bluuebunny/crossref_metadata_2025 huggingface dataset:
Demography of the arable weed Diplotaxis erucoides in central Catalonia, Spain
Authors: Sans F. X. , Masalles R. M.
Published: November 2008

The demographic performance of a Mediterranean annual arable weed (Diplotaxis erucoides) related to both environmental conditions and disturbance was studied in an agricultural system disturbed by ploughing at various times in the year. Comparative analysis of survival curves reveals that mortality rates are dependent on a variety of environmental conditions, namely competition with neighbouring plants, frost, and availability of water resources. The demographic response of D. erucoides may vary depending upon how the unfavourableness of the environment compares with its physiological tolerance. Under environmental conditions not exceeding its physiological tolerance, D. erucoides reacts through phenotypic plasticity. However, in arable fields where periodic mechanical disturbance removed all individuals before reproduction, or unfavourable environmental conditions such as frost and drought exceeded the physiological tolerance of D. erucoides, widespread mortality occurred. Persistence then depended on high fecundity, low emergence rates, and high year-to-year seed survival. The results of our study show that different cultivation treatments will affect the persistence of D. erucoides. Long-term high-disturbance regimes could produce a progressive decrease in numbers due to drastic reduction, even the absence, of new fresh seed shed onto the field and consequently a progressive depletion of the seed bank. Similarly, low-disturbance regimes or absence of disturbance could produce a rapid decrease in numbers related to an increase of associated species and the low competitive ability of D. erucoides. Key words: demography, survival, disturbance, Mediterranean weed, Diplotaxis erucoides.
The effects of density and salinity on shoot biomass and ion accumulation in five inland halophytic species
Authors: Keiffer Carolyn Howes , Ungar Irwin A.
Published: November 2008

Five inland halophytes, Atriplex prostrata, Hordeum jubatum, Salicornia europaea, Spergularia marina, and Suaeda calceoliformis, were grown in controlled laboratory conditions under three salinity treatments (0.5, 1.5, and 2.5% NaCl) and three density treatments (5, 15, and 30 plants∙100 cm−2) to determine the effects of salinity and density on survival, growth, and ion accumulation. The more salt sensitive species, A. prostrata and H. jubatum, had significant (P < 0.05) density-dependent mortality. Density significantly reduced biomass production for all species, except for H. jubatum in the high-salinity treatment. Succulence in Suaeda calceoliformis shoots increased in the high-salinity treatment, but H. jubatum plants were desiccated at the time of harvest. The ash, sodium, and chloride contents of shoots increased with salinity for all species. Sodium and Cl−ion contents for all species –treatment combinations were an order of magnitude higher than that of Mg2+, Ca2+, and K. Although A. prostrata, Salicornia europaea, and Suaeda calceoliformis accumulated similar levels of Na+in their shoots, Suaeda calceoliformis plants from the two higher densities in the low-salinity treatment accumulated twice as much total Na+per pot than A. prostrata, and seven times more Na+than Salicornia europaea. Based on these laboratory studies, Suaeda calceoliformis planted in densities ranging from 15 to 30 plants∙100 cm−2would accumulate more Na+from saline-contaminated soils than the other species. Key words: bioremediation, Atriplex, Hordeum, Salicornia, Spergularia, Suaeda..
Polyaxial development in homeotic flowers of three begonia cultivars
Authors: Lehmann Naida L. , Sattler Rolf
Published: November 2008

Development of staminate flowers in double-flowering Begonia semperflorens-cultorum cultivars 'Cinderella', 'Goldie Locks', and 'Lucy Lockett' was examined using epi-illumination microscopy, focussing on later stages when secondary partial floral buds formed on the floral apex. This process, switching from floral to inflorescence-like development, is an example of homeosis, the expression of inflorescence features on a floral apex. Floral development began as in a normal begonia flower with the formation of a perianth consisting of two sepals and two petals, but sepaloid and (or) petaloid appendages then developed in what corresponded to stamen positions in normal Begonia species. This was usually followed by lateral elongation, distortion of the primary floral apex, and formation of secondary partial floral buds. The pattern of primordial inception on the secondary apices tended to be irregular, but in some cases, appendage primordia formed in groups of twos, threes, and fours, and in a somewhat alternating formation on the apices. Often, primordial initiation seemed to continue on secondary apices even after anthesis of the staminate flower. Appendage primordia that formed on the secondary buds usually were laterally elongate and bifacial, giving them a phyllomic appearance. Others were, on occasion, more hemispherical at inception, but as they developed they became phyllomic. Key words: homeosis, polyaxial, floral development, intermediate inflorescence.
Antifungal activity of anacardic acid, a naturally occurring derivative of salicylic acid
Authors: Prithiviraj B. , Singh U. P. , Manickam M. , Ray A. B.
Published: November 2008

The antifungal activity of anacardic acid and two of its derivatives was tested against some plant pathogenic fungi and the inhibitory effect was compared with that of salicylic acid. Anacardic acid was found to be most effective and it inhibited Colletotrichum capsici spore germination at 125–150 μg mL−1. The results suggest that salicylic acid with appropriate structural modifications may prove to be a superior antifungal agent and can be utilized in controlling certain plant diseases under field conditions. Key words: salicylic acid derivatives, antifungal activity, fungal spore germination.
The autumn communities of freshwater hyphomycetes in the tributaries of the River Neelum
Authors: Bareen Firdaus-e- , Iqbal S. H.
Published: November 2008

