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Take Place (take + place)
Selected AbstractsHow Does the Trans,Cis Photoisomerization of Azobenzene Take Place in Organic Solvents?CHEMPHYSCHEM, Issue 5 2010Giustiniano Tiberio Dr. Abstract The trans,cis photoisomerization of azobenzene-containing materials is key to a number of photomechanical applications, but the actual conversion mechanism in condensed phases is still largely unknown. Herein, we study the isomerization in a vacuum and in various solvents via a modified molecular dynamics simulation adopting an ab initio torsion,inversion force field in the ground and excited states, while allowing for electronic transitions and a stochastic decay to the fundamental state. We determine the trans,cis photoisomerization quantum yield and decay times in various solvents (n -hexane, anisole, toluene, ethanol, and ethylene glycol), and obtain results comparable with experimental ones where available. A profound difference between the isomerization mechanism in vacuum and in solution is found, with the often neglected mixed torsional,inversion pathway being the most important in solvents. [source] Structural and functional changes in the olfactory pathway of adult Drosophila take place at a critical ageDEVELOPMENTAL NEUROBIOLOGY, Issue 1 2003Jean-Marc Devaud Abstract The olfactory system of several holometabolous insect species undergoes anatomical changes after eclosion of the imago, following those occurring during metamorphosis. In parallel, odor experience and learning performance also evolve with age. Here, we analyze the case of adult Drosophila females. Synaptogenesis in the antennal lobe (AL) starts in late pupa and continues during the first days of adult life, at the same time as the behavioral response to odors matures. Individual olfactory glomeruli (DM6, DM2, and V) display specific growth patterns between days 1 and 12 of adult life. Experience can modify the olfactory pathway both structurally and functionally as shown by adaptation experiments. The modifications associated with this form of nonassociative learning seem to take place at a critical age. Exposure to benzaldehyde at days 2,5 of adult life, but not at 8,11, causes behavioral adaptation as well as structural changes in DM2 and V glomeruli. Altered levels in intracellular cAMP, caused by dunce and rutabaga mutants, do not affect the normal changes in glomerular size, at least at day 6 of development, but they prevent those elicited by experience, establishing a molecular difference between glomerular changes of intrinsic versus environmental origin. Taken together, these data demonstrate an imprinting-like phenomenon in the olfactory pathway of young Drosophila adults, and illustrate its glomerulus-specific dynamics. © 2003 Wiley Periodicals, Inc. J Neurobiol 56: 13,23, 2003 [source] The zinc finger protein Gfi1 acts upstream of TNF to attenuate endotoxin-mediated inflammatory responses in the lungEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 2 2006Jianmin Jin Abstract Gfi1 is a 55-kD nuclear zinc finger protein that is differentially expressed in lymphoid and myeloid cells. Gfi1,/, mice show a very strong systemic response to the endotoxin LPS and die rapidly within 36,h with symptoms of septic shock. Here we report that the pathohysiological processes for this exaggerated inflammatory response take place in the lung. After LPS treatment, lungs of Gfi1,/, mice showed a rapid accumulation of mononuclear cells and a significant overproduction of inflammatory cytokines such as TNF, IL-1, and IL-6. Increased cytokine production was also observed in blood-free perfused lungs from Gfi1,/, mice exposed to either LPS or overventilation. Alveolar macrophages but not airway epithelial cells from Gfi1,/, mice were found to be responsible for the enhanced cytokine production. Strikingly, when the TNF gene was deleted, Gfi1,/, animals were completely rescued from LPS hypersensitivity and had significantly lower IL-1, and IL-6 levels. We conclude that the unrestrained endotoxin response of Gfi1,/, mice occurs mainly in the lung and that Gfi1 represents a novel factor limiting the inflammatory immune response of this organ, and propose that Gfi1 exerts its regulatory function in alveolar macrophages downstream of the LPS receptor (TLR4) and upstream of TNF. [source] Gene networks controlling early cerebral cortex arealizationEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2006Antonello Mallamaci Abstract Early thalamus-independent steps in the process of cortical arealization take place on the basis of information intrinsic to the cortical primordium, as proposed by Rakic in his classical protomap hypothesis [Rakic, P. (1988)Science, 241, 170,176]. These steps depend on a dense network of molecular interactions, involving genes encoding for diffusible ligands which are released around the borders of the cortical field, and transcription factor genes which are expressed in graded ways throughout this field. In recent years, several labs worldwide have put considerable effort into identifying members of this network and disentangling its topology. In this respect, a considerable amount of knowledge has accumulated and a first, provisional description of the network can be delineated. The aim of this review is to provide an organic synthesis of our current knowledge of molecular genetics of early cortical arealization, i.e. to summarise the mechanisms by which secreted ligands and