Experimental Approach to the Hydraulics of Vertical Slot Fishways

The paper presents the hydraulic experimental results from different types of fish ladders heaving pools and baffles with submerged orifice or vertical slot. The goal of the experiments is to develop a database of velocities and power densities for each type of fish ladder with the baffles in different arrangements, for different lengths of the pools. So, based on the fish ladder type, the hydraulic characteristic database and the experimental laboratory model size provided by this study, one can improve the design of a fish ladder. The laboratory experimental model is designed with respect to Froude similarity criterion.

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Experimental Determination of the Effective Resolution Limit in Thick Specimens at High Voltages

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100116942 ◽

1975 ◽

Vol 33 ◽

pp. 664-665

Author(s):

Mircea Fotino

Keyword(s):

Experimental Approach ◽

Chromatic Aberration ◽

Resolving Power ◽

Biological Research ◽

Specimen Thickness ◽

Resolution Limit ◽

High Voltage Electron Microscopy ◽

Voltage Electron ◽

Resolution Level

The use of thick specimens (0.5 μm to 5.0 μm or more) is one of the most resourceful applications of high-voltage electron microscopy in biological research. However, the energy loss experienced by the electron beam in the specimen results in chromatic aberration and thus in a deterioration of the effective resolving power. This sets a limit to the maximum usable specimen thickness when investigating structures requiring a certain resolution level.An experimental approach is here described in which the deterioration of the resolving power as a function of specimen thickness is determined. In a manner similar to the Rayleigh criterion in which two image points are considered resolved at the resolution limit when their profiles overlap such that the minimum of one coincides with the maximum of the other, the resolution attainable in thick sections can be measured by the distance from minimum to maximum (or, equivalently, from 10% to 90% maximum) of the broadened profile of a well-defined step-like object placed on the specimen.

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Malfunctional Reorganization in the Developing Limbo-Prefrontal System in Animals: Implications for Human Psychoses?

Zeitschrift für Neuropsychologie ◽

10.1024//1016-264x.12.1.8 ◽

2001 ◽

Vol 12 (1) ◽

pp. 8-14

Author(s):

Gertraud Teuchert-Noodt ◽

Ralf R. Dawirs

Keyword(s):

Prefrontal Cortex ◽

Mental Disorders ◽

Dentate Gyrus ◽

Cognitive Functions ◽

Experimental Approach ◽

Regulatory Mechanisms ◽

Hippocampal Dentate Gyrus ◽

Non Invasive ◽

Invasive Method ◽

Activity Dependent

Abstract: Neuroplasticity research in connection with mental disorders has recently bridged the gap between basic neurobiology and applied neuropsychology. A non-invasive method in the gerbil (Meriones unguiculus) - the restricted versus enriched breading and the systemically applied single methamphetamine dose - offers an experimental approach to investigate psychoses. Acts of intervening affirm an activity dependent malfunctional reorganization in the prefrontal cortex and in the hippocampal dentate gyrus and reveal the dopamine position as being critical for the disruption of interactions between the areas concerned. From the extent of plasticity effects the probability and risk of psycho-cognitive development may be derived. Advance may be expected from insights into regulatory mechanisms of neurogenesis in the hippocampal dentate gyrus which is obviously to meet the necessary requirements to promote psycho-cognitive functions/malfunctions via the limbo-prefrontal circuit.

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