorliegen und deshalb durch eine bodenkundliche Geländeaufnahme erfaßbar sind.

An etwa 3700 Bohrpunkten erfolgte eine Bodenansprache. Durch die flächendeckende, parzellenscharfe Kartierung konnten (hoch)bela‐stete von wenig bzw. unbelasteten Bereichen abgegrenzt werden. Es wurden etwa 720 Bodenproben entnommen und auf Schwermetalle untersucht. An 140 Proben wurden die PCDD/PCDF‐Gehalte bestimmt. Durch die Analytik wurde bestätigt, daß im speziellen Falle Rheinfeldens PCDD/PCDF‐Belastungen über 100 ng I‐TFQ/kg nahezu ausschließlich in den als stark anthropogen gestört eingestuften Böden zu finden waren, Diese Böden waren erkennbar mit solchen Beimengungen verunreinigt, die auf erhöhte PCDD/PCDF‐Gehalte hinweisen und durch die Geländeaufnahme erfaßbar sind.

Eine eindeutige Beziehung zwischen angenommenen Leitparametern (Ba, Hg. Pb) und PCDD/PCDF konnte nicht nachgewiesen werden.

Die Methode einer solchen bclastungsfallspezifisuh modifizierten Stadtbodenkartierung ist grundsätzlich für die Erkundung aller flä‐chenhaften Bodenbelastungen geeignet, die an feldbodenkundliche Merkmale gekoppelt sind. Sie kann im Einzelfall eine effiziente und kostensparende Erkundungsmethode darstellen.
Polychlorinated biphenyls (PCBs) in bulk soil and particle size separates of soils in a rural community
Authors: Wilcke Wolfgang , Zech Wolfgang
Published: December 2011

In a rural community (Stephanskirchen, Southern Germany) situated near a waste incineration plant six A horizons were sampled to determine 14 polychlorinated biphenyls (PCBs) in bulk soil and particle size separates (clay, silt, fine and coarse sand) and to test the suitability of alkaline saponification for PCB extraction. The PCB concentrations were higher in alkaline saponification extracts than in Soxhlet extracts. However, the extraction efficiency of up to fourfold chlorinated PCBs was lower and more than sevenfold chlorinated PCBs were destroyed. Nevertheless, alkaline saponification was suitable to determine the indicator congeners 28, 52, 101, 138, 152, and 180. The sum of the PCB concentrations ranged from 8.4 to 59.5 μg kg−1 which was as high as in soils of big cities. However, the concentrations did not reach the threshold value for agricultural purposes of 200 μg kg−1 as proposed in literature for the sum of the six indicator congeners. The hexachlorinated PCBs 138 and 153 were the most abundant (together > 50% in all samples) whereas PCB 1 could not be detected in any sample. On the average, PCB concentrations increased as particle size decreased. When normalized to Corg, however, the fine sand fraction had the highest PCB concentrations. A slight decrease of lower chlorinated PCBs as particle size decreased indicated an increasing state of degradation. The PCB compositions in the emissions of a comparable waste incineration plant (Bamberg, Bavaria) and in Stephanskirchen soils differed markedly. Therefore, we did not get any indications that waste incineration was a main source of PCBs in the examined soils. Instead, higher chlorinated technical PCB mixtures such as Clophen A 60 or Aroclor 1260 may be the most important sources.
Schwermetalle in Oberböden des Warthetals unter städtischem Einfluß
Authors: Lewandowski Piotr , Burghardt Wolfgang , Ilnicki Piotr
Published: December 2011

Im städtischen Bereich der Stadt Poznan wurde die Schwermetallkontamination der Böden im Tal der Warthe untersucht. Aus fünf Talquerschnitten wurden 87 Proben der obersten Bodenschichten entnommen. Neben allgemeinen Bodenkennwerten wurden Gehalte an Arsen, Barium, Blei, Cadmium, Chrom, Eisen, Kupfer, Mangan, Phosphat und Zink bestimmt. Die Talböden weisen keine hohen Gehalte an Schwermetallen auf. Nur unterhalb von Abwassereinleitungen befinden sich erhöhte Gehalte an Blei und Cadmium. Eine starke Bodenkontamination wurde im Bereich der Altstadt gemessen. Dort wurden die höchsten Gehalte an Blei, Kupfer und Zink gefunden.

