Project for the analysis of technology transfer Annual report, 1969

Technology utilization of NASA programs and other research and development programs in Federal Government - project analysis results of technology transfe

Radiocarbon and blue optically stimulated luminescence chronologies of the Oitavos consolidated dune (Western Portugal)

The dune of Oitavos, the underlying paleosol, and Helix sp. gastropod shells found within the paleosol were dated using a combination of radiocarbon and blue optically stimulated luminescence (OSL). The organic component of the paleosol produced a significantly older age (~20,000 cal BP) than the OSL age measurement (~15,000 yr), while 14C age measurements on the inorganic component and the gastropods produced ages of ~35,000 yr and ~34,000 yr, respectively. Rare-earth element analyses provide evidence that the gastropods incorporate geological carbonate, making them an unreliable indicator of the age of the paleosol. We propose that the 14C age of the small organic component of the paleosol is also likely to be unreliable due to incorporation of residual material. The OSL age measurement of the upper paleosol (~15,000 yr) is consistent with the age for the base of the dune (~14,500 yr). The younger OSL age for the top of the dune (~12,000 yr) suggests that it was built up by at least 2 sand pulses or that there was a remobilization of material at the top during its evolution, prior to consolidation

Scalable design of tailored soft pulses for coherent control

We present a scalable scheme to design optimized soft pulses and pulse sequences for coherent control of interacting quantum many-body systems. The scheme is based on the cluster expansion and the time dependent perturbation theory implemented numerically. This approach offers a dramatic advantage in numerical efficiency, and it is also more convenient than the commonly used Magnus expansion, especially when dealing with higher order terms. We illustrate the scheme by designing 2nd-order pi-pulses and a 6th-order 8-pulse refocusing sequence for a chain of qubits with nearest-neighbor couplings. We also discuss the performance of soft-pulse refocusing sequences in suppressing decoherence due to low-frequency environment.Comment: 4 pages, 2 tables. (modified first table, references added, minor text changes

Paranoid thinking, cognitive bias and dangerous neighbourhoods: implications for perception of threat and expectation of victimisation

Background: Paranoid thinking is prevalent in the non-clinical population and cognitive mechanisms of heuristic reasoning and jumping to conclusions bias contributes to its formation and maintenance. Aims: This study investigated the degree to which paranoia, perceived environmental risk, heuristic reasoning and jumping to conclusions bias (measured with the beads task) contribute to misinterpretation of neutral stimuli, and whether this informed judgements regarding vulnerability to threat and crime. It is also investigated whether impulsiveness is a confounding factor on the beads task. Methods: Two hundred participants were recruited using a snowball-sampling method for a quantitative cross-sectional study. Participants reported demographic information, three psychometric questionnaires and two experimental tasks via an online paradigm hosted by the Bristol Online Survey tool. Results: Participants with high paranoia scores perceived their environment to be more dangerous than those with low scores. Participants with high paranoia scores also overestimated threat in neutral stimuli and had high expectations of future victimisation. Jumping to conclusions on the beads task did not predict fear of crime outcomes, but was predicted by impulsivity. Conclusion: Participants who demonstrated paranoid thinking were more likely to reside in perceived dangerous neighbourhoods and overestimate threat. While this could indicate a paranoid heuristic, it is a potentially rational response to prior experiences of crime and victimisation. Implications and suggestions for future research are discussed

Identifying the magnetotail lobes with Cluster magnetometer data

We describe a novel method for identifying times when a spacecraft is in Earth’s magnetotail lobes solely using magnetometer data. We propose that lobe intervals can be well identified as times when the magnetic field is strong and relatively invariant, defined using thresholds in the magnitude of BX and the standard deviation σ of the magnetic field magnitude. Using data from the Cluster spacecraft at downtail distances greater than 8 RE during 2001–2009, we find that thresholds of 30 nT and 3.5 nT, respectively, optimize agreement with a previous, independently derived lobe identification method that used both magnetic and plasma data over the same interval. Specifically, our method has a moderately high accuracy (66%) and a low probability of false detection (11%) in comparison to the other method. Furthermore, our method identifies the lobe on many other occasions when the previous method was unable to make any identification and yields longer continuous intervals in the lobe than the previous method, with intervals at the 90th percentile being triple the length. Our method also allows for analyses of the lobes outside the time span of the previous method

