Structured Demes and Trait-Group Variation

1979 ◽  
Vol 113 (4) ◽  
pp. 606-610 ◽  
Author(s):  
David Sloan Wilson
Keyword(s):  
Group Variation ◽  
Structured Demes ◽  
Trait Group

scholarly journals Robust Inferences from a Before-and-After Study with Multiple Unaffected Control Groups

2013 ◽  
Vol 1 (2) ◽  
pp. 209-234 ◽  
Author(s):  
Pengyuan Wang ◽  
Mikhail Traskin ◽  
Dylan S. Small
Keyword(s):  
Sensitivity Analysis ◽  
Control Groups ◽  
Two Stage ◽  
Time Effects ◽  
Unaffected Control ◽  
Group Time ◽  
Before And After ◽  
Group Variation ◽  
The Impact ◽  
Before And After Study

AbstractThe before-and-after study with multiple unaffected control groups is widely applied to study treatment effects. The current methods usually assume that the control groups’ differences between the before and after periods, i.e. the group time effects, follow a normal distribution. However, there is usually no strong a priori evidence for the normality assumption, and there are not enough control groups to check the assumption. We propose to use a flexible skew-t distribution family to model group time effects, and consider a range of plausible skew-t distributions. Based on the skew-t distribution assumption, we propose a robust-t method to guarantee nominal significance level under a wide range of skew-t distributions, and hence make the inference robust to misspecification of the distribution of group time effects. We also propose a two-stage approach, which has lower power compared to the robust-t method, but provides an opportunity to conduct sensitivity analysis. Hence, the overall method of analysis is to use the robust-t method to test for the overall hypothesized range of shapes of group variation; if the test fails to reject, use the two-stage method to conduct a sensitivity analysis to see if there is a subset of group variation parameters for which we can be confident that there is a treatment effect. We apply the proposed methods to two datasets. One dataset is from the Current Population Survey (CPS) to study the impact of the Mariel Boatlift on Miami unemployment rates between 1979 and 1982.The other dataset contains the student enrollment and grade repeating data in West Germany in the 1960s with which we study the impact of the short school year in 1966–1967 on grade repeating rates.

Further Insights on Fake-Barn Cases and Intuition Variation

Episteme ◽  
2021 ◽  
pp. 1-18
Author(s):  
Carsten Bergenholtz ◽  
Jacob Busch ◽  
Sara Kier Praëm
Keyword(s):  
Experimental Philosophy ◽  
Thought Experiment ◽  
Thought Experiments ◽  
Risk Attitude ◽  
Knowledge Ascription ◽  
Underlying Factor ◽  
Demographic Group ◽  
Knowledge Ascriptions ◽  
Group Variation ◽  
Fake Barn

Abstract Studies in experimental philosophy claim to document intuition variation. Some studies focus on demographic group-variation; Colaço et al., for example, claim that age generates intuition variation regarding knowledge attribution in a fake-barn scenario. Other studies claim to show intuition variation when comparing the intuition of philosophers to that of non-philosophers. The main focus has been on documenting intuition variation rather than uncovering what underlying factor(s) may prompt such a phenomenon. We explore a number of suggested explanatory hypotheses put forth by Colaço et al., as well as an attempt to test Sosa's claim that intuition variance is a result of people ‘filling in the details’ of a thought experiment differently from one another. We show (i) that people respond consistently across conditions aimed at ‘filling in the details’ of thought experiments, (ii) that risk attitude does not seem relevant to knowledge ascription, (iii) that people's knowledge ascriptions do not vary due to views about defeasibility of knowledge. Yet, (iv) we find no grounds to reject that a large proportion of people appear to adhere to so-called subjectivism about knowledge, which may explain why they generally have intuitions about the fake-barn scenario that vary from those of philosophers.

scholarly journals Feed demand behavior in sea bass juveniles: Effects on individual specific growth rate variation and health (inter-individual and inter-group variation)

