bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies to Evaluate COBIT's Contribution to Organisations: Opportunities from the Literature, 2003–06
Authors: Ridley Gail , Young Judy , Carroll Peter
Published: November 2008

Information Technology control frameworks such as the Control Objectives for Information and Related Technology (COBIT) are designed to promote effective IT governance. This paper guides future scholarly evaluations of COBIT by identifying gaps in, and facilitating, research. It uses a framework to update a classification of the COBIT literature, by examining publications that report on how COBIT has been used in organisations. The findings from content analysis of extensive printed resources carried out on three occasions between 2003 and 2006 suggest that very few academically‐focused evaluations of COBIT implementations have been undertaken, despite COBIT's extensive use in organisations throughout the world. Analysis points to growing acceptance of COBIT by both academics and practitioners, as well as a maturation in practitioner discussion of the framework. However, considerable potential exists for academic research that evaluates COBIT's effectiveness, to determine COBIT's value for organisations.
Kinetics of Individual Nucleation Events Observed in Nanoscale Vapor-Liquid-Solid Growth
Authors: Kim B. J. , Tersoff J. , Kodambaka S. , Reuter M. C. , Stach E. A. , Ross F. M.
Published: November 2008

We measured the nucleation and growth kinetics of solid silicon (Si) from liquid gold-silicon (AuSi) catalyst particles as the Si supersaturation increased, which is the first step of the vapor-liquid-solid growth of nanowires. Quantitative measurements agree well with a kinetic model, providing a unified picture of the growth process. Nucleation is heterogeneous, occurring consistently at the edge of the AuSi droplet, yet it is intrinsic and highly reproducible. We studied the critical supersaturation required for nucleation and found no observable size effects, even for systems down to 12 nanometers in diameter. For applications in nanoscale technology, the reproducibility is essential, heterogeneity promises greater control of nucleation, and the absence of strong size effects simplifies process design.
A Female
Homo erectus
Pelvis from Gona, Ethiopia
Authors: Simpson Scott W. , Quade Jay , Levin Naomi E. , Butler Robert , Dupont-Nivet Guillaume , Everett Melanie , Semaw Sileshi
Published: November 2008

Analyses of the KNM-WT 15000
Homo erectus
juvenile male partial skeleton from Kenya concluded that this species had a tall thin body shape due to specialized locomotor and climatic adaptations. Moreover, it was concluded that
H. erectus
pelves were obstetrically restricted to birthing a small-brained altricial neonate. Here we describe a nearly complete early Pleistocene adult female
H. erectus
pelvis from the Busidima Formation of Gona, Afar, Ethiopia. This obstetrically capacious pelvis demonstrates that pelvic shape in
H. erectus
was evolving in response to increasing fetal brain size. This pelvis indicates that neither adaptations to tropical environments nor endurance running were primary selective factors in determining pelvis morphology in
H. erectus
during the early Pleistocene.
Regulatory Genes Control a Key Morphological and Ecological Trait Transferred Between Species
Authors: Kim Minsung , Cui Min-Long , Cubas Pilar , Gillies Amanda , Lee Karen , Chapman Mark A. , Abbott Richard J. , Coen Enrico
Published: November 2008

Hybridization between species can lead to introgression of genes from one species to another, providing a potential mechanism for preserving and recombining key traits during evolution. To determine the molecular basis of such transfers, we analyzed a natural polymorphism for flower-head development in
Senecio.
We show that the polymorphism arose by introgression of a cluster of regulatory genes, the
RAY
locus, from the diploid species
S. squalidus
into the tetraploid
S. vulgaris.
The
RAY
genes are expressed in the peripheral regions of the inflorescence meristem, where they promote flower asymmetry and lead to an increase in the rate of outcrossing. Our results highlight how key morphological and ecological traits controlled by regulatory genes may be gained, lost, and regained during evolution.
Observing the Creation of Electronic Feshbach Resonances in Soft X-ray–Induced O
2
Dissociation
Authors: Sandhu Arvinder S. , Gagnon Etienne , Santra Robin , Sharma Vandana , Li Wen , Ho Phay , Ranitovic Predrag , Cocke C. Lewis , Murnane Margaret M. , Kapteyn Henry C.
Published: November 2008

When an atom or molecule is ionized by an x-ray, highly excited states can be created that then decay, or autoionize, by ejecting a second electron from the ion. We found that autoionization after soft x-ray photoionization of molecular oxygen follows a complex multistep process. By interrupting the autoionization process with a short laser pulse, we showed that autoionization cannot occur until the internuclear separation of the fragments is greater than approximately 30 angstroms. As the ion and excited neutral atom separated, we directly observed the transformation of electronically bound states of the molecular ion into Feshbach resonances of the neutral oxygen atom that are characterized by both positive and negative binding energies. States with negative binding energies have not previously been predicted or observed in neutral atoms.
Genomic Loss of microRNA-101 Leads to Overexpression of Histone Methyltransferase EZH2 in Cancer
Authors: Varambally Sooryanarayana , Cao Qi , Mani Ram-Shankar , Shankar Sunita , Wang Xiaosong , Ateeq Bushra , Laxman Bharathi , Cao Xuhong , Jing Xiaojun , Ramnarayanan Kalpana , Brenner J. Chad , Yu Jindan , Kim Jung H. , Han Bo , Tan Patrick , Kumar-Sinha Chandan , Lonigro Robert J. , Palanisamy Nallasivam , Maher Christopher A. , Chinnaiyan Arul M.
Published: November 2008

