Age-related response of male melon fliesDacus cucurbitae (Diptera: Tephritidae) to cue-lure

Laboratory-reared and wild adults of the melon fly,Dacus cucurbitae Coquillett, were tested for response to cue-lure at various ages. Virgin laboratory (4, 6, 8, 10, 12, and 14 days old) and wild (10, 12, 14, 16, 18, 20, and 22 days old) flies were released into outdoor field cages and trapped from 0800 until 1600 hr. Response of males to cue-lure increased with age and corresponded with sexual maturity for each strain. Females of both strains were relatively nonresponsive to cue-lure. Failure to eradicate in past male annihilation programs againstD. cucurbitae may be explained in part by the fact that only older males, which may have already mated with gravid females, respond to cue-lure.     

Environment as a first class abstraction in multiagent systems

The current practice in multiagent systems typically associates the environment with resources that are external to agents and their communication infrastructure. Advanced uses of the environment include infrastructures for indirect coordination, such as digital pheromones, or support for governed interaction in electronic institutions. Yet, in general, the notion of environment is not well defined. Functionalities of the environment are often dealt with implicitly or in an ad hoc manner. This is not only poor engineering practice, it also hinders engineers to exploit the full potential of the environment in multiagent systems. In this paper, we put forward the environment as an explicit part of multiagent systems.We give a definition stating that the environment in a multiagent system is a first-class abstraction with dual roles: (1) the environment provides the surrounding conditions for agents to exist, which implies that the environment is an essential part of every multiagent system, and (2) the environment provides an exploitable design abstraction for building multiagent system applications. We discuss the responsibilities of such an environment in multiagent systems and we present a reference model for the environment that can serve as a basis for environment engineering. To illustrate the power of the environment as a design abstraction, we show how the environment is successfully exploited in a real world application. Considering the environment as a first-class abstraction in multiagent systems opens up new horizons for research and development in multiagent systems.     

An analysis of lighting energy savings and switching frequency for a daylit corridor under various indoor design illuminance levels

Visual comfort and electric lighting energy issues are essential criteria to justify daylighting schemes. The evaluation of energy efficiency due to daylight linked lighting control systems is best demonstrated by case studies. This paper presents field measurements on daylighting for a fully air-conditioned daylit corridor. Artificial lighting load, brightness of the fluorescent luminaires, daylight availability for various switching illuminance levels were systematically recorded and analyzed. The general features and characteristics of the findings including the number of switching operations and electric-lighting energy savings are presented and discussed. Daylighting theories, using cumulative frequency distribution of outdoor illuminance and regression models based on brightness of light output, outdoor illuminance and electric light power to estimate daylight-linked lighting control savings, have been developed and assessed. It has been found that data from both approaches show reasonably good agreements with measured results. The findings from this study provide some operational and energy information, which would be useful and applicable to other interior spaces with similar architectural designs.     

Multiplicative Operator Splittings in Nonlinear Diffusion: From Spatial Splitting to Multiple Timesteps

Operator splitting is a powerful concept used in many diversed fields of applied mathematics for the design of effective numerical schemes. Following the success of the additive operator splitting (AOS) in performing an efficient nonlinear diffusion filtering on digital images, we analyze the possibility of using multiplicative operator splittings to process images from different perspectives.We start by examining the potential of using fractional step methods to design a multiplicative operator splitting as an alternative to AOS schemes. By means of a Strang splitting, we attempt to use numerical schemes that are known to be more accurate in linear diffusion processes and apply them on images. Initially we implement the Crank-Nicolson and DuFort-Frankel schemes to diffuse noisy signals in one dimension and devise a simple extrapolation that enables the Crank-Nicolson to be used with high accuracy on these signals. We then combine the Crank-Nicolson in 1D with various multiplicative operator splittings to process images. Based on these ideas we obtain some interesting results. However, from the practical standpoint, due to the computational expenses associated with these schemes and the questionable benefits in applying them to perform nonlinear diffusion filtering when using long timesteps, we conclude that AOS schemes are simple and efficient compared to these alternatives.We then examine the potential utility of using multiple timestep methods combined with AOS schemes, as means to expedite the diffusion process. These methods were developed for molecular dynamics applications and are used efficiently in biomolecular simulations. The idea is to split the forces exerted on atoms into different classes according to their behavior in time, and assign longer timesteps to nonlocal, slowly-varying forces such as the Coulomb and van der Waals interactions, whereas the local forces like bond and angle are treated with smaller timesteps. Multiple timestep integrators can be derived from the Trotter factorization, a decomposition that bears a strong resemblance to a Strang splitting. Both formulations decompose the time propagator into trilateral products to construct multiplicative operator splittings which are second order in time, with the possibility of extending the factorization to higher order expansions. While a Strang splitting is a decomposition across spatial dimensions, where each dimension is subsequently treated with a fractional step, the multiple timestep method is a decomposition across scales. Thus, multiple timestep methods are a realization of the multiplicative operator splitting idea. For certain nonlinear diffusion coefficients with favorable properties, we show that a simple multiple timestep method can improve the diffusion process.     

