bluuebunny/crossref_metadata_2025 huggingface dataset:
Carrier dynamics in non‐polar GaN/AlGaN quantum wells intersected by basal‐plane stacking faults
Authors: Badcock T. J. , Hammersley S. , Kappers M. J. , Humphreys C. J. , Dawson P.
Published: May 2010

We have investigated the recombination dynamics of carriers in non‐polar GaN/AlGaN quantum wells intersected by basal plane stacking faults and an a ‐plane GaN template layer. In the GaN template, both the photoluminescence decay and rise times measured across the basal plane stacking fault emission band increase with decreasing emission energy. This is consistent with a carrier transfer process from less localised to more deeply localised states within the basal plane stacking fault. However, in the quantum well structures this behaviour is suppressed due to the restriction in carrier transport imposed by the quantum wells. We also found that the decay time of the localised exciton emission in the quantum wells is dominated by a non radiative carrier transfer process involving the basal plane stacking faults. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth of low‐dislocation‐density AlGaN using Mg‐doped AlN underlying layer
Authors: Asai T. , Nonaka K. , Ban K. , Nagata K. , Nagamatsu K. , Iwaya M. , Kamiyama S. , Amano H. , Akasaki I.
Published: May 2010

We report on a new technology for growing low‐dislocation‐density AlGaN in which a Mg‐doped AlN underlying layer is used. By growing AlxGa1‐xN on AlN:Mg with AlN molar fractions x of 0.3, 0.5 and 0.7, the density of misfit dislocations is much reduced compared with that in the case of growing AlGaN on undoped AlN. In addition, the surface becomes atomically flat. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Proposed fluvial island classification scheme and its use for river restoration
Authors: Wyrick J. R. , Klingeman P. C.
Published: May 2010

Fluvial islands are present in nearly all natural and regulated rivers. They are important from hydrological, biological, geopolitical and socio‐economic points of view. As ubiquitous as islands are, consideration of islands is relatively absent in most river restoration concepts. The natural river processes that allow for island formation can easily be integrated into typical river classifications. To begin, an island classification scheme is proposed that can become a tool for improved river classifications and restoration projects. In developing an island classification scheme, the objectives are similar to those of previous river classification methods. By observing island characteristics, inductive generalizations may be made about the river's hydrologic and ecologic potential. In river hierarchies, the distinguishing variables used to describe streams were characteristics that could easily be discerned from their appearances, i.e. field‐determinable features. A similar approach is sought for island classification. The distinguishing characteristics of any island may be sorted into three basic categories: those that can be measured from a topographic map or an aerial photograph; those that can be measured in situ at the island and those that can be inferred from either a known history of the island or from the other characteristics of the island. Once all the suitable characteristics were identified, a matrix for island classification was created which can be used to classify island origin and type. The better that the inter‐relationship between island formation, channel processes and watershed processes are understood, the better the natural bio‐physical regime of the river corridor can be identified and incorporated into restoration plans. Copyright © 2010 John Wiley & Sons, Ltd.
Ulysse: a qualitative tool for eliciting mental models of complex systems
Authors: Desthieux Gilles , Joerin Florent , Lebreton Marcel
Published: May 2010

Stakeholders involved in the definition of managerial problems perceive and internalize the complexity of these problems as mental models. These models are not always made explicit, which can lead to misunderstandings and conflicts. This article presents Ulysse, a tool that enables stakeholders to progressively elicit their mental models as causal loop models. Ulysse uses web technologies that store information in a database and interactively display the modeling results. It is based on matrix calculation that facilitates statistical operations and provides better understanding of the model structure. Analysis and comparison of individual models reveal the most important variables and relationships among them as a basis for identifying key issues, divergent and convergent opinions between stakeholders. Ulysse has been tested in the context of regional economic development in Atlantic Canada. The tool was designed to support managers, during interviews, in building qualitative models of indicators. Copyright © 2010 John Wiley & Sons, Ltd.
Matlist: Mature linguistic steganography methodology
Authors: Desoky Abdelrahman
Published: May 2010

The generated text by Natural Language Generation (NLG) and template systems is meaningful and looks legitimate. Therefore, the Mature Linguistic Steganography Methodology (Matlist) employs NLG and template techniques along with Random Series values (RS), e.g. binary, decimal, hexadecimal, octal, alphabetic, alphanumeric, etc., of Domain‐Specific Subject (DSS) to generate noiseless text‐cover. This type of DSS, e.g. financial, medical, mathematical, scientific, economical, etc., has plenty of room to conceal data and allows communicating parties to establish a covert channel such as a relationship based on the profession of the communication parties to transmit a text‐cover. Matlist embeds data in a form of RS values, function of RS, related semantics of RS, a combination of these, etc. Unlike synonym‐based approach, Matlist does not preserve the meaning of text‐cover every time it is used. Instead, Matlist Cover retains different legitimate meaning for each message while it remains semantically coherent and rhetorically sound. The presented implementation, validation, and experimental results demonstrate that Matlist is capable of accomplishing the steganographical goal with higher bitrate than all other linguistic steganography approaches. Copyright © 2010 John Wiley & Sons, Ltd.
Massive clusters: Secondary emission from qkeV to qMeV. New emission processes? New SIMS probe?
Authors: Della‐Negra S. , Depauw J. , Guillermier C. , Schweikert E. A.
Published: May 2010

