Resolving transition metal chemical space: feature selection for machine learning and structure-property relationships

Machine learning (ML) of quantum mechanical properties shows promise for accelerating chemical discovery. For transition metal chemistry where accurate calculations are computationally costly and available training data sets are small, the molecular representation becomes a critical ingredient in ML model predictive accuracy. We introduce a series of revised autocorrelation functions (RACs) that encode relationships between the heuristic atomic properties (e.g., size, connectivity, and electronegativity) on a molecular graph. We alter the starting point, scope, and nature of the quantities evaluated in standard ACs to make these RACs amenable to inorganic chemistry. On an organic molecule set, we first demonstrate superior standard AC performance to other presently-available topological descriptors for ML model training, with mean unsigned errors (MUEs) for atomization energies on set-aside test molecules as low as 6 kcal/mol. For inorganic chemistry, our RACs yield 1 kcal/mol ML MUEs on set-aside test molecules in spin-state splitting in comparison to 15-20x higher errors from feature sets that encode whole-molecule structural information. Systematic feature selection methods including univariate filtering, recursive feature elimination, and direct optimization (e.g., random forest and LASSO) are compared. Random-forest- or LASSO-selected subsets 4-5x smaller than RAC-155 produce sub- to 1-kcal/mol spin-splitting MUEs, with good transferability to metal-ligand bond length prediction (0.004-5 {\AA} MUE) and redox potential on a smaller data set (0.2-0.3 eV MUE). Evaluation of feature selection results across property sets reveals the relative importance of local, electronic descriptors (e.g., electronegativity, atomic number) in spin-splitting and distal, steric effects in redox potential and bond lengths.Comment: 43 double spaced pages, 11 figures, 4 table

Principles of Fast Fission

In the thermal reactor a moderator of some sort is used to slow down the neutrons so that fission can take place at thermal speeds. In the case of a reactor using U-235 along with U-238, it is just possible to produce a self-sustaining chain reaction. This is because U-238 is only fissionable by high energy neutrons and the inelastic scattering cross section of U-238 is dominant at high energies. Therefore the fast neutrons produced on fission have a very small chance of producing another fission

Constructing the Cool Wall: A Tool to Explore Teen Meanings of Cool

This paper describes the development and exploration of a tool designed to assist in investigating ‘cool’ as it applies to the design of interactive products for teenagers. The method involved the derivation of theoretical understandings of cool from literature that resulted in identification of seven core categories for cool, which were mapped to a hierarchy. The hierarchy includes having of cool things, the doing of cool activities and the being of cool. This paper focuses on a tool, the Cool Wall, developed to explore one specific facet of the hierarchy; exploring shared understanding of having cool things. The paper describes the development and construction of the tool, using a heavily participatory approach, and the results and analysis of a study carried out over 2 days in a school in the UK. The results of the study both provide clear insights into cool things and enable a refined understanding of cool in this context. Two additional studies are then used to identify potential shortcomings in the Cool Wall methodology. In the first study participants were able to populate a paper cool wall with anything they chose, this revealed two potential new categories of images and that the current set of images covered the majority of key themes. In the second study teenagers interpretations of the meaning of the images included in the Cool Wall were explored, this showed that the majority of meanings were as expected and a small number of unexpected interpretations provided some valuable insights

EVALUATION OF EFFECTIVE MICROORGANISMS (EM) TECHNOLOGY IN MAIZE (Zea mays L.) GROWTH, DEVELOPMENT AND YIELD IN MOROGORO TANZANIA