Enhancer of zeste homolog 2 (EZH2) is a mammalian histone methyltransferase that contributes to the epigenetic silencing of target genes and regulates the survival and metastasis of cancer cells. EZH2 is overexpressed in aggressive solid tumors by mechanisms that remain unclear. Here we show that the expression and function of EZH2 in cancer cell lines are inhibited by microRNA-101 (miR-101). Analysis of human prostate tumors revealed that miR-101 expression decreases during cancer progression, paralleling an increase in EZH2 expression. One or both of the two genomic loci encoding miR-101 were somatically lost in 37.5% of clinically localized prostate cancer cells (6 of 16) and 66.7% of metastatic disease cells (22 of 33). We propose that the genomic loss of miR-101 in cancer leads to overexpression of EZH2 and concomitant dysregulation of epigenetic pathways, resulting in cancer progression.
Conformational Changes in the Solution Structure of the Dengue Virus 5′ End in the Presence and Absence of the 3′ Untranslated Region
Authors: Polacek Charlotta , Foley Jonathan E. , Harris Eva
Published: November 2008

Dengue virus (DENV) is an ∼10.7-kb positive-sense RNA virus that circularizes via RNA-RNA interactions between sequences in the 5′ and 3′ terminal regions. Complementarity between the cyclization sequence (CS) and the upstream AUG region (UAR) has been shown to be necessary for viral replication. Here, we present the solution structure of the 5′ end of DENV type 2 in the presence and absence of the 3′ end. We demonstrate that hybridization between the 5′ and 3′ CSs is independent of the UAR while the 5′ UAR-3′ UAR hybridization is dependent upon the 5′ CS-3′ CS interaction.
Shifts in the Selection-Drift Balance Drive the Evolution and Epidemiology of Foot-and-Mouth Disease Virus
Authors: Tully Damien C. , Fares Mario A.
Published: November 2008

Foot-and-mouth disease virus (FMDV) is the causative agent of an acute vesicular disease affecting wild and domesticated animals. Despite the economic burden of the disease and all efforts to eradicate it, FMD outbreaks continue to emerge unexpectedly in developed and developing countries. Correlation of the mutational dynamics of the virus with its epidemiology remains unexplored. Analysis of 103 complete genomes representing the seven serotypes shows the important role that selection plays in the genomic evolution of viral isolates for serotypes. We identified selection and relaxed constraints due to genetic drift through analyses of synonymous sites. Finally, we investigated interactions between mutations that showed coevolving patterns and analyzed, based on protein structures, slightly deleterious and compensatory mutational dynamics. Specifically, we demonstrate that structurally exposed capsid proteins present a greater number of adaptive mutations and relaxed selection than nonstructural proteins. Such events have been magnified during the evolution of the southern African virus types (SATs). These shifts in selection-drift balance have generated the great antigenic and genetic diversity observed for SAT serotypes and that are responsible for epizootics on the continent of Africa. The high number of slightly deleterious and compensatory mutations in SAT serotypes in structural proteins is testament to such balance plasticity. The significant accumulation of these coevolving mutations in African serotypes supports their contribution in generating adaptive immune-escaping mutants and in establishing persistent infections. The reverse of this pattern in nonstructural proteins reveals the neutral fixation of mutations in the more widely spread and commonly studied Euro-Asiatic serotypes.
Structural and Functional Studies of the Promoter Element for Dengue Virus RNA Replication
Authors: Lodeiro María F. , Filomatori Claudia V. , Gamarnik Andrea V.
Published: November 2008

The 5′ untranslated region (5′UTR) of the dengue virus (DENV) genome contains two defined elements essential for viral replication. At the 5′ end, a large stem-loop (SLA) structure functions as the promoter for viral polymerase activity. Next to the SLA, there is a short stem-loop that contains a cyclization sequence known as the 5′ upstream AUG region (5′UAR). Here, we analyzed the secondary structure of the SLA in solution and the structural requirements of this element for viral replication. Using infectious DENV clones, viral replicons, and in vitro polymerase assays, we defined two helical regions, a side stem-loop, a top loop, and a U bulge within SLA as crucial elements for viral replication. The determinants for SLA-polymerase recognition were found to be common in different DENV serotypes. In addition, structural elements within the SLA required for DENV RNA replication were also conserved among different mosquito- and tick-borne flavivirus genomes, suggesting possible common strategies for polymerase-promoter recognition in flaviviruses. Furthermore, a conserved oligo(U) track present downstream of the SLA was found to modulate RNA synthesis in transfected cells. In vitro polymerase assays indicated that a sequence of at least 10 residues following the SLA, upstream of the 5′UAR, was necessary for efficient RNA synthesis using the viral 3′UTR as template.
Protein Kinase PKR Mediates the Apoptosis Induction and Growth Restriction Phenotypes of C Protein-Deficient Measles Virus
Authors: Toth Ann M. , Devaux Patricia , Cattaneo Roberto , Samuel Charles E.
Published: November 2008

