Evaluation of a computer-generated perspective tunnel display for flight path following

The display was evaluated by monitoring pilot performance in a fixed base simulator with the vehicle dynamics of a CH-47 tandem rotor helicopter. Superposition of the predicted future vehicle position on the tunnel image was also investigated to determine whether, and to what extent, it contributes to better system performance (the best predicted future vehicle position was sought). Three types of simulator experiments were conducted: following a desired trajectory in the presence of disturbances; entering the trajectory from a random position, outside the trajectory; detecting and correcting failures in automatic flight. The tunnel display with superimposed predictor/director symbols was shown to be a very successful combination, which outperformed the other two displays in all three experiments. A prediction time of 4 to 7 sec. was found to optimize trajectory tracking for the given vehicle dynamics and flight condition. Pilot acceptance of the tunnel plus predictor/director display was found to be favorable and the time the pilot needed for familiarization with the display was found to be relatively short

Recent experiences and emerging cooperation schemes on TA and education: an insight into cases in Portugal and Germany

At the beginning of the 21st century there are new expectations and challenges towards Technology Assessment (TA). Among these there is a new awareness on TA issues in education, in particular at universities. While TA was mainly an activity at extra-universitarian research institutions for a long time now there are new developments and initiative towards integrating TA issues in university courses. We will first give an insight into the international development. Secondly we will focus on the "TA and education" landscape in Germany and Portugal in more detail, followed by a description of new and emerging forms of cooperation between Portugal and Germany in this field which might serve as a model or an example for further cooperation between other partners

PAC-Bayes Un-Expected Bernstein Inequality

We present a new PAC-Bayesian generalization bound. Standard bounds contain a $\sqrt{L_n \cdot \operatorname{KL}/n}$ complexity term which dominates unless $L_n$, the empirical error of the learning algorithm's randomized predictions, vanishes. We manage to replace $L_n$ by a term which vanishes in many more situations, essentially whenever the employed learning algorithm is sufficiently stable on the dataset at hand. Our new bound consistently beats state-of-the-art bounds both on a toy example and on UCI datasets (with large enough $n$). Theoretically, unlike existing bounds, our new bound can be expected to converge to $0$ faster whenever a Bernstein/Tsybakov condition holds, thus connecting PAC-Bayesian generalization and excess risk bounds --- for the latter it has long been known that faster convergence can be obtained under Bernstein conditions. Our main technical tool is a new concentration inequality which is like Bernstein's but with $X^2$ taken outside its expectation

Suppression of biodynamic interference in head-tracked teleoperation

The utility of helmet-tracked sights to provide pointing commands for teleoperation of cameras, lasers, or antennas in aircraft is degraded by the presence of uncommanded, involuntary heat motion, referred to as biodynamic interference. This interference limits the achievable precision required in pointing tasks. The noise contributions due to biodynamic interference consists of an additive component which is correlated with aircraft vibration and an uncorrelated, nonadditive component, referred to as remnant. An experimental simulation study is described which investigated the improvements achievable in pointing and tracking precision using dynamic display shifting in the helmet-mounted display. The experiment was conducted in a six degree of freedom motion base simulator with an emulated helmet-mounted display. Highly experienced pilot subjects performed precision head-pointing tasks while manually flying a visual flight-path tracking task. Four schemes using adaptive and low-pass filtering of the head motion were evaluated to determine their effects on task performance and pilot workload in the presence of whole-body vibration characteristic of helicopter flight. The results indicate that, for tracking tasks involving continuously moving targets, improvements of up to 70 percent can be achieved in percent on-target dwelling time and of up to 35 percent in rms tracking error, with the adaptive plus low-pass filter configuration. The results with the same filter configuration for the task of capturing randomly-positioned, stationary targets show an increase of up to 340 percent in the number of targets captured and an improvement of up to 24 percent in the average capture time. The adaptive plus low-pass filter combination was considered to exhibit the best overall display dynamics by each of the subjects

Spin-Current Relaxation Time in Spin-Polarized Heisenberg Paramagnets

We study the spatial Fourier transform of the spin correlation function G_q(t) in paramagnetic quantum crystals by direct simulation of a 1d lattice of atoms interacting via a nearest-neighbor Heisenberg exchange Hamiltonian. Since it is not practical to diagonalize the s=1/2 exchange Hamiltonian for a lattice which is of sufficient size to study long-wavelength (hydrodynamic) fluctuations, we instead study the s -> infinity limit and treat each spin as a vector with a classical equation of motion. The simulations give a detailed picture of the correlation function G_q(t) and its time derivatives. At high polarization, there seems to be a hierarchy of frequency scales: the local exchange frequency, a wavelength-independent relaxation rate 1/tau that vanishes at large polarization P ->1, and a wavelength-dependent spin-wave frequency proportional to q^2. This suggests a form for the correlation function which modifies the spin diffusion coefficients obtained in a moments calculation by Cowan and Mullin, who used a standard Gaussian ansatz for the second derivative of the correlation function.Comment: 6 pages, 3 figure