We report on the secondary ion emission under massive cluster (from 100 to 1600 atoms) impacts from different organic samples. The study has been preformed at the Orsay Tandem Accelerator equipped with a Liquid Metal Ion Source (LMIS) using a time of flight (ToF) mass spectrometer (MS) with a multianode localization detector. The influence of the projectile mass and energy is studied in order to investigate the new hydrodynamic regime of the solid‐particle interaction related to the use of these massive clusters. We shall present this study, the energy range of which extends from 10 qkeV up to 4 qMeV. The results show that the ionic emission intensities increase with the energy and the mass of the projectiles (from n/q = 25 to n/q = 400) which allows the simultaneous emission of a few tens ions of the same mass per impact, what had never before been observed in SIMS. The study of the positive ionic emission is surprising. There is an important emission (also a few tens ions) of H+, H2+, H3+ and C+. The setup permits to determine the angular velocity distributions of the ejected ions. We present the results which permit to distinguish four classes of ionic emission. The molecular ions and molecular clusters are preferentially pushed from the surface by a pressure wave which rises perpendicularly to the beam trajectory. Copyright © 2010 John Wiley & Sons, Ltd.
Performance of using multiple stepwise algorithms for variable selection
Authors: Wiegand Ryan E.
Published: May 2010

Some research studies in the medical literature use multiple stepwise variable selection (SVS) algorithms to build multivariable models. The purpose of this study is to determine whether the use of multiple SVS algorithms in tandem (stepwise agreement) is a valid variable selection procedure. Computer simulations were developed to address stepwise agreement. Three popular SVS algorithms were tested (backward elimination, forward selection, and stepwise) on three statistical methods (linear, logistic, and Cox proportional hazards regression). Other simulation parameters explored were the sample size, number of predictors considered, degree of correlation between pairs of predictors,p‐value‐based entrance and exit criteria, predictor type (normally distributed or binary), and differences between stepwise agreement between any two or all three algorithms. Among stepwise methods, the rate of agreement, agreement on a model including only those predictors truly associated with the outcome, and agreement on a model containing the predictors truly associated with the outcome were measured. These rates were dependent on all simulation parameters. Mostly, the SVS algorithms agreed on a final model, but rarely on a model with only the true predictors. Sample size and candidate predictor pool size are the most influential simulation conditions. To conclude, stepwise agreement is often a poor strategy that gives misleading results and researchers should avoid using multiple SVS algorithms to build multivariable models. More research on the relationship between sample size and variable selection is needed. Published in 2010 by John Wiley & Sons, Ltd.
A Bayesian dose‐finding procedure for phase I clinical trials based only on the assumption of monotonicity
Authors: Whitehead John , Thygesen Helene , Whitehead Anne
Published: May 2010

Despite an enormous and growing statistical literature, formal procedures for dose‐finding are only slowly being implemented in phase I clinical trials. Even in oncology and other life‐threatening conditions in which a balance between efficacy and toxicity has to be struck, model‐based approaches, such as the Continual Reassessment Method, have not been universally adopted. Two related concerns have limited the adoption of the new methods. One relates to doubts about the appropriateness of models assumed to link the risk of toxicity to dose, and the other is the difficulty of communicating the nature of the process to clinical investigators responsible for early phase studies. In this paper, we adopt a new Bayesian approach involving a simple model assuming only monotonicity in the dose‐toxicity relationship. The parameters that define the model have immediate and simple interpretation. The approach can be applied automatically, and we present a simulation investigation of its properties when it is. More importantly, it can be used in a transparent fashion as one element in the expert consideration of what dose to administer to the next patient or group of patients. The procedure serves to summarize the opinions and the data concerning risks of a binary characterization of toxicity which can then be considered, together with additional and less tidy trial information, by the clinicians responsible for making decisions on the allocation of doses. Graphical displays of these opinions can be used to ease communication with investigators. Copyright © 2010 John Wiley & Sons, Ltd.
Functional polymorphism in the GPR55 gene is associated with anorexia nervosa
Authors: Ishiguro Hiroki , Onaivi Emmanuel S. , Horiuchi Yasue , Imai Keiko , Komaki Gen , Ishikawa Toshio , Suzuki Mari , Watanabe Yuichiro , Ando Tetsuya , Higuchi Susumu , Arinami Tadao
Published: May 2010

Endocannabinoids, anandamide, and 2‐arachidonoyl glycerol are involved in food intake and appetite. Although anandamide is now thought to be a ligand for vanilloid receptor, receptors that are targets of anandamide could play a similar role in eating behaviors and related disorders. This study therefore focused on the receptor, which is called G‐protein‐coupled receptor 55 (GPR55) that had recently been reported to have binding affinity for endocannabinoids. Functional analysis of the sole missense polymorphism, rs3749073 (Gly195Val) in the GPR55 gene was performed by detecting the phosphorylation level of extracellular signal‐regulated kinase (ERK) in Chinese‐Hamster‐Ovary (CHO) cells engineered to express human GPR55. Val195 type GPR55 appeared to induce less phosphorylated ERK than Gly195 type GPR55 when CHO cells were treated with anandamide and lysophosphatidylinositol (LPI). An association between the functional Gly195Val polymorphism and anorexia nervosa was tested in a female Japanese population comprising 235 patients and 1244 controls. The Val195 allele and homozygote of the Val195 allele were more abundant in the group of patients diagnosed with anorexia nervosa (P = 0.023, Odds ratio = 1.31 (95% Cl = 1.03–1.37), P = 0.0048, OR = 2.41 (95% Cl = 1.34–4.34), respectively). In conclusion, the low‐functioning Val195 allele of GPR55 appears to be a risk factor for anorexia nervosa. Synapse, 2011. © 2010 Wiley‐Liss, Inc.
Sex differences in the relationship of regional dopamine release to affect and cognitive function in striatal and extrastriatal regions using positron emission tomography and [18F]fallypride
Authors: Riccardi Patrizia , Park Sohee , Anderson Sharlet , Doop Mikisha , Ansari M. Sib , Schmidt Dennis , Baldwin Ronald
Published: May 2010

