bluuebunny/crossref_metadata_2025 huggingface dataset:
Interaction of Humic Substances and Polycyclic Aromatic Hydrocarbons (PAHs) during the Biodegradation of PAHs
Authors: Seibel F. , Heidenreich S. , Frimmel F. H.
Published: February 2007

The influence of humic substances (HS) on the biodegradation of naphthalene, phenanthrene, and pyrene was studied. As a source of HS, water samples of a bog lake (Hohlohsee) were used. PAH degradation experiments, both in the presence and absence of HS were carried out. All investigated PAHs were degradable by the used bacterial mixed culture. A correlation between the number of aromatic rings of the PAHs and the influence of HS on biodegradation has been shown. Adding of HS led to a decrease in degradation rate in the case of naphthalene. By way of contrast, the presence of HS gave rise to an increase of degradation rate in the case of phenanthrene. The degradation processes of pyrene revealed a marked alteration in the presence of HS which could be deduced from the biochemical oxygen demand (t(1/2BODmax) values). With regard to the total turnover of the PAHs, there was no noticeable difference between degradation experiments with and without HS. Analyses of the HS after degradation experiments using liquid chromatography coupled with DOC detection (LC/OCD) verify that there was no formation of stable associations between HS and PAHs or their metabolites. The determination of the toxicity of the degradation media as luminescence inhibition against Vibrio fischeri (Photobacterium phosphoreum) showed no detoxification as a result of the presence of HS.
Nanofiltration in Combination with Limestone Filtration for Treating a Soft Spring Water Containing High Amounts of Humic Substances
Authors: Lipp P. , Baldauf G.
Published: February 2007

The paper presented here describes experiments with a nanofiltration pilot plant treating spring water which contains high amounts of humic substances. With this process, water components such as humic substances, iron, manganese, and aluminum may be very well removed. However, the low pH value of the NF filtrate does not conform with the German standards. This is why the pH value will be increased in a second treatment step by limestone filtration. Prior to limestone filtration, CO2 dosage is required in order to make sure that the pH value stays below the upper limit of the German standards of 9.5. With this treatment, a drinking water results which meets the German standards and has good chemical properties with respect to corrosion.

The operation of the nanofiltration pilot plant for the treatment of the very soft spring water did not require the continuous addition of chemicals in order to prevent scaling. Although the spring water entered the NF without chemical pretreatment, there was no decrease in filtrate capacity observed over a period of six months. This is in contrast to other investigations involving colour reduction from very hard surface waters. When treating very hard waters by nanofiltration, the addition of complexing agents or acid is required in order to prevent scaling of the membranes. Such intricate pretreatment procedures cause doubt of the application of nanofiltration for the treatment of hard waters in large plants. However, in the case presented here, the application of NF in combination with the hardening step is quite simple, so that the full‐scale plant may be operated mainly automatically and will require only little maintenance.
Nitrous Oxide Emissions in Sewer Systems
Authors: Clemens J. , Haas B.
Published: February 2007

Nitrous oxide emissions from urban wastewater were measured in a combined sewer in Bayreuth, Germany. The closed‐chamber method was used to evaluate N2O emissions. Nitrous oxide was analysed by gas chromatography with electron capture detector. Longitudinal and daily variations of N2O fluxes were determined. N2O emissions ranged from 0.11…3.8 mg m−2 h−1 depending on the level of wastewater in the sewer. Data indicate that N2O is mainly formed in the biofilm by nitrification and/or denitrification. In laboratory experiments, samples with wastewater and wastewater/biofilm mixture were incubated with and without NaCl. After two hours of incubation, N2O release was in a range of 42…429 ng N2O per millilitre wastewater or wastewater/biofilm. Incubated samples without NaCl addition showed no significant difference between wastewater and wastewater/biofilm mixture. If salt (NaCl) was added before incubation, samples with wastewater/biofilm mixture emitted 4.8 times more N2O than wastewater samples. It is assumed that high concentrations of NaCl inhibit further microbial reduction of N2O to N2.

Based on the field data, a first estimate for N2O emission from sewers is 3.5 g N2O per year and person.
Geochemische und 13C/12C‐isotopenchemische Untersuchung zur Herkunft der Kohlensäure in mineralhaltigen Wässern Nordhessens (Deutschland)
Authors: Dietzel M. , Schwecke H. , Hirschfeld A. , Röhring M. , Böttcher M. E.
Published: February 2007

Die Untersuchung zeigt, daß die Carbonatgehalte der Wässer aus drei Quellen erhalten werden: 1. biogenes CO2 aus dem Boden, 2. vulkanogenes CO2 aus dem Zechstein‐Salz und 3. Carbonat aus Kalk und Dolomit. Das vulkanogene CO2‐Gas entstammt ursprünglich den miozänen basaltischen Schmelzen, die bei ihrem Aufstieg die Zechstein‐Salze durchbrachen. Das CO2 wurde in Intra‐ und Intergranularen des Salzgesteins gespeichert und wird bei Zutritt von zirkulierenden meteorischen Wässern freigesetzt. Bei hoher Basalthäufigkeit mit hieraus resultierenden hohen Gehalten an CO2‐Gas im Salzgestein reichen schon relativ geringe Mengen von aufgelöstem Salz aus, um große Mengen an „Salz‐CO2”︁ für die Auflösung von Kalk und Dolomit zur Verfügung zu stellen.

