Small Spacecraft for Low-Cost Planetary Missions

Small low-cost spacecraft offer the opportunity to carry out a variety of planetary exploration missions at modest cost as part of a sustained program. This study identifies scientifically valuable missions of modest cost that can be carried out by modifications of a single spacecraft design. These missions lend themselves to a continuing program of essentially constant funding level. Such a program could involve several launches spread over a period of 10 to 15 years at roughly two-year intervals. The stability offered by relatively constant funding, frequent launches, and the return of data in a more nearly constant fashion than is typical of planetary science in the recent past would greatly enhance solar system exploration and sustain a level of interest between the less frequent large programs, which require a major national commitment. The ability to construct capable, reliable spacecraft for modest cost and adapt them to the various missions without a major redesign is critical. Today\u27s developing small spacecraft technology offers that promise. Several typical candidate spacecraft have been identified and used as a basis for this study. Concurrently, several worthwhile planetary science missions have been identified. With these inputs, a candidate program plan has been developed to meet the criteria of constant funding, reasonably spaced launches, and worthwhile science objectives

Cultural and Family Challenges to Managing Type 2 Diabetes in Immigrant Chinese Americans

OBJECTIVE— Although Asians demonstrate elevated levels of type 2 diabetes, little attention has been directed to their unique cultural beliefs and practices regarding diabetes. We describe cultural and family challenges to illness management in foreign-born Chinese American patients with type 2 diabetes and their spouses. RESEARCH DESIGN AND METHODS— This was an interpretive comparative interview study with 20 foreign-born Chinese American couples (n = 40) living with type 2 diabetes. Multiple (six to seven) semistructured interviews with each couple in individual, group, and couple settings elicited beliefs about diabetes and narratives of care within the family and community. Interpretive narrative and thematic analysis were completed. A separate respondent group of 19 patients and spouses who met the RESULTS— Cultural and family challenges to diabetes management within foreign-born Chinese American families included how 1) diabetes symptoms challenged family harmony, 2) dietary prescriptions challenged food beliefs and practices, and 3) disease management requirements challenged established family role responsibilities. CONCLUSIONS— Culturally nuanced care with immigrant Chinese Americans requires attentiveness to the social context of disease management. Patients’ and families’ disease management decisions are seldom made independent of their concerns for family well-being, family face, and the reciprocal responsibilities required by varied family roles. Framing disease recommendations to include cultural concerns for balance and significant food rituals are warranted

Estimating Associations Between Annual Concentrations of Particulate Matter and Mortality in the United States, Using Data Linkage and Bayesian Maximum Entropy

Background: Exposure to fine particulate matter (PM2.5) is an established risk factor for human mortality. However, previous US studies have been limited to select cities or regions or to population subsets (e.g., older adults). Methods: Here, we demonstrate how to use the novel geostatistical method Bayesian maximum entropy to obtain estimates of PM2.5 concentrations in all contiguous US counties, 2000–2016. We then demonstrate how one could use these estimates in a traditional epidemiologic analysis examining the association between PM2.5 and rates of all-cause, cardiovascular, respiratory, and (as a negative control outcome) accidental mortality. Results: We estimated that, for a 1 log(μg/m3) increase in PM2.5 concentration, the conditional all-cause mortality incidence rate ratio (IRR) was 1.029 (95% confidence interval [CI]: 1.006, 1.053). This implies that the rate of all-cause mortality at 10 µg/m3 would be 1.020 times the rate at 5 µg/m3. IRRs were larger for cardiovascular mortality than for all-cause mortality in all gender and race–ethnicity groups. We observed larger IRRs for all-cause, nonaccidental, and respiratory mortality in Black non-Hispanic Americans than White non-Hispanic Americans. However, our negative control analysis indicated the possibility for unmeasured confounding. Conclusion: We used a novel method that allowed us to estimate PM2.5 concentrations in all contiguous US counties and obtained estimates of the association between PM2.5 and mortality comparable to previous studies. Our analysis provides one example of how Bayesian maximum entropy could be used in epidemiologic analyses; future work could explore other ways to use this approach to inform important public health questions

Using animations of risk functions to visualize trends in US all-cause and cause-specific mortality, 1968-2016

Objectives. To use dynamic visualizations of mortality risk functions over both calendar year and age as a way to estimate and visualize patterns in US life spans. Methods. We built 49 synthetic cohorts, 1 per year 1968 to 2016, using National Center for Health Statistics (NCHS) mortality and population data. Within each cohort, we estimated age-specific probabilities of dying from any cause (all-cause analysis) or from a particular cause (cause-specific analysis). We then used Kaplan–Meier (all-cause) or Aalen–Johansen (cause-specific) estimators to obtain risk functions. We illustrated risk functions using time-lapse animations. Results. Median age at death increased from 75 years in 1970 to 83 years in 2015. Risk by age 100 years of cardiovascular mortality decreased (from a risk of 55% in 1970 to 32% in 2015), whereas risk attributable to other (i.e., nonrespiratory and noncardiovascular) causes increased in compensation. Conclusions. Our findings were consistent with the trends published in the NCHS 2015 mortality report, and our dynamic animations added an efficient, interpretable tool for visualizing US mortality trends over age and calendar time

