bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical generation and grid controls of boundary‐fitted conformal grids in multiply connected regions
Authors: Tsay Ting‐Kuei , Wang John , Huang Yung‐Te
Published: February 2006

Based on the study of grid generation methods in a simply connected region (Int. J. Numer. Meth. Engng 1997; 40:343), with the aid of a new transformation from a multiply connected region to a simply connected domain, the grid generation in a multiply connected domain is carried out in this paper. 2‐D conformal and orthogonal grids are generated in a multiply connected region, mostly involving a multiple‐blocks method developed in the present study. To avoid grid distortion on the degenerated boundary caused by physical singularities, controls of grids through specified points are implemented, without losing the conformal properties. Further applications of this grids‐controlling technique for points inside the region, the nested grids, and the multiple‐blocks method are introduced and discussed comprehensively. Numerical examples are taken to demonstrate the validity and applicability of the theorems. Copyright © 2006 John Wiley & Sons, Ltd.
High‐order finite elements applied to the discrete Boltzmann equation
Authors: Düster Alexander , Demkowicz Leszek , Rank Ernst
Published: February 2006

A discontinuous Galerkin approach for solving the discrete Boltzmann equation is presented, allowing to compute approximate solutions for fluid flow problems. Based on a two‐dimensional high‐order finite element and an explicit Euler time stepping scheme, the D2Q9 model is discretized and the results are compared to the exact solution of the Navier–Stokes equation. Four numerical examples are considered, including stationary and instationary problems with curved boundaries. It is demonstrated that the proposed method allows to obtain the desired, highly efficient exponential convergence. Copyright © 2006 John Wiley & Sons, Ltd.
Multiple crack weight for solution of multiple interacting cracks by meshless numerical methods
Authors: Muravin Boris , Turkel Eli
Published: February 2006

We devise a multiple crack weight (MCW) method for the accurate and effective solution of strongly interacting cracks by meshless numerical methods. The MCW method constructs weight functions around cracks so that they simultaneously characterize all the cracks present in the single nodal domain of influence. This approach reduces the number of nodes necessary to achieve sufficient accuracy and consequently it decreases the computational effort. Numerical examples demonstrate that the method allows an accurate solution of multiple cracks problems. Convergence of the method is analysed and discussed. Copyright © 2006 John Wiley & Sons, Ltd.
A novel heterozygous missense mutation 377T > C (V126A) of TGIF gene in a family segregated with holoprosencephaly and moyamoya disease
Authors: Chen Ming , Kuo Shou‐Jen , Liu Chin‐San , Chen Wei‐Liang , Ko Tsang‐Ming , Chen Tze‐Ho , Chang Shun‐Ping , Huang Chien‐Hao , Chang Yih‐Yuan , Wang Bao‐Tyan
Published: February 2006

Objectives

to identify whether any mutations of candidate genes including SHH, ZIC2, SIX3, and TGIF exist in a Taiwanese family segregated with holoprosencephaly (HPE) and moyamoya disease.

Methods

Genotypes of the candidate genes SHH, ZIC2, SIX3, and TGIF were determined in the family members who were available for analysis by sequencing. In addition, genomic regions of another 50 unrelated Taiwanese (100 chromosomes) were studied to verify whether the nucleotide changes we found were mutations or polymorphisms.

Results

A novel missense mutation 377T > C and two polymorphisms (420A > G and 487C > T) in the TGIF gene were identified. No mutations in SHH, ZIC2 and SIX3 were found. The mother of the three HPE fetuses was found to be afflicted with moyamoya disease. A brief review of the mutations as well as polymorphisms reported in the TGIF gene up to 2005 is given.

Conclusion

Molecular diagnosis can help genetic counseling in HPE, which is a heterogeneous disorder with its phenotypic and genotypic spectrum highly widened and variable. The possible association between TGIF mutation and moyamoya disease noted in our study also appeared to be novel. Copyright © 2006 John Wiley & Sons, Ltd.
Prenatal diagnosis of citrullinemia and argininosuccinic aciduria: evidence for a transmission ratio distortion in citrullinemia
Authors: Kleijer Wim J. , Garritsen Victor H. , van der Sterre Marianne L. T. , Berning Christoph , Häberle Johannes , Huijmans Jan G. M.
Published: February 2006

Background

In the course of 25 years, we have experienced a high rate of affected fetuses in the prenatal diagnosis of citrullinemia.

Methods and Results

Ninety‐one pregnancies at 1 in 4 risk were tested; 36 were diagnosed as affected (39.5%; P = 0.0015). The high rate of positive diagnoses was found both after chorionic villus sampling (24/68 = 35.3%) and amniocentesis (12/23 = 52.2%) despite the completely different and independent techniques used. Using exactly the same (indirect) enzyme assay for argininosuccinic aciduria on chorionic villi and a similar method on amniotic fluid, the expected rate of affected fetuses was found: 13/53 = 24.5%. Technical and genetic causes for the unexpected results were excluded by confirmatory studies performed on independent fetal material, which was available for 27 of the 36 fetuses affected with citrullinemia. Biochemical confirmation was obtained in the 27 cases, whereas in 18 fetuses homozygosity or compound heterozygosity for disease‐causing mutations were retrospectively demonstrated in the stored fetal cells.

