bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling evapotranspiration in Arctic coastal plain ecosystems using a modified BIOME‐BGC model
Authors: Engstrom Ryan , Hope Allen , Kwon Hyojung , Harazono Yoshinobu , Mano Masayoshi , Oechel Walter
Published: June 2006

Modeling evapotranspiration (ET) in Arctic coastal plain ecosystems is challenging owing to the unique conditions present in this environment, including permafrost, nonvascular vegetation, and a large standing dead vegetation component. In this study the ecosystem process model, BIOME‐BGC, was adapted to represent these unique conditions in Arctic ecosystems by including a new water storage and evaporation routine that accounts for nonvascular vegetation and the effects of permafrost, adding ground heat flux as an input, and representing ground shading by dead vegetation. The new Arctic version and the original BIOME‐BGC models are compared to observed ET from two eddy flux towers in Barrow, Alaska over four summer seasons (1999–2002). The two towers are located less than 1 km apart, yet represent contrasting moisture conditions. One is located in a drained thaw lake, marsh area, while the other is located in a drier, upland area characterized by mesic tundra. Results indicate that the original BIOME‐BGC model substantially underestimated ET, while the Arctic version slightly overestimated ET at both sites. The new Arctic model version worked particularly well at the wet tower because the model was able to capture energy limitations better than water limitations. Errors in the simulation of snowmelt date led to errors in the ET estimates at both sites. Finally, the substantial differences in soil moisture led to substantially different ET rates between the sites that were difficult to simulate and indicates that soil moisture heterogeneity is a strong controller on ET in these ecosystems.
Bayesian detection of radar interference in radio astronomy
Authors: Jeffs Brian D. , Lazarte Weizhen , Fisher J. Richard
Published: June 2006

L‐Band observations at the Green Bank Telescope (GBT) and other radio observatories are often made in frequency bands allocated to aviation pulsed radar transmissions. It is possible to mitigate radar contamination of the astronomical signal by time blanking data containing these pulses. However, even when strong direct path pulses and nearby fixed clutter echoes are removed there are still undetected weaker aircraft echoes present which can corrupt the data. In a previous paper we presented an algorithm to improve real‐time echo blanking by forming a Kalman filter tracker to follow the path of a sequence of echoes observed on successive radar antenna sweeps. The tracker builds a history which can be used to predict the location of upcoming echoes. We now present details of a new Bayesian detection algorithm which uses this prediction information to enable more sensitive weak pulse acquisition. The developed track information is used to form a spatial prior probability distribution for the presence of the next echoes. Regions with higher probability are processed with a lower detection threshold to pull out low level pulses without increasing the overall probability of false alarm detection. The ultimate result is more complete removal, by blanking the detected pulse, of radar corruption in astronomical observations.
Kinematic wave model of bed profiles in alluvial channels
Authors: Tayfur Gokmen , Singh Vijay P.
Published: June 2006

A mathematical model, based on the kinematic wave (KW) theory, is developed for describing the evolution and movement of bed profiles in alluvial channels. The model employs a functional relation between sediment transport rate and concentration, a relation between flow velocity and depth and Velikanov's formula relating suspended sediment concentration to flow variables. Laboratory flume and field data are used to test the model. Transient bed profiles in alluvial channels are also simulated for several hypothetical cases involving different water flow and sediment concentration characteristics. The model‐simulated bed profiles are found to be in good agreement with what is observed in the laboratory, and they seem theoretically reasonable for hypothetical cases. The model results reveal that the mean particle velocity and maximum concentration (maximum bed form elevation) strongly affect transient bed profiles.
An intrinsically shielded hydrogel for the adsorptive recovery of lysozyme
Authors: Wang Lu , Zhang Rongsheng , Eisenthal Robert , Hubble John
Published: June 2006

The present paper addresses the selective recovery of lysozyme from egg white using CM‐dextran (carboxymethyldextran)‐based hydrogels containing Cibacron Blue as an affinity ligand and co‐immobilized BSA intended to act as a shielding agent to reduce non‐specific adsorption. Initial studies using pure lysozyme were conducted that indicated that the adsorption capacity increased with ligand density and that adsorption was well described by a Langmuir‐type isotherm. The inclusion of BSA as a putative shielding agent did not decrease the adsorption capacity for lysozyme in single‐adsorbate experiments. To assess the effectiveness of the shielding strategy, subsequent experiments were conducted with both defined lysozyme/ovalbumin mixtures and hen's‐egg white. From these studies, the optimal operating conditions for lysozyme recovery have been determined. These include: optimal initial egg‐white concentration [a 10% (v/v) solution of native egg white in the chosen buffer], affinity‐ligand density (1.86 mM) and ligand‐to‐shielding‐agent ratio (4:1). The purity of lysozyme obtained from egg white was improved from 69% with a non‐shielded hydrogel to 94% with an intrinsically shielded hydrogel. Finally, the possibility of using a protein, rather than dextran‐backbone‐based, hydrogel was investigated. It was found that BSA could take the place of CM‐dextran as the gel backbone in a simplified synthesis, producing a gel which also proved effective for lysozyme recovery with a 30% lysozyme in egg‐white solution purified to approx. 92% in a single adsorption–desorption cycle.
Effects of mediators on the laccase biosensor response in paracetamol detection
Authors: Odaci Dilek , Timur Suna , Pazarlioğlu Nurdan , Kirgöz Ülkü Anik , Telefoncu Azmi
Published: June 2006

