Beyond direct simulation Monte Carlo (DSMC) modelling of collision environments

Direct simulation Monte Carlo (DSMC) models have been successfully adopted and adapted to describe gas flows in a wide range of environments since the method was first introduced by Bird in the 1960s. We propose a new approach to modelling collisions between gas-phase particles in this work - operating in a similar way to the DSMC model, but with one key difference. Particles move in a mean field, generated by all previously propagated particles, which removes the requirement that all particles be propagated simultaneously. This yields a significant reduction in computation effort and lends itself to applications for which DSMC becomes intractable, such as when a species of interest is only a minor component of a large gas mixture

The use of and responses to a letter writing process to increase communicative competence in ESL learners : a thesis presented in fulfilment of the requirements for the degree of Master of Arts in Second Language Teaching at Massey University, Palmerston North, New Zealand

This thesis is a study of how a teacher can help learners to increase communicative competence through an interactive letter writing process. The study was triggered in response to a specific group of immigrants' apparent improvement in not only their written English, but also in their ability to communicate more confidently with native speakers after using the letter writing process as the consistent medium of instruction. The research seeks to describe and ascertain the effectiveness of the letter writing process to enable the learners to become more communicatively competent. In order to do this, it explores some of the inherent underlying conditions to which improvement in communicative competence is attributed, and how these are incorporated into the letter writing process. The research identifies the areas to which the learners attribute their improvement in their communicative language ability. It also outlines the conditions needed to set up this process, the strategies used, and the ways in which the letter writing is extended into an oral activity. The research is in the action research tradition with a qualitative orientation. The researcher focuses on letters written weekly by the teacher to the learners over a one-year language course. The following strategies were explored in relation to the learners' perception of their improvement in communicative competence and their actual improvement in their writing ability: the self disclosure of the teacher in the letter, the introduction of language used in everyday conversation in New Zealand, and the interaction with native English speaking conversation assistants. The results of the research suggest that the instructional material, the weekly letter, provided the authenticity, relevance, interest and enjoyment to enable learners to maintain high levels of motivation and increase the level of output and accuracy of their writing. Through analysis of the learners' letters, there is a significant increase in not only the length of the letters, but also an increase in sentence length, the use of idioms and colloquial language, and a decrease in tense error. Through an analysis of written questionnaires and taped interviews, learners clearly identify the letters as significantly contributing to not only an increase in their linguistic performance, but also to their increased cultural awareness and confidence with native English speakers. The research highlights the potency of teacher/learner interaction and invites further research into the influence of the teacher's personality and teaching style, as well as the effectiveness of the letter writing process in the hands of other teachers

Anthesis, pollination and fruitset in Pinot Noir

Aspects of pollination and resulting fruitset in Vitis vinifera cv. Pinot Noir were investigated in a cool climate wine area of Southern Tasmania (Australia). Changes in the appearance of the stigmatic surface and pollen grains were recorded using environmental scanning electron microscopy (ESEM). Flowers with the calyptra intact (before capfall), showed an apparently turgid stigmatic surface and pollen grains present on the surface were slender and elongated (L/D 35 μm/15 μm). Stigmas had a more flaccid appearance after capfall and pollen grains were more spherical and less elongated in shape (L/D 28 μm/20 μm). Pollen was visible on the stigma surface before capfall, indicating that anthesis occurred whilst the calyptra was in place. Pollen viability tests showed that the pollen was already viable at this stage, and it remained viable until after the flower had been open for several days. Fluorescence micrographs showed no evidence of pollen tube growth until after capfall. Flowers covered by waxed paper bags to eliminate external pollen and thus allow only self-pollination, gave a percentage fruitset equal to that of flowers where external pollen was not excluded. Results indicate that Pinot Noir can be self-pollinated, and that while anthesis commences prior to capfall, fertilisation does not proceed until after capfall.

AMPDB: the Arabidopsis Mitochondrial Protein Database

The Arabidopsis Mitochondrial Protein Database is an Internet-accessible relational database containing information on the predicted and experimentally confirmed protein complement of mitochondria from the model plant Arabidopsis thaliana (http://www.ampdb.bcs.uwa.edu.au/). The database was formed using the total non-redundant nuclear and organelle encoded sets of protein sequences and allows relational searching of published proteomic analyses of Arabidopsis mitochondrial samples, a set of predictions from six independent subcellular-targeting prediction programs, and orthology predictions based on pairwise comparison of the Arabidopsis protein set with known yeast and human mitochondrial proteins and with the proteome of Rickettsia. A variety of precomputed physical–biochemical parameters are also searchable as well as a more detailed breakdown of mass spectral data produced from our proteomic analysis of Arabidopsis mitochondria. It contains hyperlinks to other Arabidopsis genomic resources (MIPS, TIGR and TAIR), which provide rapid access to changing gene models as well as hyperlinks to T-DNA insertion resources, Massively Parallel Signature Sequencing (MPSS) and Genome Tiling Array data and a variety of other Arabidopsis online resources. It also incorporates basic analysis tools built into the query structure such as a BLAST facility and tools for protein sequence alignments for convenient analysis of queried results

