Life Histories of Hexagenia limbata and Ephemera simulans (Ephemeroptera) in Dauphin Lake, Manitoba

1987 ◽  
Vol 6 (4) ◽  
pp. 230-240 ◽  
Author(s):  
Brian A. Heise ◽  
John F. Flannagan ◽  
Terry D. Galloway
Keyword(s):  
Life Histories ◽  
Hexagenia Limbata

Production of Hexagenia limbata (Serville) and Ephemera simulans Walker (Ephemeroptera) in Dauphin Lake, Manitoba, with a Note on Weight Loss due to Preservatives

1988 ◽  
Vol 45 (5) ◽  
pp. 774-781 ◽  
Author(s):  
Brian A. Heise ◽  
John F. Flannagan ◽  
Terry D. Galloway
Keyword(s):  
Weight Loss ◽  
Life Histories ◽  
Instantaneous Growth ◽  
Size Frequency ◽  
Wet Weight ◽  
Growth Production ◽  
Length Changes ◽  
Sand And Gravel ◽  
Hexagenia Limbata ◽  
Growth Methods

Annual production and biomass of Hexagenia limbata (Serville) and Ephemera simulans Walker were estimated from samples taken from May through September of 1982 and 1983 in Dauphin Lake, Manitoba. The size–frequency estimates (± 2 SE) of production for H. limbata were 12.6 ± 2.68 g/m2 (wet weight) in, 1982 and 10.1 ± 2.10 g/m2 in 1983. Instantaneous growth production estimates were 9.51 and 9.76 g/m21982) and 9.49 and 8.55 g/m2 (1983) based on life history interpretations of four versus seven cohorts, respectively. Elucidation of complex life histories involving overlapping cohorts may not be necessary in order to make accurate production estimates for similar semivoltine populations. Annual [Formula: see text] ratios for H. limbata ranged from 1.68 to 2.38. Production estimates for E. simulans in 1983 were 9.02 ± 3.10 and 9.90 g/m2, using the size–frequency and instantaneous growth methods, respectively. Hexagenia limbata weight loss due to preservation in 10% formalin followed by 75% ethanol resulted in a production underestimate of 25%. Length changes of H. limbata in the same preservatives were not significant (p > 0.05). Hexagenia limbata was found at all stations having a silt/clay component. Ephemera simulans was found only on a matrix substrate of clay, silt, sand and gravel.

Life Histories of Patients With Chronic Ulcerative Colitis: A Review of 2,000 Cases

1950 ◽  
Vol 16 (1) ◽  
pp. 25-38 ◽  
Author(s):  
Wyman P. Sloan ◽  
F. Arnold Bargen ◽  
Robert P. Gage
Keyword(s):  
Ulcerative Colitis ◽  
Chronic Ulcerative Colitis ◽  
Life Histories

Power and politics in migration narrative methodology: Research with young Congolese migrants in Uganda

2009 ◽  
Vol 6 (2) ◽  
pp. 131-141 ◽  
Author(s):  
Christina Clark-Kazak
Keyword(s):  
Qualitative Research ◽  
Young People ◽  
Life Histories ◽  
Narrative Research ◽  
Power Dynamics ◽  
Methodological Issues ◽  
Personal Boundaries ◽  
Migration Narratives ◽  
Narrative Methodology

This paper explores the power dynamics inherent in qualitative research involving migration narratives. Drawing on the author’s experiences collecting life histories and constructing narratives of Congolese young people in Uganda, this article addresses the ethical and methodological issues of representivity, ownership, anonymity and confidentiality. It also explores the importance of investment in relationships in migration narrative research, but also the difficulties that arise when professional and personal boundaries become blurred.

Isotopic characterization of lifetime movement by two demersal fishes from the northeastern Gulf of Mexico

2021 ◽  
Vol 657 ◽  
pp. 161-172
Author(s):  
JL Vecchio ◽  
JL Ostroff ◽  
EB Peebles
Keyword(s):  
Gulf Of Mexico ◽  
Continental Shelf ◽  
Life Histories ◽  
Linear Mixed Model ◽  
Trophic Position ◽  
Eye Lens ◽  
Outer Continental Shelf ◽  
Red Grouper ◽  
Lens Diameter ◽  
Isotopic Characterization

An understanding of lifetime trophic changes and ontogenetic habitat shifts is essential to the preservation of marine fish species. We used carbon and nitrogen stable isotope values (δ13C and δ15N) recorded within the laminar structure of fish eye lenses, reflecting both diet and location over time, to compare the lifetime trends of 2 demersal mesopredators. Tilefish Lopholatilus chamaeleonticeps inhabit burrows on the outer continental shelf, which results in exceptional site fidelity. Red grouper Epinephelus morio are spawned on the middle to outer continental shelf, move to the inner shelf for the juvenile period, and return offshore upon sexual maturity. Both species inhabit the eastern Gulf of Mexico, a region with a distinctive offshore-inshore gradient in background δ13C values. Within individual tilefish (n = 36), sequences of δ13C values and δ15N values had strong, positive correlations with eye-lens diameter, and strong correlations between the 2 isotopes (mean Spearman r = 0.86), reflecting an increase in trophic position with growth and little lifetime movement. In red grouper (n = 30), δ15N values positively correlated with eye-lens diameter, but correlations between δ15N and δ13C were weak (mean Spearman r = 0.29), suggesting cross-shelf ontogenetic movements. Linear mixed model results indicated strong relationships between δ15N and δ13C values in tilefish eye lenses but no convergence in the red grouper model. Collectively, these results are consistent with previously established differences in the life histories of the 2 species, demonstrating the potential utility of eye-lens isotope records, particularly for investigating the life histories of lesser-known species.

From source-oriented databases to event-history data files: a twelve-step action plan for the analysis of individual and household life histories

1998 ◽  
Vol 10 (1-3) ◽  
pp. 1-9
Author(s):  
Onno Boonstra ◽  
Maarten Panhuysen
Keyword(s):  
Life Histories ◽  
Event History Analysis ◽  
Action Plan ◽  
Event History ◽  
Flat File ◽  
Event History Data ◽  
History Analysis ◽  
Good Technique ◽  
Data Files ◽  
The Way

Population registers are recognised to be a very important source for demographic research, because it enables us to study the lifecourse of individuals as well as households. A very good technique for lifecourse analysis is event history analysis. Unfortunately, there are marked differences in the way the data are available in population registers and the way event history analysis expects them to be. The source-oriented approach of computing historical data calls for a ‘five-file structure’, whereas event history analysis only can handle fiat files. In this article, we suggest a series of twelve steps with which population register data can be transposed from a five-file structured database into a ‘flat file’ event history analysis dataset.

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