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Many Fields (many + field)
Selected AbstractsHere is the evidence, now what is the hypothesis?BIOESSAYS, Issue 1 2004The complementary roles of inductive, hypothesis-driven science in the post-genomic era It is considered in some quarters that hypothesis-driven methods are the only valuable, reliable or significant means of scientific advance. Data-driven or ,inductive' advances in scientific knowledge are then seen as marginal, irrelevant, insecure or wrong-headed, while the development of technology,which is not of itself ,hypothesis-led' (beyond the recognition that such tools might be of value),must be seen as equally irrelevant to the hypothetico-deductive scientific agenda. We argue here that data- and technology-driven programmes are not alternatives to hypothesis-led studies in scientific knowledge discovery but are complementary and iterative partners with them. Many fields are data-rich but hypothesis-poor. Here, computational methods of data analysis, which may be automated, provide the means of generating novel hypotheses, especially in the post-genomic era. BioEssays 26:99,105, 2004. © 2003 Wiley Periodicals, Inc. [source] Large scale wildlife monitoring studies: statistical methods for design and analysisENVIRONMETRICS, Issue 2 2002Kenneth H. Pollock Abstract Techniques for estimation of absolute abundance of wildlife populations have received a lot of attention in recent years. The statistical research has been focused on intensive small-scale studies. Recently, however, wildlife biologists have desired to study populations of animals at very large scales for monitoring purposes. Population indices are widely used in these extensive monitoring programs because they are inexpensive compared to estimates of absolute abundance. A crucial underlying assumption is that the population index (C) is directly proportional to the population density (D). The proportionality constant, ,, is simply the probability of ,detection' for animals in the survey. As spatial and temporal comparisons of indices are crucial, it is necessary to also assume that the probability of detection is constant over space and time. Biologists intuitively recognize this when they design rigid protocols for the studies where the indices are collected. Unfortunately, however, in many field studies the assumption is clearly invalid. We believe that the estimation of detection probability should be built into the monitoring design through a double sampling approach. A large sample of points provides an abundance index, and a smaller sub-sample of the same points is used to estimate detection probability. There is an important need for statistical research on the design and analysis of these complex studies. Some basic concepts based on actual avian, amphibian, and fish monitoring studies are presented in this article. Copyright © 2002 John Wiley & Sons, Ltd. [source] Developing Measurement Theory for Classroom Assessment Purposes and UsesEDUCATIONAL MEASUREMENT: ISSUES AND PRACTICE, Issue 4 2003Susan M. Brookhart In many fields of inquiry, the need for new theoretical developments is often best seen in areas of strain, and strain is apparent in several areas in which the conventions of measurement theory do not quite "fit" classroom assessment. Three areas of strain are analyzed in order to suggest how theoretical development might focus directly on information quality in the classroom assessment context. This article describes the context dependence of classroom assessment, its inextricable relationship with instruction, and its simultaneous formative and summative functions. Thus a case is made for new theoretical developments in the area of measurement in the classroom. [source] Barrel Plating Rhodium Electrode: Application to Flow Injection Analysis of HydrazineELECTROANALYSIS, Issue 14 2005Jun-Wei Sue Abstract We introduce here the application of barrel plating technology for mass production of disposable-type electrodes. Easy for mass production, barrel plating rhodium electrode (Rh-BPE) is for the first time demonstrated for analytical application. Hydrazine was chosen as a model analyte to elucidate the electrocatalytic and analytical ability of the Rh-BPE system in pH,7 phosphate buffer solution. Flow injection analysis (FIA) of hydrazine showed a linear calibration range of 25,1000,ppb with a slope and a regression coefficient of 5,nA/ppb and 0.9946, respectively. Twenty-two replicate injections of 25,ppb hydrazine showed a relative standard deviation of 3.17% indicating a detection limit (S/N=3) of 2.5,ppb. The system can be continuously operated for 1 day without any alteration in the FIA signals and is tolerable to the interference of oxalic acid, gelatine, Triton X-100, and albumin for even up to 100 times excess in concentration with respect to 400,ppb hydrazine. Since the fabrication cost of the electrode is cheap, it is thus disposable in nature. Furthermore, barrel plating technique can be extendable to other transition metals for application in many fields of research interest. [source] Bulk Nanostructured Materials: Non-Mechanical Synthesis,ADVANCED ENGINEERING MATERIALS, Issue 8 2010Yulia Ivanisenko An overview of the synthesis and processing techniques for bulk nanostructured materials