Artículos de revistas: "Tests de Mantel"

1

Guillot, Gilles y François Rousset. "Dismantling the Mantel tests". Methods in Ecology and Evolution 4, n.º 4 (17 de enero de 2013): 336–44. http://dx.doi.org/10.1111/2041-210x.12018.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

2

Raufaste, Nathalie y François Rousset. "ARE PARTIAL MANTEL TESTS ADEQUATE?" Evolution 55, n.º 8 (2001): 1703. http://dx.doi.org/10.1554/0014-3820(2001)055[1703:apmta]2.0.co;2.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

3

Raufaste, Nathalie y François Rousset. "ARE PARTIAL MANTEL TESTS ADEQUATE?" Evolution 55, n.º 8 (agosto de 2001): 1703–5. http://dx.doi.org/10.1111/j.0014-3820.2001.tb00689.x.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

4

Rayner, J. C. W. y D. J. Best. "Unconditional analogues of Cochran-Mantel-Haenszel tests". Australian & New Zealand Journal of Statistics 59, n.º 4 (diciembre de 2017): 485–94. http://dx.doi.org/10.1111/anzs.12215.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

5

Rayner, J. C. W. y Glen Livingston. "The Kruskal–Wallis tests are Cochran–Mantel–Haenszel mean score tests". METRON 78, n.º 3 (10 de noviembre de 2020): 353–60. http://dx.doi.org/10.1007/s40300-020-00192-4.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

6

Rayner, J. y Paul Rippon. "Recent Extensions to the Cochran–Mantel–Haenszel Tests". Stats 1, n.º 1 (26 de septiembre de 2018): 98–111. http://dx.doi.org/10.3390/stats1010008.

Texto completo

Resumen

The Cochran–Mantel–Haenszel (CMH) methodology is a suite of tests applicable to particular tables of count data. The inference is conditional on the treatment and outcome totals on each stratum being known before sighting the data. The CMH tests are important for analysing randomised blocks data when the responses are categorical rather than continuous. This overview of some recent extensions to CMH testing first describes the traditional CMH tests and then explores new alternative presentations of the ordinal CMH tests. Next, the ordinal CMH tests will be extended so they can be used to test for higher moment effects. Finally, unconditional analogues of the extended CMH tests will be developed.

Los estilos APA, Harvard, Vancouver, ISO, etc.

7

Rousset, François. "PARTIAL MANTEL TESTS: REPLY TO CASTELLANO AND BALLETTO". Evolution 56, n.º 9 (2002): 1874. http://dx.doi.org/10.1554/0014-3820(2002)056[1874:pmtrtc]2.0.co;2.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

8

Rousset, Francois. "PARTIAL MANTEL TESTS: REPLY TO CASTELLANO AND BALLETTO". Evolution 56, n.º 9 (septiembre de 2002): 1874–75. http://dx.doi.org/10.1111/j.0014-3820.2002.tb00204.x.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

9

Verguts, Tom y Paul Boeck. "Some Mantel-Haenszel tests of Rasch model assumptions". British Journal of Mathematical and Statistical Psychology 54, n.º 1 (mayo de 2001): 21–37. http://dx.doi.org/10.1348/000711001159401.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

10

Miller, M. P. "Computer note. MANTEL-STRUCT: a program for the detection of population structure via mantel tests". Journal of Heredity 90, n.º 1 (1 de enero de 1999): 258–59. http://dx.doi.org/10.1093/jhered/90.1.258.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

11

Cushman, Samuel, Tzeidle Wasserman, Erin Landguth y Andrew Shirk. "Re-Evaluating Causal Modeling with Mantel Tests in Landscape Genetics". Diversity 5, n.º 1 (18 de febrero de 2013): 51–72. http://dx.doi.org/10.3390/d5010051.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

12

Martín Andrés, A., I. Herranz Tejedor y M. Álvarez Hernández. "Conditional and Unconditional Tests (and Sample Size) Based on Multiple Comparisons for Stratified 2 × 2 Tables". Computational and Mathematical Methods in Medicine 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/147038.

Texto completo

Resumen

The Mantel-Haenszel test is the most frequent asymptotic test used for analyzing stratified 2×2 tables. Its exact alternative is the test of Birch, which has recently been reconsidered by Jung. Both tests have a conditional origin: Pearson’s chi-squared test and Fisher’s exact test, respectively. But both tests have the same drawback that the result of global test (the stratified test) may not be compatible with the result of individual tests (the test for each stratum). In this paper, we propose to carry out the global test using a multiple comparisons method (MC method) which does not have this disadvantage. By refining the method (MCB method) an alternative to the Mantel-Haenszel and Birch tests may be obtained. The new MC and MCB methods have the advantage that they may be applied from an unconditional view, a methodology which until now has not been applied to this problem. We also propose some sample size calculation methods.

Los estilos APA, Harvard, Vancouver, ISO, etc.

13

Rustam, Ahmad, Dali Santun Naga y Yetti Supriyati. "Sensitivity and Accuracy of the Mantel-Haenszel Method and Standardization Method: Detection of Item Functioning Differential". International Journal of Education and Literacy Studies 7, n.º 3 (31 de julio de 2019): 28. http://dx.doi.org/10.7575/aiac.ijels.v.7n.3p.28.

Texto completo

Resumen

Detection of differential item functioning (DIF) is needed in the development of tests to obtain useful items. The Mantel-Haenszel method and standardization are tools for DIF detection based on classical theory assumptions. The study was conducted to highlight the sensitivity and accuracy between the Mantel-Haenszel method and the standardization method in DIF detection. Simulation design (a) test participants consisted of 1000 responses in both the reference and focus groups, (b) the size of the proportion of DIF (0.1; 0.25; 0.50; and 0.75), and (c) the length of the multiple choice test with 40 choices the answer. Research shows that the Mantel-Haenszel method has the same sensitivity as the standardization method in DIF proportions of 10% and 25%, however, when the ratio of DIF proportions above 25% the standardization method is less sensitive, and conversely the sensitivity of the Mantel-Haenszel method increases. The standardization method has higher accuracy than the Mantel-Haenszel method in the DIF proportion of 10%, however, when the size of the DIF proportion above 10% the accuracy of the standardization method decreases, the accuracy of the Mantel-Haenszel method is higher than the standardization method. Thus, if the ratio of DIF is detected by the standardization method of (≤0.10), then the results of the standardization method are preferred as a reference. Conversely, if the proportion of DIF detected by the standardization method is (≥0.10), then the result of the Mantel-Haenszel method is chosen as a reference.