The measles virus (MV) accessory proteins V and C play important roles in MV replication and pathogenesis. Infection with recombinant MV lacking either V or C causes more cell death than infection with the parental vaccine-equivalent virus (MVvac), and C-deficient virus grows poorly relative to the parental virus. Here, we show that a major effector of the C phenotype is the RNA-dependent protein kinase PKR. Using human HeLa cells stably deficient in PKR as a result of RNA interference-mediated knockdown (PKRkdcells), we demonstrated that a reduction in PKR partially rescued the growth defect of C knockout (Cko) virus but had no effect on the growth of either wild-type (WT) or V knockout (Vko) virus. Increased growth of the Ckovirus in PKRkdcells correlated with increased viral protein expression, while defective growth and decreased protein expression in PKR-sufficient cells correlated with increased phosphorylation of PKR and the α subunit of eukaryotic initiation factor 2. Furthermore, infection with WT, Vko, or especially Ckovirus caused significantly less apoptosis in PKRkdcells than in PKR-sufficient cells. Although apoptosis induced by Ckovirus infection in PKR-sufficient cells was blocked by a caspase antagonist, the growth of Ckovirus was not restored to the WT level by treatment with this pharmacologic inhibitor. Taken together, these results indicate that PKR plays an important antiviral role during MV infection but that the virus growth restriction by PKR is not dependent upon the induction of apoptosis. Furthermore, the results establish that a principal function of the MV C protein is to antagonize the proapoptotic and antiviral activities of PKR.
Severe Acute Respiratory Syndrome (SARS) Coronavirus-Induced Lung Epithelial Cytokines Exacerbate SARS Pathogenesis by Modulating Intrinsic Functions of Monocyte-Derived Macrophages and Dendritic Cells
Authors: Yoshikawa Tomoki , Hill Terence , Li Kui , Peters Clarence J. , Tseng Chien-Te K.
Published: November 2008

Severe acute respiratory syndrome (SARS), which is caused by a novel coronavirus (CoV), is a highly communicable disease with the lungs as the major pathological target. Although SARS likely stems from overexuberant host inflammatory responses, the exact mechanism leading to the detrimental outcome in patients remains unknown. Pulmonary macrophages (Mφ), airway epithelium, and dendritic cells (DC) are key cellular elements of the host innate defenses against respiratory infections. While pulmonary Mφ are situated at the luminal epithelial surface, DC reside abundantly underneath the epithelium. Such strategic locations of these cells within the airways make it relevant to investigate their likely impact on SARS pathogenesis subsequent to their interaction with infected lung epithelial cells. To study this, we established highly polarized human lung epithelial Calu-3 cells by using the Transwell culture system. Here we report that supernatants harvested from the apical and basolateral domains of infected Calu-3 cells are potent in modulating the intrinsic functions of Mφ and DC, respectively. They prompted the production of cytokines by both Mφ and DC and selectively induced CD40 and CD86 expression only on DC. However, they compromised the abilities of the DC and Mφ in priming naïve T cells and phagocytosis, respectively. We also identified interleukin-6 (IL-6) and IL-8 as key SARS-CoV-induced epithelial cytokines capable of inhibiting the T-cell-priming ability of DC. Taken together, our results provide insights into the molecular and cellular bases of the host antiviral innate immunity within the lungs that eventually lead to an exacerbated inflammatory cascades and severe tissue damage in SARS patients.
A Mechanism To Explain the Selection of the Hepatitis e Antigen-Negative Mutant during Chronic Hepatitis B Virus Infection
Authors: Frelin Lars , Wahlström Therese , Tucker Amy E. , Jones Joyce , Hughes Janice , Lee Byung O. , Billaud Jean-Noel , Peters Cory , Whitacre David , Peterson Darrell , Milich David R.
Published: November 2008

Hepatitis B virus (HBV) expresses two structural forms of the nucleoprotein, the intracellular nucleocapsid (hepatitis core antigen [HBcAg]) and the secreted nonparticulate form (hepatitis e antigen [HBeAg]). The aim of this study was to evaluate the ability of HBcAg- and HBeAg-specific genetic immunogens to induce HBc/HBeAg-specific CD4+/CD8+T-cell immune responses and the potential to induce liver injury in HBV-transgenic (Tg) mice. Both the HBcAg- and HBeAg-specific plasmids primed comparable immune responses. Both CD4+and CD8+T cells were important for priming/effector functions of HBc/HBeAg-specific cytotoxic T-lymphocyte (CTL) responses. However, a unique two-step immunization protocol was necessary to elicit maximal CTL priming. Genetic vaccination did not prime CTLs in HBe- or HBc/HBeAg-dbl-Tg mice but elicited a weak CTL response in HBcAg-Tg mice. When HBc/HBeAg-specific CTLs were adoptively transferred into HBc-, HBe-, and HBc/HBeAg-dbl-Tg mice, the durations of the liver injury and inflammation were significantly greater in HBeAg-Tg recipient mice than in HBcAg-Tg mice. Importantly, liver injury in HBc/HBeAg-dbl-Tg mice was similar to the injury observed in HBeAg-Tg mice. Loss of HBeAg synthesis commonly occurs during chronic HBV infection; however, the mechanism of selection of HBeAg-negative variants is unknown. The finding that hepatocytes expressing wild-type HBV (containing both HBcAg and HBeAg) are more susceptible to CTL-mediated clearance than hepatocytes expressing only HBcAg suggest that the HBeAg-negative variant may have a selective advantage over wild-type HBV within the livers of patients with chronic infection during an immune response and may represent a CTL escape mutant.
Vegetation and pollen relationships in eastern Canada
Authors: King George A.
Published: November 2008

