The role of fortified eyedrop antibiotic therapy in Pseudomonas aeruginosa corneal infection – a case report

Pseudomonas aeruginosa is a gram-negative bacterium and a leading cause of corneal ulcers. In the eye, extracellular enzymes may lead to keratitis, ulcer, endophthalmitis, rapid corneal destruction, and perforation leading to a quick loss of vision and necessity for urgent vitrectomy, amniotic membrane transplantation, or eye evisceration if no other therapy showed to be useful

The Field Theory of Collective Cherenkov Radiation Associated with Electron Beams

Classical Cherenkov radiation is a celebrated physics phenomenon of electromagnetic (EM) radiation stimulated by an electric charge moving with constant velocity in a three dimensional dielectric medium. Cherenkov radiation has a wide spectrum and a particular distribution in space similar to the Mach cone created by a supersonic source. It is also characterized by the energy transfer from the charge's kinetic energy to the EM radiation. In the case of an electron beam passing through the middle of a an EM waveguide, the radiation is manifested as collective Cherenkov radiation. In this case the electron beam can be viewed as a one-dimensional non-neutral plasma whereas the waveguide can be viewed as a slow wave structure (SWS). This collective radiation occurs in particular in traveling wave tubes (TWTs), and it features the energy transfer from the electron beam to the EM radiation in the waveguide. Based on a Lagrangian field theory, we develop a convincing argument that the collective Cherenkov effect in TWTs is, in fact, a convective instability, that is, amplification. We also derive, for the first time, expressions identifying low- and high-frequency cutoffs for amplification in TWT

Communicating with microwave-propelled sails

We describe a communication channel for a microwave-propelled sail, a novel concept for a deep-space scientific probe. We suggest techniques to recover the great loss introduced by the large distances, and we have conducted various simulations to understand the effects on the performance of the system. Possible disruption in the channel by high-energy solar flares, which increase the error in the estimation of the received signal, is accounted for. We developed the simulation for a full communication system on an additive white Gaussian noise (AWGN) channel, including the random-time solar-flare disturbance. We show that turbo codes can be exploited that perform very well at low SNRs and have high coding gain

Toward “smart tubes” using iterative learning control

In the paper, we present our progress toward designing a “smart” high-peak power microwave (HPM) tube. We use iterative learning control (ILC) methodologies in order to control a repetitively pulsed high-power backward-wave oscillator (BWO). The learning-control algorithm is used to drive the error between the actual output and its desired value to zero. The desired output may be a given power level, a given frequency, or a combination of both. The learning-control methodology is then verified in simulation. This methodology is applicable to a wide variety of HPM sources

Deterrence in Space

The recent increase in space activity brought space security considerations more to the forefront. Asthe chances of conflict in space are growing, scientific research aims at finding the possibly mosteffective tools to avoid or to win conflicts in this new domain.However, equipment deployed in space, in case it is destroyed, is hard to replace and due to thegenerated debris field, it can also endanger the capabilities of the attacker. Therefore, many expertsconsider deterrence as one of the most effective methods and try to adjust it for the space domain.However, there is a fundamental difference between the Western and the Russian or Chinese conceptsof this strategy. For the latter, coercion is an acceptable and logical part of deterrence

Studies of relativistic backward-wave oscillator operation in the cross-excitation regime

We first reported the operation of a relativistic backward-wave oscillator (BWO) in the so-called cross-excitation regime in 1998. This instability, whose general properties were predicted earlier through numerical studies, resulted from the use of a particularly shallow rippled-wall waveguide [slow wave structure (SWS)] that was installed in an experiment to diagnose pulse shortening in a long-pulse electron beam-driven high-power microwave (HPM) source. This SWS was necessary to accommodate laser interferometry measurements along the SWS during the course of microwave generation. Since those early experiments, we have studied this regime in greater detail using two different SWS lengths. We have invoked time-frequency analysis, the smoothed-pseudo Wigner-Ville distribution in particular, to interpret the heterodyned signals of the radiated power measurements. These recent results are consistent with earlier theoretical predictions for the onset and voltage scaling for this instability. This paper presents data for a relativistic BWO operating in the single-frequency regime for two axial modes, operating in the cross-excitation regime, and discusses the interpretation of the data, as well as the methodology used for its analysis. Although operation in the cross-excitation regime is typically avoided due to its poorer efficiency, it may prove useful for future HPM effects studies

Impact of meteorological variables on water quality parameters of a reservoir and ecological filtration system

Recently, special attention has been given to low-cost technologies for water treatment, with the aim of serving remote communities and thus enabling everyone to have access to drinking water and basic sanitation. In that context, the ecological filter is an alternative for treating water for human consumption. Some studies show that climate change and meteorological parameters can influence the water quality of water bodies and the water supply system. However, most of the papers deal with model projections and therefore do not show real situations. The aim of this study was to determine the impact of meteorological variables (e.g. atmospheric pressure, evaporation, wind speed, radiation, precipitation) on the physico-chemical and biological parameters (e.g. turbidity, apparent colour, pH, total coliforms, Escherichia coli) of Lobo reservoir water treated by 22 ecological filters during a period of 4 months. Statistically significant correlations were found between the water from the Lobo reservoir and the weather variables, and between the water quality parameters of the 22 ecological filters and the average weather variables. The results from the statistical analysis indicate that climatic variations may influence treatment performance