An enzyme electrode suitable for paracetamol detection was developed by immobilizing laccase on a dissolved‐oxygen probe surface. The immobilization procedure was achieved by means of gelatin, which was then cross‐linked with glutaraldehyde. The measurement was based on the detection of oxygen consumption in relation to analyte oxidation. The optimum experimental conditions for the biosensor were investigated and the system was calibrated for paracetamol. Also the effects of three different mediators, namely HBT (1‐hydroxybenzotriazole), VLA [violuric acid (5‐isonitrosobarbituric acid)] and TEMPO (2,2′,6,6′‐tetramethylpiperidine‐N‐oxyl radical) were tested for the biosensor's response. As a result, it was observed that HBT has a remarkable effect on the signal by providing more oxygen consumption during the enzymatic reaction. A linear relationship between sensor responses and analyte concentrations was obtained over the concentration range 2.0–15.0 μM, whereas, in the presence of the mediator HBT, this range became 0.5–3.0 μM.
Vibrational shifts of OCS in mixed clusters of parahydrogen and helium
Authors: Paesani F. , Whaley K. B.
Published: June 2006

We present a detailed theoretical study of the solvation structure and solvent induced vibrational shifts for an OCS molecule embedded in pure parahydrogen clusters and in mixed parahydrogen/helium clusters. The use of two recent OCS-(parahydrogen) and OCS-helium ab initio potential energy surfaces having explicit dependence on the asymmetric stretch of the OCS molecule allows calculation of the frequency shift of the OCS ν3 vibration as a function of the cluster size and composition. We present results for clusters containing up to a full first solvation shell of parahydrogen (N=17molecules), and up to M=128−N helium atoms. Due to the greater interaction strength of parahydrogen than helium with OCS, in the mixed clusters the parahydrogen molecules always displace He atoms in the first solvation shell around OCS and form multiple axial rings as in the pure parahydrogen clusters. In the pure clusters, the chemical potential of parahydrogen shows several magic numbers (N=8,11,14) that reflect an enhanced stability of axial rings containing one less molecule than required for complete filling at N=17. Only the N=14 magic number survives in the mixed clusters, as a result of different filling orders of the rings and greater delocalization of both components. The OCS vibration shows a redshift in both pure and mixed clusters, with N-dependent values that are in good agreement with the available experimental data. The dependence of the frequency shift on the cluster size and its composition is analyzed in terms of the parahydrogen and helium density distributions around the OCS molecule as a function of N and M. The frequency shift is found to be strongly dependent on the detailed distribution of the parahydrogen molecules in the pure parahydrogen clusters, and to be larger but show a smoother dependence on N in the presence of additional helium, consistent with the more delocalized nature of the mixed clusters.
On the geometry of Killing and conformal tensors
Authors: Coll Bartolomé , Ferrando Joan Josep , Sáez Juan Antonio
Published: June 2006

The second order Killing and conformal tensors are analyzed in terms of their spectral decomposition, and some properties of the eigenvalues and the eigenspaces are shown. When the tensor is of type I with only two different eigenvalues, the condition to be a Killing or a conformal tensor is characterized in terms of its underlying almost-product structure. A canonical expression for the metrics admitting these kinds of symmetries is also presented. The space–time cases 1+3 and 2+2 are analyzed in more detail. Starting from this approach to Killing and conformal tensors a geometric interpretation of some results on quadratic first integrals of the geodesic equation in vacuum Petrov-Bel type D solutions is offered. A generalization of these results to a wider family of type D space–times is also obtained.
Terahertz magneto-optic generalized ellipsometry using synchrotron and blackbody radiation
Authors: Hofmann T. , Schade U. , Herzinger C. M. , Esquinazi P. , Schubert M.
Published: June 2006

We report on the first setup and experimental verification of terahertz frequency domain magneto-optic generalized ellipsometry using a combination of highly brilliant terahertz synchrotron and conventional blackbody radiation sources. The polarizer-sample-rotating-analyzer ellipsometry principle is employed to measure the three normalized Stokes vector elements excluding depolarization information, and the upper left 3×3 block of the normalized 4×4 Mueller matrix accordingly for wave numbers from 30to650cm−1 (0.9–20THz). We discuss setup, measurement, and data analysis procedures specific to the use of synchrotron radiation for terahertz ellipsometry. Two sample systems with different free-charge-carrier properties were studied and are presented here to illustrate terahertz ellipsometry and data analysis. The first example is low-chlorine-doped ZnMnSe, a dilute magnetic semiconductor. Analysis of the normalized Mueller matrix elements using the Drude magneto-optic dielectric function tensor model over the entire spectral range from 30to650cm−1 allowed the independent determination of the free-charge-carrier properties effective mass, concentration, and mobility. We further present and discuss Mueller matrix spectra obtained from highly oriented pyrolytic graphite at low temperatures. The spectra of this second example, a two-dimensionally confined charge carrier system, reveal distinct fingerprints of chiral electronic transitions between Landau levels.
Electro-optical sampling at near-zero optical bias
Authors: Li Yuelin
Published: June 2006

