The UoSAT-C,D & E Technology Demonstration Satellites

The University of Surrey (UK) planned a small, inexpensive spacecraft (UoSAT-C) to be launched by NASA on a DELTA launch vehicle as a secondary payload into low-Earth orbit in 1989. This launch has been postponed, but the University has obtained two launch slots on ARIANE. Two spacecraft, UoSATs D & E are currently under construction at The UoSAT Spacecraft Engineering Research Unit at Surrey and they involve collaboration with international experimenters. The spacecraft will carry the majority of the payloads from the postponed UoSAT-C mission. UoSAT-D & E will established by the spacecraft launched NASA, develop further the objectives preceding UoSAT-1 and UoSAT-2 into low Earth, polar orbit by The paper describes the architecture and experiments of the satellite including: Satellite Communications using digital store-&-forward techniques serving remote and under-developed areas and the amateur radio community. Space Technology providing an in-orbit demonstration and operational evaluation of novel technologies and techniques such as transputers and solar cell evaluation. Space Science supporting sophisticated, yet inexpensive space science objectives studying the radiation environment in low Earth orbit such as Cosmic Particle Detection and Radiation Total Dose Measurement

Applications of proxy system modeling in high resolution paleoclimatology

AbstractA proxy system model may be defined as the complete set of forward and mechanistic processes by which the response of a sensor to environmental forcing is recorded and subsequently observed in a material archive. Proxy system modeling complements and sharpens signal interpretations based solely on statistical analyses and transformations; provides the basis for observing network optimization, hypothesis testing, and data-model comparisons for uncertainty estimation; and may be incorporated as weak but mechanistically-plausible constraints into paleoclimatic reconstruction algorithms. Following a review illustrating these applications, we recommend future research pathways, including development of intermediate proxy system models for important sensors, archives, and observations; linking proxy system models to climate system models; hypothesis development and evaluation; more realistic multi-archive, multi-observation network design; examination of proxy system behavior under extreme conditions; and generalized modeling of the total uncertainty in paleoclimate reconstructions derived from paleo-observations

110GHz fT Silicon Bipolar Transistors Implemented using Fluorine Implantation for Boron Diffusion Suppression

This paper investigates how fluorine implantation can be used to suppress boron diffusion in the base of a double polysilicon silicon bipolar transistor and hence deliver a record fT of 110 GHz. Secondary Ion Mass Spectroscopy (SIMS) and transmission electron microscopy are used to characterize the effect of the fluorine implantation energy and dose, the anneal temperature and ambient and the germanium pre-amorphisation implant on the fluorine profiles. These results show that retention of fluorine in the silicon is maximised when a high-energy fluorine implant is combined with a low thermal budget inert anneal. TEM images show that a high-energy fluorine implant into germanium pre-amorphised silicon eliminates the end of range defects from the germanium implant and produces a band of dislocation loops deeper in the silicon at the range of the fluorine implant. Boron SIMS profiles show a suppression of boron diffusion for fluorine doses at and above 5?1014cm-2, but no suppression at lower fluorine doses. This suppression of boron diffusion correlates with the appearance on the SIMS profiles of a fluorine peak at a depth of approximately Rp/2, which is attributed to fluorine trapped in vacancy-fluorine clusters. The introduction of a fluorine implant at this critical fluorine dose into a bipolar transistor process flow leads to an increase in cut-off frequency from 46 to 60GHz. Further optimisation of the base-width and the collector profile leads to a further increase in cut-off frequency to 110GHz. Two factors are postulated to contribute to the suppression of boron diffusion by the fluorine implant. First, the elimination of the germanium end of range defects, and the associated interstitial population, by the fluorine implant, removes a source of transient enhanced diffusion. Second, any interstitials released by the dislocation loops at the range of the fluorine implant would be expected to recombine at the vacancy-fluorine clusters before reaching the boron profile

Perceived discrimination and depressive symptoms among US Latinos: the modifying role of educational attainment