Beyond the Western front:targeted proteomics and organelle abundance profiling

The application of westerns or immunoblotting techniques for assessing the composition, dynamics, and purity of protein extracts from plant material has become common practice. While the approach is reproducible, can be readily applied and is generally considered robust, the field of plant science suffers from a lack of antibody variety against plant proteins. The development of approaches that employ mass spectrometry to enable both relative and absolute quantification of many hundreds of proteins in a single sample from a single analysis provides a mechanism to overcome the expensive impediment in having to develop antibodies in plant science. We consider it an opportune moment to consider and better develop the adoption of multiple reaction monitoring (MRM)-based analyses in plant biochemistry

Growth in Public Interest and Scientific Research on Kinesiology Taping

Kinesiology taping has grown in popularity, though there are a number of unsubstantiated claims made by some kinesiology taping advocates. An investigation was conducted into trends in general and scientific interest in kinesiology taping. Data in the public domain (Google Trends and Google Scholar data) indicated significant growth of interest both in terms of public search queries and scientific publications relevant to kinesiology taping. Cyclical trends in interest relevant to kinesiology taping were identified. Segmented regression indicated some of the growth in interest in kinesiology taping may be attributed to exposure of spectators of the Olympic Games to kinesiology taping in athletes. Despite substantial growth in research on kinesiology taping there remain unsubstantiated claims

Coulomb crystal mass spectrometry in a digital ion trap

We present a mass spectrometric technique for identifying the masses and relative abundances of Coulomb-crystallized ions held in a linear Paul trap. A digital radio-frequency wave form is employed to generate the trapping potential, as this can be cleanly switched off, and static dipolar fields are subsequently applied to the trap electrodes for ion ejection. Close to 100% detection efficiency is demonstrated for Ca+ and CaF+ ions from bicomponent Ca+ − CaF+ Coulomb crystals prepared by the reaction of Ca+ with CH3F. A quantitative linear relationship is observed between ion number and the corresponding integrated time-of-flight (TOF) peak, independent of the ionic species. The technique is applicable to a diverse range of multicomponent Coulomb crystals—demonstrated here for Ca+ − NH3+ − NH4+ and Ca+ − CaOH+ − CaOD+ crystals—and will facilitate the measurement of ion-molecule reaction rates and branching ratios in complicated reaction systems

A variable time step self-consistent mean field DSMC model for three-dimensional environments

A self-consistent mean field direct simulation Monte Carlo (SCMFD) algorithm was recently proposed for simulating collision environments for a range of one-dimensional model systems. This work extends the one-dimensional SCMFD approach to three dimensions and introduces a variable time step (3D-vt-SCMFD), enabling the modeling of a considerably wider range of different collision environments. We demonstrate the performance of the augmented method by modeling a varied set of test systems: ideal gas mixtures, Poiseuille flow of argon, and expansion of gas into high vacuum. For the gas mixtures, the 3D-vt-SCMFD method reproduces the properties (mean free path, mean free time, collision frequency, and temperature) in excellent agreement with theoretical predictions. From the Poiseuille flow simulations, we extract flow profiles that agree with the solution to the Navier–Stokes equations in the high-density limit and resemble free molecular flow at low densities, as expected. The measured viscosity from 3D-vt-SCMF is ∼15% lower than the theoretical prediction from Chapman–Enskog theory. The expansion of gas into vacuum is examined in the effusive regime and at the hydrodynamic limit. In both cases, 3D-vt-SCMDF simulations produce gas beam density, velocity, and temperature profiles in excellent agreement with analytical models. In summary, our tests show that 3D-vt-SCMFD is robust and computationally efficient, while also illustrating the diversity of systems the SCMFD model can be successfully applied to

The<i> Arabidopsis</i> cytosolic proteome:the metabolic heart of the cell

The plant cytosol is the major intracellular fluid that acts as the medium for inter-organellar crosstalk and where a plethora of important biological reactions take place. These include its involvement in protein synthesis and degradation, stress response signaling, carbon metabolism, biosynthesis of secondary metabolites, and accumulation of enzymes for defense and detoxification. This central role is highlighted by estimates indicating that the majority of eukaryotic proteins are cytosolic. Arabidopsis thaliana has been the subject of numerous proteomic studies on its different subcellular compartments. However, a detailed study of enriched cytosolic fractions from Arabidopsis cell culture has been performed only recently, with over 1,000 proteins reproducibly identified by mass spectrometry. The number of proteins allocated to the cytosol nearly doubles to 1,802 if a series of targeted proteomic characterizations of complexes is included. Despite this, few groups are currently applying advanced proteomic approaches to this important metabolic space. This review will highlight the current state of the Arabidopsis cytosolic proteome since its initial characterization a few years ago