bluuebunny/crossref_metadata_2025 huggingface dataset:
RNT‐1 regulation in C. elegans
Authors: Ji Yon Ju , Singaravelu Gunasekaran , Ahnn Joohong
Published: June 2005

RUNXs are important transcription factors, which are involved in animal development and human carcinogenesis. RNT‐1, the only homologue of RUNXs, in Caenorhabditis elegans (C. elegans) has been identified and viable mutant animals of rnt‐1 gene have been isolated and characterized recently. Genetic analyses using rnt‐1 mutants have shown that RNT‐1 is regulated by TGFβ‐ and Wnt‐signaling pathways in the body size regulation and male tail development. Here, we review our current understanding of RNT‐1 functions in these signaling pathways. Furthermore, future prospects of RNT‐1 and BRO‐1 studies in C. elegans are discussed in this review. © 2005 Wiley‐Liss, Inc.
Extracellular matrix‐dependent regulation of angiogenin expression in human placenta
Authors: Rajashekhar G. , Loganath Annamalai , Roy A.C. , Chong S.S. , Wong Y.C.
Published: June 2005

Knowledge of the rapidly developing hierarchy of controls affecting vascular development in placenta is required to understand how the growth factors and their receptor‐mediated signals actually produce vessels. At the cell biological level, these events clearly require stable interactions between the cells, and cells with the surrounding ECM. The objective of the study was to understand the role of integrins and ECM on the expression and secretion of angiogenin in placentas and from trophoblasts in culture. Functionally active term placental explant culture and trophoblast cultures were used to demonstrate the differential secretion profile of angiogenin and real‐time quantitative RT‐PCR to demonstrate the mRNA expression in the presence or absence of ECM proteins. In this study, a significant increase in expression and secretion of angiogenin occurred in the presence of vitronectin (VN) and fibronectin (FN). Using antibody‐blocking experiments it was also demonstrated that the angiogenin secretion is mediated by placental integrins, αVβ3 and α5β1. In addition, exposure to hypoxic conditions resulted in diminished angiogenin secretion in the presence of both ECMs suggesting that angiogenin expression in the presence of ECM is modulated by local O2 concentration. In conclusion, this study provides evidence for the regulatory role of ECM and integrins on the mRNA expression and secretion of angiogenin in human placenta. ECMs may have a pivotal role in enhancing secretion of this peptide necessary for placental angiogenesis and provides the impetus as additional targets for the control of angiogenesis in pathological pregnancy. © 2005 Wiley‐Liss, Inc.
Control of adenovirus packaging
Authors: Ostapchuk Philomena , Hearing Patrick
Published: June 2005

The results of studies of Adenovirus have contributed to our basic understanding of the molecular biology of the cell. While a great body of knowledge has been developed concerning Ad gene expression, viral replication, and effects on the infected host, the molecular details of the assembly process of Adenovirus particles are largely unknown. In this article, we would like to propose a theoretical model for the packaging and assembly of Adenovirus and present an overview of the studies that have contributed to our present understanding. In particular, we will summarize the molecular details of the process for packaging of viral DNA into virus particles and highlight the events in packaging and assembly that require further study. © 2005 Wiley‐Liss, Inc.
Regulation of parathyroid hypertensive factor secretion by vitamin D3 analogs in parathyroid cells derived from spontaneously hypertensive rats
Authors: Sutherland S.K. , Nemere I. , Benishin C.G.
Published: June 2005

Parathyroid hypertensive factor (PHF) is a novel substance secreted by the parathyroid gland (PTG), which is elevated in 30–40% of all hypertensive patients; specifically, the low‐renin subset. However, very little is known about the regulation of PHF secretion. Since the classical parathyroid regulator, 1,25‐dihydroxyvitamin D3 (1,25‐(OH)2D3), may be elevated concurrent with or preceding the development of low‐renin hypertension and elevated plasma PHF, we hypothesized that 1,25‐(OH)2D3 would stimulate PHF release. To test this hypothesis, PTG organ and cell cultures, derived from spontaneously hypertensive rats (SHR) and the normotensive genetic control Wistar Kyoto (WKY) rats, were exposed to various vitamin D3 metabolites and PHF release measured by ELISA. 1,25‐(OH)2D3 rapidly stimulated PHF release with enhanced sensitivity in SHR versus WKY cultures indicated by a leftward shift in the dose‐response curve, whereas 24,25‐dihydroxyvitamin D3 (24,25‐(OH)2D3) had the converse effect. Vitamin D3 analog “BT,” an agonist for the classical nuclear vitamin D receptor (1,25VDRnuc), was without effect suggesting a 1,25VDRnuc‐independent mechanism and potential involvement of the plasma membrane‐bound vitamin D receptor (1,25 D3‐MARRS). Interestingly, protein expression of the 1,25 D3‐MARRS was increased in SHR versus WKY parathyroid cells. In conclusion, these results support the idea that 1,25‐(OH)2D3 may contribute to elevated plasma PHF in the SHR. © 2005 Wiley‐Liss, Inc.
The potential promoter regions on the 5′ flank sequence of the mu opioid receptor gene in lymphocytes
Authors: Wei Erman , Li Pingfeng , Liu Xinhua , Qian Chaowei , Li Hui , Xia Weiyi , Li Gang
Published: June 2005

