Concrete Strength Required to Open to Traffic

The current empirical methods for determining traffic-opening criteria can be overly conservative causing unnecessary construction delays and user costs. The research described here recommends innovative mechanistic based procedures for monitoring concrete early age development and evaluating the effect of early traffic opening on long-term damage accumulation. The procedure utilizes recent developments in nondestructive testing to optimize traffic opening timing without jeopardizing pavement longevity. These tasks were achieved via extensive field and laboratory experiments allowing for the analysis of variables such as curing condition and loading type with respect to the effect of early loading of concrete. The results of these efforts culminated in the development of a program that analyzes the effect of design and opening time decisions on pavement damage. The deliverable can be utilized by transportation agencies to make more informed decisions

Disengagement of visual attention in infancy is associated with emerging autism in toddlerhood

Background: Early emerging characteristics of visual orienting have been associated with a wide range of typical and atypical developmental outcomes. In the current study, we examined the development of visual disengagement in infants at risk for autism. Methods: We measured the efficiency of disengaging from a central visual stimulus to orient to a peripheral one in a cohort of 104 infants with and without familial risk for autism by virtue of having an older sibling with autism. Results: At 7 months of age, disengagement was not robustly associated with later diagnostic outcomes. However, by 14 months, longer latencies to disengage in the subset of the risk group later diagnosed with autism was observed relative to other infants at risk and the low-risk control group. Moreover, between 7 months and 14 months, infants who were later diagnosed with autism at 36 months showed no consistent increases in the speed and flexibility of visual orienting. However, the latter developmental effect also characterized those infants who exhibited some form of developmental concerns (but not meeting criteria for autism) at 36 months. Conclusions: Infants who develop autism or other developmental concerns show atypicality in the development of visual attention skills from the first year of life

Study of the Impacts of Implements of Husbandry on Bridges Volume III: Appendices

The objectives of this study were to develop guidance for engineers on how implements of husbandry loads are resisted by traditional bridges, with a specific focus on bridges commonly found on the secondary road system; provide recommendations for accurately analyzing bridges for these loading effects; and make suggestions for the rating and posting of these bridges. To achieve the objectives, the distribution of live load and dynamic impact effects for different types of farm vehicles on three general bridge types\u2014steel-concrete, steel-timber, and timber-timber\u2014were investigated through load testing and analytical modeling. The types of vehicles studied included, but were not limited to, grain wagons/grain carts, manure tank wagons, agriculture fertilizer applicators, and tractors. Once the effects of these vehicles had been determined, a parametric study was carried out to develop live load distribution factor (LLDF) equations that account for the effect of husbandry vehicle loads. Similarly, recommendations for dynamic effects were also developed. The live load distribution factors and dynamic load allowances are covered in the first volume of the report. Finally, suggestions on the analysis, rating, and posting of bridges for husbandry implements were developed. Those suggestions are covered in the second volume of the report. This third volume of the report contains six appendices that include the 19 mini-reports for field tested and analytically modeled steel-concrete, steel-timber, and timber-timber bridges, the farm implement and bridge inventories for the project, and survey responses

Advancing Bridge Load Rating: State of Practice and Frameworks

693JJ319D000020 TO693JJ320F000170The U.S. has more than 600,000 bridges, making the distributed load rating and posting processes across the nation a significant effort that does and can benefit from improvements in efficiency. Bridge load rating, posting, and overweight permitting processes evolve due to the regulatory requirements regarding the frequency of inspections and relevant changes to bridges that necessitate re-rating them. These factors include changes to the dead load, strength of members, and any maintenance or rehabilitation work. As such, States are interested in modifying their procedures to implement technology and improved means and methods to reduce the time associated with load rating. Being able to load rate bridges efficiently and accurately is a necessity, particularly in the use case of permit load routing. Based on the extensive findings during the information collection processes for this project, frameworks for future bridge load rating, posting, and overweight permitting were developed to improve productivity, efficiency, and consistency by closing process gaps and through the application of newer technologies. The newer technologies include digital twin concepts; integrating various (new) data; creating, updating, and reusing models; integrating sensing data (bridge, traffic, weigh-in-motion); and better analysis methods. This work may help develop the state of practice

The development of face orienting mechanisms in infants at-risk for autism

A popular idea related to early brain development in autism is that a lack of attention to, or interest in, social stimuli early in life interferes with the emergence of social brain networks mediating the typical development of socio-communicative skills. Compelling as it is, this developmental account has proved difficult to verify empirically because autism is typically diagnosed in toddlerhood, after this process of brain specialization is well underway. Using a prospective study, we directly tested the integrity of social orienting mechanisms in infants at-risk for autism by virtue of having an older diagnosed sibling. Contrary to previous accounts, infants who later develop autism exhibit a clear orienting response to faces that are embedded within an array of distractors. Nevertheless, infants at-risk for autism as a group, and irrespective of their subsequent outcomes, had a greater tendency to select and sustain attention to faces. This pattern suggests that interactions among multiple social and attentional brain systems over the first two years give rise to variable pathways in infants at-risk

