Introduced species represent one of the most serious global threats to biodiversity. In this field-based study, we assessed behavioural responses of brood tending cichlid fish to an invasive predator of their offspring. This was achieved by comparing parental defence responses of the endangered arrow cichlid (Amphilophus zaliosus), a fish species endemic to the crater lake Apoyo in Nicaragua, t...

This paper presents the results of a series of hollow cylinder tests carried out to investigate the role of drainage conditions on the response of railway track foundation materials during cyclic loading. Three sand–clay mixes were tested. It was found that, below a certain cyclic shear stress threshold, and depending on the drainage conditions, changes in principal stress direction should not ...

BACKGROUND Approximately 30% of the U.S. population reports recurrent short sleep; however, perceived sleep need varies widely among individuals. Some "habitual short sleepers" routinely sleep 4-6 hr/night without self-reported adverse consequences. Identifying neural mechanisms underlying individual differences in perceived sleep-related dysfunction has important implications for understanding...

Previous studies have addressed railway turnouts (switches and crossings), but research on the performance of 1000 mm gauge is limited. At present, wooden sleeper structures are used at in Vietnam. However, these many disadvantages operation process. This paper evaluates new prestressed bearer (PSB) for turnouts, designed gauge, to overcome a sleeper. Test samples PSB were manufactured factory,...

The purpose of the following paper is to present author’s experimental field investigations a jointless railway track subjected generated imperfection and analysis response applied static loads. An optical measurement system, Pontos, was used for dynamic track’s deflections in 3D. allow us recommend direct application this system non-contact measurement, visualization simulated defects track, a...

Elastic elements such as rail pads, under sleeper pads and under ballast mats are railway components that allow for a reduction in track deterioration and vibrations. And they are furthermore commonly used to obtain an optimal vertical stiffness of the infrastructure. However, the use of elastomeric materials can increase construction costs and the consumption of raw materials. Thus, the utiliz...

Mandelic acid can serve as sole source of carbon and energy for the growth of certain strains of Pseudomonas fluorescens. Analysis of the enzymatic patterns of cells grown on various substrates (Stanier, 1947, 1948; Sleeper and Stanier, 1950) has led to formulation of the following sequence for the initial steps in its diimilation: Mandelic acid -b benzoylformic acid -. benzaldehyde -* benzoic ...

Study Objectives: Cortical hyperarousal, observed in insomnia individuals, could be influenced by sleep quality and objective sleep misperception. Usually, to be considered as a first night effect, a decrease in the quality of sleep during the first recording night in the laboratory is observed. The objectives of this study are to examine cortical arousal differences according to sleeper types ...

CONTEXT The deceleration phase of the throwing motion creates large distraction forces at the shoulder, which may result in posterior shoulder tightness and ensuing alterations in shoulder range of motion (ROM) and may result in an increased risk of shoulder injury. Researchers have hypothesized that various stretching options increase this motion, but few data on the effectiveness of treating ...