The Relationship between Soil Fertility and Fire-Stimulated Floral Induction in Two Populations of Grass-Leaved Golden Aster, Pityopsis graminifolia

Oikos ◽  
1995 ◽  
Vol 74 (1) ◽  
pp. 45 ◽  
Author(s):  
J. Stephen Brewer
Keyword(s):  
Soil Fertility ◽  
Floral Induction ◽  
Pityopsis Graminifolia ◽  
The Relationship ◽  
Two Populations

K-MEANS CLUSTERING ALGORITHM BASED CLASSIFICATION OF SOIL FERTILITY IN NORTH WEST NIGERIA

2020 ◽  
Vol 4 (2) ◽  
pp. 780-787
Author(s):  
Ibrahim Hassan Hayatu ◽  
Abdullahi Mohammed ◽  
Barroon Ahmad Isma’eel ◽  
Sahabi Yusuf Ali
Keyword(s):  
Soil Fertility ◽  
Crop Yield ◽  
Clustering Algorithm ◽  
Soil Samples ◽  
North West ◽  
R Programming ◽  
Available Information ◽  
Northwest Region ◽  
The Relationship

Soil fertility determines a plant's development process that guarantees food sufficiency and the security of lives and properties through bumper harvests. The fertility of soil varies according to regions, thereby determining the type of crops to be planted. However, there is no repository or any source of information about the fertility of the soil in any region in Nigeria especially the Northwest of the country. The only available information is soil samples with their attributes which gives little or no information to the average farmer. This has affected crop yield in all the regions, more particularly the Northwest region, thus resulting in lower food production.  Therefore, this study is aimed at classifying soil data based on their fertility in the Northwest region of Nigeria using R programming. Data were obtained from the department of soil science from Ahmadu Bello University, Zaria. The data contain 400 soil samples containing 13 attributes. The relationship between soil attributes was observed based on the data. K-means clustering algorithm was employed in analyzing soil fertility clusters. Four clusters were identified with cluster 1 having the highest fertility, followed by 2 and the fertility decreases with an increasing number of clusters. The identification of the most fertile clusters will guide farmers on where best to concentrate on when planting their crops in order to improve productivity and crop yield.

scholarly journals Linkage Disequilibrium in Domestic Sheep

Genetics ◽  
2002 ◽  
Vol 160 (3) ◽  
pp. 1113-1122
Author(s):  
A F McRae ◽  
J C McEwan ◽  
K G Dodds ◽  
T Wilson ◽  
A M Crawford ◽  
...  
Keyword(s):  
Linkage Disequilibrium ◽  
Type I Error ◽  
Statistical Significance ◽  
Domestic Sheep ◽  
Type I ◽  
Single Nucleotide ◽  
Microsatellite Genotype ◽  
Marker Distance ◽  
The Relationship ◽  
Two Populations

Abstract The last decade has seen a dramatic increase in the number of livestock QTL mapping studies. The next challenge awaiting livestock geneticists is to determine the actual genes responsible for variation of economically important traits. With the advent of high density single nucleotide polymorphism (SNP) maps, it may be possible to fine map genes by exploiting linkage disequilibrium between genes of interest and adjacent markers. However, the extent of linkage disequilibrium (LD) is generally unknown for livestock populations. In this article microsatellite genotype data are used to assess the extent of LD in two populations of domestic sheep. High levels of LD were found to extend for tens of centimorgans and declined as a function of marker distance. However, LD was also frequently observed between unlinked markers. The prospects for LD mapping in livestock appear encouraging provided that type I error can be minimized. Properties of the multiallelic LD coefficient D′ were also explored. D′ was found to be significantly related to marker heterozygosity, although the relationship did not appear to unduly influence the overall conclusions. Of potentially greater concern was the observation that D′ may be skewed when rare alleles are present. It is recommended that the statistical significance of LD is used in conjunction with coefficients such as D′ to determine the true extent of LD.

