A study of ignition pressure spiking in attitude control engines. Volume 1 - Evaluation of the use of catalytic surfaces to eliminate ignition pressure spiking Final report, 1 Jul. 1966 - 30 Apr. 1967

Effects of injector catalytic surfaces on ignition pressure spiking in Apollo command module engin

Loving-Kindness Meditation and Prosocial Construct Activation

Both Buddhist and psychological theory postulate that present actions will influence future perceptions, judgments, and behaviors in a concordant manner. While Buddhists explain these effects in the context of karmic theory, psychologists consider these effects of construct activation and chronic construct accessibility. The present study sought to apply social psychological theory to Buddhist meditation practice, specifically to examine if loving-kindness meditation (LKM) increases prosocial construct accessibility over time, as compared to mindfulness meditation. University students practiced either mindfulness meditation or LKM for eight weeks. Measures were administered at baseline and after the eight weeks of practice. Although results did not demonstrate changes in prosocial construct accessibility, all participants experienced increases in mindfulness, satisfaction with life, emotional reappraisal abilities, and emotion management. These effects were also accompanied decreases in illness symptoms over time. Analyses yielded mixed results for measures of wisdom. The current experiment failed to replicate some known effects of mindfulness meditation, such as increases in attentional control and decreases in depressive symptoms. Limitations of the study and future directions are discussed

A study of ignition pressure spiking in attitude control engines. Volume 2 - A comparison of nitrogen tetroxide/ monomethylhydrazine and hydrogen peroxide/ monomethylhydrazine ignition pressure spiking characteristics

Comparison, at simulated altitude, of nitrogen tetroxide/monomethylhydrazine and hydrogen peroxide/monomethylhydrazine ignition pressure spiking characteristic

Aging and Error Processing: Age Related Increase in the Variability of the Error-Negativity Is Not Accompanied by Increase in Response Variability

Background: Several studies report an amplitude reduction of the error negativity (Ne or ERN), an event-related potential occurring after erroneous responses, in older participants. In earlier studies it was shown that the Ne can be explained by a single independent component. In the present study we aimed to investigate whether the Ne reduction usually found in older subjects is due to an altered component structure, i.e., a true alteration in response monitoring in older subjects. Methodology/Principal Findings: Two age groups conducted two tasks with different stimulus response mappings and task difficulty. Both groups received fully balanced speed or accuracy instructions and an individually adapted deadline in both tasks. Event-related potentials, Independent Component analysis of EEG-data and between trial variability of the Ne were combined with analysis of error rates, coefficients of variation of RT-data and ex-Gaussian fittings to reaction times. The Ne was examined by means of ICA and PCA, yielding a prominent independent component on error trials, the Ne-IC. The Ne-IC was smaller in the older than the younger subjects for both speed and accuracy instructions. Also, the Ne-IC contributed to a much lesser extent to the Ne in older than in younger subjects. RT distribution parameters were not related to Ne/ERP-variability. Conclusions/Significance: The results show a genuine reduction as well as a different component structure of the Ne in older compared to young subjects. This reduction is not reflected in behaviour, apart from a general slowing of olde

Isotopic study of Raman active phonon modes in β-Ga2O3

Holding promising applications in power electronics, the ultra-wide band gap material gallium oxide has emerged as a vital alternative to materials like GaN and SiC. The detailed study of phonon modes in β-Ga2O3 provides insights into fundamental material properties such as crystal structure and orientation and can contribute to the identification of dopants and point defects. We investigate the Raman active phonon modes of β-Ga2O3 in two different oxygen isotope compositions (16O,18O) by experiment and theory: By carrying out polarized micro-Raman spectroscopy measurements on the (010) and (-201) planes, we determine the frequencies of all 15 Raman active phonons for both isotopologues. The measured frequencies are compared with the results of density functional perturbation theory (DFPT) calculations. In both cases, we observe a shift of Raman frequencies towards lower energies upon substitution of 16O with 18O. By quantifying the relative frequency shifts of the individual Raman modes, we identify the atomistic origin of all modes (Ga-Ga, Ga-O or O-O) and present the first experimental confirmation of the theoretically calculated energy contributions of O lattice sites to Raman modes. The DFPT results enable the identification of Raman modes that are dominated by the different, inequivalent O- or Ga-atoms of the unit cell. We find that oxygen substitution on the OII site leads to an elevated relative mode frequency shift compared to OI and OIII sites. This study presents a blueprint for the future identification of different point defects in Ga2O3 by Raman spectroscopy

Dopamine transporter (DAT1) and dopamine receptor D4 (DRD4) genotypes differentially impact on electrophysiological correlates of error processing

Peer reviewedPublisher PD

Response Monitoring in De Novo Patients with Parkinson's Disease

BACKGROUND: Parkinson's disease (PD) is accompanied by dysfunctions in a variety of cognitive processes. One of these is error processing, which depends upon phasic decreases of medial prefrontal dopaminergic activity. Until now, there is no study evaluating these processes in newly diagnosed, untreated patients with PD ("de novo PD"). METHODOLOGY/PRINCIPAL FINDINGS: Here we report large changes in performance monitoring processes using event-related potentials (ERPs) in de novo PD-patients. The results suggest that increases in medial frontal dopaminergic activity after an error (Ne) are decreased, relative to age-matched controls. In contrast, neurophysiological processes reflecting general motor response monitoring (Nc) are enhanced in de novo patients. CONCLUSIONS/SIGNIFICANCE: It may be hypothesized that the Nc-increase is at costs of dopaminergic activity after an error; on a functional level errors may not always be detected and correct responses sometimes be misinterpreted as errors. This pattern differs from studies examining patients with a longer history of PD and may reflect compensatory processes, frequently occurring in pre-manifest stages of PD. From a clinical point of view the clearly attenuated Ne in the de novo PD patients may prove a useful additional tool for the early diagnosis of basal ganglia dysfunction in PD

A Fast and Reliable Method for Simultaneous Waveform, Amplitude and Latency Estimation of Single-Trial EEG/MEG Data

The amplitude and latency of single-trial EEG/MEG signals may provide valuable information concerning human brain functioning. In this article we propose a new method to reliably estimate single-trial amplitude and latency of EEG/MEG signals. The advantages of the method are fourfold. First, no a-priori specified template function is required. Second, the method allows for multiple signals that may vary independently in amplitude and/or latency. Third, the method is less sensitive to noise as it models data with a parsimonious set of basis functions. Finally, the method is very fast since it is based on an iterative linear least squares algorithm. A simulation study shows that the method yields reliable estimates under different levels of latency variation and signal-to-noise ratioÕs. Furthermore, it shows that the existence of multiple signals can be correctly determined. An application to empirical data from a choice reaction time study indicates that the method describes these data accurately