graded transcription factor genes elaborate positional information and trigger the activation of distinctive area-specific morphogenetic programs. [source] Functionalized Multi-Wall Carbon Nanotubes for Lipase Immobilization,ADVANCED ENGINEERING MATERIALS, Issue 5 2010I. V. Pavlidis Abstract We examine the immobilization of lipase B from Candida antarctica on functionalized multi-wall carbon nanotubes (MWCNTs) through physical adsorption. MWCNTs functionalized with carboxyl-, amine- and ester- terminal groups on their surface are used as immobilization carriers. Dispersion of the nanotubes and the immobilization procedure take place in aqueous and low-water media. High enzyme loadings are attained, up to 25% of the weight of the carbon nanotubes. These novel biomaterials are characterized though FT-IR and Raman spectroscopy. The MWCNT,lipase bioconjugates exhibit high catalytic activity and increased storage and operational stability. The biomaterials retain more than 55% of their initial activity after 6 months at 4,°C, while they retain approximately 25% of their initial activity after 30 d of incubation in hexane at 60,°C. The catalytic behaviour of the immobilized enzyme depends on the terminal group of the carbon nanotubes, the concentration of the enzyme and the immobilization method employed. [source] Description of fatigue damage in carbon black filled natural rubberFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 12 2008J.-B. LE CAM ABSTRACT The present paper describes macroscopic fatigue damage in carbon black-filled natural rubber (CB-NR) under uniaxial loading conditions. Uniaxial tension-compression, fully relaxing uniaxial tension and non-relaxing uniaxial tension loading conditions were applied until sample failure. Results, summarized in a Haigh-like diagram, show that only one type of fatigue damage is observed for uniaxial tension-compression and fully relaxing uniaxial tension loading conditions, and that several different types of fatigue damage take place in non-relaxing uniaxial tension loading conditions. The different damage types observed under non-relaxing uniaxial tension, loading conditions are closely related to the improvement of rubber fatigue life. Therefore, as fatigue life improvement is classically supposed to be due to strain-induced crystallization (SIC), a similar conclusion can be drawn for the occurrence of different types of fatigue damage. [source] The Influence of the Parameter "Temperature" on the Abrasiveness of RockGEOMECHANICS AND TUNNELLING, Issue 1 2008Stefan Eberl cand.rer.mont. The article deals with the influence of temperature produced in the cutting process on rock abrasiveness and tool wear. Basically it was to clarify which effects take place when quartz or rock with significant quartz content is heated up to a certain temperature. Does the quartz jump from low into high quartz happening at 573 °C cause an increase in abrasiveness of mineral and rock or not? To find out, a certain number of Cerchar abrasiveness index tests were done for a detailed investigation of this topic. Additionally, to get a better understanding what really happens inside rock structure additionally other rock parameters like unconfined compressive strength, Brazilian tensile strength, ultrasonic wave velocity and density were determined on untreated and heated and subsequently cooled down rock samples. The final output of the research work showed that rocks show a very specific and significant reaction to thermal stresses induced into their structure resulting in a different behaviour regarding abrasiveness and fracturing. Einfluss des Parameters "Temperatur" auf die Abrasivität von Fels Der Artikel beschäftigt sich mit dem Einfluss der während des Schneidprozesses entstehenden Temperatur auf die Abrasivität von Gestein und auf den Verschleiß des Schneidwerkzeugs. Es sollte geklärt werden, welche Effekte auftreten, wenn Quarz und Gestein mit erheblichem Quarzgehalt bis zu einer bestimmten Temperatur erhitzt werden. Erzeugt der Quarzsprung, der bei 573 °C stattfindet, von Tiefquarz zu Hochquarz einen Anstieg in der Abrasivität von Mineralen und Gesteinen oder nicht? Um dies herauszufinden, sind eine bestimmte Anzahl von Cerchar Abrasivitätstests durchgeführt worden. Um ein besseres Verständnis zu erhalten, was wirklich in der Struktur des Gesteins passiert, sind weitere Parameter wie einachsiale Druckfestigkeit, Spaltzugfestigkeit, Ultraschallwellengeschwindigkeit und Dichte an unbehandelten und aufgeheizten und wieder abgekühlten Gesteinsproben bestimmt worden. Die Forschungsarbeit hat gezeigt, dass Gesteine eine sehr spezifische und signifikante Reaktion auf thermische Beanspruchungen ihres Gefüges zeigen, was letztlich in einem verschiedenartigen Verhalten hinsichtlich Abrasivität und Bruchverhalten zum Ausdruck kommt. [source] A history of the European Grassland Federation, 1963,2003GRASS & FORAGE SCIENCE, Issue 1 2004W. H. Prins Abstract The history of the European Grassland Federation (EGF) from its founding in 1963 to 2003 is described. The origins and constitution are described together with its membership. How the structure and functions of the EGF have changed in 40 years are outlined and the management and financial arrangements of the EGF explained. The background to Grass and Forage Science becoming the official journal of the EGF in 1996 is described. The developments that have take place in the content and size of the General Meetings and Symposia, and in