Functional Sitting Skill Development, Sitting Posture and the Relationship to Object Permanence in Infants with Motor Delays

Functional Sitting Skill Development, Sitting Posture and the Relationship to Object Permanence in Infants with Motor Delays Early in development, infant movement allows exploration and manipulation of objects, which builds cognition. Object permanence, the ability to understand that objects exist when they cannot be seen, is a cognitive construct developed in infancy, and has been shown to relate to early motor development, specifically self-mobility. However, the development of sitting may also contribute to building cognition through object understanding. The purpose of this study was to investigate the relationship of functional sitting skill development, measured by a standardized clinical test (Gross Motor Function Measure [GMFM], sitting subscale) and sitting posture, measured by angular forward lean of the trunk in sitting. Sitting posture was measured by an iPad app, Angles Video Goniometer©. In this study, which is part of a larger early intervention study conducted in homes, 25 infants with severe motor disorders, mean age at baseline 10 months, were assessed for gains in object permanence, angle of trunk lean, and functional sitting between baseline and 3 months. A multiple linear regression was calculated to predict object permanence scores based on their change in GMFMsit scores and angle of trunk lean. A significant regression equation was found (F(2, 22)=9.63, p2 of .467. However, only GMFMsit was a significant predictor of object permanence scores (t=4.03, p=0.001). Infants who were able to achieve higher functional sitting skills were able to perform better on the cognitive measure regardless of “normal” posture. Infant improvements in sitting, even with adaptive postures, may impact the emergence of object permanence in young infants. This is important clinically because physical therapists often focus on alignment of posture in both early sitting and standing, at the expense of allowing functional adaptations that can drive cognitive advancement

Long-Term Object Permanence and Sitting in Infants with Motor Delays

This study investigated the development of Object Permanence (OP) in infants with varying levels of motor delays and the relationship between sitting skill development and OP skill over time. Infants (n = 37; baseline mean age = 12mos, 14dys), stratified into groups of mild, moderate, and significant motor delay, participated in a randomized controlled trial (Harbourne et al, 2018). Children were assessed at baseline, 1.5-mos, 3-mos, 6-mos and 12-mos. OP behaviors were coded on a 20-point ordinal scale using Datavyu software. Sitting skill was measured using the Gross Motor Function Measure-88, sitting dimension (GMFM-SD). A Kruskal-Wallis test with Bonferroni correction indicated significant differences between the 3 groups’ OP scores at all 5 assessments. Dunn’s post hoc test showed significant differences between the mild and significant and the moderate and significant groups for OP scores at each visit. Spearman’s rho statistic showed significant positive correlations between OP and GMFM-SD scores. Correlations of change scores for OP and GMFM-SD between baseline and 6-months, and between baseline and 12-months, revealed weak positive correlations for 6- and 12-months assessments, which suggests non-linear progressions of skills

The Relationship Between Focused Attention and Object Permanence in Infants with Motor Delays

Background: Focused attention (uninterrupted attention to task) and understanding of object permanence (knowledge that objects exist when not seen) are two constructs in infancy that build future cognitive skills. The relationship between the two in infants with delays is poorly understood. Purpose: The purpose of this study was to examine the relationship of early focused attention at the point of early sitting independence to object permanence skill one year later in infants with motor delays. Methods: 15 infants (aged 8-16 months) with motor delays were scored on an analog scale of 1-5 (5 = greatest focus) to indicate their level of global focused attention during two specific object permanence tasks, a switch task and a displacement task. All infants were enrolled in a larger trial aimed at improving motor development. Object permanence testing was conducted after 12 months. The scores were correlated using a graphing method. Results: Increased focused attention on the displacement task at 1.5 months correlated strongly to overall object permanence at 12 months (estimate R2=0.52). The correlation between focused attention during the switch task at 1.5 months and total object permanence at 12 months was low (R2=0.10). The stronger correlation of the displacement task likely occurs because the displacement task only requires observation of actions, whereas the switch task requires both memory of the hidden object and observation of actions. Conclusion: This study provides evidence that focused attention early in development contributes to building cognitive constructs like object permanence in infants with motor delays

Taxation Practices in an Ideal Economy

Taxation varies in degree depending on global location. Some economies practice socialistic policies, others practice capitalistic policies. However, no existing economy is entirely socialistic or entirely capitalistic. Each economy finds its own balance, which leads to its own level of equality and efficiency. Capitalistic societies are known for the efficient use of resources, and socialistic societies are known for ensuring, at least, a certain minimum standard of living for all people involved in the economy. An economist might suppose there exists a unique point on a taxation continuum which most effectively serves the members of most societies. It seems logical to conclude that an economy that is useful to a society should involve a balance of socialistic and capitalistic provisions. The research included in this article attempts to locate such a point on the taxation spectrum defined above.</p

Development, modeling and testing of thermal protection systems in small, slow-burning solid rocket motors

Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.Cataloged from PDF version of thesis.Includes bibliographical references (pages 59-60).Currently, a void exists in the development of small, unmanned aerial vehicles (UAVs) that can fly at speeds faster than 100 meters per second while maximizing endurance. Operating in such a regime requires the use of a slow-burning solid rocket motor. To achieve long burn times, an end-burning grain configuration is required in addition to a burn rate suppressant. Such a propulsion system presents unique thermal challenges due to the long exposure times and the close proximity of temperature sensitive vehicle components to the combustion reactions. This thesis presents the development of a thermal management system appropriate for small, slow burning solid rocket motors. Thermal protection is provided primarily by a thermally ablative liner with additional layers of fibrous insulation to protect the motor casing and avionics. Due to the complex nature of thermochemical ablation and scarcity of previous research in slow, end burning solid rockets, this problem is approached through both experimental and computational means. Experimental tests are performed on a full-scale model of an end-burning motor. Experimental results are used to validate a computational model of ablation. The ultimate goal is to provide an adequate amount of thermal insulation to protect the vehicle casing and avionics while maximizing propellant volume and hence endurance. Building such thermal management schemes requires innovative materials and machining methods to incorporate thermal protection in a tight space. This thesis adds to the greater body of knowledge of thermal protection design in slow-burning solid rockets, especially as it applies to a new class of small, fast UAVs.by Jonathan R. Spirnak.S.M