151 research outputs found
On orbit surfacing of thermal control surfaces
Substrates to be contaminated and contamination source were prepared. Additional information on paint spray method apparatus was obtained. Silver teflon second surface mirror samples and S 13 GLO paint samples were mounted, photographed under the microscope and measured to establish baseline data. Atomic oxygen cleaning and spray painting are being considered. Electrostatic powder and plasma spray coating systems appear to have serious drawbacks
Laboratory studies of silicon vapor deposition, phase A
A system is described capable of carrying out silicon vapor deposition experiments in the low 10 to the minus 10th power torr vacuum range. The system was assembled and tested for use in a program aimed at exploration of vacuum heteroepitaxy of silicon on several substrates of potential interest for photovoltaic applications. An experiment is described in which a silicon layer 2.5 microns thick was deposited on a pyrolytically cleaned tungsten substrate held at a temperature of 400 C. Using a resistance heated silicon source, thicker layers can be deposited in periods of hours by utilizing closer source to substrate distances
Pressure Modulator Radiometer (PMR) tests
The pressure modulator technique was evaluated for monitoring pollutant gases in the Earth's atmosphere of altitude levels corresponding to the mid and lower troposphere. Using an experimental set up and a 110 cm sample cell, pressure modulator output signals resulting from a range of gas concentrations in the sample cell were examined. Then a 20 cm sample cell was modified so that trace gas properties in the atmosphere could be simulated in the laboratory. These gas properties were measured using an infrared sensor
Four Work-Ins by Australian Journalists, 1944-80
During industrial disputes with employers between 1944 and 1980 the Australian Journalist's Association occasionally turned to the tactic of the work-in, producing wild cat newspapers during strikes in Sydney. These newspapers (The News, and The Clarion) exemplified problematic elements of the work-in as a working-class strategy. While single incident studies of the work-in have been conducted in Australia, the Australian Journalist Association work-ins present a time series of struggle. This time series allows for a broader evaluation of the radical content of the work-in and indicates that the tactic can become systematised, less radical, and less participatory when not connected to a broader generation of workplace radical behaviour by workers. In short: the work-in, much like the strike or go slow, can become a tame cat tactic – it is not inherently transgressive or opposed to capitalist production. Expectedly, the first work-ins were more radical in scope, presenting a newspaper which fully duplicated the commodity produced under capitalist control and in some ways exceeded the scope presented by capitalist organised journalism in both a material and a cultural sense. However, this radical economic potential dissipated by the end of the time series of work-ins. Instead of providing an alternative commodity fit for market, the tactic produced propaganda pieces aimed primarily at the members of the community who would be predisposed to favour the journalist's case. The 1980s Clarion was not a daily newspaper of news, sport, racing, women's interest, classifieds, and general opinion. This change will be explained in terms of human causes such as skills loss, production process causes such as computerisation and wire services, and broader social causes such as the changing role of the newspaper in Australian society.The symposium is organised on behalf of AAHANZBS by the Business and Labour History Group, The University of Sydney, with the financial support of the University’s Faculty of Economics and Business
Physical activity and fat-free mass during growth and in later life
Physical activity may be a way to increase and maintain fat-free mass (FFM) in later life, similar to the prevention of fractures by increasing peak bone mass.A study is presented of the association between FFM and physical activity in relation to age.In a cross-sectional study, FFM was analyzed in relation to physical activity in a large participant group as compiled in the International Atomic Energy Agency Doubly Labeled Water database. The database included 2000 participants, age 3–96 y, with measurements of total energy expenditure (TEE) and resting energy expenditure (REE) to allow calculation of physical activity level (PAL = TEE/REE), and calculation of FFM from isotope dilution.PAL was a main determinant of body composition at all ages. Models with age, fat mass (FM), and PAL explained 76\% and 85\% of the variation in FFM in females and males < 18 y old, and 32\% and 47\% of the variation in FFM in females and males ≥ 18 y old, respectively. In participants < 18 y old, mean FM-adjusted FFM was 1.7 kg (95\% CI: 0.1, 3.2 kg) and 3.4 kg (95\% CI: 1.0, 5.6 kg) higher in a very active participant with PAL = 2.0 than in a sedentary participant with PAL = 1.5, for females and males, respectively. At age 18 y, height and FM–adjusted FFM was 3.6 kg (95\% CI: 2.8, 4.4 kg) and 4.4 kg (95\% CI: 3.2, 5.7 kg) higher, and at age 80 y 0.7 kg (95\% CI: −0.2, 1.7 kg) and 1.0 kg (95\% CI: −0.1, 2.1 kg) higher, in a participant with PAL = 2.0 than in a participant with PAL = 1.5, for females and males, respectively.If these associations are causal, they suggest physical activity is a major determinant of body composition as reflected in peak FFM, and that a physically active lifestyle can only partly protect against loss of FFM in aging adults