Freshwater hyphomycete communities of autumn, based on data generated by three techniques used simultaneously, were richer than those detected by these techniques used singly. The fungal communities in the acidic streams were poorer (28–32 species) than in the circumneutral streams (39–64 species). No significant correlation was found between number of fungal species and pH of the stream water. Combining the data from this study with those of studies by other authors using the same techniques, linear correlation and regression analyses revealed the significant negative correlation between species composition of communities in a stream and its pH. The number of fungal species in assemblages detected by different techniques used singly (e.g., filtration of stream water or examination of foam concentrate) or communities based on data generated by these techniques used simultaneously versus pH values formed a unimodal curve with a maximum at a pH between 6 and 7, mostly at 6.7. The conidial dynamics were influenced by the riparian vegetation. Conidium production from submerged deciduous and conifer litter was determined under laboratory conditions. Generally conidium production per disc was higher for Anguillospora longissima (Sacc. & Syd) Ingold, Flagellospora cumula Ingold, Lunulospora curvula Ingold, and Tetracladium marchalianum de Wildeman in deciduous leaves than conifer leaves. Heliscus lugdunensis Sacc. & Therry, Alatospora acuminata Ingold, and Articulospora tetracladia Ingold produced more conidia per disc in conifer than in deciduous leaves. Percentage similarity between spora produced by submerged substrate and stream spora was higher for deciduous substratum than for coniferous substratum in five circumneutral streams with a riparian vegetation dominated by deciduous trees. This index was higher for coniferous substratum in three acidic streams in which coniferous and deciduous trees were evenly distributed. The fungal communities in the Nosehri, Pathika, and Jabbar Camp streams showed higher values of species diversity than in other streams. Key words: freshwater, hyphomycetes, species diversity.
The ultrastructure of the attack of Pinus radiata mild compression wood by erosion and tunnelling bacteria
Authors: Singh Adya P.
Published: November 2008

An inspection of 12-year-old, copper–chrome–arsenate (CCA) treated Pinus radiata wood from an industrial cooling tower showed extensive surface decay of wood. Electron microscopic examination of decaying mild compression wood indicated that compression wood cells were attacked exclusively by bacteria, which were of erosion and tunnelling types. The highly lignified outer S2 wall and the middle lamellae in the compression wood tracheids were resistant to erosion bacteria, and were only occasionally attacked by tunnelling bacteria. These observations are discussed in relation to the information available on the structure and chemical composition of compression wood. Key words: compression wood, bacterial attacks, CCA-treated wood, Pinus radiata wood, erosion bacteria, tunnelling bacteria.
In vitro expression of resistance responses to Seiridium species in micropropagated shoots of Cupressus sempervirens and Chamaecyparis lawsoniana
Authors: Spanos K. A. , Pirrie A. , Woodward S.
Published: November 2008

Wounded and nonwounded micropropagated shoots of Cupressus sempervirens and Chamaecyparis lawsoniana were inoculated in vitro with the canker-causing pathogens Seiridium cardinale (Wag.) Sutton & Gibson, Seiridium cupressi (Guba) Boeswinkel and Seiridium unicorne (Cke & Ell.) Sutton. Seiridium cardinale was significantly more pathogenic on Cupressus sempervirens than on Chamaecyparis lawsoniana (Murr.) Parlatore, irrespective of the presence of wounds on the shoots. On wounded shoots, both S. cupressi and S. unicorne caused significantly larger lesions on Chamaecyparis lawsoniana than on Cupressus sempervirens by 20 days after inoculation. Superficial wounding of shoots prior to inoculation caused a significant increase in the lengths of lesions and numbers of shoots girdled by the pathogens on both hosts. These results broadly correlate with known virulence of the three pathogens on these two host tree species in field and glasshouse tests. Using histological methods, penetration of fungal hyphae through stomatal pores of both shoots and leaves into the substomatal cavity and the mesophyll space was observed. Penetration directly through the cuticle was also seen. Defence-related responses, including accumulation of oxidized polyphenols compounds and deposition of lignin and suberin in cell walls, were detected in inoculated tissues. These responses occurred predominantly in the epidermis, including stomatal guard cells, and the hypodermis and were particularly marked in Chamaecyparis lawsoniana inoculated with S. cardinale. The possible utility of these methods in the study and detection of host genotypes resistant to Seiridium spp. is discussed. Key words: Seiridium, Cupressus, Chamaecyparis, micropropagation, in vitro inoculation, defence.
Ultrastructure and cytochemistry of early stages of colonization by Gremmeniella abietina in Pinus resinosa seedlings
Authors: Ylimartimo A. , Laflamme G. , Simard M. , Rioux D.
Published: November 2008