We report a detailed study of distortion effects in electro-optical sampling measurement at near-zero optical bias. It is found that when the induced optical retardation has a dynamic range larger than the optical bias, a false polarity change of the field can be observed merely due to the amplitude change of the field under investigation. The distortion cannot be corrected in general. However, when the optical bias is known, this phenomenon can be exploited to derive the absolute field amplitude under study.
Magnetic and magnetotransport properties of La0.7Sr0.3MnO3/Permalloy heterostructures
Authors: Ruotolo A. , Oropallo A. , Miletto Granozio F. , Pepe G. P. , Perna P. , Scotti di Uccio U.
Published: June 2006

The magnetic and magnetotransport properties of La0.7Sr0.3MnO3/Permalloy heterostructures are investigated. La0.7Sr0.3MnO3 films were grown on (110) SrTiO3 in order to induce an in-plane anisotropy with the easy axis along the [001] direction. An easy axis of magnetization was induced in the Permalloy in the same direction through the application of a magnetic field during the growth. The magnetic characterization of the bilayer is presented and discussed. The transport properties of devices operated in the current perpendicular to plane mode are shown. The possibility of fabricating magnetoresistive devices by simply depositing a ferromagnetic counterelectrode on a manganite film is demonstrated.
Association of plasma metabolites and hormones with the growth and composition of lambs as affected by nutrition and sire genetics
Authors: Hegarty R. S. , McFarlane J. R. , Banks R. , Harden S.
Published: June 2006

An experiment was conducted to test 3 hypotheses regarding the variation in plasma parameters and their association with lamb growth and composition. The experiment tested whether sire genetics and available nutrition affected specific plasma traits, whether these traits were associated with growth and compositional characteristics, and whether data on plasma traits could improve the prediction of growth and carcass composition. Lambs (n = 103) produced by sires differing in estimated breeding values for growth, muscling, and fat were reared on LOW or HIGH planes of lifetime nutrition. Blood samples were collected immediately prior to weaning and before slaughter at 8 months of age. Concentrations of plasma creatinine (CRE), urea (PUN), insulin like growth factor I (IGF-I) were measured in all samples. Leptin was measured in samples from male lambs only (n = 56). HIGH nutrition increased preweaning and preslaughter IGF-I and leptin concentrations; nutritional effects on PUN and CRE were inconsistent. Lambs of the high muscle sire-type exhibited increased plasma IGF-I, reduced PUN, and an increased PUN : CRE ratio preweaning. Increased genetic potential of the sire for growth reduced PUN and increased PUN : CRE ratio. Plasma IGF-I correlated strongly with lamb growth rate (r2 = 0.49). Interaction of nutrition and sire-type for preslaughter leptin mimicked the interaction occurring for carcass fat, providing an example of selection on genotype inducing a physiological (hormonal) change and resulting in a modified phenotype.
Stepwise regressions developed to predict carcass protein and fat mass from information available at weaning or at slaughter indicated that inclusion of plasma parameters in these models caused only small increases in the proportion of variance accounted for. The most significant benefit was an increase in the proportion of variance in carcass weight accounted for (from 65 to 73%) by including IGF-I and CRE as predictors compared with prediction from weaning weight alone. If slaughter data were available, then >90% of the variance in carcass fat and protein masses was explained by carcass weight alone and this was not increased by inclusion of any preslaughter plasma parameter in the model. It was concluded that while nutrition and the genetic capacity of the sire (especially for muscling) affect plasma constituents as well as lamb growth and carcass composition, the inclusion of the measured plasma traits in models to predict final carcass composition from weaning data or slaughter data is unlikely to improve the prediction sufficient to justify the additional measurement cost.
Effect of nutritional restriction and sire genotype on forelimb bone growth and carcass composition in crossbred lambs
Authors: Cake M. A. , Gardner G. E. , Hegarty R. S. , Boyce M. D. , Pethick D. W.
Published: June 2006

The aim of this study was to assess the effect of low or high whole-of-life nutritional planes on bone growth, maturation, and carcass composition in lambs from sires (n = 9) with high estimated breeding values (EBVs) for post-weaning eye muscle depth (PEMD) or liveweight gain (PWWT), compared with sires of industry average for both traits. Lambs (n = 54) were killed at 8 months of age before measurement of forelimb bones, radiographic scoring, and histological measurement of growth plates, and bone ash mineral analysis. A subset of these (n = 36) had carcass composition serially assessed during growth by CAT-scan. Results reveal that the nutritional restriction imposed in this experiment caused significant restriction of skeletal growth, as reflected by shorter, thinner forelimb bones, altered limb proportions, narrowing (and in some cases permanent closure) of growth plates, and an altered bone mineral profile. CAT-scan analysis showed restriction of bone growth was similar to that of muscle growth. Progeny of high muscling (PEMD) sires showed greater muscle growth, but were possibly more susceptible to some of the skeletal effects of nutritional restriction. Greater sire EBVs for PEMD, PWWT, or fat depth were associated with narrower growth plates, suggestive of slower longitudinal bone growth and shorter adult limb length, although bone mass was not affected according to earlier CAT-scan data. Results also suggest that progeny of high PEMD or PWWT sires are earlier maturing in terms of skeletal (or at least limb) growth, although their bone mineral profile (magnesium content) was more consistent with that of physiologically less mature animals.
Linking DNA-binding proteins to their recognition sequences by using protein microarrays
Authors: Ho Su-Wen , Jona Ghil , Chen Christina T. L. , Johnston Mark , Snyder Michael
Published: June 2006