The human mu opioid receptor is known to mediate a variety of physiological and pharmacological effects of morphine in many tissues. However, the molecular processes that regulate the expression of the mu opioid receptor gene in immune cells are not well understood. To study regulatory elements that affect the expression of the mu opioid receptor gene in human lymphocytes (LMOR), a 2,278 bp fragment of the 5′ regulatory region of the mu opioid receptor gene was cloned and sequenced from CEM ×174 cells. The transcriptional initiation site was mapped through a primer extension assay. A series of 5′‐deleted plasmids were constructed and transiently transfected into cultured CEM ×174 cells. The data indicated that morphine up‐regulated the mRNA level of LMOR in a dose‐dependent manner, which could be blocked by the opioid receptor antagonist naloxone. Only one transcription initiation site (TIS) about 110 bp upstream of the translation start codon was identified. The regions from −372 to −253 and −2279 to −1371 located in the 5′ regulatory sequence of the mu opioid receptor gene contained enhancer elements, while the regions from −1371 to −968 and −650 to −370 possessed repressor elements. Those promoter elements were involved in the transcriptional regulation of the mu opioid receptor gene. Collectively, this data strongly indicates that the expression of the mu opioid receptor gene in lymphocytes is subject to the regulation of cis‐elements upstream from the TIS. © 2005 Wiley‐Liss, Inc.
Ryser's embedding problem for Hadamard matrices
Authors: Michael T. S.
Published: June 2005

What is the minimum order ${\cal R}\,(a, b)$ of a Hadamard matrix that contains an a by b submatrix of all 1's? Newman showed that

where c♯ denotes the smallest order greater than or equal to c for which a Hadamard matrix exists. It follows that if 4 divides both a and b, and if the Hadamard conjecture is true, then ${\cal R}(a,b)=ab$. We establish the improved bounds

for min {a,b} ≥ 2. The Hadamard conjecture therefore implies that if 4 divides both 2ab and ⌈a/2⌉ ⌈b/2⌉, then ${\cal R}$(a, b) = 2 ·  max {⌈a/2⌉b, ⌈b/2⌉a}. Our lower bound comes from a counting argument, while our upper bound follows from a sub‐multiplicative property of ${\cal R}$:

Improvements in our upper bound occur when suitable conference matrices or Bush‐type Hadamard matrices exist. We conjecture that any (1,−1)‐matrix of size a by b occurs as a submatrix of some Hadamard matrix of order at most ${\cal R}(a,b)$. © 2005 Wiley Periodicals, Inc. J Combin Designs
Effects of morphology and oxygen supply on schizophyllan formation by Schizophyllum commune using a pellet size controlling bioreactor
Authors: Shu Chin‐Hang , Chou Pou‐Fu , Hsu I‐Ching
Published: June 2005

The effects of mycelial morphology and oxygen supply on the production of the anti‐tumor polysaccharide from Schizophyllum commune were evaluated in this study. A pellet size controlling bioreactor has been used successfully for the production of the anti‐tumor polysaccharide of S commune. The average pellet size of mycelia in a bubble column bioreactor was around 20.5 mm in a typical run without using pellet size control. By forcing the fermentation broth through a pellet size control device with a stainless screen at five different fermentation times ranging from 1.0 to 4.5 days in each batch, different fungal pellet sizes ranging from 12.3 to 3.0 mm were achieved. The formation of anti‐tumor polysaccharide, schizophyllan (SPG), was significantly associated with the pellet morphology and oxygen supply rate. An optimal product yield of 0.29 g g−1 glucose was obtained when the pellet size was controlled at 12.3 mm. Oxygen transfer limitation inside the pellets was responsible for the formation of entrapped polysaccharide. Maximum entrapped SPG yield (Yp/s entrapped) of 0.88 g g−1 glucose occurred at the optimal pellet size of 12.3 mm. Copyright © 2005 Society of Chemical Industry
Anisotropic a posteriori error estimation for the mixed discontinuous Galerkin approximation of the Stokes problem
Authors: Creusé Emmanuel , Nicaise Serge
Published: June 2005

This article presents a posteriori error estimates for the mixed discontinuous Galerkin approximation of the stationary Stokes problem. We consider anisotropic finite element discretizations, i.e., elements with very large aspect ratio. Our analysis covers two‐ and three‐dimensional domains. Lower and upper error bounds are proved with minimal assumptions on the meshes. The lower error bound is uniform with respect to the mesh anisotropy. The upper error bound depends on a proper alignment of the anisotropy of the mesh, which is a common feature of anisotropic error estimation. In the special case of isotropic meshes, the results simplify, and upper and lower error bounds hold unconditionally. The numerical experiments confirm the theoretical predictions and show the usefulness of the anisotropic error estimator. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2006
Study on siloxane‐modified polyurethane dispersions from various polydimethylsiloxanes
Authors: Chen Ruei‐Shin , Chang Chih‐Jen , Chang Yih‐Her
Published: June 2005

In this work, various polydimethylsiloxanes (PDMS) are incorporated with isophorone diisocyanate (IPDI), 2,2‐bis(hydroxymethyl)propionic acid (DMPA), and poly(tetramethylene oxide) (PTMO) by the prepolymer process to synthesize a series of siloxane‐modified polyurethane dispersions (PUDs) with 35 wt % solid content, viscosities of 20–100 cps, and particle sizes of 40–130 nm. Hydrophobic PDMS was introduced into the PU chain either based on random distribution or through the block segment arrangement. We also establish the composition‐property relationship of PDMS‐PUD, which includes PDMS's type and molecular weight and PDMS‐PUD film's contact angle and mechanical property. The tensile strength of PDMS‐PUD film is decreased with increasing amount of PDMS. Scanning electron microscopy for chemical element analysis indicated that PDMS migrated to the surface much more easily in the block arrangement than in the random distribution. Also, some PDMS‐PUD films show a peau‐like surface, so their PUDs are considered promising to be used in processes for textiles. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3482–3490, 2005
Cylindrical polymer brushes
Authors: Zhang Mingfu , Müller Axel H. E.
Published: June 2005