Development and validation of two clinical prediction models to inform clinical decision-making for lumbar spinal fusion surgery for degenerative disorders and rehabilitation following surgery: protocol for a prospective observational study

INTRODUCTION: Potential predictors of poor outcome will be measured at baseline: (1) preoperatively to develop a clinical prediction model to predict which patients are likely to have favourable outcome following lumbar spinal fusion surgery (LSFS) and (2) postoperatively to predict which patients are likely to have favourable long-term outcomes (to inform rehabilitation). METHODS AND ANALYSIS: Prospective observational study with a defined episode inception of the point of surgery. Electronic data will be collected through the British Spine Registry and will include patient-reported outcome measures (eg, Fear-Avoidance Beliefs Questionnaire) and data items (eg, smoking status). Consecutive patients (≥18 years) undergoing LSFS for back and/or leg pain of degenerative cause will be recruited. EXCLUSION CRITERIA: LSFS for spinal fracture, inflammatory disease, malignancy, infection, deformity and revision surgery. 1000 participants will be recruited (n=600 prediction model development, n=400 internal validation derived model; planning 10 events per candidate prognostic factor). The outcome being predicted is an individual's absolute risk of poor outcome (disability and pain) at 6 weeks (objective 1) and 12 months postsurgery (objective 2). Disability and pain will be measured using the Oswestry Disability Index (ODI), and severity of pain in the previous week with a Numerical Rating Scale (NRS 0-10), respectively. Good outcome is defined as a change of 1.7 on the NRS for pain, and a change of 14.3 on the ODI. Both linear and logistic (to dichotomise outcome into low and high risk) multivariable regression models will be fitted and mean differences or ORs for each candidate predictive factor reported. Internal validation of the derived model will use a further set of British Spine Registry data. External validation will be geographical using two spinal registries in The Netherlands and Switzerland. ETHICS AND DISSEMINATION: Ethical approval (University of Birmingham ERN_17-0446A). Dissemination through peer-reviewed journals and conferences

Uneven ground? Intersectional gender inequalities in the commercialized cassava seed system in Tanzania

Open Access JournalCassava (Manihot esculenta Crantz) is an important crop in Africa, especially to women who rely on it as a household staple food and source of income. In Tanzania, a recent move toward commercializing the cassava seed system resulted in significantly fewer women than men farmers, known as Cassava Seed Entrepreneurs (CSEs), producing improved seed for sale to fellow farmers. To document the barriers and constraints that create gender inequalities in the seed system to better understand women’s low representation and experiences in commercialized cassava seed production, we carried out a mixed-methods study in the Southern, Eastern, and Lake Zones of Tanzania in 2021. The quantitative analysis found differences in key individual and household characteristics between CSEs and farmers who aspired to be but did not participate as CSEs (or A-CSEs) as well as between women CSEs and women A-CSEs. After running a logistic regression, results indicated that sex of the farmer (being male) was a statistically significant predictor of participating as a CSE (p < 0.05), along with having a secondary education (p < 0.05) and owning a bank account (p < 0.01). The qualitative analysis highlighted challenges women CSEs face. They spoke about having lower access to and control over prerequisite resources, which are shaped by other intersecting social identities such as marital status and age. Gender stereotypes about their capacities to manage their seed businesses can demotivate them from carrying out their work as well as experiences dealing with discriminatory gender norms that limit their travel to attend trainings outside their communities. Despite these barriers, some women CSEs expressed positive outcomes that have accrued from their participation in commercialized seed production, including enhanced social status and improved living standards. For the commercialized cassava seed system to be more socially inclusive and sustainable, we argue that there is need to adopt gender-aware approaches to address the underlying barriers and biases that exclude women and other social groups. Development efforts should consider combining social change innovations with seed system interventions to address the inequitable norms and power relations that create unique constraints for women to operate effectively as seed entrepreneurs

Usability Guidelines for Desktop Search Engines

In this article we describe a usability evaluation of eight desktop search engines (DSEs). We used the heuristic walkthrough method to gather usability problems as well as individual strengths and weaknesses of the tested search engines. The results of the evaluation are integrated into a set of 30 design guidelines for user-friendly DSEs

Mechanism of polarization of Listeria monocytogenes surface protein ActA

The polar distribution of the ActA protein on the surface of the Gram-positive intracellular bacterial pathogen, Listeria monocytogenes, is required for bacterial actin-based motility and successful infection. ActA spans both the bacterial membrane and the peptidoglycan cell wall. We have directly examined the de novo ActA polarization process in vitro by using an ActA–RFP (red fluorescent protein) fusion. After induction of expression, ActA initially appeared at distinct sites along the sides of bacteria and was then redistributed over the entire cylindrical cell body through helical cell wall growth. The accumulation of ActA at the bacterial poles displayed slower kinetics, occurring over several bacterial generations. ActA accumulated more efficiently at younger, less inert poles, and proper polarization required an optimal balance between protein secretion and bacterial growth rates. Within infected host cells, younger generations of L. monocytogenes initiated motility more quickly than older ones, consistent with our in vitro observations of de novo ActA polarization. We propose a model in which the polarization of ActA, and possibly other Gram-positive cell wall-associated proteins, may be a direct consequence of the differential cell wall growth rates along the bacterium and dependent on the relative rates of protein secretion, protein degradation and bacterial growth