This paper provides details on the infection processes at the ultrastructural level in Pinus resinosa Ait. seedlings during early stages of colonization by Gremmeniella abietina (Lagerb.) Morelot. Different gold-conjugated enzymes and antibodies were used to cytochemically localize cellulose, pectin, fungal laccase, and the pathogen cells in host tissues. Gremmeniella abietina penetrated into the host through stomata of the short shoot bracts and sparsely colonized both intercellular and intracellular areas of the bract tissues. The colonizing hyphae usually had a thick wall surrounded by an extracellular sheath composed of fibrillar material. Microhyphaelike cells were observed as having penetrated host cell walls. The fungal cells (except the extracellular sheath), even when embedded in cellulosic or pectic material of host tissues, did not appear to contain cellulose or pectin. We suggest that G. abietina is able to degrade cellulose and pectin and that phenoloxidases secreted by the pathogen could be involved in host cell wall degradation. The results indicate that the extracellular sheath of G. abietina is implicated in host–pathogen interactions such as attachment of hyphae to the host surface and cell wall degradation during colonization of host tissues. Key words: Gremmeniella, Pinus, infection processes, cell wall degradation, extracellular fungal sheath, gold labelling.
High performance liquid chromatography of phenolics in recent and subfossil lichens
Authors: Fahselt Dianne , Alstrup Vagn
Published: November 2008

Subfossils of the lichens Umbilicaria krascheninnikovii (Sav.) Zahlbr. and Umbilicaria hyperborea (Ach.) Hoffm. were discovered after they were exposed by ice melt in Greenland. Extracellular phenolic substances of emerging lichens were analyzed by high performance liquid chromatography and compared with those found in lichens of the same species that escaped glaciation. All major and minor phenolics of living lichens were present in subfossils, although significantly lower amounts of the major constituent, gyrophoric acid, were documented. After being subjected to experimental pressure treatments in a hydraulic press, Umbilicaria mammulata (Ach.) Tuck, thalli showed highly significant reductions in the levels of both gyrophoric acid and lecanoric acid, and the decrease was more pronounced under the more severe of two pressure treatments. The decrease in mean phenolic content following immersion in water for 5 days was not statistically significant. There was a considerable range of phenolic concentrations among thalli of modern arctic specimens of Umbilicaria as well as among thalli recently released from ice, and the variance in subfossils was not significantly different from that in living populations. Key words: tridepsides, subfossils, Umbilicaria, pressure, glaciers, high performance liquid chromatography.
Morphological variation in sexual and agamospermous Amelanchier (Rosaceae)
Authors: Campbell Christopher S. , Wright Wesley A. , Vining Thomas F. , Halteman William A.
Published: November 2008

Agamospermy, which is almost always associated with polyploidy, is often assumed to reduce variation and foster evolution of microspecies. We tested for the occurrence of microspecies by comparing variation of sexual Amelanchier bartramiana and facultatively agamospermous (asexually seed-producing) Amelanchier laevis. We assessed within- and among-population variation of 222 individuals from six Maine populations of each species for eight morphological variables. Mahalanobis distances between individuals and population centroids and between population centroids and species centroids were used as measures of within- and among-population variation, respectively. Amelanchier bartramiana contains significantly more within- and among-population morphological variation than A. laevis. The two species do not differ in how they partition morphological variation within and among populations. Amelanchier laevis thus does not contain microspecies. Variation within A. laevis may be the result of sexuality, hybridization, polyploidy, and other factors. Key words: Amelanchier, agamospermy, Levene's statistic, microspecies, variation.
Coordinated cell elongation alone drives tropic bending in stems of the mushroom fruit body of Coprinus cinereus
Authors: Greening John P. , Sánchez Carmen , Moore David
Published: November 2008

During tropic bending in the stem of the mushroom fruit body of Coprinus cinereus the majority of extension occurred in the upper 20–30% of the stem. By attaching inert markers to the stem, it was shown that the outer flank of the bend initially has a faster rate of extension, although the inner flank matches this growth rate later in the response. Thus bending results from differential enhancement of growth rate rather than sustained differences. Large voids, up to 85 μm in diameter, observed in tropically bent stems showed no significant difference in number between inner and outer flanks but are implicated in bending because of their absence from unbent stems. Such voids may prevent the propagation of cracks through the stem tissue during bending. Creases at the external and lumen surfaces were also peculiar to bent stems and could represent constrictions caused by localized accumulation of stresses. Cell morphometric analysis of transverse sections of both flanks of the bend revealed no significant differences in hyphal diameter, distribution, or populations of cell types, but cells of the outer flank were four to five times longer than those of the inner. Thus, tropic bending requires only an increase in length of pre-existing inflated hyphae in the outer flank tissue. Key words: Coprinus cinereus, fungi, hyphae, tropism, differential growth.
The pollen tube activated abscission zone in the stigma of pearl millet: structural and physiological aspects
Authors: Heslop-Harrison Y. , Heslop-Harrison J. S.
Published: November 2008