In recent years, research on cylindrical polymer brushes (or molecular bottlebrushes) has received significant attention. In this article, we discuss various strategies for their synthesis and the unique properties arising from their regular multibranched structure. Some recent advances in the application of cylindrical polymer brushes are highlighted. Amphiphilic core– shell cylindrical polymer brushes, for example, have been successfully used as single molecular templates for inorganic nanoparticle formation. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3461–3481, 2005
DFT conformational studies of the HI‐6 molecule
Authors: Silva Gustavo R. , Borges Itamar , Figueroa‐Villar Jose D.
Published: June 2005

A systematic study of the oxime HI‐6 [1‐(2‐hydroxyiminomethyl‐1‐pyridinium)‐1‐(4‐carboxy‐aminopyridinium)dimethyl ether] hydrochloride, which is one of the most promising antidotes against soman intoxication, was carried out using density functional theory with the B3LYP (Becke, Lee, Yang, and Parr) method and the 6‐31+G*, 6‐31+G*, and 6‐31+G** basis sets. Rotational barriers, equilibrium geometries, and charge distributions were calculated in order to investigate the role of the side chain for the larger oximes used as antidotes in the treatment of neurotoxic organophosphate poisoning. Also reported is the comparison between HI‐6 and pralidoxime (2‐PAM), a smaller oxime previously studied in our research group. It is shown that conformation minima for the protonated E isomer do not depend on the size of the side chain; on the other hand, this effect has a pronounced influence on the protonated Z isomer. For the unprotonated isomers, other effects, such as electrostatic interactions and resonance, should be taken into account in their conformational analysis. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Theoretical study of adsorption of methyltert‐butyl ether on broken clay minerals surfaces
Authors: Michalkova A. , Johnson L. D. , Gorb L. , Zhikol O. A. , Shishkin O. V. , Leszczynski J.
Published: June 2005

The interactions between methyltert‐butyl ether (MTBE) and differently defected tetrahedral and octahedral fragments of clay minerals containing Si4+, Al3+, and Mg2+central cations have been studied at the B3LYP and MP2 levels of theory in conjunction with the 6‐31G(d) basis set. MTBE interacts with defect clay structures due to the formation of multiple CH…O and OH…O hydrogen bonds. Interactions of MTBE with systems containing different types of defected mineral fragments were found to vary. Systems containing the same type of defected mineral fragment with different central cation interact almost the same way with MTBE. The formation of hydrogen bonds leads to changes in the geometrical parameters and to the polarization of MTBE. The values of the interaction energies depend on the charge of the mineral fragment. They amount to 5 kcal/mol–35 kcal/mol. MTBE interacts more preferably with octahedral fragments than with tetrahedral fragments that contain an Al3+central cation. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Characterization of moenomycin antibiotics from medicated chicken feed by ion‐trap mass spectrometry with electrospray ionization
Authors: Eichhorn Peter , Aga Diana S.
Published: June 2005

The antimicrobial moenomycin, commonly used as a growth promoter in livestock, was isolated from medicated chicken feed. The purified extract was subjected to reversed‐phase liquid chromatographic separation followed by structural characterization using ion‐trap mass spectrometry (ITMS), which allowed identification of five moenomycins (A, A12, C1, C3, and C4) as the major components. The fragmentation patterns of the protonated and deprotonated moenomycin molecules, as well as of a series of sodium adducts, were investigated using ITMS after electrospray ionization. While the protonated molecules [M+H]+ proved highly unstable and underwent extensive in‐source fragmentation, isolation and activation of the [MH]− ions (m/z 1580 for moenomycin‐A) yielded simple mass spectra with a dominant base peak corresponding to the loss of the carboxy‐glycol and the C25‐hydrocarbon chain (m/z 1152 for moenomycin‐A). Further study of this fragment ion in an MS3 experiment gave rise to a peculiar product ion (m/z 902 for moenomycin‐A) that was attributed to the expulsion of a carbohydrate moiety representing a central building block of the linear molecule. In positive ion mode the generation of the mono‐sodiated adduct ions, [M+Na]+, was promoted by amending the mobile phase with 100 µM sodium acetate, but this also resulted in higher adducts of the type [M+2NaH]+ and [M+3Na2H]+ arising from the formation of the sodium salts of the phosphate acid diester and subsequently of the carboxylic acid. Substantial differences among the fragment‐rich product ion profiles of the three species were observed, and could in part be traced back to the mode of complexation of the additional sodium cation(s). Copyright © 2005 John Wiley & Sons, Ltd.
Transmembrane Ca2+ gradient is essential for high anion transport activity of human erythrocytes
Authors: Tu Y. P. , Feng C. , Xu H. , Guang Z. Y. , Lu Q. W. , Yang F. Y.
Published: June 2005

