|
|
Variation in human secondary sex ratio after extraordinary natural, social and cultural events
Hubová, Hana ; Kaňková, Šárka (advisor) ; Dušek, Adam (referee)
The secondary sex ratio represents the proportion of male and female births and is usually slightly skewed towards male births. Changes in the secondary sex ratio may be induced by a variety of ultimate (evolutionary) or proximate (physiological) causes. These causes tend to be linked to external factors such as natural disasters, armed conflicts, terrorism and/or important cultural and sports events. Natural disasters cause major destruction of housing, infrastructure and loss of lives. Such events are likely to be followed by a decrease in the secondary sex ratio. Stress-induced selection in utero against males is one of the widely discussed causes related to this phenomenon. Armed conflicts and terrorism commonly have a negative impact on society as well, however, an increase in the secondary sex ratio was often observed in the post-war periods. Important cultural and sports events, along with holiday celebrations, have a mostly positive impact on the social climate. These events induce a sense of community and are likely to be followed by an increase in the secondary sex ratio 9 months later, which suggests higher coital rates during such events.
|
|
|
Development of the secondary sex ratio in the world
Mielniczková, Aneta ; Pavlík, Zdeněk (advisor) ; Kalibová, Květa (referee)
Development of secondary sex ratio in the world Abstract A secondary sex ratio is one of the surveyed population sex ratios. The goal is to describe the development of this index in 1950-2008 period in the world. First, the world is analyzed at the level of "subregion", followed by the analysis of the continents and then a summary of the results. Calculations for the level of "subregion" are compared with estimates of the UN. Analysis of the continent is displayed through the use of frequency tables, which are displaying the development of the index in time along with data availability. The summary of this paper consists of theoretical assumptions that could affect the child's sex. That is why, these assumptions are often associated with epigenetic factors influencing the sex of some animals. In the analysis of the secondary sex ratio the importance of data reliability, which plays a key role, is highlighted. Unfortunately, for Africa there had to be used insufficient data, in places where the value significantly fluctuated. On the contrary, the advanced countries have provided quality data. Most of the expected assumptions were confirmed by the results. Keywords: secondary sex ratio, the sex ratio at birth, influences on the sex
|
|
|
Development of the secondary sex ratio in India and China
Aubrecht, Vratislav ; Kurtinová, Olga (advisor) ; Fialová, Ludmila (referee)
Development of the secondary sex ratio in India and China Abstract The main objective of this thesis is to describe the population development and the development of the sex ratio at birth in India and China from 1950 to the present. In the majority of the populations of the world the sex ratio at birth (number of males born per 100 females) has usually values between 104- 106 male live births per 100 female live births, although determining exact borders varies depending on source. In some countries, the sex ratio at birth has risen to unnaturally high values in recent decades. This has happened in East and Southeast, South and West Asia or in Southeast Europe. In those countries, the son preference is deeply rooted. This is determined by many cultural, political, social and economic conditions. When two of the signs of gender discrimination are increasing sex ratio at birth and excessive female infant mortality, it brings a number of demographic consequences, which have further economic and social impact on society. No wonder many governments of the affected countries pay attention to this phenomenon, because those generated problems could affect and in some countries probably will affect society dozens years after sex ratio at birth returns to biologically normal values. Keywords: secondary sex ratio,...
|
|
|
Development of the secondary sex ratio in India and China
Aubrecht, Vratislav ; Kurtinová, Olga (advisor) ; Fialová, Ludmila (referee)
Development of the secondary sex ratio in India and China Abstract The main objective of this thesis is to describe the population development and the development of the sex ratio at birth in India and China from 1950 to the present. In the majority of the populations of the world the sex ratio at birth (number of males born per 100 females) has usually values between 104- 106 male live births per 100 female live births, although determining exact borders varies depending on source. In some countries, the sex ratio at birth has risen to unnaturally high values in recent decades. This has happened in East and Southeast, South and West Asia or in Southeast Europe. In those countries, the son preference is deeply rooted. This is determined by many cultural, political, social and economic conditions. When two of the signs of gender discrimination are increasing sex ratio at birth and excessive female infant mortality, it brings a number of demographic consequences, which have further economic and social impact on society. No wonder many governments of the affected countries pay attention to this phenomenon, because those generated problems could affect and in some countries probably will affect society dozens years after sex ratio at birth returns to biologically normal values. Keywords: secondary sex ratio,...
|
|
|
Development of the secondary sex ratio in the world
Mielniczková, Aneta ; Kalibová, Květa (referee) ; Pavlík, Zdeněk (advisor)
Development of secondary sex ratio in the world Abstract A secondary sex ratio is one of the surveyed population sex ratios. The goal is to describe the development of this index in 1950-2008 period in the world. First, the world is analyzed at the level of "subregion", followed by the analysis of the continents and then a summary of the results. Calculations for the level of "subregion" are compared with estimates of the UN. Analysis of the continent is displayed through the use of frequency tables, which are displaying the development of the index in time along with data availability. The summary of this paper consists of theoretical assumptions that could affect the child's sex. That is why, these assumptions are often associated with epigenetic factors influencing the sex of some animals. In the analysis of the secondary sex ratio the importance of data reliability, which plays a key role, is highlighted. Unfortunately, for Africa there had to be used insufficient data, in places where the value significantly fluctuated. On the contrary, the advanced countries have provided quality data. Most of the expected assumptions were confirmed by the results. Keywords: secondary sex ratio, the sex ratio at birth, influences on the sex
|
|
|
BABY BOY OR BABY GIRL
Zákostelná, Lucie ; Hebák, Petr (advisor) ; Burdychová, Bohdana (referee)
The thesis is mainly focused on the analysis and evaluation of the effects influencing the sex ratio of live births. After studying of the foreign language literature, main factors influencing the sex ratio are defined. Data used in the thesis (births by the sex) are retrieved from The Human Mortality Database, database of United Nations Statistics Division and from particular statistical offices. Based on the results of the exploratory data analysis, countries with unreliable data (data skewed due to the manipulation or due to the not appropriate standard of the registration of born) are specified. Subsequently, the countries with abnormal values of the sex ratio at birth resulting from the cultural traditions or technological development are defined. For countries with not evident influence of the factors mentioned the analysis of the relations and dependencies between sex ratio at birth and variables chosen (groups of the geographical, socioeconomics and demographical impacts). On the basis of this analysis it has been proved that the sex ratio at birth depends primarily, but not exclusively, on the total fertility rate and life expectancy.
|
guest ::