Abscission of the stigmas of pearl millet (Pennisetum typhoides (Burman) Stapf et Hubbard) after pollination results from the activation of a specialized zone of tissue near the base. This abscission zone comprises a well-defined stretch of the basal column made up of thin-walled cells lacking a cuticularized epidermis. The penetration of the first few pollen tubes following a compatible pollination results in loss of turgor throughout the tissue, followed by loss of adhesion between the cells and ultimately disruption of the whole zone. Pectolytic enzymes are released concomitantly, but the cellulosic skeletons of the cells persist. Numerous calcium oxalate druses, identified cytochemically and by energy-dispersive X-ray analysis, are present in the cells of the abscission zone; these undergo dissolution after activation of the zone, while simultaneously the druse population in the stigma stump and the upper ovary wall increases. The barrier formed by the degenerating abscission zone tissues excludes pollen tubes arriving after the initial activation and prevents the penetration of pathogens such as ergot and so has a prophylactic role. We suggest that the collapsed abscission zone forms not only a physical barrier but also a chemical one. Dissolution products of the numerous calcium oxalate druses during the breakdown of the tissue are likely to raise the calcium ion concentrations beyond the optimum for pollen-tube growth, thereby preventing further penetration. Inhibited tubes swell at the tips and may show growth disorientation before arrest, responses similar to those seen in pearl millet tubes in culture when exposed to higher than normal calcium ion concentration. Key words: Pennisetum typhoides, stigma abscission, millet (pearl), calcium oxalate druses, pollen-tube inhibition, abscission.
5D SOLUTIONS TO ΛCDM UNIVERSE DERIVED FROM GLOBAL BRANE MODEL
Authors: PING YONGLI , XU LIXIN , CHANG BAORONG , LIU MOLIN , LIU HONGYA
Published: November 2008

An exact solution of brane universe is studied and the result indicates that Friedmann equations on the brane are modified with an extra term. This term can play the role of dark energy and make the universe accelerate. In order to derive the ΛCDM Universe from this global brane model, the new solutions are obtained to describe the 5D manifold.
EFFECT OF DECOHERENCE ON FIDELITY IN TELEPORTATION OF ENTANGLED COHERENT STATES
Authors: PRAKASH H. , CHANDRA N. , PRAKASH R. , SHIVANI
Published: November 2008

We consider the scheme proposed by Wang [Phys. Rev. A64 (2001) 022302] for teleporting bipartite entangled states, which is a superposition of coherent states |α,α〉 and |-α,-α〉, with our suggested modification [Phys. Rev. A75 (2007) 044305] and discuss the effect of decoherence on teleportation fidelity. We find that if no photons are counted in both final outputs, the minimum assured fidelity (MAF), which is the minimum of the fidelity for any arbitrary information), is still nonzero except for the case when there is no decoherence and the information is in even coherent state. For non-zero photon counts, MAF decreases with increase in |α|2 for low noise but in the case of high noise, it increases, attains a maximum value and then decreases with |α|2. We discuss the variation of average fidelity with |α|2 and show that it depends appreciably on the information for low values of |α|2 only.
PROBABILISTIC TELEPORTATION OF AN ARBITRARY TWO-QUBIT STATE VIA ONE-DIMENSIONAL FOUR-QUBIT CLUSTER-CLASS STATE
Authors: HAN LIAN-FANG , YUAN HAO
Published: November 2008

An explicit scheme for probabilistically teleporting an arbitrary two-qubit state is proposed by using a one-dimensional four-qubit cluster-class state as the quantum channel. In the scheme, the sender first performs two Bell state measurements (BSMs). Then with the sender's help, the receiver can reconstruct the original state probabilistically by introducing an auxiliary qubit and making appropriate unitary operations. Moreover, the total success probability and classical communication cost of the present scheme are also calculated.
ENTANGLEMENT IN ADIABATIC QUANTUM SEARCHING ALGORITHMS
Authors: WEN JIAYAN , QIU DAOWEN
Published: November 2008

Quantum entanglement is widely considered as one of the key resources for quantum-computational power. However, present interpretations of entanglement in speeding up of quantum algorithms remain far from complete. We analyze and compare the behaviors of entanglement during the adiabatic evolution of Grover's quantum search algorithms with complexity [Formula: see text] and O(1), respectively. Our results show that entanglement has a significant impact on the computational efficiency of both algorithms. That is, the greater the entanglement, the higher is the quantum computation, and vice versa. Furthermore, the correlations between entanglement and energy are discussed. It is observed that for the algorithm with complexity O(1), its entanglement degree becomes larger when the energy input into the quantum system increases, thus making the algorithm more efficient.
CONVERSION OF ENTANGLEMENT BETWEEN CONTINUOUS VARIABLE AND QUBIT SYSTEMS VIA INTERACTION
Authors: CHEN XIAO-YU , JIANG LI-ZHEN
Published: November 2008

We investigate how entanglement can be transferred between continuous variable and qubit systems. We find that a two-mode squeezed vacuum state and a continuous variable Werner state can be converted to the product states of an infinitive number of two-qubit states while keeping the entanglement. The reverse process is also possible. The proposed conversion model is theoretically viable but difficult to realize in the laboratory.
COLLECTIVE REMOTE STATE PREPARATION
Authors: AN NGUYEN BA , KIM JAEWAN
Published: November 2008

