Level Of Theory Research Articles

Revisiting Horizontal Stratification in Higher Education: College Prestige Hierarchy and Educational Assortative Mating in China.

Existing research on assortative mating has examined marriage between people with different levels of education, yet heterogeneity in educational assortative mating outcomes of college graduates has been mostly ignored. Using data from the 2010 Chinese Family Panel Study and log-multiplicative models, this study examines the changing structure and association of husbands' and wives' educational attainment between 1980 and 2010, a period in which Chinese higher education experienced rapid expansion and stratification. Results show that the graduates of first-tier institutions are less likely than graduates of lower-ranked colleges to marry someone without a college degree. Moreover, from 1980 to 2010, female first-tier-college graduates were increasingly more likely to marry people who graduated from similarly prestigious colleges, although there is insufficient evidence to draw the same conclusion about their male counterparts. This study thus demonstrates the extent of heterogeneity in educational assortative mating patterns among college graduates and the tendency for elite college graduates to marry within the educational elite.

What Tears Couples Apart: A Machine Learning Analysis of Union Dissolution in Germany.

This study contributes to the literature on union dissolution by adopting a machine learning (ML) approach, specifically Random Survival Forests (RSF). We used RSF to analyze data on 2,038 married or cohabiting couples who participated in the German Socio-Economic Panel Survey, and found that RSF had considerably better predictive accuracy than conventional regression models. The man's and the woman's life satisfaction and the woman's percentage of housework were the most important predictors of union dissolution; several other variables (e.g., woman's working hours, being married) also showed substantial predictive power. RSF was able to detect complex patterns of association, and some predictors examined in previous studies showed marginal or null predictive power. Finally, while we found that some personality traits were strongly predictive of union dissolution, no interactions between those traits were evident, possibly reflecting assortative mating by personality traits. From a methodological point of view, the study demonstrates the potential benefits of ML techniques for the analysis of union dissolution and for demographic research in general. Key features of ML include the ability to handle a large number of predictors, the automatic detection of nonlinearities and nonadditivities between predictors and the outcome, generally superior predictive accuracy, and robustness against multicollinearity.

A review of 263 years of taxonomic research on Hypoplectrus (Perciformes: Serranidae), with a redescription of Hypoplectrus affinis (Poey, 1861).

The hamlets (Hypoplectrus spp., Perciformes: Serranidae) constitute a distinctive model system for the study of a variety of ecological and evolutionary processes including the evolution and maintenance of simultaneous hermaphroditism and egg trading, sex allocation, sexual selection, social-trap, mimicry, dispersal, speciation, and adaptive radiation. Addressing such fundamental and complex processes requires a good knowledge of the taxonomy and natural history of the hamlets. Here, we review the taxonomy of the hamlets, from early ichthyological studies to the most recent species description in 2018. We report a total of 72 different binomial names for Hypoplectrus, synonymized or invalidated down to 17 unambiguously recognized species today. In addition, we redescribe Hypoplectrus affinis (Poey, 1861) as a valid species. In Bocas del Toro (Panama), this hamlet is distinct from eight sympatric congeners in terms of colour pattern, body size and behaviour. Whole-genome analysis and spawning observations indicate that it is genetically distinct from sympatric congeners and reproductively isolated through assortative pairing. Based on the colour pattern we detail in its redescription, live-fish photographs, videos, and earlier reports, H. affinis occurs in Panama, Nicaragua, Mexico, the Florida Keys, Cuba, Grand Cayman, Jamaica, the Dominican Republic, Los Roques (Venezuela), Bonaire, and Tobago. We conclude with a discussion of pending taxonomic issues in this group and the species status of the hamlets in general.

Mate Selection Behavior of GED Recipients

The General Educational Development (GED) degree is designed to be a credential equivalent to the high school diploma. However, growing evidence indicates that GED recipients have worse outcomes than high school graduates. Such findings raise the question: is the GED socially equivalent to the high school diploma? Although educational assortative mating patterns have long been used as a barometer of the social distance across educational groups, there has not been a study that has addressed this question by examining the marital sorting patterns of GED recipients. Using log-linear models, our study shows that the odds of intermarriage between GED recipients and high school graduates resemble those between GED recipients and those without a secondary degree. Racial/ethnic minorities had greater difficulty crossing the GED/high school graduate boundary when they married. Our findings detract from the purported view that the GED degree is equivalent to a traditional high school diploma.

