Space Logistics Modeling and Simulation Analysis using SpaceNet: Four Application Cases

The future of space exploration will not be limited to sortie-style missions to single destinations. Even in present exploration taking place at the International Space Station in low-Earth orbit, logistics is complicated by flights arriving from five launch sites on Earth. The future challenges of space logistics given complex campaigns of interconnected missions in deep space will require innovative tools to aid planning and conceptual design. This paper presents a modeling framework to evaluate the propulsive and logistics feasibility of space exploration from the macro-logistics perspective, which covers the delivery of elements and resources to support demands generated during exploration. The modeling framework is implemented in a versatile and unifying software tool, SpaceNet, for general space exploration scenario analysis. Four space exploration scenarios are presented as application cases to highlight the applicability of the framework across vastly different scenarios. The first case investigates the resupply of the International Space Station between 2010 and 2015 using 77 missions combining NASA, European Space Agency, Japanese Space Agency, Russian Space Agency, and commercial space transportation. The second case models a lunar outpost build-up consisting of 17 flights to achieve continuous human presence over eight years. The third case models and evaluates a conceptual sortie-style mission to a near-Earth object, 1999 AO10. Finally, the fourth case models a flexible path type human exploration in the vicinity of Mars using a combination of human and tele-operated exploration. Taken together these cases demonstrate the challenges and logistical requirements of future human space exploration campaigns during the period from 2010-2050 and illustrate the ability of SpaceNet to model and simulate the feasibility of meeting these requirements.United States. Dept. of DefenseUnited States. Air Force Office of Scientific ResearchAmerican Society for Engineering Education. National Defense Science and Engineering Graduate Fellowship32 CFR 168

Learning from failure

We study decentralized learning in organizations. Decentralization is captured through a symmetry constraint on agents’ strategies. Among such attainable strategies, we solve for optimal and equilibrium strategies. We model the organization as a repeated game with imperfectly observable actions. A fixed but unknown subset of action profiles are successes and all other action profiles are failures. The game is played until either there is a success or the time horizon is reached. For any time horizon, including infinity, we demonstrate existence of optimal attainable strategies and show that they are Nash equilibria. For some time horizons, we can solve explicitly for the optimal attainable strategies and show uniqueness. The solution connects the learning behavior of agents to the fundamentals that characterize the organization: Agents in the organization respond more slowly to failure as the future becomes more important, the size of the organization increases and the probability of success decreases.Game theory

Randomized Trial of Partial Gland Ablation with Vascular Targeted Phototherapy versus Active Surveillance for Low Risk Prostate Cancer: Extended Followup and Analyses of Effectiveness

PURPOSE: The prospective PCM301 trial randomized 413 men with low risk prostate cancer to partial gland ablation with vascular targeted photodynamic therapy in 207 and active surveillance in 206. Two-year outcomes were reported previously. We report 4-year rates of intervention with radical therapy and further assess efficacy with biopsy results. MATERIALS AND METHODS: Prostate biopsies were mandated at 12 and 24 months. Thereafter patients were monitored for radical therapy with periodic biopsies performed according to the standard of care at each institution. Ablation efficacy was assessed by biopsy results overall and in field in the treated lobe or the lobe with index cancer. RESULTS: Conversion to radical therapy was less likely in the ablation cohort than in the surveillance cohort, including 7% vs 32% at 2 years, 15% vs 44% at 3 years and 24% vs 53% at 4 years (HR 0.31, 95% CI 0.21-0.46). Radical therapy triggers were similar in the 2 arms. Cancer progression rates overall and by grade were significantly lower in the ablation cohort (HR 0.42, 95% CI 0.29-0.59). End of study biopsy results were negative throughout the prostate in 50% of patients after ablation vs 14% after surveillance (risk difference 36%, 95% CI 28-44). Gleason 7 or higher cancer was less likely for ablation than for surveillance (16% vs 41%). Of the in field biopsies 10% contained Gleason 7 cancer after ablation vs 34% after surveillance. CONCLUSIONS: In this randomized trial of partial ablation of low risk prostate cancer photodynamic therapy significantly reduced the subsequent finding of higher grade cancer on biopsy. Consequently fewer cases were converted to radical therapy, a clinically meaningful benefit that lowered treatment related morbidity

Nurturing lifelong learning in communities through the National University of Lesotho: prospects and challenges