that are based on "bottom-up" approaches is presented. Typically, these processes use nanoparticles, which can be produced by a variety of methods in the gas, liquid or solid state, as the basic building blocks. Their assembly into bulk nanostructured materials requires at least one more processing step, such as compaction or the formation of thick films. For certain nanostructures, film deposition techniques can also be employed. A wide range of nanostructures , from thick films with theoretical density to bulk nanocrystalline materials with nanoporosity , exhibiting novel structural and functional properties useful in many fields of applications are presented. Additionally, the properties of these bulk nanostructured materials can be categorized as either tailored, i.e., microstructure-dependent and inherently irreversible, or tunable, i.e., reversible by the application of an external field. Examples of both categories of properties are presented and the special role of the synthesis and processing routes to achieve the necessary nanostructures is emphasized. [source] A designed curved DNA segment that is a remarkable activator of eukaryotic transcriptionFEBS JOURNAL, Issue 24 2006Noriyuki Sumida To identify artificial DNA segments that can stably express transgenes in the genome of host cells, we built a series of curved DNA segments that mimic a left-handed superhelical structure. Curved DNA segments of 288 bp (T32) and 180 bp (T20) were able to activate transcription from the herpes simplex virus thymidine kinase (tk) promoter by approximately 150-fold and 70-fold, respectively, compared to a control in a transient transfection assay in COS-7 cells. The T20 segment was also able to activate transcription from the human adenovirus type 2 E1A promoter with an 18-fold increase in the same assay system, and also activated transcription from the tk promoter on episomes in COS-7 cells. We also established five HeLa cell lines with genomes containing T20 upstream of the transgene promoter and control cell lines with T20 deleted from the transgene locus. Interestingly, T20 was found to activate transcription in all the stable transformants, irrespective of the locus. This suggests that the T20 segment may allow stable expression of transgenes, which is of importance in many fields, and may also be useful for the construction of nonviral vectors for gene therapy. [source] Evolution on ecological time-scalesFUNCTIONAL ECOLOGY, Issue 3 2007S. P. CARROLL Summary 1Ecologically significant evolutionary change, occurring over tens of generations or fewer, is now widely documented in nature. These findings counter the long-standing assumption that ecological and evolutionary processes occur on different time-scales, and thus that the study of ecological processes can safely assume evolutionary stasis. Recognition that substantial evolution occurs on ecological time-scales dissolves this dichotomy and provides new opportunities for integrative approaches to pressing questions in many fields of biology. 2The goals of this special feature are twofold: to consider the factors that influence evolution on ecological time-scales , phenotypic plasticity, maternal effects, sexual selection, and gene flow , and to assess the consequences of such evolution , for population persistence, speciation, community dynamics, and ecosystem function. 3The role of evolution in ecological processes is expected to be largest for traits that change most quickly and for traits that most strongly influence ecological interactions. Understanding this fine-scale interplay of ecological and evolutionary factors will require a new class of eco-evolutionary dynamic modelling. 4Contemporary evolution occurs in a wide diversity of ecological contexts, but appears to be especially common in response to anthropogenic changes in selection and population structure. Evolutionary biology may thus offer substantial insight to many conservation issues arising from global change. 5Recent studies suggest that fluctuating selection and associated periods of contemporary evolution are the norm rather than exception throughout the history of life on earth. The consequences of contemporary evolution for population dynamics and ecological interactions are likely ubiquitous in time and space. [source] Nanopatterning Soluble Multifunctional Materials by Unconventional Wet LithographyADVANCED MATERIALS, Issue 10-11 2009Massimiliano Cavallini Abstract Molecular multifunctional materials have potential applications in many fields of technology, such as electronics, optics and optoelectronics, information storage, sensing, and energy conversion and storage. These materials are designed exhibit enhanced properties, and at the same time are endowed with functional groups that control their interactions, and hence self-organization, into a variety of supramolecular architectures. Since most of the multifunctional materials are soluble, lithographic methods suitable for solutions are attracting increasing interest for the manufacturing of the new materials and their applications. The aim of this paper is to highlight some of the recent advances of solution-based fabrication of multifunctional materials. We explain and examine the principles, processes, materials, and limitations of this class of