bluuebunny/crossref_metadata_2025 huggingface dataset:
Prioritization strategies for video storyboard keyframes
Authors: Iyer Hemalata , Lewis Caitlain Devereaux
Published: February 2007

This exploratory study investigates one type of video surrogate, storyboards, in terms of their ability to summarize and communicate the themes of arts‐related videos. An HTML interface containing the storyboards, videos, and instructions was developed and run in a standard browser. Three phases—consisting of storyboard evaluation, full‐length video evaluation, and their comparison—were completed by each user for three different videos. The data were analyzed for issues relating to keywords, summaries, and recognition of visual style for both the storyboards and the full‐length videos. The linear sequence and narrative structure of storyboards are questioned, and a three‐tiered model is proposed. The first layer consists of keyframes representing the “entity” and “action” of the video's central theme, the second layer consists of “entity” and “action” keyframes with regard to background or supporting information, and the third layer is composed of keyframes representing attributes, locations, and time periods. This structure facilitates the identification of appropriate keyframes for storyboards, eliminating redundant or peripheral images, and improves the storyboard's ability to communicate the essential message of videos. The tiered model is motivated and supported by the user study as well as current research on video surrogates and classical indexing theory.
Indecisiveness and response to risk in deciding when to decide
Authors: Patalano Andrea L. , Wengrovitz Steven M.
Published: February 2007

When making decisions, people must determine not only what to choose but also when to choose. Do individuals modulate behavior in response to potential risks associated with delay in determining when to choose? The present work provides evidence that at least one group of people—indecisive individuals—do not. Two process‐tracing studies simulated a 5‐day college‐course selection period in which new course alternatives appeared on each day. In a risk‐free condition, no risks were associated with delay of decision making over the days. In a risk condition, each day of delay was associated with a risk of loss of existing course alternatives. Unlike decisive individuals, who modulated days of deliberation in response to presence versus absence of risk, indecisive individuals did not. The results illustrate not that indecisive individuals show uniformly increased delay relative to others, but rather that their delay behavior may be more striking in its unresponsiveness to risk. Copyright © 2007 John Wiley & Sons, Ltd.
FDR Control by the BH Procedure for Two‐Sided Correlated Tests with Implications to Gene Expression Data Analysis
Authors: Reiner‐Benaim Anat
Published: February 2007

The multiple testing problem attributed to gene expression analysis is challenging not only by its size, but also by possible dependence between the expression levels of different genes resulting from co‐regulations of the genes. Furthermore, the measurement errors of these expression levels may be dependent as well since they are subjected to several technical factors. Multiple testing of such data faces the challenge of correlated test statistics. In such a case, the control of the False Discovery Rate (FDR) is not straightforward, and thus demands new approaches and solutions that will address multiplicity while accounting for this dependency.

This paper investigates the effects of dependency between bormal test statistics on FDR control in two‐sided testing, using the linear step‐up procedure (BH) of Benjamini and Hochberg (1995). The case of two multiple hypotheses is examined first. A simulation study offers primary insight into the behavior of the FDR subjected to different levels of correlation and distance between null and alternative means. A theoretical analysis follows in order to obtain explicit upper bounds to the FDR. These results are then extended to more than two multiple tests, thereby offering a better perspective on the effect of the proportion of false null hypotheses, as well as the structure of the test statistics correlation matrix. An example from gene expression data analysis is presented. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Development of Sequential Multiple Comparison Procedure for Dose Response Test
Authors: Nakamura Tomohiro , Douke Hideyuki
Published: February 2007

We propose a multiple comparison procedure to identify the minimum effective dose level by sequentially comparing each dose level with the zero dose level in the dose finding test. If we can find the minimum effective dose level at an early stage in the sequential test, it is possible to terminate the procedure in the dose finding test after a few group observations up to the dose level. Thus, the procedure is viable from an economical point of view when high costs are involved in obtaining the observations. In the procedure, we present an integral formula to determine the critical values for satisfying a predefined type I familywise error rate. Furthermore, we show how to determine the required sample size in order to guarantee the power of the test in the procedure. In practice, we compare the power of the test and the required sample size for various configurations of the population means in simulation studies and adopt our sequential procedure to the dose response test in a case study. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Step‐up Related Simultaneous Confidence Intervals for MCC and MCB
Authors: Finner Helmut , Strassburger Klaus
Published: February 2007

The derivation of compatible confidence bounds related to stepwise decision procedures is a serious issue. Especially the derivation of step‐up related bounds is rather complex. In this article we consider (one‐sided) multiple comparisons with a control (MCC) and multiple comparisons with the best (MCB) with the aim of establishing δ‐equivalence to the best and derive step‐up related confidence bounds by applying the projection method proposed in Finner and Strassburger (2006). Some examples illustrate the resulting procedures. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Operability Region Equivalence: Simultaneous Confidence Bands for the Equivalence of Two Regression Models over Restricted Regions
Authors: Liu Wei , Hayter Anthony J. , Wynn Henry P.
Published: February 2007