Aus der Zusammensetzung von carbonatreichen Wässern ergab sich ein δ13C‐Wert für das Salz‐CO2 von –1‰ (PDB). Während in diesen Wässern der Anteil von Salz‐CO2 gegenüber biogenem CO2 dominiert, nimmt in den carbonatarmen Wässern der Anteil von Salz‐CO2 am Carbonatgehalt bis auf etwa 20% ab.
Untersuchung der Sorptionseigenschaften des Kationenaustauschers KB‐2M mit Makronetzstruktur zur Abtrennung von Zinkionen aus Ab‐ und Spülwässern
Authors: Kononowa O. N. , Cholmogorow A. G. , Paschkow G. L. , Wdowina G. P.
Published: February 2007

Obwohl Ionenaustauschprozesse im Rahmen der Abwasserreinigung ziemlich gut untersucht worden sind, fehlen noch Kenntnisse über Ionenaustauscher mit Makronetzstruktur. In der vorliegenden Arbeit werden Ergebnisse der Untersuchung von Sorptionseigenschaften des Kationenaustauschers KB‐2M mit Makronetzstruktur im Vergleich mit Harzen von poröser und nichtporöser Struktur zusammengefaßt. Die von uns hergestellten Carboxylharze wurden für die Abtrennung der Zn2+‐Ionen aus Ab‐ und Spülwässern unter statischen und dynamischen Bedingungen angewandt.

Zur Aufklärung der Harzstruktur vor und nach der Zinksorption wurden verschiedene physikalische Methoden herangezogen, wie Quecksilberporosimetrie, IR‐Spektroskopie, Elektronenmikroskopie und Röntgenstrukturanalyse. Der Zinkgehalt in Lösungen wurde mittels AAS‐Methode bestimmt. Aus den IR‐spektroskopischen und kinetischen Angaben gelang es, den Sorptionsmechanismus der Zinkionen aufzuklären. Die erhaltenen Ergebnisse gestatten zu sagen, daß der Kationenaustauscher KB‐2M mit Makronetzstruktur am besten für die Zinksorption aus Ab‐ und Spülwässern geeignet erscheint.
Mobilisierbarkeit von hydrophoben organischen Schadstoffen in belasteten Böden und Abfällen. Teil I: Mobilisierbarkeit von PCB, PAK und n‐Alkanen durch Lösungsvermittler
Authors: Pestke F. M. , Bergmann C. , Rentrop B. , Maaßen H. , Hirner A. V.
Published: February 2007

Zur Einbeziehung möglicher Effekte von organischer Substanz im Feststoff und im Eluat hinsichtlich der potentiellen Mobilisierung von hydrophoben organischen Schadstoffen aus Böden und Abfällen wird die Schadstoffmobilisierung durch tensidische Lösungen einerseits und jene durch naturnahe Lösungsvermittler andererseits verglichen. Während unter den Bedingungen des Elutionsverfahrens nach DIN 38414 Teil 4 gegenüber Eluenten mit organischen Naturstoffen erhebliche und in ihrem Ausmaß unterschiedliche Minderbefunde ermittelt werden, können deren mobilisierende Eigenschaften durch die eingesetzte tensidische Lösung gut simuliert werden.
Ein kompetitiver Immunoassay zur Bestimmung des Herbizids Fluazifop in Trink‐ und Grundwasser
Authors: Poppe F. , Rubach K.
Published: February 2007

Für den Nachweis des Herbizids Fluazifop [(RS)‐2‐[4‐(5‐Trifluormethyl‐2‐pyridyloxy)‐phenoxy]propionsäure] in Trink‐ und Grundwasser wurde vor dem Hintergrund des aktuellen Grenzwertes der Trinkwasserverordnung ein kompetitiver Festphasen‐Enzymimmunoassay mit polyklonalen Antikörpern vom Kaninchen entwickelt. Das Trägerprotein für die Immunisierungen war Rinderserumalbumin; als Markerenzym wurde Meerrettich‐Peroxidase mit dem Substrat 3,3′, 5,5′‐Tetramethylbenzidin verwendet. Eine hohe Konzentration hochaffiner Antikörper im Serum, die Optimierung der Testbedingungen (Antikörper‐ und Enzymtracerkonzentration, Inkubationszeit etc.) und sehr geringe Kreuzreaktivitäten mit strukturähnlichen Substanzen führten zu einem hochempfindlichen und selektiven ELISA mit einer Nachweisgrenze unter 0.1 μg/L für Fluazifop als freie Säure. Für die Eignungsüberprüfung des Assays als Screening‐Test wurden aus hundert Trinkwasserproben drei laborintern dotierte Proben bezüglich des Gehaltes an Fluazifop (freie Säure) als positiv erkannt. Zwei weitere Proben erwiesen sich bei der gaschromatographisch‐massenspektrometrischen Konfirmation als falsch positv. Falsch negative Resultate traten nicht auf. Die Konzentration lag im Grenzwertbereich von 0.1 μg/L.
Fault‐tolerant control of nonlinear process systems subject to sensor faults
Authors: Mhaskar Prashant , Gani Adiwinata , McFall Charles , Christofides Panagiotis D. , Davis James F.
Published: February 2007