their publication as Proceedings, are highlighted. The links to other organizations in grassland research and the future direction of the EGF are explored. [source] Geographies of Housing Finance: The Mortgage Market in Milan, ItalyGROWTH AND CHANGE, Issue 2 2007MANUEL B. AALBERS ABSTRACT The geography of financial exclusion has mainly focused on exclusion from retail banking. Alternatively, and following the work of David Harvey, this paper presents a geography of access to and exclusion from home mortgage finance. The case of Milan shows that capital switching to the built environment is partly a sign of economic crisis and partly a sign of the intrinsic opportunities that the built environment provides. A major factor in both is the deregulation of the mortgage market that has enabled the loosening of historically stringent lending criteria, leading to a tremendous growth of the mortgage market, while leaving the co-evolution of family and home ownership intact. In addition, capital switches within sectors of the economy and between places. In Milan, once "unattractive" but currently gentrified nineteenth-century districts underwent cycles of devalorisation and revalorisation. Even though access to mortgages has increased throughout Milan, geographical disparities in mortgage lending persist: at present, yellowlining (differential access, based on less favourable terms) is common in parts of the Milanese periphery. The creation of boundaries makes the realisation of class-monopoly rent possible; while the subsequent redrawing of these boundaries creates new submarkets in which surplus value can be extracted. Based on the Milan case, one cannot explain the timing and geography of formation and reformation of submarkets in other cities, but it helps us to see how Harvey's abstract ideas of class-monopoly rent, submarket creation, and capital switching take place in the real world. [source] Skin friction features of drilled CIP piles in sand from pile segment analysisINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 7 2008Sungjune Lee Abstract Numerical pile segment analysis is conducted in this study with an advanced soil model to investigate the skin friction behaviour of a drilled Cast-In-Place (CIP) pile installed in sand. Although the interface between the sand and pile is considered rough, thin elements adjacent to the pile are used to include effects of localized shear. Unit weights of fluid concrete and accompanied changes in stress are considered as the effects of pile installation. Changes in effective stresses are the most prominent effect due to pile installation with a change in direction of the major principal stress from the vertical to the radial direction. Shear behaviour of the sand at the interface during the early shear stage is related to the contractive tendency of the sand at small strain levels. Changes in the stress field around the pile with little changes in volumetric strain take place during the early shear stage. Stress redistributions during the early shear stage depend on the direction of the major principal stress before shear. Results of the pile segment analyses for drilled CIP piles show good agreement with design methods. Parametric studies are used to characterize the effects of sand density and pile diameter on the skin friction behaviour of drilled CIP piles. Copyright © 2007 John Wiley & Sons, Ltd. [source] Unionisation in the Dublin hotel industryINTERNATIONAL JOURNAL OF TOURISM RESEARCH, Issue 3 2003Annemarie Piso Abstract The Dublin hotel industry experiences significantly higher levels of union density than is the case amongst hotel workers in the UK. This paper examines the context in which these different experiences of union density take place. It provides an examination of the historical roots of union organisation within Dublin hotels and explores the factors that have contributed to effective organisation within the industry today. It concludes by arguing that although the structural characteristics of employment in the UK can act as a barrier to union organisation, these can, in certain historical periods, be overcome where there is a shifting balance of power between workers and employers affecting both the hotel industry and society as a whole. Copyright © 2003 John Wiley & Sons, Ltd. [source] Sacred Places, Domestic Spaces: Material Culture, Church, and Home at Our Lady of the Assumption and St. BrigittaJOURNAL FOR THE SCIENTIFIC STUDY OF RELIGION, Issue 3 2009Mary Ellen Konieczny The relationship between the material culture of public worship and congregants' homes is explored in a study of two Catholic parishes,theologically liberal St. Brigitta and conservative Our Lady of Assumption. At St. Brigitta, congregants' worship space is almost devoid of religious art and ritual objects are plain, but worshippers' homes are rich in decorative objects. By contrast, masses at Our Lady of the Assumption take place in a church filled with devotional art and ornate objects, but worshippers' homes are spare, neutrally furnished, and display few decorations. Distinct congregational logics surrounding the making of the self help to explain the material culture differences: St. Brigitta parishioners value individualized self-expression whereas Assumption's members subordinate individuality to family and church identities. Individuals use material objects not only for self-expression, but also to explicitly shape identities and make the self. [source] Neuroimaging