Signatures of the Martian rotation parameters in the Doppler and range observables

The position of a Martian lander is affected by different aspects of Mars' rotational motions: the nutations, the precession, the length-of-day variations and the polar motion. These various motions have a different signature in a Doppler observable between the Earth and a lander on Mars' surface. Knowing the correlations between these signatures and the moments when these signatures are not null during one day or on a longer timescale is important to identify strategies that maximize the geophysical return of observations with a geodesy experiment, in particular for the ones on-board the future NASA InSight or ESA-Roscosmos ExoMars2020 missions. We provide first-order formulations of the signature of the rotation parameters in the Doppler and range observables. These expressions are functions of the diurnal rotation of Mars, the lander position, the planet radius and the rotation parameter. Additionally, the nutation signature in the Doppler observable is proportional to the Earth declination with respect to Mars. For a lander on Mars close to the equator, the motions with the largest signature in the Doppler observable are due to the length-of-day variations, the precession rate and the rigid nutations. The polar motion and the liquid core signatures have a much smaller amplitude. For a lander closer to the pole, the polar motion signature is enhanced while the other signatures decrease. We also numerically evaluate the amplitudes of the rotation parameters signature in the Doppler observable for landers on other planets or moons.Comment: 30 pages 7 figures, In press PS

Selected Cases on the Continuum of First Nations Learning

Each of the articles in this dissertation addresses a policy or theoretical issue at a different point on the learning continuum. Chapter 2, First Nations Early Learning and Child Care in Canada, examines federal policy specific to First Nations early learning and child care (ELCC). This article contributes to our understanding of ELCC by examining the historical role and relationship of the federal government in the financing and delivery of ELCC, outlining the current state of federal early learning policy related to First Nations, and presenting national data on First Nations ELCC to assess how it can inform policy and data needs. The third chapter, Standardized Testing and First Nations Schools: A Case Study examines the impact of the use of provincial standardized testing in an on-reserve elementary school in Ontario. Using a case study approach, the perspectives of the school administration and teachers are explored. The research questions include: 1) Why might an Indigenous school choose to implement a regional standardized assessment? 2) How does this impact the schools’ ability to provide a culturally based education? 3) What challenges does a First Nations school face in implementing a standardized assessment? Chapter 4, Educational Expectations of First Nations Applicants to Postsecondary, utilizes data from a large-scale Canadian survey to look at the relationship between personal, family, community, and academic factors and the educational expectations of First Nations learners. Expectations are a fundamental part of the attainment process, and have been shown to be a key predictor of eventual educational attainment. Most theories of educational expectations, however, have been developed based on the experiences of non-Indigenous youth. The concluding chapter discusses policy implications and future research

Editorial

Listening. Connecting. Creating safe spaces to work and play. Building community. As we begin to emerge from the ravages of the Pandemic, and as reporting about racial violence and the aftermath of the attack on the Capitol remain front page news, such ideas seem to have slipped from our grasp. A great weariness weighs on us, as we long for a respite from assaults on our physical health, on our emotional well-being, and on our ability to function as members of a civil society. We long to move, to play, to enjoy the company of others, to share our thoughts, and to feel safe and at peace. Perhaps some respite from this constant state of fatigue and anxiety can be found in three essays published in this year’s edition of SPACE. Each offers a glimpse at the possible. Themes emerge that cause the authors’ ideas to resonate with each other in a way that seems planned, but which converged organically. Our selected essays address issues surrounding education, which also seems fitting in this time of distance learning. Images of teachers speaking to black squares on computer screens challenge us to ask: what can we do to help students learn while also supporting their physical and emotional well-being? How can such simple acts as listening, connecting, creating safe spaces and building community enhance the way young people learn? As we revisit these elemental ideas, can we grow into new ways of teaching and learning that cause us to look back at these challenges and thank them for the lessons they contain? As we reflect on our collective weariness of violence and incivility, can we begin to find ways to reconstruct positive social interaction—even if the steps toward that ideal might seem too small to make a difference? Youla Bekiaris and Randall O’Neill, who recently became licensed to teach history and social studies in Illinois, write about their experience doing service-learning at the Youth Services Program at the Center on Halsted. This is a safe space for LGBTQ youth in Chicago, many of whom have experienced violence and homelessness. The authors, who engaged in the simple act of preparing and serving meals at the Center, write about the importance of learning firsthand about the experiences of these young people in order to become better advocates for the LGBTQ students they teach. Dominique Modory shares her experiences teaching a hip-hop dance class to elementary school children. By incorporating Gloria Ladson-Billings’ teachings about culturally relevant pedagogy, Modory explores the natural extension of this approach to the larger issues of social justice and inequity she anticipates encountering in her future career as an elementary school teacher. Carolyn Crost and Kimberly Maljak share their research findings about how using a Social Ecological Model (SEM) can help educators discover the ways the larger community influences the physical health of school children. Although the authors discovered that the community where they conducted their research provides multiple supports for the well-being of the people who live there, they do suggest ways to use the SEM model in order to identify and provide those supports in communities where they are lacking. Serving food and listening. Learning from children whose culture is different from our own. Looking at how the larger community sends powerful messages to people who live there. These are the small steps and hopeful moments our writers in this edition of SPACE offer us. We hope their ideas inspire you

