Changes In Sex Ratio Research Articles

The change of sex ratio in Lamprey based on predator and Logistic model

This paper studies the sex ratio and resource availability of lamprey population, through the predator model and Logistic model of lamprey population dynamic simulation. Differential equations were used to dynamically describe the dynamic changes within lampreys population, and then the effects of changes in sex ratio on the food chain, population reproduction rate, habitat occupation and resource availability were analyzed. Optimize and analyze the population dynamic change model to simulate the impact of changing sex ratio on the population. Based on the competition and mutualism between lampreys and parasites, combined with the food chain in which they are located, the ecological model of multi-species interaction is re-established on the basis of the original model to solve the problem, and the sensitivity analysis of the final result is carried out.We found that changes in the sex ratio of lampreys populations can provide an advantage to other species.

Changes in seasonality and sex ratio of scrub typhus: a case study of South Korea from 2003 to 2019 based on wavelet transform analysis

BackgroundScrub typhus (ST, also known as tsutsugamushi disease) is a common febrile vector-borne disease in South Korea and commonly known as autumn- and female-dominant disease. Although understanding changes in seasonality and sex differences in ST is essential for preparing health interventions, previous studies have not dealt with variations in periodicity and demographic characteristics in detail. Therefore, we aimed to quantify the temporal dynamics of seasonal patterns and sex differences in the incidence of ST in South Korea.MethodsWe extracted epidemiological week (epi-week)-based ST cases from 2003 to 2019 Korean National Health Insurance Service data (ICD-10-CM code: A75.3). To determine changes in seasonality and sex differences, year-, sex-, and age-group-stratified male-to-female ratios and wavelet transform analyses were conducted.ResultsBetween 2003 and 2019, 213,976 ST cases were identified. The incidence per 100,000 population increased by 408.8% from 9.1 in 2003 to 37.2 in 2012, and subsequently decreased by 59.7% from 2012 to 15.0 in 2019. According to the continuous wavelet transform results, ST exhibited a dual seasonal pattern with dominant seasonality in autumn and smaller seasonality in spring from 2005 to 2019. Overall, the periodicity of seasonality decreased, whereas its strength decreased in autumn and increased in spring. With an overall male-to-female ratio being 0.68:1, the ratio has increased from 0.67:1 in 2003 to 0.78:1 in 2019 (Kendall’s τ = 0.706, p < 0.001). However, interestingly, the ratio varied significantly across different age groups.ConclusionsOur findings quantitatively demonstrated changes in seasonality with dual seasonal pattern and shortened overall periodicity and a decrease in sex differences of ST in South Korea. Our study suggests the need for continuous surveillance on populations of vector and host to address ST dynamics to preemptively prepare against global warming.

Research on the Impact of Sex Ratio Changes on the Population Dynamics of Lamprey Based on the Lotka-Volterra Algorithm

Research on the Impact of Sex Ratio Changes on the Population Dynamics of Lamprey Based on the Lotka-Volterra Algorithm

Effects of sex ratio changes in Lampreys on ecosystem based on modeling techniques

Effects of sex ratio changes in Lampreys on ecosystem based on modeling techniques

An ecological population study of lampreys in the Lotka-Volterra tertiary trophic level based on sex differences