The purpose of this study was to examine sex differences in the correlations of d‐amphetamine (d‐AMPH) induced displacements of [18F]fallypride in striatal and extrastriatal regions in relation to affect and cognition. Seven male and six female healthy subjects, whose mean age was 25.9 years, underwent positron emission tomography (PET) with [18F]fallypride at baseline and 3 h after a 0.43 mg/kg oral dose of d‐AMPH. Percent displacements in striatal and extrastriatal regions were calculated using regions of interest (ROI) analysis and on a pixel‐by‐pixel basis. Subjects underwent neuropsychological testing prior to the baseline PET study and one hour after d‐AMPH administration for the second PET. In order to examine the subjective effect of d‐AMPH, subjects rated PANAS at baseline and after administration of amphetamine. Correlations of changes in cognition and affect with regional dopamine (DA) release revealed several significant sex related differences. The results of this study demonstrate in vivo sex related differences in the relationship of regional DA release to affect and cognitive function. Synapse 2011. © 2010 Wiley‐Liss, Inc.
Influence of cobalt uptake by Vicia faba seeds on chlorophyll morphosis induction, SOD polymorphism, and DNA methylation
Authors: Rancelis Vytautas , Cesniene Tatjana , Kleizaite Violeta , Zvingila Donatas , Balciuniene Laimute
Published: May 2010

Vicia faba plants show polymorphism to cobalt (Co) excess, expressed by a different degree of chlorophyll morphosis (CM)—from normally green (N) to yellow (Y) seedlings. For superoxide dismutase (SOD), the high V. faba polymorphism was revealed and increased by Co stress. Epigenetic mechanisms may be involved in both phenomena. For such reasons, we investigated the effect of 5‐azacytosine (AzaC) and Na butyrate (NaBut) on CM induction, SOD polymorphism, and DNA methylation–demethylation events in Co(NO3)2 affected plants, without or with AzaC or NaBut. CMs were induced after treatment of seeds for 8 h with 7.5 mM Co(NO3)2 plus 12 h with H2O or 8 h with H2O plus 12 h with Co(NO3)2. In the same order AzaC and NaBut were applied in concentrations equimolar to Co(NO3)2. SOD isoforms were investigated electrophoretically, and for DNA methylation–demethylation events the Aina [Aina et al. (2004) Physiol Plant 121:472–480] system was applied upon using the random amplified polymorphic DNA (RAPD) method employing restrictases MspI and HpaII. The effect of AzaC and NaBut on CM induction in combination with Co was unclear. Posttreatment with Co was more effective than Co‐pretreatment. SOD polymorphism was significantly strengthened by NaBut. Detection of DNA methylation–demethylation events depended on the primers used for RAPD analysis. With AP5 and MP4 primers, DNA demethylation was observed in N‐seedlings after exposure to Co, AzaC or NaBut applied separately. With primer A6, only DNA methylation events were determined in N‐seedlings from seeds exposed to Co or Co‐AzaC, and in Y‐seedlings after Co‐AzaC or Co‐NaBut treatment. UPGMA grouping of the results showed that all N‐seedlings comprised one common cluster after Co exposure, independently of treatment combinations (Co alone, Co with AzaC, Co with NaBut). On the contrary, no significant differences were determined in SOD polymorphism among the most resistant N‐seedlings and the most severely affected Y‐seedlings. © 2010 Wiley Periodicals, Inc. Environ Toxicol 2012.
Detection of umbilical venous constriction by Doppler flow measurement at midgestation
Authors: Hasegawa J. , Mimura T. , Morimoto T. , Matsuoka R. , Ichizuka K. , Sekizawa A. , Okai T.
Published: May 2010

Objectives

To investigate whether umbilical venous velocity and venous velocity pulsation are associated with umbilical vein diameter, umbilical ring diameter and umbilical cord coiling index at midgestation.

Methods

Two hundred and eighty pregnant women were enrolled in the study at between 18 and 24 weeks of gestation. The diameter of the umbilical cord and internal diameter of the umbilical vein in a free loop and at the ring, and the umbilical coiling index, were measured using ultrasonography. Umbilical venous velocities were measured by Doppler ultrasonography at the umbilical ring and a free loop of the cord.

