Home About us Contact
|
Home About us Contact | ||
|
|
||
Single Line (single + line)
Selected AbstractsHow is Education Possible?EDUCATIONAL PHILOSOPHY AND THEORY, Issue 1 2001Preliminary investigations for a theory of education The following text is the result of our ongoing discussions about the notion of intersubjectivity and its significance for an understanding of the process of education. Rather than merging our sometimes diverging ideas into one single line of argument, we decided to try if we could make the movement of divergence and convergence of our thoughts visible in the text itself. Although we definitely explore different pathways, these pathways lead to a similar insight. This is, that it is not the educator who educates, but that it is the educational ,situation',a situation constituted though not determined by the interaction between the educator and the student,which educates. This educational situation, which one of us describes as an ,in between space', emerges from the interaction between the educator and the student. In this respect we can say that it results from the difference between the partners in education. The in-between space of education is an emerging reality, which not only comes into existence as a result of the difference between the partners in education but in fact only exists in this difference. It is precisely in this respect that the form of the following article provides an example of what we want to say about the process of education. The point is, to put it briefly, that this article contains or expresses a meaning that results from the difference between the two texts, but this meaning is neither something that can be attributed to the two texts as such (in this sense this emerging meaning is constituted though not determined by the two texts), nor,and this is crucial,is it something that can be articulated in any positive way in a third text. The interaction between our two texts therefore creates a reality that results from the difference between the texts and only exists in this difference. The order of authorship expresses the fact that the first author wrote the left column and the second author the right column. [source] Analysis and characterization of package resonanceINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 1 2005El-Badawy El-Sharawy Abstract This article presents FDTD analysis and prediction of the overall effects of the resonance in ceramic and plastic packages. Practical structures that result in strong resonance effects are investigated, such as coupled cross lines with a via transition and multiple via transitions on a single line. A detailed study of the mutual coupling, including resonance effects, is also performed and presented. The results of the analysis indicate that the package performance can be very sensitive to the resonance effects. A broadband equivalent-circuit model for multiple transition discontinuities (two via holes) on a single line has been developed and presented. Good agreement between the frequency response of the FDTD and the circuit models has been achieved over a broad band of frequencies. The analysis presented in this article provides insight about the limits at which coupling effects on the overall package performance can be neglected. The equivalent-circuit model presented in this article can greatly simplify the analysis and simulation of a complex package, including several transition discontinuities, assuming that the coupling is small. © 2004 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005. [source] Correlation of relative rates of chromyl chloride oxidation and chromic acid oxidation of acyclic alkenes versus alkene IPs and HOMOsJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 11 2004Donna J. Nelson Abstract Plots of logarithms of relative reaction rates of chromyl chloride oxidation and of chromic acid oxidation of alkenes (log,krel values) versus alkene ionization potentials (IPs) and versus their highest occupied molecular orbital energy levels (HOMOs) demonstrate excellent correlations. Each plot has a similar appearance and shows a single line with a positive slope. The results indicate that the rate-determining step of each title reaction involves an electrophilic attack on the alkene ,-bond without significant steric effects; this supports a proposed 2,+,3 cycloaddition mechanism and disfavors a proposed stepwise 2,+,2 cycloaddition mechanism. Comparison is made with other d0 transition metal complexes that oxidize alkenes. Copyright © 2004 John Wiley & Sons, Ltd. [source] A new approach to automated first-order multiplet analysisMAGNETIC RESONANCE IN CHEMISTRY, Issue 5 2002Sergey Golotvin Abstract The dependence of the values of NMR spin,spin coupling constants on molecular conformation can be a valuable tool in the structure determination process. The continuing increase in the resonance frequency of modern NMR spectrometers allows an increasing number of resonances to be examined using first-order multiplet analysis. While this can easily be done for the simplest patterns (doublets, triplets, quartets), more complex patterns can be extremely difficult to analyze. The task of deducing the coupling constant values from a multiplet is the reverse process of generating a conventional splitting tree from a single line (chemical shift) by sequential branching using a given set of coupling constants. We present a simple, straightforward method of deducing coupling constant values from first-order multiplets based on a general inverted splitting tree algorithm but also including a peak intensity normalization procedure that