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Conversational repair has been found to play a fundamental role in the acquisition of language. This paper describes existing research on conversational repair and its relationship to language learning, whether a first language or a second language, as well as its relevance to augmentative and alternative communication (AAC). A case is made for incorporating prompts to repair in conversation-based language interventions with children learning to use AAC. We argue that interventions targeting linguistic complexity should encourage self-repair in conversation in order to develop linguistic and operational competency as well as increase automaticity when using AAC. Clinical implications and directions for future research are discussed.

For children with complex communication needs in the early stages of language development, access to appropriate vocabulary provides a means for social interaction and participation, and the foundation for the acquisition of grammar and other language related skills. While numerous resources are available to support decision making for speakers of English, there is a pressing need to rapidly expand such resources for other languages. Spanish is the official language in 20 countries, and in other countries (e.g., United States) Spanish-speaking communities represent a substantial proportion of the population. The aim of this study was to produce a developmentally-relevant word list for use by Spanish-speaking children in the early stages of language development. The list was developed from an analysis of overlap between published and validated lists of words produced by young Spanish speaking children with typical development. The list includes a wide range of word classes and semantic categories and is proposed as a tool to assist professionals, families and software developers in the process of selecting an initial lexicon for children who require AAC and are learning Spanish. Implications of our findings for vocabulary selection and future research directions are discussed.

This study constrains the lower bound of the scattering phase function of Martian water ice clouds (WICs) through the implementation of a new observation aboard the Mars Science Laboratory (MSL). The Phase Function Sky Survey (PFSS) was a multiple pointing all-sky observation taken with the navigation cameras (Navcam) aboard MSL. The PFSS was executed 35 times during the Aphelion Cloud Belt (ACB) season of Mars Year 34 over a solar longitude range of L_s=61.4{\deg}-156.5{\deg}. Twenty observations occurred in the morning hours between 06:00 and 09:30 LTST, and 15 runs occurred in the evening hours between 14:30 and 18:00 LTST, with an operationally required 2.5 hour gap on either side of local noon due the sun being located near zenith. The resultant WIC phase function was derived over an observed scattering angle range of 18.3{\deg} to 152.61{\deg}, normalized, and compared with 9 modeled phase functions: seven ice crystal habits and two Martian WIC phase functions currently being implemented in models. Through statistical chi-squared probability tests, the five most probable ice crystal geometries observed in the ACB WICs were aggregates, hexagonal solid columns, hollow columns, plates, and bullet rosettes with p-values greater than or equal to 0.60, 0.57,0.56,0.56, and 0.55, respectively. Droxtals and spheres had p-values of 0.35, and 0.2, making them less probable components of Martian WICs, but still statistically possible ones. Having a better understanding of the ice crystal habit and phase function of Martian water ice clouds directly benefits Martian climate models which currently assume spherical and cylindrical particles., Comment: Accepted Manuscript by Planetary and Space Science

1. INTRODUCTIONThe Mars Science Laboratory (MSL) is located in Gale Crater (4.5°S, 137.4°E), and has been performing cloud observations for the entirety of its mission, since its landing in 2012 [eg. 1,2,3]. One such observation is the Phase Function Sky Survey (PFSS), developed by Cooper et al [3] and instituted in Mars Year (MY) 34 to determine the scattering phase function of Martian water-ice clouds. The clouds of interest form during the Aphelion Cloud Belt (ACB) season (Ls=50°-150°), a period of time during which there is an increase in the formation of water-ice clouds around the Martian equator [4]. The PFSS observation was also performed during the MY 35 ACB season and the current MY 36 ACB season.Following the MY 34 ACB season, Mars experienced a global dust storm which lasted from Ls~188° to Ls~250° of that Mars year [5]. Global dust storms are planet-encircling storms which occur every few Mars years and can significantly impact the atmosphere leading to increased dust aerosol sizes [6], an increase in middle atmosphere water vapour [7], and the formation of unseasonal water-ice clouds [8]. While the decrease in visibility during the global dust storm itself made cloud observation difficult, comparing the scattering phase function prior to and following the global dust storm can help to understand the long-term impacts of global dust storms on water-ice clouds.2. METHODSThe PFSS consists of 9 cloud movies of three frames each, taken using MSL’s navigation cameras, at a variety of pointings in order to observe a large range of scattering angles. The goal of the PFSS is to characterise the scattering properties of water-ice clouds and to determine ice crystal geometry. In each movie, clouds are identified using mean frame subtraction, and the phase function is computed using the formula derived by Cooper et al [3]. An average phase function can then be computed for the entirety of the ACB season.Figure 1 shows the temporal distributions of PFSS observations taken during MYs 34 and 35. We aim to capture both morning and afternoon observations in order to study any diurnal variability in water-ice clouds.3. RESULTS AND DISCUSSIONThere were a total of 26 PFSS observations taken in MY 35 between Ls~50°-160°, evenly distributed between AM and PM observations. Typically, times further from local noon (i.e. earlier in the morning or later in the afternoon) show stronger cloud features, and run less risk of being obscured by the presence of the sun. In all movies in which clouds are detected, a phase function can be calculated, and an average phase function determined for the whole ACB season. Future work will look at the water-ice cloud scattering properties for the MY 36 ACB season, allowing us to get more information about the interannual variability of the ACB and to further constrain the ice crystal habit. The PFSS observations will not only assist in our understanding of the long-term atmospheric impacts of global dust storms but also add to a more complete image of time-varying water-ice cloud properties.

