Rapid Design of Gravity Assist Trajectories

Several International Solar Terrestrial Physics (ISTP) missions require the design of complex gravity assisted trajectories in order to investigate the interaction of the solar wind with the Earth's magnetic field. These trajectories present a formidable trajectory design and optimization problem. The philosophy and methodology that enable an analyst to design and analyse such trajectories are discussed. The so called 'floating end point' targeting, which allows the inherently nonlinear multiple body problem to be solved with simple linear techniques, is described. The combination of floating end point targeting with analytic approximations with a Newton method targeter to achieve trajectory design goals quickly, even for the very sensitive double lunar swingby trajectories used by the ISTP missions, is demonstrated. A multiconic orbit integration scheme allows fast and accurate orbit propagation. A prototype software tool, Swingby, built for trajectory design and launch window analysis, is described

Minority Stress and Leukocyte Gene Expression In Sexual Minority Men Living With Treated HIV Infection

Sexual minority (i.e., non-heterosexual) individuals experience poorer mental and physical health, accounted for in part by the additional burden of sexual minority stress occurring from being situated in a culture favoring heteronormativity. Informed by previous research, the purpose of this study was to identify the relationship between sexual minority stress and leukocyte gene expression related to inflammation, cancer, immune function, and cardiovascular function. Sexual minority men living with HIV who were on anti-retroviral medication, had viral load \u3c 200 copies/mL, and had biologically confirmed, recent methamphetamine use completed minority stress measures and submitted blood samples for RNA sequencing on leukocytes. Differential gene expression and pathway analyses were conducted comparing those with clinically elevated minority stress (n = 18) and those who did not meet the clinical cutoff (n = 20), covarying reactive urine toxicology results for very recent stimulant use. In total, 90 differentially expressed genes and 138 gene set pathways evidencing 2-directional perturbation were observed at false discovery rate (FDR) \u3c 0.10. Of these, 41 of the differentially expressed genes and 35 of the 2-directionally perturbed pathways were identified as functionally related to hypothesized mechanisms of inflammation, cancer, immune function, and cardiovascular function. The neuroactive-ligand receptor pathway (implicated in cancer development) was identified using signaling pathway impact analysis. Our results suggest several potential biological pathways for future work investigating the relationship between sexual minority stress and health

China's influence in Australia and New Zealand: Making the democratic world safe for dictatorship

Australia and New Zealand both established diplomatic relations with the People’s Republic of China in December of 1972. The assumed tensions between economic openness and political closure have instead been felt primarily in democratic countries developing close trade relations with China. A Chinese-language newspaper engaged in open and critical reporting on contemporary Chinese matters found its private business advertisers placed under unprecedented state pressures. China’s most determined and successful infiltration efforts have been focused on exerting control over the Chinese diaspora by bringing Chinese language media, Chinese community organizations, Chinese community leaders and local politicians of Chinese heritage into its sphere of influence. In New Zealand, Chinese-language media are also being rapidly incorporated into China’s system of media control. The most alarming cases of China’s influence take place in elite politics, ranging from political donations and manipulation of elections to co-option of political leaders and cultivation of politicians

Humidification Factors from Laboratory Studies of Fresh Smoke from Biomass Fuels

Measurements of smoke aerosol humidification factors were performed in a laboratory for different biomass fuel types and burn conditions. Two nephelometers simultaneously measured dry and humidified light scattering coefficients (bsp(dry) and bsp(RH), respectively), providing the first observations of the temporal evolution of the humidification factor (f(RH) = bsp(RH)/bsp(dry)) for fresh (minutes-old) smoke. Hygroscopic characteristics of the smoke aerosols varied with fuel type and fire conditions, with the mean f(RH) ranging from 1.01 to 1.95 for fresh minutes-old smoke for the relative humidity (RH) range of 70-94%. These f(RH) values exhibited temporal variability, with some fuels alternating from hygroscopic to nonhygroscopic within minutes. Humidograms were also obtained, demonstrating that smoke from different fuels begins to take up water at different RH values. Humidification factors for hour-old smoke ranged from 1.10 to 1.51 for RH \u3e 90%. Finally, light-absorbing carbon mass measured with a multiwavelength aethalometer demonstrated different spectral responses as a function of fuel type. These laboratory experiments demonstrate the complexity of smoke hygroscopicity from young fires and are essential for understanding the radiative effects of biomass burning in the ambient atmosphere

Parkinson’s Disease Support Groups in Rural America: Barriers, Resources, and Opportunities

People with Parkinson’s disease who live in rural communities may lack information and support regarding their condition, compared to those in urban or suburban areas. For the study described herein, the researchers sought to gain a deeper understanding of support group experiences of rural Parkinson’s disease stakeholders through merging an interpretive phenomenological design with Community-based Participatory Research (CBPR). Using this merged approach, we collected qualitative data from five focus groups to gain a community perspective. The qualitative data was analyzed thematically, first, and then further explored for an overall essence. The theme, Support Group Benefits: Opportunities for Communication expounded upon the importance of support groups to Parkinson’s disease stakeholders. Barriers to Support Group Participation represented how the disease and the rural living conditions inhibited support group participation. Strategies to Improve Support Group Access demonstrated the different ways that the stakeholders had tried to overcome barriers and strengthen support groups. Notably, some participants discussed ways that support groups could increase their accessibility to more individuals with Parkinson’s living rurally so that they endured as a future resource. The themes and accessibility recommendations that emerged led the researchers to interpret the overall essence of this work as, experiencing support group benefits despite barriers, leaving a legacy