Sexual dichromatism and assortative mating by multiple plumage color traits in wild Chestnut Thrush

Sex differences in plumage color are common in bird species. Some bird species are regarded as sexually monochromatic in human visual systems, and in recent years, some species are found to be of cryptic (to human) sexual dichromatism by spectrophotometric techniques. However, the functions of plumage color are still less understood in these species. Here, we focused on plumage color traits in the Chestnut Thrush (Turdus rubrocanus), which is considered as a sexually monochromatic bird by human observers. We used spectrometer analyses and avian visual modeling to investigate the color traits of males and females, and whether these color traits are involved in assortative mating. We found that Chestnut Thrush showed sexual dichromatism in bill, throat and wing, and pairs mated assortatively with colorations of throat, chest, crown and wing. We also found that color of tarsus was different between two consecutive years. These results revealed that Chestnut Thrush is sexually dichromatic in the avian visual system, and plumage color traits play important roles in mate choice.

Similarity in Indicators of Attractiveness in Heterosexual Couples, and their Relationship with Satisfaction and Trust

In our species, the formation and maintenance of romantic partners is a nonrandom process. In this sense, similarity between members of the couple can be relevant for the beginning of the relationship (i.e., assortative mating) and maintenance, being similarity in attractiveness one of the most interesting aspects of this phenomenon. Despite that similarity in attractive traits has been documented, there is a lack of studies including modern morphological measures like fluctuating facial asymmetry or body fat percentage when assessing the effect that similarity in attractiveness could provoke on behaviors and feelings necessary to maintain a long-term relationship (e.g., satisfaction and trust). We assessed the presence of similarity in attractiveness for self-perceived measures (attractiveness and mate value) and physical traits (body fat percentage, body mass index, and fluctuating facial asymmetry) in a population of 196 heterosexual young couples from Chile (n = 392). Then, using actor-partner interdependence models (APIM), we assessed whether satisfaction and trust within the couples were influenced by attractiveness. Our results indicated the presence of similarity for all studied traits with the exception of fluctuating facial asymmetry. In addition, we only found that self-assessment of attractiveness is important for satisfaction in women, and partner's physical attractiveness is important for satisfaction and trust in men. Our results suggest that similarity in attractiveness is not playing a major role in affecting relationship. It is probably that similarity could be better explained from the initial stages of relationship, where the mating market forces conduce to the conformation of similar couples.

Assortative Mating and Wealth Inequality

Assortative Mating and Wealth Inequality

Cultural evolution may influence heritability by shaping assortative mating.

Uchiyama et al. productively discuss how culture can influence genetic heritability and, by modifying environmental conditions, limit the generalizability of genome-wide association studies (GWASs). Here, we supplement their account by highlighting how recent changes in culture and institutions in industrialized, westernized societies - such as increased female workforce participation - may have increased assortative mating. This alters the distribution of genotypes themselves, increasing heritability and phenotypic variance, and may be detectable using the latest methods.

A Thiomidazolylborate based Carbon Paste Electrode for Voltametric Detection of Heavy Metals in Wastewater

The ligand potassium hydrotris(N- (2,6-xylyl)-2-thioimidazolyl)borate (KTtxylyl) was utilized to construct a carbon paste modified electrode (KTtxylyl/CPE), which was studied using electrochemical impedance spectroscopy, cyclic voltammetry and square wave voltammetry (SWV). Its electrochemical response was investigated, and it demonstrated a significant improvement in the detection of both lead(II) and cadmium(II), allowing determination of lead(II) at trace concentrations. The spectroscopic evidence includes FT-IR, Raman, 1H NMR and also DFT calculations using B3LYP/LANL2DZ level of theory indicate the high affinities of these ions toward the ligand forming lead(II) and cadmium complexes of the type [TtxylylMCl]. Negative electrostatic potential of the tri(thione) donors deriving their binding abilities toward both ions. The detection limits based on 3(SD/m) were; 0.112 μM and 0.204 μM for lead(II) and cadmium(II), respectively. The simultaneous detection of these ions in several waste water samples was examined in order to verify the modified electrode. Data from the ICP-AES instrument was compared to the results obtained.