The problem of control of nonlinear process systems subject to input constraints and sensor faults (complete failure or intermittent unavailability of measurements) is considered. A fault‐tolerant controller is designed that utilizes reconfiguration (switching to an alternate control configuration) in a way that accounts for the process nonlinearity, the presence of constraints and the occurrence of sensor faults. To clearly illustrate the importance of accounting for the presence of input constraints, first the problem of sensor faults that necessitate sensor recovery to maintain closed‐loop stability is considered. We address the problem of determining, based on stability region characterizations for the candidate control configurations, which control configuration should be activated (reactivating the primary control configuration may not preserve stability) after the sensor is rectified. We then consider the problem of asynchronous measurements, that is of intermittent unavailability of measurements. To address this problem, the stability region (that is, the set of initial conditions starting from where closed‐loop stabilization under continuous availability of measurements is guaranteed), as well as the maximum allowable data loss rate which preserves closed‐loop stability for the primary and the candidate backup configurations are computed. This characterization is utilized in identifying the occurrence of a destabilizing sensor fault, and in activating a suitable backup configuration that preserves closed‐loop stability. The proposed method is illustrated using a chemical process example and demonstrated via application to a polyethylene reactor. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Rejecting highly cited papers: The views of scientists who encounter resistance to their discoveries from other scientists
Authors: Campanario Juan Miguel , Acedo Erika
Published: February 2007

We studied the views of scientists who experience resistance to their new ideas by surveying a sample of 815 scientists who are authors of highly cited articles. The 132 responses (16.2%) received indicated that only 47 scientists (35.6%) had no problems with referees, editors, or other scientists. The most common causes of difficulty were rejection of the manuscript, and scepticism, ignorance, and incomprehension. The most common arguments given by referees against papers were that the findings were an insufficient advance to warrant publication, lacked practical impact, were based on a wrong hypothesis, or were based on a wrong concept. The strategies authors used to overcome resistance included obtaining help from someone to publish problematic papers, making changes in the text, and simple persistence. Despite difficulties, however, some respondents acknowledged the positive effect of peer review.
Bestimmung des Einflusses von Karststrukturen auf die dauerhafte Stand‐ und Betriebssicherheit von Verkehrstunneln durch 3D‐Finite‐Element‐Modellierung
Authors: Pöttler Rudolf , Spiegl Andreas
Published: February 2007

Zahlreiche Tunnelbauten werden in verkarstetem Gebirge geplant und ausgeführt. Eine Beherrschung der Karst‐ und Erdfallproblematik bedeutet, daß für das Bauwerk eine dauerhafte Betriebssicherheit bei möglichst ständiger Verfügbarkeit gegeben ist.

Basis für die Behandlung der Problematik bilden umfangreiche Baugrunderkundungen. auf deren Dokumentation sich die geologisch/hydrogeologische Risikobeurteilung stützt. Daraus ergibt sich der Umfang der erforderlichen zusätzlichen Baugrunduntersuchungen für eine weitere Erkundungsphase. Aufbauend auf diesen Grundlagen werden Gebirgsmodelle und Gefährdungsbilder entwickelt und in weiterer Folge der Einfluß von Karststrukturen auf das Tunnelbauwerk untersucht.

Dieser Beitrag befaßt sich schwerpunktmäßig mit den numerischen Untersuchungen, die zum Nachweis der Stand‐ und Betriebssicherheit des Tunnel Irlahüll der Neubaustrecke Nürnberg–Ingolstadt der Deutschen Bahn vorgenommen wurden. Die Ausführungen veranschaulichen die Nützlichkeit und Sinnhaftigkeit aufwendiger numerischer Berechnungsverfahren, um das komplexe Trag‐ und Verformungsverhalten eines Tunnels im Karstgebirge realitätsnah zu erfassen und damit wirtschaftlich optimierte und gleichzeitig nachhaltig standsichere Lösungen zu erarbeiten.
DNA adducts in human placenta exposed to ambient environment and passive cigarette smoke during pregnancy
Authors: Sanyal Mrinal K. , Mercan Derya , Belanger Kathleen , Santella Regina M.
Published: February 2007

BACKGROUND:

The risk of human diseases and abnormal development under the relatively reduced toxic environmental exposure conditions of passive cigarette smoke and urban pollution is emerging as significant. To assess the genotoxic potential of such exposure, we analyzed the DNA adducts of polynuclear aromatic hydrocarbons (PAH), a proven marker of genotoxicity, in human placental DNA samples of pregnancies monitored for passive cigarette smoke exposure.

METHODS:

Maternal exposure to active and passive cigarette smoke was evaluated by verbal disclosure and urinary nicotine and cotinine measurements. PAH‐DNA adducts were assayed by ELISA using a polyclonal antibody against benzo[α]pyrene‐diol‐epoxide‐DNA in placental DNA. Birth weights of infants were recorded in these monitored pregnancies.

RESULTS:

Urinary nicotine and cotinine values were reduced in the passive smoke–exposed group compared to smokers and similar to those in the nonsmoker ambient exposure group. PAH‐DNA and nicotine/cotinine values were not correlated with birth weight of the infant. PAH‐DNA adducts were present in ∼25% of samples exposed to passive cigarette smoke and ambient environment.