Introduction: On Mars, near-surface and ground temperatures undergo massive diurnal fluctuations. Amplitudes can surpass 70 K between the daily maximum and minimum temperatures [1]. Because Mars’ thin atmosphere is largely transparent to infrared radiation, the solar radiation from the sun and the outgoing longwave radiation from the surface are the primary drivers of the near-surface temperature [2]. However, the influence from the atmosphere is not entirely negligible. It is well known that dust in the atmosphere has a secondary, but measurable, effect on the temperature by scattering visible-band solar radiation and absorbing longwave radiation [3]. This atmospheric thermal effect is not only caused by dust; Water-ice clouds have a similar influence, where outgoing longwave radiation may be absorbed and reflected back toward the ground, resulting in a warming of the near-surface temperature [4]. This project will investigate the amount of flux reflected by water-ice clouds by calculating the thermal forcing at the Phoenix landing site. Background: The Phoenix mission landed in the Martian northern Arctic, at a latitude of 68.2°N in 2008. Phoenix operated for 151 sols, collecting data up to and through the northern summer solstice. About 60 sols into the mission, water-ice clouds were observed both by images taken by the Stereo Surface Imager (SSI) [5] and by backscatter detected using a light detecting and ranging (LIDAR) instrument onboard the lander [6]. On four occasions, by using the LIDAR and SSI together, surface-fog was detected [7]. In the second half of the mission, surface-based clouds formed nightly around 23:00 Local True Solar Time (LTST). By 01:00 LTST, a second clouds base formed at altitudes near 4 km. The clouds dissipated by the late morning, but were observed to linger as the mission progressed past summer solstice [8]. Methods: Data for the near-surface air temperature are acquired from the Planetary Data System. Phoenix carried three thin-wire temperature sensors at heights of 1 m, 0.5 m, and 0.25 m off the deck of the lander, itself located 1 m above the surface. Temperature measurements were recorded every 2 s through the duration of a sol, with an approximately 20-minute break, usually occurring around midday. To determine the thermal impacts due to water-ice clouds, an energy balance at the surface is needed. Adapted from [9], the energy balance is given by where G is the net flux into the ground, S is the solar radiation, α is the surface albedo, LW↓ is the longwave radiation downwelling from the atmosphere, LW↑ is the longwave radiation emitted from the surfaced, H is the sensible heat flux, and L is the latent heat flux of water. R describes the additional longwave radiation downwelling from the atmosphere, which we attribute to water-ice clouds. R is maintained as an independent parameter which may be varied throughout a run of the model in 3 hour-intervals. With this energy balance, a subsurface conduction model is used to find the surface temperature at the Phoenix site. At each timestep, the surface temperature is coupled to the air temperature by where the terms are described in [9]. The modelled air temperatures are plotted against the air temperature data collected by Phoenix to evaluate the additional flux reflected by clouds (given by R) that is needed for the model to match the data collected in situ. Results and Discussion: Figure 1(a) shows the modelled temperaure plotted against the Phoenix data for sol 3 of the mission. During the midday, R = 0 W m-2 implying there is no flux reflected from water-ice clouds. Moving into the evening, R = 5 W m-2 starting at 21:00 LTST. This increases to 8 W m-2 by 00:00 LTST. At 03:00 LTST, the reflected flux drops back down to 5 W m-2, and is back to 0 W m-2 by 06:00 LTST. This additional flux is not a dominant energy term, as shown in Figure 1(b), but a resulting temperature increase of 2 K is seen. This analysis suggests that clouds were present at the Phoenix landing site earlier than they were detected in images or LIDAR data products. Moving forward, the amount of flux reflected by water-ice clouds will be determined for each sol of the misson. This will show how the reflected flux evolves diurnally – particularly through the nighttime – and as the mission progressed past summer solstice. References: [1] Martínez G.M. et al (2017) Space Sci Rev, 212, 295–338. [2] Savijärvi H. (2014) Icarus, 242, 105–111. [3] Guzewich S.D. et al (2019) Geophys. Res. Lett., 46, 71–79. [4] Wilson R.J. (2007) Geophys. Res. Lett., 34. [5] Moores J.E. et al (2010) JGR: Planets, 115. [6] Whiteway J.A. et al (2009) Science, 325, 68–70. [7] Moores J.E. et al (2011) Geophys. Res. Lett., 38. [8] Dickinson C. et al (2010) Geophys. Res. Lett., 37. [9] Martínez G.M. et al (2014) JGR: Planets, 119, 1822–1838.