Sources of morphological variation and organization within and among populations of Balsamorhiza sagittata

1988 ◽  
Vol 66 (1) ◽  
pp. 11-17 ◽  
Author(s):  
K. A. Robson ◽  
R. K. Scagel ◽  
J. Maze
Keyword(s):  
Open Systems ◽  
Second Law Of Thermodynamics ◽  
Population Diversity ◽  
Individual Plant ◽  
Theory Of Evolution ◽  
Plant Parts ◽  
The Individual ◽  
The Relationship ◽  
Balsamorhiza Sagittata ◽  
Two Populations

Comparisons of differences between morphological means of individual plant parts indicate that the greatest source of variation in two populations of Balsamorhiza sagittata is the individual plants within populations; within-population diversity is greater than among-population diversity. Variable covariance and correlations differ between individual plants and there are subgroups of interrelated variables that can be tied to developmental phenomena. The relationship between developmental phenomena and these groups of variables suggests a relationship between organizational, as reflected in variable interrelationships, and ontogenetic variation. These results are not adequately explained by neoDarwinian theory but are explained more comprehensively by a theory of evolution that views biological change over time as an intrinsically driven self-organization, accompanied by an increase in complexity (a manifestation of the "Second Law of Thermodynamics" as it applies to open systems).

Existentials and possessives in Modern Hebrew

2018 ◽  
Vol 42 (2) ◽  
pp. 389-417
Author(s):  
Nurit Melnik
Keyword(s):  
Language Change ◽  
Age Groups ◽  
Spoken Language ◽  
Possessive Constructions ◽  
Usage Patterns ◽  
Modern Hebrew ◽  
Time Periods ◽  
Additional Support ◽  
The Relationship ◽  
Two Populations

Abstract This paper considers the relationship between synchronic variation and language change in the context of the existential and possessive constructions in Modern Hebrew, which exhibit a normative – colloquial alternation. The study examines usage patterns across age groups and time periods, as represented in spoken-language corpora. It shows that the non-normative construction is used extensively in the contemporary speech of adults. Moreover, a comparison of the use of the normative – colloquial alternations by two populations, children and adults, in different time periods, provides evidence to suggest that these constructions are undergoing language change. A cross-linguistic perspective lends additional support: across languages the expression of existence involves non-canonical structures, which are particularly susceptible to language variation and, possibly, language change.

Identification of two species of alpha motoneurons in cat's plantaris pool

1977 ◽  
Vol 40 (1) ◽  
pp. 16-25 ◽  
Author(s):  
D. A. Harris ◽  
E. Henneman
Keyword(s):  
Visual Inspection ◽  
Repetitive Stimulation ◽  
Ventral Root ◽  
Statistical Analyses ◽  
The Other ◽  
Small Samples ◽  
The Relationship ◽  
Decerebrate Cats ◽  
Two Populations ◽  
Stimulation Of

1. Single units of the plantaris pool were isolated in ventral root filaments of decerebrate cats and their critical firing levels (CFLs) were determined. Motoneurons of similar size, as judged by their CFLs and other criteria, were compared in firing rate (FR) during repetitive stimulation of the plantaris nerve. 2. Such units either differed very little or quite widely, suggesting that they were sampled randomly from two populations, one firing rapidly, the other slowly. The relationship between the two rates remained approximately constant, regardless of the intensity or rate of input the units received, as long as both of them discharged rhythmically. 3. In single experiments 10-15 of the smallest units in the pool (all with CFLs in the 0-8% range) were isolated and compared. Statistical analyses and visual inspection of these small samples again suggested the existence of two species of motoneurons. 4. Statistical analyses also indicated that the FRs of units in single experiments were not sampled from any one of a variety of parametric, single-modal distributions. This suggests that the data were sampled from a distribution having more than one mode, indicating the existence of separate populations or species of motoneurons among the small units of the pool (0-8% range of CFL). 5. Pooling of the normalized data from different experiments revealed a bimodal histogram, reinforcing the conclusion that there are two species of small alpha motoneurons in the plantaris pool.

