1,152 research outputs found
The landing task and pilot acceptance of displays for landing in reduced weather minimums
Landing task and pilot acceptance of displays for landing in reduced weather minim
Some NASA contributions to human factors engineering: A survey
This survey presents the NASA contributions to the state of the art of human factors engineering, and indicates that these contributions have a variety of applications to nonaerospace activities. Emphasis is placed on contributions relative to man's sensory, motor, decisionmaking, and cognitive behavior and on applications that advance human factors technology
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The Historiography of the Twentieth-Century Classical Performer: Life, Work, Artistry
AbstractOne dominant issue in the writing of music histories is the question of how (or indeed whether) a musician's life and work can be interwoven convincingly. In recent years, music biographers have begun to reassess the historical legacies of many significant musicians with this issue in mind, but their critical reflections have for the most part focused on composers. This article seeks to transfer some of this rethinking – particularly on the life/work question – to the twentieth-century classical performer. Doing so reveals a historiography of the performer which sharply divides life and work in a way that is disciplinarily entrenched between biographical approaches on the one hand and empirical approaches to recordings on the other. After illustrating the nature and development of this division, I conclude by calling for greater scholarly convergence and suggest two directions forward, taking leads from artistic research and popular music studies in doing so.</jats:p
Carrier-induced ferromagnetism in n-type ZnMnAlO and ZnCoAlO thin films at room temperature
The realization of semiconductors that are ferromagnetic above room
temperature will potentially lead to a new generation of spintronic devices
with revolutionary electrical and optical properties. Transition temperatures
in doped ZnO are high but, particularly for Mn doping, the reported moments
have been small. We show that by careful control of both oxygen deficiency and
aluminium doping the ferromagnetic moments measured at room temperature in
n-type ZnMnO and ZnCoO are close to the ideal values of 5mB and 3mB
respectively. Furthermore a clear correlation between the magnetisation per
transition metal ion and the ratio of the number of carriers to the number of
transition metal donors was established as is expected for carrier induced
ferromagnetism for both the Mn and Co doped films. The dependence of the
magnetisation on carrier density is similar to that predicted for the
transition temperature for a dilute magnetic semiconductor in which the
exchange between the transition metal ions is through the free carriers.Comment: 14 pages pd
Spin polarized transport current in n-type co-doped ZnO thin films measured by Andreev spectroscopy
We use point contact Andreev reflection measurements to determine the spin
polarization of the transport current in pulse laser deposited thin films of
ZnO with 1% Al and with and without 2%Mn. Only films with Mn are ferromagnetic
and show spin polarization of the transport current of up to 55 0.5% at
4.2 K, in sharp contrast to measurements of the nonmagnetic films without Mn
where the polarization is consistent with zero. Our results imply strongly that
ferromagnetism in these Al doped ZnO films requires the presence of Mn.Comment: Published versio
Socioeconomic inequalities in duration of untreated psychosis : evidence from administrative data in England
Background. Duration of untreated psychosis (DUP) is an important measure of access to care as it predicts prognosis and treatment outcomes. Little is known about potential socioeconomic inequalities in DUP. The aim of this study was to investigate inequalities in DUP associated with socioeconomic deprivation in a national cohort in England. Method. We analysed a cohort of 887 patients with a first-episode in psychosis using the administrative Mental Health Services Dataset in England. We used a Generalised Linear Model to account for non-linearity in DUP and looked at inequalities across the whole distribution of DUP using quantile regression. Results. The median DUP was 22 days (mean = 74 days) with considerable variations between and within the 31 hospital providers. We found evidence of significant inequalities regarding the level of socioeconomic deprivation. Patients living in the second, third, and fourth deprived neighbourhood quintiles faced a 36, 24, and 31 day longer DUP than patients from the least deprived neighbourhoods. Inequalities were more prevalent in higher quantiles of the DUP distribution. Unemployment prolonged DUP by 40 days. Having been in contact with mental health care services prior to the psychosis start significantly reduced the DUP by up to 53 days. Conclusions. Socioeconomic deprivation is an important factor in explaining inequalities in DUP. Policies to improve equitable access to care should particularly focus on preventing very long delays in treatment and target unemployed patients as well as people that have not been in contact with any mental health professional in the past
