Home About us Contact
|
Home About us Contact | ||
|
|
||
Common Way (common + way)
Selected AbstractsHigh-precision measurement of internuclear distances using solid-state NMRCONCEPTS IN MAGNETIC RESONANCE, Issue 1 2008Jae-Seung Lee Abstract Today, nuclear magnetic resonance (NMR) is among the most efficient tools in structural studies. Measurement of interatomic distances is the most common way of determining high-resolution structures of molecules using NMR techniques. In this article, we describe NMR techniques for static powder samples, based on a two-dimensional single-echo scheme, enhanced with adiabatic cross-polarization. They can significantly increase the accuracy of measuring internuclear distances and turn NMR into a high-precision crystallographic technique, complementing the X-ray, and neutron-scattering methods. Experimental examples are presented for intramolecular CN and CC distances in ,-crystalline form of glycine. © 2008 Wiley Periodicals, Inc. Concepts Magn Reson Part A 32A: 56,67, 2008. [source] Deviations in the emergence of representations: a neuroconstructivist framework for analysing developmental disordersDEVELOPMENTAL SCIENCE, Issue 1 2000Andrew Oliver A common way of studying developmental disorders is to adopt a static neuropsychological deficit approach, in which the brain is characterized in terms of a normal brain with some parts or ,modules' impaired. In this paper we outline a neuroconstructivist approach in which developmental disorders are viewed as alternative developmental trajectories in the emergence of representations within neural networks. As a concrete instantiation of the assumptions underlying this general approach, we present a number of simulations in an artificial neural network model. The representations that emerge under different architectural, input and developmental timing conditions are then analysed within a multi-dimensional state space. We explore alternative developmental trajectories in these simulations, demonstrating how initial differences in the same parameter can lead to very different outcomes, and conversely how different starting states can sometimes result in similar end states (phenotypes). We conclude that the assumptions of the neuroconstructivist approach are likely to be more appropriate for analysing developmental deviations in complex dynamic neural networks, such as the human brain. [source] Localisation and distribution of hyaluronan in normal bone marrow matrix: a novel method to evaluate impending fibrosis?EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 4 2002Gunnel Sundström Abstract: Bone marrow trephine biopsies from 30 healthy volunteers, 10 men and 20 women aged 18,60 yr were obtained for identification and localisation of hyaluronan (HYA). Fixation, decalcification and embedding were performed by two different methods, with identical results in both. For comparison bone marrow trephine biopsies from three patients with different haematological diseases and known fibrosis were studied. All bone marrow specimens were also stained for reticulin grading. HYA was found in the bone marrow specimens from healthy individuals in a pattern that was concordant with the reticulin staining, the common way of visualising bone marrow fibrosis. In bone marrow from the patients with known fibrosis the HYA and reticulin staining were both more intense and abundant. Interestingly, HYA was also found intracellularly in eosinophilic cells in normal bone marrow. HYA is a polysaccharide unique both in structural and biological properties, and in excess it may predict bone marrow fibrosis. [source] LOCAL HETEROZYGOSITY-FITNESS CORRELATIONS WITH GLOBAL POSITIVE EFFECTS ON FITNESS IN THREESPINE STICKLEBACKEVOLUTION, Issue 8 2006Mélissa Lieutenant-Gosselin Abstract The complex interactions between genetic diversity and evolution have important implications in many biological areas including conservation, speciation, and mate choice. A common way to study these interactions is to look at heterozygosity-fitness correlations (HFCs). Until recently, HFCs based on noncoding markers were believed to result primarily from global inbreeding effects. However, accumulating theoretical and empirical evidence shows that HFCs may often result from genes being linked to the markers used (local effect). Moreover, local effect HFCs could differ from global inbreeding effects in their direction and occurrence. Consequently, the investigation of the structure and consequences of local HFCs is emerging as a new important goal in evolutionary biology. In this study of a wild threespine stickleback (Gasterosteus aculeatus) population, we first tested the presence of significant positive or negative local effects of heterozygosity at 30 microsatellites loci on five fitness components: survival, mating success, territoriality, length, and body condition. Then, we evaluated the direction and shape of total impact of local HFCs, and estimated the magnitude of the impacts