Objective: Despite growing evidence that discrimination may contribute to poor mental health, few studies have assessed this association among US Latinos. Furthermore, the interaction between discrimination and educational attainment in shaping Latino mental health is virtually unexplored. This study aims to examine the association between perceived discrimination and depressive symptoms and the modifying role of education among a population of Mexican-origin adults. Design: We utilized population-based data from 629 Mexican-origin adults (mean age = 52.8 years) participating the Niños Lifestyle and Diabetes Study (2013–2014). Perceived discrimination was defined as responding ‘sometimes’ or ‘often’ to at least one item on the 9-item Everyday Discrimination Scale. High depressive symptoms were defined as scoring ≥10 on the CESD-10. We used log-binomial and linear-binomial models to estimate prevalence ratios (PR) and prevalence differences (PD), respectively, of high depressive symptoms for levels of perceived discrimination. Final models were adjusted for age, sex, education, cultural orientation, and nativity. General estimating equations were employed to account for within-family clustering. Results: Prevalence of perceived discrimination and high depressive symptoms were 49.5% and 29.2%, respectively. Participants experiencing discrimination had higher depressive symptom prevalence than those never or rarely experiencing discrimination [PR = 1.94, 95% confidence interval (CI): 1.46–2.58; PD = 0.19, 95% CI: 0.12–0.27]. The strength of this association varied by education level. The association between discrimination and depressive symptoms was stronger among those with >12 years of education (PR = 2.69; PD = 0.24) compared to those with ≤12 years of education (PR = 1.36; PD = 0.09). Conclusion: US Latinos suffer a high burden of depressive symptoms, and discrimination may be an important driver of this burden. Our results suggest that effortful coping strategies, such as achieving high education despite high perceived discrimination, may magnify discrimination’s adverse effect on Latino mental health

The G-O Rule and Waldmeier Effect in the Variations of the Numbers of Large and Small Sunspot Groups

We have analysed the combined Greenwich and Solar Optical Observing Network (SOON) sunspot group data during the period of 1874-2011 and determined variations in the annual numbers (counts) of the small, large and big sunspot groups (these classifications are made on the basis of the maximum areas of the sunspot groups). We found that the amplitude of an even-numbered cycle of the number of large groups is smaller than that of its immediately following odd-numbered cycle. This is consistent with the well known Gnevyshev and Ohl rule or G-O rule of solar cycles, generally described by using the Zurich sunspot number (Rz). During cycles 12-21 the G-O rule holds good for the variation in the number of small groups also, but it is violated by cycle pair (22, 23) as in the case of Rz. This behaviour of the variations in the small groups is largely responsible for the anomalous behaviour of Rz in cycle pair (22, 23). It is also found that the amplitude of an odd-numbered cycle of the number of small groups is larger than that of its immediately following even-numbered cycle. This can be called as `reverse G-O rule'. In the case of the number of the big groups, both cycle pairs (12, 13) and (22, 23) violated the G-O rule. In many cycles the positions of the peaks of the small, large, and big groups are different and considerably differ with respect to the corresponding positions of the Rz peaks. In the case of cycle 23, the corresponding cycles of the small and large groups are largely symmetric/less asymmetric (Waldmeier effect is weak/absent) with their maxima taking place two years later than that of Rz. The corresponding cycle of the big groups is more asymmetric (strong Waldmeier effect) with its maximum epoch taking place at the same time as that of Rz.Comment: 13 pages, 5 figures, 1 table, accepted by Solar Physic

Spanish Language Use Across Generations and Depressive Symptoms Among US Latinos

Acculturation markers, such as language use, have been associated with Latino depression. Language use may change between generations; however, few studies have collected intergenerational data to assess how language differences between generations impact depression. Using the Niños Lifestyle and Diabetes Study (2013–2014), we assessed how changes in Spanish language use across two generations of Mexican-origin participants in Sacramento, California, influenced offspring depressive symptoms (N = 603). High depressive symptoms were defined as CESD-10 scores ≥ 10. We used log-binomial and linear-binomial models to calculate prevalence ratios and differences, respectively, for depressive symptoms by language use, adjusting for identified confounders and within-family clustering. Decreased Spanish use and stable-equal English/Spanish use across generations protected against depressive symptoms, compared to stable-high Spanish use. Stable-low Spanish use was not associated with fewer depressive symptoms compared to stable-high Spanish use. Exposure to multiple languages cross-generationally may improve resource access and social networks that protect against depression

Neighborhood language isolation and depressive symptoms among elderly U.S. Latinos

Purpose: Neighborhood segregation related to cultural factors, such as language use, may influence elderly Latino depression. We examined the association between neighborhood-level Spanish language segregation and individual depressive symptoms among elderly Latinos. Methods: We linked U.S. Census language use data with geocoded population-based data from 1789 elderly Latinos (mean age = 70.6 years) participating in the Sacramento Area Latino Study on Aging (1998–2008). Neighborhood language segregation was measured with the Index of Concentration at the Extremes, which demonstrates the extent to which residents are concentrated at extremes of deprivation and privilege. We fit two-level generalized linear-mixed models with random intercepts for census tracts to quantify the association between neighborhood-level language segregation and depressive symptoms, adjusting for identified confounders. Results: After adjusting for age, sex, and nativity, residents of highly segregated Spanish-speaking neighborhoods had more depressive symptoms than those in highly segregated English-only-speaking neighborhoods (β = −4.410; 95% confidence interval [CI] = −6.851 to −1.970). This association was largely attenuated upon adjustment for individual-level education (β = −2.119; 95% CI = −4.650 to 0.413). Conclusions: Linguistically segregated communities may benefit from targeted outreach given the high depression prevalence in these neighborhoods. Furthermore, our findings suggest that limited access to fundamental social protections, such as education, may drive the segregation-depression association among U.S. Latinos. © 2018 Elsevier Inc

Educational mobility across generations and depressive symptoms over 10 years among US latinos

Few studies have collected intergenerational data to assess the association between educational mobility across multiple generations and offspring depression. Using data from the Sacramento Area Latino Study on Aging (1998-2008), we assessed the influence of intergenerational education on depressive symptoms over 10 years among 1,786 Latino individuals (mean age = 70.6 years). Educational mobility was classified as stable-low (low parental/low offspring education), upwardly mobile (low parental/high offspring education), stable-high (high parental/ high offspring education), or downwardly mobile (high parental/low offspring education). Depressive symptoms were measured with the Center for Epidemiological Studies-Depression Scale (CES-D); higher scores indicated more depressive symptoms. To quantify the association between educational mobility and CES-D scores over follow-up, we used generalized estimating equations to account for repeated CES-D measurements and adjusted for identified confounders. Within individuals, depressive symptoms remained relatively stable over follow-up. Compared with stable-low education, stable-high education and upward mobility were associated with significantly lower CES-D scores (β = -2.75 and -2.18, respectively). Downwardly mobile participants had slightly lower CES-D scores than stable-low participants (β = -0.77). Our results suggest that sustained, low educational attainment across generations may have adverse mental health consequences, and improved educational opportunities in underresourced communitiesmay counteract the adverse influence of low parental education on Latino depression

Association of food parenting practice patterns with obesogenic dietary intake in Hispanic/Latino youth: Results from the Hispanic Community Children's Health Study/Study of Latino Youth (SOL Youth)

Some food parenting practices (FPPs)are associated with obesogenic dietary intake in non-Hispanic youth, but studies in Hispanics/Latinos are limited. We examined how FPPs relate to obesogenic dietary intake using cross-sectional data from 1214 Hispanic/Latino 8-16-year-olds and their parents/caregivers in the Hispanic Community Children's Health Study/Study of Latino Youth (SOL Youth). Diet was assessed with 2 24-h dietary recalls. Obesogenic items were snack foods, sweets, and high-sugar beverages. Three FPPs (Rules and Limits, Monitoring, and Pressure to Eat)derived from the Parenting strategies for Eating and Activity Scale (PEAS)were assessed. K-means cluster analysis identified 5 groups of parents with similar FPP scores. Survey-weighted multiple logistic regression examined associations of cluster membership with diet. Parents in the controlling (high scores for all FPPs)vs. indulgent (low scores for all FPPs)cluster had a 1.75 (95% CI: 1.02, 3.03)times higher odds of having children with high obesogenic dietary intake. Among parents of 12–16-year-olds, membership in the pressuring (high Pressure to Eat, low Rules and Limits and Monitoring scores)vs. indulgent cluster was associated with a 2.96 (95% CI: 1.51, 5.80)times greater odds of high obesogenic dietary intake. All other associations were null. Future longitudinal examinations of FPPs are needed to determine temporal associations with obesogenic dietary intake in Hispanic/Latino youth