Human total, basal and activity energy expenditures are independent of ambient environmental temperature
ower ambient temperature (Ta) requires greater energy expenditure to sustain body temperature. However, effects of Ta on human energetics may be buffered by environmental modification and behavioral compensation. We used the IAEA DLW database for adults in the USA (n = 3213) to determine the effect of Ta (−10 to +30°C) on TEE, basal (BEE) and activity energy expenditure (AEE) and physical activity level (PAL). There were no significant relationships (p > 0.05) between maximum, minimum and average Ta and TEE, BEE, AEE and PAL. After adjustment for fat-free mass, fat mass and age, statistically significant (p < 0.01) relationships between TEE, BEE and Ta emerged in females but the effect sizes were not biologically meaningful. Temperatures inside buildings are regulated at 18–25°C independent of latitude. Hence, adults in the US modify their environments to keep TEE constant across a wide range of external ambient temperatures
The Gly2019Ser mutation in LRRK2 is not fully penetrant in familial Parkinson's disease: the GenePD study
<p>Abstract</p> <p>Background</p> <p>We report age-dependent penetrance estimates for leucine-rich repeat kinase 2 (<it>LRRK2</it>)-related Parkinson's disease (PD) in a large sample of familial PD. The most frequently seen <it>LRRK2 </it>mutation, Gly2019Ser (G2019S), is associated with approximately 5 to 6% of familial PD cases and 1 to 2% of idiopathic cases, making it the most common known genetic cause of PD. Studies of the penetrance of <it>LRRK2 </it>mutations have produced a wide range of estimates, possibly due to differences in study design and recruitment, including in particular differences between samples of familial PD versus sporadic PD.</p> <p>Methods</p> <p>A sample, including 903 affected and 58 unaffected members from 509 families ascertained for having two or more PD-affected members, 126 randomly ascertained PD patients and 197 controls, was screened for five different <it>LRRK2 </it>mutations. Penetrance was estimated in families of <it>LRRK2 </it>carriers with consideration of the inherent bias towards increased penetrance in a familial sample.</p> <p>Results</p> <p>Thirty-one out of 509 families with multiple cases of PD (6.1%) were found to have 58 <it>LRRK2 </it>mutation carriers (6.4%). Twenty-nine of the 31 families had G2019S mutations while two had R1441C mutations. No mutations were identified among controls or unaffected relatives of PD cases. Nine PD-affected relatives of G2019S carriers did not carry the <it>LRRK2 </it>mutation themselves. At the maximum observed age range of 90 to 94 years, the unbiased estimated penetrance was 67% for G2019S families, compared with a baseline PD risk of 17% seen in the non-<it>LRRK2</it>-related PD families.</p> <p>Conclusion</p> <p>Lifetime penetrance of <it>LRRK2 </it>estimated in the unascertained relatives of multiplex PD families is greater than that reported in studies of sporadically ascertained <it>LRRK2 </it>cases, suggesting that inherited susceptibility factors may modify the penetrance of <it>LRRK2 </it>mutations. In addition, the presence of nine PD phenocopies in the <it>LRRK2 </it>families suggests that these susceptibility factors may also increase the risk of non-<it>LRRK2</it>-related PD. No differences in penetrance were found between men and women, suggesting that the factors that influence penetrance for <it>LRRK2 </it>carriers are independent of the factors which increase PD prevalence in men.</p
Acquired and congenital disorders of sung performance: A review.
Many believe that the majority of people are unable to carry a tune. Yet, this
widespread idea underestimates the singing abilities of the layman. Most
occasional singers can sing in tune and in time, provided that they perform at a
slow tempo. Here we characterize proficient singing in the general population
and identify its neuronal underpinnings by reviewing behavioral and neuroimaging
studies. In addition, poor singing resulting from a brain injury or neurogenetic
disorder (i.e., tone deafness or congenital amusia) is examined. Different lines
of evidence converge in indicating that poor singing is not a monolithic
deficit. A variety of poor-singing "phenotypes" are described,
with or without concurrent perceptual deficits. In addition, particular
attention is paid to the dissociations between specific abilities in poor
singers (e.g., production of absolute vs. relative pitch, pitch vs. time
accuracy). Such diversity of impairments in poor singers can be traced to
different faulty mechanisms within the vocal sensorimotor loop, such as pitch
perception and sensorimotor integration
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