Conclusion

The results suggest the occurrence of preferential transmission of the mutant allele. An explanation for this phenomenon may be found in a protective role of argininosuccinic acid synthetase deficiency in mutant sperm cells against the possibly detrimental or apoptotic effect of nitric oxide produced normally from arginine by nitric oxide synthase. Copyright © 2006 John Wiley & Sons, Ltd.
Attitudes towards prenatal diagnosis and termination of pregnancy for thalassaemia in pregnant Pakistani women in the North of England
Authors: Ahmed Shenaz , Green Josephine M. , Hewison Jenny
Published: February 2006

Objectives

Most births of children affected with β‐thalassaemia major in the United Kingdom are to parents of Pakistani origin. A popular explanation for this is that Pakistanis decline termination of pregnancy on religious grounds. However, various factors influence people's attitudes towards prenatal diagnosis and termination of pregnancy, which have not been investigated in a UK Pakistani sample. This study is aimed at exploring the attitudes of pregnant Pakistani women towards prenatal diagnosis and termination of pregnancy for β‐thalassaemia major in the North of England.

Methods

Forty‐three pregnant women tested for thalassaemia carrier status were interviewed following receipt of their test results. Interviews were analysed using the grounded theory approach.

Results

Findings showed: (1) women's awareness of and attitudes towards prenatal diagnosis; (2) the relationship between attitudes towards prenatal diagnosis and termination of an affected foetus; (3) the relationship between attitudes towards termination of pregnancy and religious beliefs, perceptions of severity of the condition, influence of significant others, and (4) the impact of gestational age at the time of the offer of termination of pregnancy.

Conclusions

Pakistani women's attitudes towards prenatal diagnosis and termination of pregnancy are influenced by various factors, and therefore their religion should not be taken as a proxy for their attitudes either for or against termination of pregnancy. Copyright © 2006 John Wiley & Sons, Ltd.
Prenatal diagnosis of achondroplasia presenting with multiple‐suture synostosis: a novel association
Authors: Karadimas Charalampos , Trouvas Dimitrios , Haritatos George , Makatsoris Constantinos , Dedoulis Evangelos , Velissariou Voula , Antoniadi Thalia , Hatzaki Angeliki , Petersen Michael B.
Published: February 2006

Objective

We report an atypical case of a fetus presenting with a combined achondroplasia and multiple craniosynostosis phenotype.

Methods

Sonographic monitoring in conjunction with molecular genetic analysis was performed in a 32‐gestational weeks fetus.

Results

Sonographic findings were consistent with a diagnosis of achondroplasia associated with multiple‐suture synostosis. The most common G380R FGFR3 achondroplasia mutation was detected.

Conclusion

The most common achondroplasia mutation should be considered for prenatal DNA testing in cases with ultrasound findings of achondroplasia and multiple‐suture synostosis. This is crucial for the genetic counselling and perinatal management of the fetus. Copyright © 2006 John Wiley & Sons, Ltd.
Proteomic analysis of membrane microdomains derived from both failing and non‐failing human hearts
Authors: Banfi Cristina , Brioschi Maura , Wait Robin , Begum Shajna , Gianazza Elisabetta , Fratto Pasquale , Polvani Gianluca , Vitali Ettore , Parolari Alessandro , Mussoni Luciana , Tremoli Elena
Published: February 2006

Eukaryotic cells plasma membranes are organized into microdomains of specialized function such as lipid rafts and caveolae, with a specific lipid composition highly enriched in cholesterol and glycosphingolipids. In addition to their role in regulating signal transduction, multiple functions have been proposed, such as anchorage of receptors, trafficking of cholesterol, and regulation of permeability. However, an extensive understanding of their protein composition in human heart, both in failing and non‐failing conditions, is not yet available. Membrane microdomains were isolated from left ventricular tissue of both failing (n = 15) and non‐failing (n = 15) human hearts. Protein composition and differential protein expression was explored by comparing series of 2‐D maps and subsequent identification by LC‐MS/MS analysis. Data indicated that heart membrane microdomains are enriched in chaperones, cytoskeletal‐associated proteins, enzymes and protein involved in signal transduction pathway. In addition, differential protein expression profile revealed that 30 proteins were specifically up‐ or down‐regulated in human heart failure membrane microdomains. This study resulted in the identification of human heart membrane microdomain protein composition, which was not previously available. Moreover, it allowed the identification of multiple proteins whose expression is altered in heart failure, thus opening new perspectives to determine which role they may play in this disease.
Analysis of chicken serum proteome and differential protein expression during development in single‐comb White Leghorn hens
Authors: Huang San‐Yuan , Lin Jyh‐Hung , Chen Yu‐Huey , Chuang Chin‐Kai , Chiu Yu‐Fang , Chen Ming‐Yu , Chen Hsin‐Hsin , Lee Wen‐Chuan
Published: February 2006