CONCLUSIONS:

The study has revealed that a subpopulation of humans is predisposed to accumulating PAH adducts independent of high levels of PAH sources (e.g., maternal cigarette smoke exposure). Because DNA adducts promote genomic changes, it is likely that this subpopulation is susceptible to diverse changes in the genome that may influence human development. Birth Defects Research (Part A) 2007. © 2007 Wiley‐Liss, Inc.
Solution structures and biological functions of the antimicrobial peptide, arenicin‐1, and its linear derivative
Authors: Lee Ju‐Un , Kang Dong‐Il , Zhu Wan Long , Shin Song Yub , Hahm Kyung‐Soo , Kim Yangmee
Published: February 2007

Arenicin‐1 (AR‐1) is a novel antimicrobial peptide that was isolated from coelomocytes of the marine polychaeta lugworm Arenicola marina and shown to contain a single disulfide bond between Cys3 and Cys20, forming an 18‐residue ring [Ovchinnikova, T. V. et al., FEBS Lett 2004, 577, 209–214]. To determine the role of this disulfide bond, we synthesized AR‐1 (RWCVYAYVRVRGVLVRYRRCW) and its linear derivative, arenicin‐1‐S (AR‐1‐S: RWSVYAYVRVRGVLVRYRRSW). Activity assays revealed that AR‐1‐S is somewhat less active against bacterial cells than AR‐1. Both peptides were very hydrophobic, and displayed cytotoxicity against human red blood cells. Analysis of the tertiary structures of AR‐1 and AR‐1‐S by NMR spectroscopy disclosed that AR‐1 has two‐stranded antiparallel β‐sheet structures with amphipathicity, while AR‐1‐S displays a random coil structure in DMSO. Our biological data for AR‐1 and AR‐1‐S indicate that the hydrophobic‐hydrophilic balance, disulfide bridge, and the amphipathic β‐sheet structure of the peptides play important roles in their biological activities. Elucidation of the structure of AR‐1 and its derivative should facilitate the design of novel non‐cytotoxic peptide antibiotics with potent antibacterial activities. © 2007 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 88: 208–216, 2007.

This article was originally published online as an accepted preprint. The ‘Published Online’ date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Acrolein: Doppelflinte im Zigarettenrauch
Authors: Hille‐Rehfeld Annette
Published: February 2007

Nach Angaben der Weltgesundheitsorganisation sterben jährlich mehr als zwei Millionen Menschen an den Folgen des Rauchens. Zigarettenrauch enthält zahlreiche mutagene Substanzen, die mit der Entstehung von Lungenkrebs in Zusammenhang gebracht werden. Acrolein, ein abundantes, stark toxisches Verbrennungsprodukt aus Zigarettenrauch, fördert die Entstehung von Punktmutationen im Genom und hemmt davon unabhängig wichtige DNA‐Reparaturenzyme.
Alois Alzheimer beschreibt eine rätselhafte Krankheit
Authors: Dahm Ralf
Published: February 2007

Im Jahr 1907 veröffentlicht ein junger Arzt einen kurzen Artikel, in dem er die psychiatrischen Symptome und veränderte Histologie des Gehirns seiner verstorbenen Patientin Auguste D. beschreibt. Dieser Artikel ist die erste Veröffentlichung über die Krankheit, die heute seinen Namen trägt: Alzheimersche Krankheit.
Scharfe Gemeinsamkeiten
Authors: Wendler Silke
Published: February 2007

Wie amerikanische Forscher jetzt entdeckt haben, wehrt sich kurioserweise die in West‐Indien beheimatete Vogelspinne Psalmopoeus cambridgei mit der gleichen Strategie gegen Fressfeinde wie die Chilipflanze.
Are release recommendations for NGRI acquittees informed by relevant data?
Authors: Manguno‐Mire Gina M. , Thompson John W. , Bertman‐Pate Lisa J. , Burnett Darla R. , Thompson Hilary W.
Published: February 2007

We conducted a retrospective review of factors involved in clinical recommendations for release of patients adjudicated not guilty by reason of insanity (NGRI). Medical records from 91 patients in a maximum security forensic hospital who participated in a formal hearing process to determine suitability for release were reviewed. The purpose of the study was twofold: (1) to examine the process involved in day to day clinical decision‐making regarding release from a maximum security forensic hospital and (2) to determine what factors in a patient's clinical and legal history were related to recommendation decisions. Multivariate statistical methods revealed that among the clinical, demographic, and legal information available to clinicians at the time a formal release recommendation was made two factors emerged that were significantly related to release recommendations: PCL‐R score and the age at which the patient committed his first criminal offense. Patients with high levels of psychopathy and those who engaged in criminal behavior at a younger age were less likely to be recommended for release from a maximum security forensic hospital. Copyright © 2007 John Wiley & Sons, Ltd.
Geld stinkt nicht
Authors: Pingel Keuth Andreas
Published: February 2007

Pecunia Non Olet – “Geld stinkt nicht”, sagte der Legende nach Kaiser Vespasian zu seinem Sohn Titus und hielt ihm Geld aus den Einnahmen seiner Urinsteuer unter die Nase, als dieser ihm vorwarf, dass diese Steuer anrüchig sei. Aber wir haben alle schon den muffig metallischen Geruch wahrgenommen, wenn wir mit feuchten oder verschwitzten Händen Eisen oder Rotgeld angefasst haben. Was riecht da nun?
Resveratrol, die Wunderdroge des Rotweins...
Authors: Jaenicke Lothar
Published: February 2007

Seit die Anbauflächen für Rotweintrauben und der transkontinentale Handel mit deren Gärungsprodukt globalisiert wurden, taucht diese Vorzugsgabe Alter Knaben in der Pharmalore immer wieder als Wundermittel ihrer Klientel auf: zum Verjüngen, Herzstärken und nun auch Schlankhalten, oder mindestens Genießen‐ohne‐Reue.
Patients with differentiated thyroid cancer have a venous gradient in thyroglobulin levels
Authors: Kebebew Electron , Reiff Emily
Published: February 2007

BACKGROUND.