patterning techniques, which we term unconventional wet lithographies (UWLs). We describe their ability to yield patterns and structures whose feature sizes range from nanometers to micrometers. In the following sections, we focus our attention on micromolding in capillaries, lithographically controlled wetting, and grid-assisted deposition, the most used methods demonstrated to lead to fully operating devices. [source] Synthesis of Carbon-Nanotube Composites Using Supercritical Fluids and Their Potential ApplicationsADVANCED MATERIALS, Issue 7 2009Zhimin Liu Abstract Carbon-nanotube (CNT) composites have attracted a lot of attention because of their potential applications in many fields. Here, recent advances in the synthesis of CNT composites using supercritical fluids (SCFs) are highlighted. SCFs exhibit unique features for the synthesis of composites because of their unusual properties, such as low viscosity, high diffusivity, near-zero surface tension, and tunability. Preliminary studies show that SCFs show unusual advantages for the synthesis of CNT composites. The morphologies and structures of the resultant CNT composites can be tuned by changing the solvent properties. The SCF methods not only provide a green route for the synthesis of composites, but also result in nanostructures that have not yet been produced by conventional methods. Moreover, the potential applications of the resultant CNT composites are also discussed. [source] Computation of the J -integral for large strainsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 12 2008Ágnes Horváth Abstract The phenomenon of failure by catastrophic crack propagation in structural materials poses problems of design and analysis in many fields of engineering. Cracks are present to some degree in all structures. They may exist as basic defects in the constituent materials or they may be induced in construction or during service life. Using the finite element method, a lot of papers deal with the calculation of stress intensity factors for two- and three-dimensional geometries containing cracks of different shapes under various loadings to elastic bodies. In order to increase the accuracy of the results, special elements have been used. They are described together with methods for calculating the stress intensity factors from the computed results. At the vicinity of a crack tip, the strains are not always small, but they may also be large. In this case, the J -integral can also be applied to characterize the cracks in elastic or elastic,plastic bodies. This paper describes the computation of the two-dimensional J -integral for large strains to elastic and elastic,plastic bodies and represents some numerical examples. Copyright © 2007 John Wiley & Sons, Ltd. [source] Application of computerized image analysis in pigmentary skin diseasesINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 1 2001Eun-So Lee MD Background Melanocyte number and the amount of melanin pigment are related to diagnosis and treatment of pigmentary skin diseases. Various histologic methods are used, such as Fontana-Masson stain for melanin pigment or immunohistochemical stain for melanocytes. Recently, computerized image analysis has been applied to many fields to avoid interobserver bias. In this study, we applied a computerized image analysis to assess the melanin content and melanocyte density of human epidermis. Methods We evaluated the skin biopsy specimens (paraffin blocks) from normal human skin (33 ± 6.6, n = 11) and diseased skins; vitiligo (32 ± 10.0, n = 8), melasma (35 ± 8.6, n = 11), and lentigo senilis (40 ± 7.2, n = 11) (mean age ± SD). Each specimen was stained with Fontana,Masson for melanin pigments and immunohistochemical method for melanocytes. Quantitative analysis of melanin pigment and melanocyte number (density) were investigated through two methods: (1) two dermatologists measured the visual scales; and (2) computerized image analysis was used to measure melanin content indices (MCI). The data were evaluated using one-way anova. Results The visual scale of the Fontana,Masson stain was the highest for lentigo senilis (3.8 ± 0.40), followed by melasma (2.6 ± 0.67), normal skin (1.8 ± 0.60) and vitiligo (0) (P < 0.05). These findings were consistent with objective measurements made by computerized image analysis. MCI values were 120.3 ± 20.74 for lentigo senilis, 81.1 ± 19.27 for melasma, 45.5 ± 16.92 for normal skin, and 0.3 ± 0.30 for vitiligo in decreasing order (P < 0.05). MC/1E (melanocyte number per 1 mm epidermis) was about two fold larger in lentigo senilis (18.1 ± 8.92) than melasma (9.7 ± 2.40) or normal skin (9.3 ± 2.67) (P < 0.05). MC/1B (melanocyte number per 1 mm basal layer) was about 1.5 fold higher in lentigo senilis (13.5 ± 4.17), compared to normal skin (9.0 ± 3.55) (P < 0.05). Melasma showed increased melanocyte numbers compared to normal skin, but it was not statistically significant (P > 0.05). Conclusion We believe this computerized image analysis could be useful tool for diagnosis and comparison of interval changes in pigmentary diseases like melasma or lentigo senilis by quantifying melanin pigments or melanocytes in skin biopsy specimens. [source] Properties and performance of orthogonal neural network in function approximationINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 