5,544 research outputs found
The role of proton precipitation in Jovian aurora: Theory and observation
It was proposed that the Jovian auroral emissions observed by Voyager spacecraft could be explained by energetic protons precipitating into the upper atmosphere of Jupiter. Such precipitation of energetic protons results in Doppler-shifted Lyman alpha emission that can be quantitatively analyzed to determine the energy flux and energy distribution of the incoming particle beam. Modeling of the expected emission from a reasonably chosen Voyager energetic proton spectrum can be used in conjunction with International Ultraviolet Explorer (IUE) observations, which show a relative lack of red-shifted Lyman alpha emission, to set upper limits on the amount of proton precipitation taking place in the Jovian aurora. Such calculations indicate that less than 10 percent of the ultraviolet auroral emissions at Jupiter can be explained by proton precipitation
Electrophysiological correlates of high-level perception during spatial navigation
We studied the electrophysiological basis of object recognition by recording scalp\ud
electroencephalograms while participants played a virtual-reality taxi driver game.\ud
Participants searched for passengers and stores during virtual navigation in simulated\ud
towns. We compared oscillatory brain activity in response to store views that were targets or\ud
nontargets (during store search) or neutral (during passenger search). Even though store\ud
category was solely defined by task context (rather than by sensory cues), frontal ...\ud
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Age Distribution of Lunar Impact-Melt Rocks in Apollo Drive-Tube 68001/2
Apollo 16 double-drive tube 68001 /68002 provides impact and volcanic materials along a depth of approximately 60 cm in five compositional distinct units. 68001 /2 offers the potential to study distinct populations of impact melts with depth to understand how 'gardening' affects these samples. We will use unbiased major-element chemistry, mineralogy, and age to understand the impact history of Apollo 16 landing site. The study demonstrates the techniques that landed missions require to identify lithologies of interest (e.g., impact melts)
Notes
Notes by Sidney Baker, James D. Matthews, Henry M. Shine, Arthur B. Curran, Jr., William G. Mahoney, Jr., and James W. Oberfell
Tackling mental health: the role of professional football clubs
In the UK, professional football clubs are being used as settings for the delivery of interventions that promote mental health in a number of ways including (i) the delivery of physical activity interventions to improve the mental health of the general population, (ii) the delivery of physical activity interventions for people experiencing mental illness, and (iii) the delivery of community mental health services within the confines of the football club. This research note offers insights into mental health interventions delivered within, and by, professional football clubs and the available evidence concerning their reach, effectiveness and impact. The findings suggest that professional football clubs can help to facilitate access to mental health services, particularly among young people, for whom accessing such services may be highly stigmatized. Furthermore, the findings highlight that such interventions have a positive impact on health. However, in order to capitalize on this opportunity funding agencies and commissioners must provide appropriate resources (human and financial) for effective delivery and evaluation. Furthermore, a more strategic approach to working towards the mental health agenda must be adopted. It is argued that this change in practice would allow professional football clubs to offer those in need access to high-quality interventions
Oral Mutian®X stopped faecal feline coronavirus shedding by naturally infected cats
Feline coronavirus (FCoV) is common among cats living indoors in groups. In about 10% of infected cats, a potentially lethal disease, feline infectious peritonitis (FIP) occurs. Virus transmission is faecal-oral. Mutian® Xraphconn (Mutian X) is a product marketed to treat cats with FIP but is also being used to stop virus shedding, although no clear guidelines exist for its use for this purpose. The aim of this study was to establish the minimum dose and treatment duration required to ensure viral clearance from the faeces of asymptomatic virus-shedding cats. In five multicat households, 29 cats naturally infected with FCoV and actively shedding virus in the faeces were given Mutian X pills. Virus shedding was monitored using reverse-transcription quantitative polymerase chain reaction (RT-qPCR) controlled for faecal inhibitors to ensure sensitivity. Mutian X given orally cleared the virus in 29 cats; although four cats required a repeated course to finally stop virus shedding. A dose of 4 mg/kg q24 h for four days was found to be the optimal treatment protocol: 2 mg/kg cleared only 80% of cats. Post-treatment using a sensitive RT-qPCR test was essential to ensure that virus clearance had been achieved, since failure to clear even one cat can result in re-infection of the others. Records of virus shedding by cats before treatment provided a retrospective control: significantly more cats stopped shedding virus after Mutian X than recovered from infection during the control period (p < .00001). This is the first report of the successful elimination of faecal FCoV shedding in chronically infected cats