The relationship between the vegetation and modern pollen assemblages in eastern Canada is summarized and analyzed using isopoll maps, ordination, and cluster analysis. The major vegetation zones are shrub tundra, forest tundra (divided into shrub and forest subzones), lichen woodland, closed black spruce forest, mixed boreal forest, and coastal barrens. The pollen assemblages of these zones are distinguished by differences in the relative abundance of a few important pollen types rather than by floristic differences. Northern zones have relatively high Cyperaceae and low Picea pollen percentages, and southern zones have high Picea and Abies pollen percentages. Surface samples from each vegetation zone generally form distinctive groups in the ordination analysis. However, samples from the shrub subzone of the forest tundra cluster with shrub tundra samples, and lichen woodland samples cluster with samples from the closed black spruce forest and the forest subzone of the forest tundra. Cluster analysis separates the samples into geographically distinct groups. However, these groups generally contain samples from several vegetation zones. The surface sample data set analyzed here will prove useful in reconstructing the vegetation history of the region. Key words: pollen surface samples, modern vegetation, eastern Canada.
Virulence dynamics and phenotypic diversity of Puccinia coronata f.sp. avenae in Canada from 1974 to 1990
Authors: Chong J. , Kolmer J. A.
Published: November 2008

The changes in virulence phenotype frequencies of Puccinia coronata Cda. f.sp. avenae Eriks. since 1974 in the eastern (Ontario, Quebec, and the Maritimes) and prairie (Manitoba and Saskatchewan) regions of Canada were examined. In the eastern region, frequency of virulence to Pc39 increased after the release of a cultivar with this resistance gene. Virulence to Pc38 and Pc39 increased in the prairie region after cultivars with these two genes were released. The frequencies of virulence to Pc35 and Pc56 fluctuated between 9 and 53% in the eastern region, even though these genes are not known to be present in oat cultivars grown there. In the prairie region, the frequencies of virulence to Pc35 and Pc40 fluctuated between 21 and 60% from 1974 to 1990, and virulence to Pc46 increased from 7% in 1974 to 72% in 1985, even though these genes have not been used in commercial oat cultivars. The prairie population generally had higher levels of phenotypic diversity, as measured by the Shannon, Simpson, and Gleason indexes, than did the eastern population in almost all years examined. These results contrast with previous studies using an older set of differentials in which the eastern population had a higher level of phenotypic diversity than the prairie population. The Rogers index indicated that differences in frequencies of virulence phenotypes between the two populations has increased gradually since 1974. Key words: crown rust, resistance genes, selection, phenotypic diversity.
Interprétation morphologique de l'embryon chez les Embryophytes, avec application au cas des Graminées (Poaceae)
Authors: Vallade Jean , Bugnon François , Ibannain Zhour
Published: November 2008

A new interpretation of the Monocotyledoneae embryo is presented following a reinvestigation of the fundamental transformations characterizing the evolution of the zygote to a plantlet, in the Archegoniatae division or Embryophyta subkingdom (including Bryophyta). The following elementary processes of embryogenesis were analysed: segmentation, territorial differentiation, histogen differentiation, and organic differentiation, the latter being related to the formation of terminal meristems. Embryos belonging to very different systematic groups are compared by a diagram showing the development of the essential parts of the embryo body. From the different data collected, a diagram is proposed to represent the embryo of the Gramineae. This includes (i) a foot area (scutellum) homologous to that of Ruppia and those of various Pteridophyta; the foot differentiation also affects a part of the rising cotyledon; (ii) a cotyledon with a coleoptilary sheath; (iii) a lateral primary caulinar meristem (shoot apex); (iv) a primary root (radicle), which is endogenous because the organic differentiation do not reach the outside of the body; (v) a coleorhiza, thallin residue of the proembryonic stage, separated from the root by a space arising from the delamination of one of the main proembryo cell walls. Key words: embryogenesis, embryo differentiation, Embryophyta, Monocotyledoneae, Gramineae.
Size-dependent reproductive and vegetative allocation in Arum italicum (Araceae)
Authors: Méndez M. , Obeso J. R.
Published: November 2008

The proportional allocation of plant total resources for growth, reproduction, vegetative propagation, and the balance between them were examined in Arum italicum. A minimum threshold dry mass (2.5 g) was found in this species before reproduction could occur, but above 10 g of dry mass, all individuals in a sample of 151 produced at least one inflorescence. Resource allocation for vegetative growth, sexual reproduction, and vegetative propagation significantly increased as dry mass of the plant increased. Increases in plant size resulted in increased proportional allocation to sexual reproduction, and relative decreases in both vegetative growth and vegetative propagation. Mass ratios between sexual reproductive structures and new tuber, and between sexual reproductive structures and organs of clonal growth increased with plant size. Allocation of resources to reproduction occurred at the expense of vegetative growth. In reproductive plants, the cost of reproduction, measured as relative reduction in vegetative growth was approximately 24% and was estimated by comparing growth in nonreproductive plants. Key words: Arum italicum, Araceae, cost of reproduction, reproductive allocation, vegetative growth, vegetative propagation.
Diversity and local distribution of mating alleles inMarasmiellus praeacutusandCollybia subnuda(Basidiomycetes, Agaricales)
Authors: Murphy John F. , Miller Jr. Orson K.
Published: November 2008