on fitness using regression coefficients and selection differentials. We found that multilocus heterozygosity was not a reliable estimator of individual inbreeding coefficient, which supported the relevance of single-locus based analyses. Highly significant and temporally stable local HFCs were observed. These were mainly positive, but negative effects of heterozygosity were also found. Strong and opposite effects of heterozygosity are probably present in many populations, but may be blurred in HFC analyses looking for global effects only. In this population, both negative and positive HFCs are apparently driving mate preference by females, which is likely to contribute to the maintenance of both additive and nonadditive genetic variance. [source] Modelling daily precipitation features in the Volta Basin of West AfricaINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 7 2009P. Laux Abstract The combination of a conventional Markov chain model (zero and first order) and a gamma distribution model are found to be applicable to derive meaningful agricultural features from precipitation in the Volta Basin (West Africa). Since the analysis of the monthly or annual precipitation amount does not provide any adequate information on rainfall timing and sufficiency of crop water requirement, rainfall modelling was performed on a daily time scale for 29 rainfall stations. The modelled rainfall features follow distinct spatial patterns, which will be presented as maps of(1) rainfall occurrence probabilities and (2) recommendations of optimal planting dates. In addition, the effective drought index (EDI) working on daily time scales is calculated in order to assess drought properties of five different rainfall regions within the Volta Basin. Apart from the common way of separately modelling the duration and intensity due to their different distributions, a copula approach is chosen in this study to construct a bivariate drought distribution. Application of the measures derived to agricultural decision support will be discussed briefly. Copyright © 2009 Royal Meteorological Society [source] Conversations in conservation: revealing and dealing with language differences in environmental conflictsJOURNAL OF APPLIED ECOLOGY, Issue 4 2008Thomas J. Webb Summary 1Applied ecology aims to translate research into policy recommendations. However, conflicts frequently develop if these recommendations propose a contentious course of action. A first step towards addressing such conflicts is to attempt to understand the values underpinning stakeholder viewpoints. 2We develop a computer-aided Content Analysis to analyse the language surrounding environmental conflicts for insights into stakeholder values. Using the conflict arising over proposals to cull hedgehogs Erinaceus europaeus on several Scottish islands, we show how different stakeholder groups frame the problem in different ways. 3Stakeholder groups supporting different courses of action (culling vs. translocating hedgehogs) use different arguments, the former emphasizing conservation and biodiversity, the latter focusing on animal welfare. Our method results in a graphical representation of this failure to agree on a common way to frame the issue. 4Including texts obtained from media sources illustrates how the media can exacerbate environmental conflicts through the issues they emphasize and the vocabulary they use. 5Synthesis and applications. Our method provides a simple means to quantify levels of stakeholder disagreement concerning potentially contentious environmental issues. Our results provide a starting point for the development of a quantitative, graphical tool for managers, where repeated analysis will aid in monitoring and managing conflicts. In addition, we provide a clear example of the role of societal attitudes influencing the effective implementation of ecological advice, which should encourage ecologists to become more aware of the social environment into which policy recommendations are to be launched and to ensure that their advice does not ignore important stakeholder values. [source] On Euthanasia: Blindspots in the Argument from MercyJOURNAL OF APPLIED PHILOSOPHY, Issue 2 2002Sarah Bachelard In the euthanasia debate, the argument from mercy holds that if someone is in unbearable pain and is hopelessly ill or injured, then mercy dictates that inflicting death may be morally justified. One common way of setting the stage for the argument from mercy is to draw parallels between human and animal suffering, and to suggest that insofar as we are prepared to relieve an animal's suffering by putting it out of its misery we should likewise be prepared to offer the same relief to human beings. In this paper, I will argue that the use of parallels between human and animal suffering in the argument from mercy relies upon truncated views of how the concept of a human being enters our moral thought and responsiveness. In particular, the focus on the nature and extent