Relation of geographic variation in the skull of Microtus pennsylvanicus to climate

1983 ◽  
Vol 61 (6) ◽  
pp. 1232-1241 ◽  
Author(s):  
Richard R. Snell ◽  
Kimberly M. Cunnison
Keyword(s):  
Low Temperature ◽  
Geographic Variation ◽  
Multiple Regression ◽  
Minimum Spanning Tree ◽  
Climatic Factors ◽  
Principal Component ◽  
Microtus Pennsylvanicus ◽  
Annual Number ◽  
Simple Correlation ◽  
Morphometric Variation

Analyses of geographic variation in the skull of meadow voles (Microtus pennsylvanicus) indicate that phenetic distances among samples are not related to geographic distance: a minimum spanning tree based on average taxonomic distance superimposed on a map of 38 localities provides no particular phenetic clustering of those samples geographically proximate. A multiple regression of phenetic component one (skull size) onto orthogonally rotated climatic factors explains much less morphometric variation (25.6%) than a simple correlation with recorded extreme low temperature (38.9%). Multiple regression of phenetic principal component two (interorbital width) onto the same climatic factors explains minimally more morphological variation (42.1%) than a simple correlation with mean annual number of days with frost (41.7%). Microtus pennsylvanicus shows a pattern of size variation that is the reverse of Bergmann's rule: these voles are large where it is warm and small where it is cold. Since small size reduces total energy expenditure, we predict that during times of extreme low temperature (i) smaller voles will be less energetically stressed than larger voles and (ii) large size will be actively selected against.

scholarly journals Radial Growth Response of European Larch Provenances to Interannual Climate Variation in Poland

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 334
Author(s):  
Norbert Szymański ◽  
Sławomir Wilczyński
Keyword(s):  
Radial Growth ◽  
Climatic Factors ◽  
Principal Component ◽  
Climatic Conditions ◽  
Growth Responses ◽  
European Larch ◽  
Temperature And Precipitation ◽  
Provenance Trials ◽  
High Precipitation ◽  
Climatic Elements

The present study identified the similarities and differences in the radial growth responses of 20 provenances of 51-year-old European larch (Larix decidua Mill.) trees from Poland to the climatic conditions at three provenance trials situated in the Polish lowlands (Siemianice), uplands (Bliżyn) and mountains (Krynica). A chronology of radial growth indices was developed for each of 60 European larch populations, which highlighted the interannual variations in the climate-mediated radial growth of their trees. With the aid of principal component, correlation and multiple regression analysis, supra-regional climatic elements were identified to which all the larch provenances reacted similarly at all three provenance trials. They increased the radial growth in years with a short, warm and precipitation-rich winter; a cool and humid summer and when high precipitation in late autumn of the previous year was noted. Moreover, other climatic elements were identified to which two groups of the larch provenances reacted differently at each provenance trial. In the lowland climate, the provenances reacted differently to temperature in November to December of the previous year and July and to precipitation in September. In the upland climate, the provenances differed in growth sensitivity to precipitation in October of the previous year and June–September. In the mountain climate, the provenances responded differently to temperature and precipitation in September of the previous year and to precipitation in February, June and September of the year of tree ring formation. The results imply that both climatic factors and origin (genotype), i.e., the genetic factor, mediate the climate–growth relationships of larch provenances.

scholarly journals Low-temperature thermal hydrolysis of sludge prior to anaerobic digestion: principal component analysis (PCA) of experimental data

Data in Brief ◽  
2021 ◽  
pp. 107323
Author(s):  
Mohamed N.A. Meshref ◽  
Seyed Mohammad Mirsoleimani Azizi ◽  
Wafa Dastyar ◽  
Rasha Maal-Bared ◽  
Bipro Ranjan Dhar
Keyword(s):  
Experimental Data ◽  
Principal Component Analysis ◽  
Anaerobic Digestion ◽  
Low Temperature ◽  
Principal Component ◽  
Component Analysis ◽  
Thermal Hydrolysis ◽  
Hydrolysis Of

The Relative Importance of Socioeconomic and Political Variables for Public Policy

1977 ◽  
Vol 71 (2) ◽  
pp. 559-566 ◽  
Author(s):  
Michael S. Lewis-Beck
Keyword(s):  
Public Policy ◽  
Path Analysis ◽  
Multiple Regression ◽  
Partial Correlation ◽  
Policy Outcomes ◽  
Statistical Techniques ◽  
Relative Importance ◽  
Simple Correlation ◽  
Independent Variables ◽  
Political Variables