The role of a transmembrane Ca2+ gradient in anion transport by Band 3 of human resealed erythrocyte ghosts has been studied. The results show that a transmembrane Ca2+ gradient is essential for the conformation of erythrocyte Band 3 with higher anion transport activity. The dissipation of the transmembrane Ca2+ gradient by the ionophore A23187 inhibits the anion transport activity. The extent of this inhibition approaches 90% as the Ca2+ concentration on both sides of the ghost membrane is increased to 1.0 mM and half-maximum inhibition is observed at 0.25 mM Ca2+. Addition of ATP (0.4 mM) to the resealing medium can partly reestablish the transmembrane Ca2+ gradient by activation of Ca2+-ATPase and alleviate the inhibition to some extent. N-ethylmaleimide, an inhibitor of erythrocyte Ca2+-ATPase, prevents such restoration. Electron micrographs reveal that numerous larger intramembranous particles can be observed on the P-faces of freeze-fractured resealed ghosts in the absence of a transmembrane Ca2+ gradient.
Parathyroid hormone co-stimulation of hepatocyte proliferation is sensitive to protein kinase A and calcium channel inhibitors
Authors: Skouteris George G.
Published: June 2005

Parathyroid hormone (PTH) mobilises calcium in the hepatocyte, an effect which is abolished by verapamil and staurosporine. In our study parathyroid hormone was shown to act additively to dHGF in inducing hepatocyte DNA synthesis. It is also shown that PTH induced the production of inositol 1,4,5 trisphosphate (IP3) and c-fos expression at early times in culture. Co-incubation of PTH and dHGF with a c-fos antisense oligodeoxynucleotide inhibited hepatocyte DNA synthesis, indicating that the additive effect of PTH is correlated with the induction of c-fos. H-89, a PKA specific inhibitor, inhibited the PTH effect on IP3 production as well as the PTH effect on hepatocyte DNA synthesis. Verapamil and staurosporine also inhibited the PTH effect in dHGF-induced DNA synthesis. Therefore it is suggested that PKA mediated at a great extent the co-stimulatory effects of PTH on hepatocyte proliferation via IP3 production.
Anxiety sensitivity as a predictor of labor pain
Authors: Lang Ariel J. , Sorrell John T. , Rodgers Carie S. , Lebeck Meredith M.
Published: June 2005

Psychosocial factors have been implicated in the pain experience during childbirth, which can have both short‐ and long‐term consequences on the mother's health and her relationship with her infant. The present study evaluated important demographic, social, and psychological factors as predictors of multiple dimensions of labor pain among 35 mothers during childbirth. The results indicated that anxiety sensitivity (AS), as measured by the Anxiety Sensitivity Index, shared a significant relation with maximum pain during labor as well as sensory and affective components of pain as measured by the McGill Pain Questionnaire. AS predicted both maximum pain during labor and sensory aspects of pain above and beyond demographic and social factors as well as other theoretically important psychological factors (e.g., depression and state anxiety). These data replicate previous research that has demonstrated the significant impact of AS on pain responding in other areas (e.g., chronic pain) and extend knowledge in this literature to demonstrate the important role that AS serves among women and their experience of labor pain. Clinical implications are highlighted and discussed.
The coupling mechanism of P‐glycoprotein involves residue L339 in the sixth membrane spanning segment
Authors: Rothnie Alice , Storm Janet , McMahon Roisin , Taylor Andrew , Kerr Ian D. , Callaghan Richard
Published: June 2005

The transmembrane (TM) domains in P‐glycoprotein (P‐gp) contain the drug binding sites and undergo conformational changes driven by nucleotide catalysis to effect translocation. However, our understanding of exactly which regions are involved in such events remains unclear. A site‐directed labelling approach was used to attach thiol‐reactive probes to cysteines introduced into transmembrane segment 6 (TM6) in order to perturb function and infer involvement of specific residues in drug binding and/or interdomain communication. Covalent attachment of coumarin‐maleimide at residue 339C within TM6 resulted in impaired ATP hydrolysis by P‐gp. The nature of the effect was to reduce the characteristic modulation of basal activity caused by transported substrates, modulators and the potent inhibitor XR9576. Photoaffinity labelling of P‐gp with [3H]‐azidopine indicated that residue 339C does not alter drug binding per se. However, covalent modification of this residue appears to prevent conformational changes that lead to drug stimulation of ATP hydrolysis.
Development and evaluation of catch per unit effort indices for southern blue whiting (Micromesistius australis) on the Campbell Island Rise, New Zealand
Authors: Hanchet Stuart M. , Blackwell Ron G. , Dunn Alistair
Published: June 2005

This paper develops standardized commercial cpue indices for a highly aggregated spawning fishery in New Zealand waters, and verifies the indices using fishery-independent data. Indices were calculated for all vessels using three different measures of effort, and for vessel subsets based on processing type (surimi and dressed), and relative experience in the fishery. Trends in cpue were consistent with trends in fishery-independent acoustic surveys, age composition of the commercial catch, and recent stock assessment results. In particular, the cpue indices tracked the more than fourfold increase in abundance from 1993 to 1996 associated with the recruitment of the strong 1991 year class, and the decline in relative abundance as this year class was fished down. Despite this being a highly aggregated spawning fishery, there was little evidence for hyperstability. There were also significant differences in fishing strategies of the fleets between periods of high and low fish abundance.
Psychosocial impairment in offspring of depressed parents
Authors: LEWINSOHN PETER M. , OLINO THOMAS M. , KLEIN DANIEL N.
Published: June 2005

Background. Offspring of depressed parents experience impairment in a number of domains of functioning. Few studies have examined the impact of both maternal and paternal depression and co-morbid psychopathology on offspring functioning.

Method. Oregon Adolescent Depression Project participants were administered diagnostic interviews and completed measures of psychosocial functioning during adolescence (mean=16·6, S.D.=1·19) and again during young adulthood (mean=24·5, S.D.=0·51). Diagnostic interviews were also conducted with the mothers and fathers of the target individual.