Results

All variables were successfully measured in 92% of the patients. There were negative correlations between the diameters of the umbilical ring and of the umbilical vein at the ring and the venous velocity at the umbilical ring. The venous velocity at the umbilical ring was significantly higher and the umbilical ring diameter was significantly lower in fetuses with umbilical venous pulsation at the free loop. Significant correlations were observed between the venous velocity and amplitude of pulsation. Venous pulsations at the free loop were frequently observed in fetuses with a hypercoiled cord.

Conclusion

High venous velocity and increased venous pulsation at the umbilical ring may be associated with umbilical cord constriction. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
Neural basis of thinking: laboratory problems versus real‐world problems
Authors: Goel Vinod
Published: May 2010

Cognitive psychologists have long argued about the reality and significance of the distinction between well‐structured and ill‐structured problems. Laboratory problems are usually well‐structured, whereas real‐world problems have both well‐structured and ill‐structured components. This article shows how the neuropsychological data reinforce this distinction and suggests how this distinction may help to explain a puzzle about discontinuous performance of some neurological patients in laboratory and real‐world problem situations. Copyright © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

Psychology > Reasoning and Decision Making

Neuroscience > Cognition
Substitutional A‐to‐I RNA editing
Authors: Wulff Bjorn‐Erik , Nishikura Kazuko
Published: May 2010

Adenosine‐to‐inosine (A‐to‐I) editing catalyzed by adenosine deaminases acting on RNA (ADARs) entails the chemical conversion of adenosine residues to inosine residues within double‐stranded RNA (dsRNA) substrates. Inosine base pairs as guanosine and A‐to‐I editing can therefore alter the structure and base pairing properties of the RNA molecule. This has a biological significance in controlling the amount of functional RNA molecules in the cell, in expanding the functionality of a limited set of transcripts, and in defending the cell against certain RNA viruses. A‐to‐I editing is not limited to any specific type of RNA substrate. Instead, it can affect any RNA molecule able to attain the required double‐stranded structure. This includes microRNAs, small interfering RNAs, viral RNAs, and messenger RNAs with potential for recoding events and splice site modifications. Copyright © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

RNA Processing > RNA Editing and Modification
Enzymology of RNA cap synthesis
Authors: Ghosh Agnidipta , Lima Christopher D.
Published: May 2010

The 5′ guanine‐N7 methyl cap is unique to cellular and viral messenger RNA (mRNA) and is the first co‐transcriptional modification of mRNA. The mRNA cap plays a pivotal role in mRNA biogenesis and stability, and is essential for efficient splicing, mRNA export, and translation. Capping occurs by a series of three enzymatic reactions that results in formation of N7‐methyl guanosine linked through a 5′‐5′ inverted triphosphate bridge to the first nucleotide of a nascent transcript. Capping of cellular mRNA occurs co‐transcriptionally and in vivo requires that the capping apparatus be physically associated with the RNA polymerase II elongation complex. Certain capped mRNAs undergo further methylation to generate distinct cap structures. Although mRNA capping is conserved among viruses and eukaryotes, some viruses have adopted strategies for capping mRNA that are distinct from the cellular mRNA capping pathway. Copyright © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

RNA Processing > Capping and 5' End Modifications

RNA Processing > tRNA Processing
Connections between 3′‐end processing and DNA damage response
Authors: Cevher Murat A. , Kleiman Frida E.
Published: May 2010

The cellular DNA damage response (DDR) involves changes in the functional and structural properties of a number of nuclear proteins, resulting in a coordinated control of gene expression and DNA repair. This response includes functional interactions of the DNA repair, transcription, and RNA processing machineries. Following DNA damage, cellular levels of polyadenylated transcripts are transiently decreased and normal recovery depends on transcription‐coupled repair (TCR). In addition, DNA damage has gene‐specific effects regulating the mRNA levels of factors involved in the DDR itself at different times after the damage. The 3′‐end processing machinery, which is important in the regulation of mRNA stability, is involved in these general and gene‐specific responses to DNA damage. The role of 3′‐end processing in DDR supports the idea that the steady‐state levels of different mRNAs change upon DNA‐damaging conditions as a result of regulation of not only their biosynthesis but also their turnover. Here, we review the mechanistic connections between 3′‐end processing and DDR, and discuss the implications of deregulation of this important step of mRNA maturation in the cellular recovery after DNA‐damaging treatment. The relevance of these functional connections is illustrated by the increasing number of reports on this relatively unexplored field. Copyright © 2010 John Wiley & Sons, Ltd.

This article is categorized under:

RNA Interactions with Proteins and Other Molecules > Protein–RNA Interactions: Functional Implications

RNA Processing > 3' End Processing

RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms
A New Example of the Structure Type A2[{Z2R4}X9]: Synthesis and Crystal Structure of Na2[{(ON)Ce4}Cl9]
Authors: Schurz Christian M. , Meyer Monika , Meyer Gerd , Schleid Thomas
Published: May 2010