Building Community Capacity for Integrating Engineering in Rural Middle School Science Classrooms

: Broadening participation in engineering is an important national priority and has led to increasing demands for engineering content to be integrated into traditional K-12 curriculum. However, expecting teachers to incorporate engineering into their classrooms without additional training or resources is unreasonable. Partnering teachers with industry partners is one promising way to prioritize integrated science and engineering content while also introducing youth to possible career paths. In this programmatic article, we introduce the Partnering with Educators and Engineers in Rural Schools (PEERS) project that focuses on the collaborative design, implementation, and study of recurrent hands-on engineering activities with middle school youth in three rural communities in or near Appalachia. We discuss the curricular priorities of the program as well as preliminary findings on both student-focused and capacity-building metrics across the partnerships. Key discussion points include (1) a need to distill goals for engineering outreach by wrestling with what success might really look like for middle-school youth engagement with engineering and (2) cultivating community capacity to better support education systems and the simultaneous potential for and challenges of collaborating to build such infrastructure

Water activity and activation diameters from hygroscopicity data - Part I: Theory and application to inorganic salts

International audienceA method is described that uses particle hygroscopicity measurements, made with a humidified tandem differential mobility analyzer (HTDMA), to determine solution water activity as a function of composition. The use of derived water activity data in computations determining the ability of aerosols to serve as cloud condensation nuclei (CCN) is explored. Results for sodium chloride and ammonium sulfate are shown in Part I. The methodology yields solution water activities and critical dry diameters for ammonium sulfate and sodium chloride in good agreement with previously published data. The approach avoids the assumptions required for application of simplified and modified Köhler equations to predict CCN activity, most importantly, knowledge of the molecular weight and the degree of dissociation of the soluble species. Predictions of the dependence of water activity on the mass fraction of aerosol species are sensitive to the assumed dry density, but predicted critical dry diameters are not

Student Outcomes from the Collective Design and Delivery of Culturally Relevant Engineering Outreach Curricula in Rural and Appalachian Middle Schools

Middle school is a pivotal time for career choice, and research is rich with studies on how students perceive engineering, as well as corresponding intervention strategies to introduce younger students to engineering and inform their conceptions of engineering. Unfortunately, such interventions are typically not designed in culturally relevant ways. Consequently, there continues to be a lack of students entering engineering and a low level of diverse candidates for this profession. The purpose of this study was to explore how students in rural and Appalachian Virginia conceive of engineering before and after engagement with culturally relevant hands-on activities in the classroom. We used student responses to the Draw an Engineer Test (DAET), consisting of a drawing and several open-ended prompts administered before and after the set of engagements, to answer our research questions related to changes in students’ conceptions of engineering. We used this study to develop recommendations for teachers for the use of such engineering engagement practices and how to best assess their outcomes, including looking at the practicality of the DAET. Overall, we found evidence that our classroom engagements positively influenced students’ conceptions of engineering in these settings

Water activity and activation diameters from hygroscopicity data - Part II: Application to organic species

International audienceA method has been developed for using particle hygroscopicity measurements made with a humidified tandem differential mobility analyzer (HTDMA) to determine water activity as a function of solute weight percent. In Part I, the method was tested for particles composed of sodium chloride and ammonium sulfate. Here, we report results for several atmospherically-relevant organic species: glutaric acid, malonic acid, oxalic acid and levoglucosan. Predicted water activities for aqueous dicarboxylic acid solutions are quite similar in some cases to published estimates and the simplified predictions of Köhler theory, while in other cases substantial differences are found, which we attribute primarily to the semivolatile nature of these compounds that makes them difficult to study with the HTDMA. In contrast, estimates of water activity for levoglucosan solutions compare very well with recently-reported measurements and with published data for aqueous glucose and fructose solutions. For all studied species, the critical dry diameters active at supersaturations between 0.2 and 1% that are computed with the HTDMA-derived water activities are generally within the experimental error (~20%) estimated in previously-published direct measurements using cloud condensation nuclei counters. For individual compounds, the variations in reported solution water activity lead to uncertainties in critical dry diameters of 5-25%, not significantly larger than the uncertainty in the direct measurements. To explore the impact of these uncertainties on modeled aerosol-cloud interactions, we incorporate the variations in estimates of solution water activities into the description of hygroscopic growth of aerosol particles in an adiabatic parcel model and examine the impact on the predicted drop number concentrations. For the limited set of initial conditions examined here, we find that the uncertainties in critical dry diameters for individual species lead to 0-21% changes in drop number concentration, with the largest effects at high aerosol number concentrations and slow updraft velocities. Ammonium sulfate, malonic acid and glutaric acid have similar activation behavior, while glutaric acid and levoglucosan are somewhat less hygroscopic and lead to lower drop number concentrations; sodium chloride is the most easily activated compound. We explain these behaviors in terms of a parameter that represents compound hygroscopicity, and conclude that this parameter must vary by more than a factor of 2 to induce more than a 15% change in activated drop number concentrations. In agreement with earlier studies, our results suggest that the number concentration of activated drops is more sensitive to changes in the input aerosol size and number concentrations and the applied updraft velocity than to modest changes in the aerosol composition and hygroscopic properties