Los estilos APA, Harvard, Vancouver, ISO, etc.

14

Bowman, Michelle F., Ron Ingram, Ron A. Reid, Keith M. Somers, Norman D. Yan, Andrew M. Paterson, George E. Morgan y John M. Gunn. "Temporal and spatial concordance in community composition of phytoplankton, zooplankton, macroinvertebrate, crayfish, and fish on the Precambrian Shield". Canadian Journal of Fisheries and Aquatic Sciences 65, n.º 5 (1 de mayo de 2008): 919–32. http://dx.doi.org/10.1139/f08-034.

Texto completo

Resumen

Concordance among communities dictates how broadly we can extrapolate results derived from a set of ecosystems. We used Mantel tests to evaluate the degree of concordance in community composition among phytoplankton, zooplankton, benthic macroinvertebrate, crayfish, and fish in eight lakes near Dorset, Ontario, Canada. Spatial concordance across lakes at the decadal scale was stronger (mean Mantel r = 0.51, standard deviation (SD) = 0.20) than both intra-annual agreement (mean Mantel r = 0.38, SD = 0.20) and temporal concordance within a single lake (mean Mantel r = 0.20, SD = 0.15). The degree of temporal concordance was not related to climatic fluctuations, with the exception of increased spatial synchrony in phytoplankton communities in 1997. Strength of overall spatial concordance was most commonly related to variability in chemical attributes of the study lakes. An understanding of the determinants of concordance among taxon groups is germane to the advancement of ecology in general, as well as biodiversity conservation strategies, ecosystem monitoring, and impact diagnosis.

Los estilos APA, Harvard, Vancouver, ISO, etc.

15

Rayner, J. C. W. y D. J. Best. "Extensions to the Cochran–Mantel–Haenszel Mean Scores and Correlation Tests". Journal of Statistical Theory and Practice 12, n.º 3 (27 de febrero de 2018): 561–74. http://dx.doi.org/10.1080/15598608.2018.1439424.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

16

Beckmann, Lars, Christine Fischer y Jenny Chang-Claude. "S27.1: Accuracy of statistical tests for haplotype analysis using Mantel statistics". Biometrical Journal 46, S1 (marzo de 2004): 58. http://dx.doi.org/10.1002/bimj.200490262.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

17

Rayner, J. C. W. y G. C. Livingston. "Ordinal Cochran-Mantel-Haenszel Testing and Nonparametric Analysis of Variance: Competing Methodologies". Stats 5, n.º 4 (17 de octubre de 2022): 970–76. http://dx.doi.org/10.3390/stats5040056.

Texto completo

Resumen

The Cochran-Mantel-Haenszel (CMH) and nonparametric analysis of variance (NP ANOVA) methodologies are both sets of tests for categorical response data. The latter are competitor tests for the ordinal CMH tests in which the response variable is necessarily ordinal; the treatment variable may be either ordinal or nominal. The CMH mean score test seeks to detect mean treatment differences, while the CMH correlation test assesses ordinary or (1, 1) generalized correlation. Since the corresponding nonparametric ANOVA tests assess arbitrary univariate and bivariate moments, the ordinal CMH tests have been extended to enable a fuller comparison. The CMH tests are conditional tests, assuming that certain marginal totals in the data table are known. They have been extended to have unconditional analogues. The NP ANOVA tests are unconditional. Here, we give a brief overview of both methodologies to address the question “which methodology is preferable?”.

Los estilos APA, Harvard, Vancouver, ISO, etc.

18

Schick, R. S. y D. L. Urban. "Spatial components of bowhead whale (Balaena mysticetus) distribution in the Alaskan Beaufort Sea". Canadian Journal of Fisheries and Aquatic Sciences 57, n.º 11 (1 de noviembre de 2000): 2193–200. http://dx.doi.org/10.1139/f00-196.

Texto completo

Resumen

Bowhead whales (Balaena mysticetus) on their fall migration are exposed to oil exploration activities in the Alaskan Beaufort Sea. While previous research into the effect of industrial noise on whale behavior and distribution has noted significant responses, this research has often proceeded from a parametric statistical framework. To account for the presence of spatially autocorrelated and intercorrelated data, we propose a suite of spatial analysis techniques to assess the distribution of bowhead whales relative to oil exploration activities. Using random resampling techniques and Mantel tests, we analyzed the distribution of bowhead whales around active drilling rigs in 1993. Results from the resampling tests indicated that whales were distributed farther from the drilling rig than they would be under a random scenario. Results from the Mantel tests indicated that in 1993, the spatial pattern of bowhead whale distribution was highly correlated with distance from the drilling rig, indicating that the presence of the drilling rig resulted in a significant temporary loss in available habitat. These techniques offer a new perspective on spatial analysis in the marine realm.

Los estilos APA, Harvard, Vancouver, ISO, etc.

19

Jyväsjärvi, Jussi, Marko Järvinen y Heikki Hämäläinen. "Spatial community concordance of summer phytoplankton and profundal macroinvertebrates in boreal lakes". Canadian Journal of Fisheries and Aquatic Sciences 71, n.º 12 (diciembre de 2014): 1776–83. http://dx.doi.org/10.1139/cjfas-2014-0135.

Texto completo

Resumen

Reliance of profundal benthic macroinvertebrate assemblages on epilimnetic algal production — a key element of pelagic–benthic coupling — is a well-recognized phenomenon in the literature but the details are still poorly understood. In particular, the importance of taxonomic composition of algal communities and associated qualitative aspects of the settling material to benthic invertebrates is poorly known. We addressed this issue by investigating concordance of summer phytoplankton and profundal macroinvertebrate community composition using data from 47 boreal lakes. We examined community variation and environmental correlates of phytoplankton and macroinvertebrates with nonmetric multidimensional scaling ordinations. We also used cluster analysis to group sites according to their macroinvertebrate assemblages and evaluated the differences in phytoplankton composition and class-specific relative abundance among the clusters. Community concordance was evaluated with Procrustes rotation and partial Mantel tests, using oxygen concentration and phytoplankton biomass — the main drivers of macroinvertebrate community structure — as controlling factors. Procrustes and Mantel tests suggested congruence between macroinvertebrate and summer phytoplankton community composition. The concordance remained significant even after controlling for oxygen and biomass, by partial Mantel tests, suggesting a unique effect of phytoplankton species composition on macroinvertebrate assemblages. The four groups of lakes clustered by their macroinvertebrate assemblages also differed significantly in their phytoplankton taxa composition, and there were among-cluster differences in relative abundance of the seven most abundant phytoplankton classes. Our findings of community concordance of phytoplankton and profundal macroinvertebrates suggest a functional dependency of these two components, but further studies are needed to verify the actual causal mechanisms.