We show that any M ≥ 2 distant parties who independently share the complete classical knowledge of a secret qubit state can collectively prepare the state at another remote location. Two distinct schemes for such a task are proposed: one via a single (M + 1)-partite GHZ-type state and the other via M EPR-type pairs. Analytical expressions of the total success probability are derived explicitly for both the schemes. Of interest is the M-dependence of both the success probability and the receiver's action. We also construct simple quantum circuits for the two-qubit operators whose execution is necessary to accomplish the schemes.
MULTIPARTY REMOTE STATE PREPARATION WITH LINEAR OPTICAL ELEMENTS
Authors: XIA YAN , SONG JIE , SONG HE-SHAN , GUO JIN-LIANG
Published: November 2008

We present a linear optical protocol for multiparty remote state preparation (MRSP) in terms of optical elements. MRPS is a procedure for multiparty collaboration with each other to remote preparation of a known quantum state to a distant party. We show that it is possible to achieve unity fidelity remote preparation of the polarization state using optical elements. This protocol may be used for converging the split information at one point.
A QUANTUM SPLITTING SCHEME OF ARBITRARY TWO-QUBIT STATE USING FOUR-QUBIT CLUSTER STATE
Authors: PAN GUI-XIA , LIU YI-MIN , YIN XIAO-FENG , ZHANG WEN , ZHANG ZHAN-JUN
Published: November 2008

In this paper, we explore the channel capacity of the 4-qubit 4-term cluster state (i.e. (|0000〉 + |0011〉 + |1100〉 - |1111〉)/2) for splitting arbitrary two-qubit quantum information. After our extensive investigations, we found that 4 out of 12 possible distributions of the 4 qubits can be utilized to realize bipartite splitting. In terms of each distribution, the corresponding splitting scheme is presented and LOCCs (local operation and classical communication) are explicitly given.
Interactions between ROS and AMP kinase activity in the regulation of PGC-1α transcription in skeletal muscle cells
Authors: Irrcher Isabella , Ljubicic Vladimir , Hood David A.
Published: November 2008

Reactive oxygen species (ROS) play an important role in cellular function via the activation of signaling cascades. ROS have been shown to affect mitochondrial biogenesis, morphology, and function. Their beneficial effects are likely mediated via the upregulation of transcriptional regulators such as peroxisome proliferator-activated receptor-γ coactivator-1 protein-α (PGC-1α). However, the ROS signals that regulate PGC-1α transcription in skeletal muscle are not understood. Here we examined the effect of H2O2 on the regulation of PGC-1α expression, and its relationship to AMPK activation. We demonstrate that 24 h of exogenous H2O2 treatment increased PGC-1α promoter activity and mRNA expression. Both effects were blocked with the addition of N-acetylcysteine, a ROS scavenger. These effects were mediated, in part, via upstream stimulatory factor-1/Ebox DNA binding and involved 1) interactions with downstream sequences and 2) the activation of AMPK. Elevated ROS led to the activation of AMPK, likely via a decline in ATP levels. The activation of AMPK using 5-aminoimidazole-4-carboxamide-1-β- d-ribofuranoside increased PGC-1α promoter activity and mRNA levels but reduced ROS production. Thus the net effect of AMPK activation on PGC-1α expression was a result of increased transcriptional activation, counterbalanced by reduced ROS production. The effects of H2O2 on PGC-1α expression differed depending on the level of ROS within the cell. Low levels of ROS result in reduced PGC-1α mRNA in the absence of an effect on PGC-1α promoter activation. In contrast, elevated levels of H2O2 induce PGC-1α transcription indirectly, via AMPK activation. These data identify unique interactions between ROS and AMPK activation on the expression of PGC-1α in muscle cells.
Increased extracellular pressure enhances cancer cell integrin-binding affinity through phosphorylation of β1-integrin at threonine 788/789
Authors: Craig David H. , Gayer Christopher P. , Schaubert Keri L. , Wei Yanzhang , Li Jinhua , Laouar Yasmina , Basson Marc D.
Published: November 2008

Increased extracellular pressure stimulates β1-integrin-dependent cancer cell adhesion. We asked whether pressure-induced adhesion is mediated by changes in β1-integrin binding affinity or avidity and whether these changes are phosphorylation dependent. We evaluated integrin affinity and clustering in human SW620 colon cancer cells by measuring differences in binding between soluble Arg-Gly-Asp (RGD)-Fc ligands and RGD-Fc-F(ab′)2 multimeric complexes under ambient and 15-mmHg increased pressures. Phosphorylation of β1-integrin S785 and T788/9 residues in SW620 and primary malignant colonocytes was assessed in parallel. We further used GD25-β1-integrin-null murine fibroblasts stably transfected with either wild-type β1A-integrin, S785A, TT788/9AA, or T788D mutants to investigate the role of β1-integrin site-specific phosphorylation. SW620 binding of RGD-Fc-F(ab′)2 multimeric complexes, but not soluble RGD-Fc ligands, was sensitive to integrin clustering. RGD-Fc ligand binding was significantly increased under elevated pressure, suggesting that pressure modulates β1-integrin affinity. Pressure stimulated both β1-integrin S785 and T788/9 phosphorylation. GD25-β1A-integrin wild-type and S785A cells displayed an increase in adhesion to fibronectin under elevated pressure, an effect absent in β1-integrin-null and TT788/9AA cells. T788D substitution significantly elevated basal cell adhesion but displayed no further increase under pressure. These results suggest pressure-induced cell adhesion is mediated by β1-integrin T788/9 phosphorylation-dependent changes in integrin binding affinity.
Gaze and Hand Position Effects on Finger-Movement-Related Human Brain Activation
Authors: Bédard Patrick , Sanes Jerome N.
Published: November 2008