of cortical development and brain connectivity in human newborns and animal modelsJOURNAL OF ANATOMY, Issue 4 2010Gregory A. Lodygensky Abstract Significant human brain growth occurs during the third trimester, with a doubling of whole brain volume and a fourfold increase of cortical gray matter volume. This is also the time period during which cortical folding and gyrification take place. Conditions such as intrauterine growth restriction, prematurity and cerebral white matter injury have been shown to affect brain growth including specific structures such as the hippocampus, with subsequent potentially permanent functional consequences. The use of 3D magnetic resonance imaging (MRI) and dedicated postprocessing tools to measure brain tissue volumes (cerebral cortical gray matter, white matter), surface and sulcation index can elucidate phenotypes associated with early behavior development. The use of diffusion tensor imaging can further help in assessing microstructural changes within the cerebral white matter and the establishment of brain connectivity. Finally, the use of functional MRI and resting-state functional MRI connectivity allows exploration of the impact of adverse conditions on functional brain connectivity in vivo. Results from studies using these methods have for the first time illustrated the structural impact of antenatal conditions and neonatal intensive care on the functional brain deficits observed after premature birth. In order to study the pathophysiology of these adverse conditions, MRI has also been used in conjunction with histology in animal models of injury in the immature brain. Understanding the histological substrate of brain injury seen on MRI provides new insights into the immature brain, mechanisms of injury and their imaging phenotype. [source] Indirect effects of invasive species removal devastate World Heritage IslandJOURNAL OF APPLIED ECOLOGY, Issue 1 2009Dana M. Bergstrom Summary 1Owing to the detrimental impacts of invasive alien species, their control is often a priority for conservation management. Whereas the potential for unforeseen consequences of management is recognized, their associated complexity and costs are less widely appreciated. 2We demonstrate that theoretically plausible trophic cascades associated with invasive species removal not only take place in reality, but can also result in rapid and drastic landscape-wide changes to ecosystems. 3Using a combination of population data from of an invasive herbivore, plot-scale vegetation analyses, and satellite imagery, we show how a management intervention to eradicate a mesopredator has inadvertently and rapidly precipitated landscape-wide change on sub-Antarctic Macquarie Island. This happened despite the eradication being positioned within an integrated pest management framework. Following eradication of cats Felis catus in 2001, rabbit Oryctolagus cuniculus numbers increased substantially although a control action was in place (Myxoma virus), resulting in island-wide ecosystem effects. 4Synthesis and applications. Our results highlight an important lesson for conservation agencies working to eradicate invasive species globally; that is, risk assessment of management interventions must explicitly consider and plan for their indirect effects, or face substantial subsequent costs. On Macquarie Island, the cost of further conservation action will exceed AU$24 million. [source] Computer-Mediated Communication and The Public Sphere: A Critical AnalysisJOURNAL OF COMPUTER-MEDIATED COMMUNICATION, Issue 1 2001Lincoln Dahlberg In recent times much has been said about the possibility that the two-way, decentralized communications of cyberspace can provide sites of rational-critical discourse autonomous from state and economic interests and thus extending the public sphere at large. In this paper the extent to which the Internet does in fact enhance the public sphere is evaluated. Online deliberative practices are compared with a normative model of the public sphere developed from the work of Jürgen Habermas. The evaluation proceeds at a general level, drawing upon more specific Internet research to provide a broad understanding of the democratic possibilities and limitations of the present Internet. The analysis shows that vibrant exchange of positions and rational critique does take place within many online fora. However, there are a number of factors limiting the expansion of the public sphere online. These factors include the increasing colonization of cyberspace by state and corporate interests, a deficit of reflexivity, a lack of respectful listening to others, the difficulty of verifying identity claims and information put forward, the exclusion of many from online political fora, and the domination of discourse by certain individuals and groups. The article concludes by calling for more focused Internet-democracy research to address these problems further, research for which the present paper provides a starting point. [source] Diversity patterns amongst herbivorous dinosaurs and plants during the Cretaceous: implications for hypotheses of dinosaur/angiosperm co-evolutionJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 3 2009R. J. BUTLER Abstract Palaeobiologists frequently attempt to identify examples of co-evolutionary interactions over extended geological timescales. These hypotheses are often intuitively appealing, as co-evolution is so prevalent in extant ecosystems, and are easy to