The diversity and distribution of mating alleles in local populations of two litter decomposing mushroom species were investigated. The results from mating crosses between single-spore isolates were used to deduce mating genotypes among closely adjacent individuals. Collybia subnuda has a high mating allele diversity that is comparable to the diversity of other bipolar species. Adjacent individuals of C. subnuda did not share mating alleles, which suggests that outcrossing usually occurs in this fungus. The estimate of mating allele diversity in C. subnuda is 45, with a 95% confidence interval of 19–187. A simplified approach for designing and analyzing intercollection mating crosses for tetrapolar fungi was tested with Marasmiellus praeacutus and found useful. An unexpectedly low mating allele diversity was found in M. praeacutus, with adjacent individuals frequently sharing more than one mating allele. The pattern of shared alleles in M. praeacutus suggests the occurrence of di–mon crossing (the Buller phenomenon). We suggest that the observed low level of mating allele diversity in M. praeacutus is a consequence of limited spore dispersal, and we discuss the implications of these conclusions for population sampling in the higher fungi. Key words: Collybia subnuda, Marasmiellus praeacutus, mating, population.
Temporal and spatial distribution of BN28 during low temperature acclimation of Brassica napus cv. Cascade seedlings
Authors: Beus Mitchel D. de , Johnson-Flanagan Anne M. , Boothe Joseph G.
Published: November 2008

The objective of this study was to determine the spatial and temporal distribution of the peptide BN28 in Brassica napus cv. Cascade seedlings during low temperature acclimation. Immunoblots revealed that BN28 was present in leaves and shoot apical meristems of plants grown under low temperature but was absent from older tissues in the stem. Immunocytochemistry was used to determine the distribution throughout leaf and apical meristem tissues. BN28 was found throughout the apical meristems, was localized in the ground tissue and epidermis of young leaves, and was restricted to the ground tissue and guard cells in mature leaves. Differences in total accumulation were also noted, with the youngest leaves having the highest accumulation of BN28 and the quantity decreasing with leaf age. Despite these differences, plant developmental stage did not affect the accumulation of BN28 in individual leaves. Post-transcriptional controls are expected to regulate accumulation of the protein, as bn28 mRNA accumulates during acclimation in both young and mature leaves. Immunolocalization studies of BN28 in acclimated leaf tissue confirmed that BN28 is cytoplasmically localized and has no apparent weak association with organelles or other cellular membrane systems. Key words: acclimation, Brassica, development, immunocytochemistry, low temperature, protein synthesis.
Production of a self-inhibitor of urediospore germination in Melampsora lini (flax rust) segregates as a recessive, single gene trait
Authors: Ayliffe Michael A. , Lawrence Greg J. , Ellis Jeff G. , Pryor Anthony J.
Published: November 2008

Two strains of Melampsora lini (flax rust) were identified that differed in their ability to produce a self-inhibitor of urediospore germination. Analysis of germination self-inhibitor production amongst 63 F2 progeny derived from a sexual hybrid of these two strains revealed segregation of this trait. Segregation of urediospore germination self-inhibitor production was consistent with single-locus control with inhibitor production being recessively inherited. Key words: rust, germination, spore, inhibitor.
Limitations on reproduction in alpine Ranunculus acris
Authors: Totland Ørjan
Published: November 2008

This study examines experimentally the influence of limiting factors on seed to ovule ratio and seed weight in three alpine populations of the perennial herb Ranunculus acris L. at Finse, southwest Norway. To test for pollen and resource limitation, seed production of supplementally pollinated or completely defoliated plants was compared to that of untreated plants. In one population the experiment was repeated twice during the season. In mid-season, supplemental hand-pollination had no significant effect on seed to ovule ratio, but significantly increased the seed weight, whereas complete defoliation resulted in a significant decrease in seed to ovule ratio and a marginally significant decrease in seed weight. These results indicate that pollen limitation occurred on seed weight and resource limitation mainly on seed to ovule ratio. Seed production in late-flowering control and defoliated plants in one population was nearly completely absent, whereas supplemental pollination increased seed production substantially. Most seeds were produced at the lowest elevation, and frost damage on developing seeds was most pronounced at the highest elevation population, suggesting that severe weather conditions at the highest altitudes had a negative influence on reproductive processes. Significant positive relationships between seed number and seed weight were found, possibly reflecting a large among-plant variation in total resource availability. Key words: altitude gradient, climate, defoliation, pollen and resource availability, seasonal variation, seed size.
Ecotypic differences in rhythmicity of ethylene production in Stellaria longipes: the possible roles of ACC, MACC, and ACC oxidase
Authors: Emery R. J. N. , Kathiresan A. , Reid D. M. , Chinnappa C. C.
Published: November 2008

The alpine tundra ecotype of Stellaria longipes is characterized by a dwarf phenotype, whereas the prairie ecotype can be semidwarf or highly elongated depending on its environment. Related to their ability to elongate, these ecotypes also show divergent abilities to produce and respond to ethylene. The prairie ecotype produces a strong daily rhythm of ethylene, which is maintained even following stress events such as wind. The alpine ecotype exhibits a much less pronounced rhythm but greatly increases ethylene production in response to stress. We investigated what differences in ethylene synthesis might be responsible for the ability of the prairie ecotype to produce a large and regular daily rhythm of ethylene production, which in the alpine ecotype is weaker or sometimes absent. Levels of the immediate precursor to ethylene, 1-aminocyclopropane-1-carboxylate (ACC), and its major conjugate, malonyl ACC (MACC) showed no rhythm across the course of a day. Moreover ACC levels remained stable during an entire growth cycle (21 days) in the prairie ecotype, even though ethylene is known to increase especially during periods of rapid elongation. By contrast, assays of ACC oxidase performed in vivo and in vitro showed rhythms of activity similar to those of ethylene production observed in the prairie ecotype. However, the levels of ethylene produced in the ACC oxidase assays were considerably higher than levels of ethylene normally produced by unstressed plants, and the rhythm of ACC oxidase activity was observed in both ecotypes, despite the fact that alpine Stellaria longipes exhibits a less pronounced ethylene rhythm. Thus, we concluded that although ACC oxidase activity may partially account for rhythmic production of ethylene in prairie ecotypes, other controlling factors such as spatial separation of ACC from ACC oxidase should be investigated. Key words: ACC oxidase, ecotypes, ethylene, phenotypic plasticity, rhythmicity, Stellaria longipes.
Stress-induced senescence predominates in endothelial cells isolated from atherosclerotic chronic smokers
Authors: Farhat Nada , Thorin-Trescases Nathalie , Voghel Guillaume , Villeneuve Louis , Mamarbachi Maya , Perrault Louis P. , Carrier Michel , Thorin Eric
Published: November 2008

