Cognitive Information Processing

Contains reports on one research project.National Institutes of Health (Grant 5 P01 GM14940-07

Long-term perturbations due to a disturbing body in elliptic inclined orbit

In the current study, a double-averaged analytical model including the action of the perturbing body's inclination is developed to study third-body perturbations. The disturbing function is expanded in the form of Legendre polynomials truncated up to the second-order term, and then is averaged over the periods of the spacecraft and the perturbing body. The efficiency of the double-averaged algorithm is verified with the full elliptic restricted three-body model. Comparisons with the previous study for a lunar satellite perturbed by Earth are presented to measure the effect of the perturbing body's inclination, and illustrate that the lunar obliquity with the value 6.68\degree is important for the mean motion of a lunar satellite. The application to the Mars-Sun system is shown to prove the validity of the double-averaged model. It can be seen that the algorithm is effective to predict the long-term behavior of a high-altitude Martian spacecraft perturbed by Sun. The double-averaged model presented in this paper is also applicable to other celestial systems.Comment: 28 pages, 6 figure

Reducing Racial and Gender Implicit Biases: The Effects of Multicultural Education on a Child’s Preferences and Occupational Aspirations

This project explored the effect of reducing implicit racial and gender bias and the impact on children’s occupational preferences and aspirations. Participants included fifty-two children aged three, four, and five years old from the Connecticut College Children’s Program in New London, Connecticut. The initial hypothesis theorized that children, regardless of race and gender, would have a preference towards White and male individuals as being “good or nice,” and for most occupational roles. The children would also have a prejudice against individuals of color as being “naughty or bad,” and for most occupational roles. The other hypothesis theorized that after children received multicultural occupational literature intervention, their implicit biases would decrease, especially for children of color, female children, and three year old children. The results of this study showed that the children who received multicultural occupational literature intervention reduced their negative implicit biases and caused them to increase their occupational preferences for themselves and others, in comparison to the children who did not receive the literature intervention. Ultimately, this study expresses the effect that early multicultural literature can have on positively impacting racial and gender attitudes in young children

Robust Capture and Transfer Trajectories for Planetary Satellite Orbiters

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77371/1/AIAA-13761-765.pd

GaAs spectrometer for planetary electron spectroscopy

Work towards producing a radiation-hard and high temperature tolerant direct detection electron spectrometer is reported. The motivation is to develop a low-mass, low-volume, low-power, multi-mission capable instrument for future space science missions. The resultant prototype electron spectrometer employed a GaAs p+-i-n+ mesa photodiode (10 µm i layer thickness; β00 μm diameter) and a custom-made charge-sensitive preamplifier. The GaAs detector was initially electrically characterized as a function of temperature. The detector-preamplifier assembly was then investigated for its utility in electron spectroscopy across the temperature range 100 °C to 20 °C using a laboratory 63Ni radioisotope - particle source (end point energy = 66 keV). Monte Carlo simulations using the computer program CASINO were conducted and showed that the spectrometer had a quantum detection efficiency which increased with increasing electron energy up to 70 keV; a quantum detection efficiency of 73 % was calculated. The accumulated 63Ni - particle spectra together with CASINO simulations of the detected spectra showed that the GaAs based spectrometer could be used for counting electrons and measuring the energy deposited per electron in the detector’s active region (i layer). The development of a GaAs electron spectrometer of this type may find use in future space missions to environments of intense radiation (such as at the surface of Europa for investigation of electron-driven radiolysis of ice) and high temperature (such as at Mercury, and comets passing close to the Sun)

Design of Science Orbits About Planetary Satellites: Application to Europa

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76381/1/AIAA-19464-587.pd

Sortilin Participates in Light-dependent Photoreceptor Degeneration in Vivo

Both proNGF and the neurotrophin receptor p75 (p75NTR) are known to regulate photoreceptor cell death caused by exposure of albino mice to intense illumination. ProNGF-induced apoptosis requires the participation of sortilin as a necessary p75NTR co-receptor, suggesting that sortilin may participate in the photoreceptor degeneration triggered by intense lighting. We report here that light-exposed albino mice showed sortilin, p75NTR, and proNGF expression in the outer nuclear layer, the retinal layer where photoreceptor cell bodies are located. In addition, cone progenitor-derived 661W cells subjected to intense illumination expressed sortilin and p75NTR and released proNGF into the culture medium. Pharmacological blockade of sortilin with either neurotensin or the “pro” domain of proNGF (pro-peptide) favored the survival of 661W cells subjected to intense light. In vivo, the pro-peptide attenuated retinal cell death in light-exposed albino mice. We propose that an auto/paracrine proapoptotic mechanism based on the interaction of proNGF with the receptor complex p75NTR/sortilin participates in intense light-dependent photoreceptor cell death. We therefore propose sortilin as a putative target for intervention in hereditary retinal dystrophies