Comment on the choice of time in a two-component formulation of the Wheeler--DeWitt equation

The two-component formalism in quantum cosmology is revisited with a particular emphasis on the identification of time. Its relation with the appearance of imaginary eigenvalues is established. It is explicitly shown how a good choice of the global time prevents this peculiarity.Comment: 8 pages; version accepted for publication in Int. J. Mod. Phys.

Taken by strum: ukuleles and participatory music-making in Hamilton, Aotearoa/New Zealand

Ethnographic study of ukulele playing in Hamilton, N

Improved Spacecraft Materials for Radiation Shielding

In the execution of this proposal, we will first examine current and developing spacecraft materials and evaluate their ability to attenuate adverse biological mutational events in mammalian cell systems and reduce the rate of cancer induction in mice harderian glands as a measure of their protective qualities. The HZETRN code system will be used to generate a database on GCR attenuation in each material. If a third year of funding is granted, the most promising and mission-specific materials will be used to study the impact on mission cost for a typical Mars mission scenario as was planned in our original two year proposal at the original funding level. The most promising candidate materials will be further tested as to their transmission characteristics in Fe and Si ion beams to evaluate the accuracy of the HZETRN transmission factors. Materials deemed critical to mission success may also require testing as well as materials developed by industry for their radiation protective qualities (e.g., Physical Sciences Inc.) A study will be made of designing polymeric materials and composite materials with improved radiation shielding properties as well as the possible improvement of mission-specific materials

A Universal Design for Success: A Mixed-methods Case Study of a First-year BScN Course

No single universal learner type exists, however historically, pedagogical practices in higher education have focused on meeting the learning needs of an average or typical student. The purpose of this study was to describe the manner and extent in which a course, designed using Universal Design for Learning (UDL) principles, provided an inclusive learning environment to a diverse population of first-year baccalaureate nursing students. Co-instructors redesigned a large in-person and place-based course using theoretical and structural principles of UDL to remove potential learning barriers and promote authentic inclusion of all students. A convergent mixed methods descriptive case study design was used to gather qualitative and quantitative data. A purposive convenience sample was drawn from a class of 223 full and part time nursing students. Qualitative data were collected through an end of semester focus group interview (n=12) and research team meetings. Quantitative data collection involved using the Inclusive Teaching Strategies Inventory-Students survey questionnaire (Gawronski, et al., 2016) at course completion (n=32), and document review of final grades (n= 206). The use of UDL principles in the design and teaching supported the needs and abilities of learners with a variety of learning preferences and experience. Students experienced a more inclusive environment with fewer barriers to learning. Large in-person and place-based post-secondary courses designed using the key tenets of UDL successfully support inclusivity of the needs of learners with diverse backgrounds, abilities, and preferences, by proactively reducing barriers in the learning environment. Résumé Il existe plusieurs types d’apprenantes, mais historiquement, les pratiques pédagogiques en formation de niveau supérieur ont été axées sur la satisfaction des besoins d’apprentissage d’une étudiante moyenne ou typique. Le but de cette étude était de décrire la manière et la mesure dans laquelle un cours, conçu selon les principes de la conception universelle pour l’apprentissage (CUA), offrait un environnement d’apprentissage inclusif à une population diversifiée d’étudiantes de première année au baccalauréat en sciences infirmières. Les co-enseignantes ont repensé un cours donné à un vaste groupe en présentiel, en utilisant les principes théoriques et structurels de la CUA pour éliminer les obstacles potentiels à l’apprentissage et promouvoir l’inclusion authentique de toutes les étudiantes. Une combinaison d’une approche mixte et d’étude de cas descriptive a été utilisée pour recueillir des données qualitatives et quantitatives. Un échantillon de convenance a été tiré d’une classe de 223 étudiantes en sciences infirmières inscrites à temps plein ou à temps partiel. Les données qualitatives ont été recueillies lors d’une entrevue de groupe en fin de semestre (n=12) et lors de réunions de l’équipe de recherche. La collecte de données quantitatives impliquait l’utilisation du questionnaire d’enquête Inclusive Teaching Strategies Inventory-Students (inventaire des stratégies inclusives d’enseignement — étudiantes; Gawronski et al., 2016) à la fin du cours (n = 32) ainsi que l’examen des documents de notes finales (n = 206). Les principes de la CUA appliqués à la conception et à l’enseignement ont soutenu les besoins et les capacités des apprenantes détenant une variété de préférences et d’expériences d’apprentissage. Les étudiantes ont connu un environnement plus inclusif avec moins d’obstacles à l’apprentissage. Les grands cours postsecondaires en présentiel conçus à l’aide des principes clés de la CUA soutiennent avec succès l’inclusion des besoins des apprenantes ayant des expériences antérieures différentes, des capacités et des préférences diverses, tout en réduisant de manière proactive les obstacles dans l’environnement d’apprentissage