Chosen plaintext attack on a cryptosystem with discretized skew tent map

An encryption system with discretized skew tent map has been proposed recently by N. Masuda . However, there is a fundamental weakness with this chaotic cryptographic scheme. In this paper, a chosen plaintext attack requiring only two plaintexts is proposed. An improved version of this attack that narrows the key space need to be searched is also suggested. The test results demonstrate that this encryption cryptosystem is easily broken under the proposed chosen plaintext attack.     

Quadtree based colour quantisation image compression

A new colour quantisation and quadtree based image compression scheme is proposed. The features of the new scheme are that colour palette ordering and requantisation of the decoded image for palette-based monitor displays are not required. Thus, fast decoding and displaying can be achieved     

Interaction of soliton with sinusoidal wave packet

The interaction of a soliton of the Nonlinear Schrodinger Equation (NSE) with a weak sinusoidal wave packet is treated analytically. The second-order soliton solution containing the original soliton and a perturbing soliton is expanded to first order in the amplitude of the perturbating soliton. From this expansion, one obtains the associate function of Gordon (1992) and a continuous change of position and phase of the perturbed soliton. One finds that the soliton experiences a second-order change of velocity under the influence of the perturbation. This result is then used to derive the displacement due to a wave packet of general shape, which is also confirmed by computer simulation     

An antinociceptive effect of the intraperitoneal injection of nifedipine in rats, measured by tail-flick test

The tail-flick (TF) technique was used to assess the antinociceptive properties of nifedipine (NIF) given intraperitoneally (i.p.). First, the most suitable intensity of the noxious stimulus (temperature of the bulb) has been ascertained and used in the main study. Male Sprague-Dawley rats received NIF, dissolved in dimethyl sulfoxide (DMSO) at the doses of 0.0, 0.5, 2, 5, 10 and 15 mg/kg, or control with no injection. For the main study, the noxious stimulus was limited to 15 sec (cut-off time) and TF latencies were recorded up to 120 min. The antinociceptive response was expressed as the area under the curve for each rat and analyzed by one-way ANOVA. The antinociceptive response to the lower doses of NIF (0.5 and 2 mg/kg) did not differ from control (no injection) and DMSO alone. Significance was found at 5, 10 and 15 mg NIF with no difference among the doses. However, there was an increasing tendency of the mean values from 0.5 to 15 mg NIF resulting in a positive correlation. The correlation coefficient was 0.32483 (p = 0.015) and regression equation Y = (19.37) x dose + 1320. Our data suggest that spinal mechanisms are involved in NIF-induced antinociception.     

Tripartite hemolysin BL from Bacillus cereus. Hemolytic analysis of component interactions and a model for its characteristic paradoxical zone phenomenon

This study describes the use of the microdialysis technique to elucidate specific properties of the circadian pacemaking system in the hypothalamus, by measurement of melatonin production in the pineal gland. Melatonin has appeared to be a reliable marker of the pacemaker activity, which is influenced by the light/dark cycle. A phase shift in the light/dark cycle was applied to perturb the rhythm generating system. An 8-h phase advance resulted in the disappearance of melatonin production over two days, with basal levels comparable to normal daytime levels. In the subsequent return of rhythmic melatonin production, new clock characteristics could be revealed, due to the high time-resolution measurements of microdialysis. While half of the animals still did not show any rhythmicity, the other half of the animals regained rhythmicity with entrained onset of melatonin production, while the offset was variable and not stably entrained to lights on. Ten days after the shift, the system had completely recovered and all animals regained normal rhythmicity, in phase with the new light/dark cycle. The results are interpreted in terms of the two-oscillator model, with one oscillator reacting with a phase advance and the other with a phase delay to adapt to the phase shift.     

Gain-enhanced compact broadband microstrip antenna

With the loading of a high-permittivity superstrate layer and a 1 Ω chip resistor, a compact rectangular microstrip antenna with enhanced gain and wider bandwidth can be implemented. With the antenna size reduced to be ~6% that of a conventional patch antenna, the proposed structure can have an operating bandwidth of more than six times that of a conventional patch antenna, with an almost equal antenna gain level. Details of the experimental results are presented and discussed