Longitudinal changes in size and sorting of stream-bed material in four English rivers

Experiments were conducted to assess ways in which an imposed sediment load can affect the formation and final nature of an armoured bed. A flume loaded with a quartz aggregate of known composition was subjected to various sediment-laden flows of water to produce armoured beds. Characteristic parameters of the armoured beds were then compared.In general, it was found that the final armoured bed can be significantly altered by an imposed sediment load. As the size of the input sediment increased, the amount of bed material that was eroded, the resulting particle size of the bed, and the total roughness of the bed all decreased. The formation of bed forms was very important in this process. The trends observed in these experimental tests indicate that the presence or absence of upstream sediment sources has a direct influence on the resulting armoured layer.

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Entrainment and transport of coarse stream bed material in a fluviokarst watershed, south-central Missouri: a tracer particle study

10.32469/10355/8080 ◽

2010 ◽

Author(s):

Nathan R. Rossman

Keyword(s):

Tracer Particle ◽

South Central ◽

Bed Material ◽

Stream Bed

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Variations in grain-size distribution of suspended sediment in a glacial meltwater stream, Austre Okstindbreen, Norway

Journal of Glaciology ◽

10.3189/s0022143000042866 ◽

1991 ◽

Vol 37 (125) ◽

pp. 113-119

Author(s):

Erik Karlsen

Keyword(s):

Grain Size ◽

Size Distribution ◽

Suspended Sediment ◽

Grain Size Distribution ◽

Glacial Meltwater ◽

Hyperbolic Distribution ◽

Field Season ◽

Bed Material ◽

Grain Size Parameters ◽

Stream Bed

Abstract Thirty-nine samples of suspended sediment from the meltwater stream of Austre Okstindbreen, Norway, were analysed using both moments and parameters of the hyperbolic distribution. The samples turned out to be non-normally distributed. No direct correlation was found between discharge and grain-size distribution, but it is supposed that the hydraulic influence is hidden behind factors like composition of morainic or stream-bed material. Through comparison of the grain-size parameters from two periods in the field season, it was possible to distinguish between two sediment populations.

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Variations in grain-size distribution of suspended sediment in a glacial meltwater stream, Austre Okstindbreen, Norway

Journal of Glaciology ◽

10.1017/s0022143000042866 ◽

1991 ◽

Vol 37 (125) ◽

pp. 113-119 ◽

Cited By ~ 10

Author(s):

Erik Karlsen

Keyword(s):

Grain Size ◽

Size Distribution ◽

Suspended Sediment ◽

Grain Size Distribution ◽

Glacial Meltwater ◽

Hyperbolic Distribution ◽

Field Season ◽

Bed Material ◽

Grain Size Parameters ◽

Stream Bed

AbstractThirty-nine samples of suspended sediment from the meltwater stream of Austre Okstindbreen, Norway, were analysed using both moments and parameters of the hyperbolic distribution. The samples turned out to be non-normally distributed. No direct correlation was found between discharge and grain-size distribution, but it is supposed that the hydraulic influence is hidden behind factors like composition of morainic or stream-bed material. Through comparison of the grain-size parameters from two periods in the field season, it was possible to distinguish between two sediment populations.

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Longitudinal Changes in Individual BrainAGE in Healthy Aging, Mild Cognitive Impairment, and Alzheimer’s Disease

GeroPsych ◽

10.1024/1662-9647/a000074 ◽

2012 ◽

Vol 25 (4) ◽

pp. 235-245 ◽

Cited By ~ 64

Author(s):

Katja Franke ◽

Christian Gaser

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Healthy Aging ◽

Brain Aging ◽

Elderly Subjects ◽

Additional Increase ◽

Longitudinal Changes ◽

Novel Method ◽

The Brain

We recently proposed a novel method that aggregates the multidimensional aging pattern across the brain to a single value. This method proved to provide stable and reliable estimates of brain aging – even across different scanners. While investigating longitudinal changes in BrainAGE in about 400 elderly subjects, we discovered that patients with Alzheimer’s disease and subjects who had converted to AD within 3 years showed accelerated brain atrophy by +6 years at baseline. An additional increase in BrainAGE accumulated to a score of about +9 years during follow-up. Accelerated brain aging was related to prospective cognitive decline and disease severity. In conclusion, the BrainAGE framework indicates discrepancies in brain aging and could thus serve as an indicator for cognitive functioning in the future.

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