Los estilos APA, Harvard, Vancouver, ISO, etc.

20

Legendre, Pierre. "Comparison of permutation methods for the partial correlation and partial mantel tests". Journal of Statistical Computation and Simulation 67, n.º 1 (agosto de 2000): 37–73. http://dx.doi.org/10.1080/00949650008812035.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

21

Lu, Kaifeng. "Multiple imputation score tests and an application to Cochran‐Mantel‐Haenszel statistics". Statistics in Medicine 39, n.º 27 (4 de agosto de 2020): 4025–36. http://dx.doi.org/10.1002/sim.8706.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

22

Såstad, Sigurd M. "Fungi-vegetation relationships in a Pinus sylvestris forest in central Norway". Canadian Journal of Botany 73, n.º 6 (1 de junio de 1995): 807–16. http://dx.doi.org/10.1139/b95-089.

Texto completo

Resumen

The macrofungal Basidiomycete community of a Pinus sylvestris forest was investigated in 50 plots, 2 × 2 m, to see how vegetation composition and space influenced the distribution of saprotrophic and ectomycorrhizal fungi. Mantel tests and partial Mantel tests revealed a relationship between total cover of the field layer and mycorrhizal fungi, and total cover of the bottom layer and saprotrophic fungi. These results are consistent with the predictions that mycorrhizal fungi are mainly influenced by plant species present in the root zone, whereas saprotrophic fungi are mainly influenced by the plant species of the bottom layer. Variation in the abundance of tree species did not influence the distribution of macrofungal species at this scale. The spatial patterns of fungal distribution found in this study did not deviate significantly from a random distribution. Indirect ordination showed that the ectomycorrhizal fungi mainly responded to a gradient in cover of the field layer, whereas the saprotrophs seemed to respond to a complex gradient of cover of field and bottom layer, moisture, and paludification. A direct ordination using both vegetation and fungi descriptors indicated that some of the covariation in the saprotrophic fungi and the bottom layer might be coordinated responses to changes in the field layer. A considerably higher β diversity was found among the fungi than in the vegetation. Key words: basidiomycetes, saprotrophic fungi, mycorrhizal fungi, fungi–vegetation relationships, Mantel test, ordination.

Los estilos APA, Harvard, Vancouver, ISO, etc.

23

Sokołowski, Andrzej, Sabina Denkowska, Kamil Fijorek y Marcin Salamaga. "Analiza mocy wybranych testów jednorodności czasów trwania dla populacji o rozkładzie Weibulla". Przegląd Statystyczny. Statistical Review 2013, n.º 3 (30 de septiembre de 2013): 305–23. http://dx.doi.org/10.59139/ps.2013.03.2.

Texto completo

Resumen

Recently, tests for comparing survival distributions become more and more popular and used in applied economics. Unemployment duration, time needed to find a new job, enterprise survival or waiting for a commodity to be sold are good examples. There are a number of tests to compare survival distributions proposed in statistical literature. The aim of this research was to analyze, by the means of computer simulations, the effectiveness of survival tests as implemented in STATISTICA software. The following tests have been outlined and compared: Wilcoxon, Geehan, Cox-Mantel, Peto & Peto and log rank. Random samples were generated from Weibull distribution.

Los estilos APA, Harvard, Vancouver, ISO, etc.

24

Cortell-Nicolau, Alfredo, Oreto García-Puchol, María Barrera-Cruz y Daniel García-Rivero. "The spread of agriculture in Iberia through Approximate Bayesian Computation and Neolithic projectile tools". PLOS ONE 16, n.º 12 (28 de diciembre de 2021): e0261813. http://dx.doi.org/10.1371/journal.pone.0261813.

Texto completo

Resumen

In the present article we use geometric microliths (a specific type of arrowhead) and Approximate Bayesian Computation (ABC) in order to evaluate possible origin points and expansion routes for the Neolithic in the Iberian Peninsula. In order to do so, we divide the Iberian Peninsula in four areas (Ebro river, Catalan shores, Xúquer river and Guadalquivir river) and we sample the geometric microliths existing in the sites with the oldest radiocarbon dates for each zone. On this data, we perform a partial Mantel test with three matrices: geographic distance matrix, cultural distance matrix and chronological distance matrix. After this is done, we simulate a series of partial Mantel tests where we alter the chronological matrix by using an expansion model with randomised origin points, and using the distribution of the observed partial Mantel test’s results as a summary statistic within an Approximate Bayesian Computation-Sequential Monte-Carlo (ABC-SMC) algorithm framework. Our results point clearly to a Neolithic expansion route following the Northern Mediterranean, whilst the Southern Mediterranean route could also find support and should be further discussed. The most probable origin points focus on the Xúquer river area.

Los estilos APA, Harvard, Vancouver, ISO, etc.

25

Pai, Shreyas, Philip M. Polgreen, Alberto Maria Segre, Daniel K. Sewell y Sriram V. Pemmaraju. "Spatiotemporal clustering of in-hospital Clostridioides difficile infection". Infection Control & Hospital Epidemiology 41, n.º 4 (31 de enero de 2020): 418–24. http://dx.doi.org/10.1017/ice.2019.350.