In many scientific problems the purpose of comparing two linear regression models is to demonstrate that they have only negligible differences and so can be regarded as being practically equivalent. The frequently used statistical approach of testing the homogeneity null hypothesis of the two models by using a partialFtest is not appropriate for this purpose. In this paper, a simultaneous confidence band is proposed which provides an upper bound on the largest possible difference between the two models, in units of the standard error of the observations, over a given region of the covariates. This is demonstrated to be a more practical method for assessing the equivalence of the two regression models. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication of nanofibers with antimicrobial functionality used as filters: protection against bacterial contaminants
Authors: Lala Neeta L. , Ramaseshan Ramakrishnan , Bojun Li , Sundarrajan Subramanian , Barhate R.S. , Ying‐jun Liu , Ramakrishna Seeram
Published: February 2007

A comparative study of antimicrobial activity is done using three different electrospun nanofibers namely—CA, PAN, and PVC used as control and with various amounts of AgNO3 being treated with UV‐irradiation leading to the enhancement of silver nanoparticles. DMF is used as the common solvent which helps to undergo spontaneous slow reduction at room temperature to form silver nanoparticles followed by UV‐irradiation using a 400 W source. The time required for the formation of silver nanoparticles is short and they are more or less well dispersed with few such aggregates. The presence of silver nanoparticles is confirmed using various characterization techniques. The antimicrobial activity is studied using nanofibers with fabricated functionality. Biotechnol. Bioneg. 2007;97: 1357–1365. © 2007 Wiley Periodicals, Inc.
An in situ probe for on‐line monitoring of cell density and viability on the basis of dark field microscopy in conjunction with image processing and supervised machine learning
Authors: Wei Ning , You Jia , Friehs Karl , Flaschel Erwin , Nattkemper Tim Wilhelm
Published: February 2007

Fermentation industries would benefit from on‐line monitoring of important parameters describing cell growth such as cell density and viability during fermentation processes. For this purpose, anin situprobe has been developed, which utilizes a dark field illumination unit to obtain high contrast images with an integrated CCD camera. To test the probe, brewer's yeastSaccharomyces cerevisiaeis chosen as the target microorganism. Images of the yeast cells in the bioreactors are captured, processed, and analyzed automatically by means of mechatronics, image processing, and machine learning. Two support vector machine based classifiers are used for separating cells from background, and for distinguishing live from dead cells afterwards. The evaluation of thein situexperiments showed strong correlation between results obtained by the probe and those by widely accepted standard methods. Thus, thein situprobe has been proved to be a feasible device for on‐line monitoring of both cell density and viability with high accuracy and stability. Biotechnol. Bioeng. 2007;97:1489–1500. © 2007 Wiley Periodicals, Inc.
Correlating single cell motility with population growth dynamics for flagellated bacteria
Authors: Arora Sucheta , Bhat Vidya , Mittal Aditya
Published: February 2007

Many bacteria used for biotechnological applications are naturally motile. Their “bio‐nanopropeller” driven movement allows searching for better environments in a process called chemotaxis. Since bacteria are extremely small in size compared to the bulk fluid volumes in bioreactors, single cell motility is not considered to influence bioreactor operations. However, with increasing interest in localized fluid flow inside reactors, it is important to ask whether individual motility characteristics of bacteria are important in bioreactor operations. The first step in this direction is to try to correlate single cell measurements with population data of motile bacteria in a bioreactor. Thus, we observed the motility behavior of individual bacterial cells, using video microscopy with 33 ms time resolution, as a function of population growth dynamics of batch cultures in shake flasks. While observing the motility behavior of the most intensively studied bacteria,Escherichia coli, we find that overall bacterial motility decreases with progression of the growth curve. Remarkably, this is due to a decrease in a specific motility behavior called “running”. Our results not only have direct implications on biofilm formations, but also provide a new direction in bioprocess design research highlighting the role of individual bacterial cell motility as an important parameter. Biotechnol. Bioeng. 2007; 97: 1644–1649. © 2007 Wiley Periodicals, Inc.
Forward and Backward Pericyclic Photochemical Reactions Have Intermediates in Common, Yet Cyclobutenes Break the Rules
Authors: Fuß Werner , Schmid Wolfram E. , Trushin Sergei A. , Billone Paul S. , Leigh William J.
Published: February 2007

Photochemical pericyclic reactions are believed to proceed via a so‐called pericyclic minimum on the lowest excited potential surface (S1), which is common to both the forward and backward reactions. Such a common intermediate has never been directly detected. The photointerconversion of 1,3‐butadiene and cyclobutene is the prevailing prototype for such reactions, yet only diene ring closure proceeds with the stereospecificity that the Woodward–Hoffmann rules predict. This contrast seems to exclude a common intermediate. Using ultrafast spectroscopy, we show that the excited states of two cyclobutene/diene isomeric pairs are linked by not one, but by two common minima, p* and ct*. Starting from the diene side (cyclohepta‐1,3‐diene and cycloocta‐1,3‐diene), electrocyclic ring closure passes via the pericyclic minimum p*, whereas ct* is mainly responsible for cis–trans isomerization. Starting from the corresponding cyclobutenes (bicyclo[3.2.0]heptene‐6 and bicyclo[4.2.0]octene‐7), the forbidden isomer is formed from ct*. The path branches at the first (S2/S1) conical intersection towards p* and ct*. The fact that the energetically unfavorable ct* path can compete is ascribed to a dynamic effect: the momentum in CC twist direction, acquired—such as in other olefins—in the Franck–Condon region of the cyclobutenes.
Controlled synthesis of SrCrO4 crystals with different morphologies
Authors: Yang Xiao‐Hong , Wu Qing‐Sheng , Liu Jin‐Ku
Published: February 2007