utilizes multiplet symmetry and generates a set of possible first-order intensity distribution patterns. When combined with an inverted splitting tree algorithm, it is possible to find an intensity pattern that allows the deduction of a proper set of coupling constants. Copyright © 2002 John Wiley & Sons, Ltd. [source] 55Mn NMR study in magnetically ordered state of perovskite manganitesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2004K. Shimizu Abstract We present NMR results of Pr1,xSrxMnO3 and their lacunar samples, and also present results of the single crystalline layered manganites La1.2Sr1.8Mn2O7 and La1.2Sr1.6Ca0.2Mn2O7. In Pr1,xSrxMnO3, a single resonance line is observed for 0.27 , x , 0.4, which indicates the sample to be in a metallic state. In the Pr and Sr deficient samples, the NMR line arising from Mn2+ is observed. Introducing deficiency to Pr or Sr sites, a charge disproportionation of the type 2Mn3+, Mn2+ + Mn4+ probably occurs. For La1.2Sr1.8Mn2O7 and La1.2Sr1.6Ca0.2Mn2O7 compounds, the NMR spectra under an external field of 1.5 T are broad and spread with several distinct lines in the frequency range 310,420 MHz. This is different from the results of La1,xSrxMnO3 and Pr1,xSrxMnO3 with a metallic state, where a single line has been observed. The distinct NMR lines are ascribed to Mn4+, Mn3+ and metallic phase, taking account of the results for La1,xSrxMnO3 and Pr1,xSrxMnO3. In addition to the NMR line from the metallic phase, the observation of Mn3+ and Mn4+ lines suggests a phase separation at low temperature in La1.2Sr1.8Mn2O7 and La1.2Sr1.6Ca0.2Mn2O7. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Use and misuse of the reduced major axis for line-fittingAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 3 2009Richard J. Smith Abstract Many investigators use the reduced major axis (RMA) instead of ordinary least squares (OLS) to define a line of best fit for a bivariate relationship when the variable represented on the X -axis is measured with error. OLS frequently is described as requiring the assumption that X is measured without error while RMA incorporates an assumption that there is error in X. Although an RMA fit actually involves a very specific pattern of error variance, investigators have prioritized the presence versus the absence of error rather than the pattern of error in selecting between the two methods. Another difference between RMA and OLS is that RMA is symmetric, meaning that a single line defines the bivariate relationship, regardless of which variable is X and which is Y, while OLS is asymmetric, so that the slope and resulting interpretation of the data are changed when the variables assigned to X and Y are reversed. The concept of error is reviewed and expanded from previous discussions, and it is argued that the symmetry-asymmetry issue should be the criterion by which investigators choose between RMA and OLS. This is a biological question about the relationship between variables. It is determined by the investigator, not dictated by the pattern of error in the data. If X is measured with error but OLS should be used because the biological question is asymmetric, there are several methods available for adjusting the OLS slope to reflect the bias due to error. RMA is being used in many analyses for which OLS would be more appropriate. Am J Phys Anthropol, 2009. © 2009 Wiley-Liss, Inc. [source] The evolution of trade-offs: geographic variation in call duration and flight ability in the sand cricket, Gryllus firmusJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 4 2003D. A. Roff Abstract Quantitative genetic theory assumes that trade-offs are best represented by bivariate normal distributions. This theory predicts that selection will shift the trade-off function itself and not just move the mean trait values along a fixed trade-off line, as is generally assumed in optimality models. As a consequence, quantitative genetic theory predicts that the trade-off function will vary among populations in which at least one of the component traits itself varies. This prediction is tested using the trade-off between call duration and flight capability, as indexed by the mass of the dorsolateral flight muscles, in the macropterous morph of the sand cricket. We use four different populations of crickets that vary in the proportion of macropterous males (Lab = 33%, Florida = 29%, Bermuda = 72%, South Carolina = 80%). We find, as predicted, that there is significant variation in the intercept of the trade-off function but not the slope, supporting the hypothesis that trade-off functions are better represented as bivariate normal distributions rather than single lines. We also test the prediction from a quantitative genetical model of the evolution of wing dimorphism that the mean call duration of macropterous males will increase with the percentage of macropterous males in the population. This prediction is also supported. Finally, we estimate the probability of a macropterous male attracting a female, P, as a function of the relative time spent calling (P = time spent calling by macropterous male/(total time spent calling by both micropterous and macropterous male). We find that in the Lab and Florida populations the probability of a female selecting the macropterous male is equal to P, indicating that preference is due simply to relative call duration. But in the Bermuda and South Carolina populations the probability of a female selecting a macropterous male is less than P, indicating a preference for the micropterous male even after differences in call duration are accounted for. [source] | |||||||||||||