First single crystals of Na2[{(ON)Ce4}Cl9] were obtained during synthesis attempts for the cerium nitride chloride Ce2NCl3(= {N2Ce4}Cl6). With a molar ratio of 8:10:3 for Ce, CeCl3 and NaN3 along with an excess of the flux NaCl, the mixture obviously contained a small amount of CeOCl that led to the formation of quinary Na2[{(ON)Ce4}Cl9]. It crystallizes in the monoclinic space group P21/m(no. 11) with two formula units in the unit cell with dimensions of a = 813.21(6) pm, b = 1146.13(9) pm, c = 942.86(7) pm and β = 107.504(5) °. As the dominating structural feature {ZCe4}9.5+ tetrahedra are fused through trans‐oriented edges to generate ${}^1_\infty\{\textit{Z}\textrm{Ce}^\textrm{e}_{4/2}\}^{3.5+}$ chains (Z = 1/2 O + 1/2 N) just as in the structurally isotypic compounds A2[{Z2R4}X9] (A = Na, K; R = Pr, Nd, Gd; X = Cl, Br; Z = O, O/N).
Bilateral carpal valgus deformity in hand‐reared cheetah cubs (Acinonyx jubatus)
Authors: Bell Katherine M. , van Zyl Malan , Ugarte Claudia E. , Hartman Angela
Published: May 2010

Four hand‐reared cheetah cubs (Acinonyx jubatus) exhibited progressively severe bilateral valgus deformity of the carpi (CV) during the weaning period. Radiographs of the thoracic limbs suggested normal bone ossification, and serum chemistry was unremarkable. All affected cubs developed CV shortly after the onset of gastroenteritis, which was treated medically, and included use of a prescription diet. A sudden decrease in growth rate was associated with gastrointestinal disease. Before gastroenteritis and CV, affected cubs had higher growth rates than unaffected cubs, despite similar mean daily energy intake. Return to normal thoracic limb conformation was consequent to dietary manipulation (including a reduction in energy intake and vitamin and mineral supplementation), as well as decreased growth rates and recovery from gastroenteritis. The cause of the CV is likely to have been multi‐factorial with potentially complex physiological interactions involved. Zoo Biol 30:199–204, 2011. © 2010 Wiley‐Liss, Inc.
Initiating Physical Therapy on the Day of Surgery Decreases Length of Stay without Compromising Functional Outcomes following Total Hip Arthroplasty
Authors: Juliano Karen , Edwards Danielle , Spinello Daniel , Capizzano Yolanda , Epelman Emie , Kalowitz Jennifer , Lempel Adina , Ghomrawi Hassan
Published: May 2010

In response to rising health care costs, hospitals are implementing clinical pathways in order to standardize care, improve cost efficiency and outcomes. The purpose of this study was to evaluate the effect of initiating physical therapy (PT) on post operative day 1 (POD1) compared to initiating PT on day of surgery (DOS), on length of stay and in-hospital rehabilitation functional outcomes in total hip arthroplasty patients. This change in PT guidelines was part of the implementation of a new multidisciplinary clinical pathway, adopted by the institution in 2007. A retrospective descriptive study of 408 subjects undergoing unilateral THA compared two groups (204 in each group): those who initiated PT on POD1 and those who initiated PT on DOS. Compared to the POD1 group, patients in the DOS group stayed on average 0.21 days less in the hospital. There was no difference in the achievement of functional milestones in spite of the shortened hospitalization. The initiation of a new clinical pathway was successful in reducing mean length of stay while still allowing patients to achieve all necessary functional outcomes, required for discharge home.
Synthesis and Surface‐Active Properties of Uronic Amide Derivatives, Surfactants from Renewable Organic Raw Materials
Authors: Laurent Pascal , Razafindralambo Hary , Wathelet Bernard , Blecker Christophe , Wathelet Jean‐Paul , Paquot Michel
Published: May 2010

Short chemical syntheses were developed to produce a new set of surfactants from uronic acids derived from widely available raw materials. Three different strategies were used to synthesize uronic amide derivatives, the structures of which were totally characterized by spectrometric methods (IR, MS, 1H‐RMN and 13C‐RMN). The best one, using an acid chloride as the synthetic intermediate, furnished the expected amides as a mixture of anomers in 46–58% global yield. Surface‐active properties (CMC, γcmc, Γmax, Amin) of homologous series of uronic acid N‐alkylamides from C8 to C18 were also assessed. In general, these sugar‐based surfactants exhibited good surface‐activities, and appeared as valuable nonionic surfactants compared to octylphenol 9–10 ethylene oxide condensate, the most well‐known nonionic surfactant. Increasing the alkyl chain length influenced the CMC values for both glucuronic and galacturonic N‐alkylamide derivatives. The galacturonic N‐alkylamides decreased γcmc at slower values than their counterpart's glucuronic N‐alkylamides.
Synthesis and Properties of Dissymmetric Gemini Surfactants
Authors: Xu Qun , Wang Liyan , Xing Fenglan
Published: May 2010

A series of novel dissymmetric gemini cationics surfactants was synthesized by three‐step reactions. The dissymmetric gemini surfactants contain a dodecanoic acid dimethylethylamine ester as the constant cationic part on one side of the hydroxypropyl center and a similar other cationic part, but with a different acid length (from octanoic to palmitic), on the other side. The critical micelle concentration (CMC) and the effectiveness of surface tension reduction (γCMC) were determined. The surface tension measurements of dissymmetric gemini surfactants showed good water solubility, and low CMC had great efficiency in lowering the surface tension and a strong adsorption at the air/water interface. The CMC was observed to increase initially with the increase of the ester bond alkyl group. They also showed good foaming properties and wetting capabilites.
A bacterial ortholog of class II lysyl‐tRNA synthetase activates lysine
Authors: Ambrogelly Alexandre , O'Donoghue Patrick , Söll Dieter , Moses Sarath
Published: May 2010