The Gemini Observatory, a program of NSF’s NOIRLab, provides the astronomical communities in five participant countries with state-of-the-art astronomical facilities that allocate observing time in proportion to each country's contribution. In this paper we present an overview of the Gemini International Time Allocation Committee (ITAC) process whose purpose is to merge the successful proposals to create a single combined list of programs for execution on the two Gemini telescopes. The process of merging the successful programs from the National Time Allocation Committee (NTAC) is a complex process with many variables and considerations. This paper describes in detail the how-to (at the time of writing) of the main goals of the process, which are fairness and efficiency; ensuring that the telescopes are being used efficiently, and are never sitting idle when they could be executing a program of interest for one of the participants, as well as the users from the communities are not wasting time writing filler proposals that will never get executed. The success of this process is measured in executing the maximum number of highly ranked scientific programs within these constraints.

The Global Dust Storm of Mars Year 34 was observed by the Mars Science Laboratory (MSL) in Gale crater, and many atmospheric effects were seen during its duration. Using atmospheric observations taken by MSL, water-ice cloud opacity and scattering phase function are calculated, allowing comparison of these quantities before and after the dust storm. The average phase function was calculated for the Mars Year 34 Aphelion Cloud Belt (ACB) season, before the global dust storm, and will be calculated for the ACB season following. Opacity calculations are computed throughout the Martian year. The results of these calculations will indicate any impacts the global dust storm may have on Martian water-ice clouds. 1. INTRODUCTION The Martian atmosphere has long been the subject of study, both in situ and remotely, and as a result we are able to observe its dynamic nature. Water-ice clouds are one such dynamic feature, and their similarities to Earth-based clouds provide an opportunity to learn more not just about Martian weather but our own climate processes. The Mars Science Laboratory (MSL) in Gale Crater has been observing cloud activity in the region for the entirety of its mission to date. Cloud movies captured by MSL can be analysed in order to determine optical parameters such as opacity[1] and scattering phase function[2]. The most important time of year for cloud activity around Gale Crater is the Aphelion Cloud Belt season, which tends to peak between solar longitudes (Ls) 60-100° and is characterised by an increase in equatorial cloud formation[3]. MSL has been in Gale Crater for nearly four Martian Years, and as a result has been able to observe the time-varying nature of the Martian climate on daily, seasonal, and annual scales. The presence of a global dust storm in 2018 (Mars Year 34) gave further opportunity to study not only the event itself, but its lasting effect on the Martian atmosphere. 2. BACKGROUND 2.1 The Mars Year 34 Global Dust Storm The global dust storm of Mars Year (MY) 34 was a planet encircling dust storm which lasted from about Ls~188° to Ls~250°[4]. Global dust storms typically occur every 3-4 years[5] and significantly impact the atmosphere, causing temperature and pressure fluctuations[4] and an increase in water vapour in the middle atmosphere[6]. While the decrease in visibility made it difficult to observe clouds during the global dust storm, a before-and-after comparison of cloud opacity and scattering phase function provide understanding about longstanding atmospheric effects of global dust storms. 2.2 MSL Atmospheric Movies The navigation cameras onboard MSL take two types of movies year-round, Zenith Movies (ZM) and Suprahorizon Movies (SHM), and a third observation during the ACB season, the Phase Function Sky Survey (PFSS). ZM and SHM are both 8 frame movies taken over 6 minutes, with ZMs pointing to the Zenith and SHMs pointing just above the crater rim. The PFSS is a mosaic of 9 3-frame movies at a variety of pointings making a dome surrounding the rover. In order to better identify clouds, all three types of movies undergo mean frame subtraction, a process by which an average frame is subtracted from each frame of the movie, leaving only the time variable component. This can be seen in Figure 1. 