Present state of knowledge of the upper atmosphere: An assessment report; processes that control ozone and other climatically important trace gases

The state of knowledge of the upper atmosphere was assessed as of January 1986. The physical, chemical, and radiative processes which control the spatial and temporal distribution of ozone in the atmosphere; the predicted magnitude of ozone perturbations and climate changes for a variety of trace gas scenarios; and the ozone and temperature data used to detect the presence or absence of a long term trend were discussed. This assessment report was written by a small group of NASA scientists, was peer reviewed, and is based primarily on the comprehensive international assessment document entitled Atmospheric Ozone 1985: Assessment of Our Understanding of the Processes Controlling Its Present Distribution and Change, to be published as the World Meteorological Organization Global Ozone Research and Monitoring Project Report No. 16

Fluid structure interaction of submerged metallic and composite plates subjected to low velocity impact loading

An instrumented low velocity impact rig has been used to acquire experimental data for impacts in air and underwater for both metallic and composite plates when subjected to a low velocity drop-weight impact with a 2kg steel impactor. Initial impact studies were conducted in air and then repeated for submersed conditions underwater. Experimental results are compared for all tests with numerical solutions and are found to be in good agreement. For underwater impact, the numerical model incorporates the use of a Eulerian formulation for the water with a coupled fluid-structure interaction algorithm. The effect of the water surrounding the target plates was found to reduce the peak accelerations and also reduce the overall impact duration when compared to the same impacts in air. X-Ray imagery of the composite plates also showed visibly reduced damage for the submersed test specimens. This research provides data on the impact response of metallic and composite materials, and validates numerical methodologies for use in future work on fluid-structure interactions which show strong potential for relevant industrial applications

Kinetic and photochemical data for atmospheric chemistry reactions of the nitrogen oxides

Data sheets for thermal and photochemical reactions of importance in the atmospheric chemistry of the nitrogen oxides are presented. For each reaction the available experimental data are summarized and critically evaluated, and a preferred value of the rate coefficient is given. The selection of the preferred value is discussed and an estimate of its accuracy is given. For the photochemical process, the data are summarized, and preferred for the photoabsorption cross section and primary quantum yields are given

Dopaminergic Modulation of Gap Junction Permeability Between Amacrine Cells in Mammalian Retina

In mammalian retina, the rod bipolar cells synapse on the AII amacrine cells, which are therefore the third-order neurons in the rod-signal pathway. The AII amacrine cells are connected by gap junctions, both to each other and to fourth-order, On-center cone bipolar cells. They also receive synaptic input from the dopaminergic amacrine cells, and in this study, we investigated whether dopamine modulates the permeability of the gap junctions between AII amacrine cells in the isolated rabbit retina. The small biotinylated tracer Neurobiotin was injected into nuclear yellow-labeled AII cells under direct microscopic control. The extent of tracer coupling to neighboring AII cells, 40-60 min after Neurobiotin injection (0.5 nA for 60 sec), provided a standard measure of the permeability of the homologous gap junctions. Under control conditions, individual All amacrine cells were coupled to 73 +/- 15 neighboring cells, and this was unaffected by changes in pH from 6.6 to 7.8. Exogenous dopamine significantly reduced the tracer coupling at concentrations as low as 10 nM (26 +/- 16 cells), with the eff ect increasing with dopamine concentration up to 10 muM (6 +/- 4 cells). The uncoupling effect of dopamine was both blocked by the selective D1 antagonist SCH-23390 (10 muM) and mimicked by the specific D1 agonist SKF-38393 (500 muM). Moreover, the All amacrine cells were also uncoupled when the retina was incubated in forskolin (60 muM) and isobutylmethylxanthine (200 muM). Taken together, these results indicated that the uncoupling was mediated by a D1-like receptor that stimulates cAMP production. Although the selective D1 antagonist on its own did not increase tracer coupling, suggesting that there was little release of endogenous dopamine in the superfused photo-bleached retina, veratridine-evoked release of endogenous transmitters did uncouple the AII amacrine cells, and this effect was blocked by the specific D1 antagonist

Landscape attributes governing local transmission of an endemic zoonosis: rabies virus in domestic dogs

Landscape heterogeneity plays an important role in disease spread and persistence, but quantifying landscape influences and their scale dependence is challenging. Studies have focused on how environmental features or global transport networks influence pathogen invasion and spread, but their influence on local transmission dynamics that underpin the persistence of endemic diseases remains unexplored. Bayesian phylogeographic frameworks that incorporate spatial heterogeneities are promising tools for analysing linked epidemiological, environmental and genetic data. Here, we extend these methodological approaches to decipher the relative contribu- tion and scale-dependent effects of landscape influences on the transmission of endemic rabies virus in Serengeti district, Tanzania (area ~4,900 km2). Utilizing detailed epidemiological data and 152 complete viral genomes collected between 2004 and 2013, we show that the localized presence of dogs but not their density is the most important determinant of diffusion, implying that culling will be ineffec- tive for rabies control. Rivers and roads acted as barriers and facilitators to viral spread, respectively, and vaccination impeded diffusion despite variable annual cov- erage. Notably, we found that landscape effects were scale-dependent: rivers were barriers and roads facilitators on larger scales, whereas the distribution of dogs was important for rabies dispersal across multiple scales. This nuanced understanding of the spatial processes that underpin rabies transmission can be exploited for targeted control at the scale where it will have the greatest impact. Moreover, this research demonstrates how current phylogeographic frameworks can be adapted to improve our understanding of endemic disease dynamics at different spatial scales

Time-Varying Sliding Mode Control for ABS Control of an Electric Car

Controller design for the Anti-Lock Braking System (ABS) of a wheeled vehicle is a challenging task because of the complex and nonlinear nature of the tyre-road interaction. An efficient ABS controller should be capable of maintaining the wheel slip at an optimal value, which is suitable for the particular road conditions experienced at a given instant in time, preventing the wheel from locking while braking. Many controller designs in the literature track either an optimal slip which is assumed constant or are not supported by experimental validation or simulation testing with higher order models. This paper first presents an ABS system based on a conventional Sliding Mode Control (SMC). The performance of this controller is tested on an experimental vehicle. The results are compared with simulation results obtained with both a quarter car model and a full-car model built in the Matlab/Simulink environment. The performance of this controller is improved by effective state estimation using a Sliding Mode Differentiator (SMD) where the results are benchmarked with an implementation using an Extended Kalman Filter (EKF). The paper then presents a controller based on Time-Varying Sliding Mode Control (TV-SMC) which tracks an optimal slip trajectory

Sexual and Relationship Violence Prevention and Response: What Drives the Commuter Campus Student Experience?

This exploratory study brings together two lines of inquiry on (a) college campus-based responses to sexual and intimate partner violence among students, and (b) the characteristics, experiences, and challenges unique to commuter students and commuter institutions of higher education. Using qualitative analysis of 14 in-depth interviews with campus personnel and focus groups with a total of 71 students on three commuter campuses in the Pacific Northwest, we offer a detailed description of the experiences and characteristics of commuter students as they pertain to sexual and relationship violence programming and prevention, the associated nature of commuter campus communities, and the resulting lack of visibility of the issue of sexual and relationship violence on commuter campuses. We conclude that creative, tailored approaches to prevention and response services on commuter campuses are needed to address the unique circumstances and challenges facing commuter campus students