scholarly journals More Women Missing, Fewer Girls Dying: The Impact of Abortion on Sex Ratios at Birth and Excess Female Mortality in Taiwan

2008 ◽  
Author(s):  
Ming-Jen Lin ◽  
Nancy Qian ◽  
Jin-Tan Liu
2021 ◽  
pp. 140349482110100
Author(s):  
Ralph Catalano

Aims: To determine whether differences between Norway’s and Sweden’s attempts to contain SARS-CoV-2 infection coincided with detectably different changes in their all-cause mortality sex ratios. Measuring temporal variation in the all-cause mortality sex ratio before and during the pandemic in populations exposed to different constraints on risky behavior would allow us to better anticipate changes in the ratio and to better understand its association with infection control strategies. Methods: I apply time Box–Jenkins modeling to 262 months of pre-pandemic mortality sex ratios to arrive at counterfactual values of 10 intra-pandemic ratios. I compare counterfactual to observed values to determine if intra-pandemic ratios differed detectably from those expected as well as whether the Norwegian and Swedish differences varied from each other. Results: The male to female mortality sex ratio in both Norway and Sweden increased during the pandemic. I, however, find no evidence that the increase differed between the two countries despite their different COVID-19 containment strategies. Conclusion: Societal expectations of who will die during the COVID-19 pandemic will likely be wrong if they assume pre-pandemic mortality sex ratios because the intra-pandemic ratios appear, at least in Norway and Sweden, detectably higher. The contribution of differences in policies to reduce risky behavior to those higher ratios appears, however, small.


Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1169-1180 ◽  
Author(s):  
Daven C Presgraves ◽  
Emily Severance ◽  
Gerald S Willrinson

Meiotically driven sex chromosomes can quickly spread to fixation and cause population extinction unless balanced by selection or suppressed by genetic modifiers. We report results of genetic analyses that demonstrate that extreme female-biased sex ratios in two sister species of stalk-eyed flies, Cyrtodiopsis dalmanni and C. whitei, are due to a meiotic drive element on the X chromosome (Xd). Relatively high frequencies of Xd in C. dalmanni and C. whitei (13–17% and 29%, respectively) cause female-biased sex ratios in natural populations of both species. Sex ratio distortion is associated with spermatid degeneration in male carriers of Xd. Variation in sex ratios is caused by Y-linked and autosomal factors that decrease the intensity of meiotic drive. Y-linked polymorphism for resistance to drive exists in C. dalmanni in which a resistant Y chromosome reduces the intensity and reverses the direction of meiotic drive. When paired with Xd, modifying Y chromosomes (Ym) cause the transmission of predominantly Y-bearing sperm, and on average, production of 63% male progeny. The absence of sex ratio distortion in closely related monomorphic outgroup species suggests that this meiotic drive system may predate the origin of C. whitei and C. dalmanni. We discuss factors likely to be involved in the persistence of these sex-linked polymorphisms and consider the impact of Xd on the operational sex ratio and the intensity of sexual selection in these extremely sexually dimorphic flies.


2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Dorthe Yakymenko ◽  
Christine S Benn ◽  
Cesario Martins ◽  
Birgitte R Diness ◽  
Ane B Fisker ◽  
...  

2020 ◽  
Author(s):  
Rajendra Maharaj ◽  
Vishan Lakan ◽  
Kiash Maharaj

Abstract Background: Although great strides have been made in controlling malaria, the disease is of significant public health importance. Historically, efforts to control the vector has concentrated on adult vector control targeting the female Anopheles mosquitoes. As there is now a focus on eliminating residual malaria from KwaZulu-Natal, new strategies are being investigated to increase the impact of malaria elimination strategies. Greater attention is now being given to larval control, as a complementary measure to indoor residual spraying. However, there is a large gap in knowledge of the bionomics of the larval stages of this mosquito vector of malaria in South Africa. In order to focus on both larval and adult mosquito control methods, larval development and the reproductive stages of the vector were investigated since these variables influences our ability to impact mosquito populations through larval control. This study was therefore conducted to determine the peak eruption times and the emergent sex ratios, as well as the peak egg oviposition time in order to attack the mosquito when it is at its most vulnerable and when control interventions will have the most impact.Results: Oviposition studies showed two peaks corresponding with late evening and again just before dawn. Most eggs were also laid in the first half of the night (18h00 – midnight). Most mosquitoes erupted just after sunset and the sex ratios showed that twice as many females as males emerged. Females readily took a bloodmeal after oviposition or just after erupting. Hatch rate to viable first instar larvae was 74.5%.Conclusions: The results of this study have provided information as to when interventions would be most effective in controlling mosquito populations and have provided information that highlights the value of larval control as a complementary measure to adult mosquito control. The most vulnerable stages of the female Anopheles arabiensis are when they have just emerged or when they have just oviposited. Vector control strategies should be designed to target these vulnerable stages at the breeding sites in order to have maximum impact.


Author(s):  
Shoshana Grossbard

This chapter reviews models of marriage, with special emphasis on how the sex ratio can help explain outcomes such as marriage formation, the intramarriage distribution of consumption goods, labor supply, savings, type of relationship, divorce, and intermarriage. Economic models of marriage pioneered by Gary Becker are reviewed in the first section and then extended in the next section to incorporate the labor market for the work-in-household approach of Grossbard. The following section discusses challenges in identifying exogenous variation in sex ratios and presents empirical evidence on the impact of sex ratios on labor supply, consumption, savings, and several other outcomes.


2012 ◽  
Vol 93 (6) ◽  
pp. 859-864
Author(s):  
Z G Valeev ◽  
V G Belyakov ◽  
L Y Salyahova

Aim. To identify the factors influencing the strategy and tactics of treating patients with acute coronary syndrome; to define the impact of various stages of emergency care in total rate of under-24-hour in-patients mortality. Methods. The retrospective analysis of the in-patients medical charts, ambulance accompanying sheets and autopsy protocols of 303 patients who died during the first 24 hours after admission to the department of cardiology at Municipal Emergency Hospital №1, Kazan from January 1st, 2009 to December 31th, 2011. Results. The level of under-24-hour in-patients mortality in the emergency hospital remains considerably high without a tendency to fall. In economically active group of population male to female mortality ratio exceeds 1,8. Most patients are being brought to the hospital by ambulance crews which are not enough qualified and equipped to care for patients in a critical condition. Only 48.3% of admitted patients get medical aid before admission, although the share of patients admitted in a poor, critical or agonal condition is 89.8%. Conclusion. Decreasing under-24-hour mortality is a multidimensional and multifactorial problem, which demands a complex approach in all stages of providing medical care to be solved.


Author(s):  
Ryan Schacht ◽  
Mike Hollingshaus ◽  
Heidi Hanson ◽  
Tim Bruckner ◽  
Shane J Macfarlan ◽  
...  

While sex ratios at birth (SRB) have been shown to vary within and across populations, after over a century of research, explanations have remained elusive. A variety of ecological, demographic, economic, and social variables have been evaluated, yet their association with SRB has been equivocal. Here, in an attempt to shed light on this unresolved topic within the literature, we approach the question of what drives variation in SRB using detailed longitudinal data spanning the frontier-era to the early 20th century in a US population. Using several measures of environmental harshness, we find that fewer boys are born during challenging times. However, these results hold only for the frontier-era and not into a period of rapid industrialization. We argue that the mixed state of the literature may result from the impact and frequency of exogenous stressors being dampened in post-industrial societies.


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