formulate; however, they are much more difficult to test than their modern analogues. Among the more intriguing deep time co-evolutionary scenarios are those that relate changes in Cretaceous dinosaur faunas to the primary radiation of flowering plants. Demonstration of temporal congruence between the diversifications of co-evolving groups is necessary to establish whether co-evolution could have occurred in such cases, but is insufficient to prove whether it actually did take place. Diversity patterns do, however, provide a means for falsifying such hypotheses. We have compiled a new database of Cretaceous dinosaur and plant distributions from information in the primary literature. This is used as the basis for plotting taxonomic diversity and occurrence curves for herbivorous dinosaurs (Sauropodomorpha, Stegosauria, Ankylosauria, Ornithopoda, Ceratopsia, Pachycephalosauria and herbivorous theropods) and major groups of plants (angiosperms, Bennettitales, cycads, cycadophytes, conifers, Filicales and Ginkgoales) that co-occur in dinosaur-bearing formations. Pairwise statistical comparisons were made between various floral and faunal groups to test for any significant similarities in the shapes of their diversity curves through time. We show that, with one possible exception, diversity patterns for major groups of herbivorous dinosaurs are not positively correlated with angiosperm diversity. In other words, at the level of major clades, there is no support for any diffuse co-evolutionary relationship between herbivorous dinosaurs and flowering plants. The diversification of Late Cretaceous pachycephalosaurs (excluding the problematic taxon Stenopelix) shows a positive correlation, but this might be spuriously related to poor sampling in the Turonian,Santonian interval. Stegosauria shows a significant negative correlation with flowering plants and a significant positive correlation with the nonflowering cycadophytes (cycads, Bennettitales). This interesting pattern is worthy of further investigation, and it reflects the decline of both stegosaurs and cycadophytes during the Early Cretaceous. [source] Morphological variations in a tooth family through ontogeny in Pleurodeles waltl (Lissamphibia, Caudata)JOURNAL OF MORPHOLOGY, Issue 9 2006Tiphaine Davit-Béal Abstract Most nonmammalian species replace their teeth continuously (so-called polyphyodonty), which allows morphological and structural modifications to occur during ontogeny. We have chosen Pleurodeles waltl, a salamander easy to rear in the laboratory, as a model species to establish the morphological foundations necessary for future molecular approaches aiming to understand not only molecular processes involved in tooth development and replacement, but also their changes, notably during metamorphosis, that might usefully inform studies of modifications of tooth morphology during evolution. In order to determine when (in which developmental stage) and how (progressively or suddenly) tooth modifications take place during ontogeny, we concentrated our observations on a single tooth family, located at position I, closest to the symphysis on the left lower jaw. We monitored the development and replacement of the six first teeth in a large growth series ranging from 10-day-old embryos (tooth I1) to adult specimens (tooth I6), using light (LM), scanning (SEM), and transmission electron (TEM) microscopy. A timetable of the developmental and functional period is provided for the six teeth, and tooth development is compared in larvae and young adults. In P. waltl the first functional tooth is not replaced when the second generation tooth forms, in contrast to what occurs for the later generation teeth, leading to the presence of two functional teeth in a single position during the first 2 months of life. Larval tooth I1 shows dramatically different features when compared to adult tooth I6: a dividing zone has appeared between the dentin cone and the pedicel; the pulp cavity has enlarged, allowing accommodation of large blood vessels; the odontoblasts are well organized along the dentin surface; tubules have appeared in the dentin; and teeth have become bicuspidate. Most of these modifications take place progressively from one tooth generation to the next, but the change from monocuspid to bicuspid tooth occurs during the tooth I3 to tooth I4 transition at metamorphosis. J. Morphol. © 2006 Wiley-Liss, Inc. [source] TEMPERATURE INDUCED PHOTOINHIBITION IN OUTDOOR CULTURES OF MONODUS SUBTERRANEUSJOURNAL OF PHYCOLOGY, Issue 2000A. Vonshak Outdoor algal cultures are continuously exposed to changes in environmental conditions, particularly irradiance and temperature. While the changes in light intensity take place in a range of one to two hours, the increase in temperature is a slower process and takes about four to five hours. This de-synchronization between the two important environmental factors governing photosynthesis and growth of algae results in a unique stress condition where photoinhibition can be induced at relatively low light intensity. Outdoors the early morning culture temperature was found to be about 12 to 14° C, and reaches 25 to 28° C at mid-day. In an experiment, such a natural temperature regime was compared to another one in which the morning temperature of the culture was increased to 20° C by using a heating system. A fast decline in the maximal photochemical efficiency of PSII (Fv/Fm) was observed starting as soon as sunrise. The decline was faster