Utilization of SAGE aerosol profiles in the analysis of Mauna Loa stratospheric lidar data

A systematic approach to analyzing lidar data collected at NOAA's Mauna Loa Observatory (MLO) was developed which relies on parameters derived from SAGE satellite extinction profile measurements to verify boundary conditions applied to analysis. The approach also provides a means of assessing the uncertainties associated with the various inputs, so that the accuracy of the analysis of the MLO lidar data is available. The stratosphere during the 1980 to 1981 period was only mildly perturbed and could be easily represented by the SAMII/SAGE background aerosol model. The MLO lidar observations collected during this period provided stratospheric optical depths with uncertainties ranging between 15% and 25%. Uncertainties in the aerosol optical model contribute errors of 3% to 4% in the computed optical depths. Most of the optical depth uncertainty is associated with the calibration assumption in which no marked improvement can be expected

Productivity Growth in the 1990s: Technology, Utilization, or Adjustment?

Measured productivity growth increased substantially during the second half of the 1990s. This paper examines whether this increase owes to an increase in the rate of technological change or whether it can be explained by non-technological factors relating to factor utilization, factor accumulation, or returns to scale. It finds that the recent increase in productivity growth does appear to arise from an increase in technological change. Cyclical utilization raised measured productivity growth relative to technology growth in the first part of the expansion, but lowered it subsequently. Factor adjustment leads to a steady-state understatement of technology growth by measured productivity growth. The understatement was greater in the second half of the expansion than the first. Changes in the distribution of inputs across industries with different returns to scale lead to a modest understatement in the growth in technology. Although the increase technological change is most pronounced in durable manufacturing, technological change also increased outside of manufacturing.

Productivity growth in the 1990s: technology, utilization, or adjustment

Measured productivity growth increased substantially during the second half of the 1990s. This paper examines whether this increase owes to an increase in the rate of technological change or whether it can be explained by non-technological factors relating to factor utilization, factor accumulation, or returns to scale. It finds that the recent increase in productivity growth does appear to arise from an increase in technological change. Cyclical utilization raised measured productivity growth relative to technology growth in the first part of the expansion, but lowered it subsequently. Factor adjustment leads to a steady-state understatement of technology growth by measured productivity growth. The understatement was greater in the second half of the expansion than the first. Changes in the distribution of inputs across industries with different returns to scale lead to a modest understatement in the growth in technology. Although the increase technological change is most pronounced in durable manufacturing, technological change also increased outside of manufacturing.Productivity ; Technology ; Manufactures

Aircraft energy efficiency laminar flow control wing design study

An engineering design study was performed in which laminar flow control (LFC) was integrated into the wing of a commercial passenger transport aircraft. A baseline aircraft configuration was selected and the wing geometry was defined. The LFC system, with suction slots, ducting, and suction pumps was integrated with the wing structure. The use of standard aluminum technology and advanced superplastic formed diffusion bonded titanium technology was evaluated. The results of the design study show that the LFC system can be integrated with the wing structure to provide a structurally and aerodynamically efficient wing for a commercial transport aircraft

Social regulation of male reproductive plasticity in an African cichlid fish

Social interactions with the outcome of a position in a dominance hierarchy can have profound effects on reproductive behavior and physiology, requiring animals to integrate environmental information with their internal physiological state; but how is salient information from the animal\u27s dynamic social environment transformed into adaptive behavioral, physiological, and molecular-level changes? The African cichlid fish, Astatotilapia burtoni, is ideally suited to understand socially controlled reproductive plasticity because activity of the male reproductive (brainpituitary gonad) axis is tightly linked to social status. Males form hierarchies in which a small percentage of brightly colored dominant individuals have an active reproductive axis, defend territories, and spawn with females, while the remaining males are subordinate, drably colored, do not hold a territory, and have a suppressed reproductive system with minimal opportunities for spawning. These social phenotypes are plastic and quickly reversible, meaning that individual males may switch between dominant and subordinate status multiple times within a lifetime. Here, we review the rapid and remarkable plasticity that occurs along the entire reproductive axis when males rise in social rank, a transition that has important implications for the operational sex ratio of the population. When males rise in rank, transformations occur in the brain, pituitary, circulation, and testes over short time-scales (minutes to days). Changes are evident in overt behavior, as well as modifications at the physiological, cellular, and molecular levels that regulate reproductive capacity. Widespread changes triggered by a switch in rank highlight the significance of external social information in shaping internal physiology and reproductive competence. © The Author 2013. All rights reserved

Behavioral and physiological plasticity: Rapid changes during social ascent in an African cichlid fish