Rod‐shape, branch‐shape, bouquet‐shape and claw‐shape SrCrO4 crystals were synthesized through biomembrane/organic‐addition supramolecular templates. The shapes are mainly changed with variance of the organic reagents and organic membranes. Most of the morphologies haven't been reported in the literature. This method may meet with the requirements to synthesize materials of various morphologies and size by using different supramolecular templates. This paper discusses how to control crystals' growth by supramolecular templates. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
DNA Encapsulation Inside Carbon Nanotubes Using Micro Electrolyte Plasmas
Authors: Kaneko T. , Okada T. , Hatakeyama R.
Published: February 2007

DNA encapsulated carbon nanotubes are formed using a plasma ion irradiation method in electrolyte solutions with DNA, which can be regarded as electrolyte plasmas from the view point that the electrolyte solutions consist of positive and negative ions, and neutral particles in the same way as gas phase plasmas. When both the direct current (DC) and radio frequency (RF) electric fields are applied to the DNA electrolyte plasmas through micro gap electrodes, DNA which is negatively charged in solutions tends to change its conformation from random‐coil to stretched‐form by the RF field and be irradiated to the carbon‐nanotube coated anodeelectrode by the DC field. Based on Raman spectroscopy and transmission electron microscopy analyses, DNA is confirmed to be inserted into the carbon nanotubes. The creation of DNA encapsulated carbon nanotubes using the micro electrolyte plasmas supports the validity of the plasma concept extended from gas to liquid phase, which could pioneer novel applications in such nanoelectronics and biomedical fields. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Antimicrobial Treatment of Heat Sensitive Materials by Means of Atmospheric Pressure Rf‐Driven Plasma Jet
Authors: Brandenburg R. , Ehlbeck J. , Stieber M. , v. Woedtke T. , Zeymer J. , Schlüter O. , Weltmann K.‐D.
Published: February 2007

Since several years a number of activities on the field of antimicrobial treatment by using non‐thermal plasmas are known. But although there are quite a few plasma based processes commercially available, the complexity of interaction between plasma and micro organisms prevents the breakthrough of this technology up to now. Thus plasma generation and treatment method needs to be adapted for each individual application. The aim of this work is to demonstrate the industrial applicability of plasma technological processes for medical devices. Therefore a non‐thermal plasma jet operated in argon at atmospheric pressure and driven by radio frequency (27.12 MHz) is applied to antimicrobial treatment of samples made of heat sensitive materials, such as used in medical devices. Due to its compact design and low power consumption, typical 10 W to 60 W, it is predestined for modularisation. Therefore it can be adapted to nearly any geometry such as given by medical devices to be treated. The plasma is characterised by UV/VIS optical emission spectroscopy. In order to analyse the effect of the plasma on the micro organisms (Bacillus atrophaeus spores and Escherichia coli vegetative bacteria) microbiological tests are performed. First results on lethal effects of the plasma treamtent will be discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Production of inflammatory cytokines by peripheral blood monocytes in chronic alcoholism: Relationship with ethanol intake and liver disease
Authors: Laso Francisco Javier , Vaquero José Miguel , Almeida Julia , Marcos Miguel , Orfao Alberto
Published: February 2007

Background:

Controversial results have been reported about the effects of alcoholism on the functionality of monocytes. In the present study we analyze the effects of chronic alcoholism on the intracellular production of inflammatory cytokines by peripheral blood (PB) monocytes.

Methods:

Spontaneous and in vitro‐stimulated production of interleukin (IL) 1α (TNFα) by PB monocytes was analyzed at the single level by flow cytometry in chronic alcoholics without liver disease and active ethanol (EtOH) intake (AWLD group), as well as in patients with alcohol liver cirrhosis (ALC group), who were either actively drinking (ALCET group) or with alcohol withdrawal (ALCAW group).

Results:

A significantly increased spontaneous production of IL1β, IL6, IL12, and TNFα was observed on PB monocytes among AWLD individuals. Conversely, circulating monocytes form ALCET patients showed an abnormally low spontaneous and stimulated production of inflammatory cytokines. No significant changes were observed in ALCAW group as regards production of IL1β, IL6, IL12, and TNFα.

Conclusion:

Our results show an altered pattern of production of inflammatory cytokines in PB monocytes from chronic alcoholic patients, the exact abnormalities observed depending on both the status of EtOH intake and the existence of alcoholic liver disease. © 2007 Clinical Cytometry Society
Potential performance bottleneck in Linux TCP
Authors: Wu Wenji , Crawford Matt
Published: February 2007

Transmission control protocol (TCP) is the most widely used transport protocol on the Internet today. Over the years, especially recently, due to requirements of high bandwidth transmission, various approaches have been proposed to improve TCP performance. The Linux 2.6 kernel is now preemptible. It can be interrupted mid‐task, making the system more responsive and interactive. However, we have noticed that Linux kernel preemption can interact badly with the performance of the networking subsystem. In this paper, we investigate the performance bottleneck in Linux TCP. We systematically describe the trip of a TCP packet from its ingress into a Linux network end system to its final delivery to the application; we study the performance bottleneck in Linux TCP through mathematical modelling and practical experiments; finally, we propose and test one possible solution to resolve this performance bottleneck in Linux TCP. Copyright © 2007 John Wiley & Sons, Ltd.
Gateway performance for network‐controlled WLAN IP mobility
Authors: Rahman Moshiur , Harmantzis Fotios C.
Published: February 2007

‘Always on’ broadband‐accessed network gateway (GW) control can facilitate inter‐WLAN IP mobility, with seamless connectivity. The GW server plays a critical role in the overall WLAN IP (WIP) mobility architecture (IEEE Wireless Communications and Networking Conference,WCNC, Atlanta, GA, 21 March 2004;Int. J. Wireless Inf. Networks2006;13(3):173–192). This paper provides a comparison of WIP with cellular IP (CIP) and mobile IP (MIP), and identifies the main requirements for a broadband‐accessed network‐based GW that supports WIP mobility. The paper then evaluates GW‐contributed handoff message processing delay in the WIP architecture through an analytical system model and OPNET simulation model, and provides a comparison of the GW‐contributed handoff message processing delays for non‐preemptivevspreemptive queuing schemes. Both analytical and simulation results show that WIP handoff message processing delay at the GW has negligible impact on the overall system delay. Finally, this paper presents the simulation results of the fast routing table lookup and forwarding speed on the GW overall performance, which can assist service providers in the challenging implementation issues that they face. Copyright © 2007 John Wiley & Sons, Ltd.
Splice‐isoform specific immunolocalization of neuronal nitric oxide synthase in mouse and rat brain reveals that the PDZ‐complex‐building nNOSα β‐finger is largely exposed to antibodies
Authors: Langnaese Kristina , Richter Karin , Smalla Karl‐Heinz , Krauss Michael , Thomas Ulrich , Wolf Gerald , Laube Gregor
Published: February 2007

Knock out mice deficient for the splice‐isoform αα of neuronal nitric oxide synthase (nNOSαα) display residual nitric oxide synthase activity and immunosignal. To attribute this signal to the two minor neuronal nitric oxide synthase splice variants, ββ and γγ, we generated isoform‐specific anti‐peptide antibodies against the nNOSαα specific ββ‐finger motif involved in PDZ domain scaffolding and the nNOSββ specific N‐terminus. The nNOSαα ββ‐finger‐specific antibody clearly recognized the 160‐kDa band of recombinant nNOSαα on Western blots. Using immunocytochemistry, this antibody displayed, in rats and wild‐type mice, a labeling pattern similar to but not identical with that obtained using a commercial pan‐nNOS antibody. This similarity indicates that the majority of immunocytochemically detectable nNOS is not likely to be complexed with PDZ‐domain proteins via the ββ‐finger motif. This conclusion was confirmed by the inhibition of PSD‐95/nNOS interaction by the nNOSαα ββ‐finger antibody in pull‐down assays. By contrast, nNOSαα ββ‐finger labeling was clearly reduced in hippocampal and cortical neuropil areas enriched in NMDA receptor complex containing spine synapses. In nNOSαα knock out mice, nNOSαα was not detectable, whereas the pan‐nNOS antibody showed a distinct labeling of cell bodies throughout the brain, most likely reflecting ββ/γγ‐isoforms in these cells. The nNOSββ antibody clearly detected bacterial expressed nNOSββ fusion protein and nNOSββ in overexpressing HEK cells by Western blotting. Immunocytochemically, individual cell bodies in striatum, cerebral cortex, and in some brain stem nuclei were labeled in knock out but not in wild‐type mice, indicating an upregulation of nNOSββ in nNOSαα deficient animals. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007
DNA vaccine encoding endosome‐targeted human papillomavirus type 16 E7 protein generates CD4+ T cell‐dependent protection
Authors: Brulet Jean‐Marc , Maudoux Frédéric , Thomas Séverine , Thielemans Kris , Burny Arsène , Leo Oberdan , Bex Françoise , Hallez Sophie
Published: February 2007

Human papillomavirus type 16 is commonly implicated in cervical cancers. The viral genome encodes potential targets like the oncoprotein E7, expressed in transformed cells but thought to represent a poorly immunogenic antigen. We describe in this work a DNA‐based vaccination protocol aimed at inducing an efficient anti‐E7 immune response in vivo. Plasmids allowing the expression of the E7 protein in distinct cellular compartments were generated and assayed in an in vivo model of tumor growth. Our data demonstrate that mice vaccinated with a plasmid encoding for an E7 protein fused to a domain of the MHC class II‐associated invariant chain (IiE7) were protected against tumor challenge. Mice immunized against an ubiquitinated form of E7 (Ub(Ala)E7) failed to control tumor growth. Protection induced by IiE7 was correlated with the development of CD8+ CTL and required the presence of CD4+ cells. In vitro studies confirmed that the IiE7 fusion protein was expressed at high levels in the endosomal compartment of transfected cells, while the natural and the ubiquitin‐modified form of E7 were mainly nuclear. The present study suggests that an efficient anti‐tumor response can be induced in vivo by DNA constructs encoding for E7 protein forms localizing at the endosomal compartment.