of the empirical similarities between human beings and animals obscures the significance for our moral lives of the kind of human fellowship which is not reducible to the shared possession of empirical capacities. I will suggest that although a critical examination of the blindspots in these arguments does not license the conclusion that euthanasia for mercy's sake is never morally permissible, it does limit the power of arguments such as those provided by Rachels and Singer to justify it. I will further suggest that examination of these blindspots helps to deepen our understanding of what is at stake in the question of euthanasia in ways that tend otherwise to remain obscured. [source] Hardening of Small Components with High-Power Diode LasersLASER TECHNIK JOURNAL, Issue 5 2010Most efficient laser source for selective changes of surface properties Hardening of metal parts is a common way to change properties of the material. Surface layer hardening processes are increasing the resistance against friction or pressure force loads. Conventional surface layer hardening processes are flame hardening or induction hardening. Hardening with a diode laser is an additional process that offers various advantages. [source] Biodegradable Polylactide and Its Nanocomposites: Opening a New Dimension for Plastics and CompositesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 14 2003Suprakas Sinha Ray Abstract The academic and industrial aspects of the preparation, characterization, mechanical and materials properties, crystallization behavior, melt rheology, and foam processing of pure polylactide (PLA) and PLA/layered silicate nanocomposites are described in this feature article. Recently, these materials have attracted considerable interest in polymer science research. PLA is linear aliphatic thermoplastic polyester and is made from agricultural products. Hectorite and montmorillonite are among the most commonly used smectite-type layered silicates for the preparation of nanocomposites. Smectites are a valuable mineral class for industrial applications because of their high cation exchange capacities, surface area, surface reactivity, adsorptive properties, and, in the case of hectorite, high viscosity, and transparency in solution. In their pristine form, they are hydrophilic in nature, and this property makes them very difficult to disperse into a polymer matrix. The most common way to overcome this difficulty is to replace interlayer cations with quaternized ammonium or phosphonium cations, preferably with long alkyl chains. In general, polymer/layered silicate nanocomposites are of three different types: (1) intercalated nanocomposites, in which insertion of polymer chains into the layered silicate structure occurs in a crystallographically regular fashion, regardless of polymer to layered silicate ratio, with a repeat distance of few nanometer; (2) flocculated nanocomposites, in which intercalated and stacked silicate layers are sometimes flocculated due to the hydroxylated edge,edge interactions between the silicate layers; (3) exfoliated nanocomposites, in which individual silicate layers are uniformly distributed in the polymer matrix by average distances that totally depend on the layered silicate loading. This new family of composite materials frequently exhibits remarkable improvements in its material properties when compared with those of virgin PLA. Improved properties can include a high storage modulus both in the solid and melt states, increased flexural properties, a decrease in gas permeability, increased heat distortion temperature, an increase in the rate of biodegradability of pure PLA, and so forth. Illustration of the biodegradability of PLA and various nanocomposites. [source] A multiphase finite element simulation of biological conversion processes in landfillsPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2009Tim Ricken Worldwide, landfills are the most common way to dispose of waste, but have an impact on the environment as a result of harmful gas and leachate production. Estimating the long-term behaviour of a landfill in regard to this gas production and organic degrading, as well as to settlement and waste water production, is of high importance. Therefore, a model has been developed to simulate these processes. This constitutive model is based on the multiphase Theory of Porous Media. The body under investigation consists of an organic and an inorganic phase as well as a liquid and a gas phase. The equations of the model are developed on the basis of a consistent thermo-mechanical approach including the momentum balance for the solid phase and the mixture, the energy balance for the mixture and the mass balance for the gas phase. All interactions between the constituents such as mass transfers, interaction forces and energy fluxes are taken into consideration. The strongly coupled set of partial differential equations is implemented in the finite element code FEAP. The theoretical framework and the results of meantime successfully performed simulation of a real landfill body will be shown. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] IV,Kant's Argument for Transcendental Idealism in the Transcendental AestheticPROCEEDINGS OF THE ARISTOTELIAN SOCIETY (HARDBACK), Issue 1pt1 2010Lucy AllaisArticle first published online: 23 APR 2010 This paper gives an interpretation of Kant's argument for transcendental idealism in the Transcendental Aesthetic. I argue against a common way of reading this argument, which sees Kant as arguing that substantive a priori claims about mind-independent reality would be unintelligible because we cannot explain the source of their justification. I argue that Kant's concern with how synthetic a priori propositions are possible is not a concern with the source of their justification, but with how they can have objects. I argue that Kant's notion of intuition needs to be understood as a kind of representation which involves the presence to consciousness of the object it represents, and that this means that a priori intuition cannot present us with a mind-independent feature of reality. [source] On the drift-flux analysis of flotation and foam fractionation processesTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 4 2008Paul Stevenson Abstract Drift-flux analyses are a common way of estimating the phase fractions and fluxes in vertical multiphase flows. However their use has had scant impact on the flotation and foam fractionation communities despite the publication of a number of such analyses over the past two decades. By recognizing that the physics that underpin the hydrodynamics of the froth are dissimilar to those that pertain to the bubbly liquid beneath, we present a drift-flux analysis with two characteristic curves. A method for obtaining the characteristic curve for the froth from experimental data for the drainage of stationary foams is presented. Les analyses de flux de dérive sont une façon commune d'estimer les fractions et flux de phase dans les écoulements polyphasiques verticaux. Toutefois, leur utilisation a eu un impact négligeable pour les problèmes de flottation et de fractionnement de mousse malgré la publication de plusieurs analyses semblables au cours des deux dernières décennies. Tout en reconnaissant que la physique sur laquelle est fondée l'hydrodynamique de l'écume diffère de celles du liquide bullant situé en dessous, nous présentons une analyse de flux de dérive avec deux courbes caractéristiques. Une méthode pour obtenir la courbe caractéristique de l'écume à partir des données expérimentales de drainage des mousses en régime stationnaire est présentée. [source] Imaging geophysical data,taking the viewer into accountARCHAEOLOGICAL PROSPECTION, Issue 1 2004T. J. Dennis Abstract A common way of presenting geophysical data from two-dimensional sources is as a grey-scale image. Some theoretical background to discrete image representation is described, and the deleterious effects of inappropriate (too sparse) sampling and display of such images discussed in an archaeological context. In high-quality images, such as magazine illustrations or digital television, the sampling densities can be sufficiently high to avoid the appearance of artefacts. Geophysical images in contrast are often sampled at very low densities; if the effective area of each sample is significantly less than the sample spacing, then the classic effect called ,aliasing' in communication engineering, caused by the violation of Nyquist's criterion, will be seen. Knowledge of the sensor's footprint can be used to select an appropriate sample density, and so minimize this source of distortion. To maximize the visibility of what may be low-contrast structures immersed in a high level of background noise, it is helpful also to consider the bandpass nature of the spatial frequency response of the human visual system. The non-linear phenomenon of visual masking is shown to influence the choice on presentation methods. Copyright © 2004 John Wiley & Sons, Ltd. [source] Analysis of genetic control elements in eukaryotes: Transcriptional activity or nuclear hitchhiking?BIOESSAYS, Issue 12 2001Muriel Zohar A common way to analyse basal and stimulated activity of eukaryotic genetic control elements, such as promoters and enhancers, is to introduce them into cells via DNA vectors containing an easily assayable reporter gene. Activity is then studied by measurement of transiently produced mRNA or reporter protein. In such assays, it is assumed that the variable measured is proportional to the transcriptional activity of the control element under investigation. Here we question the validity of this generally accepted assumption. Specifically, recent observations indicate that control elements, in addition to modulating transgene transcription, can facilitate the nuclear uptake of their carrier plasmids. This process is mediated by transcription factors or other nuclear proteins