3. METHODS ZM and SHM can be analysed to determine cloud optical thickness, which has been computed for the first two Martian Years of MSL’s mission (Ls=160° of MY 31 to Ls=160° of MY 33)[7]. After mean frame subtraction, a radiance map (Figure 2) is made of a single frame of the movie, which is examined manually for a region containing cloud and empty sky, giving a variation in spectral radiance (Iλ,VAR) which is then used to compute the optical thickness. During the ACB season, the high-cloud formula, derived by Kloos et al, is used to estimate opacity, which assumes clouds are high, optically thin, and composed of water-ice crystals[1]. The PFSS was first instituted in MY 34, and an average scattering phase function determined for that year[2]. As with optical thickness, Iλ,VAR is determined from a radiance map for each movie and used to compute the phase function, using the formula derived by Cooper et al[2]. With the MY 35 ACB season ending in February of 2020, there is now another complete set of 26 PFSS observations, giving 234 total movies. 4. RESULTS AND DISCUSSION Currently ZM and SHM have been processed and have radiance maps from sol 1706 to sol 2748, a total of 466 movies. All of these must be checked manually for quality, and to identify high and low radiance points. This process is ongoing. Following the calculation of optical thickness for all cloud movies, the catalogue of MSL cloud opacities will be extended from two Martian years to four. In addition, the 234 PFSS movies must likewise be checked, a process that is nearing completion at time of writing. By the time of the conference, it is anticipated that an average phase function for MY 35 will be calculated, allowing comparison with that of MY 34. Due to the larger size of the opacity dataset, opacity calculations are anticipated to take more time. These observations will allow us to better understand not only the lasting atmospheric effects of global dust storms, but also will extend our understanding of variability in water-ice cloud optical properties over larger timescales. REFERENCES [1] Kloos, J.L, et al, Adv. Space Res., 2016. [2] Cooper, B.A., et al, P&SS, 2019. [3] Wolff, M.J., et al, JGR, 1999. [4] Guzewich, S.D. et al, Geophys. Res. Lett., 2019. [5] Zurek, R.W., and Martin, L.J., JGR, 1993. [6] Aoki, S.A., et al, JGR-Planets, 2019. [7] Kloos, J.L. et al, JGR-Planets, 2018.

This paper constrains the scattering phase function of water ice clouds (WICs) found within Mars' Aphelion Cloud Belt (ACB), determined from orbit by processing publicly available raw Mars Color Imager (MARCI) data spanning solar longitudes (Ls) 42-170 during Mars Years (MYs) 28 and 29. MARCI visible wavelength data were calibrated and then pipeline-processed to select the pixels most likely to possess clouds. Mean phase function curves for the MARCI blue filter data were derived, and for all seasons investigated, modeled aggregates, plates, solid and hollow columns, bullet rosettes, and droxtals were all found to be plausible habits. Spheres were found to be the least plausible, but still possible. Additionally, this work probed the opposition surge to examine the slope of the linear relationship between column ice water content and cloud opacity on Mars, and found a significant dependence on particle radius. The half-width-half-maxima (HWHM) of the visible 180 degree peak of five MARCI images were found to agree better with modeled HWHM for WICs than with modeled HWHM for dust., Comment: 45 pages, 12 figures, preprint for the Journal of Planetary and Space Science

This study retrieved estimated altitudes of Martian water-ice clouds through a comparison of observations taken by the Mars Science Laboratory (MSL, Curiosity) rover and the Mars Regional Atmospheric Modelling System (MRAMS). The vertical pointing of a Zenith Movie (ZM) allows many wind velocities and directions to be measured when clouds are observed, however without a lidar onboard the altitude of these clouds cannot be directly determined. By simulating conditions at Gale Crater with MRAMS, wind properties found in ZMs can be correlated with model outputs to estimate cloud altitudes at Gale Crater from the surface for the first time. These results are evaluated to assess any diurnal and seasonal cloud altitude patterns above Gale crater.