Analyses of whole-genome sequences and experimental data sets have revealed a large number of DNA sequence motifs that are conserved in many species and may be functional. However, methods of sufficient scale to explore the roles of these elements are lacking. We describe the use of protein arrays to identify proteins that bind to DNA sequences of interest. A microarray of 282 known and potential yeast transcription factors was produced and probed with oligonucleotides of evolutionarily conserved sequences that are potentially functional. Transcription factors that bound to specific DNA sequences were identified. One previously uncharacterized DNA-binding protein, Yjl103, was characterized in detail. We defined the binding site for this protein and identified a number of its target genes, many of which are involved in stress response and oxidative phosphorylation. Protein microarrays offer a high-throughput method for determining DNA–protein interactions.
Modeling the Lac repressor-operator assembly: The influence of DNA looping on Lac repressor conformation
Authors: Swigon David , Coleman Bernard D. , Olson Wilma K.
Published: June 2006

Repression of transcription of the
Escherichia coli
Lac operon by the Lac repressor (LacR) is accompanied by the simultaneous binding of LacR to two operators and the formation of a DNA loop. A recently developed theory of sequence-dependent DNA elasticity enables one to relate the fine structure of the LacR–DNA complex to a wide range of heretofore-unconnected experimental observations. Here, that theory is used to calculate the configuration and free energy of the DNA loop as a function of its length and base-pair sequence, its linking number, and the end conditions imposed by the LacR tetramer. The tetramer can assume two types of conformations. Whereas a rigid V-shaped structure is observed in the crystal, EM images show extended forms in which two dimer subunits are flexibly joined. Upon comparing our computed loop configurations with published experimental observations of permanganate sensitivities, DNase I cutting patterns, and loop stabilities, we conclude that linear DNA segments of short-to-medium chain length (50–180 bp) give rise to loops with the extended form of LacR and that loops formed within negatively supercoiled plasmids induce the V-shaped structure.
The cell surface leucine-rich repeat receptor for
At
Pep1, an endogenous peptide elicitor in
Arabidopsis
, is functional in transgenic tobacco cells
Authors: Yamaguchi Yube , Pearce Gregory , Ryan Clarence A.
Published: June 2006

At
Pep1 is a 23-aa endogenous peptide elicitor from
Arabidopsis
leaves that signals the activation of components of the innate immune response against pathogens. Here, we report the isolation of an
At
Pep1 receptor from the surface of
Arabidopsis
suspension-cultured cells. An
125
I-labeled
At
Pep1 analog interacted with suspension-cultured
Arabidopsis
with a
K
d
of 0.25 nM, and an
125
I-labeled azido-Cys-
At
Pep1 photoaffinity analog specifically labeled a membrane-associated protein of ≈170 kDa. The labeled protein was purified to homogeneity, and its tryptic peptides were identified as gene At1g73080, which encodes a leucine-rich repeat receptor kinase, here called PEPR1. Verification of the binding protein as the receptor for
At
Pep1 was established by demonstrating the loss of function of microsomal membranes of two SALK insertional mutants and by a gain in function of the alkalinization response to
At
Pep1 by tobacco suspension-cultured cells expressing the At1g73080 transgene. Synthetic homologs of
At
Pep1, deduced from the C termini of six known paralogs of
PROPEP1
, were biologically active and were competitors of the interaction of an
At
Pep1 radiolabeled analog with the receptor. The data are consistent with a role for PEPR1 as the receptor for
At
Pep1 to amplify innate immunity in response to pathogen attacks.
Phosphoproteomic analysis of Her2/neu signaling and inhibition
Authors: Bose Ron , Molina Henrik , Patterson A. Scott , Bitok John K. , Periaswamy Balamurugan , Bader Joel S. , Pandey Akhilesh , Cole Philip A.
Published: June 2006

Her2/neu (Her2) is a tyrosine kinase belonging to the EGF receptor (EGFR)/ErbB family and is overexpressed in 20–30% of human breast cancers. We sought to characterize Her2 signal transduction pathways further by using MS-based quantitative proteomics. Stably transfected cell lines overexpressing Her2 or empty vector were generated, and the effect of an EGFR and Her2 selective tyrosine kinase inhibitor, PD168393, on these cells was characterized. Quantitative measurements were obtained on 462 proteins by using the SILAC (stable isotope labeling with amino acids in cell culture) method to monitor three conditions simultaneously. Of these proteins, 198 showed a significant increase in tyrosine phosphorylation in Her2-overexpressing cells, and 81 showed a significant decrease in phosphorylation. Treatment of Her2-overexpressing cells with PD168393 showed rapid reversibility of the majority of the Her2-triggered phosphorylation events. Phosphoproteins that were identified included many known Her2 signaling molecules as well as known EGFR signaling proteins that had not been previously linked to Her2, such as Stat1, Dok1, and δ-catenin. Importantly, several previously uncharacterized Her2 signaling proteins were identified, including Axl tyrosine kinase, the adaptor protein Fyb, and the calcium-binding protein Pdcd-6/Alg-2. We also identified a phosphorylation site in Her2, Y877, which is located in the activation loop of the kinase domain, is distinct from the known C-terminal tail autophosphorylation sites, and may have important implications for regulation of Her2 signaling. Network modeling, which combined phosphoproteomic results with literature-curated protein–protein interaction data, was used to suggest roles for some of the previously unidentified Her2 signaling proteins.
A loop network within the anthrax toxin pore positions the phenylalanine clamp in an active conformation
Authors: Melnyk Roman A. , Collier R. John
Published: June 2006

