scholarly journals Temporal and Spatial Variations in the Twinning Rate in Norway

2016 ◽  
Vol 19 (4) ◽  
pp. 359-366 ◽  
Author(s):  
Johan Fellman
Keyword(s):  
Regression Model ◽  
Spatial Variation ◽  
Temporal Variation ◽  
Regional Variation ◽  
Goodness Of Fit ◽  
Spatial Models ◽  
Progressive Increase ◽  
African Origin ◽  
Geographical Variations ◽  
Temporal And Spatial

Strong geographical variations have been noted in the twinning rate (TWR). In general, the rate is high among people of African origin, intermediate among Europeans, and low among most Asiatic populations. In Europe, there tends to be a south–north cline, with a progressive increase in the TWR from south to north and a minimum around the Basque provinces. The highest TWRs in Europe have been found among the Nordic populations. Furthermore, within larger populations, small isolated subpopulations have been identified to have extreme, mainly high, TWRs. In the study of the temporal variation of the TWR in Norway, we consider the period from 1900 to 2014. The regional variation of the TWR in Norway is analyzed for the different counties for two periods, 1916–1926 and 1960–1988. Heterogeneity between the regional TWRs in Norway during 1916–1926 was found, but the goodness of fit for the alternative spatial models was only slight. The optimal regression model for the TWR in Norway has the longitude and its square as regressors. According to this model, the spatial variation is distributed in a west–east direction. For 1960–1988, no significant regional variation was observed. One may expect that the environmental and genetic differences between the counties in Norway have disappeared and that the regional TWRs have converged towards a common low level.

Spatial Variation in the Twinning Rate in Sweden, 1751–1850

2009 ◽  
Vol 12 (6) ◽  
pp. 583-590 ◽  
Author(s):  
Johan Fellman ◽  
Aldur W. Eriksson
Keyword(s):  
Spatial Variation ◽  
19Th Century ◽  
Regional Variation ◽  
Progressive Increase ◽  
Genetic Differences ◽  
African Origin ◽  
Optimal Model ◽  
Geographical Variations ◽  
The 19Th Century

AbstractStrong geographical variations in the twinning rate have been presented in the literature. In general, the rate is high among people of African origin, intermediate among Europeans and low among most Asiatic populations. In Europe, a progressive increase has occurred in the twinning rate from south to north, with a minimum around the Basque provinces. The highest twinning rates in Europe have been found among Nordic populations with the exception of the Saamis (Lapps). Within larger populations, some small isolated subpopulations have been identified to have extreme, mainly high, twinning rates. In this study, we investigated the regional variation of the twinning rate in Sweden. We analysed twinning rates for different counties for the period 1751–1850. From the middle of the 19th century, the environmental and genetic differences have decreased and the regional twinning rates have converged towards a common decreased level. The models applied have the geographical coordinates as regressors. The optimal model for the twinning rate has the longitude, the latitude and their product as regressors, indicating both horizontal and vertical trends. According to this model, the maximum twinning rate in Sweden is located in the eastern part of central Sweden, mainly on the island of Gotland and in the counties around Stockholm. Relatively low twinning rates are seen in the western and northern parts of Sweden.

scholarly journals Phylogenetic paleoecology: macroecology within an evolutionary framework

Paleobiology ◽  
2021 ◽  
Vol 47 (2) ◽  
pp. 171-177
Author(s):  
James C. Lamsdell ◽  
Curtis R. Congreve
Keyword(s):  
Species Diversity ◽  
Spatial Variation ◽  
Geographic Distribution ◽  
Evolutionary Biology ◽  
Phylogenetic Signal ◽  
Evolutionary Rates ◽  
The Other ◽  
Ecological Data ◽  
Temporal And Spatial Variation ◽  
Temporal And Spatial

The burgeoning field of phylogenetic paleoecology (Lamsdell et al. 2017) represents a synthesis of the related but differently focused fields of macroecology (Brown 1995) and macroevolution (Stanley 1975). Through a combination of the data and methods of both disciplines, phylogenetic paleoecology leverages phylogenetic theory and quantitative paleoecology to explain the temporal and spatial variation in species diversity, distribution, and disparity. Phylogenetic paleoecology is ideally situated to elucidate many fundamental issues in evolutionary biology, including the generation of new phenotypes and occupation of previously unexploited environments; the nature of relationships among character change, ecology, and evolutionary rates; determinants of the geographic distribution of species and clades; and the underlying phylogenetic signal of ecological selectivity in extinctions and radiations. This is because phylogenetic paleoecology explicitly recognizes and incorporates the quasi-independent nature of evolutionary and ecological data as expressed in the dual biological hierarchies (Eldredge and Salthe 1984; Congreve et al. 2018; Fig. 1), incorporating both as covarying factors rather than focusing on one and treating the other as error within the dataset.

scholarly journals Spatial and Temporal Variation in Microbial Diversity and Community Structure in a Contaminated Mangrove Wetland