Serum is believed to harbor thousands of distinct proteins that are either actively secreted or leak from various blood cells or tissues. Exploring protein composition in serum may accelerate the discovery of novel protein biomarkers for specific economic traits in livestock species. This study analyzed serum protein composition to establish a 2‐DE reference map, and monitored protein dynamics of single‐comb White Leghorn hens at 8, 19 and 23 weeks after hatching. A total of 119 CBB‐stained and 315 silver‐stained serum protein spots were analyzed by MALDI‐TOF MS. Of these, 98 CBB‐stained and 94 silver‐stained protein spots were significantly matched to existing chicken proteins. The identified spots represented 30 distinctive proteins in the serum of laying hens. To compare protein expression during development, expression levels of 47 protein spots were quantified by relative spot volume with Melanie 3 software. Ten protein spots increased and 3 protein spots decreased as hen age increased. Previous research has suggested that some of these proteins play critical roles in egg production. The differentially expressed proteins with unknown identities will be valuable candidates for further explorations of their roles in egg production of laying hens.
Comparison of the Paul ion trap to the linear ion trap for use in global proteomics
Authors: Riter Leah S. , Gooding Karen M. , Hodge Barry D. , Julian Randall K.
Published: February 2006

A critical evaluation of the performance of a 2‐D linear ion trap (IT) instrument to two 3‐D quadrupole IT instruments with emphasis on identification of rat serum proteins by bottom‐up LC‐MS/MS is presented. The speed and sensitivity of each of the instruments were investigated, and the effects that each of these have on the bottom‐up proteomics identification approach are discussed.
2‐DE proteome analysis of a proliferating and differentiating human neuronal stem cell line (ReNcell VM)
Authors: Hoffrogge Raimund , Mikkat Stefan , Scharf Christian , Beyer Susanne , Christoph Hilmar , Pahnke Jens , Mix Eilhard , Berth Matthias , Uhrmacher Adelinde , Zubrzycki Igor Z. , Miljan Erik , Völker Uwe , Rolfs Arndt
Published: February 2006

The proteome of a proliferating human stem cell line was analyzed and then utilized to detect stem cell differentiation‐associated changes in the protein profile. The analysis was conducted with a stable human fetal midbrain stem cell line (ReNcell VM) that displays the properties of a neural stem cell. Therefore, acquisition of proteomic data should be representative of cultured human neural stem cells (hNSCs) in general. Here we present a 2‐DE protein‐map of this cell line with annotations of 402 spots representing 318 unique proteins identified by MS. The subsequent proteome profiling of differentiating cells of this stem cell line at days 0, 4 and 7 of differentiation revealed changes in the expression of 49 identified spots that could be annotated to 45 distinct proteins. This differentiation‐associated expression pattern was validated by Western blot analysis for transgelin‐2, proliferating cell nuclear antigen, as well as peroxiredoxin 1 and 4. The group of regulated proteins also included NudC, ubiquilin‐1, STRAP, stress‐70 protein, creatine kinase B, glial fibrillary acidic protein and vimentin. Our results reflect the large rearrangement of the proteome during the differentiation process of the stem cells to terminally differentiated neurons and offer the possibility for further characterization of specific targets driving the stem cell differentiation.
Titanium‐mediated living radical styrene polymerizations. VI. Cp2TiCl‐catalyzed initiation by epoxide radical ring opening: Effect of the reducing agents, temperature, and titanium/epoxide and titanium/zinc ratios
Authors: Asandei Alexandru D. , Moran Isaac W. , Saha Gobinda , Chen Yanhui
Published: February 2006

The effects of the reducing agent, temperature, and epoxide/Ti and Ti/Zn ratios were investigated for the Cp2TiCl‐catalyzed living radical polymerization of styrene initiated by epoxide radical ring opening. No reduction of bis(cyclopentadienyl)titanium dichloride occurred with Cu, Devarda's alloy, Ni, Ce, Cr, Sn, Mo, and ascorbic acid, whereas Al, lithium nitride, Mn, Sm, and Fe led to free‐radical or poorly controlled polymerizations. The best results were obtained with Zn alloy, powder, or nanoparticles. Nano‐Zn provided the lowest polydispersity index values, highest initiator efficiency (IE), and fastest reaction rate while maintaining a well‐defined living polymerization. Progressively lower polydispersity was obtained with an increasing excess of Zn with an optimum at Cp2TiCl/Zn = 1/2. This was rationalized through the heterogeneous nature of Zn and its possible involvement in the reversible termination step. The polymerization was insensitive to light or dark conditions, and a linear dependence of Mn on the conversion was observed at all temperatures in the 60–130 °C range with an optimum at 70–90 °C. A stoichiometric 1/2 epoxide/Ti ratio provided low polydispersity (weight‐average molecular weight/number‐average molecular weight < 1.2) and high IE, whereas increasing the epoxide/Ti ratio to 1/3 maintained a low polydispersity index but decreased the IE. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2156–2165, 2006
Lung inflammation in preterm infants with respiratory distress syndrome: Effects of ventilation with different tidal volumes
Authors: Lista Gianluca , Castoldi Francesca , Fontana Paola , Reali Roberta , Reggiani Alessandro , Bianchi Silvia , Compagnoni Gilberto
Published: February 2006

