scholarly journals Observable variations in human sex ratio at birth

2021 ◽  
Vol 17 (12) ◽  
pp. e1009586
Author(s):  
Yanan Long ◽  
Qi Chen ◽  
Henrik Larsson ◽  
Andrey Rzhetsky
Keyword(s):  
Sex Ratio ◽  
Large Scale ◽  
Agricultural Activity ◽  
Sex Ratio At Birth ◽  
Swedish Population ◽  
Geographical Regions ◽  
Very Large Datasets ◽  
National Patient ◽  
Ibm Watson ◽  
Selection Mechanisms

The human sex ratio at birth (SRB), defined as the ratio between the number of newborn boys to the total number of newborns, is typically slightly greater than 1/2 (more boys than girls) and tends to vary across different geographical regions and time periods. In this large-scale study, we sought to validate previously-reported associations and test new hypotheses using statistical analysis of two very large datasets incorporating electronic medical records (EMRs). One of the datasets represents over half (∼ 150 million) of the US population for over 8 years (IBM Watson Health MarketScan insurance claims) while another covers the entire Swedish population (∼ 9 million) for over 30 years (the Swedish National Patient Register). After testing more than 100 hypotheses, we showed that neither dataset supported models in which the SRB changed seasonally or in response to variations in ambient temperature. However, increased levels of a diverse array of air and water pollutants, were associated with lower SRBs, including increased levels of industrial and agricultural activity, which served as proxies for water pollution. Moreover, some exogenous factors generally considered to be environmental toxins turned out to induce higher SRBs. Finally, we identified new factors with signals for either higher or lower SRBs. In all cases, the effect sizes were modest but highly statistically significant owing to the large sizes of the two datasets. We suggest that while it was unlikely that the associations have arisen from sex-specific selection mechanisms, they are still useful for the purpose of public health surveillance if they can be corroborated by empirical evidences.

scholarly journals Human Sex Ratio at Birth: Mythical and Observable Trends

2020 ◽  
Author(s):  
Yanan Long ◽  
Qi Chen ◽  
Henrik Larsson ◽  
Andrey Rzhetsky
Keyword(s):  
Sex Ratio ◽  
The United States ◽  
Time Series Models ◽  
Agricultural Activity ◽  
Health Record ◽  
Sex Ratio At Birth ◽  
Regression Analyses ◽  
Mixed Effect ◽  
Effect Regression ◽  
Over Time

AbstractThe human sex ratio at birth (SRB) is defined as the ratio between the number of newborn boys to the total number of newborns per time unit. It is, typically, slightly greater than (more boys than girls) and fluctuates over time. In this study, we sought to “myth-check” previously reported associations (and test new hypotheses) using variants of mixed-effect regression analyses and time-series models on two very large electronic health record datasets, representing the populations in the United States and Sweden, respectively. Our results revealed that neither dataset supported models in which the SRB changed seasonally or in response to variations in ambient temperature, and that an increased level of a diverse array of pollutants were associated with lower SRBs. Moreover, we found that increased levels of industrial and agricultural activity, which served as proxies for water pollution, were also associated with lower SRBs.

scholarly journals Mythical and Observable Trends in Human Sex Ratio at Birth

2020 ◽  
Author(s):  
Yanan Long ◽  
Qi Chen ◽  
Henrik Larsson ◽  
Andrey Rzhetsky
Keyword(s):  
Sex Ratio ◽  
The United States ◽  
Time Series Models ◽  
Agricultural Activity ◽  
Health Record ◽  
Sex Ratio At Birth ◽  
Regression Analyses ◽  
Mixed Effect ◽  
Effect Regression ◽  
Over Time

AbstractThe human sex ratio at birth (SRB) is defined as the ratio between the number of newborn boys to the total number of newborns per time unit. It is, typically, slightly greater than (more boys than girls) and fluctuates over time. In this study, we sought to “myth-check” previously reported associations (and test new hypotheses) using variants of mixed-effect regression analyses and time-series models on two very large electronic health record datasets, representing the populations in the United States and Sweden, respectively. Our results revealed that neither dataset supported models in which the SRB changed seasonally or in response to variations in ambient temperature, and that an increased level of a diverse array of pollutants were associated with lower SRBs. Moreover, we found that increased levels of industrial and agricultural activity, which served as proxies for water pollution, were also associated with lower SRBs.

scholarly journals Holocene vegetation, fire and land use dynamics at Lake Svityaz, an agriculturally marginal site in northwestern Ukraine