Results. After controlling for relevant demographic characteristics, parental co-morbid psychopathology, and offspring psychopathology, maternal depression was associated with higher levels of physical symptoms (β=0·14, S.E.=0·07) during adolescence, and higher levels of minor stressors (β=2·52, S.E.=1·07) and a greater risk for using mental health services (OR 1·86, 95% CI 1·14–3·03) in young adulthood. Paternal depression was associated with offspring experiencing more major stressors (β=0·27, S.E.=0·07), having lower perceived social competence (β=−0·17, S.E.=0·08), and being more likely to attempt suicide (OR 2·65, 95% CI 1·19–5·92) during adolescence, as well as lower perceived social competence (β=−1·21, S.E.=0·49) in young adulthood.

Conclusions. Offspring of depressed parents demonstrate impairment in a variety of domains, even after controlling for the effects of their own psychopathology. Further research on the mechanisms that lead to these impairments, as well as the role of these impairments in the subsequent development of psychopathology, is warranted.
Heritability of life satisfaction in adults: a twin-family study
Authors: STUBBE J. H. , POSTHUMA D. , BOOMSMA D. I. , De GEUS E. J. C.
Published: June 2005

Background. Subjective well-being (SWB) can be partitioned into the components life satisfaction and affect. Research on factors influencing these components of well-being has mainly focused on environmental characteristics. The aim of this study was to investigate the relative contribution of genes and environment to individual differences in life satisfaction in a large sample of Dutch twins and their singleton siblings.

Method. Life satisfaction of 5668 subjects registered with The Netherlands Twin Registry (NTR) was measured with a Dutch version of the self-reported Satisfaction with Life Scale. An extended twin design was used to obtain correlations in life satisfaction scores for monozygotic twins, dizygotic twins and sibling pairs and to estimate the contribution of genes and environment to the variation in life satisfaction.

Results. No differences between males and females were found in the mean level of life satisfaction. Broad-sense heritability was 38%. Non-additive genetic factors explained all or most of the genetic influences. The remaining 62% of the variance in life satisfaction could be attributed to unique environmental factors, both persistent and transitory, plus measurement error.

Conclusions. Individual differences in life satisfaction are determined in part by genetic factors that are largely or entirely non-additive in nature.
Thermochemical remanent magnetization in Precambrian rocks: Are we sure the geomagnetic field was weak?
Authors: Smirnov A. V. , Tarduno J. A.
Published: June 2005

Thellier paleointensity determinations from two dikes of the Early Proterozoic (∼2.46 Ga) Matachewan dike swarm (Canada) yield field values of 2.14 ± 0.18 and 9.81 ± 1.65 μT. Corresponding values of virtual axial dipole moment are very low (0.54 ± 0.05 × 1022 and 2.49 ± 0.42 × 1022 Am2, respectively) when compared with the modern field. The characteristic remanent magnetization (ChRM) was isolated over a narrow range of high unblocking temperatures (∼520–580°C). Detailed rock magnetic analyses indicate that the ChRM is carried by nearly stoichiometric pseudo single domain magnetite. Scanning electron microscopy (SEM) reveals that the magnetite is in the form of fine intergrowths with ilmenite, formed by oxyexsolution during cooling. The high‐temperature oxidation defined in the SEM images could have continued at temperatures below the Curie point of magnetite. In this case, the ChRM would be a thermochemical remanent magnetization (TCRM) rather than a thermal remanent magnetization (TRM). Estimates of the TCRM/TRM ratio show that the Thellier data could underestimate the true field value by a factor of 4 without violating experimental selection criteria. This uncertainty in TRM fidelity translates into a potential range of field values that spans that defined by the modern field (∼8 × 1022 Am2) and proposed low Precambrian levels (∼2 × 1022 Am2). Therefore understanding further how TCRM is acquired and records the field represents a major challenge if these and many other similar rocks are to be used in Thellier studies aimed at defining the strength of the Precambrian field.
Silica fluxes in the northeast Atlantic frontal zone of Mode Water formation (38°–45°N, 16°–22°W) in 2001–2002
Authors: Mosseri Julie , Quéguiner Bernard , Rimmelin Peggy , Leblond Nathalie , Guieu Cécile
Published: June 2005

The biogenic (BSi) and lithogenic (LSi) silica export fluxes were investigated in the northeast Atlantic (38°–45°N, 16°–22°W) as part of the Programme Océan Multidisciplinaire Méso Echelle (POMME) program in 2001–2002. They were measured at four stations located on both sides of a frontal zone (40°–42°N) by means of permanent moorings of sediment traps deployed at 400 and 1000 m depth. Averaged over the area, the annual BSi fluxes (corrected from 230Th trapping efficiencies) ranged between 0.240 mmol m−2 d−1 at 400 m to 0.316 mmol m−2 d−1 at 1000 m. The bulk annual BSi fluxes are comparable to bulk BSi export fluxes recorded for oligotrophic areas. The annual export flux of LSi (range 0.029 mmol m−2 d−1 at 400 m to 0.054 mmol m−2 d−1 at 1000 m) was lower than BSi and accounted for 10% of the total silica export flux. Results show a strong coupling between the two siliceous particulate fractions, which is interpreted as reflecting LSi scavenging by BSi and limitation of BSi production in surface water by lithogenic (trace metals) inputs. BSi export was maximum at the beginning of the productive season during the spring bloom. However, annual BSi export fluxes in 2001 were quite higher at 400 m in the southern area (e.g., 0.249–0.288 at the southeast station versus 0.211 mmol BSi m−2 d−1 at the northeast station) contradictory to the classical south‐north surface production increase. We suggest an advective lateral transport within the upper 400 m of siliceous particles from the northern, more productive area to the southern region.
Evaluation of global wind power
Authors: Archer Cristina L. , Jacobson Mark Z.
Published: June 2005