Aquaculture ◽  
2008 ◽  
Vol 274 (1) ◽  
pp. 87-95 ◽  
Author(s):  
S. Millot ◽  
M.-L. Bégout ◽  
J. Person-Le Ruyet ◽  
G. Breuil ◽  
C. Di-Poï ◽  
...  
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Sea Bass ◽  
Rate Variation ◽  
Group Variation

A comparison of variation of Pseudotsuga menziesii seedlings from genetically defined and undefined sources

1989 ◽  
Vol 67 (3) ◽  
pp. 945-947 ◽  
Author(s):  
Jack Maze ◽  
Satindranath Banerjee
Keyword(s):  
Pseudotsuga Menziesii ◽  
Genetic Background ◽  
Complex Mixture ◽  
Growing Season ◽  
Population Variation ◽  
Mixed Genetic Background ◽  
Diverse Background ◽  
Group Variation ◽  
Sib Families

Leader lengths were compared for seedlings (i) from full-sib families and (ii) of mixed genetic background 12 times over their second growing season. We wished to examine whether the variation in genetically defined groups was equal to, or less than, that from a genetically diverse background. Aside from one time, there was no difference in within-group variation for full-sib seedlings and for those of mixed genetic background. When variation was not equal, it was one of the full-sib families that was the most variable. This indicates that the high within-population variation in Pseudotsuga menziesii reflects crossing between highly variable individuals and not a complex mixture of half-sib families.

scholarly journals The biological effect of cage design corrected for reductions in spray penetration

2014 ◽  
Vol 54 (4) ◽  
pp. 395-400 ◽  
Author(s):  
Bradley Keith Fritz ◽  
Wesley Clint Hoffmann ◽  
Jane Annalise Sara Bonds ◽  
Keith Haas ◽  
Zbigniew Czaczyk
Keyword(s):  
Wind Tunnel ◽  
Biological Effect ◽  
Conversion Factor ◽  
Mortality Data ◽  
Data Set ◽  
Spray Penetration ◽  
Mosquito Mortality ◽  
Insect Mortality ◽  
Group Variation ◽  
Penetration Data

Abstract In-field measures of physical spray concentration do not tend to correlate well with caged insect mortality data. This is partly due to the reduced penetration of the spray into the cage. Spray penetration is hindered by the structure of the cage. Wind tunnel studies were conducted to investigate the accuracy of those calculations developed to correct for filtration levels in caged mosquito bioassays. Zenivex E20 (Etofenprox) was applied at rates ranging from an LD10 to an LD90. Three cage types were used, each with different penetration levels. The dose approaching the cage was converted to the dose entering the cage using cage penetration data from previous research. The penetration conversion factor returned a data set that directly correlated dose with mosquito mortality (R2 = = 0.918). The mortality percent was a function of the dose within the cage. The mesh type acted as a regulator. Although the conversion factor was effective, the differences between cages was not always significant due to within-group variation.

scholarly journals Erythraeid larvae parasitizing dragonflies in Zambia—description of Leptus (Leptus) chingombensis sp. nov. with data on biology and ecology of host-parasite interactions

2019 ◽  
Vol 24 (5) ◽  
pp. 790
Author(s):  
Rafał Bernard ◽  
Magdalena Felska ◽  
Joanna Mąkol
Keyword(s):  
Dna Barcode ◽  
Morphological Characteristics ◽  
Parasite Load ◽  
Ventral Side ◽  
Habitat Conditions ◽  
Local Character ◽  
Host Parasite Interactions ◽  
Group Variation ◽  
The Common ◽  
Host Parasite