Die Verteilung von Schwermetallen in Flußsedimenten weist darauf hin, daß als Ursache das Einbringen von Abwässern angesehen werden muß. Korrelationen zwischen den Elementgehalten und weiteren Bodenkennwerten (pH, Ton‐ und P‐Gehalt, C/N‐Verhältnis) werden vorgestellt.
Measuring interlayer potassium release rates from soil materials. I. Critical evaluation on the use of resin and other batch procedures for determining kinetic data
Authors: Springob Günther , Richter Jörg
Published: December 2011

Laboratory procedures are evaluated for their principal suitability to derive unbiased kinetic data of interlayer K release (days to weeks, Luvisol ‘Ohlendorf’, loess, Ap horizon). The final intention is to relate K release rates to their main governing soil environmental variables rather than to conventional procedural standards. Of actual interest are technical aspects of quantifying the influence of solute K (CK), which is considered to be the most important among those variables. The relevant range is that of a few μM K, similar to the rhizosphere of plants where diffusion‐controlled, non‐destructive K release is thought to be of importance. Tested non‐resin batch techniques, e.g. the time dependent shift of K‐Ca exchange isotherms, are considered to be unsuitable because the derived release rates were markedly biased by shaking the suspensions. Generally, the batch technique just showed that additional proton induced release of nonexchangeable K (Knex) is negligible above pH 4. Ca‐resin procedures extracted considerable amounts of Knex but most of it had to be attributed to the addition of fresh (K‐free) exchange solution rather than to the presence of the resins. Further, an active regulation of CK in the intended range was only hardly possible via the resin/soil ratio but was inexact and only achieved with inacceptable effort. Further modifications, e.g. containing the resins in dialysis tubes, improved the technique but did not eliminate the main problems: Ca‐resin does not act as a real sink for K. H‐resins did act as a sink but, due to other constraints, are also rejected: CK is too low (< 1 μM, no effective regulation possible) and the pH of the suspension steadily declines (< 3 after one week). The one promising procedure among those tested was a continuous (non‐resin) percolation technique (> 900 h) which permitted a flexible regulation of CK by the percolation rate.
Geo‐ecological soil features and the vegetation pattern in an arid dune area in the Northern Negev, Israel
Authors: Beyer Lothar , Tielbörger Katja , Blume Hans‐P. , Pfisterer Ulrich , Pingpank Kristina , Podlech Dieter
Published: December 2011

Soils are suggested to be an important factor influencing the vegetation pattern. In order to prove this hypothesis in an arid and sandy Negev ecosystem of longitudinal dunes and interdune corridors near Nizzana, Israel, the distribution of soil units and plant communities were compared on a very small‐distance level. The Nizzana site has a size of nearly 100 ha. 250 soil pits with 3–5 horizons were mapped and sampled within the soil geographical monitoring. Soil water capacity and cation exchange capacity were estimated from the field data. In addition 176 plots of 100 m2 were established around the soil pits with emphasis on plants, coveting the environmental gradient across the dune ridges. Plant mapping plots were arranged into groups with the same dominating perennial species and a key for the vegetation mapping was developed. In the investigated desert site topography, soil surface crust, soil texture and salt content partly can explain the distribution of plant communities. A soil classification proposal is based on these parameters and is a useful tool to indicate correlations between soil units and the vegetation pattern. Nevertheless, dependent on topography and surface and/or subsurface water flow as well as the occurrence of “fertile islands” the moisture and nutrient regimes influence the vegetation pattern with respect to plant growth to a greater extent than the soils themselves.
Dust characteristics and source‐sink relations in eastern West Africa (SW‐Niger and Benin) and South America (Argentinean Pampas)
Authors: Ramsperger Barbara , Herrmann Ludger , Stahr Karl
Published: December 2011

In order to quantify dust input and to describe its characteristics under different environmental conditions, and to get information on source‐sink relation, dust was collected monthly with bulk deposition samplers (open bucket type) in 2 and 4 m height over a 2—3 years period at different sites in West Africa (SW‐Niger and Benin) and in the semi‐arid Argentinean Pampas.

