The male to female ratio at birth

The factors that influence the male to female ratio at birth are legion. Males are usually born in excess and stress decreases the ratio while wellbeing and good health tends to increase it. This paper reviews the multitudes of factors that have been implicated as affecting this ratio, from historical times to date.peer-reviewe

The male to female ratio at birth following the Scottish Independence Referendum, September 2014

Human male live births exceed female live births by approximately 3%. This sex ratio is conventionally expressed as M/F (male divided by total live births). Many factors have been implicated as influencing this ratio, such as stress. This phenomenon occurred following the Quebec sovereignty referendum of 1995. This study was carried out in order to ascertain whether the Scottish referendum of September 2014 had any effect on the M/F ratio in Scotland. Monthly live births by gender for Scotland were obtained from Scottish Office of National Records for the period January 2004 to July 2015. They were analysed for any significant period changes as witnessed in Quebec in 1995. There were 661166 total births (338850 male and 322316 female births), with an overall M/F of 0.5125 (95% CI: 0.5113-0.5137). There were no changes in M/F in the first five months after the referendum. However, there was a non-significant rise in M/F toward the end of 2014 which continued during much of 2015. The rise in M/F reached its peak in May-June 2015, 8-9 months after the referendum (M/F 0.5199 compared to M/F of 0.5124 for aggregated May-June values 2004-14). There was no significant drop in M/F in the Scottish population in relation to the Scottish referendum. This may be due to a type 2 error since this study was less powered (12 times smaller) than the Quebec study. The non-significant rise may have potentially been caused by increased coital rates as observed after the birth of Prince William in 1982 and for Hong Kong in relation to Dragon years. It will be interesting to analyse the rest of the UK data when this becomes officially available.peer-reviewe

Gendercide : a review of the missing women

The term gendercide was first coined in 1985 and refers to the deliberate extermination of persons of a particular sex. The notion and its potential consequences had been conceived as far back as 1793, when the Marquis Nicolas de Condorcet had speculated “what might be [the effect] on humankind [of] the discovery of a means of producing a male or female child according to the will of the parents [...]. Supposing that this is likely to become a common practice, [...] would it [not] lead to [changes] in the social relations of human beings, whose consequences could be harmful to the peaceable development of that indefinite perfectibility with expectations of which we have flattered humankind?”peer-reviewe

Terrorist attacks and the male to female ratio at birth : the bombings of Madrid (3/2004) and London (7/2005)

Introduction: Males are usually in excess of females at birth and the ratio is often expressed as M/F (male divided by total births). Several factors have been shown to be associated with changes in M/F, including major terrorist attacks. These are associated with a transient lowering of M/F for a one month period, three to five months after such events. This study was carried out in order to ascertain whether the Madrid March 2004 bombings and the London July 2005 bombings were similarly associated with changes in M/F in their respective populations. Methods: Monthly live births by gender for Madrid and Spain for 2004 and for England and Wales for 2005 were obtained from the two countries’ National Statistics Offices. Results: There were no significant dips in M/F for any of the months following the March 2004 bombings in Madrid or in Spain. There were no significant dips in M/F for any of the months following the July 2005 London bombings. Discussion: Research to date has shown M/F dips following catastrophic or tragic events, including major terrorist actions with extensive media coverage. Equivalent dips were not noted in this study for the terrorist acts in these instances. The reasons for this may be one or a combination of the following. The population size was not sufficiently large in order to detect an M/F dip. Alternatively, the events were not felt to be sufficiently momentous by the populace such that an M/F dip was not produced. Yet another possibility is that these particular populations are somehow hardier and more resistant to such influences. Not all terrorist events universally cause a significant reduction in M/F.peer-reviewe

Hepatitis B prevalence in two Maltese sub-populations

Hepatitis B surface antigen was measured by enzyme immunoassay in a random sample of 1258 healthy pregnant women attending the ante-natal clinics of St. Luke’s Hospital, Malta and Gozo General Hospital, Gozo, and 364 intravenous drug users attending the detoxification centre, SLH. Eight of the pregnant women and ten of the drug addicts were positive for the surface antigen, accounting for a prevalence of 6/1000 and 30/1000 for each cohort, respectively. This would be consistent with low/intermediate prevalence rate in accordance with WHO criteria.peer-reviewe