Distance, dissimilarity index, and network community structure

We address the question of finding the community structure of a complex network. In an earlier effort [H. Zhou, {\em Phys. Rev. E} (2003)], the concept of network random walking is introduced and a distance measure defined. Here we calculate, based on this distance measure, the dissimilarity index between nearest-neighboring vertices of a network and design an algorithm to partition these vertices into communities that are hierarchically organized. Each community is characterized by an upper and a lower dissimilarity threshold. The algorithm is applied to several artificial and real-world networks, and excellent results are obtained. In the case of artificially generated random modular networks, this method outperforms the algorithm based on the concept of edge betweenness centrality. For yeast's protein-protein interaction network, we are able to identify many clusters that have well defined biological functions.Comment: 10 pages, 7 figures, REVTeX4 forma

Structure of the SMC - Stellar component distribution from 2MASS data

The spatial distribution of the SMC stellar component is investigated from 2MASS data. The morphology of the different age populations is presented. The center of the distribution is calculated and compared with previous estimations. The rotation of the stellar content and possible consequence of dark matter presence are discussed. The different stellar populations are identified through a CMD diagram of the 2MASS data. Isopleth contour maps are produced in every case, to reveal the spatial distribution. The derived density profiles are discussed. The older stellar population follows an exponential profile at projected diameters of about 5 kpc (~5 deg) for the major axis and ~4 kpc for the minor axis, centred at RA: 0h:51min, Dec: -73deg 7' (J2000.0). The centre coordinates are found the same for all the different age population maps and are in good accordance with the kinematical centre of the SMC. However they are found considerably different from the coordinates of the centre of the gas distribution. The fact that the older population found on an exponential disk, gives evidence that the stellar content is rotating, with a possible consequence of dark matter presence. The strong interactions between the MCs and the MilkyWay might explain the difference in the distributions of the stellar and gas components. The lack in the observed velocity element, that implies absence of rotation, and contradicts with the consequences of exponential profile of the stellar component, may also be a result of the gravitational interactions.Comment: 7 Pages, 6 figures, accepted for publication in A&

Wideband Electrically Controlled Vernier Frequency Tunable Terahertz Quantum Cascade Laser

Frequency tuning in terahertz frequency quantum cascade lasers is challenging because of low thermal and current tuning coefficients. Moreover, photonic designs like Vernier selection based sampled gratings, used in telecom lasers to tune emission frequency, are unsuitable due to the long terahertz wavelengths and will require impractically long cavities (>15 mm). Here, we report the first wideband frequency tuning from a monolithic device exploiting Vernier selection rules using a coupled-cavity laser with a defect engineered photonic lattice. A precisely positioned defect lattice allows us to engineer the free spectral range and finesse of one of the cavities, similar to a sampled grating but using shorter cavity lengths (<4 mm). A coupled-cavity was used to tune the emission frequency. We achieve frequency tuning over 209 GHz, including mode hop-free continuous tuning of ∼6–21 GHz across six frequency bands, controlled through Stark shift, cavity-pulling, localized Joule heating, and thermal effects

Pressure Training for Performance Domains: A Meta-Analysis.

Studies have tested pressure training (PT) interventions in which performers practice physical or technical skills under simulated psychological pressure, but research has not yet synthesized the results of these studies. This meta-analysis assessed the magnitude of PT’s effect on performance in sport and other high-pressure domains (e.g., law enforcement). A secondary purpose was to investigate how domain, dose, experience, and the type of task moderated the effectiveness of interventions. A study was included if it was peer-reviewed, conducted a PT intervention for sport or another high-pressure domain, and quantitatively compared a PT group with a control group on posttests under pressure. In all, 14 studies in sport (k = 10) and law enforcement (k = 4) were included. Participants (n = 394) were novices, semiprofessional athletes, elite athletes, and police officers. After removal of an outlier, the mean effect was medium (g = 0.67, 95% confidence interval [0.43, 1.12]) with low heterogeneity (I2 = 17.1%). Subgroup analysis did not indicate clear moderators of performance but did reinforce that PT can benefit both novice and experienced participants on open and closed tasks across different domains. The results suggest coaches and instructors should create pressurized training environments rather than relying on greater amounts of training to help performers adjust to pressure. Future research should develop practical pressure manipulations, conduct retention tests, and measure performance in competitive or real-life scenarios