Heptameric pores formed in the endosomal membrane by the protective antigen moiety of anthrax toxin serve as portals for entry of the enzymatic moieties of the toxin into the cytosol. In the aqueous lumen of each pore is a “Phe clamp,” a heptad of narrowly apposed Phe residues (Phe-427), that catalyzes the unfolding and translocation of the enzymatic moieties across the membrane. Here, we provide evidence for a “loop swap” between neighboring protective antigen subunits, which is required for efficient translocation and is mediated by a salt bridge formed between the side chains of Lys-397 and Asp-426. We propose that the interaction between residues 397 and 426 creates a structural framework that positions Phe-427 within the pore lumen, forming a functional Phe clamp and, hence, a translocation-competent pore.
General practice in prisons in England: Views from the field
Authors: Marks Linda , Gray Andrew , Pearce Sarah
Published: June 2006

The standard of health care in prisons should be equivalent to that provided in the community. Prison populations are multiply disadvantaged and primary health care practitioners in prisons routinely face organisational and ethical challenges which are rare in community‐based general practice. This raises the question of whether doctors working in prisons consider they would benefit from additional clinical skills or training, the range of prison‐specific competencies they consider important and what they would like to see included in induction programmes. Through a series of semi‐structured, faceto‐face interviews with doctors and health care managers working in prisons, this study sought to
identify views on the training needs for doctors working in prisons. Practitioners demonstrated that induction processes were varied and fragmented and that delivering primary care in prisons raised additional clinical and organisational challenges. Relationships with prisoner patients were generally good. Few ethical issues were raised by this small sample, with the exception of confidentiality. However, aspirations towards equivalence were tempered by tensions between custodial needs and clinical requirements, and more research should be directed to the ways practitioners negotiate this interface. Induction programmes should ensure that all practitioners receive practical and ethical guidance to help them address these tensions.
Phosphoinositide-dependent kinase 1 targets protein kinase A in a pathway that regulates interleukin 4
Authors: Nirula Ajay , Ho Mary , Phee Hyewon , Roose Jeroen , Weiss Arthur
Published: June 2006

CD28 plays a critical role in T cell immune responses. Although the kinase Akt has been shown to act downstream of CD28 in T helper (Th)1 cytokine induction, it does not induce Th2 cytokines such as interleukin 4 (IL-4). We recently reported that phosphoinositide-dependent kinase 1 (PDK1) partially corrects the defect in IL-4 production present in CD28-deficient T cells, suggesting that PDK1 regulates IL-4 independently of Akt. We now describe a signaling pathway in which PDK1 targets IL-4 in the murine Th2 cell line D10. PDK1-mediated activation of this pathway is dependent on protein kinase A (PKA) and the nuclear factor of activated T cells (NFAT) P1 transcriptional element in the IL-4 promoter. PDK1 localizes to the immune synapse in a phosphatidylinositol 3-kinase–dependent manner, partially colocalizes with PKA at the synapse, and physically interacts with PKA. In RNA interference knockdown experiments, PDK1 is necessary for phosphorylation of PKA in T cells, as well as for activation of the IL-4 NFAT P1 element by the T cell receptor (TCR) and CD28. Phosphorylation of the critical PKA threonine residue is stimulated by engagement of TCR/CD28 via a PDK1-dependent mechanism. These findings together define a pathway linking the kinases PDK1 and PKA in the induction of the Th2 cytokine IL-4.
Critical roles of the immunoglobulin intronic enhancers in maintaining the sequential rearrangement of IgH and Igk loci
Authors: Inlay Matthew A. , Lin Tongxiang , Gao Heather H. , Xu Yang
Published: June 2006

V(D)J recombination of immunoglobulin (Ig) heavy (IgH) and light chain genes occurs sequentially in the pro– and pre–B cells. To identify cis-elements that dictate this order of rearrangement, we replaced the endogenous matrix attachment region/Igk intronic enhancer (MiEκ) with its heavy chain counterpart (Eμ) in mice. This replacement, denoted EμR, substantially increases the accessibility of both Vκ and Jκ loci to V(D)J recombinase in pro–B cells and induces Igk rearrangement in these cells. However, EμR does not support Igk rearrangement in pre–B cells. Similar to that in MiEκ−/− pre–B cells, the accessibility of Vκ segments to V(D)J recombinase is considerably reduced in EμR pre–B cells when compared with wild-type pre–B cells. Therefore, Eμ and MiEκ play developmental stage-specific roles in maintaining the sequential rearrangement of IgH and Igk loci by promoting the accessibility of V, D, and J loci to the V(D)J recombinase.
Splenectomy inactivates the cholinergic antiinflammatory pathway during lethal endotoxemia and polymicrobial sepsis
Authors: Huston Jared M. , Ochani Mahendar , Rosas-Ballina Mauricio , Liao Hong , Ochani Kanta , Pavlov Valentin A. , Gallowitsch-Puerta Margot , Ashok Mala , Czura Christopher J. , Foxwell Brian , Tracey Kevin J. , Ulloa Luis
Published: June 2006