harbouring nuclear localisation signals, which bind to the control elements in the cytoplasm and transport the DNA into the nucleus through the protein nuclear import machinery. As the number of mRNA transcripts produced for an epi-chromosomally expressed transgene is directly related to its copy number inside the nucleus, such transport activity may lead to substantial overestimation of the transcriptional potency of the control element(s) studied. BioEssays 23:1176,1179, 2001. © 2001 John Wiley & Sons, Inc. [source] Inorganic Layers on Polymeric Films , Influence of Defects and Morphology on Barrier PropertiesCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 5 2003M. Hanika Abstract Flexible polymeric films are not only widely used in conventional packaging as substitute for glass and aluminum foil packaging but are also proposed as encapsulation for novel products, like flexible solar cells or organic light-emitting devices. The two essential properties of the polymeric packaging are flexibility and good permeation barrier properties against gases and vapors. This article deals with vacuum web coating as a common way of increasing barrier properties of polymeric films and the problems related to this procedure. Defects caused by particles and surface imperfections are found to dominate the permeation rate for such coated polymeric films. Atomic force microscopy, electron and also optical microscopy was used for analysis of the coating layer. Three-dimensional numerical simulations were performed for modeling of the influence of defect size, spacing and film thickness. Results of numerical modeling and of many practical experiments show that the permeability is almost independent of the substrate film thickness when a critical thickness is exceeded. In most cases the defects can be treated as independent of each other. The gas permeability of vacuum web-coated polymeric films can be quantitatively predicted by a simple formula. For gases, like oxygen, it is shown that a statistic analysis of the defect sizes by optical microscopy is sufficient. For water vapor transmission, however, the structure of the coating layer itself has also to be taken into account. [source] Learning from Difference: Considerations for Schools as CommunitiesCURRICULUM INQUIRY, Issue 3 2000Carolyn M. Shields In today's highly complex and heterogeneous public schools, the current notion of schools as homogeneous communities with shared beliefs, norms, and alues is inadequate. Drawing on Barth's (1990) question of how to use ifference as a resource, I take up ideas from feminism, multiculturalism, and inclusive education to consider the development of community in schools. I argue that despite the valuable contributions of these theoretical perspectives, each lso includes the potential for increased fragmentation and polarization. As we consider how to use differences as a foundation for community, it is important ot to reify any particular perspective, thus marginalizing others and erecting new barriers. Explicitly embracing the need to identify and respect difference, being open to new ideas without taking an exclusionary position, and committing to ongoing participation in dialogical processes may help schools to develop as more authentic communities of difference. Among the dominant issues identified in today's climate of turbulent educational reform are concerns about how to restructure schools to ensure equality of student opportunity and excellence of instruction (Elmore, 1990; Lieberman, 1992; Murphy, 1991). Many proposals include modifying present leadership and governance structures, overcoming the hegemony of existing power bases, developing mechanisms for accountability, enhancing professionalism, and co-ordinating community resources. One of the suggestions frequently made to address these issues is to change from a focus on schools as organizations to a recognition of schools as communities (Barth, 1990; Fullan, 1993; Lupart & Webber, 1996; Senge, 1990). However, despite the widespread use of the metaphor of community as an alternative to the generally accepted concept of schools as rational or functional organizations, there seems to be little clarity about the concept of community, what it might look like, how it might be implemented, or what policies might sustain it. Indeed, theories about schools as communities have often drawn from Tönnies (1887/1971) concept of gemeinschaft,a concept which perhaps evokes a more homogeneous and romanticized view of the past than one which could be helpful for improving education in today's dynamic, complex, and heterogeneous context (Beck & Kratzer, 1994; Sergiovanni, 1994a). More recently, several writers (Fine et al., 1997; Furman, 1998; Shields & Seltzer, 1997) have advanced the notion of communities of otherness or difference. These authors have suggested that rather than thinking of schools as communities that exist because of a common affiliation to an established school ethos