Increase In Proportion Of Females Research Articles

The changing profile of obstructive sleep apnea: long term trends in characteristics of patients presenting for diagnostic polysomnography.

IntroductionWe aimed to analyze long-term trends in characteristics of patients undergoing diagnostic polysomnography (PSG) and subsequently diagnosed with obstructive sleep apnea (OSA) to inform delivery of sleep services.Material and MethodsWe studied 24,510 consecutive patients undergoing PSG at a tertiary-care sleep service between 1989 and 2013. OSA was defined by an apnea hypopnea index (AHI)≥ 5 events/hour. Changes to hypopnea definition and flow sensing techniques in 2002 created two distinct AHI scoring periods: American Sleep Disorders Association (ASDA) 1989 - July 2002 and American Academy of Sleep Medicine (Chicago) from August 2002.ResultsOver 23.5 years there was a steady increase in proportion of females (15% to 45%), small increases in average age and BMI, and a small decline in socioeconomic status in the overall group. AHI varied between scoring periods both overall [ASDA 10.8/h (3.2-29.6), Chicago 24.3/h (11.8-48.1)] and in the large subgroup (80.7%) diagnosed with OSA [ASDA 20.7/h (10.6-44.1), Chicago 27.4/h (14.8-51.5)]. OSA diagnosis rates increased in the Chicago period (ASDA 66%, Chicago 91%). Increases in AHI and proportion diagnosed appeared better explained by changes in scoring methods than key OSA risk factors.ConclusionTemporal increases in proportion of females and decreases in socioeconomic status of people undergoing PSG may reflect greater community awareness of sleep disorders. Temporal increases in age and obesity are consistent with secular trends. Changes in scoring methods have major impacts on OSA diagnosis and judgement of disease severity, with important implications for contemporary resourcing of sleep services and interpretation of historical OSA data.

Frequency-dependent selection acting on the widely fluctuating sex ratio of the aphid Prociphilus oriens.

Frequency-dependent selection is a fundamental principle of adaptive sex ratio evolution in all sex ratio theories but has rarely been detected in the wild. Through long-term censuses, we confirmed large fluctuations in the population sex ratio of the aphid Prociphilus oriens and detected frequency-dependent selection acting on these fluctuations. Fluctuations in the population sex ratio were partly attributable to climatic factors during the growing season. Climatic factors likely affected the growth conditions of host plants, which in turn led to yearly fluctuations in maternal conditions and sex ratios. In the process of frequency-dependent selection, female proportion higher or lower than ca. 60% was associated with a reduction or increase in female proportion, respectively, the next year. The rearing of aphid clones in the laboratory indicated that mothers of each clone produced an increasing number of females as maternal size increased. However, the mean male number was not related to maternal size, but varied largely among clones. Given genetic variance in the ability to produce males among clones, selection should favour clones that can produce more numerous males in years with a high female proportion. Population-level sex allocation to females was on average 71%-73% for three localities and more female-biased when maternal conditions were better. This tendency was accounted for by the hypothesis of competition among foundresses rather than the hypothesis of local mate competition. We conclude that despite consistent operation of frequency-dependent selection, the sex ratio continues to fluctuate because environmental conditions always push it away from equilibrium.

Long-term exposure to environmentally relevant concentrations of progesterone and norgestrel affects sex differentiation in zebrafish (Danio rerio)

The aim of this study was to investigate the effects of progestins on the sex differentiation of zebrafish by measuring the sex ratio and transcriptions of genes related to sex differentiation (Amh, Dmrt1, Figa, Sox9a and Sox9b genes) as well as sex hormone levels and transcriptional expression profiles along the hypothalamic–pituitary–gonadal (HPG) and hypothalamic–pituitary–adrenal (HPA) axes in juvenile zebrafish. Exposure of zebrafish to 4, 33, 63ngL−1 progesterone (P4) or 4, 34, 77ngL−1 norgestrel (NGT) started at 20 days post fertilization (dpf) and ended at 60 dpf. The results showed that exposure to P4 caused a significant increase in proportion of females as well as significant down-regulation of Amh gene and up-regulation of Figa at a concentration of 63ngL−1. However, the shift in the sex ratio toward males was observed following exposure to 34 and 77ngL−1 NGT, which came along with the significant induction of Dmrt1 gene and inhibition of Figa gene. The sex hormones in exposed fish were measured with estrone being detected only in the fish exposed to the highest P4 concentration; whereas estradiol and androstenedione were detected only in the fish of the control and lowest NGT concentration. Furthermore, the increase in females was associated with the significant up-regulation of several key genes controlling the synthesis of sex hormones (i.e., Cyp17, Cyp19a1a and Hsd3b) following exposure to 63ngL−1 P4 whereas the significant down-regulation of Cyp11a1, Cyp17, Cyp19a1a and Hsd3b genes was observed in the male-biased populations caused by 34 and 77ngL−1 NGT. The overall results imply that both P4 and NGT could significantly affect sex differentiation in zebrafish, and that changes may be reflected by altered sex hormone levels and transcriptional expression profiles of genes related to synthesis of sex hormones.