See accompanying commentary: http://dx.doi.org/10.1002/eji.200636233
IL‐18 enhances IFN‐γ‐induced production of CXCL9, CXCL10, and CXCL11 in human keratinocytes
Authors: Kanda Naoko , Shimizu Teruo , Tada Yayoi , Watanabe Shinichi
Published: February 2007

IL‐18 is involved in the pathogenesis of atopic dermatitis, psoriasis, and allergic contact dermatitis. CXCL9, CXCL10, and CXCL11 recruit type 1 T cells, and the production of these chemokines by keratinocytes is enhanced in these dermatoses. We examined the in vitro effects of IL‐18 on IFN‐γ‐induced CXCL9, CXCL10, and CXCL11 production in human keratinocytes. IL‐18 enhanced the IFN‐γ‐induced secretion and mRNA expression of CXCL9, CXCL10, and CXCL11 in parallel to the activation of NF‐κB, STAT1, and IFN‐regulatory factor (IRF)‐1. Antisense oligonucleotides against NF‐κB p50, p65, or STAT1 suppressed CXCL9, CXCL10, and CXCL11 production, and antisense IRF‐1 suppressed CXCL11 production. Inhibitors of PI3 K, p38 MAPK, and MEK suppressed IL‐18 plus IFN‐γ‐induced CXCL9, CXCL10, and CXCL11 production and NF‐κB, STAT1, and IRF‐1 activities. IL‐18 induced phosphorylation of ERK and Akt, while IFN‐γ induced phosphorylation of p38 MAPK. These results suggest that IL‐18 may potentiate IFN‐γ‐induced CXCL9, CXCL10, and CXCL11 production in keratinocytes by activating NF‐κB, STAT1, or IRF‐1 through PI3 K/Akt and MEK/ERK pathways. These effects of IL‐18 may promote the infiltration of type 1 T cells into lesions with inflammatory dermatoses and amplify the skin inflammation. IL‐18 may act as a pro‐inflammatory cytokine in these dermatoses and thus is a candidate therapeutic target.
Synthesis and Versatile Reactions of β‐Azidotetraarylporphyrins
Authors: Shen Dong‐Mei , Liu Chao , Chen Qing‐Yun
Published: February 2007

A variety of β‐azidotetraarylporphyrins were conveniently synthesized by classical conversion of the amino groups of β‐aminotetraarylporphyrins into azido groups through diazotization and subsequent treatment with sodium azide. Their thermal reaction and CuI‐catalyzed 1,3‐dipolar cycloaddition with various alkynes were also reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Characterization of Immunological Interactions at an Immunoelectrode by Scanning Electron Microscopy
Authors: Ambrosi Adriano , Morrin Aoife , Killard Anthony J. , Smyth Malcolm R.
Published: February 2007

A method to visualize an immunointeraction occurring at an electrode surface by the use of scanning electron microscopy is demonstrated. A colloidal gold‐labeled antigoat antibody was used for the visualization of two immunosensor platforms where an antiatrazine single chain antibody and an antibiotin were immobilized on the surface, respectively. Firstly, a silver enhancement treatment was optimized in order to improve the visualization of the gold label. Subsequently, protein distribution on the surface was evaluated in relation to the immobilization time. Finally, this method was adopted to evaluate specific immunological interactions. Comparing the images of the immunosensor surfaces with those of different control surfaces, it was established that the immunological interactions were effectively occurring at the electrode and it was also possible to gain an appreciation of the extent and distribution of the immunological interaction at the electrode surface and the level of non‐specific binding occurring. Energy Dispersive X‐ray (EDX) analysis was also performed for a qualitative evaluation of the atomic electrode surface composition.
Colloidal Crystals as Templates for Macroporous Carbon Electrodes of Controlled Thickness
Authors: Reculusa Stéphane , Agricole Béatrice , Derré Alain , Couzi Michel , Sellier Elisabeth , Delhaès Pierre , Ravaine Serge
Published: February 2007

Macroporous carbon films were synthesized using colloidal crystals as a template and were characterized using scanning electron microscopy (SEM) and Raman spectroscopy. The colloidal crystals were elaborated by the Langmuir‐Blodgett technique and were infiltrated with carbon by a controlled chemical vapor infiltration (CVI) process. After removal of the template, thin free‐standing carbon membranes whose thicknesses match perfectly those of the templates were obtained. Their ability to act as electrodes was checked by carrying out cyclic‐voltammetry experiments.
Mass distribution, polydispersity and focusing properties of carrier ampholytes for IEF. III: pH 2.5–4 intervals
Authors: Simó Carolina , Mendieta Martha Elena , Antonioli Paolo , Sebastiano Roberto , Citterio Attilio , Cifuentes Alejandro , Righetti Pier Giorgio
Published: February 2007