Multi-Functional BN-BN Composite

Multifunctional Boron Nitride nanotube-Boron Nitride (BN-BN) nanocomposites for energy transducers, thermal conductors, anti-penetrator/wear resistance coatings, and radiation hardened materials for harsh environments. An all boron-nitride structured BN-BN composite is synthesized. A boron nitride containing precursor is synthesized, then mixed with boron nitride nanotubes (BNNTs) to produce a composite solution which is used to make green bodies of different forms including, for example, fibers, mats, films, and plates. The green bodies are pyrolized to facilitate transformation into BN-BN composite ceramics. The pyrolysis temperature, pressure, atmosphere and time are controlled to produce a desired BN crystalline structure. The wholly BN structured materials exhibit excellent thermal stability, high thermal conductivity, piezoelectricity as well as enhanced toughness, hardness, and radiation shielding properties. By substituting with other elements into the original structure of the nanotubes and/or matrix, new nanocomposites (i.e., BCN, BCSiN ceramics) which possess excellent hardness, tailored photonic bandgap and photoluminescence, result

SMOS soil moisture product validation in croplands

A validation campaign has been carried out to evaluate the Level 2 Soil Moisture (SM) product (version 5.51) given by the European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) satellite in the Pampean Region of Argentina. The study region was selected because it is a plain, avoiding topography problems, with an SMOS nominal land use class (low vegetation crops, 1-2m height). Transects of ground SM measurements were collected at 5-cm and 6-cm depth using Delta-T ThetaProbe ML2x and Stevens Hydra Probe II SM sensors, respectively. The volumetric measurements were calibrated using gravimetric and bulk density data collected at the same time as the SM sensor measurements. The SM transects covered ISEA-grid SMOS nodes over four extensive agricultural areas with prevalence of soy crops (site 1: -32.982N, -62.505E; site 2: -32.510N, -62.788E; site 3: -32.024N, -63.692E; and site 4: -37.315N, -58.868E, WGS84). The validation sites were selected taking as reference the locations of permanent SM stations property of the Argentinean Comisión Nacional de Actividades Espaciales (CONAE, National Commission of Space Activities), Instituto Nacional de Tecnología Agropecuaria (INTA, National Institute of Farming Technology) and Instituto de Hidrología de Llanuras (IHLLA, Plain Hydrology Institute). Therefore, additionally to validate the SMOS SM product with the ground data collected during the experimental campaign, the measurements are useful to evaluate the station SM data reliability at the SMOS spatial resolution with the aim of using station data series as reference to test different versions of the SMOS SM product. Previously to the campaign, SMOS SM data variability, ESA Globcover land use classification, soil edaphic properties, water bodies and topography were analyzed around the station locations to select the best sites and the experimental methodology. Temperature vegetation dryness index (TVDI) temporal and spatial variability was also studied at the sites. Additionally, transects of land surface temperature were carried out with Cimel Electronique CE312 6-band radiometers concurrently with thermal-infrared (TIR) satellite overpasses. In previous works, we studied the dependence of land surface emissivities on SM. The analysis of concurrent TIR and SM data make possible to evaluate the utility of the SMOS SM product to improve land surface emissivities and temperature determinations from satellite, giving an added value to the research

Thin-shell wormholes in Einstein-Maxwell theory with a Gauss-Bonnet term

We study five dimensional thin-shell wormholes in Einstein-Maxwell theory with a Gauss-Bonnet term. The linearized stability under radial perturbations and the amount of exotic matter are analyzed as a function of the parameters of the model. We find that the inclusion of the quadratic correction substantially widens the range of possible stable configurations, and besides it allows for a reduction of the exotic matter required to construct the wormholes.Comment: 13 pages, 6 figures; v2: minor changes and new references added. Accepted for publication in General Relativity and Gravitatio