Although serum thyroglobulin (Tg) is an excellent marker for detecting recurrent or persistent differentiated thyroid cancer (DTC), it is unreliable in patients who have positive anti‐Tg antibodies. Furthermore, a growing number of patients with DTC have elevated Tg levels but no detectable disease on radioiodine scanning or other imaging studies. The objective of this study was to determine whether a gradient in Tg protein level exists in patients with DTC.

METHODS.

Fifteen patients who underwent thyroidectomy and/or lymph node dissection for primary DTC (n = 10 patients) and recurrent or persistent DTC (n = 5 patients). A venipuncture was performed simultaneously from the internal jugular vein adjacent to the tumor and the ipsilateral antecubital vein. Venous Tg protein levels were measured by using a chemiluminescence assay.

RESULTS.

The average internal jugular‐to‐antecubital vein Tg protein ratio was 3.4:1.0 (median Tg ratio, 2.9:1; range, 0.8–62.2). Four patients had positive anti‐Tg antibodies but still had a Tg gradient. Tg levels were significantly higher in the adjacent internal jugular vein than in the antecubital vein (P = .0019). The Tg ratio between the internal jugular and antecubital veins was significantly higher in patients with recurrent or persistent DTC than in patients with primary tumors (P = .0196).

CONCLUSIONS.

To the authors' knowledge, this is the first study to document a venous gradient in Tg protein levels in patients with DTC. The findings suggested that venous sampling for Tg may be used to localize DTC in some patients who have high or increasing serum Tg levels but negative radioiodine scans or imaging studies. Cancer 2007 © 2007 American Cancer Society.
Photophysics of Eumelanin: Ab Initio Studies on the Electronic Spectroscopy and Photochemistry of 5,6‐Dihydroxyindole
Authors: Sobolewski Andrzej L. , Domcke Wolfgang
Published: February 2007

Excited‐state reaction paths and energy profiles of 5,6‐dihydroxyindole (DHI), one of the elementary building blocks of eumelanin, have been determined with the approximated singles‐and‐doubles coupled‐cluster (CC2) method. 6‐Hydroxy‐4‐dihydro‐indol‐5‐one (HHI) is identified as a photochromic species, which is formed via nonadiabatic hydrogen migration from the dangling OH group of DHI to the neighboring carbon atom of the six‐membered ring. It is shown that HHI is a typical excited‐state hydrogen‐transfer (ESIHT) system. HHI absorbs strongly in the visible range of the spectrum. A barrierless hydrogen transfer in the 1ππ* excited state, followed by barrierless torsion of the hydroxyl group, lead to a low‐lying S1–S0 conical intersection and thus to ultrafast internal conversion. This very efficient mechanism of excited‐state deactivation provides HHI with a high degree of intrinsic photostability. It is suggested that the metastable photochemical product HHI plays an essential role for the photoprotective biological function of eumelanin.
An image analysis approach for automatic malignancy determination of prostate pathological images
Authors: Farjam Reza , Soltanian‐Zadeh Hamid , Jafari‐Khouzani Kourosh , Zoroofi Reza A.
Published: February 2007

Background:

Determining malignancy of prostate pathological samples is important for treatment planning of prostate cancer. Traditionally, this is performed by expert pathologists who evaluate the structure of prostate glands in the biopsy samples. However, this is a subjective task due to inter‐ and intra‐observer differences among pathologists. Also, it is time‐consuming and difficult to some extent. Therefore, automatic determination of malignancy of prostate pathological samples is of interest.

Methods:

A texture‐based technique is first used to segment the prostate glands in the image. Features related to size and shape of these glands are then extracted and combined to generate an index, which is proportional to malignancy of cancer. A linear classifier is employed to classify the specimens into benign (low potential for malignancy) and malignant.

Results:

The leave‐one‐out technique is employed to evaluate the method using two datasets. The first has 91 images with similar magnifications and illuminations while the second has 199 images with different magnifications and illuminations. In the experiments, accuracies of about 98 and 95% have been achieved for these two datasets, respectively.

Conclusions:

An image analysis approach is employed to evaluate prostate pathological images. Experimental results show that the proposed method can successfully classify the prostate biopsy samples into benign and malignant. They also show that the proposed method is robust to variations in magnification and illumination. © 2007 Clinical Cytometry Society
A one‐dimensional model for simulating armouring and erosion on hillslopes: 2. Long term erosion and armouring predictions for two contrasting mine spoils
Authors: Sharmeen Saniya , Willgoose Garry R.
Published: February 2007

This paper investigates the dynamics of soil armouring as a result of fluvial erosion for a non‐cohesive sandy gravel spoil from the Ranger Mine, Australia, and a cohesive silt loam spoil from the Northparkes Mine, Australia, using a model for hillslope soil armouring. These long term predictions concentrate on the temporal and spatial changes of the spoil grading and erosion over 100–200 years for the flat cap regions (1–2%) and steep batter edges (10–30%) typically encountered on waste rock dumps. The existence of a significant rock fragment fraction in the Ranger spoil means that it armours readily, while Northparkes does not. For Ranger the waste rock showed reductions in (1) cumulative erosion of up to 81% from that obtained by extrapolating the initial erosion rate out 100 years and (2) the erosion/year by more than 10‐fold. For Northparkes reductions were less marked, with the maximum reduction in erosion/year being 37% after 200 years. For Ranger the reductions were greatest and fastest for intermediate gradient hillslopes. For the steepest hillslopes the armouring decreased because the flow shear stresses were large enough to mobilize all material in the armour layer. Model uncertainty was assessed with probabilistic confidence limits demonstrating that these erodibility reductions were statistically significant. A commonly used hillslope erosion model (sediment flux = β1 discharge m1 slope n1) was fitted to these predictions. The erodibility, β1, and m1 decreased with time, which was consistent with our physical intuition about armouring. At Ranger the parameter m1 asymptoted to 1·5–1·6 while at Northparkes it asymptoted to 1·2–1·3. At Ranger transient spatial trends in armouring led to a short term (50–200 years in the future) reduction in n1, to below zero under certain circumstances, recovering to an asymptote of about 0·5–1. At Northparkes n1 asymptoted to about 0·6, with no negative transients predicted. The m1 and n1 parameters predicted for Ranger were shown to be consistent with field data from a 10‐year‐old armoured hillslope and consistent with published relationships between erodibility and rock content for natural hillslopes. Copyright © 2007 John Wiley & Sons, Ltd.
‘Total’ fabric of some till landforms
Authors: Derbyshire Edward , McGown Alan , Radwan Amr
Published: February 2007