Antimony(III) Dithiocarbamates: Synthesis, Spectral, Theoretical and Biological Activities

Antimony(III) dithiocarbamate complexes tris(N,N-difurfuryldithiocarbamato-S,S′)antimony(III) (1) and tris(N-furfuryl-N-(2-phenylethyl)dithiocarbamato-S,S′)antimony(III) (2) have been synthesized and characterized by CHN analysis, FT-IR, 1H NMR, 13C NMR spectra and antimicrobial studies. The characteristic thioureide ν(C-N) bands occur at 1459 and 1469 cm-1 for complexes 1 and 2, respectively. 1H NMR and 13C NMR chemical shifts have been calculated using GIAO approach and the calculated chemical shifts shows good agreement with experiential shifts. The computational calculations of the antimony(III) complexes have been carried out by DFT/B3LYP using LANL2DZ basis set. The FMOs, MEP, Mulliken charge distribution and chemical activity parameters were calculated at the same level of theory. The antimicrobial activities of the antimony(III) complexes were assayed at the concentrations 400 and 800 μg/mL against four bacterial (Vibrio cholera, Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli) and two fungal species (Candida albicans and Aspergillus niger) by Agar-well disc diffusion method.

Fumiya Uchikoshi and James M. Raymo, “Educational Assortative Mating in Japan: Insights into Social Change and Stratification” Springer Briefs in Population Studies, Singapore: Springer, 2021, xix+124p

Fumiya Uchikoshi and James M. Raymo, “Educational Assortative Mating in Japan: Insights into Social Change and Stratification” Springer Briefs in Population Studies, Singapore: Springer, 2021, xix+124p

Strong assortative mating in ninespine stickleback Pungitius tymensis demonstrated in no-choice mating trials between pairs of three congeneric species

Strong assortative mating in ninespine stickleback <i>Pungitius tymensis</i> demonstrated in no-choice mating trials between pairs of three congeneric species

Sexual dimorphism and sex-differential migration of Little Buntings (Emberiza pusilla) at an East Asian stopover site

Sex differences in morphology provide key information for understanding a species' morphological adaptations in relation to the evolution of sexual selection. In migratory birds, morphological traits have adapted to long-distance travel, and sexual dimorphism is typically related to sex-differential migration phenology. Little Buntings (Emberiza pusilla) have one of the longest migrations and are the least dichromatic species among the Emberiza buntings. In this study, we measured sexual size dimorphism and sexual dichromatism of Little Buntings in relation to the spring arrival dates at a stopover site in Korea. Wing length was the most important predictor for identifying sex; the wings of males were longer than those of females. Males also had a significantly stronger chestnut color of the head feathers than females, but this color difference was more prominent in the spring than in the fall. Males arrived earlier than females by four days. Arrival dates correlated with both size and color, but unlike other bunting species previously studied in the same area, there was no clear sex-differential trend in the relationship between arrival date and morphological characteristics. Seasonal differences in the degree of sexual dichromatism suggest that chestnut plumage coloration can be used as a social or sexual signal of males in the breeding season. The correlation of size and color to early arrival regardless of sex may indicate that a preference for assortative mating exists or that a sex-differential migration strategy is not clearly defined in the early stages of northward migration. Our findings on the sexual dimorphism of Little Buntings provide insight into the evolution of the sex-differential migration of buntings in the East Asian Flyway.

Spousal Concordance of Cardiovascular Risk Factors in Newly Married Couples in China

Several studies have shown that older married couples share a propensity for accruing the same cardiovascular risk factors such as hypertension and dyslipidemia. However, it remains unclear if these spousal associations reflect their shared home environment and lifestyle or the tendency to choose a partner with a similar perspective on lifestyle choices and behaviors (assortative mating). Evaluating these associations in young, newly married couples may help to differentiate between these 2 possibilities. To evaluate the spousal concordance of cardiovascular risk factors in young, newly married couples. This prospective cohort study recruited 831 couples around the time of marriage registration in Liuyang, China, from February 1, 2009, to November 4, 2015. Statistical analysis was performed from April to May 2021. Spousal concordance of cardiovascular risk factors. Both partners underwent systematic assessment of cardiovascular risk factors, including evaluation of anthropometrics, blood pressure, and fasting lipids. Among the 831 participating couples, mean (SD) age was 24 (3) years in the women and 26 (4) years in the men. There were significant correlations between spouses in systolic blood pressure (r = 0.43; P < .001), diastolic blood pressure (r = 0.36; P < .001), total cholesterol (r = 0.13; P < .001), low-density lipoprotein cholesterol (r = 0.11; P = .003), high-density lipoprotein (HDL) cholesterol (r = 0.22, P < .001), and triglycerides (r = 0.13; P = .001). After adjustment for covariates (age, household income, education level, smoking, and either body mass index or waist circumference), significant correlations persisted between spouses in their systolic blood pressure (r = 0.42; P < .001), diastolic blood pressure (r = 0.34; P < .001), HDL cholesterol (r = 0.17; P < .001), and triglycerides (r = 0.10; P = .04). This cohort study found spousal concordance of cardiovascular risk factors among young newly married couples. Assortative mating based on these concordant risk factors at the time of marriage may partially explain the shared vascular risk profile of older marital partners and raises the possibility of couple-based care.

Evaluating the legacy of multiple introductions of American martens on spatiotemporal patterns of genetic diversity

AbstractSpecies reintroductions are successful when established populations maintain both demographic stability and genetic diversity. Such a result may be obtained by ensuring both structural habitat connectivity and genetic connectivity among reintroduced and remnant populations. Nevertheless, prezygotic barriers such as assortative mating can prevent the flow of genetic material between populations, even when migration between populations is high. Limited gene flow may be particularly relevant for reintroductions that were sourced either from captive-bred populations or from disparate locations in the wild. American martens (Martes americana) have been reintroduced repeatedly in the Upper Midwestern United States in an effort to establish self-sustaining populations. We quantified levels of genetic diversity within and spatial genetic variance among four marten populations during two time periods separated by 10 years. Spatially informed and naïve discriminant analysis of principal components were used to assign individuals to populations. Results indicate that heterozygosity declined and inbreeding coefficients increased between the two collection periods, while genetic structure among populations also increased. Data are consistent with assortative mating contributing to reapportioning of genetic variation. Population assignment tests show that migration among populations is apparent, but admixture (based on cluster membership probabilities) is low and declined over time. Specifically, martens may be successfully dispersing between populations but a lack of admixture indicates a lack of reproductive contributions to genetic diversity by migrants. Because marten reintroductions in this region are well-documented and well-monitored, lessons can be derived from results to inform future reintroductions. We encourage a careful balance of supplementing genetic diversity via augmentation while avoiding translocation of animals from disparate populations that may result in reproductive isolation of migrants. In combination with the maintenance of a functionally connected landscape, this strategy would maximize the likelihood of a successful reintroduction in terms both of demography and genetics.

Exploration of Risk Factors for Cognitive Decline Shared by Couples and Cognitive Outcomes—Assortative Mating, Lifestyle, and Chronic Stress

Exploration of Risk Factors for Cognitive Decline Shared by Couples and Cognitive Outcomes—Assortative Mating, Lifestyle, and Chronic Stress

Dating on your level: assortative mating based on body condition in an amphibian

In animal mating systems, individuals obtain fitness benefits by selecting a mate that increases their chance of reproductive success. Among amphibians, it is generally considered that females select males, primarily based on advertisement calls that signal their size, quality or compatibility. Yet, it is becoming increasingly apparent that amphibians exhibit a wide range of mating systems, including those where assortative mating can occur. Herein, we investigated mate selection in the sandpaper frog, Lechriodus fletcheri; an Australian anuran that breeds explosively during discrete periods of rainfall over an extended breeding period. We compared the size and condition of amplecting pairs relative to other potential suitors within the available population of reproductively active adults over 3 consecutive breeding years. We found no relationship between the SVL of amplecting pairs and no effect of SVL on amplecting status of males within pools. Instead, the condition of amplecting pairs was positively correlated, leading to positive assortative mating. While there was a general decline in condition of adult males and females across each season, changes in the temporal availability of better conditioned mates does not account for the assortative mating were found. Males found in amplexus were also generally of poorer condition, which may occur as individuals investing more heavily into higher-signalling effort are more successful in finding a mate but at the expense of maintaining current condition. We propose that both findings could be evidence of active mate choice in an explosive breeding species. Our findings highlight the need to consider mate condition alongside size to detect the presence of assortative mating or non-random mating among explosive breeding amphibians.

Age‐related breeding success in little penguins: a result of selection and ontogenetic changes in foraging and phenology

AbstractReproductive performance typically improves with age, reaching a plateau at middle age and subsequently declining in older age classes (senescing individuals). Three potential non‐exclusive mechanisms can explain the improvement in reproductive performance with age: (1) selection (poor quality individuals are removed from the population with increasing age), (2) constraint (individual efficiency increases through experience), and (3) restraint (reproductive investment increases with age as the residual reproductive value decreases). While all three mechanisms received strong empirical support, few studies have aimed at teasing apart those hypotheses and understanding their underlying functioning. In little penguins (Eudyptula minor), we used a 19‐yr longitudinal dataset on breeding and foraging of more than 450 individuals to investigate the effect of age on breeding success. We separated within‐individual from among‐individual age effects using state‐of‐the‐art statistical methods (within‐subject centering and population change decomposition). We then assessed whether within‐individual changes in breeding resulted from ontogenetic changes in foraging performances, breeding phenology or access to mates and nest sites. Fidelity and assortative pairing explained the high correlation in male and female ages within a pair. Breeding performances followed a typical bell‐shaped curve with performance increasing up to 8 yr old, before reaching a plateau and subsequently declining after age 16. Both selection and within‐individual processes occurred, although within‐individual changes dominated differences in age‐dependent breeding success. The selective appearance had almost no effect (apart from ages 2–3), and selective disappearance mostly affected changes at old ages (above 16), although they were also responsible for the slight increase in reproductive performances from ages 5–8. Focusing on within‐individual changes, birds exhibited higher performances at middle ages, with birds foraging better, laying earlier and changing partner and nest less often. Their reproductive investment did not vary with age for females and slightly decreased for males. This supports the constraint hypothesis but not the restraint one. Finally, the increase in breeding performances at young ages was explained by the age‐related increase in foraging performances during chick‐rearing and advancement of laying. In contrast, reproductive senescence was defined by a general decrease in bird performances.

Assortative Mating Among College Graduates: Heterogeneity Across Fields of Study

Advancing prior research that treated college graduates as a homogeneous group, we investigate heterogeneity in assortative mating patterns across baccalaureate degree fields. As baccalaureate degree fields are related to occupation, an important question remains about whether field-of-study homogamy begets occupational homogamy. We drew on the school-to-work transition literature, which shows that baccalaureate degree fields differ in their linkages to a targeted or diffuse set of occupational destinations. We analyzed 34,373 college-educated newlyweds from the 2009–2019 American Community Surveys. Log-linear analysis revealed a tendency for college graduates, especially those in vocational specific fields (fields that have targeted connections to specific occupations; e.g., law, health, and education), to marry a spouse in the same field. In addition, occupational homogamy was more likely to occur among couples with two spouses in the same vocational specific field than among couples with two spouses in different fields. By examining patterns and implications of field-of-study assortative mating, this study underlines the importance of horizontal stratification of higher education in shaping meeting opportunities and highlights how pathways from field of study to occupation structure marriage markets.

Estimation of the strength of mate preference from mated pairs observed in the wild.

A number of key processes in evolution are driven by individuals preferring mates with particular phenotypes. However, despite long‐standing interest, it is difficult to quantify the strength of mate preference from phenotypic observations in nature in a way that connects directly to key parameters in theoretical models. To bridge the gap between mathematical models and empirical data, we develop a novel maximum likelihood‐based method to estimate the strength and form of mate preference, where preference depends on traits expressed in both males and females. Using simulated data, we demonstrate that our method accurately infers model parameters, including the strength of mate preference and the optimal offset match between trait values in mated pairs when model assumptions are satisfied. Applying our method to two previous studies of assortative mating in marine gastropods and the European common frog, we support previous findings, but also give additional insight into the role of mate preference in each system. Our method can be generalized to a variety of plant and animal taxa that exhibit mating preferences to facilitate the testing of evolutionary hypotheses and link empirical data to theoretical models of assortative mating, sexual selection, and speciation.