The field experiment was conducted at Tushikamane Centre Kilakala, Morogoro Tanzania to investigate the effect of EM technology on maize (Zea mays L.) growth, development and yield. Maize is a major cereal consumed; over 80% of population depends on maize for food in Tanzania. Low soil fertility, insect pests and diseases are among the primary constraints in maize production. This is due to continuous cultivation without fertilizing the soil, poor and lack of proper measures to control pest and diseases. Most farmers in both rural and urban areas of Tanzania are not aware with the use of organic fertilizers especially the EM (Effective Microorganism) technology in agriculture to increase crop yield without the use of agricultural chemicals or artificial fertilizers, the method of farming is inexpensive, capable of producing high-quality products, high yield produces and preserving the environment. Therefore, this research work mainly aimed at studying the efficiency of EM technology on maize (Zea mays L.) crop performance in the field. Five treatments comprising of EM technology EM-Bokashi, Bokashi and EM-A, EM-FPE and EM-5, combination of Bokashi, EM-A, EMFPE and EM5, and absolute control were compared in a randomized complete block design with three replications. Bokashi leaves (3.7%N) at 1851.9kg/ha, 200 mls of EMA mixed with water to make a 2L solution, EMFPE and EM5 were mixed with water at 200mls to get a 2L solution which was sprayed thrice a week scheduled for application. Three weeks were scheduled for application of EM. Application of EM-Bokashi produced an average yield of 3.06 tonha-1, EM-Bokashi and EM-A produced grain yield of 3.24 tonha-1, EMFPE and EM-5 produced 3.11 tonha-1 and, application of all EM-Bokashi, EM-A, EMFPE and EM-5 produced grain yield of 3.51 tonha-1, while absolute control produced 2.12 tonha-1. Application of EM improved maize crop yield

Feasibility of recruitment to an oral dysplasia trial in the United Kingdom

Background: Oral epithelial dysplasia (OED) has a malignant potential. Therapeutic options for OED remain both limited and without good evidence. Despite surgery being the most common method of treating OED, recurrence and potentially significant morbidity remain problematic. Consequently, there has been much interest in non-surgical treatments for OED. Cyclo-oxygenase (COX) up-regulation is known to occur in the dysplasia-carcinoma sequence and evidence now exists that COX-2 is a prognostic marker of malignant transformation in OED. COX-inhibitors are therefore considered a potential therapeutic strategy for treating this condition. We aimed to provide both proof of principal evidence supporting the effect of topical COX inhibition, and determine the feasibility of recruitment to an OED chemoprevention trial in the UK. Methods: Recruitment of 40 patients with oral leukoplakia to 4 study arms was planned. The total daily dose of Aspirin would increase in each group and be used in the period between initial diagnostic and follow-up biopsies. Results: During the 15-month recruitment period, 15/50 screened patients were eligible for recruitment, and 13 (87%) consented. Only 1 had OED diagnosed on biopsy. 16 patients were intolerant of, or already taking Aspirin and 16 patients required no biopsy. Initial recruitment was slow, as detection relied on clinicians identifying potentially eligible patients. Pre-screening new patient letters and directly contacting patients listed for biopsies improved screening of potentially eligible patients. However, as the incidence of OED was so low, it had little impact on trial recruitment. The trial was terminated, as recruitment was unlikely to be achieved in a single centre. Conclusion: This feasibility trial has demonstrated the low incidence of OED in the UK and the difficulties in conducting a study because of this. With an incidence of around 1.5/100,000/year and a high proportion of those patients already taking or intolerant of Aspirin, a large multi-centred trial would be required to fulfil the recruitment for this study. The ability of topical non-steroidal anti-inflammatory drugs to modify COX and prostaglandin expression remains an important but unanswered question. Collaboration with centres in other parts of the world with higher incidences of the disease may be required to ensure adequate recruitment. ISRCTN: 31503555

Promoting Airport Walking: A Guide

A study found that signs placed in the Hartsfield-Jackson Atlanta International Airport to promote passengers walking to airport gates rather than taking shuttles resulted in several hundred more passengers a day choosing to walk (ceiling-mounted infrared sensors were used to count travelers entering and exiting the study location). The project was supported by Kresge and the Centers for Disease Control and Prevention. The study also produced a guide, "Promoting Airport Walking," intended primarily for airport managers who want their airports to encourage healthy habits and improve customer experiences

the Summer Institute of Musical Art Presents An Evening of Chamber Music

https://mds.marshall.edu/music_perf/1069/thumbnail.jp

In the dark – designing navigation for a haptic theatre experience

We describe the ongoing work of a collaborative theatre project, in which blind and sighted members of an interdisciplinary team are working on the creation of an immersive and accessible theatre experience. The theatre experience is set in pitch dark, and uses audio and haptic ubiquitous technologies to guide both blind and sighted members of the audience. During two sessions which explored the use of enactive navigation in the dark space, participants were able to locate areas of interest within the dark, using enactive explorative navigation, and some participants described this as a ‘dense’ experience