Dust input, mineralogy (bulk and clay), chemical properties including total element content and particle‐size distribution showed a clear seasonal pattern in eastern West Africa. Far‐transported Saharan dust in the dry season could be distinguished from local material transported in the rainy season. In Argentina, high sand content of the samples pointed to an important participation of local components in the collected material. This was supported by higher contents of seaborne salts at the coastal sites, and the highest amounts of collected dust at the site of highest wind velocities. Due to the lack of seasonal differences in dust amount and its characteristics, and the aeolian genesis of the Pampas soils, a separation of local material and long‐range dust was not possible.
Reduction of herbicide contamination in flowing waters
Authors: Frede Hans‐Georg , Fischer Peter , Bach Martin
Published: December 2011

A brief survey of potential pathways of herbicide transport in flowing waters is given. For a small watershed in Hesse (central Germany) during 4 spraying periods (spring and autumn 1995 and 1996) all point and non‐point sources were measured. It was proved that faulty spray practice occurred in 60% of 260 applications. However this source caused no evident herbicide contamination in running waters. More than 90% of the total herbicide load has been detected as point sources originating from the 40 farms connected to a sewage plant. Compared to these point sources, the pesticide pollution originating from runoff and subsurface drainage was not significant. An example is given describing how advisory measures in pesticide handling can reduce the loads by 80%.
New quality of assessment of microbial diversity in arable soils using molecular and biochemical methods
Authors: Schloter Michael , Zelles Laszlo , Hartmann Anton , Munch Jean Charles
Published: December 2011

New molecular and biomarker approaches allow now a better understanding of the microbial diversity in soils. Examples are presented to demonstrate the new performance of these approaches and the quality of results. Investigations of the diversity of a bacterial indicator genus as well as studies of the whole microbial community structure are presented. Genotypes of Ochrobactrum were isolated by immunotrapping and characterized by PCR — fingerprinting. On a fallow land no significant changes in the intragenus diversity of this indicator bacterium was observed over a period of one year. In contrast, crop rotation was accompanied by a shift in the dominant genotypes of Ochrobactrum, while the genetic potential was not affected.

Phospholipid fatty acid (PLFA)‐pattern revealed significant shifts in the structure of the whole microbial community in a soil of a hop plantation as compared to a similar soil with crop rotation. The quantity of anaerobic bacteria, represented by the non‐ester linked fatty acids were lower in soil samples derived from crop rotation as compared to a former hop plantation soil, which was contaminated with copper. In contrast, the ester linked fatty acids which are present in a wide range of Gram‐negative and Gram‐positive bacteria, exhibited a reverse relation. Soil samples of the hop plantation contained low amounts of saturated ester linked fatty acids branching on the 10th C atom. This indicates that actinomycetes are present in relative small proportions in the hop plantation soil.
Nitrogen turnover in soil after application of animal manure and slurry as studied by the stable isotope 15N: A review
Authors: Dittert Klaus , Goerges Tjark , Sattelmacher Burkhard
Published: December 2011

In the last decades many aspects of nitrogen turnover have been studied by 15N methods. In this article contemporary 15N tracer as well as natural 15N abundance methods for the study of animal manure turnover are briefly reviewed. The nitrogen dynamics after application of farmyard manure and slurry are elucidated. Here, emphasis was put on results from 15N stable isotope work in the fields of nitrogen immobilization, nitrogenous trace gas emissions, turnover of organic nitrogen fractions, and finally plant uptake. Added nitrogen interactions, which must be considered when interpreting 15N studies, are discussed. Finally promising research fields for the use of stable isotopes are outlined.
Phosphorus availability, root exudates, and microbial activity in the rhizosphere
Authors: Schilling Günther , Gransee Andreas , Deuhel Annette , Ležoviž Grit , Ruppel Silke
Published: December 2011