The relationship between the dwarfing gene and E. coli infection in two populations of chickens

1981 ◽  
Vol 72 (2) ◽  
pp. 125-126 ◽  
Author(s):  
J. M. Mauldin ◽  
F. A. Marsteller ◽  
W. B. Gross ◽  
P. B. Siegel
Keyword(s):  
Dwarfing Gene ◽  
E Coli ◽  
The Relationship ◽  
Two Populations

Being black in Australia: a case study of intergroup relations

Race & Class ◽  
2008 ◽  
Vol 49 (4) ◽  
pp. 38-56 ◽  
Author(s):  
Val Colic-Peisker ◽  
Farida Tilbury
Keyword(s):  
Predominantly White ◽  
Race Relations ◽  
Intergroup Relations ◽  
Youth Violence ◽  
Economic Status ◽  
Racial Hierarchy ◽  
History Of ◽  
The Relationship ◽  
Two Populations

This article presents a case study in Australia's race relations, focusing on tensions between urban Aborigines and recently resettled African refugees, particularly among young people. Both of these groups are of low socio-economic status and are highly visible in the context of a predominantly white Australia. The relationship between them, it is argued, reflects the history of strained race relations in modern Australia and a growing antipathy to multiculturalism. Specific reasons for the tensions between the two populations are suggested, in particular, perceptions of competition for material (housing, welfare, education) and symbolic (position in a racial hierarchy) resources. Finally, it is argued that the phenomenon is deeply embedded in class and race issues, rather than simply in youth violence.

A scheme for preliminary study of soil fertility in a district

1970 ◽  
Vol 10 (43) ◽  
pp. 196
Author(s):  
WM McArthur ◽  
K Spencer
Keyword(s):  
Soil Fertility ◽  
New South ◽  
Strong Correlations ◽  
South Wales ◽  
The Status ◽  
Using Data ◽  
Distribution Of Components ◽  
Edaphic Variables ◽  
The Relationship ◽  
Field Plots

A scheme is proposed as a basis for soil fertility studies in areas where little information is available. The first stage consists of sampling the area on a grid and determining the patterns of variation in the status of those nutrient elements likely to be deficient. These patterns are then compared with intensity patterns of environmental (including edaphic) variables. Where the two sets of variables can be quantified, regression analysis may be used to estimate the closeness of the relationship ; otherwise the relationship must be assessed visually from the degree of conformity between patterns. Those environmental variables that relate, causally or otherwise, to the distribution of components of chemical fertility are identified by strong correlations. Information so gained may be used in subsequent agronomic studies, both as a guide to number and location of field plots and as a framework for studies in soil chemistry and pedology. The scheme is illustrated using data derived from studies on the Dorrigo Plateau of New South Wales. Factors relating closely to phosphorus, sulphur, molybdenum, and nitrogen distribution were identified. In no case could one factor be used to predict the adequacy of all nutrients.

scholarly journals Comparative analysis of shell occupation by two southern populations of the hermit crab Loxopagurus loxochelis (Decapoda, Diogenidae)

2012 ◽  
Vol 60 (3) ◽  
pp. 299-310 ◽  
Author(s):  
Luciane Ayres-Peres ◽  
Aline Ferreira Quadros ◽  
Fernando L. Mantelatto
Keyword(s):  
Principal Component Analysis ◽  
Comparative Analysis ◽  
Hermit Crab ◽  
Regression Tree ◽  
Principal Component ◽  
Hermit Crabs ◽  
Pca Analysis ◽  
Internal Volume ◽  
The Relationship ◽  
Two Populations

The present study aimed to comparatively verify the relation between the hermit crabs and the shells they use in two populations of Loxopagurus loxochelis. Samples were collected monthly from July 2002 to June 2003, at Caraguatatuba and Ubatuba Bay, São Paulo, Brazil. The animals sampled had their sex identified, were weighed and measured; their shells were identified, measured and weighed, and their internal volume determined. To relate the hermit crab's characteristics and the shells' variables, principal component analysis (PCA) and a regression tree were used. According to the PCA analysis, the three gastropod shells most frequently used by L. loxochelis varied in size. The regression tree successfully explained the relationship between the hermit crab's characteristics and the internal volume of the inhabited shell. It can be inferred that the relationship between the morphometry of an individual hermit crab and its shell is not straightforward and it is impossible to explain only on the basis of direct correlations between the body's and the shell's attributes. Several factors (such as the morphometry and the availability of the shell, environmental conditions and inter- and intraspecific competition) interact and seem to be taken into consideration by the hermit crabs when they choose a shell, resulting in the diversified pattern of shell occupancy shown here and elsewhere.

Sign in / Sign up

Export Citation Format

Share Document