Since Dawson and Robinson, a dominant issue in the quantitative study of public policy has been the relative importance of socioeconomic and political variables for determining policy outcomes. It is argued here that past efforts to resolve this issue have been unsatisfactory, largely because they relied on inadequate statistical techniques, i.e., simple correlation, partial correlation, or multiple regression. Coefficients from these techniques are irrelevant for all but the most peculiar models of public policy. In general, if the researcher wishes to assess the relative importance of independent variables, it will be necessary to resort to path analysis of a formally constructed causal model. The comparison of “effects coefficients,” derived from path analysis, is offered as the preferred means of evaluating independent variables, superior to comparisons of coefficients from simple correlation, partial correlation, or multiple regression. When the effects coefficients are actually calculated for a popular model of welfare policy, socioeconomic variables appear much more important than political variables, contrary to interpretations coming from the more traditional statistical techniques.

scholarly journals The optimal number of partial least squares components in genomic selection for pork pH

2017 ◽  
Vol 47 (1) ◽  
Author(s):  
Fernanda Gomes da Silveira ◽  
Darlene Ana Souza Duarte ◽  
Lucas Monteiro Chaves ◽  
Fabyano Fonseca e Silva ◽  
Ivan Carvalho Filho ◽  
...  
Keyword(s):  
Least Squares ◽  
Genomic Selection ◽  
Multiple Regression ◽  
Partial Least Squares ◽  
Predictive Accuracy ◽  
Principal Component ◽  
Theoretical Background ◽  
Optimal Number ◽  
Number Of Components ◽  
Regression Techniques

ABSTRACT: The main application of genomic selection (GS) is the early identification of genetically superior animals for traits difficult-to-measure or lately evaluated, such as meat pH (measured after slaughter). Because the number of markers in GS is generally larger than the number of genotyped animals and these markers are highly correlated owing to linkage disequilibrium, statistical methods based on dimensionality reduction have been proposed. Among them, the partial least squares (PLS) technique stands out, because of its simplicity and high predictive accuracy. However, choosing the optimal number of components remains a relevant issue for PLS applications. Thus, we applied PLS (and principal component and traditional multiple regression) techniques to GS for pork pH traits (with pH measured at 45min and 24h after slaughter) and also identified the optimal number of PLS components based on the degree-of-freedom (DoF) and cross-validation (CV) methods. The PLS method out performs the principal component and traditional multiple regression techniques, enabling satisfactory predictions for pork pH traits using only genotypic data (low-density SNP panel). Furthermore, the SNP marker estimates from PLS revealed a relevant region on chromosome 4, which may affect these traits. The DoF and CV methods showed similar results for determining the optimal number of components in PLS analysis; thus, from the statistical viewpoint, the DoF method should be preferred because of its theoretical background (based on the "statistical information theory"), whereas CV is an empirical method based on computational effort.

scholarly journals Development of Korean Indigenous Low-Temperature-Tolerant Yeast for Enhancing the Flavor of Yakju

Fermentation ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 260
Author(s):  
Jong-Beom Park ◽  
Jun-Su Choi ◽  
Hye-Won Park ◽  
Sae-Byuk Lee ◽  
Heui-Dong Park
Keyword(s):  
Low Temperature ◽  
Aromatic Compounds ◽  
Raw Materials ◽  
Principal Component ◽  
Isoamyl Alcohol ◽  
Pichia Kudriavzevii ◽  
Fermented Beverage ◽  
Ethyl Hexadecanoate ◽  
Phenethyl Acetate ◽  
Volatile Aromatic Compounds