Humans commonly use their hands to move and to interact with their environment by processing visual and proprioceptive information to determine the location of a goal-object and the initial hand position. It remains elusive, however, how the human brain fully uses this sensory information to generate accurate movements. In monkeys, it appears that frontal and parietal areas use and combine gaze and hand signals to generate movements, whereas in humans, prior work has separately assessed how the brain uses these two signals. Here we investigated whether and how the human brain integrates gaze orientation and hand position during simple visually triggered finger tapping. We hypothesized that parietal, frontal, and subcortical regions involved in movement production would also exhibit modulation of movement-related activation as a function of gaze and hand positions. We used functional MRI to measure brain activation while healthy young adults performed a visually cued finger movement and fixed gaze at each of three locations and held the arm in two different configurations. We found several areas that exhibited activation related to a mixture of these hand and gaze positions; these included the sensory-motor cortex, supramarginal gyrus, superior parietal lobule, superior frontal gyrus, anterior cingulate, and left cerebellum. We also found regions within the left insula, left cuneus, left midcingulate gyrus, left putamen, and right tempo-occipital junction with activation driven only by gaze orientation. Finally, clusters with hand position effects were found in the cerebellum bilaterally. Our results indicate that these areas integrate at least two signals to perform visual-motor actions and that these could be used to subserve sensory-motor transformations.
Topography and Response Timing of Intact Cerebellum Stained With Absorbance Voltage-Sensitive Dye
Authors: Brown Michael E. , Ariel Michael
Published: November 2008

Physiological activity of the turtle cerebellar cortex (Cb), maintained in vitro, was recorded during microstimulation of inferior olive (IO). Previous single-electrode responses to such stimulation showed similar latencies across a limited region of Cb, yet those recordings lacked spatial and temporal resolution and the recording depth was variable. The topography and timing of those responses were reexamined using photodiode optical recordings. Because turtle Cb is thin and unfoliated, its entire surface can be stained by a voltage-sensitive dye and transilluminated to measure changes in its local absorbance. Microstimulation of the IO evoked widespread depolarization from the rostral to the caudal edge of the contralateral Cb. The time course of responses measured at a single photodiode matched that of single-microelectrode responses in the corresponding Cb locus. The largest and most readily evoked response was a sagittal band centered about 0.7 mm from the midline. Focal white-matter (WM) microstimulation on the ventricular surface also activated sagittal bands, whereas stimulation of adjacent granule cells evoked a radial patch of activation. In contrast, molecular-layer (ML) microstimulation evoked transverse beams of activation, centered on the rostrocaudal stimulus position, which traveled bidirectionally across the midline to the lateral edges of the Cb. A timing analysis demonstrated that both IO and WM microstimulation evoked responses with a nearly simultaneous onset along a sagittal band, whereas ML microstimulation evoked a slowly propagating wave traveling about 25 cm/s. The response similarity to IO and WM microstimulation suggests that the responses to WM microstimulation are dominated by activation of its climbing fibers. The Cb's role in the generation of precise motor control may result from these temporal and topographic differences in orthogonally oriented pathways. Optical recordings of the turtle's thin flat Cb can provide insights into that role.
Maintenance of Lateral Stability During Standing and Walking in the Cat
Authors: Karayannidou A. , Zelenin P. V. , Orlovsky G. N. , Sirota M. G. , Beloozerova I. N. , Deliagina T. G.
Published: November 2008

During free behaviors animals often experience lateral forces, such as collisions with obstacles or interactions with other animals. We studied postural reactions to lateral pulses of force (pushes) in the cat during standing and walking. During standing, a push applied to the hip region caused a lateral deviation of the caudal trunk, followed by a return to the initial position. The corrective hindlimb electromyographic (EMG) pattern included an initial wave of excitation in most extensors of the hindlimb contralateral to push and inhibition of those in the ipsilateral limb. In cats walking on a treadmill with only hindlimbs, application of force also caused lateral deviation of the caudal trunk, with subsequent return to the initial position. The type of corrective movement depended on the pulse timing relative to the step cycle. If the force was applied at the end of the stance phase of one of the limbs or during its swing phase, a lateral component appeared in the swing trajectory of this limb. The corrective step was directed either inward (when the corrective limb was ipsilateral to force application) or outward (when it was contralateral). The EMG pattern in the corrective limb was characterized by considerable modification of the hip abductor and adductor activity in the perturbed step. Thus the basic mechanisms for balance control in these two forms of behavior are different. They perform a redistribution of muscle activity between symmetrical limbs (in standing) and a reconfiguration of the base of support during a corrective lateral step (in walking).
The Response of a Stochastically Forced ENSO Model to Observed Off-Equatorial Wind Stress Forcing
Authors: McGregor Shayne , Holbrook Neil J. , Power Scott B.
Published: November 2008