Ventilation with an inappropriate tidal volume (Vt) triggers lung inflammation, an important predisposing factor of bronchopulmonary dysplasia. It still remains uncertain what the appropriate starting target Vt should be during the acute phase of respiratory distress syndrome (RDS). Our aim was to evaluate lung inflammation in preterm infants undergoing synchronized intermittent positive‐pressure ventilation (SIPPV) with two different tidal volumes Vt during the acute phase of RDS. Thirty preterm infants (gestational age, 25–32 weeks) with acute RDS were randomly assigned to be ventilated with Vt = 5ml/kg (n = 15) or Vt = 3 ml/kg (n = 15). Proinflammatory cytokines (interleukin‐6 (IL‐6), interleukin‐8 (IL‐8), and tumor necrosis factor (TNF)‐α) were determined in the tracheal aspirate on days 1, 3, and 7 of life. IL‐8 and TNF‐α levels collected on day 7 were significantly higher (P < 0.05), and mechanical ventilation lasted longer in the group with Vt = 3 ml/kg (16.8 ± 4 vs. 9.2 ± 4 days; P = 0.05). In conclusion, our data show significantly higher lung inflammation in preterm infants ventilated with Vt = 3 ml/kg, suggesting a role for Vt = 5 ml/kg in reducing both inflammatory response during the acute phase of RDS and the length of ventilation. Whether the use of this starting Vt prevents bronchopulmonary dysplasia requires further study. Pediatr Pulmonol. © 2006 Wiley‐Liss, Inc.
Empirical potential function for simplified protein models: Combining contact and local sequence–structure descriptors
Authors: Zhang Jinfeng , Chen Rong , Liang Jie
Published: February 2006

An effective potential function is critical for protein structure prediction and folding simulation. Simplified protein models such as those requiring only Cα or backbone atoms are attractive because they enable efficient search of the conformational space. We show residue‐specific reduced discrete‐state models can represent the backbone conformations of proteins with small RMSD values. However, no potential functions exist that are designed for such simplified protein models. In this study, we develop optimal potential functions by combining contact interaction descriptors and local sequence–structure descriptors. The form of the potential function is a weighted linear sum of all descriptors, and the optimal weight coefficients are obtained through optimization using both native and decoy structures. The performance of the potential function in a test of discriminating native protein structures from decoys is evaluated using several benchmark decoy sets. Our potential function requiring only backbone atoms or Cα atoms have comparable or better performance than several residue‐based potential functions that require additional coordinates of side‐chain centers or coordinates of all side‐chain atoms. By reducing the residue alphabets down to size 10 for contact descriptors, the performance of the potential function can be further improved. Our results also suggest that local sequence–structure correlation may play important role in reducing the entropic cost of protein folding. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Evolutionary coupling of structural and functional sequence information in the intracellular lipid‐binding protein family
Authors: Marcelino Anna Marie C. , Smock Robert G. , Gierasch Lila M.
Published: February 2006

We have mined the evolutionary record for the large family of intracellular lipid‐binding proteins (iLBPs) by calculating the statistical coupling of residue variations in a multiple sequence alignment using methods developed by Ranganathan and coworkers (Lockless and Ranganathan, Science 1999:286;295–299). The 213 sequences analyzed have a wide range of ligand‐binding functions as well as highly divergent phylogenetic origins, assuring broad sampling of sequence space. Emerging from this analysis were two major clusters of coupled residues, which when mapped onto the structure of a representative iLBP under study in our laboratory, cellular retinoic‐acid binding protein I, are largely contiguous and provide useful points of comparison to available data for the folding of this protein. One cluster comprises a predominantly hydrophobic core away from the ligand‐binding site and likely represents key structural information for the iLBP fold. The other cluster includes the portal region where ligand enters its binding site, regions of the ligand‐binding cavity, and the region where the 10‐stranded β‐barrel characteristic of this family closes (between strands 1′ and 10). Linkages between these two clusters suggest that evolutionary pressures on this family constrain structural and functional sequence information in an interdependent fashion. The necessity of the structure to wrap around a hydrophobic ligand confounds the typical sequestration of hydrophobic side chains. Additionally, ligand entry and exit require these structures to have a capacity for specific conformational change during binding and release. We conclude that an essential and structurally apparent separation of local and global sequence information is conserved throughout the iLBP family. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Amino acid sequence predicts folding rate for middle‐size two‐state proteins
Authors: Huang Ji‐Tao , Tian Jing
Published: February 2006

The significant correlation between protein folding rates and the sequence‐predicted secondary structure suggests that folding rates are largely determined by the amino acid sequence. Here, we present a method for predicting the folding rates of proteins from sequences using the intrinsic properties of amino acids, which does not require any information on secondary structure prediction and structural topology. The contribution of residue to the folding rate is expressed by the residue's Ω value. For a given residue, its Ω depends on the amino acid properties (amino acid rigidity and dislike of amino acid for secondary structures). Our investigation achieves 82% correlation with folding rates determined experimentally for simple, two‐state proteins studied until the present, suggesting that the amino acid sequence of a protein is an important determinant of the protein‐folding rate and mechanism. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Upper susceptibility threshold limits with confidence intervals: a method to identify normal and abnormal population values for laboratory toxicological parameters, based on acetylcholinesterase activities in sea lice
Authors: Fallang Anders , Larsen Stig , Horsberg Tor E
Published: February 2006