2020 ◽  
Vol 10 (17) ◽  
pp. 5850
Author(s):  
Jiaojiao Ma ◽  
Ting Zhou ◽  
Chunyu Xu ◽  
Dawen Shen ◽  
Songjun Xu ◽  
...  
Keyword(s):  
Community Structure ◽  
Spatial Variation ◽  
Temporal Variation ◽  
Bacterial Diversity ◽  
Diversity Index ◽  
Total Carbon ◽  
Spatial And Temporal Variation ◽  
Rrna Gene ◽  
Mangrove Wetland ◽  
Mangrove Soils

Field and laboratory investigations were conducted to characterize bacterial diversity and community structure in a badly contaminated mangrove wetland adjacent to the metropolitan area of a megacity in subtropical China. Next-generation sequencing technique was used for sequencing the V4–V5 region of the 16s rRNA gene on the Illumina system. Collectively, Proteobacteria, Chloroflexi, Planctomycetes, Actinobacteria and Bacteroidetes were the predominant phyla identified in the investigated soils. A significant spatial variation in bacterial diversity and community structure was observed for the investigated mangrove soils. Heavy metal pollution played a key role in reducing the bacterial diversity. The spatial variation in soil-borne heavy metals shaped the spatial variation in bacterial diversity and community structure in the study area. Other environmental factors such as total carbon and total nitrogen in the soils that are affected by seasonal change in temperature could also influence the bacterial abundance, diversity and community structure though the temporal variation was relatively weaker, as compared to spatial variation. The bacterial diversity index was lower in the investigated site than in the comparable reference site with less contaminated status. The community structure in mangrove soils at the current study site was, to a remarkable extent, different from those in the tropical mangrove wetlands around the world.

scholarly journals Spatial distribution and temporal variation of microcrustaceans assembly (Cladocera and Copepoda) in different compartments of a reservoir in the brazilian semiarid region

2018 ◽  
Vol 30 (0) ◽  
Author(s):  
Josiane Souza Santos ◽  
Nadson Ressyé Simões ◽  
Sérgio Luiz Sonoda
Keyword(s):  
Spatial Distribution ◽  
Spatial Variation ◽  
Temporal Variation ◽  
Aquatic Macrophytes ◽  
Temporal Dynamics ◽  
Lateral Compartment ◽  
Spatial And Temporal Variation ◽  
Semiarid Region ◽  
Brazilian Semiarid ◽  
Significant Spatial Variation

Abstract Aim: The objective of this study was to investigate the spatial and temporal variation of microcrustacean assemblages of a reservoir in the Brazilian semiarid region. Methods Physical and chemical water variables and samples of microcrustaceans were collected at eight sites of the reservoir between July 2013 and November 2014, in a total of seven campaigns. For this study, the reservoir was categorized in two compartments: lateral and central. Results Limnological variables showed significant temporal variation (PERMANOVA, Pseudo-F = 19.51, p = 0.001). Higher turbidity values and suspended solids were observed in the rainiest months, while during the dry months, we measured higher values of transparency, dissolved oxygen, and chlorophyll-a. It was not found significant spatial variation of limnological variables (PERMANOVA, Pseudo-F = 0.96; p = 0.394). During the study period, ten species were recorded: four Cladocera (Ceriodaphnia cornuta, Daphnia gessneri, Diaphanosoma birgei and Diaphanosoma spinulosum ) three Copepoda Calanoida (Argyrodiaptomus azevedoi, Notodiaptomus cearensis and Notodiaptomus iheringi) and three Copepoda Cyclopoida (Macrocyclops albidus, Thermocyclops minutus and Thermocyclops decipiens). The microcrustacean assemblages showed significant temporal variation (PERMANOVA, Pseudo-F = 4.34; p = 0.001) as well as significant spatial variation (PERMANOVA, Pseudo-F = 9.46; p = 0.001). The highest values of abundance and richness were observed in the lateral compartment, this result is mainly related to the presence of aquatic macrophytes in this region, because the analysis of partial RDA indicated that limnological variables explained only 11% of this variation (Pseudo-F = 2.08, p = 0.001). Conclusions The results suggest that the seasonality of the semiarid is an important factor in the temporal dynamics of the limnological variables, while the aquatic macrophytes play an important role in the spatial distribution of the microcrustacean assembly.

Temporal and spatial variation in concentrations of trace metals in coastal sediments from the Ninety Mile Beach, Victoria, Australia

1995 ◽  
Vol 30 (6) ◽  
pp. 414-418 ◽  
Author(s):  
David Haynes ◽  
David Toohey ◽  
Debra Clarke ◽  
Donovan Marney
Keyword(s):  
Trace Metals ◽  
Spatial Variation ◽  
Coastal Sediments ◽  
Temporal And Spatial Variation ◽  
Temporal And Spatial
Sign in / Sign up

Export Citation Format

Share Document