The goal of this study is to quantify the world's wind power potential for the first time from data. Wind speeds are calculated at 80 m, the hub height of modern, 77‐m diameter, 1500 kW turbines. Since relatively few observations are available at 80 m, the Least Square extrapolation technique is utilized and revised here to obtain estimates of wind speeds at 80 m given observed wind speeds at 10 m (widely available) and a network of sounding stations. Tower data from the Kennedy Space Center (Florida) were used to validate the results. Globally, ∼13% of all reporting stations experience annual mean wind speeds ≥ 6.9 m/s at 80 m (i.e., wind power class 3 or greater) and can therefore be considered suitable for low‐cost wind power generation. This estimate is believed to be conservative. Of all continents, North America has the largest number of stations in class ≥ 3 (453), and Antarctica has the largest percent (60%). Areas with great potential are found in northern Europe along the North Sea, the southern tip of the South American continent, the island of Tasmania in Australia, the Great Lakes region, and the northeastern and northwestern coasts of North America. The global average 10‐m wind speed over the ocean from measurements is 6.64 m/s (class 6); that over land is 3.28 m/s (class 1). The calculated 80‐m values are 8.60 m/s (class 6) and 4.54 m/s (class 1) over ocean and land, respectively. Over land, daytime 80‐m wind speed averages obtained from soundings (4.96 m/s) are slightly larger than nighttime ones (4.85 m/s); nighttime wind speeds increase, on average, above daytime speeds above 120 m. Assuming that statistics generated from all stations analyzed here are representative of the global distribution of winds, global wind power generated at locations with mean annual wind speeds ≥ 6.9 m/s at 80 m is found to be ∼72 TW (∼54,000 Mtoe) for the year 2000. Even if only ∼20% of this power could be captured, it could satisfy 100% of the world's energy demand for all purposes (6995–10177 Mtoe) and over seven times the world's electricity needs (1.6–1.8 TW). Several practical barriers need to be overcome to fully realize this potential.
Madden‐Julian Oscillation
Authors: Zhang Chidong
Published: June 2005

The Madden‐Julian Oscillation (MJO) is the dominant component of the intraseasonal (30–90 days) variability in the tropical atmosphere. It consists of large‐scale coupled patterns in atmospheric circulation and deep convection, with coherent signals in many other variables, all propagating eastward slowly (∼5 m s−1) through the portion of the Indian and Pacific oceans where the sea surface is warm. It constantly interacts with the underlying ocean and influences many weather and climate systems. The past decade has witnessed an expeditious progress in the study of the MJO: Its large‐scale and multiscale structures are better described, its scale interaction is recognized, its broad influences on tropical and extratropical weather and climate are increasingly appreciated, and its mechanisms for disturbing the ocean are further comprehended. Yet we are facing great difficulties in accurately simulating and predicting the MJO using sophisticated global weather forecast and climate models, and we are unable to explain such difficulties based on existing theories of the MJO. It is fair to say that the MJO remains an unmet challenge to our understanding of the tropical atmosphere and to our ability to simulate and predict its variability. This review, motivated by both the acceleration and gaps in our knowledge of the MJO, intends to synthesize what we currently know and what we do not know on selected topics: its observed basic characteristics, mechanisms, numerical modeling, air‐sea interaction, and influences on the El Niño and Southern Oscillation.
The recent turnaround in stratospheric ozone over northern middle latitudes: A dynamical modeling perspective
Authors: Hadjinicolaou P. , Pyle J. A. , Harris N. R. P.
Published: June 2005

The past trends in stratospheric ozone are assessed in this study using chemical‐transport model (CTM) simulations and statistical trend analysis. The SLIMCAT CTM is forced by the ERA‐40 ECMWF analyses in decadal integrations using a simplified stratospheric chemistry scheme (with fixed halogen loading at the 1980s levels and no heterogeneous chemistry), in order to reveal the influence of meteorology on ozone variability and trends. The year‐to‐year model ozone variations compare well with the merged TOMS and SBUV measurements from 1979 to present in the Northern Hemisphere (NH) and the long‐term model ozone anomalies, relative to 1980, capture a large part of the observed changes, especially the strong positive tendency after the mid‐1990s. A linear regression analysis of the total ozone time‐series shows that around one‐third of the observed downward trend during 1979–1993 and, within the uncertainties, all of the observed upward trend from 1994 to 2003 are reproduced by the model which is forced only by transport changes. This highlights the potentially important role of dynamics in the attribution of the future ozone recovery.
Laboratory measurements of smoke optical properties from the burning of Indonesian peat and other types of biomass
Authors: Chand D. , Schmid O. , Gwaze P. , Parmar R. S. , Helas G. , Zeromskiene K. , Wiedensohler A. , Massling A. , Andreae M. O.
Published: June 2005