To study the molecular mass distribution and number of species in narrow‐range (2‐pH‐unit wide, in the nominal pI 2–4 or 3–5 interval) carrier ampholytes from four commercial sources (Bio‐Lyte, Servalyt, Ampholine and Pharmalyte), a 2‐D technique was adopted, consisting of a preparative focusing step in a Rotofor instrument, followed by analysis of every other collected fraction (10 out of 20) by CE‐MS. It was found that Ampholine pH 3.5–5 contains 105 different molecular mass (Mr) compounds, in theMrinterval 205–965 Da, for a total of 446 isoforms. Bio‐Lyte pH 3–5 consists of 84 differentMrspecies, in theMrrange 216–965 Da, for a total of 383 isoforms. Servalyt pH 2–4 is made of 227 differentMrcompounds, in theMrinterval 204–929 Da, for a total of 1201 isoforms. Pharmalyte pH 2.5–5 comprises 245 amphoteres, in theMrrange 203–857 Da, for a total of 857 isoforms. Pharmalyte appears to be the best brand, with the vast majority of species focusing sharply at their pIposition and almost no ‘poor’ species, distributed along the entire pH gradient, denoting an extremely shallow pH/mobility curve across the pIvalue. Due to some overlap with the adjacent acidic pH 4–6 interval, the species in common have been evaluated: the most extended overlaps are found in Ampholine (55% of the species appearing in the two neighbouring intervals) and in Servalyt (47% coincidence). The lowest overlaps are found in Pharmalyte (23%) and in Bio‐Lyte (20%).
Optimization of an Iron Intercalated Montmorillonite Preparation for the Removal of Arsenic at Low Concentrations
Authors: Masih D. , Izumi Y. , Aika K. , Seida Y.
Published: February 2007

A series of iron intercalated montmorillonites (Fe‐Monts) were prepared using (i) ion exchange of native sodium and calcium ions with iron ions, (ii) base hydrolysis of inserted iron ions in montmorillonite suspension, and (iii) insertion of pre‐hydrolyzed iron colloid in montmorillonite. The materials were characterized by X‐ray diffraction and gas adsorption‐desorption techniques. The basal d(001)‐spacing and BET specific surface area increased after the intercalation of iron species in montmorillonite. Local iron structure studied by X‐ray absorption fine structure (XAFS) spectroscopy showed an unsaturation of the Fe···Fe coordination number (N 2.5) of the intercalated iron species as compared to the bulk iron oxyhydroxides (N 6). The Fe‐Monts were employed for arsenic removal from aqueous solutions at low concentration (0.2–16 mg/L). Among the Fe‐Monts, the one prepared by the hydrolysis of inserted iron ions, was the best in performance. The saturation adsorption amount of the optimized iron‐montmorillonite was 4 and 28 times higher for the removal of arsenite and arsenate, respectively, as compared to bulk iron oxyhydroxide (goethite). Compared with bulk iron oxyhydroxide, the Fe‐Monts were superior for arsenate uptake and comparable for arsenite. In addition, arsenite adsorbed on the Fe‐Monts was found to be oxidized to arsenate based on XAFS spectroscopy.
Development of longitudinal profiles of alluvial channels in response to base‐level lowering
Authors: Begin Ze'ev B. , Meyer David F. , Schumm Stanley A.
Published: February 2007

Degradation of alluvial channels in cohesive sediments was studied in 15 m and 20 m long flumes with a slope of 0°01 cm/cm. Degradation was initiated by lowering base level to a fixed position, and the development of the longitudinal profile of the channel is analysed through a model formulated as a heat (diffusion) equation. It is based on the equation of sediment continuity, combined with an assumption regarding sediment transport, namely that sediment discharge is linearly proportional to the channel slope. In accordance with the boundary and initial conditions imposed by the experimental setup and procedure, the basic equation is amenable to an analytical solution, which defines bed elevation at any distance and time, as a function of the amount of base‐level lowering and a ‘diffusion’ coefficient. Additional problems arising from bank erosion and channel armouring are also treated successfully within the framework of the same model.

The results show that in homogeneous alluvial sediments, not subject to armouring, the ultimate result of base‐level lowering by a certain amount is degradation all along the channel by the same amount. The main impact of erosion is felt in the early stages after initiation of the process, and mainly near the mouth. The rate of degradation at any station along the channel reaches a peak and then slowly decreases with time, and the peak rate is attenuated with distance from the outlet. The model permits the prediction of intermediate stages of profile development at any distance from the outlet and at different times.
A source of bias in rates of surface soil movement as estimated from marked particles
Authors: Caine Nel
Published: February 2007

When estimated from measurements of introduced tracer particles, the rate of surface soil movement tends to be greater than the natural rate for equivalent particles on the same site. This consistent overestimation is greatest in the period following tracer introduction and leads to a measurement bias that may be as high as 300 per cent. The magnitude of the bias decreases with time, as the tracer is incorporated into the surface material, but remains detectable statistically for more than a year on some low‐angle sites.
Channel width—drainage area relations in small basins
Authors: Carragher M. J. , Klein M. , Petch J. R.
Published: February 2007

The measurement of stream channels in basins less than 3 km2 shows compound relations between width and area. Break points in the relations may be attributed to the changing contribution of rapid storm flow and to the effect of bed material size.
Lithologic control of bedrock meander dimensions in the Appalachian Valley and Ridge province
Authors: Braun Duane D.
Published: February 2007

Marked differences in bedrock meander dimensions in the Appalachian Valley and Ridge province, at times in adjacent reaches of a single stream, are related to differences in relative erodability of the bedrock. Meanders cut in thick‐bedded to massive lithologies, typically carbonates, are distinctly smaller overall than meanders cut into shaly lithologies.

Other factors that could affect bedrock meander dimensions were considered and none appeared to offer any help in explaining the dimensional differences observed above.

In plateau regions underlain by essentially horizontal strata, the meander form characteristic of one lithology may become superimposed upon another as incision progresses, producing anomalous relationships between bedrock meander dimensions and lithology.