Texto completo

Resumen

AbstractObjective:To determine whether Clostridioides difficile infection (CDI) exhibits spatiotemporal interaction and clustering.Design:Retrospective observational study.Setting:The University of Iowa Hospitals and Clinics.Patients:This study included 1,963 CDI cases, January 2005 through December 2011.Methods:We extracted location and time information for each case and ran the Knox, Mantel, and mean and maximum component size tests for time thresholds (T = 7, 14, and 21 days) and distance thresholds (D = 2, 3, 4, and 5 units; 1 unit = 5–6 m). All tests were implemented using Monte Carlo simulations, and random CDI cases were constructed by randomly permuting times of CDI cases 20,000 times. As a counterfactual, we repeated all tests on 790 aspiration pneumonia cases because aspiration pneumonia is a complication without environmental factors.Results:Results from the Knox test and mean component size test rejected the null hypothesis of no spatiotemporal interaction (P < .0001), for all values of T and D. Results from the Mantel test also rejected the hypothesis of no spatiotemporal interaction (P < .0003). The same tests showed no such effects for aspiration pneumonia. Our results from the maximum component size tests showed similar trends, but they were not consistently significant, possibly because CDI outbreaks attributable to the environment were relatively small.Conclusion:Our results clearly show spatiotemporal interaction and clustering among CDI cases and none whatsoever for aspiration pneumonia cases. These results strongly suggest that environmental factors play a role in the onset of some CDI cases. However, our results are not inconsistent with the possibility that many genetically unrelated CDI cases occurred during the study period.

Los estilos APA, Harvard, Vancouver, ISO, etc.

26

Tonial, MLS, HLR Silva, IJ Tonial, MC Costa, NJ Silva Júnior y JAF Diniz-Filho. "Geographical patterns and partition of turnover and richness components of beta-diversity in faunas from Tocantins river valley". Brazilian Journal of Biology 72, n.º 3 (agosto de 2012): 497–504. http://dx.doi.org/10.1590/s1519-69842012000300012.

Texto completo

Resumen

There has been a resurging interest in patterns of β-diversity, especially by the mechanisms driving broad-scale, continental and global patterns, and how partitioning β-diversity into richness (or nestedness) and turnover components can be linked with such mechanisms. Here we compared two recent methodologies to find richness and turnover components of β-diversity, using a large regional scale dataset of mammal, bird, reptiles and amphibian species found in seven regions of Central, North and Northeastern Brazil. As well as a simple comparison of the metrics available, we analyzed spatial patterns (i.e., distance-decay similarity) and the effects of biome type in these components using raw and partial Mantel tests. Our analyses revealed that turnover estimated using Baselga's (2010) approach is slightly higher than the estimate using Carvalho's et al. (2012) approach, but all analyses show consistent spatial patterns in species turnover using both methods. Spatial patterns in β-diversity revealed by Mantel tests are also consistent with expectations based on differential dispersal abilities. Our results also reinforce that spatial patterns in β-diversity, mainly in the turnover components expressing faunal differentiation, are determined by a mix or broad scale environmental effects and short distance spatially-structured dispersal.

Los estilos APA, Harvard, Vancouver, ISO, etc.

27

Lui, Kung-Jong y Kuang-Chao Chang. "Exact tests in binary data under an incomplete block crossover design". Statistical Methods in Medical Research 27, n.º 2 (21 de marzo de 2016): 579–92. http://dx.doi.org/10.1177/0962280216638382.

Texto completo

Resumen

To improve the power of a parallel groups design and reduce the time length of a crossover trial, we may consider an incomplete block crossover design. Under a distribution-free random effects logistic regression model, we derive an exact test and a Mantel-Haenszel Type of summary test procedure for testing non-equality in binary data when comparing three treatments. We employ Monte Carlo simulation to evaluate the performance of these test procedures. We find that both test procedures developed here can perform well in a variety of situations. We use the data taken as a part of the crossover trial comparing the low and high doses of an analgesic with a placebo for the relief of pain in primary dysmenorrhea to illustrate the use of the proposed test procedures.

Los estilos APA, Harvard, Vancouver, ISO, etc.

28

Leduc, A., P. Drapeau, Y. Bergeron y P. Legendre. "Study of spatial components of forest cover using partial Mantel tests and path analysis". Journal of Vegetation Science 3, n.º 1 (febrero de 1992): 69–78. http://dx.doi.org/10.2307/3236000.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

29

Gansky, Stuart A., Nancy F. Cheng y Gary G. Koch. "Dose-Weighted Adjusted Mantel-Haenszel Tests for Numeric Scaled Strata in a Randomized Trial". Statistics in Biopharmaceutical Research 3, n.º 2 (mayo de 2011): 266–75. http://dx.doi.org/10.1198/sbr.2011.10014.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

30

Pavlyuk, Dmitry. "Spatial aspects of european airports’ partial factor productivity". Transport and Telecommunication Journal 15, n.º 1 (1 de marzo de 2014): 20–26. http://dx.doi.org/10.2478/ttj-2014-0003.

Texto completo

Resumen

Abstract This research is devoted to discovering of spatial effects in European airports’ partial factor productivity (PFP). A set of study PFP indicators includes infrastructural (air transport movements per runway), labour (workload units per employee), and financial (revenue and profit per workload unit) ratios. We utilised a number of appropriate statistical tests (Moran’s I., Geary’s C., Mantel test, and spatial auto-regression) for revelation of spatial relationships between PFP indicator’s values. The tests were separately applied to samples of Spanish (2009-2010) and UK airports (2011-2012) and provided evidences of significant spatial effects in data.

Los estilos APA, Harvard, Vancouver, ISO, etc.

31

Ni, Biao, Jian You, Jiangnan Li, Yingda Du, Wei Zhao y Xia Chen. "Genetic and Epigenetic Changes during the Upward Expansion of Deyeuxia angustifolia Kom. in the Alpine Tundra of the Changbai Mountains, China". Plants 10, n.º 2 (3 de febrero de 2021): 291. http://dx.doi.org/10.3390/plants10020291.

Texto completo

Resumen

Ecological adaptation plays an important role in the process of plant expansion, and genetics and epigenetics are important in the process of plant adaptation. In this study, genetic and epigenetic analyses and soil properties were performed on D. angustifolia of 17 populations, which were selected in the tundra zone on the western slope of the Changbai Mountains. Our results showed that the levels of genetic and epigenetic diversity of D. angustifolia were relatively low, and the main variation occurred among different populations (amplified fragment length polymorphism (AFLP): 95%, methylation sensitive amplification polymorphism (MSAP): 87%). In addition, DNA methylation levels varied from 23.36% to 35.70%. Principal component analysis (PCA) results showed that soil properties of different populations were heterogeneous. Correlation analyses showed that soil moisture, pH and total nitrogen were significantly correlated with genetic diversity of D. angustifolia, and soil temperature and pH were closely related to epigenetic diversity. Simple Mantel tests and partial Mantel tests showed that genetic variation significantly correlated with habitat or geographical distance. However, the correlation between epigenetic variation and habitat or geographical distance was not significant. Our results showed that, in the case of low genetic variation and genetic diversity, epigenetic variation and DNA methylation may provide a basis for the adaptation of D. angustifolia.