This paper analyses one aspect of a pan-African action research project called ITMUA (Implementing the Third Mission of Universities in Africa). This particular paper draws on the data from that project to explore the National University of Lesotho’s contribution to lifelong learning in its communities. It provides background information on the ITMUA initiative and analyses interview and focus group responses to two case studies in terms of their contribution to lifelong learning. It uses, as its analytical framework, a modified version of Mbigi’s African perspective on the four De Lors’ ‘pillars’, by adding a fifth pillar, courtesy of Torres. The paper argues that community engagement is a two-way process between universities and their wider constituencies with opportunities for mutual lifelong learning. But there are also challenges of understanding and process which must be addressed if the full range of these lifelong learning pillars is to be accommodated within African contexts. The paper provides an introduction to the history of community engagement in Africa as a university mission, followed by a brief discussion of lifelong learning within African perspectives. After describing the particular context of Lesotho, the concept of community service and community engagement in contemporary African contexts introduces the action research project and the case studies. The final part of the paper presents and discusses the research findings

The future for follow-up of gynaecological cancer in Europe. Summary of available data and overview of ongoing trials

After completing treatment, most patients follow a pre-determined schedule of regular hospital outpatient appointments, which includes clinical examinations, consultations and routine tests. After several years of surveillance, patients are transferred back to primary care. However, there is limited evidence to support the effectiveness and efficiency of this approach. This paper examines the current rationale and evidence base for hospital-based follow-up after treatment for gynaecological cancer. We investigate what alternative models of care have been formally evaluated and what research is currently in progress in Europe, in order to make tentative recommendations for a model of follow-up. The evidence base for traditional hospital based follow-up is limited. Alternative models have been reported for other cancer types but there are few evaluations of alternative approaches for gynaecological cancers. We identified five ongoing European studies; four were focused on endometrial cancer patients and one feasibility study included all gynaecological cancers. Only one study had reached the reporting stage. Alternative models included nurse-led telephone follow-up and comparisons of more intensive versus less intensive regimes. Outcomes included survival, quality of life, psychological morbidity, patient satisfaction and cost effectiveness of service. More work is needed on alternative strategies for all gynaecological cancer types. New models will be likely to include risk stratification with early discharge from secondary care for early stage disease with fast track access to specialist services for suspected cancer recurrence or other problems

Energetic particle influence on the Earth's atmosphere

This manuscript gives an up-to-date and comprehensive overview of the effects of energetic particle precipitation (EPP) onto the whole atmosphere, from the lower thermosphere/mesosphere through the stratosphere and troposphere, to the surface. The paper summarizes the different sources and energies of particles, principally galactic cosmic rays (GCRs), solar energetic particles (SEPs) and energetic electron precipitation (EEP). All the proposed mechanisms by which EPP can affect the atmosphere are discussed, including chemical changes in the upper atmosphere and lower thermosphere, chemistry-dynamics feedbacks, the global electric circuit and cloud formation. The role of energetic particles in Earth’s atmosphere is a multi-disciplinary problem that requires expertise from a range of scientific backgrounds. To assist with this synergy, summary tables are provided, which are intended to evaluate the level of current knowledge of the effects of energetic particles on processes in the entire atmosphere

Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020

We show the distribution of SARS-CoV-2 genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three available genomic nomenclature systems for SARS-CoV-2 to all sequence data from the WHO European Region available during the COVID-19 pandemic until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation. We provide a comparison of the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2.Peer reviewe

Use of >100,000 NHLBI Trans-Omics for Precision Medicine (TOPMed) Consortium whole genome sequences improves imputation quality and detection of rare variant associations in admixed African and Hispanic/Latino populations

Most genome-wide association and fine-mapping studies to date have been conducted in individuals of European descent, and genetic studies of populations of Hispanic/Latino and African ancestry are limited. In addition, these populations have more complex linkage disequilibrium structure. In order to better define the genetic architecture of these understudied populations, we leveraged >100,000 phased sequences available from deep-coverage whole genome sequencing through the multi-ethnic NHLBI Trans-Omics for Precision Medicine (TOPMed) program to impute genotypes into admixed African and Hispanic/Latino samples with genome-wide genotyping array data. We demonstrated that using TOPMed sequencing data as the imputation reference panel improves genotype imputation quality in these populations, which subsequently enhanced gene-mapping power for complex traits. For rare variants with minor allele frequency (MAF) 86%. Subsequent association analyses of TOPMed reference panel-imputed genotype data with hematological traits (hemoglobin (HGB), hematocrit (HCT), and white blood cell count (WBC)) in ~21,600 African-ancestry and ~21,700 Hispanic/Latino individuals identified associations with two rare variants in the HBB gene (rs33930165 with higher WBC [p = 8.8x10-15] in African populations, rs11549407 with lower HGB [p = 1.5x10-12] and HCT [p = 8.8x10-10] in Hispanics/Latinos). By comparison, neither variant would have been genome-wide significant if either 1000 Genomes Project Phase 3 or Haplotype Reference Consortium reference panels had been used for imputation. Our findings highlight the utility of the TOPMed imputation reference panel for identification of novel rare variant associations not previously detected in similarly sized genome-wide studies of under-represented African and Hispanic/Latino populations