We present the first results on optical properties (λ ∼ 540 nm) of fresh aerosols from the combustion of Indonesian peat, German peat and other types of biomass, measured under controlled laboratory conditions. The mass scattering and mass absorption efficiencies for Indonesian and German peat aerosols are in the range of 6.0–8.1 and 0.04–0.06 m2 g−1, respectively. A very high single scattering albedo (0.99) is observed for the peat smoke aerosols, reflecting the smoldering burning conditions (emission ratio, ΔCO/ΔCO2 = 19–50%). The relative increase in light scattering (f(RH)) due to an increase in relative humidity (RH) from 15% to 90% is very low (i.e., f(90) = 1.05) for both Indonesian and German peat aerosols. This value is considerably smaller than for aged Indonesian peat smoke particles (f(80) = 1.65) [Gras et al., 1999]. This suggests that atmospheric aging processes may be an important factor for aerosol hygroscopicity.
Partitioning between resolved wave forcing and unresolved gravity wave forcing to the quasi‐biennial oscillation as revealed with a coupled chemistry‐climate model
Authors: Shibata Kiyotaka , Deushi Makoto
Published: June 2005

The quasi‐biennial oscillation (QBO) in the equatorial stratosphere is simulated with general circulation models that include full stratospheric chemistry. One model treats ozone as an interactive species between radiation and chemistry, while the other treats it as a non‐interactive species. The dynamical module employs T42 truncation and 68 layers with vertical spacing of about 500 m in the stratosphere. A non‐orographic gravity wave drag scheme and the weakening of the horizontal diffusion are also introduced. QBOs of about 27 and 31 months periods are reproduced by the two models. Resolved wave and unresolved gravity wave forcings are found to be of similar magnitude, but their temporal behaviors have different phase relations to zonal‐mean zonal wind. The resolved waves exert eastward forcing mainly in the westward‐wind phase, while the unresolved gravity waves deposit eastward momentum mostly in the eastward‐wind phase. Similar temporal partitioning can be seen in the westward acceleration period.
The importance of China's household sector for black carbon emissions
Authors: Streets David G. , Aunan Kristin
Published: June 2005

The combustion of coal and biofuels in Chinese households is a large source of black carbon (BC), representing about 10–15% of total global emissions during the past two decades, depending on the year. How the Chinese household sector develops during the next 50 years will have an important bearing on future aerosol concentrations, because the range of possible outcomes (about 550 Gg yr−1) is greater than total BC emissions in either the United States or Europe (each about 400–500 Gg yr−1). In some Intergovernmental Panel on Climate Change scenarios biofuels persist in rural China for at least the next 50 years, whereas in other scenarios a transition to cleaner fuels and technologies effectively mitigates BC emissions. This paper discusses measures and policies that would help this transition and also raises the possibility of including BC emission reductions as a post‐Kyoto option for China and other developing countries.
Internal and forced modes of variability in the Indian Ocean
Authors: Bracco A. , Kucharski F. , Molteni F. , Hazeleger W. , Severijns C.
Published: June 2005

Ocean‐atmosphere variability in the tropical Indian Ocean is investigated using observational data and ensemble experiments with a coupled general circulation model. In one ensemble (IO runs) the ocean‐model domain is limited to the Indian Ocean and observed sea surface temperatures force the atmospheric model elsewhere. In a second ensemble (TPIO) the coupled domain includes the Tropical Pacific. The IO runs display a coupled mode of variability with several characteristics of the Indian Ocean Dipole (IOD), but independent on ENSO (El‐Niño Southern Oscillation). Changes in the Walker circulation induced by ENSO are insufficient to trigger IOD events. In the TPIO runs ENSO variability is correlated with the IOD mode as observed. Oceanic processes are responsible for an essential component of ENSO forcing in the Indian Ocean. The ENSO phase conditions the thermocline depth in the Indonesian Throughflow region and in the southeastern IO. TPIO results are in agreement with SODA reanalysis.
An exercise in forecasting loop current and eddy frontal positions in the Gulf of Mexico
Authors: Oey L.‐Y. , Ezer T. , Forristall G. , Cooper C. , DiMarco S. , Fan S.
Published: June 2005

As part of a model‐evaluation exercise to forecast Loop Current and Loop Current eddy frontal positions in the Gulf of Mexico, the Princeton Regional Ocean Forecast System (PROFS) is tested to forecast 14 4‐week periods Aug/25/99–Sep/20/00, during which a powerful eddy, Eddy Juggernaut (Eddy‐J) separated from the Loop Current and propagated southwestward. To initialize each forecast, PROFS assimilates satellite sea surface height (SSH) anomaly and temperature (SST) by projecting them into subsurface density using a surface/subsurface correlation that is a function of the satellite SSH anomaly. The closest distances of the forecast fronts from seven fixed stations in the northern Gulf over a 4‐week forecast horizon are then compared against frontal observations derived primarily from drifters. Model forecasts beat persistence and the major source of error is found to be due to the initial hindcast fields.
Spin waves in a periodically layered magnetic nanowire
Authors: Kruglyak V. V. , Hicken R. J. , Kuchko A. N. , Gorobets V. Yu.
Published: June 2005

We report a simple theoretical derivation of the spectrum and damping of spin waves in a cylindrical periodically structured magnetic nanowire (cylindrical magnonic crystal) in the “effective-medium” approximation. The dependence of the “effective” magnetic parameters upon the individual layer parameters is shown to be different from the arithmetic average over the volume of the superlattice. The formulas that are obtained can be applied firstly in the description of spin-wave dispersion in the first allowed band of the structure and secondly in the design of a magnonic crystal with band gaps in an arbitrary part of the spin-wave spectrum.
High-resolution strain mapping in heteroepitaxial thin-film features
Authors: Murray C. E. , Yan H.-F. , Noyan I. C. , Cai Z. , Lai B.
Published: June 2005