This study investigates the response of a stochastically forced coupled atmosphere–ocean model of the equatorial Pacific to off-equatorial wind stress anomaly forcing. The intermediate-complexity coupled ENSO model comprises a linear, first baroclinic mode, ocean shallow water model with a steady-state, two–pressure level (250 and 750 mb) atmospheric component that has been linearized about a state of rest on the β plane. Estimates of observed equatorial region stochastic forcing are calculated from NCEP–NCAR reanalysis surface winds for the period 1950–2006 using singular value decomposition. The stochastic forcing is applied to the model both with and without off-equatorial region wind stress anomalies (i.e., poleward of 12.5° latitude). It is found that the multiyear changes in the equatorial Pacific thermocline depth “background state” induced by off-equatorial forcing can affect the amplitude of modeled sea surface temperature anomalies by up to 1°C. Moreover, off-equatorial wind stress anomalies increased the modeled amplitude of the two biggest El Niño events in the twentieth century (1982/83 and 1997/98) by more than 0.5°C, resulting in a more realistic modeled response. These equatorial changes driven by off-equatorial region wind stress anomalies are highly predictable to two years in advance and may be useful as a physical basis to enhance multiyear probabilistic predictions of ENSO indices.
Junior Partner or Empowered Community? The Role of Non-profit Social Service Providers amidst State Restructuring in the US
Authors: Trudeau Dan
Published: November 2008

Public—private partnerships have excited discussion about the possibilities of creating a more responsive welfare state in contemporary American society that empowers local communities. Sceptics see these partnerships as inherently unequal such that non-profit organisations play `junior partner' to government agencies by prioritising governments' agendas. This paper contributes to the debate by examining the role of non-profit organisations that work with government agencies to provide social services. It is argued that non-profits attempt to balance both roles—playing `junior partner' and empowering community. The experiences and practices of non-profits thus show that the role of non-profits amidst state restructuring is to negotiate the multiple obligations they have to funding agencies and local communities that seek assistance. The paper draws on a case study of non-profits providing social services to immigrant and refugee communities in Minneapolis—St Paul in order to develop the argument.
Artcetera: Narrativising Gentrification in Yorkville, Toronto
Authors: Mathews Vanessa
Published: November 2008

In this paper, the relationship is traced between art and gentrification in the neighbourhood of Yorkville, Toronto, from 1960 to 2007. Following the exodus of artists and the more experimental art galleries in the 1960s, a result of social and economic upgrading, Yorkville was forced to recast its identity, a process that involved reproducing the creative pulse of the 1960s art scene. A set of interviews conducted with visual artists who worked and/or lived in Yorkville during the 1960s is centrally located in the piece to provide a context for the shift from production to consumption. In the remainder of the paper, the role of artistic production in the gentrified landscape is examined through three examples: theming through design, art galleries and sculpture. It is argued that the relationship between art and gentrification must be extended to include the role of the non-visible in the (re)production of place identity.
Mechanisms Underlying Nationality-Based Discrimination in Teams
Authors: Schwieren Christiane , Glunk Ursula
Published: November 2008

This study examines mechanisms underlying nationality-based discrimination from two different perspectives: social psychology and microeconomics. The authors studied 91 teams in a binational setting that were offered a new team member. National composition of the team and nationality of the new member were manipulated. Overall, the study showed that discrimination based on nationality does exist in such a setting. A new member is more likely to be accepted when belonging to the majority nation represented in the team. The chances of acceptance do not increase if the newcomer belongs to the national group that is expected to perform better. Furthermore, the authors found a general tendency to close ranks when team members strongly identify with the team, when competition is high, and when success is attributed to team effort. The results underline the importance of understanding social-psychological mechanisms for explaining nationality-based discrimination in teams.
Co-evolution of Shaping Rewards and Meta-Parameters in Reinforcement Learning
Authors: Elfwing Stefan , Uchibe Eiji , Doya Kenji , Christensen Henrik I.
Published: November 2008

In this article, we explore an evolutionary approach to the optimization of potential-based shaping rewards and meta-parameters in reinforcement learning. Shaping rewards is a frequently used approach to increase the learning performance of reinforcement learning, with regards to both initial performance and convergence speed. Shaping rewards provide additional knowledge to the agent in the form of richer reward signals, which guide learning to high-rewarding states. Reinforcement learning depends critically on a few meta-parameters that modulate the learning updates or the exploration of the environment, such as the learning rate α, the discount factor of future rewards γ, and the temperature τ that controls the trade-off between exploration and exploitation in softmax action selection. We validate the proposed approach in simulation using the mountain-car task. We also transfer shaping rewards and meta-parameters, evolutionarily obtained in simulation, to hardware, using a robotic foraging task.
Securitization and the Construction of Security
Authors: McDonald Matt
Published: November 2008

Those interested in the construction of security in contemporary international politics have increasingly turned to the conceptual framework of `securitization'. This article argues that while an important and innovative contribution, the securitization framework is problematically narrow in three senses. First, the form of act constructing security is defined narrowly, with the focus on the speech of dominant actors. Second, the context of the act is defined narrowly, with the focus only on the moment of intervention. Finally, the framework of securitization is narrow in the sense that the nature of the act is defined solely in terms of the designation of threats. In outlining this critique, the article points to possibilities for developing the framework further as well as for the need for those applying it to recognize both limits of their claims and the normative implications of their analysis. I conclude by pointing to how the framework might fit within a research agenda concerned with the broader construction of security.
Commentary: Speaking in Tongues: Commentary on Cubero, de la Mata and Cubero
Authors: Zittoun Tania
Published: November 2008