Early predictors of impaired social functioning in male rhesus macaques (Macaca mulatta)

Autism spectrum disorder (ASD) is characterized by social cognition impairments but its basic disease mechanisms remain poorly understood. Progress has been impeded by the absence of animal models that manifest behavioral phenotypes relevant to ASD. Rhesus monkeys are an ideal model organism to address this barrier to progress. Like humans, rhesus monkeys are highly social, possess complex social cognition abilities, and exhibit pronounced individual differences in social functioning. Moreover, we have previously shown that Low-Social (LS) vs. High-Social (HS) adult male monkeys exhibit lower social motivation and poorer social skills. It is not known, however, when these social deficits first emerge. The goals of this study were to test whether juvenile LS and HS monkeys differed as infants in their ability to process social information, and whether infant social abilities predicted later social classification (i.e., LS vs. HS), in order to facilitate earlier identification of monkeys at risk for poor social outcomes. Social classification was determined for N = 25 LS and N = 25 HS male monkeys that were 1–4 years of age. As part of a colony-wide assessment, these monkeys had previously undergone, as infants, tests of face recognition memory and the ability to respond appropriately to conspecific social signals. Monkeys later identified as LS vs. HS showed impairments in recognizing familiar vs. novel faces and in the species-typical adaptive ability to gaze avert to scenes of conspecific aggression. Additionally, multivariate logistic regression using infant social ability measures perfectly predicted later social classification of all N = 50 monkeys. These findings suggest that an early capacity to process important social information may account for differences in rhesus monkeys’ motivation and competence to establish and maintain social relationships later in life. Further development of this model will facilitate identification of novel biological targets for intervention to improve social outcomes in at-risk young monkeys

U.S. national security strategy in Southeast Asia: a reappraisal

The United States found itself at the end of the Cold War with a predominately military national security strategy that has been less relevant in coping with the residue of the bi-polar world. Furthermore, the general diffusion of power in the international system from military capability towards economic might highlights the need for a general reappraisal of U.S. interests, objectives, and strategy. This thesis begins with a definition of global U.S. national interests and then defines the specific objectives of the national strategy as applied to the Asia-Pacific region and Southeast Asia. In following chapters, it analyzes the security environment of Southeast Asia, the enduring and developing conflicts within the region and with external powers, as well as mechanisms for conflict resolution. Finally, it asks whether official U.S. strategy adequately promotes and protects the national interests of the United States. It concludes that the current U.S. national security strategy of 'engagement and enlargement' is flawed and must not confuse the national interests, such as the survival of the United States and its prosperity, or put international relationships at risk for the sake of national values, such as the promotion of democracy and human rights abroad.http://archive.org/details/usnationalsecuri1094531437U.S. Navy (U.S.N.) author

Use of Ultrasonic Acoustic Technology for Temporary Deterrence of Bats from Bridges

White-Nose Syndrome and increased disturbance of habitats used by bats for roosting and foraging has led to a growing concern about the bat population in the US in the last decade. Bridge repair and replacement projects are required to follow additional regulatory requirements to avoid and minimize impacts to bats when protected bat species are present on bridges. Some of these requirements (e.g., timing restrictions) are challenging to implement, given Minnesota’s short construction season. The objective of this project was to evaluate the feasibility and efficacy of deploying non-lethal ultrasonic acoustic devices in the field to temporarily deter bats from roosting on bridges ahead of construction or maintenance activities, while minimizing harm to bats and non-target species. The technology was evaluated at two test sites located in Minnesota, one short term and one long term, during the summer of 2019. The data from the field inspections indicate that acoustic deterrents appear to effectively work to temporarily deter bats from select abutments and present an option to temporarily deter bats at construction sites. This technology could be implemented by any transportation agency, but would require the development of an agency protocol, through collaboration of relevant offices

Individual Differences in Infant Visual Attention: Are Short Lookers Faster Processors or Feature Processors?

Individual differences in the duration of infants\u27 visual fixations are reliable and stable and have been linked to differential cognitive performance; short-looking infants typically perform better than long-looking infants. 4 experiments tested the possibility of whether short lookers\u27 superiority on perceptual-cognitive tasks is attributable to attention to the featural details of visual stimuli, or simply to differences in the speed or efficiency of visual processing. To do this, the performance of long- and short-looking 4-month-olds was examined on separate discrimination tasks that could be solved only by processing either featural or global information. The global task was easier than the featural task, but as the amount of time allotted for infants to solve either type of task was decreased, short lookers\u27 performance was superior to that of long lookers. These results thus lend support to a speed or efficiency of stimulus processing interpretation of infant fixation duration