Age-associated telomere shortening leads to replicative senescence of human endothelial cells (EC). Risk factors for cardiovascular disease (CVD) accelerate ageing, while there is a concomitant rise in oxidative stress known to promote stress-induced senescence (SIS) in vitro. Of all risk factors for CVD, smoking is most associated with the development of inflammation and accelerated atherosclerosis due to a prooxidant–antioxidant imbalance. We tested the hypothesis that SIS predominates in EC isolated from chronic smokers with premature atherosclerosis undergoing coronary artery bypass graft surgery (CABG). We isolated and cultured EC from segments of internal mammary arteries from smoker, former smoker, and nonsmoker coronary patients. Senescence of EC was induced by serial passage and quantified by the measurement of telomere length and senescence-associated β-galactosidase activity. Compared with nonsmokers, smoker patients were 10 years younger at the time of CABG, evidence of premature atherosclerosis. Cellular senescence was independent of telomere length and directly related to oxidative damage. EC exhibited higher expression levels of markers of oxidative stress (lipid peroxydation level and caveolin-1 mRNA), inflammation (angiopoietin-like 2 mRNA), hypoxia (vascular endothelial growth factor (VEGF)-A mRNA), and cell damage (p53 mRNA). In conclusion, a high oxidative stress environment in EC isolated from atherosclerotic chronic smokers predisposes to SIS rather than replicative senescence.
ON THE CYLINDRICAL GRAD-SHAFRANOV EQUATION
Authors: BESKIN V. S. , NOKHRINA E. E.
Published: November 2008

The goal of this paper is to pay attention to the 1D cylindrical version of the Grad-Shafranov (GS) equation. In our opinion, this approach is more rich than classical self-similar ones, and more suitable for the astrophysical jets we observe. In particular, it allows us to describe the central (and, hence, the most energetic) part of the flow.
RADIATION FROM THE INTERACTION OF MICROQUASARS WITH THE ISM
Authors: BORDAS P. , PAREDES J. M. , BOSCH-RAMON V.
Published: November 2008

Microquasars (MQs) are X-ray binary systems that display relativistic radio jets. These objects constitute a suitable laboratory for testing high energy astrophysical processes still not well understood, such as those present when jets interact with the interstellar medium (ISM). Focusing on the study of the nonthermal contribution from cocoon and bow-shock regions, we explore, under different ISM densities and ages of the jet source, the possibility to detect MQ jet termination regions. We conclude that emission from these regions may be faint, but still detectable in the radio, X-ray, and gamma-ray bands.
CLUES FOR THE COMPOSITION OF RELATIVISTIC MICROQUASAR JETS
Authors: HEINZ SEBASTIAN
Published: November 2008

We discuss the evidence for proton loading in relativistic jets from microquasars in light of recent constraints on the jet power. We argue that, both in the case of the Cygnus X-1 jet and the entire ensemble of Galactic microquasars, the evidence points towards a significant contribution to the total kinetic energy flux from cold protons. However, as with all other methods of constraining jet composition (except for the singular case of SS 433), a number of alternative, though maybe less plausible, explanations exist. In light of this continued elusiveness of a single slam-dunk argument for proton loading, the best we can hope for is a continuing accumulation of bits of evidence such as these which will, on the whole, form a preponderance of evidence against pure pair jets.
DEVELOPMENT OF A THREE-POINT SIXTH-ORDER HELMHOLTZ SCHEME
Authors: SHEU TONY W. H. , HSIEH L. W. , CHEN C. F.
Published: November 2008

A compact finite-difference scheme is presented in this paper for efficiently solving the variable Helmholtz equation. This scheme development involves relating the derivative terms, namely, uxx and uxxxx, to u at the two adjacent nodal points in order to yield a 3-point stencil implicit scheme. In addition to sixth-order accuracy, the proposed scheme can conditionally provide oscillation-free solutions using the underlying M-matrix theory. Computations have been carried out for several problems which are amenable to exact solutions. Agreement with the exact solutions is excellent even in a grid system involving fewer number of mesh points. Thus, the integrity of the compact scheme and the efficiency of the alternating direction implicit algorithm are demonstrated. The proposed scheme is applied to study the effect of variable wave number on the wave propagation characteristics for the problem, which is partly bounded by a scatter surface.
THE MATRIX FORMULATION OF BOUNDARY INTEGRAL MODELING OF ELASTIC WAVE PROPAGATION IN 2D MULTI-LAYERED MEDIA WITH IRREGULAR INTERFACES
Authors: LIU E. , DOBSON A. , PAN D. M. , YANG D. H.
Published: November 2008

