Thermal Conductivity and Volumetric Specific Heat Measurements of an RTV-655/Polyimide Aerogel Compound Under Varying Temperature

The ability to store cryogenic liquids for long duration space missions is essential to future manned space exploration. Boil-off of cryogens due to incident solar radiation leads to self-pressurization of a cryogenic liquid tank. An ideal tank construction material would have low thermal conductivity and would retain its structural integrity through extreme temperatures. In previous research, a small-scale RTV-655/polyimide aerogel cryogenic liquid storage tank was constructed and tested to assess the performance of the compound material. Further development of RTV-655/polyimide aerogel cryogenic tanks for space applications is contigent upon performing computational studies to optimize the tank design and minimize costly experiments. Morever, computational heat transfer models, specifically models simulating conduction heat transfer through the RTV-655/polyimide aerogel compound, are dependent on accurate, measured thermal conductivity and volumetric specific heat values for the RTV-655/polyimide aerogel compound at the temperatures of interest. Thermal conductivity and volumetric specific heat values of the combination of RTV-655 and polyimide aerogel heave not been published at cryogenic temperatures. The transient plane source method was used to measure the thermal conductivity and volumetric psecific heat for RTV-655, polyimide aerogel, and three volume ratios of the compound at 313K, 295K, 253K, and the cryogenic temperature of 85K

A Bayesian hierarchical model of postlarval delta smelt entrainment: integrating transport, length composition, and sampling efficiency in estimates of loss

Hydrodynamic models have been used to estimate rates of ichthyoplankton transport across marine and estuarine environments and subsequent geographic isolation of a portion of the population (i.e., entrainment). Combining simulated data from hydrodynamic models with data from fish populations can provide more information, including estimates of regional abundance. Entrainment of postlarval delta smelt (Hypomesus transpacificus), a threatened species endemic to California’s Sacramento–San Joaquin Delta, caused by water export operations, was modeled using a Bayesian hierarchical model. The model was fit using data spanning years 1995–2015 from multiple sources: hydrodynamic particle tracking, fish length composition, mark–recapture, and count data from entrainment monitoring. Estimates of the entrainment of postlarval delta smelt ranged from 10 (SD = 23) in May 2006 to 561 791 (SD = 246 423) in May 2002. A simulation study indicated that all model parameters were estimable, but errors in transport data led to biased estimates of entrainment. Using only single data sources rather than integration through hierarchical modeling would have underestimated uncertainty in entrainment estimates or resulted in bias if transport, survival, or sampling efficiency were unaccounted for.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Teaching styles of Australian junior tennis coaches

Game Sense was introduced to Australian tennis during Australian Sports Commission (ASC) national workshops in 1996, prompting tennis coach education providers to emphasise the approach, and its embrace of increased player involvement in the coaching process, in formal coach accreditation literature. This research involving 208 junior development and club professional coaches in self-assessment of their teaching styles, provides insight into the penetration into the everyday coaching practice of one of the central pedagogical tenets of the Game Sense approach – the use of well-considered coach questions to guide the development of players’ technical and tactical game development. Since the ASC workshops in 1996, until this research there has been no assessment of the uptake of the Game Sense approach in Australian tennis. The pedagogical practice of coach-led questions in the Game Sense approach has been referred to as a form of guided discovery. This research used Mosston and Ashworth’s Spectrum of Teaching Styles (2008) (The Spectrum) as a tool through which to investigate the coaching styles of Australian junior tennis coaches, revealing coaches self-identified alignment with the guided discovery practice of coach-led questions (Mosston’s Guided Discovery-Style F). The research found that a practice style (Mosston’s Practice Style-B) was the pedagogical style used most often by the respondents, followed by a more directive or command style (Mosston’s Command Style-A). Guided discovery (Mosston’s Guided Discovery-Style F) was the third most commonly adopted pedagogical practice

Texas 4-H Horse Project Teaching Outlines

pages are numbered to 210, but backs of pages are blank and blanks do not appear in the pdfThis publication contains outlines, study questions and worksheets for 31 lessons on horses and horse care. Topics include feeding management, reproductive systems, marketing, preventing horse theft, and buying and selling horses at public auctions, among others

Population Characteristics, Morphometry, and Growth of Harvested Gray Wolves and Coyotes in Alaska

