1,252 research outputs found
Laminar-flow flight experiments
The flight testing conducted over the past 10 years in the NASA laminar-flow control (LFC) will be reviewed. The LFC program was directed towards the most challenging technology application, the high supersonic speed transport. To place these recent experiences in perspective, earlier important flight tests will first be reviewed to recall the lessons learned at that time
Testing the impact of an educational intervention designed to promote ocular health among people with age-related macular degeneration
Research has shown that individuals affected by age-related macular degeneration (AMD) do not always consume foods or supplements known to be beneficial for ocular health. This study tested the effectiveness of an educational intervention designed to promote healthy eating and nutritional supplementation in this group. A total of 100 individuals with AMD completed baseline measures of several variables: confidence that diet affects AMD, motivation to engage in health-protective behaviours, knowledge about which nutrients are beneficial, and intake of kale, spinach, and eggs. Participants were allocated to either intervention or control conditions. Intervention participants received a leaflet and prompt card that contained advice regarding dietary modification and supplementation. Control participants received a leaflet created by the Royal College of Optometrists. A follow-up questionnaire, measuring the same variables assessed at baseline, was administered 2 weeks later. At follow-up, significant condition × time interactions were found for confidence that diet affects AMD (F(1, 92) = 4.54, p < .05), motivation to talk to an eye professional about supplementation (F(1, 92) = 4.53, p = .036), motivation to eat eggs (F(1, 92) = 12.67, p = .001), and egg intake (F(1, 92) = 11.97, p = .001). In each case, intervention participants scored higher than control participants. Receiving an educational intervention increased participants’ confidence that diet affects AMD, motivation to engage in health-protective behaviours, and egg intake. This intervention could be easily incorporated into current clinical practice delivered by either optometrists or ophthalmologists
Macular pigment optical density is related to blood glutathione levels in healthy individuals
Purpose. To assess the relationship between macular pigment optical density (MPOD) and blood markers for antioxidant defense in otherwise healthy volunteers. Methods. Forty-seven healthy volunteers were subjected to blood analysis to detect the level of circulating glutathione in its reduced (GSH) and oxidized (GSSG) forms. The level of MPOD was measured using heterochromatic flicker photometry. Systemic blood pressure (BP) parameters, heart rate (HR), body mass index (BMI), and plasma levels of total, HDL, and LDL cholesterol and triglycerides (TGs) were also determined. Results. A simple correlation model revealed that the level of MPOD correlated significantly and positively with both GSH (P 0.05). Age, sex, systemic BP parameters, HR, BMI, and plasma levels of cholesterol and TGs did not have any influence on either MPOD or glutathione levels (all P > 0.05). In addition, a forward stepwise multiple regression analysis showed MPOD to have a significantly and independent correlation with GSH levels (ß = 0.63; P < 0.001). Conclusions. In otherwise healthy older individuals, there is a positive correlation between local and systemic antioxidant defense mechanisms
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Expansion of Thaumarchaeota habitat range is correlated with horizontal transfer of ATPase operons.
Thaumarchaeota are responsible for a significant fraction of ammonia oxidation in the oceans and in soils that range from alkaline to acidic. However, the adaptive mechanisms underpinning their habitat expansion remain poorly understood. Here we show that expansion into acidic soils and the high pressures of the hadopelagic zone of the oceans is tightly linked to the acquisition of a variant of the energy-yielding ATPases via horizontal transfer. Whereas the ATPase genealogy of neutrophilic Thaumarchaeota is congruent with their organismal genealogy inferred from concatenated conserved proteins, a common clade of V-type ATPases unites phylogenetically distinct clades of acidophilic/acid-tolerant and piezophilic/piezotolerant species. A presumptive function of pumping cytoplasmic protons at low pH is consistent with the experimentally observed increased expression of the V-ATPase in an acid-tolerant thaumarchaeote at low pH. Consistently, heterologous expression of the thaumarchaeotal V-ATPase significantly increased the growth rate of E. coli at low pH. Its adaptive significance to growth in ocean trenches may relate to pressure-related changes in membrane structure in which this complex molecular machine must function. Together, our findings reveal that the habitat expansion of Thaumarchaeota is tightly correlated with extensive horizontal transfer of atp operons
Primordial Nucleosynthesis with CMB Inputs: Probing the Early Universe and Light Element Astrophysics
Cosmic microwave background (CMB) determinations of the baryon-to-photon
ratio will remove the last free
parameter from (standard) big bang nucleosynthesis (BBN) calculations. This
will make BBN a much sharper probe of early universe physics, for example,
greatly refining the BBN measurement of the effective number of light neutrino
species, . We show how the CMB can improve this limit, given
current light element data. Moreover, it will become possible to constrain
independent of \he4, by using other elements, notably deuterium;
this will allow for sharper limits and tests of systematics. For example, a 3%
measurement of , together with a 10% (3%) measurement of primordial D/H,
can measure to a 95% confidence level of \sigma_{95%}(N_\nu) =
1.8 (1.0) if . If instead, one adopts the
standard model value , then one can use (and its
uncertainty) from the CMB to make accurate predictions for the primordial
abundances. These determinations can in turn become key inputs in the
nucleosynthesis history (chemical evolution) of galaxies thereby placing
constraints on such models.Comment: 17 pages, 13 figures, plain LaTe
Necessary fictions: indigenous claims and the humanity of rights
Indigenous right insistently challenges the surpassing arrogations of sovereign right. In so doing, it affirms dimensions of being-together denied or stunted in sovereign modes of political formation. This force of Indigenous right is amplified here through legal and literary instantiations. These, in turn, uncover the continuously created and fictional quality of rights, revealing them to be necessary fictions
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