Epidemiological shift in leprosy in a rural district of central India following introduction of multi-drug therapy (April 1986 to March 1992 and April 1992 to March 2002)

This study compares the epidemiological pattern of leprosy in pre- (April 1986 to March 1992) and post- (April 1992 to March 2002) multi-drug therapy (MDT) periods by retrospective analysis of 3274 registered leprosy cases in the rural field area of Regional Leprosy Training & Research Institute (RLTRI), situated in Raipur district of Chattisgarh province of Central India. The area has high endemicity for leprosy. In the post-MDT period, prevalence rate (PR) came down to less than 1 in 10, while New Case Detection Rate (NCDR) remained almost static during the two periods. Of the total new registered cases, 30.1% were registered during the pre-MDT period and the remaining 69.9% during the post-MDT period. Comparison of key leprosy variables among new registered cases showed a 2-fold rise in the proportion of MB cases (14.8 versus 27.6%), 3.0% increase in proportion of child cases (15.3 versus 18.6%) and cases with deformity grade II (3.1 versus 5.9%) and 4.0% increase in female proportion (41.4 versus 45.7%) during the post-MDT period. A decline was noted in mean age of registration for both MB (6.4 years) and PB (5.7 years) groups in the post-MDT period. While comparing treatment and outcome related variables, a marked fall of 25.8 months was recorded in treatment duration in the post-MDT period. The defaulter rate came down by 45.0% and relapse rate by more than 12.0% during the same period. The study shows that MDT is effective operationally, but continued ongoing transmission of infection and delayed diagnosis needs corrective action.

Pheromonally mediated colonization patterns in the velvet worm Euperipatoides rowelli (Onychophora)

AbstractWe demonstrate that the males of the peripatopsid Euperipatoides rowelli secrete a pheromone from crural papillae, which acts as an attractant to both males and females of the species. Patterns of colonization of decomposing logs and differences in sex ratio between incipient vs established populations indicate that males are the initial dispersers and colonizers, finding suitable log habitats in an exploratory fashion, while females subsequently colonize logs. This results in a disproportionately high frequency of males in newly colonized logs, followed by a gradual increase in female proportion. We argue that females use the aggregating pheromone secreted by males to target appropriate rotting log microhabitats, resulting in a clumped distribution of females compared to a more random distribution for males among recently colonized logs. This mode of colonization reduces the time that animals, especially females, spend outside the safety of suitable logs, and the risk‐taking strategy of male exploration may explain the marked sex ratio bias in favour of females in the population. Rapid and non‐random dispersal may also account for the contradictory evidence of unexpectedly high rates of colonization of new logs, yet a paucity of animals in leaf litter samples. The possibility that pheromone trails play a part in the dispersal process is discussed.

Statistical Analysis of Female Proportion among the Japanese Infant Population of 0-4 Year Olds

We deal with the problem of whether or not there is an increase in female proportion among 0-4 year olds in the Japanese population during the last 21 years. The validity of the use of a binomial model for analyzing the municipality-specific data of female proportion is examined using a beta-binomial model. It is suggested from a logistic regression analysis that there exists a difference of the female proportion of infant population among population-size-specific groups of municipalities. The highest proportion was observed for the rural group, and the lowest one was observed for the city group. A slight but statistically signifant increasing time-trend in female proportion among the city group is detected via a test with the null hypothesis that the proportions of females are all equal against an ordered alternative.

Spatial Regulation and Population Growth in the Wood Mouse Apodemus sylvaticus: Experimental Manipulations of Males and Females in Natural Populations

1. The role of male and female Apodemus sylvaticus (L.) in population regulation was investigated by their removal in two independent, replicated, field experiments, carried out in mixed woodland during the breeding season. 2. The removal of adult male A. sylvaticus during the breeding season resulted in a decline in male numbers but an increase in the number of adult females in manipulated areas. The effect of treatment was influenced by density at the start of the experiment. During the breeding season, adult male and female A. sylvaticus may compete for food. Thus, the removal of male A. sylvaticus may reduce competition for food with a concomitant increase in female numbers. 3. There was no evidence that adult male aggression influenced recruitment of young as recruitment was unaffected by male density or removal during the breeding season. The role of males in population regulation in A. sylvaticus therefore is limited to their impact on females and possibly through infanticide of nest young, rather than having a direct effect on the survival of weaned young. 4. The removal of female A. sylvaticus resulted in a fall in numbers of females and a concomitant increase in immigration of males and females on manipulated grids. Reproductive success of female immigrants was enhanced on grids where females were removed but did not result in an increase in the overall proportion of females that were reproductively active. It is suggested that reproductive activity in immigrant females is inhibited by resident females. 5. The enhanced dispersal of the females into areas from where resident females have been removed suggests that there are dispersing females in the population that may establish themselves in areas with few females and, in time, become reproductively active. 6. Male immigration during the female removal experiment was lowest on control grids where female density and numbers of reproductively active females were highest. Male A. sylvaticus may orientate towards areas that offer the greatest opportunity for copulation, regardless of absolute numbers of reproductively active females. 7. The results of the present experimental manipulations are consistent with the hypothesis that spatial density-dependent inhibition of breeding in female A. sylvaticus regulates population increase during the increase phase of the annual cycle. This mechanism may be overridden by superabundance of food in some years.