Yakju, a traditional fermented beverage in Korea, is prepared using various raw materials and methods, and, hence, exhibits various characteristics. Low-temperature-fermented yakju can inhibit the growth of undesirable bacteria and is known for its unique flavor and refreshing taste. To increase the production of volatile aromatic compounds in yakju, strains with strong resistance to low temperatures and excellent production of volatile aromatic compounds were screened from indigenous fruits (grape, persimmon, plum, aronia, wild grape) and nuruk in Korea. One Saccharomyces cerevisiae and three non-Saccharomyces strains were finally screened, and yakju was fermented at 15 °C through mono/co-culture. The analysis of volatile aromatic compounds showed that S. cerevisiae W153 produced 1.5 times more isoamyl alcohol than the control strain and reduced the production of 2,3-butanediol by a third. Similarly, a single culture of Pichia kudriavzevii N373 also produced 237.7 mg/L of ethyl acetate, whereas Hanseniaspora vineae G818 produced ~11 times greater levels of 2-phenethyl acetate than the control. Alternatively, Wickerhamomyces anomalus A159 produced 95.88 mg/L of ethyl hexadecanoate. During principal component analysis, we also observed that the co-culture sample exhibited characteristics of both volatile aroma compounds of the single cultured sample of each strain. Our results suggest that yakju with unique properties can be prepared using various non-Saccharomyces strains.

scholarly journals Environmental factors affecting coffee (Coffea arabica L., Var. Castillo) quality in Colombia Southern

2020 ◽  
Vol 37 (2) ◽  
Author(s):  
Claudia Patricia Criollo-Velásquez ◽  
Johana Alixa Muñoz-Belalcazar ◽  
Tulio César Lagos-Burbano
Keyword(s):  
Climatic Factors ◽  
Principal Component ◽  
Average Score ◽  
Nutritional Factors ◽  
Factors Affecting ◽  
Thermal Amplitude ◽  
And Cluster Analysis ◽  
Soil Climate ◽  
Cup Quality

The determinant factors of coffee cup quality are highly variable and depend on their interaction with coffee production and benefit. This study aimed to analyze soil and climatic factors and their association with the cup quality of Castillo coffee variety of three to five years of age from production units in ecotypes 220A and 221A of the Department of Nariño. The study farms were located in three different altitudinal ranges: ≤1500 m, between 1501 and 1700 m, and >1700 m. Soil, climate, and coffee cup quality variables were analyzed through principal component analysis and cluster analysis. A low level of association was found between climatic and soil nutritional factors and coffee cup quality. Soil Mn, Fe, and Cu contents showed the highest association levels with cup quality, indicated by an average score of 80.89. The highest values of photosynthetically active radiation -PAR- and thermal amplitude were found in La Unión - Nariño, and these variables were associated with the group that obtained the highest cup quality score (82.58). Cup quality was not associated with elevation since the highest scores (85.5 and 82.33) were obtained from production units located at ≤1500 m.a.s.l. and >1700 m.a.s.l, respectively.

scholarly journals Geographic variation in the morphology of the sand-dwelling lizard Nothobachia ablephara (Squamata: Gymnophthalmidae)

2019 ◽  
Vol 18 (2) ◽  
pp. 195-207
Author(s):  
Carolina Nisa Ramiro ◽  
Renato Sousa Recoder ◽  
Miguel Trefaut Rodrigues
Keyword(s):  
Geographic Variation ◽  
Morphological Traits ◽  
Geographical Variation ◽  
Multivariate Analyses ◽  
Molecular Study ◽  
Northeastern Brazil ◽  
Sexually Dimorphic ◽  
Morphometric Variation ◽  
The One ◽  
Two Populations

Geographic variation in the morphology of the sand-dwelling lizard Nothobachia ablephara (Squamata: Gymnophthalmidae). Nothobachia ablephara is a small microteiid lizard with an elongated body and reduced limbs; it occurs in isolated dune felds in the state of Bahia (Xique-Xique and Alagoado) and small sandy patches in northeastern Brazil. A previous molecular study found a marked mtDNA divergence between populations of N. ablephara from Alagoado and Xique-Xique dunes, suggesting that the two populations diverged from one another between 3 and 4 million years ago. Given this isolation, it is interesting to explore whether morphological traits of the lizards refect the reported genetic divergence of the populations. Scale counts of the sexes and the populations differ signifcantly, but there is considerable overlap of values. Univariate and multivariate analyses revealed signifcant morphometric variation between sexes and populations; however, this is mostly explained by size differences. Females are larger than males in all characters that are sexually dimorphic, and individuals from Xique-Xique are larger than those from Alagoado in all characters that vary geographically. The sample from Alagoado has more sexually dimorphic characters than the one from Xique-Xique. Although N. ablephara displays some geographical variation, the two populations could not be unequivocally distinguished by scale counts and morphometric data.

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