A semi-analytic method based on the propagation matrix formulation of indirect boundary element method to compute response of elastic (and acoustic) waves in multi-layered media with irregular interfaces is presented. The method works recursively starting from the top-most free surface at which a stress-free boundary condition is applied, and the displacement-stress boundary conditions are then subsequently applied at each interface. The basic idea behind this method is the matrix formulation of the propagation matrix (PM) or more recently the reflectivity method as wide used in the geophysics community for the computation of synthetic seismograms in stratified media. The reflected and transmitted wave fields between arbitrary shapes of layers can be computed using the indirect boundary element (BEM) method. Like any standard BEM methods, the primary task of the BEM-based propagation matrix method (thereafter called PM–BEM) is the evaluation of element boundary integral of the Green's function, for which there are standard method that can be adapted. In addition, effective absorbing boundary conditions as used in the finite difference numerical method is adapted in our implementation to suppress the spurious arrivals from the artificial boundaries due to limited model space. To our knowledge, such implementation has not appeared in the literature. Several examples are presented in this paper to demonstrate the effectiveness of this proposed PM–BEM method for modeling elastic waves in media with complex structure.
SIMULATION OF INCIDENT NONLINEAR SOUND BEAM AND 3D SCATTERING FROM COMPLEX TARGETS
Authors: RUDD KEVIN , HINDERS MARK
Published: November 2008

This paper presents an integrated simulation method for investigating nonlinear sound beams and three-dimensional (3D) acoustic scattering from any combination of complicated objects. A standard finite-difference simulation method is used to model pulsed nonlinear sound propagation from a source to a scattering target via the Khokhlov–Zabolotskaya–Kuznetsov equation. Then, a parallel 3D acoustic simulation method based on the finite integration technique is used to model the acoustic wave interaction with the target. Any combination of objects and material layers can be placed into the 3D simulation space to study the resulting interaction. Several example simulations are presented to demonstrate the simulation method and 3D visualization techniques. The combined simulation method is validated by comparing experimental and simulation data and a demonstration of how this combined simulation method assisted in the development of a nonlinear acoustic concealed weapons detector is also presented.
TELEPORTING AN ARBITRARY TWO-PARTICLE STATE VIA W OR W-LIKE STATE
Authors: HU KE-XIANG , WANG YAN-WEI , JIN BAI-QI , ZHENG YI-ZHUANG
Published: November 2008

In this paper, we present a scheme for quantum teleportation of an arbitrary two-particle state via entangled W state or W-like state channels. We find that the success of teleportation is probabilistic and the corresponding probability only relates to the smaller coefficients of the quantum channels. We further show that the quantum teleportation could achieve higher probability using W-like state as a channel than the W state.
AN OPERATIONAL ALGEBRAIC APPROACH TO QUANTUM CHANNEL CAPACITY
Authors: BELAVKIN V. P. , DAI X.
Published: November 2008

An elementary introduction into algebraic approach to unified quantum information theory and operational approach to quantum entanglement as generalized encoding is given. After introducing compound quantum state and two types of informational divergences, namely, Araki–Umegaki (a-type) and of Belavkin–Staszewski (b-type) quantum relative entropic information, this paper treats two types of quantum mutual information via entanglement and defines two types of corresponding quantum channel capacities as the supremum via the generalized encodings. It proves the additivity property of quantum channel capacities via entanglement, which extends the earlier results of Belavkin to products of arbitrary quantum channels for quantum relative entropy of any type.
MAXIMAL QUANTUM VIOLATION OF THE CGLMP INEQUALITY ON ITS BOTH SIDES
Authors: HU MING-GUANG , DENG DONG-LING , CHEN JING-LING
Published: November 2008

We investigate the maximal violations for both sides of the d-dimensional CGLMP inequality by using the Bell operator method. It turns out that the maximal violations have a decelerating increase as the dimension increases and tend to a finite value at infinity. The numerical values are given out up to d = 106 for positively maximal violations and d = 2 × 105 for negatively maximal violations. Counterintuitively, the negatively maximal violations tend to be a little stronger than the positively maximal violations. Further we show the states corresponding to these maximal violations and compare them with the maximally entangled states by utilizing entangled degree defined by von Neumann entropy. It shows that their entangled degree tends to some nonmaximal value as the dimension increases.
Regulation of liver hepcidin expression by alcohol in vivo does not involve Kupffer cell activation or TNF-α signaling
Authors: Harrison-Findik Duygu Dee , Klein Elizabeth , Evans John , Gollan John
Published: November 2008