2021 ◽  
Author(s):  
Christoph Schwörer ◽  
Erika Gobet ◽  
Jacqueline F. N. van Leeuwen ◽  
Sarah Bögli ◽  
Rachel Imboden ◽  
...  
Keyword(s):  
Bronze Age ◽  
Human Impact ◽  
Central Europe ◽  
Large Scale ◽  
Mixed Forest ◽  
Fire Risk ◽  
Late Glacial ◽  
Future Climate Change ◽  
Agricultural Activity ◽  
Fire Dynamics

AbstractObserving natural vegetation dynamics over the entire Holocene is difficult in Central Europe, due to pervasive and increasing human disturbance since the Neolithic. One strategy to minimize this limitation is to select a study site in an area that is marginal for agricultural activity. Here, we present a new sediment record from Lake Svityaz in northwestern Ukraine. We have reconstructed regional and local vegetation and fire dynamics since the Late Glacial using pollen, spores, macrofossils and charcoal. Boreal forest composed of Pinus sylvestris and Betula with continental Larix decidua and Pinus cembra established in the region around 13,450 cal bp, replacing an open, steppic landscape. The first temperate tree to expand was Ulmus at 11,800 cal bp, followed by Quercus, Fraxinus excelsior, Tilia and Corylus ca. 1,000 years later. Fire activity was highest during the Early Holocene, when summer solar insolation reached its maximum. Carpinus betulus and Fagus sylvatica established at ca. 6,000 cal bp, coinciding with the first indicators of agricultural activity in the region and a transient climatic shift to cooler and moister conditions. Human impact on the vegetation remained initially very low, only increasing during the Bronze Age, at ca. 3,400 cal bp. Large-scale forest openings and the establishment of the present-day cultural landscape occurred only during the past 500 years. The persistence of highly diverse mixed forest under absent or low anthropogenic disturbance until the Early Middle Ages corroborates the role of human impact in the impoverishment of temperate forests elsewhere in Central Europe. The preservation or reestablishment of such diverse forests may mitigate future climate change impacts, specifically by lowering fire risk under warmer and drier conditions.

scholarly journals Biogeography of acoustic biodiversity of NW Mediterranean coralligenous reefs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lucia Di Iorio ◽  
Manon Audax ◽  
Julie Deter ◽  
Florian Holon ◽  
Julie Lossent ◽  
...  
Keyword(s):  
Large Scale ◽  
Spatial Scales ◽  
Western Mediterranean ◽  
Ecosystem Functions ◽  
Marine Biodiversity ◽  
Predator Species ◽  
The North ◽  
Mediterranean Habitats ◽  
Geographical Regions ◽  
Nw Mediterranean

AbstractMonitoring the biodiversity of key habitats and understanding the drivers across spatial scales is essential for preserving ecosystem functions and associated services. Coralligenous reefs are threatened marine biodiversity hotspots that are challenging to monitor. As fish sounds reflect biodiversity in other habitats, we unveiled the biogeography of coralligenous reef sounds across the north-western Mediterranean using data from 27 sites covering 2000 km and 3 regions over a 3-year period. We assessed how acoustic biodiversity is related to habitat parameters and environmental status. We identified 28 putative fish sound types, which is up to four times as many as recorded in other Mediterranean habitats. 40% of these sounds are not found in other coastal habitats, thus strongly related to coralligenous reefs. Acoustic diversity differed between geographical regions. Ubiquitous sound types were identified, including sounds from top-predator species and others that were more specifically related to the presence of ecosystem engineers (red coral, gorgonians), which are key players in maintaining habitat function. The main determinants of acoustic community composition were depth and percentage coverage of coralligenous outcrops, suggesting that fish-related acoustic communities exhibit bathymetric stratification and are related to benthic reef assemblages. Multivariate analysis also revealed that acoustic communities can reflect different environmental states. This study presents the first large-scale map of acoustic fish biodiversity providing insights into the ichthyofauna that is otherwise difficult to assess because of reduced diving times. It also highlights the potential of passive acoustics in providing new aspects of the correlates of biogeographical patterns of this emblematic habitat relevant for monitoring and conservation.

scholarly journals Recent sex ratio at birth in China

2021 ◽  
Vol 6 (5) ◽  
pp. e005438
Author(s):  
Quanbao Jiang ◽  
Cuiling Zhang
Keyword(s):  
Sex Ratio ◽  
Normal Level ◽  
Decomposition Methods ◽  
Sex Ratio At Birth ◽  
Negative Effects ◽  
Female Fetus ◽  
The Past ◽  
Multiple Data ◽  
Child Policy ◽  
Second Births