Optical Studies of Twenty Longer-Period Cataclysmic Binaries

We obtained time-series radial velocity spectroscopy of twenty cataclysmic variable stars, with the aim of determining orbital periods P_orb. All of the stars reported here prove to have P_orb > 3.5 h. For sixteen of the stars, these are the first available period determinations, and for the remaining four (V709 Cas, AF Cam, V1062 Tau, and RX J2133+51) we use new observations to improve the accuracy of previously-published periods. Most of the targets are dwarf novae, without notable idiosyncracies. Of the remainder, three (V709 Cas, V1062 Tau, and RX J2133+51) are intermediate polars (DQ Her stars); one (IPHAS 0345) is a secondary-dominated system without known outbursts, similar to LY UMa; one (V1059 Sgr) is an old nova; and two others (V478 Her and V1082 Sgr) are long-period novalike variables. The stars with new periods are IPHAS 0345 (0.314 d); V344 Ori (0.234 d); VZ Sex (0.149 d); NSVS 1057+09 (0.376 d); V478 Her (0.629 d); V1059 Sgr (0.286 d); V1082 Sgr (0.868 d); FO Aql (0.217 d); V587 Lyr (0.275 d); V792 Cyg (0.297 d); V795 Cyg (0.181 d); V811 Cyg (0.157 d); V542 Cyg (0.182 d); PQ Aql (0.247 d); V516 Cyg (0.171 d); and VZ Aqr(0.161 d). Noteworthy results on individual stars are as follows. We see no indication of the underlying white dwarf star in V709 Cas, as has been previously claimed; based on the non-detection of the secondary star, we argue that the system is farther away that had been thought and the white dwarf contribution is probably negligible. V478 Her had been classified as an SU UMa-type dwarf nova, but this is incompatible with the long orbital period we find. We report the first secondary-star velocity curve for V1062 Tau. In V542 Cyg, we find a late-type contribution that remains stationary in radial velocity, yet the system is unresolved in a direct image, suggesting that it is a hierarchical triple system.Comment: P.A.S.P., in press. 34 pages and 8 figure

Cure kinetics characterization and monitoring of an epoxy resin using DSC, Raman spectroscopy, and DEA

The use of thick sections of fiber-reinforced polymers (FRPs) is increasing for numerous industrial applications such as wind turbine blades. In situ cure monitoring is very important to directly observe the cure process of FRPs during the manufacturing process. In this work, Raman spectroscopy and dielectric analysis (DEA) are investigated for in situ cure monitoring of an epoxy resin. The cure behavior is first characterized using differential scanning calorimetry (DSC) as a baseline comparison, and the best-fit phenomenological reaction model is determined to describe the cure behavior of the epoxy resin as well as the kinetic parameters. The relationship between Tg and degree of cure is also established. The degree of cure obtained from Raman spectroscopy and DEA under isothermal conditions is compared to that obtained from DSC. A good agreement is observed among the three methods, supporting the potential of these in situ cure monitoring methods during manufacturing. An implementation plan for in-plant monitoring is also discussed