The innate immune system protects against infection and tissue injury through the specialized organs of the reticuloendothelial system, including the lungs, liver, and spleen. The central nervous system regulates innate immune responses via the vagus nerve, a mechanism termed the cholinergic antiinflammatory pathway. Vagus nerve stimulation inhibits proinflammatory cytokine production by signaling through the α7 nicotinic acetylcholine receptor subunit. Previously, the functional relationship between the cholinergic antiinflammatory pathway and the reticuloendothelial system was unknown. Here we show that vagus nerve stimulation fails to inhibit tumor necrosis factor (TNF) production in splenectomized animals during lethal endotoxemia. Selective lesioning of the common celiac nerve abolishes TNF suppression by vagus nerve stimulation, suggesting that the cholinergic pathway is functionally hard wired to the spleen via this branch of the vagus nerve. Administration of nicotine, an α7 agonist that mimics vagus nerve stimulation, increases proinflammatory cytokine production and lethality from polymicrobial sepsis in splenectomized mice, indicating that the spleen is critical to the protective response of the cholinergic pathway. These results reveal a specific, physiological connection between the nervous and innate immune systems that may be exploited through either electrical vagus nerve stimulation or administration of α7 agonists to inhibit proinflammatory cytokine production during infection and tissue injury.
Plasmacytoid dendritic cells of melanoma patients present exogenous proteins to CD4+ T cells after FcγRII-mediated uptake
Authors: Benitez-Ribas Daniel , Adema Gosse J. , Winkels Gregor , Klasen Ina S. , Punt Cornelis J.A. , Figdor Carl G. , de Vries I. Jolanda M.
Published: June 2006

Plasmacytoid dendritic cells (pDCs) contribute to innate antiviral immune responses by producing type I interferons. Although human pDCs can induce T cell responses upon viral infection, it remains unclear if pDCs can present exogenous antigens. Here, we show that human pDCs exploit FcγRII (CD32) to internalize antigen–antibody complexes, resulting in the presentation of exogenous antigen to T cells. pDCs isolated from melanoma patients vaccinated with autologous monocyte-derived peptide- and keyhold limpet hemocyanin (KLH)–loaded dendritic cells, but not from nonvaccinated patients or patients that lack a humoral response against KLH, were able to stimulate KLH-specific T cell proliferation. Interestingly, we observed that internalization of KLH by pDCs depended on the presence of serum from vaccinated patients that developed an anti-KLH antibody response. Anti-CD32 antibodies inhibited antigen uptake and presentation, demonstrating that circulating anti-KLH antibodies binding to CD32 mediate KLH internalization. We conclude that CD32 is an antigen uptake receptor on pDCs and that antigen presentation by pDCs is of particular relevance when circulating antibodies are present. Antigen presentation by pDCs may thus modulate the strength and quality of the secondary phase of an immune response.
Utilizing audit to evaluate improvements in continuous veno‐venous haemofiltration practices in intensive therapy unit
Authors: Richardson Annette , Reynolds Claire , Rodgers Rebecca
Published: June 2006

Continuous veno‐venous haemofiltration (CVVH) is used regularly in the management of acute renal failure in intensive therapy unit (ITU). A three‐staged approach was undertaken involving two audits of practice to improve CVVH record keeping in a 15‐bedded cardiac ITU. An initial baseline audit identified a number of areas for improvement in practice. The areas for improvement were implemented then a second audit was repeated. The improvements and practice changes included the dissemination of audit findings to the multidisciplinary team, redesigning the prescription chart to a more user‐friendly format and the development of a competency‐based CVVH workbook. This nurse‐led project demonstrated how positive outcomes and improvements could be achieved with record keeping across the multidisciplinary ITU team.
Tracheal intubation using the ILMA, C‐TrachTM or McCoy laryngoscope in patients with simulated cervical spine injury
Authors: Bilgin H. , Bozkurt M.
Published: June 2006

A study of 90 patients was undertaken to compare intubation success rates of using either ILMA, C‐TrachTM or McCoy laryngoscope in patients with simulated cervical spine injury. Insertion and intubation success rates, time taken to achieve intubation, airway complications and haemodynamic parameters were recorded. Insertion of ILMA and C‐TrachTM was successful at the first attempt in all patients. Intubation success rates were higher in the C‐Trach (100%) and McCoy (100%) groups than in the ILMA (87%) group. Total intubation time was significantly longer in the ILMA (63 s, SD 36.5) group than in the C‐Trach (41 s, SD 15.8) and McCoy (30 s, SD 7.4) groups (p < 0.05, p < 0.05, respectively). There were no significant differences in haemodynamic parameters among the groups at any time.
Geographical partitioning of goat diversity in Europe and the Middle East
Authors: Cañón J. , García D. , García‐Atance M. A. , Obexer‐Ruff G. , Lenstra J. A. , Ajmone‐Marsan P. , Dunner S. ,   The ECONOGENE Consortium
Published: June 2006