Open-Ended Evolutionary Robotics: an Information Theoretic Approach
This paper is concerned with designing self-driven fitness functions for
Embedded Evolutionary Robotics. The proposed approach considers the entropy of
the sensori-motor stream generated by the robot controller. This entropy is
computed using unsupervised learning; its maximization, achieved by an on-board
evolutionary algorithm, implements a "curiosity instinct", favouring
controllers visiting many diverse sensori-motor states (sms). Further, the set
of sms discovered by an individual can be transmitted to its offspring, making
a cultural evolution mode possible. Cumulative entropy (computed from ancestors
and current individual visits to the sms) defines another self-driven fitness;
its optimization implements a "discovery instinct", as it favours controllers
visiting new or rare sensori-motor states. Empirical results on the benchmark
problems proposed by Lehman and Stanley (2008) comparatively demonstrate the
merits of the approach
Engineered polyketides: Synergy between protein and host level engineering
Metabolic engineering efforts toward rewiring metabolism of cells to produce new compounds often require the utilization of non-native enzymatic machinery that is capable of producing a broad range of chemical functionalities. Polyketides encompass one of the largest classes of chemically diverse natural products. With thousands of known polyketides, modular polyketide synthases (PKSs) share a particularly attractive biosynthetic logic for generating chemical diversity. The engineering of modular PKSs could open access to the deliberate production of both existing and novel compounds. In this review, we discuss PKS engineering efforts applied at both the protein and cellular level for the generation of a diverse range of chemical structures, and we examine future applications of PKSs in the production of medicines, fuels and other industrially relevant chemicals
Study of the auto-ignition phenomenon of PRFs under HCCI conditions in a RCEM by means of spectroscopy
An investigation of the effects of contour conditions and fuel properties on the auto-ignition and combustion
process under HCCI conditions is presented in this study. A parametric variation of initial temperature,
intake pressure, compression ratio, oxygen concentration and equivalence ratio has been carried out
for Primary Reference Fuels in a Rapid Compression Expansion Machine while applying spectroscopy. The
results have also been contrasted with natural chemiluminescence measurements. Additionally, the
experiments have been simulated in CHEMKIN and the results derived from the optical techniques have
been compared with the results from the chemical kinetics of the process, validating the chemical kinetic
mechanism and an additional sub-model of excited OH
. Two different scenarios can be seen according to
the results from the spectrograph. For very lean or very low-temperature combustions no peak of OH is
seen at 310 nm of wavelength, proving that the luminosity came from the CO continuum rather than
from the OH
. However, for more intense combustions (richer equivalence ratios, higher temperatures
or lower EGR rates) spectrography shows a clear peak of OH that has much longer time of life than
the corresponding to the CO continuum. The main chemical reaction that causes this two scenarios
has been identified as H þ HO2 ) 2OH. The increase of relevance of this reaction at high combustion temperatures
causes a higher OH accumulation, which leads to a brighter OH emission. Finally, for low temperature
combustions the CO continuum out-shines the OH radiation so the light emitted by this radical
cannot be detected by means of natural chemiluminescence.
201The authors would like to thank different members of the LAV team of the ETH-Zurich for their contribution to this work. The authors are grateful to the Universitat Politecnica de Valencia for financing the Ph.D. studies of W. Vera-Tudela (FPI SP1 grant 30/05/2012) and his stay at ETH-Zurich (grant 30/12/2014). Finally, the authors would like to thank the Spanish Ministry of Education for financing the Ph.D. studies of Dario Lopez-Pintor (grant FPU13/02329) and his stay at ETH-Zurich (grant EST14/00626).Desantes Fernández, JM.; García Oliver, JM.; Vera-Tudela-Fajardo, WM.; López Pintor, D.; Schneider, B.; Boulouchos, K. (2016). Study of the auto-ignition phenomenon of PRFs under HCCI conditions in a RCEM by means of spectroscopy. Applied Energy. 179:389-400. https://doi.org/10.1016/j.apenergy.2016.06.134S38940017
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