The male to female ratio at birth in different regions in Malta

Males are usually born in excess of females and the ratio of male births to female births is conventionally referred to as M/F. Many factors, including stress, privation and natural disasters are associated with a lowering of M/F. Malta has a North-South divide, with a more affluent North as opposed to a more industrialised and less prosperous South. This study was carried out in order to ascertain whether regional economic differences influenced M/F in Malta. Births by gender, year of birth and locality from 1999 to 2013 were subdivided into ten regions in a geographic distribution devised by the Department of Health Information and Research. Regions were also amalgamated into two groups of five which represented North-West and South-East Malta. The island of Gozo was considered separately. There were no statistically significant differences in M/F between the ten regions nor between North-West, South-East and Gozo regions. There were no significant secular trends in M/F in these regions. M/F declines under adverse environmental factors (including economic stress) but despite the overall poorer economic circumstances in the South of the Island, this study failed to show a significant difference in M/F by region. This may be due at least in part to the relatively small numbers involved. Alternatively, the purported socio-economic differences may not have been sufficiently large so as to skew M/F to statistically significant levels.peer-reviewe

Calibration of a Hydraulic Model for Seasonal Flooding in a Lowland River with Natural Diversions and Bathymetric Uncertainty, for Dam Downstream Impact Assessment

A method is developed to generate bank-full river main channel geometry, to complement an open-source Digital Elevation Model (DEM) and produce a calibrated hydraulic model reproducing the extent of historically observed overbank flooding. This approach relies on limited surveyed cross section and flow rate information and is potentially suitable for projects in developing countries where the availability of measured data is limited. The method presented is applied to the case of the seasonal flooding of the Baro River in the Gambela floodplain in Ethiopia, modelled with a two-dimensional hydraulic model. The simulated flooding extent for the 1990 wet season is compared with the observed flooding from 1990 satellite imagery and the expected flow interaction patterns with the near Alwero River, showing good agreement. The calibrated model is also used to show the impact of the planned TAMS hydropower dam on the Baro River flooding

Patterns of Land Use/Cover Dynamics in the Mountain Landscape of Tara Gedam and Adjacent Agro-Ecosystem, Northwest Ethiopia

This study analyzed land use/cover dynamics in the mountain landscape of Tara Gedam and adjacent agro-ecosystem of northwest Ethiopia over a period of 46 years (1957–2003). The changes were measured through interpretation of aerial photographs taken in 1957 and 1980, and Land-sat satellite image of 2003 using Arc gis 9.2 software, supported by focal group discussions and field visits. Three separate maps (for years 1957, 1980 and 2003) of the study area were produced and six major land use/cover classes were identified: dense forest, woodland, shrub land, grassland, riverine vegetation and cultivated and settlement land. The results indicated that the main land trajectory was from natural vegetation cover to settlement and cultivated land. The cultivated and settlement land coverage increased by 90.60% between 1957 and 2003. However, woodland, dense forest, riverine vegetation, shrub and grasslands coverage declined by 97.87, 71.04, 37.00, 9.02 and 3.03%, respectively. These could be mainly attributed to anthropogenic factors. Increasing demands of more land for cultivation and settlement, overgrazing, deforestation for fuel wood and construction have resulted in a dramatic shrinkage of the area under natural vegetation. The 1975 national land reform proclamation of the country had also contributed to the expansion of cultivated and settlement land. The implications of these changes are increased land degradation and loss of biodiversity affecting the livelihood of the community. It is suggested that the study area needs an immediate intervention for developing sustainable land use practices and to manage the remaining natural vegetation and to rehabilitate the degraded lands

Maternal factors and the male to female birth ratio in Malta

Introduction: The sex ratio at birth is commonly calculated as the total male live births divided by all live births, and is represented as M/F. A multitude of factors influence M/F, especially stress, which increases male foetal losses during pregnancy. This study was carried out in order to ascertain whether any maternal or perinatal relevant factors influenced M/F in Malta. Methods: National Obstetric Information System data was used for the period 2012-2015. Non-Maltese mothers were excluded. Factors analysed were maternal age, marital status, education, body mass index, regularity of menses, utilisation of assisted reproductive technology, previous diabetes mellitus, previous miscarriages, abortions, ectopic pregnancies, vaginal deliveries, caesarean sections, livebirths, early and late neonatal deaths, stillbirths and premature deliveries. Intra-partum conditions included infection, cardiovascular disorders and all forms of diabetes mellitus. Results: This study analysed 14498 births. None of the above mentioned variables was significantly linked to the M/F ratio. Discussion: Our dataset failed to find any variables that influenced M/F, including stressing variables. However our study may have been underpowered due to the small numbers of births and the relative rarity of the various conditions. Alternatively, in Malta, such variables may produce little or no stress due to hitherto unknown mitigating factor/s.peer-reviewe