The interpretation and importance of comparing field values of susceptibility to pesticides with a laboratory reference strain that might bear little resemblance to the actual situation in the field are problematic and a continuing subject of debate. In this paper a procedure for defining a ‘normal sensitive’ population from a field study of 383 individuals to provide a basis for analysing and interpreting in vitro results is described and examined. Instead of using only the 95th percentile, the upper and lower confidence limits for the 95th percentile were also compared to select the best estimation of the limit for the normal material. A field population constrained by the upper confidence limit for the 95th percentile provides appropriate descriptions of the normal material in this study. This approach should prove useful in studies of pesticide resistance in field populations. Copyright © 2006 Society of Chemical Industry
Impact of fungal drug transporters on fungicide sensitivity, multidrug resistance and virulence
Authors: de Waard Maarten A , Andrade Alan C , Hayashi Keisuke , Schoonbeek Henk‐jan , Stergiopoulos Ioannis , Zwiers Lute‐Harm
Published: February 2006

Drug transporters are membrane proteins that provide protection for organisms against natural toxic products and fungicides. In plant pathogens, drug transporters function in baseline sensitivity to fungicides, multidrug resistance (MDR) and virulence on host plants. This paper describes drug transporters of the filamentous fungi Aspergillus nidulans (Eidam) Winter, Botrytis cinerea Pers and Mycosphaerella graminicola (Fückel) Schroter that function in fungicide sensitivity and resistance. The fungi possess ATP‐binding cassette (ABC) drug transporters that mediate MDR to fungicides in laboratory mutants. Similar mutants are not pronounced in field resistance to most classes of fungicide but may play a role in resistance to azoles. MDR may also explain historical cases of resistance to aromatic hydrocarbon fungicides and dodine. In clinical situations, MDR development in Candida albicans (Robin) Berkhout mediated by ABC transporters in patients suffering from candidiasis is common after prolonged treatment with azoles. Factors that can explain this striking difference between agricultural and clinical situations are discussed. Attention is also paid to the risk of MDR development in plant pathogens in the future. Finally, the paper describes the impact of fungal drug transporters on drug discovery. Copyright © 2006 Society of Chemical Industry
Substituted α‐(phenylhydrazono)phenylacetonitrile derivatives. Part 1: A new class of uncoupler of oxidative phosphorylation
Authors: Danko Peter , Flury Thomas , Hall Roger G , Karrer Friedrich , Kienast Heinz , Kriz Miroslav , Leuenberger Katrin , Pascual Alfons , Steiger Arthur , Trah Stephan
Published: February 2006

Substituted α‐(phenylhydrazono)phenylacetonitrile derivatives have been discovered which constitute a series of potent uncouplers of oxidative phosphorylation. Systematic variation of substituents on both benzene rings has clearly demonstrated the importance of steric congestion around the ionisation site and delocalisation of negative charge in the anionic form. Replacement of the cyano group by other electron‐withdrawing groups leads to a dramatic decrease in uncoupling activity. The sub‐nanomolar levels of uncoupling activity found in certain members indicate that these compounds are the most potent uncouplers yet reported. Copyright © 2006 Society of Chemical Industry
Influence of Bacillus spp. isolated from maize agroecosystem on growth and aflatoxin B1 production by Aspergillus section Flavi
Authors: Bluma Romina V , Etcheverry Miriam G
Published: February 2006

A total of 59 bacteria of the Bacillus genus were isolated from different components of a maize agroecosystem and their antifungal activity against Aspergillus section Flavi was evaluated. Thirty‐three and 46% of these bacteria were able to inhibit Aspergillus flavus Link and A. parasiticus Speare respectively at water activity (aw) 0.982; however, when aw was 0.955, these percentages were decreased and only three isolates were able to inhibit Aspergillus section Flavi. The majority of bacilli acted as contact antagonists, while a small number of isolates were able to form inhibition zones. In maize meal extract agar, Aspergillus section Flavi growth rate and aflatoxin B1 (AFB1) production were significantly reduced when these strains were paired at aw 0.982 with bacilli at all inoculum levels studied. However, two bacilli isolated were able to reduce growth rate and aflatoxin production when aw was 0.955. Lag phase increase followed the same general pattern as growth rate reduction. When Aspergillus section Flavi was grown in sterile maize in the presence of three Bacillus strains at aw 0.982, the reduction in count (colony‐forming units (cfu) g−1 maize) was less than 30%, except when Aspergillus section Flavi grew with Bacillus amyloliquefaciens UNRCLR. However, levels of detectable AFB1 were significantly reduced in these interactions at aw 0.982. Copyright © 2006 Society of Chemical Industry
The use of an alternative food source (red clover) as a means of reducing slug pest damage to winter wheat: towards field implementation
Authors: Brooks Andrew S , Wilcox Andrew , Cook Richard T , James Katherine L , Crook Mitchell J
Published: February 2006

Slugs are major pests of many crops in the UK, including winter wheat, yet current methods of control are often unreliable. The aim of this study was to investigate three issues key to the successful field implementation of a control strategy that uses red clover as an alternative food source to reduce the amount of damage caused to winter wheat by the field slug, Deroceras reticulatum (Müller). A series of three experiments was designed to assess this aim. Firstly, under laboratory conditions, red clover was consumed in greater quantities than wheat, even when wheat was presented as a novel food. Secondly, red clover had no significant effects on the emergence and early growth of wheat in a polytunnel experiment. Both these results are crucial to the successful implementation of a strategy that uses red clover as an alternative food source. Lastly, the results of a field experiment were consistent with the results of the polytunnel experiment, in that red clover did not significantly affect wheat emergence. However, plots in which red clover was left to grow until the time of wheat harvest resulted in significantly lower (43%) wheat yields than plots without red clover. These results suggest that red clover must be removed from the field after the wheat has passed its vulnerable seedling stage. Recommendations for the potential use of red clover as an alternative food source for reducing damage to winter wheat in field conditions are discussed and opportunities for further work are suggested. Copyright © 2006 Society of Chemical Industry
Residues of diflubenzuron on horse chestnut (Aesculus hippocastanum) leaves and their efficacy against the horse chestnut leafminer, Cameraria ohridella
Authors: Nejmanová Jana , Cvačka Josef , Hrdý Ivan , Kuldová Jelena , Mertelík Josef , Muck Alexander , Nešněrová Petra , Svatoš Aleš
Published: February 2006