12 2001Chieh F. Sher Backpropagation neural network has been applied successfully to solving uncertain problems in many fields. However, unsolved drawbacks still exist such as the problems of local minimum, slow convergence speed, and the determination of initial weights and the number of processing elements. In this paper, we introduce a single-layer orthogonal neural network (ONN) that is developed based on orthogonal functions. Since the processing elements are orthogonal to one another and there is no local minimum of the error function, the orthogonal neural network is able to avoid the above problems. Among the five existing orthogonal functions, Legendre polynomials and Chebyshev polynomials of the first kind have the properties of recursion and completeness. They are the most suitable to generate the neural network. Some typical examples are given to show their performance in function approximation. The results show that ONN has excellent convergence performance. Moreover, ONN is capable of approximating the mathematic model of backpropagation neural network. Therefore, it should be able to be applied to various applications that backpropagation neural network is suitable to solve. © 2001 John Wiley & Sons, Inc. [source] Time asymmetry, nonexponential decay, and complex eigenvalues in the theory and computation of resonance statesINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 2 2002Cleanthes A. Nicolaides Abstract Stationary-state quantum mechanics presents no difficulties in defining and computing discrete excited states because they obey the rules established in the properties of Hilbert space. However, when this idealization has to be abandoned to formulate a theory of excited states dissipating into a continuous spectrum, the problem acquires additional interest in many fields of physics. In this article, the theory of resonances in the continuous spectrum is formulated as a problem of decaying states, whose treatment can entail time-dependent as well as energy-dependent theories. The author focuses on certain formal and computational issues and discusses their application to polyelectronic atomic states. It is argued that crucial to the theory is the understanding and computation of a multiparticle localized wavepacket, ,0, at t = 0, having a real energy E0. Assuming this as the origin, without memory of the excitation process, the author discusses aspects of time-dependent dynamics, for t , 0 as well as for t , ,, and the possible significance of nonexponential decay in the understanding of timeasymmetry. Also discussed is the origin of the complex eigenvalue Schrödinger equation (CESE) satisfied by resonance states and the state-specific methodology for its solution. The complex eigenvalue drives the decay exponentially, with a rate ,, to a good approximation. It is connected to E0 via analytic continuation of the complex self-energy function, A(z), (z is complex), into the second Riemann sheet, or, via the imposition of outgoing wave boundary conditions on the stationary state Schrödinger equation satisfied by the Fano standing wave superposition in the vicinity of E0. If the nondecay amplitude, G(t), is evaluated by inserting the unit operator I = ,dE|E> Online temperature measurement and simultaneous diameter estimation of fibers by thermography of the spinline in the melt spinning processADVANCES IN POLYMER TECHNOLOGY, Issue 3 2004M. Golzar Abstract Online measurements of the temperature and the diameter of fibers in the melt spinning process of thermoplastics are discussed. The temperature and the diameter of fibers can be applied in many fields such as fiber formation modelling, cooling rate behavior (Nusselt number), and rheological investigations (apparent extensional viscosity) of polymers. The online measurements along the spinline were carried out with an infrared camera during the melt spinning process. Two different experiments were designed and carried out to find the correction factor, i.e., the emissivity. The results show that the emissivity correction factor depends on the polymer type and the fiber diameter. Usually the diameter of the fibers is measured by an instrument or by direct velocity measurements invoking the continuity equation. In this new approach the diameter is found directly by the evaluation of the measured temperature. Therefore only one apparatus, namely an infrared camera taking snapshots, is required to find the fiber diameter. The key of this method can be seen in the temperature difference between the fiber and the environment. A mathematical procedure was developed to estimate the diameter of the fiber from the distribution curve. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 176,185, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20008 [source] Internal amplification controls have not been employed in fungal PCR hence potential false negative resultsJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2007R.R.M. Paterson Abstract Polymerase chain reaction (PCR) is subject to false negative results. Samples of fungi with the genes of interest (e.g. a disease or mycotoxin) may be categorized as negative and safe as a consequence. Fungi are eukaryotic organisms that are involved in many fields of human activity such as antibiotic, toxin and food production. Certain taxa are implicated in human, animal and plant diseases. However, fungi are difficult to identify and PCR techniques have been proposed increasingly for this purpose. Internal amplification controls (IACs) will ameliorate the situation and need to become mandatory. These are nucleic acids that posses a sequence which will provide a PCR product (i) using the same primers employed for the target gene, and (ii) that will not coincide on the gel with the product of the target gene. Only one group of workers employed an IAC, to respond to potential inhibition, which was reported in 1995 from this present assessment of numerous reports. Inhibitors in cultures need to be minimized, and secondary metabolites are an obvious source. The fields reviewed herein include medical mycology, mycotoxicology, environmental mycology and plant mycology. The conclusion is that previous reports are compromised because IACs have not been employed in fungal PCR; future research must include this control at an early stage. [source] Electrosprayed polymer particles: Effect of the solvent propertiesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2009Chul Ho Park Abstract Electrospraying technology has been studied in many fields to produce particles of various substances from nanoscale to microscale sizes. Unlike pure liquids, droplets formed by electrospraying that are comprised of polymer solutions undergo additional solidification processes involving solvent evaporation, which primarily determine the particle size and morphology. Herein, the effects of the solvent properties on the morphology and dimensions of solidified particles were systematically studied. In general, the size of the solidified spherical particles with smooth surfaces reflected that of the initially formed liquid droplets, which could partially be estimated by theoretical equations developed for pure liquids. Particle sizes increased with an increase in polymer content and a decrease in the boiling point of the volatile solvent. Inhomogeneous drying processes related to phase separation or skin formation resulted in hollow, cuplike, and porous particle structures, with particle sizes and morphologies that were outside of the scope of the theoretical treatments. The selection of a proper solvent or solvent mixture seemed to be a convenient way to control the particle morphologies, such as hollow, cuplike, or porous structures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] In vivo acute toxicity of titanium dioxide nanoparticles to mice after intraperitioneal injectionJOURNAL OF APPLIED TOXICOLOGY, Issue 4 2009Jinyuan Chen Abstract Because of its excellent optical performance and electrical properties, TiO2 has a wide range of applications in many fields. It is often considered to be physiologically inert to humans. However, some recent studies have reported that nano-sized TiO2 may generate potential harm to the environment and humans. In this paper the in vivo acute toxicity of nano-sized TiO2 particles to adult mice was investigated. Mice were injected with different dosages of nano-sized TiO2 (0, 324, 648, 972, 1296, 1944 or 2592 mg kg,1). The effects of particles on serum biochemical levels were evaluated at various time points (24 h, 48 h, 7 days and 14 days). Tissues (spleen, heart, lung, kidney and liver) were collected for titanium content analysis and histopathological examination. Treated mice showed signs of acute toxicity such as passive behavior, loss of appetite, tremor and lethargy. Slightly elevated levels of the enzymes alanine aminotransferase and aspartate aminotransferase were found from the biochemical tests of serum whereas blood urea nitrogen was not significantly affected (P <0.05). The accumulation of TiO2 was highest in spleen (P <0.05). TiO2 was also deposited in liver, kidney and lung. Histopathological examinations showed that some TiO2 particles had entered the spleen and caused the lesion of spleen. Thrombosis was found in the pulmonary vascular system, which could be induced by the blocking of blood vessels with TiO2 particles. Moreover, hepatocellular necrosis and apoptosis, hepatic fibrosis, renal glomerulus swelling and interstitial pneumonia associated with alveolar septal thickening were also observed in high-dose groups. Copyright © 2009 John Wiley & Sons, Ltd. [source] Digitization and geo-referencing of botanical distribution mapsJOURNAL OF BIOGEOGRAPHY, Issue 7 2002Christian A. Schölzel Aim In many fields of research, valuable information is stored in atlases and maps which are only available as printed media. Scientists who are interested in computational analysis often seek to digitize the data to make it accessible for numerical calculations. In this paper, an approach using the example of digitizing distribution maps taken from plant-taxonomic atlases is described. For this purpose, a software tool has been built for application in the Sonderforschungsbereich 350 `Interactions between and Modelling of Continental Geosystems' at the University of Bonn. Its functionality has to be simple in use and capable of transforming fields drawn on geographical maps into grid data even where the type of map projection is unknown. Location As an example, plant distributions over Europe and Asia have been digitized. Methods