in the non-heated culture and was to a lower value. The diurnal changes in the electron transfer rate (ETR) and in the non-photochemical quenching (NPQ) of the cultures, indicated that the early morning exposure of cells to sub-optimal temperature results in a fast inactivation of PSII activity which was reflected in an inhibition of the photosynthetic activity even when the two cultures finally reached the same temperature at mid-day. Thus, under the same light and temperature mid-day conditions the ETR was higher and the NPQ was significantly lower in the heated culture. Significant changes in productivity of the cultures also were observed. [source] Self-assembly and morphology of polydimethylsiloxane supramolecular thermoplastic elastomersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 12 2008Nicole E. Botterhuis Abstract Functionalization of polydimethylsiloxanes (PDMS) polymers with hydrogen-bonding ureidopyrimidinone (UPy) groups leads to supramolecular thermoplastic elastomers. In previous studies, no lateral stacking of UPy dimers was observed in UPy-functionalized polymers, unless additional urethane or urea groups were built into the hard block. However, we have shown that when PDMS is used as the soft block, this lateral aggregation of UPy dimers does take place, since long fibers could be observed in the atomic force microscopy (AFM) phase image. Also in bulk, the presence of these interactions was proven by oscillatory shear experiments. We attribute this aggregation to the incompatibility of soft block and hard block, leading to phase separation. Moreover, we have shown that additional urethane or urea groups in the hard block do lead to materials with more fibers and higher melting points. For the UPy-urea functionalized PDMS even single fibers are observed with AFM when dropcasted from a very diluted solution. When the length of the soft block is increased, the morphology changes from fibrous to spherical. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3877,3885, 2008 [source] Changing practice: The National Literacy Strategy and the politics of literacy policyLITERACY, Issue 3 2004Gemma Moss Abstract Drawing on a recent ESRC-funded research project,1 this paper will explore some of the contradictory structural features of the National Literacy Strategy (NLS), which have helped shape its evolution over time, and reflect on some of the tension points which have arisen at different levels of implementation as the Strategy unfolds. In the process, the paper will consider NLS not so much as a neutral means of transferring ,what works' from one site to another, but rather as itself constituting a new social context in which literacy teaching and learning take place. It will pay particular attention to the new pace of teaching that NLS has ushered in and the way in which this is driven by the kind of planning regime that NLS introduced. [source] On the timing characteristics of the apparent diffusion coefficient contrast in fMRIMAGNETIC RESONANCE IN MEDICINE, Issue 2 2002Stacey L. Gangstead Abstract For the past 10 years, functional MRI (fMRI) has seen rapid progress in both clinical and basic science research. Most of the imaging techniques are based on the blood oxygenation level-dependent (BOLD) contrast which arises from the field perturbation of the paramagnetic deoxyhemoglobin due to the mismatch between the local oxygen demand and delivery. Because the changes of oxygenation level take place mostly in the veins, the dominant signal sources of the BOLD signal are intra- and extravascular proton pools of the veins. Perfusion imaging methods, developed parallel to the BOLD technique, seek to quantify the blood flow and perfusion. Recently, perfusion imaging using arterial spin tagging methods have been used to study brain function by investigating the changes of the blood flow and perfusion during brain activation, thereby generating an alternative contrast mechanism to the functional brain imaging. Since most of these methods require tagging pulse and wait time for blood to be delivered to the imaged slice, the temporal resolution may not be optimal. Dynamic intravoxel incoherent motion (IVIM) weighting schemes using apparent diffusion coefficient (ADC) contrast were suggested to image the relative changes of the in-plane blood flow during brain function. In this report, it was demonstrated that, in addition to the spatial discrepancies of the activated areas, the time course based on the ADC contrast consistently precedes that from the BOLD contrast with timing offset on the order of 1 sec. Since arterial networks would have different spatial locations and preceding temporal characters, the findings in this report are indicative that the ADC contrast is sensitive to the arterial blood flow changes. Magn Reson Med 48:385,388, 2002. © 2002 Wiley-Liss, Inc. [source] Dynamic and generalized Wentzell node conditions for network equationsMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 6 2007Delio Mugnolo Abstract Motivated by a neurobiological problem, we discuss a class of diffusion problems on a network. The celebrated Rall lumped soma model for the spread of electrical potential in a dendritical tree prescribes that the common cable equation must be coupled with particular dynamic conditions in some nodes (the cell bodies, or somata). We discuss the extension of this model to the case of a whole network of neurons, where the ramification nodes can be either active (with