Suchergebnisse

There is a general consensus in the literature that fertility differences between populations can be accounted for by differences in just four key proximate determinants: nuptiality, the postpartum non-susceptible period, contraception and abortion. Natural fecundibility is generally assumed to be constant between populations. This paper puts the theoretical and empirical case for a re-evaluation of that assumption, drawing on the under-utilized data on sexual activity collected in the Demographic Health Surveys (DHSs). Using data for married women in nine African countries, the analysis finds substantial population level differences in mean monthly coital frequency, which, if accurate, suggest an important demographic effect. There is a clear regional patterning to these differences, with levels of activity considerably lower among women in the West African populations included in the study than those from East and southern Africa. For West Africa in particular the data indicate the normality of exceptionally long periods of very infrequent or no intercourse by married women outside the period of postpartum abstinence. The findings challenge prevailing presumptions concerning susceptibility to pregnancy in marriage on which statistics for unmet need for family planning are derived. While doubts are raised over the precision of the sexual activity data used, the paper argues for the need for a greater effort to operationalize the 'proximate determinant of conception', not only for more accurate fertility modelling, but also as a planning tool for a more sensitive provision of family planning services in Africa.

The article is dedicated to Afro-Caribbean musical rituals as a form of response to exclusion from public sphere. The author claims that there are two key features of black music (in all the diversity of its genres): a) participatory character; b) dualism, manifested in a combination of a cheerful form and tragic content, hidden from an external observer. Starting from this thesis, the author places Notting Hill Carnival as a key chronotope of the (post)migratory situation in the center of his analysis. West Indian immigrants found themselves in this very situation in post-war Britain. The evolution of the Afro-Caribbean immigrants' carnival culture is considered in three stages. Firstly, the article discusses participation of the African slaves' descendants in the Trinidad street carnival. Then it proceeds to the transposition of this tradition into the context of the UK's capital. Further, the use of carnival forms of protest against racism in modern Britain is discussed. On the one hand, the study reveals a trend towards significant expansion of the "black music" adherents circle due to its subversive potential. On the other hand, it discovers the limits of solidarity among those who are prone to social stigmatization due to their ethnocultural otherness.

While the concept of friendship has been largely invisible within Western political debate, in the international political domain, 'friendship' and the language of friends have been prominent in treaties and alliances between nations. Database searches on the topic of 'politics and friendship' locate predominantly references concerning relationships between states. However, it has been war and enmity rather than friendship that has dominated analysis in international relations literature. In this article we provide a history of international treaties, focusing in particular on those named as friendship treaties. We will discuss the use of concepts and terminology related to friendship and the nomenclature associated with international alliances. It will be argued that friendship is more a tool of public relations and spin, rather than diplomacy and peace-building, and the cynical use of friendship does not sit easily with the Nehruvian concept of friendship as an important method of diplomacy that can act as a path to peace, goodwill and understanding between states and nations. Adapted from the source document.

Bacillus subtilisParB forms multimeric networks involving non-specific DNA bindingleading to DNA condensation. Previously, we found that an excess of the free C-terminal domain(CTD) of ParB impeded DNA condensation or promoted decondensation of pre-assemblednetworks (Fisher et al., 2017). However, interpretation of the molecular basis for this phenomenonwas complicated by our inability to uncouple protein binding from DNA condensation. Here, wehave combined lateral magnetic tweezers with TIRF microscopy to simultaneously control therestrictive force against condensation and to visualise ParB protein binding by fluorescence. Atnon-permissive forces for condensation, ParB binds non-specifically and highly dynamically to DNA.Our new approach concluded that the free CTD blocks the formation of ParB networks byheterodimerisation with full length DNA-bound ParB. This strongly supports a model in which theCTD acts as a key bridging interface between distal DNA binding loci within ParB networks. ; Financial support from AEI/FEDER, UE (BFU2017-83794-P) and from European Research Council (ERC) under the European Union's Horizon 2020 Research and Innovation programme (grant agreement no. 681299). JM-M acknowledges a predoctoral PhD fellowship from the Basque Country Government Department of Education, Language Policy and Culture (ref.PRE_2013_11_1174). GLMF was supported by the Biotechnology and Biological Sciences Research Council (1363883). MSD was supported by the Wellcome Trust (100401 and 077368). ; Peer reviewed

Bacillus subtilis ParB forms multimeric networks involving non-specific DNA binding leading to DNA condensation. Previously, we found that an excess of the free C-terminal domain (CTD) of ParB impeded DNA condensation or promoted decondensation of pre-assembled networks (Fisher et al., 2017). However, interpretation of the molecular basis for this phenomenon was complicated by our inability to uncouple protein binding from DNA condensation. Here, we have combined lateral magnetic tweezers with TIRF microscopy to simultaneously control the restrictive force against condensation and to visualise ParB protein binding by fluorescence. At non-permissive forces for condensation, ParB binds non-specifically and highly dynamically to DNA. Our new approach concluded that the free CTD blocks the formation of ParB networks by heterodimerisation with full length DNA-bound ParB. This strongly supports a model in which the CTD acts as a key bridging interface between distal DNA binding loci within ParB networks. ; European Research Council (ERC) (Grant agreement no. 681299). ; Basque Country Government Department of Education, Language Policy and Culture.(ref.PRE_2013_11_1174). ; Biotechnology and Biological Sciences Research Council. (1363883). ; Wellcome Trust (100401 and 077368). ; Peer reviewed

PurposePrevious research has predominantly approached the concept of entrepreneurial opportunities from either one of two perspectives: opportunities exist as objective phenomena in the environment waiting to be discovered by alert entrepreneurs, or opportunities are subjectively perceived and even created by individual entrepreneurs. This paper aims to put forward a framework of opportunity perception which demonstrates that all entrepreneurial opportunities possess both objective and subjective qualities, thus helping reconcile both perspectives.Design/methodology/approachA conceptual framework is developed, based on previous literature and insights from entrepreneurship, economics, psychology and related disciplines.FindingsVarious perspectives presented in previous research can be combined into a coherent framework that summarizes the components of entrepreneurial opportunity perception. Testable propositions are provided for future research.Originality/valueThe authors show that elements of both subjective perception and objective market conditions contribute to recognized entrepreneurial opportunities. Also, they show that while the perception and pursuit of opportunity is fundamentally idiosyncratic to each entrepreneur, the success of an entrepreneurial endeavor is constrained by the objective conditions of opportunity.