The Ames-Lockheed orbiter processing scheduling system

A general purpose scheduling system and its application to Space Shuttle Orbiter Processing at the Kennedy Space Center (KSC) are described. Orbiter processing entails all the inspection, testing, repair, and maintenance necessary to prepare the Shuttle for launch and takes place within the Orbiter Processing Facility (OPF) at KSC, the Vehicle Assembly Building (VAB), and on the launch pad. The problems are extremely combinatoric in that there are thousands of tasks, resources, and other temporal considerations that must be coordinated. Researchers are building a scheduling tool that they hope will be an integral part of automating the planning and scheduling process at KSC. The scheduling engine is domain independent and is also being applied to Space Shuttle cargo processing problems as well as wind tunnel scheduling problems

The Effect of a Changing Marriage Age on Marriage Continuity

Marriage stability has a wide range of determinants, such as education, marital history, and demographic characteristics. Age at marriage, however, has repeatedly been cited as one of the most important influences. Since the 1950s, divorce rates and the mean age at marriage for both men and women have seen a great deal of change. Past studies suggest that an early age at marriage is associated with a higher risk of divorce. Studies also propose that this relationship only holds up to a certain point. Changes to marriage age and divorce rates can have unforeseen interactions with cohabitation, fertility, educational attainment, and labor force participation. This research examines the significance of the relationship between the changing age at marriage and the changing rates of divorce. The data come from the American Community Survey from 2008 to 2017. A multivariate regression approach is implemented to estimate the probability of divorce within the past year for a given age at marriage. The analysis concludes that age at marriage does have a statistically significant effect on the probability of divorce. Older age at marriage is associated with an increase in the probability that an individual was divorced within the past year

Acoustic and Perceptual Characteristics of Prosody in Autism Spectrum Disorder: The Impact of Language, Motor Speech, and Auditory Processing

Autism Spectrum Disorder (ASD) is a lifelong neurodevelopmental condition that affects an individual’s social communication, social interaction, and behavior (American Psychological Association, 2013). A striking feature that distinguishes some individuals with autism from their peers without autism is “atypical” prosody. A between-group study was conducted to investigate prosody, speech motor control, auditory processing of pitch, and trained listener ratings of prosodic “naturalness” among adolescents with ASD (n=17) compared to TD controls (n=17) matched for age, gender and language. The specific aims of this study were to: (1) determine if individuals with ASD have significant acoustic-perceptual differences in their receptive and expressive prosody; (2) identify the interrelationship between prosody and language, motor speech, and pitch processing abilities; and (3) investigate if there is an association between group membership (ASD vs. TD) and trained listener ratings of overall “naturalness” (natural versus unnatural) of the speakers’ speech. The findings of this study support that some individuals with autism perform with significantly less accuracy on receptive and expressive prosody tasks and had significantly longer duration of utterances in comparison to TD controls. There was a significant positive relationship between receptive vocabulary and expressive prosody in the ASD group, supporting the “Theoretical Interaction Model”, while expressive vocabulary and speech motor control did not explain variability in expressive prosody above and beyond receptive vocabulary

Factors affecting phagocytosis and killing by neutrophils in urine

A raised neutrophil count in infected urine is a well recognised occurrence. However, many aspects of phagocytosis and killing by PMN in urine are poorly understood. To investigate PMN function a simple, rapid and efficient isolation method using differential centrifugation was developed. Lysing PMN in water at pH 11 at 37° C made it possible to assess killing more accurately. The method of opsonisation proved to be a major determinant for intracellular killing. E.coli exposed to nutrients in serum or urine for 30 min, prior to being phagocytosed, developed resistance to phagolysosome killing. The same strains opsonised simultaneously on exposure to the PMN were rapidly killed. This acquired resistance correlated with the growth phase. Phagocytosis of E. coli and S.saprophyticus was efficient in urine over a wide pH range (6 to 8) and occurred between 200 to 700 mOsm. PMN bactericidal activity was more sensitive, being the first function to be lost, but was at least 90% of control values between pH 6.5 to 7 at 485 mOsm and still active at 200 mOsm. Bacterial metabolites in overnight cultures of E. coli in urine affected killing by PMN to a greater extent than phagocytosis. This was not due to endotoxin. PMN phagocytosis and killing could take place in urines passed by volunteers during the afternoon, but not in early morning specimens. This was due to adverse conditions (pH and osmolality) in the latter. Water loading or ingestion of 4 gm sodium citrate provided conditions in the urine that were more favourable to phagocytosis and killing by PMN. In 20 freshly voided infected urines, adverse conditions of pH and osmolality prevented the majority of PMN (60%) phagocytosing efficiently. This was despite opsonins (mainly IgG) being present in 17, and most PMN being viable and able to phagocytose when removed from the urines. Bacteria-associated factors were of minor importance. Thus, raising the pH and reducing the osmolality of infected urine should allow natural defence mechanisms to eliminate infecting organisms more efficiently

Paper Session II-B - Space Shuttle Processing: A Case Study in Artificial Intelligence

Scheduling the ground processing functions of the Space Shuttle is an inherently difficult task. Most automated scheduling tools are oriented towards manufacturing problems which are very different from shuttle processing. The distinguishing factors between shuttle processing and manufacturing are: 1. Shuttle processing requires much unplanned to be added to the schedule while manufacturing process plans are typically determined well in advance. 2. Manufacturing activities are significantly more predictable than shuttle repair activities in terms of resource needs and durations. 3. Shuttle processing is fundamentally more complex than typical manufacturing concerns. 4. Shuttle processing requires reasoning about orbiter configuration as well as tasks and resources. To address these discrepancies, we have developed a new scheduling system that adopts Artificial Intelligence techniques. This paper describes the unique capabilities of this scheduling system as well as some preliminary results of the system using the shuttle data

Procedures for periodizing history: determining eras in the histories of Britain, France, Germany and Italy

Die Autoren entwickeln anhand konkreter Untersuchungen Vorschläge zum Problem der Periodisierung historischer Zeitabschnitte. Die theoretischen und methodischen Implikationen dieses Problems werden im Rahmen der Untersuchung des Wachstums der staatlichen Ausgaben für Erziehung, Gesundheit, Wohlfahrt und soziale Sicherung in den Ländern Großbritannien, Frankreich, Deutschland und Italien von 1870 bis 1965 dargestellt. Dieser Gegenstandsbereich wurde ausgewählt, weil sich an den Wandlungen in diesem Sektor auch die gesellschaftlichen Wandlungen ablesen lassen. Die Darstellung der Untersuchung umfaßt neben konkreten Ergebnissen die Analyse der methodischen und theoretischen Probleme, insbesondere die Behandlung der Daten und die alternativen Möglichkeiten der Periodisierung anhand einer Variable und mittels multipler Zeitläufe. Die Untersuchung ergibt, daß die traditionelle Chronologie nur in Einzelfällen zur Periodisierung ausreicht. (BG

Age-Dependent Effects Of Chronic GABAA Receptor Blockade In Barrel Cortex

GABAA receptor binding is transiently increased in rat whisker barrels during the second postnatal week, at a time when neurons in the developing rat cortex are vulnerable to excitotoxic effects. To test whether these GABAA receptors might serve to protect neurons from excessive excitatory input, polymer implants containing the GABAA receptor antagonist bicuculline were placed over barrel cortex for a 4-day period in young (postnatal days 8 - 12) and adult rats. In the cortex of young, but not adult rats, the chronic blockade of GABAA receptors resulted in substantial tissue loss and neuron loss. The greater loss of neurons in young rats supports the hypothesis that a high density of GABAA receptors protects neurons from excessive excitatory input during a sensitive period in development