Los estilos APA, Harvard, Vancouver, ISO, etc.

32

Casabianca, Jodi M. y Charles Lewis. "Statistical Equivalence Testing Approaches for Mantel–Haenszel DIF Analysis". Journal of Educational and Behavioral Statistics 43, n.º 4 (1 de diciembre de 2017): 407–39. http://dx.doi.org/10.3102/1076998617742410.

Texto completo

Resumen

The null hypothesis test used in differential item functioning (DIF) detection tests for a subgroup difference in item-level performance—if the null hypothesis of “no DIF” is rejected, the item is flagged for DIF. Conversely, an item is kept in the test form if there is insufficient evidence of DIF. We present frequentist and empirical Bayes approaches for implementing statistical equivalence testing for DIF using the Mantel–Haenszel (MH) DIF statistic. With these approaches, rejection of the null hypothesis of “DIF” allows the conclusion of statistical equivalence, a more stringent criterion for keeping items. In other words, the roles of the null and alternative hypotheses are interchanged in order to have positive evidence that the DIF of an item is small. A simulation study compares the equivalence testing approaches to the traditional MH DIF detection method with the Educational Testing Service classification system. We illustrate the methods with item response data from the 2012 Programme for International Student Assessment.

Los estilos APA, Harvard, Vancouver, ISO, etc.

33

Leuraud, K. y J. Benichou. "Tests for Monotonic Trend from Case-Control Data: Cochran-Armitage-Mantel Trend Test, Isotonic Regression and Single and Multiple Contrast Tests". Biometrical Journal 46, n.º 6 (diciembre de 2004): 731–49. http://dx.doi.org/10.1002/bimj.200210078.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

34

Rodrigues, Flávia Melo, José Alexandre Felizola Diniz-Filho, Luiz Artur Mendes Bataus y Rogério Pereira Bastos. "Hypothesis testing of genetic similarity based on RAPD data using Mantel tests and model matrices". Genetics and Molecular Biology 25, n.º 4 (2002): 435–39. http://dx.doi.org/10.1590/s1415-47572002000400013.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

35

Yanagawa, T., T. Tango y Y. Hiejima. "Mantel-Haenszel-Type Tests for Testing Equivalence or More Than Equivalence in Comparative Clinical Trials". Biometrics 50, n.º 3 (septiembre de 1994): 859. http://dx.doi.org/10.2307/2532800.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

36

Cesaroni, Donatella, Pasquale Matarazzo, Giuliana Allegrucci y Valerio Sbordoni. "Comparing patterns of geographic variation in cave crickets by combining geostatistic methods and Mantel tests". Journal of Biogeography 24, n.º 4 (julio de 1997): 419–31. http://dx.doi.org/10.1111/j.1365-2699.1997.00104.x.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

37

Donoghue, John R. y Nancy L. Allen. "Thin Versus Thick Matching in the Mantel-Haenszel Procedure for Detecting DIF". Journal of Educational Statistics 18, n.º 2 (junio de 1993): 131–54. http://dx.doi.org/10.3102/10769986018002131.

Texto completo

Resumen

This Monte Carlo study examined strategies for forming the matching variable for the Mantel-Haenszel (MH) differential item functioning (DIF) procedure; thin matching on total test score was compared to forms of thick matching, pooling levels of the matching variable. Data were generated using a three-parameter logistic (3PL) item response theory (IRT) model with common guessing parameter. Number of subjects and test length were manipulated, as were the difficulty, discrimination, and presence/absence of DIF in the studied item. Outcome measures were the transformed log-odds &Deltacirc; MH, its standard error, and the MH chi-square statistic. For short tests (5 or 10 items), thin matching yielded very poor results, with a tendency to falsely identify items as possessing DIF against the reference group. The best methods of thick matching yielded outcome measure values closer to the expected value for non-DIF items, as well as a larger value than thin matching when the studied item possessed DIF. Intermediate length tests yielded similar results for thin matching and the best methods of thick matching. The method of thick matching that performed best depended on the measure used to detect DIF. Both difficulty and discrimination of the studied item were found to have a strong effect on the value of &Deltacirc; MH.

Los estilos APA, Harvard, Vancouver, ISO, etc.

38

Silva, Daniela de M. e., Aparecido D. da Cruz, Rogério P. Bastos, Mariana P. de C. Telles y José Alexandre F. Diniz-Filho. "Morphometric and genetic differentiation among populations of Eupemphix nattereri (Amphibia, Anura, Leiuperidae) from central Brazil". Iheringia. Série Zoologia 98, n.º 4 (diciembre de 2008): 493–500. http://dx.doi.org/10.1590/s0073-47212008000400013.

Texto completo

Resumen

To assess genetic structure and phenotypic diversity of Eupemphix nattereri Steindachner, 1863, morphometric and molecular analyses were carried out for nine populations from the State of Goiás. A total of 11 morphometric traits were evaluated and genetic information was estimated using RAPD markers. Genetic and phenotypic distances were determined as a function of geographical origin. Correlation among genetic, morphometric, micro, and macroenviromental were analyzed by the Mantel test. Genetic data indicated high levels of genetic diversity (Φst= 0.3) among the nine populations. Mantel tests did not reveal a significant positive correlation between genetic and geographical distances, indicating that locally geographical populations were not genetically similar, even in distances smaller than 50 km. Discriminant analysis on 11 morphometric measurements showed a high divergence among the nine populations. However, a marginally significant correlation (P=0.08) between genetic and morphometric distances was found. The observed correlation was not causal in terms of the relationship between phenotype and genotype, but indicated common spatial structures. Thus, our results suggest that isolation-by-distance processes may explain population divergence in Eupemphix nattereri.

Los estilos APA, Harvard, Vancouver, ISO, etc.

39

Burgman, Mark A. "An analysis of the distribution of plants on granite outcrops in southern Western Australia using Mantel tests". Vegetatio 71, n.º 2 (agosto de 1987): 79–86. http://dx.doi.org/10.1007/bf00044821.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

40

Velásquez-Zapata, Valeria, Katherine Palacio-Rúa, Luz E. Cano y Adelaida Gaviria-Rivera. "Assessment of genotyping markers in the molecular characterization of a population of clinical isolates of Fusarium in Colombia". Biomédica 42, n.º 1 (1 de marzo de 2022): 18–30. http://dx.doi.org/10.7705/biomedica.5869.