Few concurrent studies exist of sympatric gray wolf (Canis lupus) and coyote (C. latrans) harvest at far northern latitudes. Moreover, no studies explicitly examine effects of concurrent harvest on phenotypes of wolves and coyotes. We documented changes in sex and age characteristics and morphology of gray wolves and coyotes harvested by hunters near Ptarmigan Lake, east-central Alaska, USA, between 1998 and 2001. We hypothesized that the harvest would result in larger, heavier canids, reduce densities, and increase young to adult ratios in both wolves and coyotes. We generated von Bertalanffy growth curves indicating that wolves and coyotes of both sexes increased in length or weight until 2 or 3 years old. No significant changes in either mean length or weight or length to weight ratios occurred during the 3-year study, except that coyote mean length was longer over the last winter of study. Catch-per-unit effort (CPUE) for wolves ranged from 0.061 to 0.112 killed/day and for coyotes from 0.552 to 0.11 killed/day over the study. CPUE indicated that coyotes but not wolves declined in abundance. Changes in male to female and young to adult ratios did not differ significantly for either canid. We posit that coyote populations were disproportionately affected by the conflation of the severe Arctic environment and sustained harvest. Our findings will be beneficial for managing sympatric canid populations and for understanding demographic responses to density-dependent processes in wolves and coyotes, especially at far northern latitudes.Il existe peu d’études concomitantes sur la récolte du loup gris (Canis lupus) et du coyote (C. latrans) sympatriques dans les hautes latitudes nordiques. Par ailleurs, aucune étude n’examine explicitement les effets de la récolte concomitante sur les phénotypes des loups et des coyotes. Nous avons documenté les changements sur le plan de la morphologie et des caractéristiques du sexe et de l’âge des loups gris et des coyotes récoltés par les chasseurs à proximité du lac Ptarmigan, dans le centre-est de l’Alaska, aux États-Unis, de 1998 à 2001. Nous avons formulé l’hypothèse voulant que la récolte donnerait lieu à des canidés plus gros et plus lourds, réduirait les densités et augmenterait les rapports entre jeunes et adultes, tant chez les loups que chez les coyotes. Nous avons produit des courbes de croissance de von Bertalanffy selon lesquelles la longueur ou le poids des loups et des coyotes des deux sexes augmentait jusqu’à l’âge de deux ou trois ans. Sur le plan de la longueur ou du poids moyen, ou des rapports moyens entre la longueur et le poids, aucun changement important n’a été enregistré pendant l’étude de trois ans, sauf que la longueur moyenne du coyote était plus grande au cours du dernier hiver de l’étude. Pour le loup, la capture par unité d’effort (CPUE) variait de 0,061 à 0,112 bête tuée/jour, tandis que pour le coyote, elle variait de 0,552 à 0,11 bête tuée/jour dans le courant de l’étude. Selon la CPUE, l’abondance des coyotes a chuté, mais pas celle des loups. Pour l’un ou l’autre des canidés, les variations en matière de rapports entre les mâles et les femelles, et entre les jeunes et les adultes n’étaient pas considérables. Nous postulons que les populations de coyotes ont été touchées de manière disproportionnée à la fois par l’environnement arctique rigoureux et par une récolte soutenue. Nos constatations joueront un rôle dans la gestion des populations de canidés sympatriques et dans la compréhension des réponses démographiques aux processus dépendant de la densité chez les loups et les coyotes, surtout dans les hautes latitudes nordiques

Beyond the frame rate: Measuring high-frequency fluctuations with light intensity modulation

Power spectral density measurements of any sampled signal are typically restricted by both acquisition rate and frequency response limitations of instruments, which can be particularly prohibitive for video-based measurements. We have developed a new method called Intensity Modulation Spectral Analysis (IMSA) that circumvents these limitations, dramatically extending the effective detection bandwidth. We demonstrate this by video-tracking an optically-trapped microsphere while oscillating an LED illumination source. This approach allows us to quantify fluctuations of the microsphere at frequencies over 10 times higher than the Nyquist frequency, mimicking a significantly higher frame rate.Comment: 4 pages, 2 figure

Self-identified teaching styles of junior development and club professional tennis coaches in Australia

Many educational theorists believe that there is no 'best' teaching style. A common principle in the discipline of coaching is that coaches should base their teaching style(s) on a number of considerations. These include: the developmental characteristics and individual requirements of the player, as well as the subject matter intent. Apart from anecdotal reports, however, the subject of tennis coaches and teaching styles remains unexplored. It is unknown what teaching styles coaches are employing during coaching sessions and whether these teaching styles are associated with recommended pedagogical principles advocated by scholars. Perhaps this noted lack of information regarding teaching styles is due to the theoretical and practical difficulty of comparing the various terms and interpretations that tennis coaches have in relation to their instructional processes. Arguably, many of these conceptions about teaching styles are not organised in a common theoretical framework but rather exist with the individual interpretations of tennis coaches. It has been anecdotally suggested that the terms used to define teaching styles largely lack consistency and uniformity and are frequently employed interchangeably. Conceivably, this has led to confusion and the absence of a definitive set of concepts and principles reflective of the tennis coaching process and effective practice within it. As diverse learning conditions and experiences are often created by employing different teaching styles, the necessity for coaches to understand and purposefully implement a range of teaching styles to achieve various learning objectives is vital. The requirement for a tennis coach to possess the capacity to employ a range of teaching styles when appropriate is perhaps reliant on a number of considerations. Coaches must be prepared to cater for the diversity of players' learning needs, interests, preferences and developmental readiness or stage of learning. Additionally, tennis involves learning aims from the psychomotor (physical/motor skill), cognitive (decision-making) and affective (enjoyment/motivation) domains. This might suggest the application of specific teaching styles to comprehensively develop each learning area. As no one teaching style encompasses all learning eventualities, an effective coach must have the capability to change, combine and transition between various teaching styles during sessions. This chapter demonstrates how a conceptual model of teaching can be used to evalute and assist in the practice of pedagogical possibilities. It presents the findings of research completed on the self-identified teaching styles of 208 tennis coaches in Australia using Mosston and Ashworth's Spectrum of Teaching Styles (2008) as a basis for identification. Exploring the teaching styles of tennis coaches establishes a baseline of information and provides assistance to identify how the coach facilitates learning. Only an understanding and awareness of coaching behaviours does theorising with regards to current limitations become likely. The possible identification of different features within pedagogical behaviour among tennis coaches in Australia will be particularly crucial in the design of coach education programs and professional development initiatives. These findings may also extend relevance into sports coaching more broadly. Contrary to educational convictions and perceptions, however, the results from this study indicated a different view in relation to the recommended employment of a variety of teaching styles. Results from this study reveal that during their coaching sessions throughout the year, Junior Development and Club Professional tennis coaches predominantly use one teaching style that illicited practice of a specific task described or modeled by the coach. This teaching style is named Practice Style-B. The predominant use of Practice Style-B strongly correlates with the pedagogical principles associated with direct instruction guidelines whereby the coach makes decisions about what the students are learning in addition to how and why they are learning it