In many vertebrates, reproduction is regulated by social interactions in which dominant males control access to females and food. Subordinate males that displace dominant individuals must rapidly adopt behavioral and physiological traits of the higher rank to gain reproductive success. To understand the process of phenotypic plasticity during social ascent, we analyzed the temporal expression pattern of dominance behaviors and circulating androgen levels when socially-suppressed males of an African cichlid fish Astatotilapia burtoni ascended in status. These experiments tested a prediction of the \u27challenge hypothesis\u27 that, during periods of social instability, male androgen levels are higher than during socially stable times. We found that socially and reproductively suppressed males perform territorial and reproductive behaviors within minutes of an opportunity to ascend in status, and that animals switch from initial expression of territorial behaviors to more reproductive behaviors during territory establishment. Following this rapid response, social stability may be achieved within 1-3. days of social ascent. Consistent with predictions of the \u27challenge hypothesis\u27, circulating 11-ketotestosterone (11-KT) levels were elevated within 30. min following social opportunity, coincident with increased aggressive behavior. However, territorial behaviors and serum 11-KT levels were then dissociated by 72. h after social ascent, suggesting either rapid social stability and/or increased physiological potential for androgen production. This behavioral and physiological plasticity in male A. burtoni suggests that perception of social opportunity triggers a suite of quick changes to facilitate rapid transition towards reproductive success, and reveals important features of social ascent not previously recognized. © 2010 Elsevier Inc

Infants' developing competence in recognizing and understanding words in fluent speech

Again and again in research on early cognitive development, infants turn out to be smarter than we thought they were. The refinement of experimental tech-niques for reading infants ' minds has been extremely productive, enabling us to study developing capabilities which are not yet observable in spontaneous behavior. When the task demands are made simple enough, infants demonstrate implicit knowledge across diverse domains ranging from understanding of the physical world and numerical concepts to social cognition (see Wellman & Gelman 1998). In the domain of language understanding as well, such techniques have been used to reveal the early emergence of linguistic competence before it is evident in overt behavior, and many ingenious experiments have demonstrated the considerable speech processing savvy of infants in the first year. These studies show that certain perceptual skills essential for spoken language under-standing emerge gradually over the first year, often months before infants are able to display their linguistic knowledge through speech production (see Aslin, Jusczyk & Pisoni 1998). Our own recent research on word recognition by olde

Contextual chemosensory urine signaling in an African cichlid fish

Chemosensory signaling is crucial for communication in many fish species, but little is known about how signalers modulate chemical output in response to sensory information and social context. Here, we tested the hypothesis that dominant male African cichlid fish (Astatotilapia burtoni) use urine signals during social interactions, and demonstrate that this signaling depends on social context (reproductive; territorial) and on available sensory information (visual cues; full interaction). We injected males with dye to visualize urine pulses and exposed them to full sensory information or visual cues alone of four types: (1) dominant male; (2) gravid (reproductively receptive) females; (3) mouth-brooding (non-receptive) females; or (4) control (no fish). We found that males released urine sooner and increased their urination frequency when visually exposed to gravid females as compared with mouth-brooding females and or no-fish controls. While males could distinguish female reproductive states using visual cues alone, courtship behavior rates were ̃10-fold higher when they fully interacted with gravid females compared with receiving visual cues alone. Males also increased their urination and territorial behaviors when exposed to another male, suggesting that chemical signals may convey information on dominance status. These data support the hypothesis that dominant males use urine as a chemical signal and adjust the frequency of their urine output based on contextual information. © 2012. Published by The Company of Biologists Ltd

When half a word is enough: infants can recognize spoken words using partial phonetic information

Adults process speech incrementally, rapidly identifying spoken words on the basis of initial phonetic information sufficient to distinguish them from alternatives. In this study, infants in the second year also made use of word-initial information to understand fluent speech. The time course of comprehension was examined by tracking infants' eye movements as they looked at pictures in response to familiar spoken words, presented both as whole words in intact form and as partial words in which only the first 300 ms of the word was heard. In Experiment 1, 21-month-old infants (N = 32) recognized partial words as quickly and reliably as they recognized whole words; in Experiment 2, these findings were replicated with 18-month-old infants (N = 32). Combining the data from both experiments, efficiency in spoken word recognition was examined in relation to level of lexical development. Infants with more than 100 words in their productive vocabulary were more accurate in identifying familiar words than were infants with less than 60 words. Grouped by response speed, infants with faster mean reaction times were more accurate in word recognition and also had larger productive vocabularies than infants with slower response latencies. These results show that infants in the second year are capable of incremental speech processing even before entering the vocabulary spurt, and that lexical growth is associated with increased speed and efficiency in understanding spoken language