A survey of odonate fauna in Zambia (Central Province, Luano District) resulted in discovery of ectoparasitic larvae of Leptus (L.) chingombensis sp. nov. (Trombidiformes: Parasitengona, Erythraeidae) on four species of dragonflies (Odonata) representing four different families assigned to Zygoptera and Anisoptera. The morphological characteristics of the new species is supported with DNA barcode sequence. Despite some intra-group variation related to relatively large sample, the morphological and genetic consistence confirm the common specific identity of the material. A brief comparison of Leptus spp. hitherto known from the Afrotropic as larvae is given. Supplementary data to the descriptions of Leptus (L.) bicristatus Fain et Elsen, 1987, Leptus (L.) aldonae Haitlinger, 1987 and Leptus (L.) soddagus Haitlinger, 1990, based on examination of type material, are provided. In the case of L. (L.) chingombensis sp. nov., the parasite load reached high, previously not recorded for Odonata–terrestrial Parasitengona association values, attaining at 44 and 49 larvae. Clear topic preferences towards the ventral side of the host’s body were recorded, with an additional tendency to distal parts of synthorax and the ventral depression of the abdomen. We hypothesize that the infestation did not take place synchronously at dragonflies emergence, but consisted in repeated infestation events during the recurrent appearance of dragonflies in the contact microhabitat occupied by Leptus. The very local character of the finding along with the regular appearance of larvae parasitizing dragonflies, obviously favoured by specific habitat conditions, no doubts confirms the non-accidental nature of the phenomenon.

scholarly journals The role of matrilineality in shaping patterns of Y chromosome and mtDNA sequence variation in southwestern Angola

2018 ◽  
Author(s):  
Sandra Oliveira ◽  
Alexander Hübner ◽  
Anne-Maria Fehn ◽  
Teresa Aço ◽  
Fernanda Lages ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Sequence Data ◽  
Population History ◽  
Female Population ◽  
Bantu Languages ◽  
Mtdna Sequence ◽  
Population Sizes ◽  
Group Variation ◽  
History Of ◽  
Previous Demonstration

AbstractSouthwestern Angola is a region characterized by contact between indigenous foragers and incoming food-producers, involving genetic and cultural exchanges between peoples speaking Kx’a, Khoe-Kwadi and Bantu languages. Although present-day Bantu-speakers share a patrilocal residence pattern and matrilineal principle of clan and group membership, a highly stratified social setting divides dominant pastoralists from marginalized groups that subsist on alternative strategies and have previously been though to have pre-Bantu origins. Here, we compare new high-resolution sequence data from 2.3 Mb of the non-recombining Y chromosome (NRY) from 170 individuals with previously reported mitochondrial genomes (mtDNA), to investigate the population history of seven representative southwestern Angolan groups (Himba, Kuvale, Kwisi, Kwepe, Twa, Tjimba, !Xun) and to study the causes and consequences of sex-biased processes in their genetic variation. We found no clear link between the formerly Kwadi-speaking Kwepe and pre-Bantu eastern African migrants, and no pre-Bantu NRY lineages among Bantu-speaking groups, except for small amounts of “Khoisan” introgression. We therefore propose that irrespective of their subsistence strategies, all Bantu-speaking groups of the area share a male Bantu origin. Additionally, we show that in Bantu-speaking groups, the levels of among-group and between-group variation are higher for mtDNA than for NRY. These results, together with our previous demonstration that the matriclanic systems of southwestern Angolan Bantu groups are genealogically consistent, suggest that matrilineality strongly enhances both female population sizes and interpopulation mtDNA variation.

Do differences matter? A typology of emerging adult romantic relationship

2016 ◽  
Vol 34 (3) ◽  
pp. 334-355 ◽  
Author(s):  
Patricia N. E. Roberson ◽  
Jerika Christine Norona ◽  
Jessica N. Fish ◽  
Spencer B. Olmstead ◽  
Frank Fincham
Keyword(s):  
College Students ◽  
Romantic Relationships ◽  
Emerging Adults ◽  
Romantic Relationship ◽  
Latent Class ◽  
Emerging Adult ◽  
Predictor Variables ◽  
Future Research ◽  
Latent Class Analyses ◽  
Group Variation

Romantic relationships among emerging adults (individuals aged 18–25 years) are typically homogenously classified both theoretically and empirically as “exploratory” and “unstable.” With a sample of college students ( N = 340), we examined within-group variation among romantic relationships in emerging adulthood using latent class analyses. Four predictor variables indicated four types of romantic relationships among emerging adult college students: the committers (38%), the casual daters (23%), the settlers (30%), and the volatile daters (8%). Classes varied according to background variables such as gender and infidelity. Additionally, there was class variation for outcome variables such as breakup status and loneliness. Future research and implications are discussed.

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