Aminoacyl‐tRNA synthetases produce aminoacyl‐tRNAs, essential substrates for accurate protein synthesis. Beyond their central role in translation some of these enzymes or their orthologs are recruited for alternative functions, not always related to their primary cellular role. We investigate here the enzymatic properties of GenX (also called PoxA and YjeA), an ortholog of bacterial class II lysyl‐tRNA synthetase. GenX is present in most Gram‐negative bacteria and is homologous to the catalytic core of lysyl‐tRNA synthetase, but it lacks the amino terminal anticodon binding domain of the latter enzyme. We show that, in agreement with its well‐conserved lysine binding site, GenX can activate in vitro l‐lysine and lysine analogs, but does not acylate tRNALys or other cellular RNAs.
The post‐illumination chlorophyll fluorescence transient indicates the RuBP regeneration limitation of photosynthesis in low light in Arabidopsis
Authors: Gotoh Eiji , Kobayashi Yoshichika , Tsuyama Michito
Published: May 2010

The mechanism of post‐illumination chlorophyll fluorescence transient (PIFT) was investigated in Arabidopsis. PIFT was detected in the wild type after illumination with low light. In the fba3‐2 (fructose‐1,6‐bisphosphate aldolase) mutant, in which PIFT is enhanced, strong light also induced PIFT. PIFT was suppressed not only in the triose phosphate/phosphate translocator (tpt‐2) mutant, but also in tpt‐2 fba3‐2, suggesting that triose phosphates, such as dihydroxyacetone phosphate (DHAP), are involved in the PIFT mechanism. We concluded that PIFT is associated with ribulose‐1,5‐bisphosphate (RuBP)‐regeneration limitation of photosynthesis in low light.
The antecedents of process integration in business process outsourcing and its effect on firm performance
Authors: Narayanan Sriram , Jayaraman Vaidyanathan , Luo Yadong , Swaminathan Jayashankar M.
Published: May 2010

As service processes become candidates for outsourcing, interest in the global business process outsourcing (BPO) industry has grown considerably. In this study, drawing on information processing theory, we examine the role of integration in BPO and its effect on BPO firm performance. BPO Integration is concerned with the overall coordination of business processes and activities across different units within the outsourced environment. It involves both internal process integration – effective integration of task execution within the BPO and external process integration – effective integration between the BPO and their clients. Using survey data gathered from 205 Indian BPO service providers, we analyze the antecedents of process integration and its impact on BPO performance. The antecedents we examine are task complexity, task security, end customer orientation of the client and IT capability of the BPO. Among other results, we find that both internal and external process integration partially mediate the impact of the antecedents on performance. We draw managerial implications of our research to practicing BPO and client managers on how BPO outsourcing can be made successful.
Climate, agriculture, and cycles of human occupation over the last 4000 yr in southern Zacatecas, Mexico
Authors: Elliott Michelle , Fisher Christopher T. , Nelson Ben A. , Molina Garza Roberto S. , Collins Shawn K. , Pearsall Deborah M.
Published: May 2010

Scholars attribute the growth and decline of Classic period (AD 200–900) settlements in the semi-arid northern frontier zone of Mesoamerica to rainfall cycles that controlled the extent of arable land. However, there is little empirical evidence to support this claim. We present phytolith, organic carbon, and magnetic susceptibility analyses of a 4000-yr alluvial record of climate and human land use from the Malpaso Valley, the site of one such Classic frontier community. The earliest farming occupation is detected around 500 BC and appears related to a slight increase of aridity, similar to the level of the modern day valley. By AD 500, the valley's Classic period Mesoamerican settlements were founded under these same dry conditions, which continued into the Postclassic period. This indicates that the La Quemada occupation did not develop during a period of increased rainfall, but rather an arid phase. The most dramatic changes detected in the valley resulted from the erosion associated with Spanish Colonial grazing and deforestation that began in the 16th century. The landscape of the modern Malpaso Valley is thus primarily the product of a series of intense and rapid transformations that were concentrated within the last 400 yr.
Quaternary glaciations in the Verkhoyansk Mountains, Northeast Siberia
Authors: Stauch Georg , Lehmkuhl Frank
Published: May 2010

Geomorphological mapping revealed five terminal moraines in the central Verkhoyansk Mountains. The youngest terminal moraine (I) was formed at least 50 ka ago according to new IRSL (infrared optically stimulated luminescence) dates. Older terminal moraines in the western foreland of the mountains are much more extensive in size. Although the smallest of these older moraines, moraine II, has not been dated, moraine III is 80 to 90 ka, moraine IV is 100 to 120 ka, and the outermost moraine V was deposited around 135 ka. This glaciation history is comparable to that of the Barents and Kara ice sheet and partly to that of the Polar Ural Mountains regarding the timing of the glaciations. However, no glaciation occurred during the global last glacial maximum (MIS 2). Based on cirque orientation and different glacier extent on the eastern and western flanks of the Verkhoyansk Mountains, local glaciations are mainly controlled by moisture transport from the west across the Eurasian continent. Thus glaciations in the Verkhoyansk Mountains not only express local climate changes but also are strongly influenced by the extent of the Eurasian ice sheets.
Moraine chronosequence of the Donnelly Dome region, Alaska
Authors: Matmon A. , Briner J.P. , Carver G. , Bierman P. , Finkel R.C.
Published: May 2010