To achieve this aim through an objective statistical analysis, the local deterministic approximation has been used for geo-referencing. Results For this reason the development of a new software tool was required. Although there is a large market for related software from Geographical Information Systems (GIS), none of the available GIS-programs appeared to be capable of geo-referencing maps with unidentified projections. Rather than to give a product comparison, this paper aims on the methodology and mathematical formalism. Main conclusions The developed algorithm is a handy tool to capture data from maps based on obscure projections. Valuable historical maps, which are problematic for standard GIS-programs, can be made accessible for modern research work. [source] The membrane emulsification process,a reviewJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2004C Charcosset Abstract Membrane emulsification has received increasing attention over the last 10 years, with potential applications in many fields. In the membrane emulsification process, a liquid phase is pressed through the membrane pores to form droplets at the permeate side of a membrane; the droplets are then carried away by a continuous phase flowing across the membrane surface. Under specific conditions, monodispersed emulsions can be produced using this technique. The purpose of the present paper is to provide a review on the membrane emulsification process including: principles of membrane emulsification, influence of process parameters and industrial applications. Small-scale applications such as drug delivery systems, food emulsions, and the production of monodispersed microspheres are also included. Compared with conventional techniques for emulsification, membrane processes offer advantages such as control of average droplet diameter by average membrane pore size and lower energy input. Copyright © 2004 Society of Chemical Industry [source] Future integrated learning environments with multimediaJOURNAL OF COMPUTER ASSISTED LEARNING, Issue 1 2001T. Okamoto Abstract, Recent progress in information technology hardware and the spread of the Internet have opened a variety of new ways for many fields. Although slower than the business field to catch up with these new developments, the educational field has gradually migrated towards the World-wide web, mostly under the slogan of free, accessible education, to and from anyplace, at anytime. This development triggered an important shift from the teaching paradigm to the learning paradigm. However, slow network speed hindered the first learning environments from being more than simple, electronic text-books. The latest trends making use of increased bandwidths and integrating various media to enhance learning. Moreover, for obtaining learner-oriented, customised learning environ-ments, intelligent tutoring techniques are being adapted and developed for the web. This paper presents these trends on one hand, but on the other hand, also addresses the dangers and pitfalls that such an avalanche of change can bring and stresses the task of ensuring that the real goal of enhancing and improving learning is not overlooked. [source] Positive Interactions: Crucial Organizers in a Plant CommunityJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 2 2006Dong-Liang Cheng Abstract For more than a century, ecologists have concentrated on competition as a crucial process for community organization. However, more recent experimental investigations have uncovered the striking influence of positive interactions on the organization of plant communities. Complex combinations of competition and positive interactions operating simultaneously among plant species seem to be widespread in nature. In the present paper, we reviewed the mechanism and ecological importance of positive interactions in plant communities, emphasizing the certainties and uncertainties that have made it an attractive area of research. Positive interactions, or facilitation, occur when one species enhances the survival, growth, or richness of another. The importance of facilitation in plant organization increases with abiotic stress and the relative importance of competition decreases. Only by combining plant interactions and the many fields of biology can we fully understand how and when the positive interactions occur. (Managing editor: Ya-Qin Han) [source] Visual gene diagnosis of HBV and HCV based on nanoparticle probe amplification and silver staining enhancementJOURNAL OF MEDICAL VIROLOGY, Issue 2 2003Ye-Fu Wang Abstract A visual gene-detecting technique using nanoparticle-supported gene probes is described. With the aid of gold nanoparticle-supported 3,-end,mercapto-derivatized oligonucleotide serving as detection probe, and 5,-end ,amino-derivatized oligonucleotide immobilized on glass surface acting as capturing probe, target DNA was detected visually by sandwich hybridization based on highly sensitive "nano-amplification" and silver staining. Different genotypes of Hepatitis B and C viruses in the serum samples from infected patients were detected using home-made HBV, HCV, and HBV/HCV gene chips by the gold/silver nanoparticle staining amplification method. The present visual gene-detecting technique may avoid limitations with the reported methods, for its high sensitivity, good specificity, simplicity, speed, and cheapness. This technique has potential applications in many fields, especially in multi-gene detection gene chips coupled with the detection will find applications in clinic. Additionally, resonance Rayleigh light scattering (RLS) spectroscopy is used, for the first time, to judge and monitor the immobilization of gene probes on gold nanoparticle surfaces. J. Med. Virol. 