36,379 research outputs found
Simultaneous Estimation of Time Delays and Quasar Structure
We expand our Bayesian Monte Carlo method for analyzing the light curves of
gravitationally lensed quasars to simultaneously estimate time delays and
quasar structure including their mutual uncertainties. We apply the method to
HE1104-1805 and QJ0158-4325, two doubly-imaged quasars with microlensing and
intrinsic variability on comparable time scales. For HE1104-1805 the resulting
time delay of (Delta t_AB) = t_A - t_B = 162.2 -5.9/+6.3 days and accretion
disk size estimate of log(r_s/cm) = 15.7 -0.5/+0.4 at 0.2 micron in the rest
frame are consistent with earlier estimates but suggest that existing methods
for estimating time delays in the presence of microlensing underestimate the
uncertainties. We are unable to measure a time delay for QJ0158-4325, but the
accretion disk size is log(r_s/cm) = 14.9 +/- 0.3 at 0.3 micron in the rest
frame.Comment: 21 pages, 6 figures, submitted to Ap
Does Exposure and Receptivity to E-cigarette Advertisements Relate to E-cigarette and Conventional Cigarette Use Behaviors among Youth? Results from Wave 1 of the Population Assessment of Tobacco and Health Study
Background: E-cigarettes (EC) are the most commonly used tobacco product among youth. Additionally, youth EC users are progressing to smoking conventional cigarettes (CC). Although known to target youth, there are no current restrictions in the US on EC marketing, including advertising. The purpose of this study is to evaluate the relationship between EC advertisements and youth EC and CC use behaviors.
Methods: This study analyzed data from youth (12-17 years) aware of EC in Wave 1 (2013-2014) of the Population Assessment of Tobacco and Health (PATH) study (n=12,199). Weighted logistic regression models assessed whether exposure and receptivity to any of five randomized EC ads (two TV and three print) were associated with the outcomes of EC and CC behaviors of ever use, current (past 30 day) use, and susceptibility to future use. Additional analyses determined whether EC advertising exposure and EC and CC behaviors associations were moderated by EC advertising receptivity. All models were adjusted for sociodemographics, other combustible tobacco product use, and parent smoking.
Results: EC advertisement exposure was significantly associated to ever and current EC use as well as susceptibility to EC and CC (p
Conclusion: These findings demonstrate exposure to EC advertisements are particularly associated with EC use behaviors, but could play a role in future CC use as well. Youth who are receptive to EC advertisements appear particularly vulnerable. Further studies should focus on the role of receptivity to EC advertisements among youth in order to support regulatory policy targeting EC advertising
Rapid toxicity detection in water quality control utilizing automated multispecies biomonitoring for permanent space stations
The objective of this study was to evaluate proposed design characteristics and applications of automated biomonitoring devices for real-time toxicity detection in water quality control on-board permanent space stations. Simulated tests in downlinking transmissions of automated biomonitoring data to Earth-receiving stations were simulated using satellite data transmissions from remote Earth-based stations
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Teaching varies with task complexity in wild chimpanzees
Understanding social influences on how apes acquire tool behaviors can help us model the evolution of culture and technology in humans. Humans scaffold novice tool skills with diverse strategies, including the transfer of tools between individuals. Chimpanzees transfer tools, and this behavior meets criteria for teaching. However, it is unclear how task complexity relates to this form of helping. Here, we find differences between 2 wild chimpanzee populations in rate, probability, and types of tool transfer during termite gathering. Chimpanzees showed greater helping in the population where termite gathering is a more complex tool task. In wild chimpanzees, as in humans, regular and active provisioning of learning opportunities may be essential to the cultural transmission of complex skills.Cumulative culture is a transformative force in human evolution, but the social underpinnings of this capacity are debated. Identifying social influences on how chimpanzees acquire tool tasks of differing complexity may help illuminate the evolutionary origins of technology in our own lineage. Humans routinely transfer tools to novices to scaffold their skill development. While tool transfers occur in wild chimpanzees and fulfill criteria for teaching, it is unknown whether this form of helping varies between populations and across tasks. Applying standardized methods, we compared tool transfers during termite gathering by chimpanzees in the Goualougo Triangle, Republic of Congo, and in Gombe, Tanzania. At Goualougo, chimpanzees use multiple, different tool types sequentially, choose specific raw materials, and perform modifications that improve tool efficiency, which could make it challenging for novices to manufacture suitable tools. Termite gathering at Gombe involves a single tool type, fishing probes, which can be manufactured from various materials. Multiple measures indicated population differences in tool-transfer behavior. The rate of transfers and probability of transfer upon request were significantly higher at Goualougo, while resistance to transfers was significantly higher at Gombe. Active transfers of tools in which possessors moved to facilitate possession change upon request occurred only at Goualougo, where they were the most common transfer type. At Gombe, tool requests were typically refused. We suggest that these population differences in tool-transfer behavior may relate to task complexity and that active helping plays an enhanced role in the cultural transmission of complex technology in wild apes
Orbit transfer rocket engine integrated control and health monitoring system technology readiness assessment
The objectives of this task were to: (1) estimate the technology readiness of an integrated control and health monitoring (ICHM) system for the Aerojet 7500 lbF Orbit Transfer Vehicle engine preliminary design assuming space based operations; and (2) estimate the remaining cost to advance this technology to a NASA defined 'readiness level 6' by 1996 wherein the technology has been demonstrated with a system validation model in a simulated environment. The work was accomplished through the conduct of four subtasks. In subtask 1 the minimally required functions for the control and monitoring system was specified. The elements required to perform these functions were specified in Subtask 2. In Subtask 3, the technology readiness level of each element was assessed. Finally, in Subtask 4, the development cost and schedule requirements were estimated for bringing each element to 'readiness level 6'
Study of the factors influencing the composition of beef fat
TypescriptM.A. University of Missouri 1912The views upon the origin of body fat have undergone a number of changes in the last sixty or seventy years. These views have changed from the idea that body fat originated from the ingested fat to the later views that it originated from either protein or carbohydrate or a mixture of these. Each investigator has questioned the theories of the others until at the present time one is able to find a great deal of material in support of any one view. During the progress of the nutrition investigations begun at the Missouri Experiment Station in the spring of 1907, a considerable number of beef animals have been slaughtered. Most of these animals were secured at birth and were fed for definite conditions of development. This investigation was undertaken to study the composition of the fats from the different parts of the animal to show in what manner the composition may be influenced by age and condition.Includes bibliographical reference
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