excitatory time-dependent boundary conditions) or passive (where no dynamics take place, i.e. only Kirchhoff laws are imposed). While well-posedness of the system has already been obtained in previous works, using abstract tools based on variational methods and semigroup theory we are able to prove several qualitative properties, including asymptotic behaviour, regularity of solutions, and monotonicity of the semigroups in dependence on the physical coefficients. Copyright © 2006 John Wiley & Sons, Ltd. [source] Structural Factors Influencing Patterns of Drug Selling and Use and HIV Risk in the San Salvador Metropolitan AreaMEDICAL ANTHROPOLOGY QUARTERLY, Issue 2 2010Julia Dickson-Gomez This article explores differences in the social context in which crack sales and use and HIV risk take place in seven low-income communities in San Salvador, and structural factors that may influence these differences. The organization of drug selling varied among the communities on a number of dimensions including: whether drug sales were open or closed systems; the type of drug-selling site; and the participation of drug users in drug-distribution roles. Drug-use sites also varied according to whether crack was used in private, semiprivate, or public spaces, and whether individuals used drugs alone or with other drug users. Three patterns of drug use and selling were identified based on the dimensions outlined above. Structural factors that influenced these patterns included the geographic location of the communities, their physical layout, gang involvement in drug sales, and police surveillance. Implications for HIV risk and prevention are explored for each pattern. [source] Negotiation for Action: English Language Learning in Game-Based Virtual WorldsMODERN LANGUAGE JOURNAL, Issue 4 2009DONGPING ZHENG This study analyzes the user chat logs and other artifacts of a virtual world,,Quest Atlantis,(QA), and proposes the concept of Negotiation for Action (NfA) to explain how interaction, specifically, avatar-embodied collaboration between native English speakers and nonnative English speakers, provided resources for English language acquisition. Iterative multilayered analyses revealed several affordances of QA for language acquisition at both utterance and discourse levels. Through intercultural collaboration on solving content-based problems, participants successfully reached quest goals during which emergent identity formation and meaning making take place. The study also demonstrates that it is in this intercultural interaction that pragmatics, syntax, semantics, and discourse practices arose and were enacted. The findings are consistent with our ecological psychology framework, in that meaning emerges when language is used to coordinate in-the-moment actions. [source] Control vector parameterization approach in optimization of alternating aerobic,anoxic systemsOPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 6 2009Saziye Balku Abstract Determination of the optimal aeration profile for an activated sludge system in which nitrification and denitrification take place sequentially in a single reactor (alternating aerobic,anoxic) is an attractive optimization problem because of complexities involved in, and high computational times required for solution. The rigorous dynamic modeling and start-up simulation of such a system, together with aeration profile optimization by an evolutionary algorithm (EA), were tackled in a previous study. In this paper an easy-to-implement dynamic optimization technique based on sequential quadratic programming method and control vector parameterization approach is provided. In comparison with EA, the proposed algorithm gives better results in shorter computation times. Copyright © 2009 John Wiley & Sons, Ltd. [source] Lessons from Kipling and Rao: How to Re-Appropriate Another CultureORBIS LITERARUM, Issue 4 2002Ian Almond This brief study will examine Anglo-Indian Rudyard Kipling and Indo-Anglian Raja Rao's, attempts to re-appropriate a foreign culture in terms of their own wills. The novelist Rao's conviction of India's position as the origin of all Western culture, alongside Kipling's own curious tale of a tribe of distant "Englishmen" rediscovered in Northwest Afghanistan, both offer examples of attempts to re-describe and ultimately re-locate radically different cultures within the authors' own more familiar vocabularies. How does this cultural re-appropriation take place, and what happens to the author's parent culture when something as radically ,other' as an Afghan tribe or a medieval French heresy is suddenly and unexpectedly re-incorporated into the ,family'? The often unsettling consequences of this operation are considered as they manifest themselves in both texts in similar ways, advancing the possibility that cultural-appropriation affects the appropriator as much as the appropriated. And so strong is the inclination that is rooted in Mankind to the Love of their Country, that some learned and witty Men , have used great Art and Industry to represent them with such advantage to the World, as though Paradise were but another Name for their native Country. Bishop Stillingfleet1 [source] Correlation between radiculalgia and counts of T lymphocyte subsets in the peripheral blood of patients with lumbar disc herniationORTHOPAEDIC SURGERY, Issue 4 2009Peng Tian MD Objective:, To determine the correlation between the degree of radiculalgia and counts of T lymphocyte subsets in the