Empirical relations developed from meander geometry measurements and estimated bedrock erodability for 78 bedrock meander reaches, containing a total of 1089 individual meander loops, show that meanders cut in shaly lithologies (ML = 105 Q0.50f, where ML = meander length and Qf = most probable annual flood) are about twice the length of meanders cut in non‐shaly lithologies (ML = 39.30.56f). The valley floor width of the meanders cut in shaly bedrock (VF = 28 Q0.43f) is two to three times wider than the valley floor width of the meanders cut in the more resistant non‐shaly bedrock (VF = 8 Q0.43f). The mean and median meander length values for individual reaches typically differ by less than 10 per cent.
A linear erosion/elevation measuring instrument (LEMI)
Authors: Toy Terrence J.
Published: February 2007

The Linear Erosion/Elevation Measuring Instrument (LEMI) offers an alternative to erosion pins for assessing changes in the ground surface that need not disturb the soil at the point of measurement. The device, fabricated from two carpenter's levels, is mounted on each of a series of support rods implanted along a hillslope profile. The vertical distance between the LEMI and the surface may be recorded to the nearest one‐half millimetre. Testing indicates that the use of the LEMI sacrifices about one millimetre of measurement replicability while obtaining undisturbed site data.
Stratigraphic evidence of episodic talus accumulation on the isle of skye, Scotland
Authors: Innes John L.
Published: February 2007

Evidence of episodic development of alluvial talus is given. Three phases of accumulation are identified within the last 3000 years. Average rates of accumulation range from 0·2–1·7 mm yr−1 during each period. Conventional models relating climate to slope activity are inappropriate due to the local conditions.
Geo‐botanical evidence of late quaternary mass wasting in block field areas of Virginia
Authors: Hupp Cliff R.
Published: February 2007

Studies of block fields at Massanutten Mountain, Virginia, document and provide information on the magnitude and frequency of mass movement on these coarse‐grained slopes. Block fields, which traditionally have been considered relicts of Pleistocene climate, occur on and downslope from resistant Massanutten Sandstone in Passage Creek basin. Slopes are strewn with boulders and vegetative cover on the open block fields is absent to sparse. Several block fields were investigated for evidence of recent movement using the degree of lichen growth, differences in block weathering, and rock‐fall damaged trees. Temporal and spatial aspects of geomorphic processes can be inferred through dendrogeochronology. Corrasion scars and stem ages infer a minimum age for a geomorphic or hydrologic event. High flows on Passage Creek coincided with tree‐ring determined dates of block‐field movement. Although, Pleistocene periglacial climate may have facilitated original formation of block fields, some block fields now continue to spread downslope during intense runoff events. Present block‐field mass wasting may be the principal erosional process in these areas of resistant rock.
Quantimet image analysis of soil pore geometry: Comparison with tracer breakthrough curves
Authors: Walker P. J. C. , Trudgill S. T.
Published: February 2007

The relationships between two‐dimensional image analysis of soil thin‐sections and tracer breakthrough curves has been studied for a silty clay loam brown earth soil under saturated conditions. Initial tracer breakthrough is well in advance of one pore volume. Discrepancies between Quantimet image analysis and breakthrough curve characterization were related by inference to the role of infrequently occurring macropores not necessarily sampled on the two‐dimensional images. A fundamental difficulty found in the use of image analysis is the uncertain nature of the relationship between the two‐dimensional image and the three‐dimensional pore system. Caution is needed in using Quantimet image analysis to describe gross properties of the three‐dimensional pore system.
Variation in cross‐sectional asymmetry of coarse bedload river channels
Authors: Milne J. A.
Published: February 2007

Alternative indices of cross‐section asymmetry are compared. Observed values of two preferred indices for 567 natural sections across eleven confined upland channels are predictably low along such low sinuosity reaches. Variation in asymmetry of sections located around confined, unconfined but stable, and freely‐migrating bends is evaluated. Consideration of the influence of bed topography emphasizes local plan curvature of bed forms as an important control on degree of asymmetry. Variation in indices for bed forms in similar planform locations indicates the levels of asymmetry at different stages of the transformation of channel geometry over time.
Eolian processes in alpine belts of the high Tatra mountains, Poland
Authors: Izmailow Bogdana
Published: February 2007

Eolian processes were the subject of detailed studies in the high‐mountain area of the Tatra Mts. The field investigations in 1975–80 attempted to determine the amount of deflation and eolian deposition and to improve understanding of their mechanism. The net rates of these processes were determined from repeated survey of deflational forms and of eolian deposits. Observations of the mechanism of material displacement were based on field experiments carried out during strong winds. All the investigations were conducted using simple methods and traps. Relationships between the course and intensity of processes and wind conditions and soil properties were obtained.
Geomorphological response to an extreme flood: A case from southeast Spain
Authors: Harvey A. M.
Published: February 2007

On 28–29 September 1980 an extreme storm of 150 mm of rain in c. 5 hours caused a flash flood near Tabernas in a semi‐arid area in southern Spain. With the rainfall total approximating the mean annual rainfall the recurrence interval is estimated to be 25–100 years. Flood peak discharges have been estimated from a mountain source area across an alluvial fan and the geomorphological response to the storm described. Channel adjustment differed between channels in the fanhead trench and those unconfined channels on the fan surface. The implications of the spatial pattern of erosional an depositional feaures for landform adjustment in semi‐arid regions are discussed.
En masse debris transport in a mountain stream
Authors: Ackroyd Peter , Blakely Robert J
Published: February 2007

Accumulations of stored sediments in a sub‐alpine environment of a front range of New Zealand's Southern Alps closely resemble sieve deposits previously described from southeastern California.