We present 10Be exposure ages from moraines in the Delta River Valley, a reference locality for Pleistocene glaciation in the northern Alaska Range. The ages are from material deposited during the Delta and Donnelly glaciations, which have been correlated with MIS 6 and 2, respectively. 10Be chronology indicates that at least part of the Delta moraine stabilized during MIS 4/3, and that the Donnelly moraine stabilized ∼ 17 ka. These ages correlate with other dates from the Alaska Range and other regions in Alaska, suggesting synchronicity across Beringia during pulses of late Pleistocene glaciation. Several sample types were collected: boulders, single clasts, and gravel samples (amalgamated small clasts) from around boulders as well as from surfaces devoid of boulders. Comparing 10Be ages of these sample types reveals the influence of pre/post-depositional processes, including boulder erosion, boulder exhumation, and moraine surface lowering. These processes occur continuously but seem to accelerate during and immediately after successive glacial episodes. The result is a multi-peak age distribution indicating that once a moraine persists through subsequent glaciations the chronological significance of cosmogenic ages derived from samples collected on that moraine diminishes significantly. The absence of Holocene ages implies relatively minor exhumation and/or weathering since 12 ka.
Influence of crop management practices on bean foliage arthropods
Authors: Pereira J.L. , Picanço M.C. , Pereira E.J.G. , Silva A.A. , Jakelaitis A. , Pereira R.R. , Xavier V.M.
Published: May 2010

Crop management practices can affect the population of phytophagous pest species and beneficial arthropods with consequences for integrated pest management. In this study, we determined the effect of no-tillage and crop residue management on the arthropod community associated with the canopy of common beans (Phaseolus vulgaris L.). Abundance and species composition of herbivorous, detritivorous, predaceous and parasitoid arthropods were recorded during the growing seasons of 2003 and 2004 in Coimbra County, Minas Gerais State, Brazil. Arthropod diversity and guild composition were similar among crop management systems, but their abundance was higher under no-tillage relative to conventional cultivation and where residues from the preceding crop were maintained in the field. Thirty-four arthropod species were recorded, and those most representative of the impact of the crop management practices were Hypogastrura springtails, Empoasca kraemeri and Circulifer leafhoppers, and Solenopsis ants. The infestation levels of major insect-pests, especially leafhoppers (Hemiptera: Cicadellidae), was on average seven-fold lower under no-tillage with retention of crop residues relative to the conventional system with removal of residues, whereas the abundance of predatory ants (Hymenoptera: Formicidae) and springtails (Collembola: Hypogastruridae) were, respectively, about seven- and 15-fold higher in that treatment. Importantly, a significant trophic interaction among crop residues, detritivores, predators and herbivores was observed. Plots managed with no-tillage and retention of crop residues had the highest bean yield, while those with conventional cultivation and removal of the crop residues yielded significantly less beans. This research shows that cropping systems that include zero tillage and crop residue retention can reduce infestation by foliar insect-pests and increase abundance of predators and detritivores, thus having direct consequences for insect pest management.
Genetic Diversity and Differentiation among Laboratory and Field Populations of the Soybean Aphid,Aphis glycines
Authors: Michel A.P. , Zhang W. , Mian M.A. Rouf
Published: May 2010

The soybean aphid,Aphis glycinesMatsumura, is a recent invasive pest of soybean in North America. Currently, much research is focused on developing and characterizing soybean cultivars expressing host-plant resistance. During the initial phases of host-plant resistance screening, many of these studies use soybean aphid laboratory populations. Previous studies in other systems have documented substantial differences among laboratory and field populations. Whether or not this pattern exists inA. glycinesis unknown, but it is extremely important when estimating the level of selection and virulence to host-plant resistant soybeans. In this study, we used seven microsatellite markers to estimate and compare genetic diversity and differentiation among five laboratory and 12 field populations. Our results indicate that soybean aphid laboratory populations are severely lacking in genotypic diversity and show extreme genetic differentiation among each other and to field populations. Continued use of laboratory populations for initial soybean aphid resistance screening could lead to erroneous estimations of the potential success for host-plant resistance.
Inequality Amidst Nutritional Abundance: Native Americans on the Great Plains
Authors: Steckel Richard H.
Published: May 2010

The heights of Plains nomads collected by Franz Boas varied by 9 centimeters, following an inverted U-shape by latitude, a pattern also found among Union Army soldiers born east of the Plains. To understand tribal differences, I bring new explanatory variables to the table in the study of historical heights: proxies for effort prices in hunting and gathering food, including biomass, rainfall estimated from tree rings, and tribal area, as well as proximity to trails used by western settlers and movement to reservations. Collectively, these variables explain a substantial share of the systematic variation in average height across tribes.
Translation groups of the boundary-layer flows induced by continuous moving surfaces
Authors: MAGYARI EUGEN
Published: May 2010