Field and pot experiments showed that the P demand of wheat is highest in early stages of growth (up to 1.67 μg P per cm2 root surface and day). The needed orthophosphate ions H2PO4− and HPO42‐move from soil to the root by diffusion. This process is controlled by the concentration gradient of the diffusible phosphate and the effective diffusion coefficient according to Pick's first law. Root excretions (rhizodeposition) are able to affect both characteristics. The water soluble portion of rhizodeposition contains more than 50% of up to 8 different sugars, 10–40% carboxylic acids and 10–15 amino acids and amides. The composition varies in dependence on the age of the root parts and on nutrition (Zea mays L., Brassica napus L., Pisum sativum L.). Diffusion experiments using small soil blocks showed that 50–75% of the root exudates were decomposed by respiration within 3 days. The rest was largely chemically converted. Originally present sugars disappeared. Due to the biosynthesis of different organic acids from the individual sugars the mobilisation of Ca3(PO4)2 by Pantoea agglomerans increased when the sugar mixture was derived from the rhizodeposition of P deficient plants with more pentoses instead of glucose and fructose (mainly effect of anions). In the rhizosphere therefore a mixture of rhizodeposition and its conversion products exists which affects the binding of phosphorus in soil and the P transport to the root. This should be considered both for the development of new soil extractants and for modelling the P supply to plants.
The apoplast‐habitat of endophytic dinitrogen‐fixing bacteria and their significance for the nitrogen nutrition of nonleguminous plants
Authors: Hecht‐Buchholz Charlotte
Published: December 2011

Recent attention has been drawn to plant‐growth‐promoting bacteria which colonize not only the rhizosphere and the surface of roots but also the interior of roots and shoots of higher plants. The bacteria are found in the apoplast i.e. intercellular spaces and xylem vessels. These so‐called endophytic bacteria are considered to be more effective in providing the host plant with nitrogen than associative rhizosphere bacteria on the root surface and appear to play an important role in biological nitrogen fixation (BNF) in nonleguminous plants. This is discussed in detail. Bacteria which have been found in the apoplast of nonleguminous plants include Azospirillum spp., Pantoea agglomerans, Acetobacter diazotrophicus, Herbaspirillum spp., Azoarcus spp. and Rhizobium spp. The significance of the apoplastic colonization of these bacteria for the nitrogen nutrition of tropical non‐legumes is discussed.
Potassium fertilization on sandy soils in relation to soil test, crop yield and K‐leaching
Authors: Wulff Frank , Schulz Volker , Jungk Albrecht , Claassen Norbert
Published: December 2011

To study the influence of potassium (K) fertilizer rate on soil test K values, crop yield, and K‐leaching in sandy soils, four long‐term fertilizer experiments (0–60–120–180 kg K ha−1 a−1) were initiated in 1988 in northern Germany on farmers fields. Clay content of the plow layer was about 4%, and organic matter between 2% and 5%. Plant available soil K was estimated with the double lactate (DL) method.

Small grain cereals (rye and barley) did not respond to K fertilization in the 7‐year period even though the soil test value of the K‐0 plots decreased from ca. 90 to ca. 30 mg KDL kg−1 within 3 years. This value remained almost constant thereafter. Crop removal (including straw) of 75 kg K ha−1 a−1 was therefore apparently supplied from nonexchangeable K fractions. Compared to the optimum, no K application reduced the yield of potato by up to 21%, and that of white sugar yield up to 10%. Maximum potato yield was obtained by annually applying 60 kg K ha−1 which resulted in a test value of 60 mg KDL kg−1 soil. Maximum potato yield was also obtained at 40 mg KDL kg−1 soil, however, with a single application of 200 kg K ha−1. Similar results were obtained with sugar beet. This indicates that for maximum yield, even for K demanding crops, it is not necessary to maintain KDL values above 40 mg K kg−1 soil throughout the entire crop rotation.