The Current and Evolving Landscape of First-Line Treatments for Advanced Renal Cell Carcinoma

Agents targeting the vascular endothelial growth factor (VEGF) and its receptors (VEGFRs), as well as the mammalian target of rapamycin (mTOR) and immune checkpoint receptor programmed death 1 (PD-1) signaling pathway have improved clinical outcomes for patients with advanced renal cell carcinoma (RCC). The VEGFR tyrosine kinase inhibitors (TKIs) pazopanib and sunitinib are FDA-approved first-line treatment options for advanced RCC; however, other treatment options in this setting are available, including the recently approved combination of nivolumab (anti-PD-1) and ipilimumab (anti-cytotoxic T-lymphocyte-associated protein-4 [CTLA-4]) for patients with intermediate or poor risk. Unfortunately, treatment guideline recommendations provide little guidance to aid first-line treatment choice. In addition, several ongoing randomized phase III trials of investigational first-line regimens may complicate the RCC treatment paradigm if these agents gain approval. This article reviews clinical trial and real-world evidence for currently approved and investigational first-line treatment regimens for advanced RCC and provides clinical evidence to aid first-line treatment selection. Implications for Practice: Vascular endothelial growth factor receptor tyrosine kinase inhibitors are approved by the U.S. Food and Drug Administration as first-line treatment options for advanced renal cell carcinoma; however, the treatment paradigm is rapidly evolving. The combination of nivolumab plus ipilimumab was recently approved for intermediate- and poor-risk patients, and other combination strategies and novel first-line agents will likely be introduced soon

Lunnyu soils in the Lake Victoria basin of Uganda: Link to toposequence and soil type

We compared the physico-chemical characteristics of Lunnyu soils using soil type and slope position in order to explain their variability in the Lake Victoria basin of Uganda. Lunnyu patches located on four different soil types (chromic lixisol, mollic gleysols and plinthic ferralsols) were selected. At each patch, the slope was divided into shoulder, back-slope and foot-slope. Five locations along the contour of each landscape position and at distance of 20 to 30 m were located and soil samples taken at two depths (0 to 20 cm and 20 to 40 cm). The soils were analyzed for pH, available P, texture, and exchangeable bases. Lunnyu patches on chromic lixisol and mollic gleysols had higher pH, P, sand, clay and silt compared to those on plinthic ferralsols and petrifferic lixisol. Neither of the soil properties was influenced by landscape position. Soil pH, Ca, Mg, and K were higher in topsoil compared to subsoil. Neither slope position nor the type of lunnyu has showed consistent differences in all the soil properties. Results suggest a pedological explanation in which pH and texture could influence occurrence of the lunnyu soils. We recommend further studies of the pedological properties of the soils and other trace elements that this study has not investigated.Key words: Lunnyu soil, toposequence, soil type, Uganda

Pathological regional blood flow in opiate-dependent patients during withdrawal: A HMPAO-SPECT study

The aims of the present study were to investigate regional cerebral blood flow (rCBF) in heroin-dependent patients during withdrawal and to assess the relation between these changes and duration of heroin consumption and withdrawal data. The rCBF was measured using brain SPECT with Tc-99m-HMPAO in 16 heroin-dependent patients during heroin withdrawal. Thirteen patients received levomethadone at the time of the SPECT scans. The images were analyzed both visually and quantitatively, a total of 21 hypoperfused brain regions were observed in 11 of the 16 patients. The temporal lobes were the most affected area, hypoperfusions of the right and left temporal lobe were observed in 5 and 5 patients, respectively. Three of the patients had a hypoperfusion of the right frontal lobe, 2 patients showed perfusion defects in the left frontal lobe, right parietal lobe and left parietal lobe. The results of the quantitative assessments of the rCBF were consistent with the results of the qualitative findings. The stepwise regression analysis showed a significant positive correlation (r = 0.54) between the dose of levomethadone at the time of the SPECT scan and the rCBF of the right parietal lobe. Other significant correlations between clinical data and rCBF were not found. The present results suggest brain perfusion abnormalities during heroin withdrawal in heroin-dependent patients, which are not due to the conditions of withdrawal