The distinction between clast‐dominant, matrix‐dominant and well‐graded tills is important in view of the influence of texture on the definition and function of till fines. Till fabric includes a wide range of features of both primary and secondary origin including folds, thrusts, fissures (the macrofabric), disposition of clasts (the mesofabric) and organization of the matrix (the microfabric). The results of fabric analysis of pebble, granule, sand, silt and clay in small depositional landforms beneath currently‐active glaciers are described. Deformation fabrics are distinguished in freshly deposited end moraines and flutes. The sand‐size material in deformed till may or may not behave in the same way as larger clasts, depending on the degree to which the till is matrix‐dominant. While clasts in saturated subglacial till tend to align themselves sub‐parallel to the depositional surface, the matrix usually retains abundant pore spaces. With slow, unloaded drainage, clast fabrics appear to be little modified. Such material is potentially unstable and any subsequent increase in overburden and hydraulic pressures may cause slope collapse and flowtill development. It is concluded that examination of a wide range of fabric parameters provides a means of distinguishing tills of diverse origins and of assessing their potential instability.
Stability of minerals in surface weathering reactions: A general thermochemical approach
Authors: Curtis C. D.
Published: February 2007

A list of formational free energy data is provided for a range of common rock forming minerals. Free energy changes accompanying their decomposition to realistic stable products are calculated and shown to be in agreement with persistence observations. Weathering mechanisms and environmental controls are discussed.
The morphology and hydrology of some Jamaican karst depressions
Authors: Day Michael
Published: February 2007

An area of shallow karst depressions in St. Ann parish, Jamaica is examined. Shallow, ‘temperate’ forms such as these are common in tropical karst areas.

Depressions are analyzed morphometrically and a considerable degree of structural control appears to be exhibited. Some morphometric parameters, in particular the depth/diameter ratio, which have been used to postulate depression origin, are examined.

Depression hydrology is investigated. Depressions appear to exhibit characteristics of small drainage basins. The occurrence of sporadic flood events is suggested as an important element in the development of surface channel networks. The integration of the depressions into the regional drainage system is investigated by water tracing of ‘underground flow sections’.

Chemical analysis of waters in various parts of the drainage system reveals variations which point to the importance of solutional activity at the soil‐bedrock interface. The influence of a soil cover in promoting solutional activity is indicated.
Soils and geomorphology of the chalk in south‐east England
Authors: Catt J. A. , Hodgson J. M.
Published: February 2007

Soil mapping and soil profile studies on the Chalk of south‐east England outline the distribution and origin of superficial deposits more clearly than hitherto, and do not support the widely accepted history of landscape development proposed by Wooldridge and Linton (1955). Deposits formed by weathering and periglacial disturbance of a thin cover of basal Tertiary deposits occur on all parts of the dip‐slope interfluves, suggesting that the exhumed sub‐Tertiary surface, somewhat lowered by dissolution of the Chalk, is much more extensive than supposed by Wooldridge and Linton. The evidence for high Plio‐Pleistocene sea levels is reviewed, with particular reference to their limited effect on soils and superficial deposits and on the morphology of the dip‐slope. Alternative explanations for the so‐called Calabrian marine platform and cliff are considered. Emphasis is placed on periglacial processes in the later Pleistocene denudation of the Chalk, and on the protective role played by the cover of disturbed basal Tertiary sediment.
Applications of the random model of drainage basin composition
Authors: Smart J. S. , Werner C.
Published: February 2007

The random model of drainage basin composition is founded on the assumptions that (a) natural channels are topologically random in the absence of geological controls and (b) for channel networks developed in similar environments, the exterior and interior link lengths are independent random variables with a common distribution for each type. The effectiveness of this model in estimating the values of geomorphic variables and in explaining and predicting geomorphic relationships is illustrated by several examples. The data required for these examples were obtained from map studies of 30 channel networks, comprising a total of about 8700 links, in eastern Kentucky. A common factor in the success of all three applications of the model is the way in which the planimetric features of drainage basins are determined by their underlying topologic structure.
Runoff generative process and runoff yield from arid talus mantled slopes
Authors: Yair A. , Lavee H.
Published: February 2007