Thirty microsatellite markers were analysed in 1426 goats from 45 traditional or rare breeds in 15 European and Middle Eastern countries. In all populations inbreeding was indicated by heterozygosity deficiency (mean FIS = 0.10). Genetic differentiation between breeds was moderate with a mean FST value of 0.07, but for most (c. 71%) northern and central European breeds, individuals could be assigned to their breeds with a success rate of more than 80%. Bayesian‐based clustering analysis of allele frequencies and multivariate analysis revealed at least four discrete clusters: eastern Mediterranean (Middle East), central Mediterranean, western Mediterranean and central/northern Europe. About 41% of the genetic variability among the breeds could be explained by their geographical origin. A decrease in genetic diversity from the south‐east to the north‐west was accompanied by an increase in the level of differentiation at the breed level. These observations support the hypothesis that domestic livestock migrated from the Middle East towards western and northern Europe and indicate that breed formation was more systematic in north‐central Europe than in the Middle East. We propose that breed differentiation and molecular diversity are independent criteria for conservation.
Structural analogues of AMD3100 mobilise haematopoietic progenitor cells from bone marrow in vivo according to their ability to inhibit CXCL12 binding to CXCR4 in vitro
Authors: Martin Coralie , Bridger Gary J. , Rankin Sara M.
Published: June 2006

The CXCR4 antagonist, AMD3100, stimulates a rapid increase in circulating numbers of haematopoeitic progenitor cells (HPCs) in both mice and human healthy volunteers. An in situ perfusion system of the mouse femoral bone marrow was used to provide the first direct evidence that AMD3100 mobilises HPCs from the bone marrow. Structural analogues of AMD3100 demonstrated that the ability of these compounds to mobilise HPCs in vivo correlated with their capacity to antagonise CXCR4 in vitro. This model system was also used to demonstrate additive effects of AMD3100 administered acutely, with granulocyte colony‐stimulating factor administered chronically, with respect to HPC mobilisation.
AUG‐proximal nucleotides regulate protein synthesis in Leishmania tropica
Authors: Stanton Julie D. , Mensa‐Wilmot Kojo
Published: June 2006

Gene expression in the Leishmania is controlled post‐transcriptionally, and is likely to be impacted by both 5′ and 3′ untranslated regions (UTRs). We have investigated the effects of trinucleotides in the AUG‐proximal region (APR) (i.e. positions −3 to −1 upstream of an AUG) on two reporter genes in the context of an endogenous intergenic region of Leishmania tropica. The effects of APRs on protein expression were determined in stable transfectants in vivo. Three APRs, namely, C−3C−2C−1, ACC and GCC, yielded robust translation, whereas GTA produced low amounts of proteins. A purine at −3 of an APR was not crucial for efficient translation. Steady‐state level of reporter mRNA did not correlate directly with the amount of protein detected. Polysome analysis revealed that APRs modulate translation, at least in part, by influencing mRNA association with ribosomes. An analysis of genomic UTRs in L. major showed that (i) the consensus APR is N−3N−2C−1 (where N = any nucleotide), and (ii) the most frequently used APRs include ACA, ACC, ATC, GCC, GCG, GTC and CAC, some of which were translation enhancers in our experimental studies.
Involvement of wound‐induced receptor‐like protein kinase in wound signal transduction in tobacco plants
Authors: Takabatake Reona , Seo Shigemi , Ito Naoko , Gotoh Yoko , Mitsuhara Ichiro , Ohashi Yuko
Published: June 2006

The wound‐induced receptor‐like protein kinase (WRK) gene, isolated as one of the genes whose transcripts accumulated during the early period of N gene‐dependent synchronized cell death in tobacco mosaic virus‐infected tobacco plants, encodes a leucine‐rich repeat receptor‐like protein kinase, and its transcript was transiently increased 15 min after wounding. In the present study, analysis of a green fluorescent protein fusion protein indicated that WRK is localized in the plasma membrane. In transgenic tobacco plant lines with elevated or suppressed levels of WRK transcript, the wound‐induced accumulation of both basic PR‐1 and PR‐6 transcripts was slightly enhanced or significantly suppressed respectively. The decrease in wound‐induced basic PR gene expression in WRK suppressed lines was restored by jasmonic acid (JA) treatment. Furthermore, the levels of wound‐induced enzymatic activation of both salicylic acid‐induced protein kinase (SIPK) and wound‐induced protein kinase (WIPK) and wound‐induced accumulation of JA were reduced in the WRK suppressed lines in comparison with a control line. These results suggest that WRK functions upstream of SIPK and WIPK and regulates wound signal transduction in tobacco plants.
Co‐Authorship in Management and Organizational Studies: An Empirical and Network Analysis*
Authors: Acedo Francisco José , Barroso Carmen , Casanueva Cristóbal , Galán José Luis
Published: June 2006