Alcohol downregulates hepcidin expression in the liver leading to an increase in intestinal iron transport and liver iron storage. We have previously demonstrated that alcohol-mediated oxidative stress is involved in the inhibition of hepcidin transcription by alcohol in vivo. Kupffer cells and TNF-α play a key role in alcohol-induced liver injury. The aim of this study was to define their involvement in the regulation of hepcidin expression by alcohol. Kupffer cells were inactivated or depleted by employing gadolinium chloride and liposomes containing clodronate, respectively. Rats pair fed with the alcohol-Lieber-DeCarli diet for 6 wk and mice fed with 20% ethanol in the drinking water for 1 wk were used as experimental models. Interestingly, alcohol downregulated hepcidin expression in the livers of rats and mice independent of gadolinium chloride or clodronate treatment. One week of alcohol treatment was sufficient to induce a significant increase in TNF-α levels and phosphorylation of NF-κB subunit p65. The neutralization of TNF-α by specific antibodies inhibited p65 phosphorylation. However, neither the neutralization of TNF-α nor the lack of TNF-α receptor expression reversed alcohol-induced suppression of liver hepcidin expression. The level of alcohol-induced ROS in the liver was also undiminished following Kupffer cell inactivation or depletion. Our results demonstrate that alcohol-induced Kupffer cell activation and TNF-α signaling are not involved in the suppression of liver hepcidin expression by alcohol-mediated oxidative stress in vivo. Therefore, these findings suggest that alcohol acts within hepatocytes to suppress hepcidin expression and thereby influences iron homeostasis.
Internet-delivered lifestyle physical activity intervention: limited inflammation and antioxidant capacity efficacy in overweight adults
Authors: Smith Derek T. , Carr Lucas J. , Dorozynski Chris , Gomashe Chirag
Published: November 2008

Overweight and physical inactivity are associated with elevated reactive oxygen species and chronic low-grade inflammation. Exercise training studies have measured changes in systemic inflammatory and oxidative/antioxidative biomarkers but predominantly at moderate-high intensities. Few low-intensity, lifestyle-based physical activity (PA) studies have been conducted. The purpose of this study was to determine whether improvements in lifestyle-oriented PA resulting from a 16-wk Internet-delivered PA program [Active Living Every Day-Internet (ALED-I)] elicit cardioprotective improvements in measures of inflammation, oxidation, or antioxidant enzyme capacity. Forty-one men and women (age 23–62 yr) were randomized to either the ALED-I intervention [ n = 19; age = 40.4 ± 1.9 yr; body mass index (BMI) = 31.4 ± 1.1 kg/m2] or a delayed intent-to-treat control condition ( n = 22; age = 46.6 ± 1.3 yr; BMI = 31.0 ± 0.7 kg/m2). TNF-α, C-reactive protein, myeloperoxidase, superoxide dismutase, catalase, total antioxidative capacity, change in PA, and other cardiometabolic disease risk factors were measured at baseline and postintervention. The ALED-I group increased PA and decreased central adiposity without changes in the control group. There was no change in the control group for any inflammation, oxidation, or antioxidant biomarkers. TNF-α decreased ( P = 0.01) in the intervention group but was not statistically different from the control group. In conclusion, modest improvements in daily low-intensity ambulatory PA as a result of an Internet-delivered lifestyle PA intervention may be cardioprotective in sedentary and overweight adults through reductions in central adiposity and inflammation. However, the absence of favorable changes in other inflammation, oxidation, and antioxidant biomarkers highlights the need for further attention to the dose response of lifestyle-structured PA promotion strategies for health maintenance/improvement.
Differential Effects of Startle on Reaction Time for Finger and Arm Movements
Authors: Carlsen Anthony N. , Chua Romeo , Inglis J. Timothy , Sanderson David J. , Franks Ian M.
Published: November 2008

Recent studies using a reaction time (RT) task have reported that a preprogrammed response could be triggered directly by a startling acoustic stimulus (115–124 dB) presented along with the usual “go” signal. It has been suggested that details of the upcoming response could be stored subcortically and are accessible by the startle volley, directly eliciting the correct movement. However, certain muscles (e.g., intrinsic hand) are heavily dependent on cortico-motoneuronal connections and thus would not be directly subject to the subcortical startle volley in a similar way to muscles whose innervations include extensive reticular connections. In this study, 14 participants performed 75 trials in each of two tasks within a RT paradigm: an arm extension task and an index finger abduction task. In 12 trials within each task, the regular go stimulus (82 dB) was replaced with a 115-dB startling stimulus. Results showed that, in the arm task, the presence of a startle reaction led to significantly shorter latency arm movements compared with the effect of the increased stimulus intensity alone. In contrast, for the finger task, no additional decrease in RT caused by startle was observed. Taken together, these results suggest that only movements that involve muscles more strongly innervated by subcortical pathways are susceptible to response advancement by startle.
GABAAReceptors Containing Gamma1 Subunits Contribute to Inhibitory Transmission in the Central Amygdala
Authors: Esmaeili Abolghasem , Lynch Joseph W. , Sah Pankaj
Published: November 2008

γ-Aminobutyric acid (GABA) is the primary inhibitory transmitter in the mammalian brain. This inhibition is mediated by type A (GABAA) receptors that are pentameric proteins assembled from 14 different subunits. Although inhibitory synaptic transmission has been studied in the amygdala, the subunit composition of receptors present at different synapses is not well understood. In this study we examined the subunit composition of GABAAreceptors at synapses in the basolateral and central amygdala. Using receptors expressed in HEK293 cells we first determined the pharmacology of receptors of different subunit compositions. We then used this pharmacological profile to test the properties of receptors present at synapses in the central and basolateral amygdala. These results show that the GABAAreceptor subunits are differentially distributed in the amygdala. Our data indicate that in the basolateral amygdala, GABAergic synapses are likely composed of receptors that contain α2βxγ2 subunits. In the central amygdala receptors at the medial input, carrying afferents from the bed nucleus of the stria terminalis contain similar receptors, whereas in the lateral input GABA receptors likely contain γ1 subunits. These inputs arise from the intercalated cells masses, thought to be responsible for mediating extinction of conditioned fear, raising the possibility of new targets for the treatment of anxiety-related disorders.