Residues of the insect growth regulator diflubenzuron were quantified on horse chestnut (Aesculus hippocastanum L.) leaves treated with a diflubenzuron 480 g litre−1 SC, Dimilin. To analyse the samples, an analytical procedure was developed involving a simple extraction step followed by high‐performance liquid chromatography on an octadecyl‐modified silica column with methanol + 0.01 M ammonium acetate mobile phase. The results showed diflubenzuron to be highly stable on horse chestnut leaves; more than 4 months (127 days) after application, 38% (on average) of the insecticide still remained on/in the leaves. The data confirmed biological observations showing diflubenzuron's long‐term efficacy against the horse chestnut leafminer, Cameraria ohridella Deschka & Dimić, which is the most important pest of the horse chestnut in Europe. The hypothesis of possible penetration of diflubenzuron into the leaf mass is explored and discussed. Copyright © 2006 Society of Chemical Industry
Substituted α‐(phenylhydrazono)phenylacetonitrile derivatives. Part 2: synthesis and biological activity of pro‐pesticides
Authors: Flury Thomas , Hall Roger G , Karrer Friedrich , Kienast Heinz , Leuenberger Katrin , Pascual Alfons , Rindlisbacher Alfred , Trah Stephan , Widmer Hans‐Joerg
Published: February 2006

Pro‐pesticides of α‐(2,6‐dichloro‐4‐trifluoromethylphenylhydrazono)‐4‐nitrophenylacetonitrile have been prepared and tested against mite and insect pests. Variations in potency and spectrum were observed depending on the choice of cleavable pro‐moiety. Cleavage of the pro‐moiety was demonstrated in one case by measuring the rate of increase in the uncoupling activity using a mitochondrial preparation. Irradiation experiments have demonstrated a rapid isomerisation of the planar Z isomer to the E isomer, which is reversible. Copyright © 2006 Society of Chemical Industry
Fitness costs of laboratory‐selected imidacloprid resistance in the brown planthopper, Nilaparvata lugens Stål
Authors: Liu Zewen , Han Zhaojun
Published: February 2006

Imidacloprid has been used as a key insecticide to control the brown planthopper, Nilaparvata lugens Stål, for several years, but no obvious resistance has been identified in field populations as yet. To evaluate the risk, a field population was collected and selected with imidacloprid in the laboratory. After 37‐generation selection a strain with 250‐fold resistance had been successfully achieved. Fitness analysis by constructing life tables demonstrated that resistant hoppers had obvious disadvantages in their reproduction. The fitness of highly resistant hoppers had decreased dramatically (0.169 and 0.104) to only one‐fifth to one‐tenth of that of the susceptible strain. Hence it was concluded that the brown planthopper had the potential to develop high resistance to imidacloprid but that the lower fitness of resistant hoppers could result in a quick recovery of sensitivity when the population did not come into contact with imidacloprid. This means that a reasonable resistance management programme with less imidacloprid use may efficiently delay or even stop resistance development. Copyright © 2006 Society of Chemical Industry
A system dynamics analysis of boom and bust in the shrimp aquaculture industry
Authors: Arquitt Steve , Honggang Xu , Johnstone Ron
Published: February 2006

Driven by growing international demand for shrimp and stagnating catches of wild shrimp, the shrimp aquaculture industry has grown remarkably over the past two decades. Initial hopes that farmed shrimp could provide an environmentally benign alternative to over‐exploited wild stocks have, however, proven disappointing. Although global growth has been steady, the industry has experienced dramatic production crashes at national and sub‐national scales associated with severe environmental damage. From a systems perspective, the industry is prone to exceed and consume its environmental carrying capacity, resulting in boom and bust patterns of development. In this paper we describe a dynamic commodity system model built to examine boom and bust in the shrimp aquaculture industry. Experiments with the model suggest that a policy that taxes the industry and rebates proceeds to licensed producers may help shift the system toward sustainability. Copyright © 2005 John Wiley & Sons, Ltd.
XMILE: towards an XML interchange language for system dynamics models
Authors: Diker Vedat G. , Allen Robert B.
Published: February 2006

We propose that XML should be used as an interchange language for system dynamics models and we have designed and implemented a demonstration that we call XMILE. We believe that there will be many benefits for the system dynamics community in developing a full‐scale interchange language. This paper discusses the motivation factors behind the idea of developing an interchange language for system dynamics models, and explains why XML is a good candidate framework. An initial implementation of XMILE is also presented along with initial findings about its applicability to models built on various system dynamics software platforms. Copyright © 2005 John Wiley & Sons, Ltd.
Statistical screening of system dynamics models
Authors: Ford Andrew , Flynn Hilary
Published: February 2006