BackgroundChina’s sex ratio at birth (SRB) has declined in the past decade but still exceeds the normal level. This study seeks to depict the SRB trend in the past two decades.MethodsWe depicted the SRB trend, including SRB by birth order, children composition, residence and hukou type, education, race and province using latest data available from multiple data sources and standardisation and decomposition methods.ResultsThe SRB remained around 120 in the first decade from 2000 to 2010, and recently declined and approached the normal level during 2010–2020. The SRB for second births and first births converged to the normal level, whereas the SRB for third and above births exceeded the normal level. The rising proportion of second births increased, whereas the decreasing proportion of first births reduced the overall SRB. Parents with only daughters are more likely to abort a female fetus in pursuit of a son, while parents with only sons are more likely to abort a male fetus in pursuit of a daughter. It also shows difference in SRB by residence, hukou type, educational attainment and race. Urban SRB was lower than rural SRB, by the residence and hukou type, but higher than rural SRB after being standardised. Provinces still exhibit differences by original categorised policy even after the implementation of the universal two-child policy.ConclusionsChina’s SRB has declined substantially during the past two decades, but the negative effects need to be tackled.

Akodon molinae (Rodentia Cricetidae), a new laboratory animal: breeding, management and reproductive performance

1980 ◽  
Vol 14 (2) ◽  
pp. 129-131 ◽  
Author(s):  
Maria Susana Merani ◽  
Marta Susana Lizarralde
Keyword(s):  
Sex Ratio ◽  
Reproductive Performance ◽  
Sexual Maturity ◽  
Laboratory Animal ◽  
Post Partum ◽  
Animal Breeding ◽  
Haemorrhagic Fever ◽  
Sex Ratio At Birth ◽  
Breeding Management ◽  
Laboratory Colony

Akodon molinae, a vole mouse widely distributed in central Argentina, shows remarkable chromosome polymorphisms. It is one of the natural reservoirs of the actiologic agent of haemorrhagic fever, and a laboratory colony could be of great help in investigating this disease. Pregnancy lasted 23 (range 21-25) days. Litters of 4-5 young were born to monogamous breeding pairs about every 30 days, with weaning at 26 days post partum. The sex ratio at birth was 505 males to 500 females: at weaning it was 460 to 440. Sexual maturity was attained at about 16 weeks of age in males and 12-20 weeks in females. Akodon molinae is easy to handle, but fighting and killing or neglect of young are problems.

scholarly journals Effects of assisted reproductive technologies on human sex ratio at birth

2014 ◽  
Vol 101 (5) ◽  
pp. 1321-1325 ◽  
Author(s):  
Walid E. Maalouf ◽  
Mina N. Mincheva ◽  
Bruce K. Campbell ◽  
Ian C.W. Hardy
Keyword(s):  
Sex Ratio ◽  
Assisted Reproductive Technologies ◽  
Reproductive Technologies ◽  
Sex Ratio At Birth

scholarly journals Statistical Study Of The Sex Ratio At Birth

1936 ◽  
Vol 36 (3) ◽  
pp. 381-401 ◽  
Author(s):  
W. T. Russell
Keyword(s):  
Sex Ratio ◽  
Excess Mortality ◽  
Statistical Study ◽  
Experimental Studies ◽  
Vital Statistics ◽  
Conception Rate ◽  
Sex Ratio At Birth ◽  
Live Births ◽  
Natal Mortality

That the number of male births always exceeds that of females is well known to students of vital statistics, but the biological law responsible for the phenomenon has not yet been adequately determined though various theories have been offered in explanation. It has been suggested that it resulted from a high male conception rate which, although modified by an excess mortality of male embryos, nevertheless produced a masculinity of matured births. In more recent times the conclusions drawn by MacDowell & Lord (1925, 1925 a) from their experimental studies with mice have failed to support this view. They claimed that there was no correlation between the pre-natal mortality and the masculinity of live births, that the primary ratio at conception was almost identical with that at birth. These contentions were criticized by Parkes (1923, 1926), who, whilst maintaining the doctrine that the ante-natal mortality of mice “falls preponderatingly upon the males”, stated “that it is quite obvious that a great deal more information is required before any coherent story of the factors governing the sex ratio at birth in the mouse (and all other mammals) can be put together”.

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