The locations of such deposits, within active river channels, has important implications for long term sediment yields from catchments where such deposits occur. The catastrophic failure of a sieve deposit in the Torlesse Stream catchment, the site of an earlier investigation of mountain stream sediments, resulted in a sediment yield equivalent to a third of the total yield recorded over an eight‐year period. Derived bed‐load transport rates represent, at a minimum, a four‐fold increase over calculated average transport rates.

Such deposits are only likely to fail during extreme low frequency events since their highly permeable gravels allow for the continuation of stream flow underneath the bulk of the deposit and restricts significant increases in moisture content within the deposit. The loss of water is responsible for the inhibition of flowage‐type mass movement transport mechanisms wherein available water contributes to the maintenance of positive pore pressures.

For the example studied here the percentage of silt and clay is less than 3 per cent of the total sample while sorting values (σ1) are generally less than 2.0ϕ. These values are approximately one‐third and one‐half respectively, of typical values obtained for these parameters from debris flow deposits. The feature described here is believed to have originated through failure of a higher altitude perched scree‐field. This mode of origin would account for the distinctive sediment size parameters.
Drainage basins as process‐response systems: An example from Central Macedonia, North Greece
Authors: Astaras Theodore
Published: February 2007

Study of two subareas of the same large basin in North Greece determined that differences in processes and form exist between the two subareas. These differences were brought on by man's interference upon one of the subareas.

In area A, seminatural vegetation promotes throughflow and protects the surface from overland flow. Hence, natural erosion takes place primarily by channel deepening and infall of side slopes into the channels.

In area B, clearing of the seminatural vegetation and the improper ploughing for cultivation increases the overland flow which promotes slope erosion but the augmented debris supply has checked channel erosion. These processes change the form of the drainage basins of the area.
Using parabolas to describe the cross‐sections of glaciated valleys
Authors: Wheeler Dennis A.
Published: February 2007

It is widely accepted that the simple power curve Y = aXb can be used to describe the cross‐section of glaciated valleys. There are, however, good reasons to suppose that this particular form of equation is inappropriate for this purpose.
Soil carbon dioxide and weathering potentials in tropical karst terrain, peninsular Malaysia: A preliminary model
Authors: Crowther J.
Published: February 2007

CO2 concentrations at depths of 15,30, and 50 cm were determined over a one‐year period in six karst soils in the Malay peninsula. Evidence suggests that the highest single CO2 value (MAXCO2, per cent) recorded at each site/depth provides the best estimate of conditions during groundwater recharge events. Soil depth (cm) and bulk density (BDEN) are the best predictors of MAXCO2, with the equation loglo(MAXCO2) = 1·146 (BDEN) + 0·00698 (DEPTH) ‐ 1·227 accounting for 86 per cent of the variation. This equation is used to model MAXCO2 at seven, more remote sites. Soil throughflow patterns and groundwater recharge points are estimated from slope pantometer and soil depth surveys in order to assess the CO2 concentration with which soil waters ultimately equilibrate before entering the limestone. Limestone weathering seems to be predominantly of the open system type, the overall mean MAXCO2 of 1·65 per cent corresponding with a weathering potential of 167 ppm CaCO3. Weathering potentials vary markedly, ranging from 62–82 ppm on rocky hilltops to more than 280 ppm on certain tower karst footslopes in Selangor and the Kinta Valley and on moderate hillslopes developed in impure limestones in the Boundary Range.
Characteristics and origins of lee‐side stratification sequences in late pleistocene drumlins, northern Ireland
Authors: Dardis George F. , McCabe A. Marshall , Mitchell W. Ian
Published: February 2007

Spindle‐ and parabolic‐shaped drumlins examined at fifty‐five localities in northern Ireland possess stratification sequences on their lee‐side flanks. These forms lack the distinctive steep stoss‐ and tapering lee‐ends of classical drumlins and tend to occur in linear zones transverse to late Pleistocene ice‐flow. In most cases (90 per cent) the stratified deposits infill embayments excavated in the lee‐side of barkhanoid forms and, in the remainder (10 per cent), they are superimposed on the lee‐side of whaleback forms. The stratification sequences developed as a result of sedimentation in interconnected subglacial water‐filled cavities and are unlike remanie proglacial sediments moulded by ice into drumlin form. Stratigraphic evidence indicates that the lee‐side sequences developed during drumlin streamlining, which supports the view that subglacial hydraulic processes played an important role in drumlin formation.
The survival of desert varnish in subsurface positions, western New South Wales, Australia
Authors: Dragovich D.
Published: February 2007

Desert varnish occurs in arid western New South Wales. Microprobe analysis has shown that the chemical composition of this varnish lies within the ranges reported for varnish in United States. Field observations suggest that desert varnish near the soil surface may be destroyed by weathering, but that varnish at depths of more than 15 cm can survive burial and later be exhumed. Varnish has also survived coating by calcium carbonate; a corrected age of about 5000 years for the carbonate indicates long‐term persistence of varnish under this form of ‘burial’. In some situations, presently‐exposed varnish may have a complex history of burial and exhumation following initial subaerial formation.