70: 205,211, 2003. © 2003 Wiley-Liss, Inc. [source] ON SOCIAL NETWORK ANALYSIS IN A SUPPLY CHAIN CONTEXT,JOURNAL OF SUPPLY CHAIN MANAGEMENT, Issue 2 2009STEPHEN P. BORGATTI The network perspective is rapidly becoming a lingua franca across virtually all of the sciences from anthropology to physics. In this paper, we provide supply chain researchers with an overview of social network analysis, covering both specific concepts (such as structural holes or betweenness centrality) and the generic explanatory mechanisms that network theorists often invoke to relate network variables to outcomes of interest. One reason for discussing mechanisms is to facilitate appropriate translation and context-specific modification of concepts rather than blind copying. We have also taken care to apply network concepts to both "hard" types of ties (e.g., materials and money flows) and "soft" types of ties (e.g., friendships and sharing-of-information), as both are crucial (and mutually embedded) in the supply chain context. Another aim of the review is to point to areas in other fields that we think are particularly suitable for supply chain management (SCM) to draw network concepts from, such as sociology, ecology, input,output research and even the study of romantic networks. We believe the portability of many network concepts provides a potential for unifying many fields, and a consequence of this for SCM may be to decrease the distance between SCM and other branches of management science. [source] The ,heuristics and biases' bias in expert elicitationJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES A (STATISTICS IN SOCIETY), Issue 1 2008Mary Kynn Summary., In the early 1970s Tversky and Kahneman published a series of papers on ,heuristics and biases' describing human inadequacies in assessing probabilities, culminating in a highly popular article in Science. This seminal research has been heavily cited in many fields, including statistics, as the definitive research on probability assessment. Curiously, although this work was debated at the time and more recent work has largely refuted many of the claims, this apparent heuristics and biases bias in elicitation research has gone unremarked. Over a decade of research into the frequency effect, the importance of framing, and cognitive models more generally, has been almost completely ignored by the statistical literature on expert elicitation. To remedy this situation, this review offers a guide to the psychological research on assessing probabilities, both old and new, and gives concrete guidelines for eliciting expert knowledge. [source] A latent Gaussian model for compositional data with zerosJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES C (APPLIED STATISTICS), Issue 5 2008Adam Butler Summary., Compositional data record the relative proportions of different components within a mixture and arise frequently in many fields. Standard statistical techniques for the analysis of such data assume the absence of proportions which are genuinely zero. However, real data can contain a substantial number of zero values. We present a latent Gaussian model for the analysis of compositional data which contain zero values, which is based on assuming that the data arise from a (deterministic) Euclidean projection of a multivariate Gaussian random variable onto the unit simplex. We propose an iterative algorithm to simulate values from this model and apply the model to data on the proportions of fat, protein and carbohydrate in different groups of food products. Finally, evaluation of the likelihood involves the calculation of difficult integrals if the number of components is more than 3, so we present a hybrid Gibbs rejection sampling scheme that can be used to draw inferences about the parameters of the model when the number of components is arbitrarily large. [source] Fabrication and properties of nano-ZnO/glass-fiber-reinforced polypropylene compositesJOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 3 2010Yi-Hua Cui Polypropylene (PP) is widely used in many fields, such as automobiles, medical devices, office equipment, pipe, and architecture. However, its high brittle transformation temperature, low mechanical strength, dyeing properties, antistatic properties, and poor impact resistance, considerably limit its further applications. Nano-ZnO treated by KH550 coupling agent and glass fibers (GFs) were introduced in order to improve the mechanical performance and flowability of PP in this research. The crystallization behavior and microstructure of nano-ZnO/GFs/PP hybrid composites were analyzed by differential scanning calorimetry, transmission electron microscopy, and scanning electron microscopy. The effect of crystallization behavior on the mechanical properties of the nanocomposites was investigated and analyzed. The results indicated that nano-ZnO surface-coupled by KH550 could be uniformly dispersed in the PP matrix. The incorporation of nano-ZnO and GFs resulted in increases of the crystallization temperature and crystallization rate of PP and a decrease of the crystallization degree. The introduction of nano-ZnO and GFs also enhanced the tensile strength and impact toughness of the hybrid composites and improved their fluidity. Composites containing 2% of nano-ZnO and 40% of GFs possessed the optimum mechanical properties. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers [source] Gesture Gives a Hand to Language and Learning: Perspectives from Cognitive Neuroscience, Developmental Psychology and EducationLINGUISTICS & LANGUAGE COMPASS (ELECTRONIC), Issue 4 2008Spencer D. Kelly People of all ages, cultures and backgrounds gesture when they speak. These hand movements are so natural and pervasive that researchers across many fields , from linguistics to psychology to neuroscience , have claimed that the two modalities form an integrated system of meaning during language production and comprehension. This special relationship has implications for a variety of research and applied domains. Gestures may provide unique insights into language and cognitive development, and also help clinicians identify, understand and even treat developmental disorders in childhood. In addition, research in education suggests that teachers can use gesture to become even more effective in several fundamental aspects of their profession, including communication, assessment of student knowledge, and the ability to instill a profound understanding of abstract concepts in traditionally difficult domains such as language and mathematics. This work converging from multiple perspectives will push researchers and practitioners alike to view hand gestures in a new and constructive way. [source] Indication of Local Phase Separation in Polyimide/Silica Hybrid Polymers,MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 16 2010Antonino Bartolotta Abstract PI/SiO2 hybrid polymers involving the in situ generation of SiO2 particles through the sol/gel route have emerged as promising materials in many fields of modern technology thanks to their unique structural characteristics. In this paper their structural and dynamic properties were investigated by FT-IR and DMTA as a function of SiO2 content. All data consistently highlight a loosening of polymeric structure due to the presence of SiO2 nanoparticles and suggest a silica-induced structural change most probably due to a sub-micrometer scale SiO2 phase separation. Our results demonstrate how the analysis of sub-glass ,-relaxation dynamics can be exploited to investigate sub-micro phase segregation in such materials. [source] Theoretical investigation on multinuclear NMR chemical shifts of some tris(trifluoromethyl)boron complexesMAGNETIC RESONANCE IN CHEMISTRY, Issue 8 2009Jun Zhang Abstract Tris(trifluoromethyl)boron complexes have unusual properties and may find applications in many fields of chemistry, biology, and physics. To gain insight into their NMR properties, the isotropic 11B, 13C, and 19F NMR chemical shifts of a series of tris(trifluoromethyl)boron complexes were systematically studied using the gauge-included atomic orbitals (GIAO) method at the levels of B3LYP/6-31 + G(d,p)//B3LYP/6-31G* and B3LYP/6-311 + G(d,p)//B3LYP/6-311 + G(d,p). Solvent effects were taken into account by polarizable continuum models (PCM). The calculated results were compared with the experimental values. The reason that the structurally inequivalent fluorine atoms in a specific species give a same chemical shift in experimental measurements is attributed to the fast rotation of CF3 group around the BC(F3) bond because of the low energy barrier. The calculated 11B, 13C(F3), and 19F chemical shifts are in good agreement with the experimental measurements, while the deviations of calculated 13C(X, X = O, N) chemical shifts are slightly large. For the latter, the average absolute deviations of the results from B3LYP/6-311 + G(d,p)//B3LYP/6-311 + G(d,p) are smaller than those from B3LYP/6-31 + G(d,p)//B3LYP/6-31G*, and the inclusion of PCM reduces the deviation values. The calculated 19F and 11B chemical shieldings of (CF3)3BCO are greatly dependent on the optimized structures, while the influence of structural parameters on the calculated 13C chemical shieldings is minor. Copyright © 2009 John Wiley & Sons, Ltd. [source] The thioredoxin system,From science to clinicMEDICINAL RESEARCH REVIEWS, Issue 1 2004Stephan Gromer Abstract The thioredoxin system,formed by thioredoxin reductase and its characteristic substrate thioredoxin,is an important constituent of the intracellular redox milieu. Interactions with many different metabolic pathways such as DNA-synthesis, selenium metabolism, and the antioxidative network as well as significant species differences render this system an attractive target for chemotherapeutic approaches in many fields of medicine,ranging from infectious diseases to cancer therapy. In this review we will present and evaluate the preclinical and clinical results available today. Current trends in drug development are emphasized. © 2003 Wiley Periodicals, Inc. Med Res Rev, 24, No. 1, 40,89, 2004 [source]
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