Previous works dealing with the influence of a stone cover on runoff yield showed that runoff, attributed to the sealing effect of the topsoil by raindrops impact, was negatively related to the per cent of stone cover and stone size. These works were conducted on gentle slopes (3–11·5 degree) with a per cent of stone cover generally lower than 50 per cent, and composed of gravels. The present study deals with the runoff yield of steep talus slopes (26–36 degree) whose per cent of stone cover is very high (90–100 per cent), composed of cobbles and boulders. Three stimulated rainstorms were performed at various rainfall. intensities and durations on each one of six plots representative of the North eastern sector of Sinai. Although the contiguous stony cover prevented surface sealing by raindrops impact, runoff developed quite quickly on most slopes, and reached at peak discharge, after approximately ten minutes, up to 56 per cent of the rainfall. Differences between plots, in time lag, peak discharge and other hydrological variables, could be attributed mainly to the properties of the upper stony layer, with stone size as the most influential factor. Contrary to previous works, a positive relationship, was obtained between stone size to runoff yield. The result is explained by the process of water concentration. Each cobble and boulder behaves, on a smaller scale, like a bare rocky surface and yields per unit area water amounts beyond the infiltration rate of the limited uncovered areas. For a given stony cover the effect of water concentration is quicker with the big blocks than with gravels. A series of graphs trying to relate theoretically the relative importance of sealing and water concentration processes in runoff generation, at various conditions of stone cover and stone size, is proposed. The graphs enable to reconcile the results of the present study with those of previous works.
Lichens and the determination of river channel capacity
Authors: Gregory Ken J.
Published: February 2007

The identification of channel capacity associated with a particular frequency of peak discharges is necessary for discharge estimation for planning purposes at ungauged sites. Although lichen limits have been suggested to be useful for this purpose, previous studies have not elaborated their hydrological significance. Lichen limits are clearly defined on the sides of rock channels in New England. Australia and they are analyzed in relation to discharge at 6 gauging stations with up to 52 years of continuous record. It is demonstrated that the lowest lichen limit is maintained by peak discharges which occur on average at least once or twice each year. Recurrence intervals based on Annual Series and on Annual Exceedance Series are calculated and for the annual series are fairly consistent for the lowest lichen limit and range from 1·14 to 1·37 years. Lichenometry can be applied to the analysis of river channels in relation to the frequency of peak discharges. By reference to growth curves based upon lichens on Armidale tombstones it is shown that lichenometry may be employed to indicate dates for channel modification due to the removal of blocks and to dam construction and also to date the rock surface between lichen limits. Detailed analysis of the record from gauging stations indicates that where several lichen limits occur in a channel cross section each limit is related to periods when peak discharges exceeded the limits on at least 5 occasions. The lichen‐free surfaces were then recolonized by Parmelia spp. and the size of the lichen thalli indicates the time elapsing since these frequent high discharges.
Bedload stresses and Bagnold's bedform theory for water flows
Authors: Leeder Michael R.
Published: February 2007

Bagnold's theory of bedload stresses and bedforms requires that the tangential stress exerted at the base of a moving bedload dispersion in high stage plane beds is carried entirely by the grain stress T. Derivation of T from experimental data in flow channnels shows, however, that the fluid contribution τ′ is still dominant (≈ 1 to 2 × T). Particle concentrations in the experimental bedload dispersions approached 10 per cent and it is inferred that no appreciable concentration gradient exists. Grain collisions are thought to be most probable whenever more than 1 former stationary grain layer is in forward motion. High stage plane beds may be unstable when grain collisions cease. Current ripples evolve from the amplification and migration of chance defects due to unsteady fluid impulses generated by injection, or burst, phenomena in the viscous sublayer and not through any inherent static shear resistance deficit exerted by stationary bed grains.
The subdivision of a slope profile on the basis of soil properties: A case study from mid‐wales
Authors: Davidson Donald A.
Published: February 2007

Sedimentological analysis of particle size data from a hillslope profile in mid‐Wales allows the identification of two distinct upper slope units. These are described and analyzed in greater detail for clay and organic matter distribution. The original slope subdivision is substantiated by the results and the major differences in soils between the upper units are attributed to drainage contrasts.
Some comments on the quantitative formulation of geomorphological processes in a theoretical model
Authors: Ahnert Frank
Published: February 2007

Quantitative procedures are discussed for the simulation of baselevel lowering, weathering, and several denudation processes within the framework of a three‐dimensional model of landform development Net baselevel lowering is modelled as the outcome of the mass balance at the slope foot Bedrock weathering is seen as a function of waste thickness; a distinction is made between mechanical weathering, with maximum intensity on bare bedrock, and chemical weathering, with maximum intensity under a waste cover thick enough to retain sufficient moisture. Denudation processes considered are splash, viscous flow, plastic flow, and wash‐the latter with a submodel for generating a characteristic spatial distribution of relative runoff discharge. Despite the different empirical results and theoretical considerations that influenced the design of the model equations for these denudation processes, all except suspended load wash denudation produce very similar slope forms. It is shown that these seemingly different equations can be interpreted as special cases of a single general denudation equation.
Modelling drainage headwater development
Authors: Calver A.
Published: February 2007

Processes operative in the divideward sections of streams and channels are reviewed, and the effects of their action over long periods of time are modelled for insight into long‐term valley head development. Upper valley axis profiles eventually become concave upwards over time but may show earlier convexity and convexo‐concavity. After any particular length of development different upper valley axis forms can exist in areas of different climate and hydrological response characteristics.
Simulation of flow geometry in a riffle‐pool stream
Authors: Richards K. S.
Published: February 2007