Heteroepitaxial thin-film features that are lattice matched to the underlying substrate undergo elastic relaxation at the free edges of the feature. To characterize the degree of elastic relaxation, we employed synchrotron-based x-ray diffraction techniques to map the change in lattice spacing in the thin film at a submicron resolution. Measurements were conducted on 0.24-μm thick, heteroepitaxially grown SiGe strips of various widths on Si (001). A comparison of the SiGe diffraction peak positions across the features provides a real-space mapping of the extent of elastic relaxation as a function of linewidth. The resultant in-plane normal film stress measurements were compared to calculated values from several elastic mechanical models to assess their validity in predicting stress distributions within the features.
Relating kinetic rates and local energetic roughness by accelerated molecular-dynamics simulations
Authors: Hamelberg Donald , Shen Tongye , Andrew McCammon J.
Published: June 2005

We show that our accelerated molecular-dynamics (MD) approach can extend the time scale in all-atom MD simulations of biopolymers. We also show that this technique allows for the kinetic rate information to be recaptured. In deducing the kinetic rates, the relationship between the local energetic roughness of the potential-energy landscape and the effective diffusion coefficient is established. These are demonstrated on a very slow but important biomolecular process: the dynamics of cis–trans-isomerization of Ser–Pro motifs. We do not only recapture the slow kinetic rates, which is difficult in traditional MD, but also obtain the underlying roughness of the energy landscape of proteins at atomistic resolution.
Comment on “Analysis of hydroxyl group controlled atomic layer deposition of hafnium oxide from hafnium tetrachloride and water” [J. Appl. Phys. 95, 4777 (2004)]
Authors: Alam M. A. , Green M. L.
Published: June 2005

In this comment we address issues raised by Puurunen in a paper comparing our model of atomic layer deposition (ALD) growth to Puurunen’s. The main conclusion is that our models are fundamentally different. In our model, we employ two differential equations, describing the deposition of HfO2 per cycle, and the creation rate of new OH groups per cycle. These two equations enable us to explain all observed ALD growth behaviors related to the concentration of OH nucleation sites. Puurunen’s model is essentially geometry based, and takes into account the concentration of nucleation sites, but contains no equation analogous to our second differential equation describing the evolution of OH groups from cycle to cycle. We then go on to address several specific points that Puurunen raised.
Crossover from capacitive to pseudoinductive charge-relaxation in organic∕polymeric light-emitting diodes
Authors: Castro F. A. , Bueno P. R. , Graeff C. F. O. , Nüesch F. , Zuppiroli L. , Santos L. F. , Faria R. M.
Published: June 2005

In this work we propose a phenomenological microscopic approach to deal with pseudoinductive charge-relaxation processes (named also as negative capacitance phenomena) in organic molecules (tris-8-hydroxyquinoline-aluminum) and polymeric [poly(2-metoxy-5-(2′-etil-hexiloxy)-1,4-phenylene vinylene)] light-emitting diodes (OLEDs and PLEDs, respectively). The approach is based mainly on the fact that the recombination rate is higher than the slower carrier transit time to reach the recombination zone. The approach is supported by the fact that in both PLEDs and OLEDs, the strong pseudoinductive relaxation process was mainly observed when electron-hole recombination takes place, suggesting this is a recombination dependent phenomenon. Besides, the negative branch, in the real part of the complex capacitance representation as a function of the frequency, was not observed in PLED homopolar devices.
Effects of Hand Orientation and Delay on the Verbal Judgment of Haptically Perceived Orientation
Authors: Zuidhoek Sander , Kappers Astrid M L , Postma Albert
Published: June 2005

We examined the haptic perception of orientations of a single bar throughout the horizontal plane using a verbal response: participants were to assign a number of minutes to the orientation of a bar defined with respect to the stimulus table. Performance was found to be systematically biased. Deviations were consistent with, yet much smaller than, those resulting from haptic motor matching tasks. The size and direction of the deviations were found to correlate with hand orientation, and not to depend on spatial location per se, suggesting a role for hand-centred reference frames in biasing performance. Delaying the response by 10 s led to a small improvement only of right-hand perceptions, indicating different hemispheric involvement in processes involved in retaining and/or recoding of haptic orientation information. Also the haptic oblique effect was found with the current verbal response. Importantly, it was affected neither by hand orientation nor by delay, suggesting that the oblique effect is independent of the aforementioned deviations in orientation perception.
Perceiving Possibilities for Action: On the Necessity of Calibration and Perceptual Learning for the Visual Guidance of Action
Authors: Fajen Brett R
Published: June 2005

Tasks such as steering, braking, and intercepting moving objects constitute a class of behaviors, known as visually guided actions, which are typically carried out under continuous control on the basis of visual information. Several decades of research on visually guided action have resulted in an inventory of control laws that describe for each task how information about the sufficiency of one's current state is used to make ongoing adjustments. Although a considerable amount of important research has been generated within this framework, several aspects of these tasks that are essential for successful performance cannot be captured. The purpose of this paper is to provide an overview of the existing framework, discuss its limitations, and introduce a new framework that emphasizes the necessity of calibration and perceptual learning. Within the proposed framework, successful human performance on these tasks is a matter of learning to detect and calibrate optical information about the boundaries that separate possible from impossible actions. This resolves a long-lasting incompatibility between theories of visually guided action and the concept of an affordance. The implications of adopting this framework for the design of experiments and models of visually guided action are discussed.