The steady plane boundary-layer flows of velocity field {u(x, y), v(x, y)} induced by continuous moving surfaces are revisited in this paper. It is shown that the governing balance equations, as well as the asymptotic condition u(x, ∞) = 0 at the outer edge of the boundary layer are invariant under arbitrary translations y → y + y0(x) of the transverse coordinate y. The wall conditions, i.e. the prescribed stretching velocity u(x, 0) ≡ Uw(x) and the transpiration velocity v(x, 0) ≡ Vw(x) distributions, however, undergo in general substantial changes. The consequences of this basic symmetry property on the structure of the solution space are investigated. It is found that starting with a primary solution which describes the boundary-layer flow induced by an impermeable surface, infinitely many translated solutions can be generated which form a continuous group, the translation group of the given primary solution. The elements of this group describe boundary-layer flows induced by permeable surfaces stretching under transformed wall conditions, Uw(x) → Ũw(x) = u[x, y0(x)] and Vw(x) → Ṽw(x) = v[x, y0(x)] − y′0(x)u[x, y0(x)], respectively. In this way, starting with a known solution {u(x, y), v(x, y)} so that the inverse y0(x) = u−1(x, Ũw) of u[x, y0(x)] exists, a new solution {ũ(x, y), ṽ(x, y)} corresponding to any desired stretching velocity distribution Ũw(x) can be prepared. It also turns out that several exact solutions discovered during the latter decades are not basically new solutions, but translated counterparts of some formerly reported primary solutions. A few specific examples are discussed in detail.
The effect of confinement on the stability of viscous planar jets and wakes
Authors: REES S. J. , JUNIPER M. P.
Published: May 2010

This theoretical study examines confined viscous planar jet/wake flows with continuous velocity profiles. These flows are characterized by the shear, confinement, Reynolds number and shear-layer thickness. The primary aim of this paper is to determine the effect of confinement on viscous jets and wakes and to compare these results with corresponding inviscid results. The secondary aim is to consider the effect of viscosity and shear-layer thickness. A spatio-temporal analysis is performed in order to determine absolute/convective instability criteria. This analysis is carried out numerically by solving the Orr–Sommerfeld equation using a Chebyshev collocation method. Results are produced over a large range of parameter space, including both co-flow and counter-flow domains and confinements corresponding to 0.1 < h2/h1 < 10, where the subscripts 1 and 2 refer to the inner and outer streams, respectively. The Reynolds number, which is defined using the channel width, takes values between 10 and 1000. Different velocity profiles are used so that the shear layers occupy between 1/2 and 1/24 of the channel width. Results indicate that confinement has a destabilizing effect on both inviscid and viscous flows. Viscosity is found always to be stabilizing, although its effect can safely be neglected above Re = 1000. Thick shear layers are found to have a stabilizing effect on the flow, but infinitely thin shear layers are not the most unstable; having shear layers of a small, but finite, thickness gives rise to the strongest instability.
Tangential electroviscous drag on a sphere surrounded by a thin double layer near a wall for arbitrary particle–wall separations
Authors: TABATABAEI S. M. , VAN DE VEN T. G. M.
Published: May 2010

When a charged particle moves along a charged wall in a polar fluid, it experiences an electroviscous lift force normal to the surface and an electroviscous drag, superimposed on the viscous drag, parallel to the surface. Here a theoretical analysis is presented to determine the electroviscous drag on a charged spherical particle surrounded by a thin electrical double layer near a charged plane wall, when the particle translates parallel to the wall without rotation, in a symmetric electrolyte solution at rest. The electroviscous (electro-hydrodynamic) forces, arising from the coupling between the electrical and hydrodynamic equations, are determined as a solution of three partial differential equations, for electroviscous ion concentration (perturbed ion clouds), electroviscous potential (perturbed electric potential) and electroviscous or electro-hydrodynamic flow field (perturbed flow field). The problem was previously solved for small gap widths and low Peclet numbers in the inner region around the gap between the sphere and the wall, using lubrication theory. Here the restriction on the particle–wall distances is removed, and an analytical and numerical solution is obtained valid for the whole domain of interest. For large sphere–wall separations the solution approaches that for the electroviscous drag on an isolated sphere in an unbounded fluid. For small particle–wall distances it differs from that obtained by the use of lubrication theory, showing that lubrication theory is inadequate for electroviscous problems. The analytical results are in complete agreement with the full numerical calculations. For small particle–wall distances a model is given which provides both physical insight and an easy way to calculate the force with high precision.
Editorial
Authors: ASTON ELAINE
Published: May 2010

The academic conference is an important feature of our professional lives. It constitutes a meeting ground, a forum, in which key topics in a field can begin to emerge; where cognate ideas and approaches get debated, affirmed or contested; where, in short, ideas can move (on) through academics being in contact with each other's ideas. Any journal editor is drawn inevitably to the conference ‘season’ as fertile, ‘hunting’ ground; trawls for papers that will yield article publications (if others do not get there first!). And so it is that my second issue of TRI since becoming editor is sourced from the 2008 Actions of Transfer: Women's Performance in the Americas conference, hosted by the University of California, Los Angeles and co-sponsored by the Hemispheric Institute of Performance and Politics. As this event is expertly introduced and the issue framed by co-organizers Sue-Ellen Case and Diana Taylor, this editorial note needs only to be brief. Indeed, I hesitated long at the computer keyboard thinking that perhaps no note at all was necessary. Except that two observations or headlines felt editorially important to me to express: the significance of Actions of Transfer for thinking generally about the nature of the conference event in relation to TRI's international, theatre research remit, and the mix of articles and the performance dossier brought together in the issue.