Cubero, de la Mata and Cubero show that women who have attended some formal adult education are able to solve a task in a manner that suggests that they master conceptual thinking more than do women just starting such education. I suggest that this interpretation is based on models of learning that do not fully take into account the person actively engaged in making sense of the situation. Focusing on three theoretical issues—the language—thinking relationship, adult learning, and the transfer of knowledge in the test situation—I propose to reinstall an active person, and I consequently propose an alternative interpretation of the data.
The PACS and (Post-)Queer Citizenship in Contemporary Republican France
Authors: Johnston Cristina
Published: November 2008

This article examines the theoretical debates that have arisen from the development and subsequent implementation of same-sex partnership legislation in France in 1999. The significance of these debates extends far beyond the specific legislation that triggered them and can be understood as contributing to a broader analysis of the relevance of traditional French republican ideologies to the realities of contemporary, metropolitan France. The article outlines the socio-political climate against which the legislation evolved and demonstrates how its detail engages with, and challenges, key notions at the heart of French republicanism such as, for instance, the public/private division and questions of kinship, filiation, and the family. Through analysis of the writings of three key figures at the interface of sociological analysis and queer studies in France — Frédéric Martel, Eric Fassin, and Maxime Foerster — I examine how same-sex couples have come to act as figureheads for the problematic status of minority groupings more generally. Ultimately, the article seeks to examine whether this legislation can, through the dialogue and debate it has provoked, pave the way for what can be termed 'post-queer' French citizenship, a renegotiation of the relationship between queer citizens and the republic.
State Austerity and the Racial Politics of Same-Sex Marriage in the US
Authors: Kandaswamy Priya
Published: November 2008

This article situates contemporary debates about same-sex marriage in relation to the politics of state austerity, particularly 'welfare reform', in the US. While these two issues are rarely thought about together, looking at claims for marriage rights in the context of cutbacks in social welfare programs and the increasing promotion of 'marriage incentives' as a means of getting low-income single mothers off welfare reveals conservative undertones to same-sex marriage campaigns. This article examines the specific benefits that gay and lesbian activists seek to access through marriage, arguing that these benefits are better understood as privileges of a racially stratified welfare state.
Possibilities Foreclosed: The Civil Union Act and Lesbian and Gay Identity in Southern Africa
Authors: Bonthuys Elsje
Published: November 2008

In 2006 the Civil Union Act was enacted in South Africa, allowing same-sex couples to enter into marriages or civil partnerships. These relationships mirror the entry requirements and consequences of civil marriages, but contain no features of African customary marriages. This, in turn, reflects a belief that customary marriage and the African communities within which it occurs, are more traditional and conservative than civil law and that they lack the ability to accommodate same-sex relationships. This article shows that the opposite is true. Social science evidence shows that African communities in Southern Africa have long allowed same-sex marriages in a range of contexts and forms, none of which are acknowledged by the Civil Union Act. Moreover, the particular form of globalized gay and lesbian identity upon which the Act is premised, fails to reflect the more complex practices and beliefs of those who have same-sex relationships in African societies. In its insistence on merely mirroring civil marriage, the Civil Union Act therefore failed to grasp the opportunity to imagine richer concepts and more sophisticated forms of legislation which could have been inspired by the customary law.
ProICET: a cost-sensitive system for prostate cancer data
Authors: Vidrighin Camelia , Potolea Rodica
Published: November 2008

Cancer is the second most threatening disease in the world today, not only because of its mortality rate, but also due to the brutal changes it imposes on the patient's life, and the fact that its exact causes of progression remain to be discovered. Recent evolution in computer technology has resulted in the emergence of a combined approach to the diagnosis and prognosis process, with a data driven analytical approach complementing biomedical and clinical methods. Cost-sensitive learning is one such data mining method, particularly well suited for medical problems. This paper investigates the performance of a new system based on a hybrid cost-sensitive algorithm (ProICET) on a prostate cancer medical dataset, while trying to produce new medical knowledge. The target of such a system is to reduce the total cost while keeping a high classification accuracy.
Mobile technologies and the holistic management of chronic diseases
Authors: Mirza Farhaan , Norris Tony , Stockdale Rosemary
Published: November 2008

Ageing populations and unhealthy lifestyles have led to some chronic conditions such as diabetes and heart disease reaching epidemic proportions in many developed nations. This paper explores the potential of mobile technologies to improve this situation. The pervasive nature of these technologies can contribute holistically across the whole spectrum of chronic care ranging from public information access and awareness, through monitoring and treatment of chronic disease, to support for patient carers. A related study to determine the perceptions of healthcare providers to m-health confirmed the view that attitudes were likely to be more important barriers to progress than technology. A key finding concerned the importance of seamless and integrated m-health processes across the spectrum of chronic disease management.