Texto completo

Resumen

Introduction: Fusarium is a very heterogeneous group of fungi, difficult to classify, with a wide range of living styles, acting as saprophytes, parasites of plants, or pathogens for humans and animals. Prevalence of clinical fusariosis and lack of effective treatments have increased the interest in the precise diagnosis, which implies a molecular characterization of Fusarium populations.Objective: We compared different genotyping markers in their assessment of the genetic variability and molecular identification of clinical isolates of Fusarium.Materials and methods: We evaluated the performance of the fingerprinting produced by two random primers: M13, which amplifies a minisatellite sequence, and (GACA)4, which corresponds to a simple repetitive DNA sequence. Using the Hunter Gaston Discriminatory Index (HGDI), an analysis of molecular variance (AMOVA), and a Mantel test, the resolution of these markers was compared to the reference sequencing-based and PCR genotyping methods.Results: The highest HGDI value was associated with the M13 marker followed by (GACA)4. AMOVA and the Mantel tests supported a strong correlation between the M13 classification and the reference method given by the partial sequencing of the transcription elongation factor 1-alpha (TEF1-α) and rDNA 28S.Conclusion: The strong correlation between the M13 classification and the sequencingbased reference together with its higher resolution demonstrates its adequacy for the characterization of Fusarium populations.

Los estilos APA, Harvard, Vancouver, ISO, etc.

41

Romano, Vito Antonio, Leonardo Rosati, Simonetta Fascetti, Anna Maria Roberta Cittadini, Rocco Racioppi, Richard Lorenz y Maurizio D’Auria. "Spatial and Temporal Variability of the Floral Scent Emitted by Barlia robertiana (Loisel.) Greuter, a Mediterranean Food-Deceptive Orchid". Compounds 2, n.º 1 (27 de enero de 2022): 37–53. http://dx.doi.org/10.3390/compounds2010004.

Texto completo

Resumen

This study on Barlia robertiana aims to: (1) assess whether scent is variable between populations; (2) evaluate whether scent composition may be related to geographical variables; (3) assess whether there are VOC differences during the flowering phase; and (4) assess whether there are yearly VOC variabilities. SPME sampling was used. Fourteen plants, collected along an ecological gradient, were analyzed. A multivariate analysis was performed through ordination and hierarchical cluster analysis. Compositions versus geographic distances were also analyzed using Mantel test. Seventy compounds were identified. Multivariate analyses and Mantel tests detected no correlations between VOC composition and both geographic and ecological variables. These results may suggest that there is no adaptation of floral scent to local environments. VOC compositions during the flowering phase showed a slight change but a strong variability between individuals. A huge difference was found in the pairwise comparison of the plants analyzed in different years. The high scent variability can be interpreted as a strategy of a non-rewarding but allogamous species to not allow the learning by pollinators. In fact, disrupting the association among floral scent signals with the lack of nectar may enhance the fruit set via a higher probability of being visited by insects.

Los estilos APA, Harvard, Vancouver, ISO, etc.

42

Ibrahim, Abdul Wahab. "The Applicability of Item Response Theory Based Statistics to Detect Differential Item Functioning in Polytomous Tests". Randwick International of Education and Linguistics Science Journal 1, n.º 1 (23 de junio de 2020): 1–13. http://dx.doi.org/10.47175/rielsj.v1i1.23.

Texto completo

Resumen

The study used statistical procedures based on Item Response Theory to detect Differential Item Functioning (DIF) in polytomous tests. These were with a view to improving the quality of test items construction. The sample consisted of an intact class of 513 Part 3 undergraduate students who registered for the course EDU 304: Tests and Measurement at Sule Lamido University during 2017/2018 Second Semester. A self-developed polytomous research instrument was used to collect data. Data collected were analysed using Generalized Mantel Haenszel, Simultaneous Item Bias Test, and Logistic Discriminant Function Analysis. The results showed that there was no significant relationship between the proportions of test items that function differentially in the polytomous test when the different statistical methods are used. Further, the three parametric and non-parametric methods complement each other in their ability to detect DIF in the polytomous test format as all of them have capacity to detect DIF but perform differently. The study concluded that there was a high degree of correspondence between the three procedures in their ability to detect DIF in polytomous tests. It was recommended that test experts and developers should consider using procedure based on Item Response Theory in DIF detection.

Los estilos APA, Harvard, Vancouver, ISO, etc.

43

Dias, Filipe S., Michael Betancourt, Patricia María Rodríguez-González y Luís Borda-de-Água. "BetaBayes—A Bayesian Approach for Comparing Ecological Communities". Diversity 14, n.º 10 (11 de octubre de 2022): 858. http://dx.doi.org/10.3390/d14100858.

Texto completo

Resumen

Ecological communities change because of both natural and human factors. Distinguishing between the two is critical to ecology and conservation science. One of the most common approaches for modelling species composition changes is calculating beta diversity indices and then relating index changes to environmental changes. The main difficulty with these analyses is that beta diversity indices are paired comparisons, which means indices calculated with the same community are not independent. Mantel tests and generalised dissimilarity modelling (GDM) are two of the most commonly used statistical procedures for analysing such data, employing randomisation tests to consider the data’s dependence. Here, we introduce a Bayesian model-based approach called BetaBayes that explicitly incorporates the data dependence. This approach is based on the Bradley–Terry model, which is a widely used approach for modelling paired comparisons that involves building a standard regression model containing two varying intercepts, one for each community involved in the beta diversity index, that capture their respective contributions. We used BetaBayes to analyse a famous dataset collected in Panama that contains information on multiple 1 ha plots from the rain forests of Panama. We calculated the Bray–Curtis index between all pairs of plots, analysed the relationship between the index and two covariates (geographic distance and elevation), and compared the results of BetaBayes with those from the Mantel test and GDM. BetaBayes has two distinctive features. The first is its flexibility, which allows the user to quickly change it to fit the data structure; namely, by adding varying effects, incorporating spatial autocorrelation, and modelling complex nonlinear relationships. The second is that it provides a clear path for performing model validation and model improvement. BetaBayes avoids hypothesis testing, instead focusing on recreating the data generating process and quantifying all the model configurations that are consistent with the observed data.