This chapter offers a brief history of debate within Black communities in the period between Emancipation and the Civil Rights Movement, with a particular focus on debate activities from the 1920s through the 1960s. Community debate programs and the emergence of collegiate debate in this period fit on the one hand with the importance of debate in the creation and cementation of a Black public sphere, but it also sets the stage for the cultures of debate that emerge during the Civil Rights Movement. Murray suggests that access to a debate team and other modern forms of extracurricular activity increased the rigor of her educational experience and chipped away at the sense of inferiority that a separate and unequal system of public education had produced in Black children, an argument that would be critical to the overturning of the Plessy decision in 1954.

One hundred fifty years after Harriet Tubman helped free 750 slaves during the Raid at Combahee Ferry, becoming the first woman in US history to successfully lead a military campaign, hip-hop mogul Russell Simmons chose to commemorate her legacy by releasing a highly offensive web video titled “Harriet Tubman Sex Tape.” In it, Harriet Tubman’s character, played by YouTube comedienne Shanna Malcolm, can be seen willingly cajoling the master into sex, and even penetrating him with an unseen strap-on, in order to manipulate him into giving her her freedom. Meanwhile, one of Harriet’s minions, played by DeStorm Power, hides in a closet with a video camera. The video was released by Simmons’s new YouTube network, All Def Digital. At best, Simmons is utterly clueless about the realities of black female victimization during slavery; at worst, he’s a willfully ignorant misogynist who delights in minimizing the pain of slavery and rape of black women. This is one of the problems with the resurgence of black nationalist politics that inevitably follows the unjust killing of black boys like Trayvon Martin. With a scarily consistent frequency, black women’s political histories and needs are not only minimized but utterly discounted in service of a narrative of black male racial victimhood.

Titan, with its thick, nitrogen-dominated atmosphere, has been seen from satellite and terrestrial observations to harbour methane clouds. To investigate whether atmospheric features such as clouds could also be visible from the surface of Titan, data taken with the Side Looking Imager (SLI) on-board the Huygens probe after landing have been analysed to identify any potential atmospheric features. In total, 82 SLI images were calibrated, processed and examined for features. The calibrated images show a smooth vertical radiance gradient across the images, with no other discernible features. After mean-frame subtraction, six images contained an extended, horizontal feature that had a radiance value that lay outside the 95% confidence limit of the predicted radiance when compared to regions higher and lower in the images. The change in optical depth of these features were found to be between 0.005 and 0.014. It is considered that these features most likely originate from the presence of a fog bank close to the horizon that rises and falls during the period of observation., Comment: Icarus, Available online 9 February 2016, ISSN 0019-1035

Coined by Kimberlé Crenshaw in 1989, the term intersectionality has become the key analytic framework through which feminist scholars in various fields talk about the structural identities of race, class, gender, and sexuality. This chapter situates intersectionality within a long history of black feminist theorizing about interlocking systems of power and oppression, arguing that intersectionality is not an account of personal identity but one of power. It challenges feminist theorists, including Robyn Wiegman, Jennifer Nash, and Jasbir Puar, who have attempted to move past intersectionality because of its limitations in fully attending to the contours of identity. The chapter also maps conversations within the social sciences about intersectionality as a research methodology. Finally, it considers what it means for black women to retain paradigmatic status within intersectionality studies, whether doing so is essentialist, and therefore problematic, or whether attempts to move “beyond” black women constitute attempts at erasure and displacement.

I was a graduate student in Atlanta when Tyler Perry made the leap from stage plays to movies. I was only mildly familiar with, and generally not a fan of, the Madea plays, which struck me as being a throwback to the era of the Chitlin’ Circuit. Even so, I eagerly supported his first film Diary of a Mad Black Woman (2005), and enjoyed it. Perry seemed sympathetic to black women’s struggles in heterosexual relationships, the ways that men “did us wrong,” our legitimate desire for revenge, and the importance of our faith. Madea’s acerbic wit, combative posturing, and fiercely protective devotion to her family were a welcome and familiar narrative, invoking thoughts of the women in my life who absolutely “don’t take no mess.” Thus, I eagerly went to see every film, most on opening weekends. Even though I was a self-identified feminist, I drowned out the protestations of my feminist friends, dismissing them as too academic for their own good. The women in Perry’s films reminded me of women I knew. And, as an evangelical Christian and regular church attendee, I found the sermons and faith themes in his movies poignant and instructive. In short, I encountered Tyler Perry at a critical juncture in my own evolution as an academic, a black feminist scholar and critic, and an increasingly theologically liberal Christian from an evangelical background.