In recent decades there has been growing interest in the nature and scale of scientific collaboration. Studies into co‐authorship have taken two different approaches. The first one attempts to analyse the reasons why authors collaborate and the consequences of such decision (Laband and Tollison, 2000). The second approach is based on the idea that co‐authorship creates a social network of researchers (Barabási et al., 2002; Moody, 2004; Newman, 2001). In this study we have carried out an exploratory analysis of co‐authorships in the field of management from the two aforementioned approaches. The results obtained show a growing tendency of the co‐authored papers in the field of management, similar to what can be observed in other disciplines. Our study analyses some of the underpinning factors, which have been highlighted in the literature, explaining this tendency. Thus, the progressive quantitative character of research and the influence of the collaboration on the articles' impact are enhanced. The network analysis permits the exploration of the peculiarities of the management in comparison with other fields of knowledge, as well as the existing linkages between the most central and prominent authors within this discipline.
Role of Knowledge in Value Creation in  Business Nets*
Authors: Möller Kristian , Svahn Senja
Published: June 2006

abstract This paper focuses on the role of knowledge in intentionally created business networks called nets. Nets are seen to offer firms collective benefits beyond those of a single firm or market transaction. We propose that the types of knowledge and learning required in the management of different types of business net are dependent on the value creation characteristics of the net types. Based on this we suggest a classification of three generic net types –‘current business nets’, ‘business renewal nets’, and ‘emerging new business nets’– and argue that they pose different conditions for management in nets. Using this framework and integrating notions from the industrial network approach, strategic management and dynamic capabilities view, and organizational learning we make a number of observations and propositions about the role of knowledge and learning in the three types of business net. The paper contributes to the emerging theory of network management.
Transferring Organizational Learning Systems to Japanese Subsidiaries in China*
Authors: Hong Jacky F. L. , Easterby‐Smith Mark , Snell Robin Stanley
Published: June 2006

abstract Qualitative interviews and observations were conducted to study the cross‐border transfer of organizational learning systems to the subsidiaries of five Japanese manufacturing companies operating in South China. This paper develops a holistic model of the overall process, by integrating knowledge‐oriented, routine‐oriented, and social/contextual perspectives, each of which plays a necessary role in explaining essential aspects. One feature of the transfer of organizational learning systems entailed arranging local access to, and opportunity to replicate, various types of knowledge repository that contained corporate values as well as technical expertise. A second feature involved the development of collective learning routines through dynamic interplay with evolving, locally based, knowledge repositories. A third feature, in two companies, entailed the creation of enterprise contexts that reproduced the socialization and corporate culture maintenance rituals, and the open plan factory and office designs, that were hallmarks of the respective parent companies, and which appeared highly conducive to the transfer of collective learning routines to the local sites. Findings indicate that successful cross‐border transfer of organizational learning systems entails the development and implementation of an overall heuristic design for cultivating collective learning routines through the engineering of enterprise contexts and the responsive management of knowledge repositories.
A Tale of Three Discourses: The Dominant, the Strategic and the Marginalized*
Authors: Heracleous Loizos
Published: June 2006

abstract  This study drew from a structurational view of discourse and employed a discourse analysis approach based on rhetoric and hermeneutics to analyse the organizational discourses operating in the UK operations of a global human resources consulting firm, People Associates. The aims were firstly to understand in what sense we can speak of ‘modes of discourse’ in organizational settings; secondly to explore the potential existence and nature of interrelations among different modes of discourse; and thirdly to explore the constructive potential of modes of discourse on their social and organizational contexts. The results suggest that modes of discourse can usefully be seen as rhetorical enthymemes constituted of relatively stable, normative structures and flexible, action‐oriented structures; that modes of discourse can interrelate through their deeper structural features, and can have mutually co‐optive or antagonistic relationships; and lastly that the constructive potential of discourse is based primarily on its deeper structures, and on the consonance of surface communicative actions with these structures. This research thus sheds light on fundamental definitional and substantive issues in organizational discourse; in particular offering a novel conceptualization of the nature of discourse, a further understanding of discursive interrelations, and finally one way to understand its constructive effects on social organizations.
The Interaction of Top Management Group, Stakeholder, and Situational Factors on Certain Corporate Reputation Management Activities*
Authors: Carter Suzanne M.
Published: June 2006

abstract  This study examines when a firm's members are most likely to promote and defend its reputation. Building on past research in impression management theory and the upper‐echelons perspective, I argue that firms facing increased visibility among different stakeholder groups will increase corporate reputation management activities towards those groups and decrease activities towards other groups. I further argue that top management group characteristics will moderate these relationships, suggesting that certain top management groups are more attuned to the situational needs of reputation management. A set of hypotheses are tested using pooled cross‐sectional time‐series data on a set of Fortune 500 companies. Results indicate that firms generally directed reputation management activities towards their more visible stakeholders. However, the type and extent of reputation management behaviour varied. Specifically, for firms whose top management groups were more highly educated or output oriented, highly visible situations with the media were more likely to be associated with a higher use of press releases. Moreover, those same firms devoted more resources to mass media advertising under situations of high consumer visibility compared to firms whose top management groups were less educated or throughput oriented.
Real‐time mud gas logging and sampling during drilling
Authors: ERZINGER J. , WIERSBERG T. , ZIMMER M.
Published: June 2006

Continuous mud gas loggings during drilling as well as offline mud gas sampling are standard procedures in oil and gas operations, where they are used to test reservoir rocks for hydrocarbons while drilling. Our research group has developed real‐time mud gas monitoring techniques for scientific drilling in non‐hydrocarbon formations mainly to sample and study the composition of crustal gases. We describe in detail this technique and provide examples for the evaluation of the continuous gas logs, which are not always easy to interpret. Hydrocarbons, helium, radon and with limitations carbon dioxide and hydrogen are the most suitable gases for the detection of fluid‐bearing horizons, shear zones, open fractures, sections of enhanced permeability and permafrost methane hydrate occurrences. Off‐site isotope studies on mud gas samples helped reveal the origin and evolution of deep‐seated crustal fluids.