Los estilos APA, Harvard, Vancouver, ISO, etc.

44

Casado-López, Irene, Yale Tung-Chen, Marta Torres-Arrese, Davide Luordo-Tedesco, Arantzazu Mata-Martínez, Jose Manuel Casas-Rojo, Esther Montero-Hernández y Gonzalo García De Casasola-Sánchez. "Usefulness of Multi-Organ Point-of-Care Ultrasound as a Complement to the Decision-Making Process in Internal Medicine". Journal of Clinical Medicine 11, n.º 8 (18 de abril de 2022): 2256. http://dx.doi.org/10.3390/jcm11082256.

Texto completo

Resumen

Accumulated data show the utility of diagnostic multi-organ point-of-care ultrasound (PoCUS) in the assessment of patients admitted to an internal medicine ward. We assessed whether multi-organ PoCUS (lung, cardiac, and abdomen) provides relevant diagnostic and/or therapeutic information in patients admitted for any reason to an internal medicine ward. We conducted a prospective, observational, and single-center study, at a secondary hospital. Multi-organ PoCUS was performed during the first 24 h of admission. The sonographer had access to the patients’ medical history, physical examination, and basic complementary tests performed in the Emergency Department (laboratory, X-ray, electrocardiogram). We considered a relevant ultrasound finding if it implied a significant diagnostic and/or therapeutic change. In the second semester of 2019, we enrolled 310 patients, 48.7% were male and the mean age was 70.5 years. Relevant ultrasound findings were detected in 86 patients (27.7%) and in 60 (19.3%) triggered a therapeutic change. These findings were associated with an older age (Mantel–Haenszel χ2 = 25.6; p < 0.001) and higher degree of dependency (Mantel–Haenszel χ2 = 5.7; p = 0.017). Multi-organ PoCUS provides relevant diagnostic information, complementing traditional physical examination, and facilitates therapy adjustment, regardless of the cause of admission. Multi-organ PoCUS to be useful need to be systematically integrated into the decision-making process in internal medicine.

Los estilos APA, Harvard, Vancouver, ISO, etc.

45

Uttaro, Thomas. "Influences on the Mantel-Haenszel Chi-Square in Detection of Differential Item Functioning under Rasch Conditions". Perceptual and Motor Skills 80, n.º 3_suppl (junio de 1995): 1071–74. http://dx.doi.org/10.2466/pms.1995.80.3c.1071.

Texto completo

Resumen

The Mantel-Haenszel chi-square (χ2MH) is widely used to detect differential item functioning (item bias) between ethnic and gender-based subgroups on educational and psychological tests. The empirical behavior of χ2MH has been incompletely understood; previous research is inconclusive. The present simulation study explored the effects of sample size, number of items, and trait distributions on the power of χ2MH to detect modeled differential item functioning. A significant effect was obtained for sample size with unacceptably low power for 250 subjects each in the focal and reference groups. The discussion supports the 1990 recommendations of Swaminathan and Rogers, opposes the 1993 view of Zieky that a sample size of 250 for each group is adequate.

Los estilos APA, Harvard, Vancouver, ISO, etc.

46

., Sukemi. "ANALYSIS OF DIFFERENTIAL ITEM FUNCTION (DIF) COATS-Haenszel USING DIFFERENT AREAS UNDER THE TOWN AND VILLAGE IN NATIONAL TEST DEVICE IN BANTEN IPA SD ( Primary School)". JISAE: Journal of Indonesian Student Assessment and Evaluation 3, n.º 1 (27 de febrero de 2017): 45–61. http://dx.doi.org/10.21009/jisae.v3i1.4860.

Texto completo

Resumen

Analysis of Differential Item Function (DIF) / otherness Function Item is an analysis conducted on a set of tests to determine the bias point. Bias grains occur because of differences in background of respondents test, while a good test devices have qualities of objectivity, transparency, accountability and non-discriminatory. This study aimed to describe the test items were contracted Differential Item Function (DIF) at the National Examination IPA SD devices based on differences in urban and rural areas in the province of Banten using Mantel-Haenszel statistical methods. Mantel Haenszel method is a statistical method that belong to the classical theory to estimate the capability (ability) answered correctly and one of the two groups Referring (City group) and Focus (village groups). In the analysis of the National Examination tests conducted by IPA SD urban and rural areas because basically learning science provide insights into the learners to study the nature of life in a real and every region has a characteristic difference in the character of each. Learners tendency of characters to characters who occupied a very large area of influence, so that the DIF analysis was performed on the test device by city and village. The method used in this research is descriptive quantitative method based on the translation of factual data and systematically based on numerical analysis using statistics, with a population of primary school learners based on the classification of the city of Dan Village. Selection of the sample was done by using stratified random sampling by classifying and analyzing each unit of analysis. Data is collected using secondary data from relevant agencies and government agencies manually and online. The analysis carried out quantitative analysis using the Mantel-Haenszel method. The results of the analysis indicate that there Differential Item Function (DIF) on items of National Examination test devices based on the analysis of urban and rural differences. DIF infected grain on the test device, twelve grains of forty grains, with a tendency to point to areas of the city of five items and the tendency to rural areas totaled seven points. Data is collected using secondary data from relevant agencies and government agencies manually and online. The analysis carried out quantitative analysis using the Mantel-Haenszel method. The results of the analysis indicate that there Differential Item Function (DIF) on items of National Examination test devices based on the analysis of urban and rural differences. DIF infected grain on the test device, twelve grains of forty grains, with a tendency to point to areas of the city of five items and the tendency to rural areas totaled seven points. Data is collected using secondary data from relevant agencies and government agencies manually and online. The analysis carried out quantitative analysis using the Mantel-Haenszel method. The results of the analysis indicate that there Differential Item Function (DIF) on items of National Examination test devices based on the analysis of urban and rural differences. DIF infected grain on the test device, twelve grains of forty grains, with a tendency to point to areas of the city of five items and the tendency to rural areas totaled seven points. The results of the analysis indicate that there Differential Item Function (DIF) on items of National Examination test devices based on the analysis of urban and rural differences. DIF infected grain on the test device, twelve grains of forty grains, with a tendency to point to areas of the city of five items and the tendency to rural areas totaled seven points. The results of the analysis indicate that there Differential Item Function (DIF) on items of National Examination test devices based on the analysis of urban and rural differences. DIF infected grain on the test device, twelve grains of forty grains, with a tendency to point to areas of the city of five items and the tendency to rural areas totaled seven points.