Soil test values increased roughly proportional to the K fertilizer level. About 120 kg fertilizer K ha−1 a−1, markedly more than crop K removal, was required to maintain the initial KDL of 90 mg kg−1. The K concentration of the soil solution in the top soil measured after harvest was increased exponentially by K fertilizer level and so was K leaching from the plow layer into the rooted subsoil. The leached quantity increased from 22 kg K ha−1 a−1 in the plot without K application to 42.79 and 133 kg Kha−1 a−1 in plots supplied with 60, 120 and 180 kg K ha−1 a−1 respectively. Soil test values around 100 mg KDL kg−1 on sandy soils, as often found in the plow layer of farmers fields, lead to K leaching below the root zone that may exceed the critical K concentration of 12 mg K T−1 for drinking water.
A modified procedure for staining arbuscular mycorrhizal fungi in roots
Authors: Vierheilig Horst , Piché Yves
Published: December 2011

Roots were cleared by boiling in 10% KOH and rinsed several times with tap water. Thereafter roots were boiled in the staining solutions. The staining solutions consisted in different dyes (trypban blue (0.05%), anilin blue (0.05%) and acid fuchsin (0.01%)) which were dissolved in usual household vinegar (5% acetic acid). For best contrast, tryphan and anilin blue stained roots were destained with tap water, whereas acid fuchsin stained roots were destained with vinegar. All fungal structures were stained and clearly visible.
Tandem size exclusion chromatography‐Polyacrylamide gel electrophoresis of humic acids
Authors: Trubetskoj Oleg A. , Trubetskaya Olga E. , Afanasieva Gaida V. , Reznikova Olga I. , Hermosin Bernardo , Saiz‐Jimenez Cesareo
Published: December 2011

Humic acids (HAs) from four soils were fractionated by size exclusion chromatography (SEC) on Sephadex G‐75. Three fractions were obtained in all humic acids, collected and assayed by Polyacrylamide gel electrophoresis (PAGE). The unfractionated HA from each soil was used as reference. Each chromatographic fraction formed one electrophoretic zone corresponding closely to one band of the reference sample with some admixture of the fractions preceding or following. The results indicate that fractionation of HAs by tandem SEC‐PAGE can be successfully used for obtaining fractions of reduced polydispersity and different electrophoretic mobilities. Pyrolysis/methylation‐gas chromatography‐mass spectrometry of the full size preparations of HA and fractions with exactly defined molecular size and electrophoretic mobility showed a different distribution in humic components, mainly lipids, lignin derivatives and N‐containing compounds.
Agricultural suitability of degraded Acrisols and Lixisols of former tea lands in Sri Lanka
Authors: Botschek Johannes , Neu Anni , Skowronek Armin , Jayakody Ananda N.
Published: December 2011

Physical and chemical soil degradation hinder the introduction of mixed cropping systems on former tea lands in the Central Highlands of Sri Lanka. For instance on two typical soil catenas soil properties such as texture, pH, acidity parameters, pedogenic oxides and available plant nutrients indicating fertility are presented. Obviously Al3+ occupies a larger part of the exchange complex and accounts for more soil acidity than H+. Al toxicity is hence a major restricting factor for plant growth in the area. The investigated data also permit an evaluation of soil erodibility and a soil fertility assessment according to the Fertility Capability Classification System (Sanchez et al., 1982). Agricultural measures to reduce soil acidity and cover the lime requirements of the soils are advised. Additional soil conservation measures should diminish soil erosion in order to improve the sustainability of the cropping systems.
Oxidation of methane and dehydrogenase activity in a Mollic Gleysol
Authors: Brzezińska Małgorzata , Kuzyakov Yakov , Włodarczyk Teresa , Stahr Karl , Stȩpniewski Witold
Published: December 2011

It was found that during a 4‐day incubation of a Mollic Gleysol with 352 μl 1−1 methane in the headspace, the rate of methane consumption declined exponentially from an initial value of 9.13 μmol kg−1 hour−1 (about 5% of total CO2 evolved) according to first‐order kinetics. The increase of dehydrogenase activity due to methane amendment did not exceed 15% of the control value and reached the maximum after two days of incubation.
Commentary on the postencephalitic cases of Dr. Kinnier Wilson
Authors: Burn David J.
Published: December 2011

Three cases of postencephalitic parkinsonism that were originally described by Kinnier Wilson are reviewed and some general comments made upon their presentation. A differential diagnosis that might now be appropriate in the 21st Century is given, in the light of recent literature on the topic and so‐called “sporadic” cases. © 2011 Movement Disorder Society
The Wilson films — Huntington's Chorea
Authors: Klein Christine
Published: December 2011

Wilson's Queen Square Case 9 with Huntington's chorea shows a 68‐year‐old man with mild to moderate generalized chorea, impaired fixation, and probable cognitive decline in keeping with a diagnosis of Huntington's disease (HD). An age of onset in the late sixties and a negative family history suggest a relatively small expanded trinucleotide repeat in the HTT gene in the patient and reduced penetrance of an even shorter repeat allele in one of his parents. A highly sensitive and specific gene test has been offered worldwide for diagnostic testing of HD for almost two decades. This test, obviously unavailable at Wilson's times, became the historic frontrunner for guidelines of symptomatic, presymptomatic, and prenatal testing for an adult‐onset neurodegenerative disorder. Regarding treatment of HD, however, we are still awaiting the successful translation of research results into the development of effective cause‐directed, neuropreventive and neurorestaurative therapies. © 2011 Movement Disorder Society
The Wilson films — Parkinson's disease
Authors: Volkmann Jens
Published: December 2011

Short sequences in the Wilson film illustrate clinical aspects of bradykinesia and tremor in Parkinson's disease. What might have been the motivation of Wilson to capture these symptoms, and how would we view them today? © 2011 Movement Disorder Society
UBQLN2/P62 cellular recycling pathways in amyotrophic lateral sclerosis and frontotemporal dementia
Authors: Fecto Faisal , Siddique Teepu
Published: December 2011

Recent findings highlight a pathologic and functional convergence in amyotrophic lateral sclerosis (ALS) and amyotrophic lateral sclerosis with frontotemporal dementia (ALS‐FTD) at the level of protein recycling and disposal. Genes linked to rare cases of familial ALS and ALS‐FTD, like UBQLN2, OPTN, SQSTM1/p62, and VCP, may converge onto a unifying pathogenic pathway and thereby provide novel therapeutic targets common to a spectrum of etiologically diverse forms of ALS and ALS‐FTD. Interactions between these genes need to be further explored to understand their common molecular pathways. Future efforts should be directed toward generation and characterization of in vivo models to dissect the pathogenic mechanisms of ALS and ALS‐FTD and the role of protein degradation pathways, both centrally, at the cell body, and peripherally, at the level of the synapse. Such efforts will rapidly accelerate the discovery of new drugs that regulate accumulation of pathogenic proteins and their downstream consequences in ALS and ALS‐FTD and, possibly, other neurodegenerative diseases as well. Muscle Nerve, 2012
Liquiritigenin Inhibits Serum‐induced HIF‐1α and VEGF Expression via the AKT/mTOR‐p70S6K Signalling Pathway in HeLa Cells
Authors: Xie Si‐Rou , Wang Yu , Liu Chang‐Wei , Luo Kang , Cai Yun‐Qing
Published: December 2011

Liquiritigenin (LQ) is a non‐toxic dietary flavonoid with chemopreventive and anticancer properties. However, the mechanism of its antiangiogenesis remains unclear. Hypoxia‐inducible factor‐1α (HIF‐1α) and its downstream target, vascular endothelial growth factor (VEGF), play a critical role in tumour angiogenesis and represent an attractive chemotherapeutic target. In this study, we investigated the effect of LQ on the molecular mechanism of angiogenesis. We found that LQ inhibited VEGF expression at both mRNA and protein levels. Liquiritigenin did not affect HIF‐1α expression at the mRNA level, but it dramatically inhibited both serum‐ and mimicked hypoxic‐induced HIF‐1α protein accumulation in HeLa cells. Furthermore, we showed that LQ inhibited serum‐induced expression of HIF‐1α by reducing its stability and decreased the synthesis in a dose‐dependent manner. Mechanistically, we demonstrated that LQ inhibited HIF‐1α and VEGF expression involved in blocking the protein kinase B (PKB/Akt) signalling pathway, and the mechanisms correlated with dephosphorylation of the mammalian target of rapamycin (mTOR) and its effector ribosomal protein S6 kinase (p70S6K). In addition, LQ inhibited VEGF‐induced formation of capillary‐like structures in human umbilical vein endothelial cells (HUVEC). Taken together, our study provided valuable insights into the mechanism of antiangiogenic effect of LQ. Copyright © 2011 John Wiley & Sons, Ltd.
The Bayesian information criterion: background, derivation, and applications
Authors: Neath Andrew A. , Cavanaugh Joseph E.
Published: December 2011

The Bayesian information criterion (BIC) is one of the most widely known and pervasively used tools in statistical model selection. Its popularity is derived from its computational simplicity and effective performance in many modeling frameworks, including Bayesian applications where prior distributions may be elusive. The criterion was derived by Schwarz (Ann Stat 1978, 6:461–464) to serve as an asymptotic approximation to a transformation of the Bayesian posterior probability of a candidate model. This article reviews the conceptual and theoretical foundations for BIC, and also discusses its properties and applications. WIREs Comput Stat 2012, 4:199–203. doi: 10.1002/wics.199

This article is categorized under:

Statistical and Graphical Methods of Data Analysis > Bayesian Methods and Theory

Statistical and Graphical Methods of Data Analysis > Information Theoretic Methods

Statistical Learning and Exploratory Methods of the Data Sciences > Modeling Methods
Right hepatectomy with resection of caudate lobe and extrahepatic bile duct for hilar cholangiocarcinoma
Authors: Endo Itaru , Matsuyama Ryusei , Taniguchi Koichi , Sugita Mitsutaka , Takeda Kazuhisa , Tanaka Kuniya , Shimada Hiroshi
Published: December 2011

En‐bloc liver resection with caudate lobectomy (segmentectomy 1) is the standard procedure for hilar cholangiocarcinoma. Although its surgical mortality has been reduced below 5%, it is still a potentially hazardous operation. Complete tumor resection with negative surgical margins and safe reconstruction of bilio‐enteric continuity are two principles of the surgical treatment of hilar cholangiocarcinoma. Surgeons must pay attention to the variation of the hilar structures including portal veins, hepatic arteries, and bile ducts. Three‐dimensional imaging is beneficial not only for understanding anatomical variations but also for preoperative simulations. Since the U‐point can be identified by both preoperative imaging and intraoperative inspection, it can be used as the landmark for the hepatectomy and the dissection point of the hilar plate. The hanging maneuver might be useful for both hepatic parenchymal dissection and bile duct dissection just right of the U‐point. For safe biliary reconstruction, stay sutures in the anterior wall and transanastomotic stents may be helpful.
What Undergraduate Factors Influence Medical Students When Making Their Choice of Post Graduate Career?
Authors: Yap C. , Rosen S. , Sinclair A.M. , Pearce I.
Published: December 2011

Objectives:

To determine what factors final year medical students consider when deciding upon their future post graduate career and to what extent each factor influences their decision.

Methods:

150 final year medical students were asked to complete an anonymous questionnaire relating to factors relating to their future career choice. Students were asked to rate each factor according to the level of importance or influence it exerted when choosing a post graduate career. A simple visual analogue scale from 1 to 10 was utilised with 10 being most influential.

Results:

The most significant factors influencing final year medical students in their career choice were clinical mentors and specialty themed PBL cases with scores of 6.8 and 6.5 out of a maximum of 10. Clinical exposure exerted the weakest influence with a mean score of 2.5.

Conclusion:

Various factors influence the future career choice of final year medical students to a differing extent. In order to promote Urology as a favourable career choice in this cohort, a concerted and coherent effort should be made at national level to engage medical students and promote the specialty.
Prognostic Implication of the Lymphangitic Carcinomatosis Pattern on Perfusion Lung Scan
Authors: Charest Mathieu , Armanious Shadia
Published: December 2011

Purpose

Findings not associated with thromboembolic disease on routine perfusion lung scan may sometimes have particular clinical significance. We wanted to assess the clinical importance and overall survival after the recognition of a lymphangitic carcinomatosis pattern on perfusion lung scan.

Case report

We report a case of lymphangitic carcinomatosis pattern on perfusion lung scan performed in a previously healthy patient who had rapid progressive course and died the next day.

Method

A Medline search of case reports that describes either lymphangitic carcinomatosis or tumour microemboli on perfusion lung scan.

Results

There were a total of 32 patients identified in 21 articles from various countries, including our case. The studied perfusion pattern was reported more often in female patients (81%) was associated with a progressive history of dyspnea (69%) and normal or mild findings on chest radiograph (58%). Of the 29 patients with available outcome data, 79% (23/29) had a progressive course after the lung scan interpretation. In 18 of these 23 cases, the actual interval of survival was given: 67% of these patients (12/18) died within the first month.

Discussion

A lymphangitic carcinomatosis perfusion pattern on scintigraphic imaging is associated with a poor prognosis. Nuclear medicine physicians should be aware of this association and that raising the suspicion for a metastatic process may make a difference in the treatment plan of these patients.
Rapid late Pleistocene/Holocene uplift and coastal evolution of the southern Arabian (Persian) Gulf
Authors: Wood Warren W. , Bailey Richard M. , Hampton Brian A. , Kraemer Thomas F. , Lu Zhong , Clark David W. , James Rhodri H.R. , Al Ramadan Khalid
Published: December 2011

The coastline along the southern Arabian Gulf between Al Jubail, Kingdom of Saudi Arabia, and Dubai, UAE, appears to have risen at least 125 m in the last 18,000 years. Dating and topographic surveying of paleo-dunes (43–53 ka), paleo-marine terraces (17–30 ka), and paleo-marine shorelines (3.3–5.5 ka) document a rapid, > 1 mm/a subsidence, followed by a 6 mm/a uplift that is decreasing with time. The mechanism causing this movement remains elusive but may be related to the translation of the coastal area through the backbasin to forebulge hinge line movement of the Arabian plate or, alternatively, by movement of the underlying Infracambrian-age Hormuz salt in response to sea-level changes associated with continental glaciation. Independent of the mechanism, rapid and episodic uplift may impact the design of engineering projects such as nuclear power plants, airports, and artificial islands as well as the interpretation of sedimentation and archeology of the area.
Jean-Jacques Rousseau and the 'Well-Ordered Society'
Authors: Viroli Maurizio
Published: December 2011

This book studies a central but hitherto neglected aspect of Rousseau's political thought: the concept of social order and its implications for the ideal society which he envisages. The antithesis between order and disorder is a fundamental theme in Rousseau's work, and the author takes it as the basis for this study. In contrast with a widely held interpretation of Rousseau's philosophy, Professor Viroli argues that natural and political order are by no means the same for Rousseau. He explores the differences and interrelations between the different types of order which Rousseau describes, and shows how the philosopher constructed his final doctrine of the just society, which can be based only on every citizen's voluntary and knowing acceptance of the social contract and on the promotion of virtue above ambition. The author also shows the extent of Rousseau's debt to the republican tradition, and above all to Machiavelli, and revises the image of Rousseau as a disciple of the natural-law school.
The Genus Rhipicephalus (Acari, Ixodidae)
Authors: Walker Jane B. , Keirans James E. , Horak Ivan G.
Published: December 2011

Ticks in the genus Rhipicephalus include many important vectors of animal and human pathogens, but many species are notoriously difficult to identify, particularly as immature stages. This reference volume provides identification keys for adult ticks from the Afrotropical regions and elsewhere. For the nymphs and larvae, unique plates have been compiled in which line drawings of the capitula of similar species are grouped together to facilitate identification. Brief well-illustrated descriptions of the known stages of every species are given, plus information on their hosts, distribution, and disease relationships. Tables providing data on host/parasite relationships and disease transmission are also included, making this the definitive reference source on this group for all those interested in acarology, veterinary or medical parasitology and entomology for many years to come.
An Investigation of the Laws of Thought
Authors: Boole George
Published: December 2011

Self-taught mathematician and father of Boolean algebra, George Boole (1815–1864) published An Investigation of the Laws of Thought in 1854. In this highly original investigation of the fundamental laws of human reasoning, a sequel to ideas he had explored in earlier writings, Boole uses the symbolic language of mathematics to establish a method to examine the nature of the human mind using logic and the theory of probabilities. Boole considers language not just as a mode of expression, but as a system one can use to understand the human mind. In the first 12 chapters, he sets down the rules necessary to represent logic in this unique way. Then he analyses a variety of arguments and propositions of various writers from Aristotle to Spinoza. One of history's most insightful mathematicians, Boole is compelling reading for today's student of intellectual history and the science of the mind.