Constraints on Mars Aphelion Cloud Belt Phase Function and Ice Crystal Geometries

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 Scienc

Controlling pulse propagation in optical fibers through nonlinearity and dispersion management

In case of the nonlinear Schr\"odinger equation with designed group velocity dispersion, variable nonlinearity and gain/loss; we analytically demonstrate the phenomenon of chirp reversal crucial for pulse reproduction. Two different scenarios are exhibited, where the pulses experience identical dispersion profiles, but show entirely different propagation behavior. Exact expressions for dynamical quasi-solitons and soliton bound-states relevant for fiber communication are also exhibited.Comment: 4 pages, 5 eps figure

Celebrity advocacy and public engagement: the divergent uses of celebrity

This article sounds a cautionary note about the instrumental use of celebrity advocacy to (re)engage audiences in public life. It begins by setting out the steps necessary to achieve public recognition of a social problem requiring a response. It then presents empirical evidence which suggests that those most interested in celebrity, while also paying attention to the main stories of the day, are also least likely to participate in any form of politics. However, this does not rule out the possibility of forging a link between celebrity and public engagement, raising questions about what would potentially sustain such an articulation. After discussing the broader cultural context of celebrity advocacy in which perceived authenticity functions valorised form of symbolic capital, the article outlines a phenomenological approach to understanding the uses audiences make of celebrity advocacy, using the example of a Ewan McGregor UNICEF appeal for illustration. It concludes that while media encounters with celebrities can underpin a viewer’s sense of self, this is as likely to lead to the rationalisation of inaction as a positive response to a charity appeal

Evaluation of changes in sleep breathing patterns after primary palatoplasty in cleft children

Introduction: There is a need to more clearly understand the characteristics of breathing patterns in children with cleft palate in the first year of life, as there is little data available to guide current practice. Pierre Robin patients are known to have a higher incidence, however we hypothesised sleep breathing disturbance is not confined to this sub-group of cleft patient. Methods: We conducted a prospective observational study of sleep disordered breathing patterns in a cohort of infants with oro-nasal clefts (cleft palate with or without cleft lip) to describe the spectrum of sleep breathing patterns both pre and post palate repair. Sleep breathing studies were performed pre- and post-operatively in sequential infants referred to a regional cleft lip and palate unit. Results of sleep breathing studies were analysed according to American Academy of Sleep Medicine scoring guidelines and correlated with clinical history and details of peri-operative respiratory compromise. The degree of sleep disordered breathing was characterised using desaturation indices (number of desaturations from baseline SpO2 of >=4%, per hour). Results: Thirty-nine infants were included in this study, twenty-five female and fourteen male. Twelve had isolated Cleft Palate as part of an associated syndrome. Patients were categorised into Isolated Cleft Palate, Isolated Cleft Palate in the context of Pierre Robin Sequence, and those with Cleft Lip and Palate. All groups demonstrated some degree of sleep breathing abnormality. Not unsurprisingly the eight infants with Pierre Robin Sequence had a significantly higher desaturation index before surgical intervention (p=0.043), and were more likely to require a pre-operative airway intervention (p=0.009). Palate repair in this group did not alter the relative distribution of patients in each severity category of sleep disorder breathing. Surgical repair of the secondary palate in the remaining children was associated with some improvement but by no means complete resolution of their sleep disordered breathing patterns. Conclusions: We conclude that sleep breathing disturbance is not confined to Pierre Robin patients alone and all cleft palate patients should undergo pre-operative and post-operative sleep breathing analysis

Affordances-in-practice:an ethnographic critique of social media logic and context collapse

Drawing on data gathered during ethnographic fieldwork in Mardin, a medium-sized town in southeast Turkey, this article shows that social media users actively appropriate online platforms and change privacy settings in order to keep different social spheres and social groups apart. Keeping different online social contexts distinct from each other is taken for granted as a way of using social media in Mardin. By contrast, social media scholars have extensively discussed the effects of social media in terms of context collapse. The article highlights how context collapse is the result of patterns of usage within Anglo-American contexts and not the consequence of a platform's architecture or social media logic. It then suggests a theoretical refinement of affordances, and proposes the concept of affordances-in-practice

Breaking Down Grit: Persistency and Flexibility in the Career Plans of Military Medical Students.

INTRODUCTION: The field of medicine is experiencing a crisis as high levels of physician and trainee burnout threaten the pipeline of future physicians. Grit, or passion and perseverance for long-term goals, has been studied in high-performing and elite military units and found to be predictive of successful completion of training in adverse conditions. The Uniformed Services University of the Health Sciences (USU) graduates military medical leaders who make up a significant portion of the Military Health System physician workforce. Taken together, an improved understanding of the relationships between burnout, well-being, grit, and retention among USU graduates is critical to the success of the Military Health System. MATERIALS AND METHODS: The current study was approved by the Institutional Review Board at USU and explored these relations among 519 medical students across three graduating classes. These students participated in two surveys approximately one year apart from October 2018 until November 2019. Participants completed measures on grit, burnout, and likelihood of leaving the military. These data were then merged with demographic and academic data (e.g., Medical College Admission Test scores) from the USU Long Term Career Outcome Study. These variables were then analyzed simultaneously using structural equation modeling to examine the relationships among variables in a single model. RESULTS: Results reaffirmed the 2-factor model of grit as both passion and perseverance (or interest consistency). No significant relationships emerged between burnout and other study variables. Sustained and focused interest was predictive of less likelihood of staying in the military. CONCLUSION: This study offers important insights into the relationship among well-being factors, grit, and long-term career planning in the military. The limitations of using a single-item measure of burnout and measuring behavioral intentions in a short time frame during undergraduate medical education highlight the importance of future longitudinal studies that can examine actual behaviors across a career lifespan. However, this study offers some key insights into potential impacts on the retention of military physicians. The findings suggest that military physicians who are most likely to stay in the military tend to embrace a more fluid and flexible medical specialty path. This is critical in expectation setting for the military to train and retain military physicians across a wide range of critical wartime specialties