Repetitive rates of harp seal underwater vocalizations

1987 ◽  
Vol 65 (8) ◽  
pp. 2119-2120 ◽  
Author(s):  
J. M. Terhune ◽  
G. MacGowan ◽  
L. Underhill ◽  
K. Ronald
Keyword(s):  
Harp Seal ◽  
Level Control ◽  
Sampling Area ◽  
Significant Relationships ◽  
Phoca Groenlandica ◽  
Breeding Herd ◽  
Sound Pulses ◽  
Effective Sampling Area ◽  
Automatic Level

Underwater recordings of harp seal (Phoca groenlandica) vocalizations, obtained within the breeding herd during March, were examined with respect to calling rate and repetition of calls. Vocalizations typically overlapped one another. Calling rates ranged from 32 to 88 calls/min. Repetition rates averaged between 1.9 and 4.7 sound pulses/call (maximum repetition 24 times). Approximately 30% of the calls were not repeated and 40% were repeated twice. We found no significant relationships between calling rates and repetition rates. There were no variations in these factors throughout the day or month. An automatic level control on the recorder and the overlapping of the calls may have compromised the counts by altering the effective sampling area. The use of vocalization indexes in association with population estimations may be possible only when calls do not overlap.

Cytochrome P450-mediated enzyme activities and polychlorinated biphenyl accumulation in harp seal (Phoca groenlandica)

1999 ◽  
Vol 48 (1) ◽  
pp. 59-72 ◽  
Author(s):  
J Wolkers ◽  
I.C Burkow ◽  
M Monshouwer ◽  
C Lydersen ◽  
S Dahle ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Enzyme Activities ◽  
Polychlorinated Biphenyl ◽  
Harp Seal ◽  
Phoca Groenlandica

Automatic Control of Molten Metal Flow for Improving Casting Performance

2011 ◽  
Vol 693 ◽  
pp. 179-184
Author(s):  
Thomas Jarlsmark ◽  
Jan Strömbeck ◽  
Mikael Terner ◽  
Jerry Wilkins
Keyword(s):  
Molten Metal ◽  
Metal Flow ◽  
Casting Process ◽  
Direct Chill ◽  
Level Control ◽  
Level Measurement ◽  
Cost Efficient ◽  
Molten Metal Flow ◽  
Automatic Level ◽  
Rolling Ingot

The ways to gain better quality and higher casting performance is an urgent topic among aluminium producers today. This issue is also often on the agenda at conferences like this and the subjects and technologies to achieve this varies. Controlling the molten metal flow by maintaining predefined levels or level patterns is one of many powerful tools to reach this goal. Precimeter Control specializes in applications for non-ferrous molten metal level measurement and molten metal flow control. By integration, or retrofitting, any new or existing casting line can easily be automatically controlled and gain improved casting performance in a cost efficient way. This paper will focus on the main benefits from automatic level control and how some plants have achieved improvements in their casting process of DC (Direct Chill) slab (or rolling ingot) casting after implementing such technology.

Gastroliths in the harp seal Phoca Groenlandica

1995 ◽  
Vol 14 (3) ◽  
pp. 335-338
Author(s):  
Erling Sverre Nordøy
Keyword(s):  
Harp Seal ◽  
Phoca Groenlandica

scholarly journals Error in the Sampling Area of an Optical Disdrometer: Consequences in Computing Rain Variables

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
R. Fraile ◽  
A. Castro ◽  
M. Fernández-Raga ◽  
C. Palencia ◽  
A. I. Calvo
Keyword(s):  
Rainfall Intensity ◽  
Rain Event ◽  
Rain Intensity ◽  
Sampling Area ◽  
The Real ◽  
Efficient Sampling ◽  
Real Value ◽  
Effective Sampling Area ◽  
Reflectivity Factor

The aim of this study is to improve the estimation of the characteristic uncertainties of optic disdrometers in an attempt to calculate the efficient sampling area according to the size of the drop and to study how this influences the computation of other parameters, taking into account that the real sampling area is always smaller than the nominal area. For large raindrops (a little over 6 mm), the effective sampling area may be half the area indicated by the manufacturer. The error committed in the sampling area is propagated to all the variables depending on this surface, such as the rain intensity and the reflectivity factor. Both variables tend to underestimate the real value if the sampling area is not corrected. For example, the rainfall intensity errors may be up to 50% for large drops, those slightly larger than 6 mm. The same occurs with reflectivity values, which may be up to twice the reflectivity calculated using the uncorrected constant sampling area. TheZ-Rrelationships appear to have little dependence on the sampling area, because both variables depend on it the same way. These results were obtained by studying one particular rain event that occurred on April 16, 2006.

scholarly journals AUTOMATIC LEVEL CONTROL OF THE THICKNESS OF PRODUCT SLIVER

1960 ◽  
Vol 16 (4) ◽  
pp. 306-314
Author(s):  
Akira Aoki
Keyword(s):  
Level Control ◽  
Automatic Level

scholarly journals First independent feeding of harp seal (Phoca groenlandica) and hooded seal (Cystophora cristata) pups in the Greenland Sea

2000 ◽  
Vol 2 ◽  
pp. 29 ◽  
Author(s):  
Tore Haug ◽  
Kjell T Nilssen ◽  
Lotta Lindblom
Keyword(s):  
Interspecific Competition ◽  
Niche Overlap ◽  
Harp Seal ◽  
Minor Importance ◽  
Greenland Sea ◽  
The West ◽  
Hooded Seal ◽  
Cystophora Cristata ◽  
Phoca Groenlandica

Data were collected from harp seal (Phoca groenlandica) and hooded seal (Cystophora cristata) pups belonging to the Greenland Sea (or "West Ice") stocks in 1995-1997. Pups of both species were observed to feed independently shortly after weaning, and their first food was almost exclusively crustaceans. Parathemisto sp., particularly P. libellula, dominated the diet of both the harp and the hooded seal pups, but the diet also contained sympagic amphipods of the genus Gammarus. Krill (Thysanoessa sp.) was of minor importance as food for seal pups in 1995, but occurred more frequentlyin the diet of both species in 1996 and 1997. Considerable niche overlap may suggest some interspecific competition between harp and hooded seal pups in the West Ice.

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