The nature of the flow in most natural streams is gradually varied rather than uniform. This is particularly true of streams with coarse gravel bed material organized into relatively stable riffle and pool features. In spite of this, there are few applications of the gradually varied flow models (e.g. the Bernoulli equation) to such streams. This paper presents some initial results of a simulation of flow patterns in two riffle‐pool reaches, using an open channel flow profile computation method based on an equation defining an energy balance between successive cross‐sections separated by an incremental distance.
Effect of soil properties on erosion by wash and splash
Authors: Luk S. H.
Published: February 2007

This paper describes laboratory testing of 148 samples collected from Southern Alberta for erosion by wash and splash. Rainfall intensity was held constant during these tests. Soil aggregation was the most significant variable explaining soil loss. The significance of other soil properties, such as organic carbon and clay content is variable, depending on the interrelationships among aggregate stability, organic content, and clay content of particular soils. Variations in erodibility of the major soils examined are explained by the resistance of aggregates to compaction and dispersion. Splash detachment and wash transport are the dominant erosion mechanisms in inter‐rill areas.
‘Bedload’ dynamics: Grain impacts, momentum transfer and derivation of a grain froude number
Authors: Leeder Michael R.
Published: February 2007

A test is proposed for Bagnold's postulate that the normal weight stress due to moving ‘bedload’ is balanced by a solid transmitted stress due to the rate of change of momentum produced by grain impacts on unit area of the stationary bed. The test involves derivation of an expression for normal momentum transfer due to saltating grains at moderate transport stages when grain‐to‐grain collisions and partial suspension during saltation may be ignored. A dimensionless number, Φ, (a grain Froude Number) is derived, given by Ū2/g where Ū is the mean grain forward velocity, g is the gravitational acceleration and L̄ is the length of a single saltation ‘jump’. Equilibrium demands that Φ be unity during bedload transport involving saltating grains if Bagnold's postulate is correct. Experimental data shows Φ < 1, the discrepancy between theory and experiment being due to the existence of lift forces acting upon bedload grains. Bagnold's postulate is correct for concentrated dispersions of grains, as in grain flows, when fluid lift forces may be neglected due to high particle concentration.
Problems in the calibration of an acoustic device for the observation of bedload transport
Authors: Richards K. S. , Milne L. M.
Published: February 2007

Developments in theoretical and empirical modelling of bedload transport processes are hindered by the lack of an adequate data base for testing or establishing the models. Conventional methods of measuring bedload transport rates fail to provide the necessary continuous or frequent record of variations at a single section. Acoustic techniques have the potential to overcome this deficiency, but their application has been very limited. Some of the problems of calibrating an acoustic device in the field and in a laboratory flume are discussed, and a possible circuit design described which might minimize calibration difficulties by automatically subtracting the noise generated by flow turbulence.
Intra‐catchment variability in solute response an east devon example
Authors: Foster I. D. L.
Published: February 2007

Modifications to the land use of a small catchment, including clearance, cultivation and an increase in drainage density, are shown to have influenced a number of solute characteristics. Contrasts are drawn between three source areas; an unmodified subcatchment draining an area of mixed deciduous woodland, and a tile drain system and drainage ditch receiving water from cultivated areas. Not only are the modifications identified in terms of mean solute concentrations, but it is also shown that a change in land use alters the interaction between independent hydrological and meteorological variables, and solute response. A tentative explanation is provided for long term solute behaviour in relation to a number of biological geochemical and hydrological controls.
Factors influencing the growth of miniature ice lenses
Authors: Burt T. P.
Published: February 2007

Experiments involving six soil types indicated that the production of miniature ice lenses is dependent on soil moisture content and grain size with lenses being produced in finer‐grained soils at lower moisture contents than is possible in coarser soils. Explanation of the results involves consideration of the unsaturated hydraulic conductivity of the unfrozen soil through which water migrated to the freezing plane to allow ice lens growth.
A quantitative evaluation of pyrite weathering
Authors: Vear Alwyn , Curtis Charles
Published: February 2007

Namurian sediments at Mam Tor, Derbyshire are cut by a major landslide and a geological fault. Both channel oxygenated waters into fragmented pyritic shales. Pyrite is rapidly oxidized to sulphuric acid, 1.5 g being destroyed by each litre of water passing through the fault‐crush. More than 99 per cent of the acid, however, is immediately consumed in clay‐mineral transformation and carbonate dissolution reactions. The typical acid‐sulphate ‘ochre’ springs thus retain less than 1 per cent of the acid generated in the crush zone. These very rapid and large scale chemical transformations probably contribute to the slide's continuing activity.
Suspended solids concentrations and river water chemistry
Authors: Imeson A. C. , Verstraten J. M.
Published: February 2007

In some rivers concentrations of suspended solids are influenced to a large degree by the chemistry of the river water. This is particularly true for rivers with fine sediments draining areas where soils have high percentages of exchangeable sodium and where changes in the electrolyte concentrations during hydrologic events result in an alternation between conditions favouring dispersion and those favouring flocculation. This relationship is illustrated for low flow conditions by data from a small river in Eastern Australia.

At high flows, variations in suspended solids concentrations independent of those resulting from changes in discharge and erosion are difficult to establish. However, in semi‐arid regions high concentrations of clay and silt may sometimes be transported. The way such concentrations reflect changes in water chemistry is illustrated by a flash flood from Morocco and by data from the Moreau River in South Dakota. A contrasting example from Northern England describes conditions where the water chemistry produces dispersion and high suspended solids concentrations.

The relationship between electrolyte concentration, exchangeable sodium percentage and suspended solids concentrations is described for each drainage basin. Such relationships provide an insight into the nature of erosion processes in a catchment and help to explain why suspended solids concentrations at low flows may be so variable.