Alpha-linolenic acid supplementation in Tris extender can improve frozen–thawed bull semen quality
The study was conducted to evaluate the effects of α-linolenic acid (ALA) on frozen–thawed quality and fatty acid composition of bull sperm. For that, twenty-four ejaculates obtained from three bulls were diluted in a Tris extender containing 0 (control), 3, 5, 10 and 15 ng/ml of ALA. Extended semen was incubated at 37°C for 15 min, to allow absorption of ALA by sperm cell membrane. The sample was chilled for 2 h, packed into 0.25-ml straws and frozen in liquid nitrogen for 24 h. Subsequently, straws were thawed and evaluated for total sperm motility (computer-assisted semen analysis), membrane functional integrity (hypo-osmotic swelling test), viability (eosin-nigrosin), fatty acid composition (gas chromatography) and lipid peroxidation (thiobarbituric acid-reactive substances (TBARS)). A higher (p < 0.05) percentage of total sperm motility was observed in ALA groups 5 ng/ml (47.74 ± 07) and 10 ng/ml (44.90 ± 0.7) in comparison with control (34.53 ± 3.0), 3 ng/ml (34.40 ± 2.6) and 15 ng/ml (34.60 ± 2.9). Still, the 5 ng/ml ALA group presented a higher (p < 0.05) percentage of viable sperms (74.13 ± 0.8) and sperms with intact membrane (74.46 ± 09) than all other experimental groups. ALA concentration and lipid peroxidation in post-thawed sperm was higher in all treated groups when compared to the control group. As such, the addition of 5 ng/ml of ALA to Tris extender improved quality of frozen–thawed bull spermatozoa
The dose-response of the nordic hamstring exercise on biceps femoris architecture and eccentric knee flexor strength : A randomized interventional trial
Purpose: To examine the dose–response of the Nordic hamstring exercise (NHE) on biceps femoris long head (BFlh) architecture and eccentric knee flexor strength. Design: Randomized interventional trial. Methods: Forty recreationally active males completed a 6-week NHE training program consisting of either intermittent low volumes (group 1; n = 10), low volumes (group 2; n = 10), initial high volumes followed by low volumes (group 3; n = 10), or progressively increasing volumes (group 4; n = 10). A 4-week detraining period followed each program. Muscle architecture was assessed weekly during training and after 2 and 4 weeks of detraining. Eccentric knee flexor strength was assessed preintervention and postintervention and after 2 and 4 weeks of detraining. Results: Following 6 weeks of training, BFlh fascicle length (FL) increased in group 3 (mean difference = 0.83 cm, d = 0.45, P = .027, +7%) and group 4 (mean difference = 1.48 cm, d = 0.94, P = .004, +14%). FL returned to baseline following detraining in groups 3 and 4. Strength increased in group 2 (mean difference = 53.6 N, d = 0.55, P = .002, +14%), group 3 (mean difference = 63.4 N, d = 0.72, P = .027, +17%), and group 4 (mean difference = 74.7, d = 0.83, P = .006, +19%) following training. Strength returned to baseline following detraining in groups 2 and 3 but not in group 4. Conclusions: Initial high volumes of the NHE followed by lower volumes, as well as progressively increasing volumes, can elicit increases in BFlh FL and eccentric knee flexor strength. Low volumes of the NHE were insufficient to increase FL, although as few as 48 repetitions in 6 weeks did increase strength
Do PGI integrated farms perform better? The case of the beef farms in Spain
European rural development policy is gaining in importance through one of its key instruments, the Protected Geographical Indications (PGI) system, which is designed to improve quality standards. Previous research has shown that PGI-certified beef farms tend to be more extensively managed operations that are better adapted to mountainous areas. This paper describes a comparative study of two production systems, one with PGI certification and one without, focusing on a number of economic variables. The results show a positive association between PGI production and profitability. In efficiency terms, non-certified farms show better pure technical efficiency scores, while PGI-certified holdings score higher on scale efficiency
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