Los estilos APA, Harvard, Vancouver, ISO, etc.

47

., Sukemi. "ANALYSIS OF DIFFERENTIAL ITEM FUNCTION (DIF) COATS-Haenszel USING DIFFERENT AREAS UNDER THE TOWN AND VILLAGE IN NATIONAL TEST DEVICE IN BANTEN IPA SD ( Primary School)". JISAE: JOURNAL OF INDONESIAN STUDENT ASSESMENT AND EVALUATION 3, n.º 1 (27 de febrero de 2017): 45–61. http://dx.doi.org/10.21009/jisae.031.05.

Texto completo

Resumen

Analysis of Differential Item Function (DIF) / otherness Function Item is an analysis conducted on a set of tests to determine the bias point. Bias grains occur because of differences in background of respondents test, while a good test devices have qualities of objectivity, transparency, accountability and non-discriminatory. This study aimed to describe the test items were contracted Differential Item Function (DIF) at the National Examination IPA SD devices based on differences in urban and rural areas in the province of Banten using Mantel-Haenszel statistical methods. Mantel Haenszel method is a statistical method that belong to the classical theory to estimate the capability (ability) answered correctly and one of the two groups Referring (City group) and Focus (village groups). In the analysis of the National Examination tests conducted by IPA SD urban and rural areas because basically learning science provide insights into the learners to study the nature of life in a real and every region has a characteristic difference in the character of each. Learners tendency of characters to characters who occupied a very large area of influence, so that the DIF analysis was performed on the test device by city and village. The method used in this research is descriptive quantitative method based on the translation of factual data and systematically based on numerical analysis using statistics, with a population of primary school learners based on the classification of the city of Dan Village. Selection of the sample was done by using stratified random sampling by classifying and analyzing each unit of analysis. Data is collected using secondary data from relevant agencies and government agencies manually and online. The analysis carried out quantitative analysis using the Mantel-Haenszel method. The results of the analysis indicate that there Differential Item Function (DIF) on items of National Examination test devices based on the analysis of urban and rural differences. DIF infected grain on the test device, twelve grains of forty grains, with a tendency to point to areas of the city of five items and the tendency to rural areas totaled seven points. Data is collected using secondary data from relevant agencies and government agencies manually and online. The analysis carried out quantitative analysis using the Mantel-Haenszel method. The results of the analysis indicate that there Differential Item Function (DIF) on items of National Examination test devices based on the analysis of urban and rural differences. DIF infected grain on the test device, twelve grains of forty grains, with a tendency to point to areas of the city of five items and the tendency to rural areas totaled seven points. Data is collected using secondary data from relevant agencies and government agencies manually and online. The analysis carried out quantitative analysis using the Mantel-Haenszel method. The results of the analysis indicate that there Differential Item Function (DIF) on items of National Examination test devices based on the analysis of urban and rural differences. DIF infected grain on the test device, twelve grains of forty grains, with a tendency to point to areas of the city of five items and the tendency to rural areas totaled seven points. The results of the analysis indicate that there Differential Item Function (DIF) on items of National Examination test devices based on the analysis of urban and rural differences. DIF infected grain on the test device, twelve grains of forty grains, with a tendency to point to areas of the city of five items and the tendency to rural areas totaled seven points. The results of the analysis indicate that there Differential Item Function (DIF) on items of National Examination test devices based on the analysis of urban and rural differences. DIF infected grain on the test device, twelve grains of forty grains, with a tendency to point to areas of the city of five items and the tendency to rural areas totaled seven points.

Los estilos APA, Harvard, Vancouver, ISO, etc.

48

Hardy, Olivier J. y Sandrine Pavoine. "ASSESSING PHYLOGENETIC SIGNAL WITH MEASUREMENT ERROR: A COMPARISON OF MANTEL TESTS, BLOMBERG ET AL.'S K, AND PHYLOGENETIC DISTOGRAMS". Evolution 66, n.º 8 (9 de abril de 2012): 2614–21. http://dx.doi.org/10.1111/j.1558-5646.2012.01623.x.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

49

Yu, Liguo. "Using Kolmogorov Complexity to Study the Coevolution of Header Files and Source Files of C-alike Programs". International Journal of Knowledge and Systems Science 8, n.º 2 (abril de 2017): 17–26. http://dx.doi.org/10.4018/ijkss.2017040102.

Texto completo

Resumen

In C-alike programs, the source code is separated into header files and source files. During the software evolution process, both these two kinds of files need to adapt to changing requirement and changing environment. This paper studies the coevolution of header files and source files of C-alike programs. Using normalized compression distance that is derived from Kolmogorov complexity, we measure the header file difference and source file difference between versions of an evolving software product. Header files distance and source files distance are compared to understand their difference in pace of evolution. Mantel tests are performed to investigate the correlation of header file evolution and source file evolution. The study is performed on the source code of Apache HTTP web server.

Los estilos APA, Harvard, Vancouver, ISO, etc.

50

de Almeida Vieira, Fábio, Cristiane Gouvêa Fajardo, Anderson Marcos de Souza y Dulcinéia de Carvalho. "Landscape-Level and Fine-Scale Genetic Structure of the Neotropical TreeProtium spruceanum(Burseraceae)". International Journal of Forestry Research 2010 (2010): 1–8. http://dx.doi.org/10.1155/2010/120979.

Texto completo

Resumen

Knowledge of genetic structure at different scales and correlation with the current landscape is fundamental for evaluating the importance of evolutionary processes and identifying conservation units. Here, we used allozyme loci to examine the spatial genetic structure (SGS) of 230 individuals ofProtium spruceanum, a native canopy-emergent in five fragments of Brazilian Atlantic forest (1 to 11.8 ha), and four ecological corridors (460 to 1 000 m length). Wright's statistic and Mantel tests revealed little evidence of significant genetic structure at the landscape-scale (; , ). At fine-scale SGS, low levels of relatedness within fragments and corridors (, ) were observed. Differences in the levels and distribution of the SGS at both spatial scales are discussed in relation to biological and conservation strategies of corridors and forest fragments.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Artículos de revistas sobre el tema "Tests de Mantel"

Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros