Development of an improved toughness hyperpure silica reflective heat shield

High purity three dimensionally woven silica-silica materials were evaluated for use as a tough reflective heat shield for planetary entry probes. A special weave design was selected to minimize light piping effects through the heat shield thickness. Various weave spacings were evaluated for densification efficiency with an 0.7 micron particle size high purity silica. Spectral hemispherical reflectance was measured from 0.2 to 2.5 microns at room temperature. Reflectance increases due to densification and purity of material were measured. Reflectance of 3D hyperpure silica was higher than 3D astroquartz silica for all wavelengths. Mechanical properties were measured in beam flexure and beam shear tests. Results indicated strengths lower than reported for slip cast fused silica. Low strengths were attributed to low densities achieved through vacuum impregnation

Genetic Contributions of desatF and eloF to Courtship Mating Behavior and Cuticular Hydrocarbon Production in Drosophila simulans and D. sechellia

Sexual isolation occurs between Drosophila simulans and D. sechellia due to differences in cuticular hydrocarbon (CHC) productions. A wide variety of hydrocarbons are produced, but D. simulans males and females predominantly produce 7-tricosene (7-T), a 23 carbon monoene, while D. sechellia males produce 7-T and D. sechellia females produce 7,11-heptacosadiene (7,11-HD), a 27 carbon diene (Coyne et al. 1994). An asymmetric mating pattern occurs due to hydrocarbon differences: D. simulans males only court D. simulans females and D. sechellia males court both D. simulans and D. sechellia females (Cobb and Jallon 1990). Previous quantitative trait locus (QTL) studies (Gleason et al. 2005; Gleason et al. 2009) identified desatF and eloF as candidate genes contributing to production of D. sechellia pheromone 7,11-HD. In this thesis, the effect of D. sechellia alleles in a D. simulans background is measured for desatF and eloF by (1) monitoring mating behavior response through copulation success and latency and (2) identifying the differences in CHC biosynthesis through elongation and desaturation changes. Behavioral analyses indicated that there was no significant effect on courtship for the genes independently. Analysis of CHC production differences indicates a more pronounced effect of desatF and eloF on pheromone biosynthesis. In elongation from 23 to 25 carbons, females carrying the eloF gene produced increased amounts of 7-pentacosene, indicating eloF effects hydrocarbon elongation. Absence of further elongation to 27 carbons suggests involvement of other elongases for synthesis to 7,11-HD. Females carrying the desatF gene produced increased amounts of 7,11-pentacosadiene, indicating desatF is responsible for increasing dienes. Only when females carried D. sechellia alleles at both loci did production of 7,11-HD occur. However, the amount of 7,11-HD was significantly lower than amounts produced by D. sechellia females. Evidence from this study indicates desatF and eloF are genes present in the hydrocarbon biosynthesis pathway and are probably necessary for female D. sechellia pheromone production. However, D. sechellia alleles of desatF and eloF are not sufficient for production of 7,11-HD indicating involvement of other biosynthesis genes to fully produce the D. sechellia female pheromone

John David Mongin (1763-1833)

The revocation of the Edict of Nantes in 1685 brought about the persecution of protestants in France. By 1725 the persecution of the Hugenots became intolerable and so a thirty five year old watchmaker named David John Mongin (grandfather of John David Mongin) and his brother Francis left France. Their departure was not a moment to soon as can be shown by the following account from the family bible.https://digitalcommons.georgiasouthern.edu/sav-bios-lane/1178/thumbnail.jp

Machine learning with the hierarchy‐of‐hypotheses (HoH) approach discovers novel pattern in studies on biological invasions

Research synthesis on simple yet general hypotheses and ideas is challenging in scientific disciplines studying highly context‐dependent systems such as medical, social, and biological sciences. This study shows that machine learning, equation‐free statistical modeling of artificial intelligence, is a promising synthesis tool for discovering novel patterns and the source of controversy in a general hypothesis. We apply a decision tree algorithm, assuming that evidence from various contexts can be adequately integrated in a hierarchically nested structure. As a case study, we analyzed 163 articles that studied a prominent hypothesis in invasion biology, the enemy release hypothesis. We explored if any of the nine attributes that classify each study can differentiate conclusions as classification problem. Results corroborated that machine learning can be useful for research synthesis, as the algorithm could detect patterns that had been already focused in previous narrative reviews. Compared with the previous synthesis study that assessed the same evidence collection based on experts' judgement, the algorithm has newly proposed that the studies focusing on Asian regions mostly supported the hypothesis, suggesting that more detailed investigations in these regions can enhance our understanding of the hypothesis. We suggest that machine learning algorithms can be a promising synthesis tool especially where studies (a) reformulate a general hypothesis from different perspectives, (b) use different methods or variables, or (c) report insufficient information for conducting meta‐analyses

Wilson loops, geometric operators and fermions in 3d group field theory

Group field theories whose Feynman diagrams describe 3d gravity with a varying configuration of Wilson loop observables and 3d gravity with volume observables at each vertex are defined. The volume observables are created by the usual spin network grasping operators which require the introduction of vector fields on the group. We then use this to define group field theories that give a previously defined spin foam model for fermion fields coupled to gravity, and the simpler quenched approximation, by using tensor fields on the group. The group field theory naturally includes the sum over fermionic loops at each order of the perturbation theory.Comment: 13 pages, many figures, uses psfra

Retention of Calcium Oxalate Crystals in Renal Tubules

Crystal retention within the renal tubules is essential for nephrolithiasis and the development of urinary stone disease. We studied the mechanisms involved in this process by inducing calcium oxalate crystal deposition within the rat renal tubules and examining them using various microscopic techniques. Crystals appeared to be retained either by attachment to the tubular epithelium or by aggregating with other crystals thus becoming large enough to be retained by their collective size

Ka-band Ga-As FET noise receiver/device development

The development of technology for a 30 GHz low noise receiver utilizing GaAs FET devices exclusively is discussed. This program required single and dual-gate FET devices, low noise FET amplifiers, dual-gate FET mixers, and FET oscillators operating at Ka-band frequencies. A 0.25 micrometer gate FET device, developed with a minimum noise figure of 3.3 dB at 29 GHz and an associated gain of 7.4 dB, was used to fabricate a 3-stage amplifier with a minimum noise figure and associated gain of 4.4 dB and 17 dB, respectively. The 1-dB gain bandwidth of this amplifier extended from below 26.5 GHz to 30.5 GHz. A dual-gate mixer with a 2 dB conversion loss and a minimum noise figure of 10 dB at 29 GHz as well as a dielectric resonator stabilized FET oscillator at 25 GHz for the receiver L0. From these components, a hybrid microwave integrated circuit receiver was constructed which demonstrates a minimum single-side band noise figure of 4.6 dB at 29 GHz with a conversion gain of 17 dB. The output power at the 1-dB gain compression point was -5 dBm

Enjoyment of life predicts reduced type 2 diabetes incidence over 12 years of follow-up: findings from the English Longitudinal Study of Ageing

BACKGROUND: Subjective well-being appears to be associated with reduced risk of type 2 diabetes (T2D). However, it is unknown whether this association is similar across different types of well-being. We examined the relationship between hedonic and eudaimonic well-being and incident T2D, and explored the role of sociodemographic, behavioural and clinical factors in these associations. METHODS: We used data from 4134 diabetes-free participants from the English Longitudinal Study of Ageing (mean age =64.97). Enjoyment of life and purpose in life were assessed using items from the CASP-19 to reflect hedonic and eudaimonic well-being, respectively. Participants reported T2D diagnosis over 12 years. We used Cox proportional hazards regression analyses and also explored the percentage of association explained by different covariates. RESULTS: Results revealed a protective role for enjoyment of life in T2D rate adjusting for sociodemographic (age, sex, wealth, ethnicity, marital status), behavioural (physical activity, smoking, alcohol consumption, body mass index) and clinical (hypertension, coronary heart disease and glycated haemoglobin) characteristics (HR =0.93, p=0.021, 95% CI (0.87, 0.99)). Sociodemographic, behavioural and clinical factors accounted for 27%, 27% and 18% of the association, respectively. The relationship between purpose in life and T2D was non-significant (adjusted HR =0.92, p=0.288, 95% CI (0.78, 1.08)). CONCLUSION: This study illustrates how the link between subjective well-being and T2D varies between well-being components. It also demonstrates that sociodemographic, behavioural and clinical factors partially explain this association. Intervention studies examining whether changes in enjoyment of life can help delay T2D onset are warranted

Histochemistry of Colloidal Iron Stained Crystal Associated Material in Urinary Stones and Experimentally Induced Intrarenal Deposits in Rats

Organic material associated with the calcium oxalate crystals in urinary stones and experimentally induced nephrolithiasis was stained with colloidal iron and analysed by energy dispersive x-ray microanalysis using standard techniques. Iron was positively identified in the stained specimens indicating that some of the organic material is an acidic mucosubstance. The results also indicate that some of the organic material of urinary stones may originate in the kidneys

Presence of Calcium Oxalate Crystals in the Mammalian Thyroid Gland

Birefringent crystals of calcium oxalate have been previously identified in the colloid of human thyroid glands. We found such crystals in 19/20 adult thyroids at autopsy, in 4/ 20 infants at autopsy, and, using frozen sections, in 19/20 thyroids partially or totally removed at surgery. These crystals were soluble in hydrochloric acid, insoluble in acetic acid, and contained only calcium by energy dispersive X-ray microanalysis, confirming their calcium oxalate character. Similar crystals were found in equine and ovine thyroids