peripheral blood of patients with lumbar disc herniation. Methods:, Forty-nine patients with lumbar disc herniation (group A) were divided into three subgroups according to Visual Analogue Scale (VAS) pain scores (group A1: n= 12, VAS 0,4.0; A2: n= 24, VAS 4.1,7.0; A3: n= 13, VAS 7.1,10.0. Twenty health blood donors who volunteered to be involved in the study comprised the control group (group B). Peripheral blood counts of various T lymphocyte subsets were measured in each group. Results:, (i) The counts of CD4+ T and CD4+/CD8+ lymphocytes were higher in group A than in group B, and the difference between the two groups was statistically significant (P < 0.05). There were also statistically significant differences between group A and group B in the counts of CD3+ and CD8+ T lymphocytes (P < 0.05); (ii) There was no correlation between the VAS scores and the counts of CD3+ T lymphocytes (r= 0.194, P > 0.05). A strong significant correlation was observed between the VAS scores and counts of CD4+ T lymphocytes (r= 0.542, P < 0.05), CD4+/CD8+ (r= 0.468, P < 0.05), which increased with increasing VAS scores in the three subgroups of group A (P < 0.05). However there was a significant negative linear correlation between CD8+ T lymphocyte counts and pain scores (r=,0.462, P < 0.05). Conclusion:, Our results suggest that changes in T lymphocyte subsets in peripheral blood take place after prolapse of lumbar intervertebral discs. The current results may provide support for involvement of immunologic mechanisms in low back pain secondary to herniation of the lumbar disc. T lymphocytes may play an important role in the development of symptoms in patients with lumbar intervertebral disc herniation. [source] Take If from Me: The Epistemological Status of TestimonyPHILOSOPHY AND PHENOMENOLOGICAL RESEARCH, Issue 2 2002CATHERINEZ. Testimony consists in imparting information without supplying evidence or argument to back one's claims. To what extent does testimony convey epistemic warrant? C. J. A. Coady argues, on Davidsonian grounds, that (1) most testimony is true, hence (2) most testimony supplies warrant sufficient for knowledge. I appeal to Grice's maxims to undermine Coady's argument and to show that the matter is more complicated and context-sensitive than is standardly rocognized. Informative exchanges take place within networks of shared, tacit assumptions that affect the scope and strength of our claims, and the level of warrant required for their responsible assertion. The maxims explain why different levels of warrant are transferred in different contexts. [source] A dual-sequence framework for B2C relationship formation: Moderating effects of employee communication style in online group chatPSYCHOLOGY & MARKETING, Issue 2 2009Pratibha A. Dabholkar Past research on B2C relationships has typically focused on unidimensional constructs of satisfaction, trust, and commitment, ignoring underlying psychological dimensions. Although some studies have examined cognitive and affective dimensions of these relational constructs, dual sequential effects in relationship formation have not been investigated. This study proposes and finds (in the context of online group chat) that parallel cognitive and affective sequences of relationship formation take place, thus expanding scholarly understanding of underlying psychological processes and offering marketing practitioners two different ways to build relationships with consumers. The proposed dual-sequence relational framework further advances theory by shedding light on counterintuitive findings in past research. The study also supports the proposed moderating effects of employee communication style, such that sequential effects of cognitive (affective) relational constructs are stronger with a task-oriented (socially oriented) employee, thus offering insights to practitioners in hiring and training employees to match specific organizational goals for building relationships with consumers. © 2009 Wiley Periodicals, Inc. [source] ONE FIGHT, ONE TEAM: THE 9/11 COMMISSION REPORT ON INTELLIGENCE, FRAGMENTATION AND INFORMATIONPUBLIC ADMINISTRATION, Issue 2 2006HANS DE BRUIJN In its report published in 2004, the National Commission on Terrorist Attacks Upon the United States (known as the ,9/11 Commission') analyses the functioning of the Intelligence Community (ICo). It indicates that the ICo is both over-fragmented and guilty of not sharing enough information. The Commission recommends that central control of the ICo needs to be strengthened and that more incentives for information-sharing should be designed. This article takes a critical look at these two recommendations. Sharing information carries major risks and is therefore not something that can take place as a matter of course. Moreover, information has to be subject to a selection process before it can be shared. This selection cannot be measured objectively, so mistakes in the selection are unavoidable. Strengthening central control also poses risks: it engenders more battles over territory, it does not improve understanding of the capillaries of the organization , the capillaries being where the primary processes of information gathering, validation and assessment take place , and it involves the destruction of checks and balances. Fragmentation may even be functional since it leads to redundancy, itself a safeguard against the risk of misselecting relevant information. [source] | |||||||||||||||||||||||||||||||||||||