or tradition, it might be more helpful to explore an alternative concept. A school community founded on difference would be one in which the common centre would not be taken as a given but would be co-constructed from the negotiation of disparate beliefs and values as participants learn to respect, and to listen to, each other. In this concept, bonds among members are not assumed, but forged, and boundaries are not imposed but negotiated. Over the past eight years, as I have visited and worked with a large number of schools trying earnestly to address the needs of their diverse student bodies, I have become increasingly aware of the limitations of the concept of community used in the gemeinschaft sense with its emphasis on shared values, norms, and beliefs, and have begun to reflect on the question framed by Barth (1990): ,How can we make conscious, deliberate use of differences in social class, gender, age, ability, race, and interest as resources for learning?' (p. 514). In this article, I consider how learning from three of these areas of difference: gender, race, and ability, may help us to a better understanding of educational community. This article begins with some illustrations and examples from practice, moves to consider how some theoretical perspectives may illuminate them, and concludes with reflections on how the implications of the combined reflections on practice and theory might actually help to reconceptualize and to improve practice. While it draws heavily on questions and impressions which have arisen out of much of my fieldwork, it is not intended to be an empirical paper, but a conceptual one,one which promotes reflection and discussion on the concept of schools as communities of difference. The examples of life in schools taken from longitudinal research studies in which I have been involved demonstrate several common ways in which difference is dealt with in today's schools and some of the problems inherent in these approaches. Some ideas drawn from alternative perspectives then begin to address Barth's question of how to make deliberate use of diversity as a way of thinking about community. Taken together, I hope that these ideas will be helpful in creating what I have elsewhere called ,schools as communities of difference' (Shields & Seltzer, 1997). [source] Effect of drying and storage on the degradation of total carotenoids in orange-fleshed sweetpotato cultivarsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 4 2010Aurélie Bechoff Abstract BACKGROUND: Orange-fleshed sweetpotato (OFSP) can be used to tackle vitamin A deficiency, a major public health problem in most developing countries. In East Africa, common ways of using sweetpotato include drying and subsequent storage. The aim of the study was to investigate the impact of drying and storage on the total carotenoid retention (as an estimate of provitamin A retention) from OFSP. RESULTS: Losses of total carotenoid during drying were generally low (15% or less). Total carotenoid retention in OFSP was not dependent on the type of dryer (solar or sun). Sweetpotato cultivar (Ejumula, Kakamega, SPK004/1, SPK004/1/1, SPK004/6 or SPK004/6/6) had a significant effect on retention in drying (P < 0.05). High percentage losses of total carotenoids were, however, correlated with high moisture content and high carotenoid content in fresh sweetpotato roots. After 4 months' storage at room temperature in Uganda, losses of total carotenoid in dried sweetpotato chips were high (about 70%) and this was not dependent on the use of opaque or transparent packaging. CONCLUSION: Losses of carotenoids during storage were considered to be more of a nutritional constraint to the utilisation of dried sweetpotato than losses occurring during drying. The relationship between characteristics of the cultivars and losses of carotenoids during drying should be taken into account in selection of cultivars for processing. Copyright © 2009 Society of Chemical Industry [source] Degeneracy in inventory modelsNAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 7 2002Amy Hing-Ling Lau In order-quantity reorder-point formulations for inventory items where backordering is allowed, some of the more common ways to prevent excessive stockouts in an optimal solution are to impose either a cost per unit short, a cost per stockout occasion, or a target fill rate. We show that these popular formulations, both exact and approximate, can become "degenerate" even with quite plausible parameters. By degeneracy we mean any situation in which the formulation either cannot be solved, leads to nonsensical "optimal" solutions, or becomes equivalent to something substantially simpler. We explain the reasons for the degeneracies, yielding new insight into these models, and we provide practical advice for inventory managers. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 686,705, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nav.10037 [source] | |||||||||||||||||||||||||