This paper describes a pragmatic method of searching for the key inputs to a system dynamics model. This analysis is known as screening. The goal is to learn which of the many uncertain inputs stand out as most influential. The method is implemented with readily available software and relies on the simple correlation coefficient to indicate the relative importance of model inputs at different times in the simulation. The screening is demonstrated with two examples with step‐by‐step instructions. The paper recommends that screening analysis be used in an iterative process of screening and model expansion to arrive at tolerance intervals on model results. The appendices compare screening analysis with analytical methods to identify the key inputs to system dynamics models. Copyright © 2005 John Wiley & Sons, Ltd.
Improving strategic management with the fundamental principles of system dynamics
Authors: Warren Kim
Published: February 2006

A system dynamics perspective has a powerful logic that offers substantial improvements in dealing with issues in strategic management, whether one‐off challenges or the continuous direction of enterprise strategy. First, successful strategic management of business and non‐commercial organisations requires attention to how performance is changing through time. Since performance reflects the state of resources in any period, steering strategy requires policies and decisions that control the flow rates of those resources. Lastly, this is complicated by the additional dependence of these resource flows on the current state of existing and potential resources at each point in time—a dependence that gives rise to feedback. These principles can be organised into a rigorous approach to strategy that is grounded in solid evidence from the situation of concern. Important implications from this perspective include the unavoidable causal ambiguity caused by accumulating resources, and the value of explicit and quantitative examination of resource development prior to investigating feedback structures. Copyright © 2005 John Wiley & Sons, Ltd.
Shape optimization problems for eigenvalues of elliptic operators
Authors: Belhachmi Z. , Bucur D. , Buttazzo G. , Sac‐Epée J.‐M.
Published: February 2006

We consider a general formulation for shape optimization problems involving the eigenvalues of the Laplace operator. Both the cases of Dirichlet and Neumann conditions on the free boundary are studied. We survey the most recent results concerning the existence of optimal domains, and list some conjectures and open problems. Some open problems are supported by efficient numerical computations.
The Social Ecological Model and Physical Activity in African American Women
Authors: Fleury Julie , Lee Sarah M.
Published: February 2006

Little is known about the social and contextual correlates (e.g., social norms, environment, social networks, and organizational support) influencing the adoption and maintenance of regular physical activity among minority and underserved populations. The purpose of this review was to apply the social ecological model to better understand physical activity among African American women. A review of the literature pertaining to correlates of physical activity among African American women was conducted and applied to a social ecological perspective. Understanding and addressing social and contextual correlates of physical activity behavior among African American women are necessary to establish comprehensive programs, particularly within community settings. The social ecological model provides a strong theoretical basis to guide physical activity intervention in this population.
Development of gullies on the landscape: A model of headcut retreat resulting from plunge pool erosion
Authors: Flores‐Cervantes Javier H. , Istanbulluoglu Erkan , Bras Rafael L.
Published: February 2006

Head advance due to plunge pool erosion is a common process in gullies incising resistant soils. A model of headcut retreat resulting from plunge pool erosion is developed and implemented in the channel‐hillslope integrated landscape development (CHILD) model, an existing three‐dimensional landscape evolution modeling framework. The model estimates horizontal headcut retreat as a function of discharge, height of the headcut, upstream slope, and relevant land surface and soil properties for soil erosion. We analyze the sensitivity of headcut retreat to flow discharge, upstream slope and surface roughness, and headcut height. CHILD simulations indicate that headcut retreat is most significant in zones with either gentle slopes or large headcut heights. Model parameters have contrasting effects on the retreat rates depending on the size and depth of the pool beneath the headcut and upstream flow hydraulics, making the process difficult to predict as a function of topographic thresholds and simple geomorphic transport laws.
Monsoon onset over Sudan‐Sahel: Simulation by the regional scale model MM5
Authors: Sijikumar S. , Roucou Pascal , Fontaine Bernard
Published: February 2006

The Mesoscale Model MM5 is used to study the regional features of the West African Monsoon onset. In order to increase the results, simulations are carried out for eight consecutive seasons (March to September) of the years 1994 to 2001. The results show that the model can reproduce the dynamical features of the monsoon in a reasonably good manner but the seasonal cycle seems enhanced. It is hypothesized that overestimated rainfall amounts could be related to a poor representation of the land surface characteristics. Nevertheless, the mean simulated monsoon onset dates are similar to those find in the CMAP data set. The onset is characterized by an apparent increase in zonal flow that could bring moisture from the eastern Atlantic ocean, in conjunction with a deepening of the Saharan heat low. These results show that the model can be used to detail the basic processes linked to the monsoon onset and to perform dynamical downscaling.
Hysteresis in solar wind power input to the magnetosphere
Authors: Palmroth Minna , Janhunen Pekka , Pulkkinen Tuija I.
Published: February 2006