This study examines the adaptive changes in sex ratio on animal populations and its effects on ecosystem stability and interactions. The effects of sex ratio dynamics on the ecosystem were analyzed through mathematical modeling using lampreys as the study population. In this study, a two-stage tertiary trophic Lotka-Volterra mathematical model of ecological dynamics was developed, taking into account food preferences, ecological roles, and sex interactions of lampreys. The simulation results showed that a rapid adjustment in sex ratio led to a reduction in environmental loads, which triggered an early rebound increase in lampreys and predator populations. To assess the ability of lampreys populations to adjust sex ratios, this study used a combination of fuzzy integrated evaluation and hierarchical analysis methods. The results of the study revealed the importance of sex-adaptive traits for population development, including increased resource utilization efficiency and population fitness, as well as decreased reproductive success and reduced genetic diversity. Based on the RRT (resistance, resilience and temporal stability) method, this study constructed an ecosystem stability assessment model and investigated the effects of changes in the sex ratio of lampreys on ecosystem stability. The experimental results showed that ecosystem stability was highest when the sex ratio was 0.6 and lowest when the sex ratio was 0.2. Variation in sex ratio may affect the behavior and abundance of lampreys, thereby directly influencing their interactions with other species. Variability in sex ratio provides more resources for predators and parasites of lampreys, promotes their growth, and positively affects ecosystem balance. Simulation results showed that the model was highly stable under different interactions. In summary, this study reveals the important effects of sex ratio on ecosystem stability and interactions, and provides important insights into the understanding of adaptive evolutionary traits of species, ecosystem stability and ecological interactions.

Sociodemographic Trends and Perinatal Outcomes in Fathers 50 Years and Older

The age of fathers at childbirth is rising, with an increasing number of births attributed to older fathers. While the impact of advanced paternal age has been documented, sociodemographic data about fathers aged 50 years and older remain scarce. To explore sociodemographic and temporal trends among the oldest US fathers (age ≥50 years) and their associations with perinatal outcomes. This retrospective cross-sectional study included data from all US births from 2011 to 2022 using the National Vital Statistics System. Data were analyzed from August 2023 and May 2024. Reported paternal age at childbirth. Outcomes of interest were sociodemographic factors, temporal trends in older fatherhood, and perinatal outcomes, including preterm birth, low birth weight, gestational diabetes, gestational hypertension, assisted reproductive technology (ART), rates of maternal primiparity, and the infant sex ratio. From 2011 to 2022, the US recorded 46 195 453 births, with an overall mean (SD) paternal age of 31.5 (6.8) years and 484 507 (1.1%) involving fathers aged 50 years or older, 47 785 (0.1%) aged 60 years or older, and 3777 (0.008%) aged 70 years or older. Births to fathers aged 50 years or older increased from 1.1% in 2011 to 1.3% in 2022 (P for trend < .001). Fathers aged 50 years or older were more diverse, with variations in educational achievement and race and ethnicity. Marital status and maternal racial and ethnic and educational backgrounds also varied by paternal age and race. Despite controlling for maternal age and other sociodemographic and perinatal factors, every 10-year increase in paternal age was consistently associated with greater use of ART (eg, age 50-59 years: adjusted odds ratio [aOR], 2.23; 95% CI, 2.19-2.27), higher likelihood of first maternal birth (eg, age 50-59 years: aOR, 1.16; 95% CI, 1.15-1.17), and increased risks of preterm birth (eg, age 50-59 years: aOR, 1.16; 95% CI, 1.15-1.18) and low birth weight (eg, age 50-59 years: aOR, 1.14; 95% CI, 1.13-1.15) compared with fathers aged 30 to 39 years. No significant changes in the infant sex ratio were observed, except among fathers aged 70 years or older (aOR, 0.92; 95% CI, 0.86-0.99) and 75 years or older (aOR, 0.84; 95% CI, 0.73-0.97), who showed a decreased likelihood of having male offspring. In this cross-sectional study of all US births from 2011 to 2022, the percentage attributed to older fathers, while small, increased. Notable variations in paternal and maternal race and education were identified. Older fatherhood was associated with increased ART use, first-time maternal births, adverse perinatal outcomes, and altered sex ratio. Further research of this population is crucial for improving patient counseling and family planning.

Study on the Impact of Sex Ratio Changes in Lamprey on the Ecosystem and Its Stability

Study on the Impact of Sex Ratio Changes in Lamprey on the Ecosystem and Its Stability

Effects of changes in lamprey sex ratios on ecosystem stability: a Lotka-Volterra model-based study

Effects of changes in lamprey sex ratios on ecosystem stability: a Lotka-Volterra model-based study

Discussion on the effect of sex ratio change in lamprey

Objective: To study the impact of the change of sex ratio of lamprey on the whole ecosystem, and to provide guidance for the stability of the ecosystem, the conservation of species diversity, and the green and sustainable development of the ecological environment in the future. Methods: In the first step, the logistic regression model was used to study the population dynamics of lamprey from the aspects of birth rate, mortality rate, food source rate and dependent population, and the impact of sex ratio change on the ecosystem was observed. In the second step, the impact of sex ratio change on the stability of the whole ecosystem was studied through the adjoint model. In the third step, the logistic regression model was used to construct a differential equation describing female and male lamp eels in different environments to distinguish the different sexes of lampreys. In the fourth step, an ecological dynamics model was established that comprehensively considered factors such as intermediate hosts, biological subpopulations, environmental conditions, and self-competition to fully understand the impact of changes in the sex ratio of lampreys on ecosystem stability. Finally, the sensitivity analysis of the model was carried out, and the model was evaluated and expanded. Results: A model was established to affect the population dynamics of lamprey, the gender differentiation of lamprey and the influence of lamprey on ecosystem stability. Conclusion: It was found that changes in the sex ratio of lamprey populations would affect their own reproduction rate and population size, the survival and reproduction patterns of other species, and the stability of the whole ecosystem.

Effects Of Changes in Adaptive Sex Ratios on Biome Dynamics: Based on Lotka-Volterra Modeling

Effects Of Changes in Adaptive Sex Ratios on Biome Dynamics: Based on Lotka-Volterra Modeling

A study of sex ratio in lampreys based on Lotka-Volterra modelsour Paper's Title Starts Here: Please Center

To elucidate the interactions between changes in adaptive sex ratios of lampreys and ecosystems, we conducted the following studies; first, we used linear regression to fit the relationship between food availability and sex ratios. Based on vortex modeling and biological knowledge, we simulated three scenarios: natural disasters, species invasions, and data from similar species in normal ecosystems. This led to the modeling of lamprey population growth. To further investigate the effect of sex ratio changes on ecosystem stability, we built an n-dimensional Lotka-Volterra model. Combining the relationship between food supply and sex ratio, we identified the mechanisms by which sex ratio affects ecosystem stability.

Our Plants as Doctors in Today’s Animal Health

Svante Arrhenius, Swedish scientist predicted as early as 1896 that human activity would interfere with the way sun interferes with the earth- leading to global warming, climatic change and loss of biodiversity. Environmental change has affected most biological systems on our planet, mostly negatively. This is becoming an increased concern for the well-being and survival of many species. The effect of environment encompasses endocrine disruptions, sex ratio changes and decreased reproductive parameters, also include physiological, genotoxic, tetrogenic, immune suppressing effect, that lead to disease directly or increase of acquiring disease. Utilization of plants has been in vogue from time immemorial for various needs. Plants with medicinal properties enjoy the highest considerations in indigenous systems of medicine. Knowledge of the curative properties of specific plants is an accomplished art which is passed on from one generation to the next. Healthy animals are more likely to result in safer food supplies, higher production, reduced environmental impacts, improved animal well-being and most importantly reduced use of antibiotics. Plants are nature’s doctors, so plants when used for correction of animal health problems, reduce the disease management expenditure by nearly 40%. More plant utilization with re cropping will bring down the negative impacts of the environmental issues. Very easily available neighbourhood wild plants happen to be solutions for great health problems of animals. Utilization of this plant treasure can work the wonder wand for a better environment free of Global environment concerns.

Sex Ratio of Seven Gill Eels Based on System Dynamics and Dynamic Generalisation Models

This paper provides an in-depth study of the ecological impacts of changing sex ratios in the lampreys, an ancient species known as a living fossil, through mathematical modeling. First, a dynamic model was constructed to simulate the response of the sex ratio of the lampreys to food availability and to predict subsequent changes in predator populations within the ecosystem. The model also considered reproductive success to assess broader ecological impacts. The results suggest that changes in lampreys sex ratio can significantly affect ecosystems in many ways. However, risks such as overfishing, environmental stress and predation emerged as clear disadvantages. Further exploration through more advanced dynamic modeling confirmed the stabilizing effect of higher male ratios on the ecosystem. The study also ventured into competition modeling, revealing that lamprey populations may inadvertently favor other species, such as parasites. Taken together, the mathematical modeling in this study provides insights into the ecological role of lampreys and is intended to inform conservation efforts and optimize the ecological use of lampreys.

Modeling and analysis of ecosystem dynamics based on the Lotka-Volterra model

In this paper, the ecological dynamics of sea lamprey populations were explored using the Lotka-Volterra model. Its ecosystem dynamics were also modeled. The analysis showed that changes in the sex ratio of sea lampreys can lead to a decrease in the abundance of other species within a certain range. Thus, changes in sex ratio affect the abundance of other species in the larger ecosystem. In addition, the study assessed the strengths and weaknesses associated with sea lamprey populations through iterative modeling. Six advantages (growth rate, environmental adaptation, importance in the food chain, ecosystem contribution, predation control, and reproductive efficiency) and four disadvantages (environmental stress, risk of overfishing, threats to reproduction, and threats to predation) were assessed in terms of population stability, reproductive fitness, and ecological impact. The results showed that when sex ratios were equal, the greatest advantage was predation control and the greatest disadvantage was overfishing risk. When males were dominant, the greatest advantage was adaptability, while the greatest disadvantage was predation threat.

Study on the Gender Change of the Lamprey in Ecosystem Based on Verhulst and Logistic Models

This paper focuses on the environmental impacts of changes in the sex ratio of the lampreys, the assessment of the strengths and weaknesses of lamprey’s adaptations, and their effects on ecosystem stability. In this paper, we first considered Verhulst and Logistic models of ecosystem-sex-ratio interactions, and predicted and analyzed the potential cascading effects of changes in lampreys sex ratio on larger ecosystems under different scenarios. Then, by integrating the Logistic model, we simulated the development and change of the ecosystem under various conditions, identified assessment metrics, and evaluated the relative strengths and weaknesses of the lampreys. The research in this paper provides important evidence for a deeper understanding of the role of the lampreys in ecosystems and the effects of changes in their sex ratio.

Changes of sex ratio at birth and son preferences in China: a mixed method study

In 2020, China’s sex ratio at birth (SRB) stood at 111.3, still exhibiting a notable bias. Son preference ranks as the most essential and fundamental reason for the skewed SRB. This study, using a mixed-methods approach, seeks to address what the temporal changes and regional differences in SRB and the gender preferences are in China, whether and why son preference persists, how people practice such preferences and how they relate to the persistently high SRB in the Chinese context. Analysis of data from five national sample surveys finds that son preference is waning and daughter preference is gaining momentum, consistent with significant downward trends in SRB. The study also reveals that value shifts and intergenerational relations have a strong influence on gender preferences and their translation into reproductive behavior. Additionally, this study highlights the challenges that are hindering the decline in son preference, suggesting that more efforts are needed to empower women and to change social norms.

Changes in the adult sex ratio of six duck species breeding populations over two decades

Despite all efforts, long-term changes in the adult sex ratios of breeding duck populations are still unclear; this uncertainty is especially true for male-bias populations, which are often under the scrutiny of researchers lacking convenient results for the active protection of endangered species. Species with male-bias populations are usually strongly affected by a decline in population size that leads to a higher extinction risk. In this study, we examined our long-term data of the abundance of breeding populations in six duck species (Mallard Anas platyrhynchos, Gadwall Mareca strepera, Red-crested Pochard Netta rufina, Common Pochard Aythya ferina, Tufted Duck Aythya fuligula, and Common Goldeneye Bucephala clangula) from fishponds in South Bohemia, Czechia, between 2004 and 2022. This evidence was used to assess long-term changes in the adult sex ratio in these breeding populations and investigate the possible effects of the NAO index (North Atlantic Oscillation index) on them, indicating climate conditions in winter. We determined a long-term decrease of the proportion of females in the breeding season in two of the six examined species: Common Pochard and Red-crested Pochard, which is driven by the long-term increase in the number of males in contrast to the decreasing or stable number of females likely caused by different migration behaviours between females and males. In the case of Common Pochard, in breeding populations, we estimated 60–65% of males in the early 2000s rising to 75–80% in the early 2020s. However, we establish no significant effects linked to climate conditions of the previous winter in these species as a crucial cause of the changes of the proportion of females in the breeding population.

Two World Wars and Belgium: Missing Births and Birth Sex Ratio Changes.

The sex ratio at birth (male/total births, M/T) is expected to approximate 0.515. M/T is influenced by many factors including stress. Both World Wars have been implicated as influencing birth rates and M/T. This study was carried out to analyse the effects of two World Wars on Belgium vis-à-vis missing births as well as M/T changes. Belgian male and female births were available for 1830-2019 and annual population was available from Statista. ARIMA models were used to estimate and project birth losses. The effect of wars was assumed to begin in the years following the commencement of each war and extend to the year after cessation of hostilities i.e., 1915-1919 and 1940-1946 for the First and Second World Wars respectively. This study included 27,346,178 live births for 1830-2019, M/T 0.5124. There was a decreasing trend in births for 1830-2019, significant for 1950-2019. There were dips in births in association with both Wars resulting in over 440,000 missing births, 3.80% of the Belgian population for the First World War and 1.91% for the Second World War. M/T rose non-significantly for the First World War and significantly for the Second World War. The declining birth rate and M/T in developed countries is a recognised phenomenon. The missing births in relation to wars are of demographic importance but are often overlooked with emphasis usually on casualties and deaths. M/T may rise in wars, possibly due to increased coital activity as well as other factors.

基于Lotka-Volterra种群动态模型的水生动物性别比例变化研究

基于Lotka-Volterra种群动态模型的水生动物性别比例变化研究

Effect of Ficus carica leaves Aqueous Crud Extract on the Number of Wild Fruit Flies and Sperm Morphology of Laboratory Albino Male Mice

The purpose of this study was to compare the effects of two concentrations of aqueous crude extract from Ficus carica leaves on fruit fly numbers, sex ratios, and generations, as well as laboratory albino mouse sperm abnormalities. Fruit flies were given the concentrations of 1% marked as C1 and 2% marked as C2 in culture media and allowed to complete their life cycle at an acceptable temperature (25o C±2) in an incubator. Same concentrations were given to the tested mice in drinking water. Each treatment consisted of five replications, with untreated mice and flies serving as the control groups. Fruit fly findings were seen in the first and second generations, and mouse sperm morphology was examined one month following treatment. The results revealed that tested concentrations had no significant impact (P≤0.05) on the quantity of fruit flies mean values were (40.650 ± 2.40 5and 39.250 ± 2.624) froe first and second concentrations compared to 34.550 ± 2.12 in control group, but they did have a significant impact (P≤0.05) on the sex ratio (shifted toward females (40.733 ± 1.969) in comparison to males (35.566 ± 1.838), least significant differences(L.S.D.) were = 5.148, and generation-concentration interactions, the highest number were recorded was females in second generation (42.900 ± 2.203). The treated mice showed Significant effect of concentrations on sperm without tail and highly significant effect (P≤0.01) on sperm without hook (mean values were 5.6 ± 0.37 and 2.0 ± 0.44 in high concentration while in control group the values were 2.0 ± 0.44 and1.0 ± 0.44) for both aberrations respectively. Our results clearly indicated change in sex ratio among treated fruit flies and induction of some morphologic changes in mice sperms after treatment of fig leaves aqueous crud extract.