Monte Carlo model for electron degradation in methane

We present a Monte Carlo model for degradation of 1-10,000 eV electrons in an atmosphere of methane. The electron impact cross sections for CH4 are compiled and analytical representations of these cross sections are used as input to the model.model.Yield spectra, which provides information about the number of inelastic events that have taken place in each energy bin, is used to calculate the yield (or population) of various inelastic processes. The numerical yield spectra, obtained from the Monte Carlo simulations, is represented analytically, thus generating the Analytical Yield Spectra (AYS). AYS is employed to obtain the mean energy per ion pair and efficiencies of various inelastic processes.Mean energy per ion pair for neutral CH4 is found to be 26 (27.8) eV at 10 (0.1) keV. Efficiency calculation showed that ionization is the dominant process at energies >50 eV, for which more than 50% of the incident electron energy is used. Above 25 eV, dissociation has an efficiency of 27%. Below 10 eV, vibrational excitation dominates. Contribution of emission is around 1.2% at 10 keV. Efficiency of attachment process is 0.1% at 8 eV and efficiency falls down to negligibly small values at energies greater than 15 eV. The efficiencies can be used to calculate volume production rate in planetary atmospheres by folding with electron production rate and integrating over energyComment: 12 figures, 3 table

Lexical Similarities and Differences in the Mathematics, Science and English Language Textbooks

The teaching of Science and Math in English in Malaysia is an area of great concern to educators and students alike. This study looks, in particular, at the common word classes among keywords identified in the Science, Math and English language Form One textbooks used in Malaysia and the differences in language use identified in the Science and Math textbooks

Expected resurgences and symbolic powers of ideals

We give explicit criteria that imply the resurgence of a self-radical ideal in a regular ring is strictly smaller than its codimension, which in turn implies that the stable version of Harbourne's conjecture holds for such ideals. This criterion is used to give several explicit families of such ideals, including the defining ideals of space monomial curves. Other results generalize known theorems concerning when the third symbolic power is in the square of an ideal, and a strong resurgence bound for some classes of space monomial curves.Comment: Final version to appear in the Journal of the London Mathematical Societ

The design and construction of flat rectangular otter boards for bottom trawling: a review

The design and construction of the otter board is a subject of great importance for economy in trawling. This review incorporates a historical resume tracing the change and development• of otter boards. The size of the otter board and its relationship with the horse power of the engine and size of the net and the methods of rigging are dealt with. The factors influencing the horizontal spread are discussed. The effect of the angles of attack, heel and tilt and the ground reaction on the force coefficients have been reviewed and discussed with particular reference to flat rectangular otter boards used for bottom trawling. A short account of other designs of otter boards used for improved efficiency is given. Suggestion for improving the efficacy of otter boards based on the work hitherto done has been made. The contributions relating to the various aspects of design and performance of trawl boards carried out till 1969 have been considered

A Composite Framework for ESL Textbook Evaluation

Textbook evaluation practices have not been critically examined to determine effectiveness and value in learning-teaching environments and this is probably the main reason why the literature suggests that textbooks selected have been more of a hindrance than a benefit to teaching. The assumption made by the researcher is that since much of the criticism in selection processes of textbooks is directed towards the checklist, which at this moment seems to be the only instrument used in textbook evaluation practices, then there would be a need to re-evaluate the usefulness of the checklist, identify weak areas and then develop a composite framework where the checklist will be supported by complementary instruments, namely the concordance software and the reflective journal. The researcher suggests a 4-phase procedure in the development of the composite framework. Phase 1 tests the Skierso Evaluation Checklist (SEC) for reliability and item difficulty. Phase 2 tests the capabilities of the concordance software (WordSmith Tools 3.0) to provide analysis of the patterns of presentation of vocabulary and structures in textbooks, to determine the extent to which the software will help discriminate between books in a selection process and to determine to what extent the analysis would provide greater illustration to responses required of by items in Section D of the SEC. Phase 3 tests the capabilities of the reflective journal in providing greater illustration to responses to items in Section E (Exercises and Activities) of the SEC. Finally, in Phase 4 the researcher will assemble aspects of the t, 0 complementary components into a framework which has the checklist as its main instrument. This framework will then be tested for reliability and item difficulty. In Phase 1, the findings revealed that while the overall reliability of the SEC was high, the difficulty analysis of items showed Section) and E of the checklist as having the largest number of difficult items. Phase 2 of the study found that the concordance software is capable of many useful functions it textbook evaluation and is able to provide greater illustration, through computation to 6 items in Section D of the SEC. Phase 3 of the investigation revealed that teaching reflections contributed to input that was beneficial to evaluation, especially the item in Section E of the SEC. The composite framework was assembled and created in Phase 4. It was then compared to the mono-instrument procedure (Phase 1) which consisted of the checklist (SEC). The comparison of the two procedures showed the composite framework to be more reliable at 0.9324 reliability as compared to 0.7675 reliability for the SEC as a standalone instrument. The difficulty analysis of items also showed marked improvement when comparisons were made. Only 4 items were considered difficult within the composite framework as opposed to 14 when the SEC was tested as a standalone. This study has provided an alternative to the checklist dominated procedure by proposing a framework which works on the combined effort of 3 distinct instruments, thus providing for much needed triangulation which is actually expected in an exercise as complex as textbook evaluation. The spin-offs to this research are the added value it provides by way of increased awareness of action research in textbook evaluation, to greater emphasis and attention to retrospective evaluation and adaptation. It has also led to the creation of the first Malaysian Corpus of the Language of Textbooks which has approximately 150,000 words. This corpus will expand when it accommodates the language of more textbooks within the school system

Rees algebras and iterated Jacobian duals

Consider the rational map Ψ : [Special characters omitted.] where the fi\u27s are homogeneous forms of the same degree in the homogeneous coordinate ring R = k[ x1,…,xd] of [Special characters omitted.]. Assume that I = (f 1,…,fm) is a height 2 perfect ideal in the polynomial ring R. In this context, the coordinate ring of the graph of Ψ is the Rees algebra of I and the co-ordinate ring of the image of Ψ is the special fiber ring. We study two settings. The first setting is when I is almost linearly presented. Here we study the ideal defining the graph and the image of Ψ. Whenever possible, we also study invariants such as the Castelnuovo-Mumford regularity and the relation type of the graph of Ψ. In the second setting we impose no constraints on the column degrees of the presentation matrix of I, but the number of generators of I is restricted to d + 1 (two more than the dimension of the source of Ψ). For this configuration, we study the image of Ψ. We also introduce a new method, namely iterated\u27\u27 Jacobian duals, to study the graph of Ψ. This is a generalization of the usual Jacobian duals which are often used to describe the graph of Ψ

The Train That Had Wings

The Train That Had Wings presents modern life in Kerala in terms of a shared but tragically compromised humanity. Mukundan dares to look beneath the routines and facades of everyday life in order to probe depth of sin, greed, and hypocrisy but also to rediscover what brings joy and hope. Sixteen short story translations and a critical introduction, offering examples of Mukundan's realistic, existentialist, psychedelic, and parabolic stories, show his range and talent for the very short story. If Hawthorne wrote “twice told tales,” Mukundan writes half-told tales, stories that jump in the middle, stomp around for just a minute, and leap away almost before the reader can settle in. Half-told, but a powerful and infectious half