We examine the clock angle dependence of the solar wind power input into the magnetosphere using the Grand Unified Magnetosphere Ionosphere Coupling Simulation (GUMICS‐4). We compute the power input through the magnetopause systematically in four events where the solar wind parameters are otherwise kept constant, but the interplanetary magnetic field (IMF) clock angle θ is rotated from 0° to 360°. We find that when the clock angle rotates from north to south, the power input is well represented by sin2(θ/2). However, during the return rotation from south to north, the power input in the simulation remains enhanced longer than a sin2(θ/2) dependence would indicate. We suggest that the enhanced energy input during the return rotation may be a consequence of the nature of the reconnection process at the magnetopause.
Rotational stability of dynamic planets with elastic lithospheres
Authors: Matsuyama I. , Mitrovica J. X. , Manga M. , Perron J. T. , Richards M. A.
Published: February 2006

We revisit the classic problem of the secular rotational stability of planets in response to loading using the fluid limit of viscoelastic Love number theory. Gold (1955) and Goldreich and Toomre (1969) considered the stability of a hydrostatic planet subject to an uncompensated surface mass load and concluded that a mass of any size would drive true polar wander (TPW) that ultimately reorients the load to the equator. Willemann (1984) treated the more self‐consistent problem where the presence of a lithosphere leads to both imperfect load compensation and a remnant rotational bulge. Willemann considered axisymmetric loads and concluded that the equilibrium pole location was governed by a balance, independent of elastic lithospheric thickness, between the load‐induced TPW and stabilization by the remnant bulge. Our new analysis demonstrates that the equilibrium pole position is a function of the lithospheric strength, with a convergence to Willemann's results evident at high values of elastic thickness (>400 km for an application to Mars), and significantly larger predicted TPW for planets with thin lithospheres. Furthermore, we demonstrate that nonaxisymmetric surface mass loads and internal (convective) heterogeneity, even when these are small relative to axisymmetric contributions, can profoundly influence the rotational stability. Indeed, we derive the relatively permissive conditions under which nonaxisymmetric forcing initiates an inertial interchange TPW event (i.e., a 90° pole shift). Finally, Willemann's analysis is often cited to argue for a small (<18°) TPW of Mars driven by the development of a Tharsis‐sized load. We show that even in the absence of the destabilizing effects of load asymmetry, the equations governing rotational stability permit higher excursions of the Martian rotation vector than has previously been appreciated.
Climatic changes in the northern Red Sea during the last 22,000 years as recorded by calcareous nannofossils
Authors: Legge Heiko Lars , Mutterlose Jörg , Arz Helge W.
Published: February 2006

We present a high‐resolution record of calcareous nannofossils from the northern Red Sea for the last 22 kyr. Extreme conditions with enhanced salinities during the Last Glacial Maximum are characterized by high values ofGephyrocapsa ericsonii. The dominance ofEmiliania huxleyiin Heinrich event 1 indicates a climatic cooling favoring the bloom of opportunistic species. The calcareous nannofossils record a two‐step onset of the postglacial humid climate, punctuated by the Younger Dryas. Both steps show an early oligotrophic phase dominated byFlorisphaera profundaandGladiolithus flabellatusand a subsequent fertile phase characterized byE. huxleyi. The Younger Dryas is described by high values ofGephyrocapsa oceanica, indicating an increased mixing of the water column. In the late Holocene, repetitive increases in abundance ofF. profundaandG. flabellatusreflect restricted oligotrophic conditions, caused by the high aridity following the Holocene humid period.
Seasonal patterns of alkenone production in the subtropical oligotrophic North Pacific
Authors: Popp Brian N. , Prahl Fredrick G. , Wallsgrove Richard J. , Tanimoto Jamie
Published: February 2006

Seasonal alkenone concentrations, production rates, and unsaturation patterns (U37K′) were measured at station ALOHA in the oligotrophic subtropical North Pacific. Highest alkenone concentration and production rates were found in (winter and fall) or just below (summer) the surface mixed layer. Lowest alkenone concentration and production rates were found within the deep chlorophyll maximum layer (DCML). In the DCML, which occurs at 80–120 m throughout the year, U37K′temperatures overestimated water temperatures by ∼2°–4°C. This result probably reflected the effect of light limitation on the physiology of alkenone‐producing algae. At the depth of maximum alkenone production, U37K′temperatures underestimated water temperature by ∼2°–4°C in summer and fall but overestimated in situ temperatures by ∼1°–2°C in winter. The underestimate of measured water temperature in summer and fall most likely reflected a physiological response to limited nutrient availability. The U37K′temperature overestimate in winter was best explained by a change in the ecology of alkenone‐producing algae.
Nonmonotonic trajectories to a partially penetrating well in a semiconfined aquifer
Authors: Bruggeman G. A. , Veling E. J. M.
Published: February 2006

The flow path to a partially penetrating well in a semiconfined aquifer with finite thickness can exhibit nonmonotonic behavior. Water particles entering a semiconfined aquifer far away from a well through the confining layer go downward, and closer to the well they move upward, while under certain circumstances they rise so high that they come down again to finally be captured by the well. An approximative problem is solved analytically under the assumptions that the aquifer is of infinite thickness and that the screen may be represented as a point. It is shown that this phenomenon will occur for particular values of parameters Kc/a > 1.283, where a is the position of the point extraction in the aquifer with respect to the top of the aquifer, K is the hydraulic conductivity of the aquifer, and c is the hydraulic resistance of the covering layer. Such upward bending groundwater path lines have ecological implications in the sense that water from far away will come close to the top of the aquifer in the neighborhood of the well.