Common Space of Spin and Spacetime

Given Lorentz invariance in Minkowski spacetime, we investigate a common space of spin and spacetime. To obtain a finite spinor representation of the non-compact homogeneous Lorentz group including Lorentz boosts, we introduce an indefinite inner product space (IIPS) with a normalized positive probability. In this IIPS, the common momentum and common variable of a massive fermion turn out to be ``doubly strict plus-operators''. Due to this nice property, it is straightforward to show an uncertainty relation between fermion mass and proper time. Also in IIPS, the newly-defined Lagrangian operators are self-adjoint, and the fermion field equations are derivable from the Lagrangians. Finally, the nonlinear QED equations and Lagrangians are presented as an example.Comment: 17 pages, a reference corrected, final version published on Foundations of Physics Letters in June of 2005, as a personal tribute to Einstein and Dira

Ion-imprinted polymers: synthesis, characterization and applications

Ion-imprinted polymers (IIPs) are created based on enzyme phenomenon, where these polymers exhibit selective recognition of metal ions in the presence of matrix ions. For that reason IIPs find many applications in sensors, solid phase extraction and membrane separation of metal ions. This review focuses on the synthesis, characterization and application of IIPs

On the Compression of Reproductive Spans: the case of Andhra Pradesh in India

Many women in Andhra Pradesh marry early, have two or three children and accept voluntary sterilization at very early ages. The state has recently succeeded in reducing fertility to near replacement levels. Data from the second round of the National Family Health Survey are used to examine the duration between first marriage and sterility by distinguishing different marriage cohorts of the 4,032 ever-married women aged 15-49 years. Life table and hazard models are used to understand the cohort effects on the time spend in the effective reproductive span. The cohort effects remain highly significant when controlling for other demographic, social and reproductive attitude characteristics. Sterilization acceptance among younger women explains the compression trends in reproductive spans. Women’s position as mothers is undergoing transition in Andhra Pradesh and they seem to make familial decisions much faster than the older generations did

Birthing practices of traditional birth attendants in South Asia in the context of training programmes

Traditional Birth Attendants (TBA) training has been an important component of public health policy interventions to improve maternal and child health in developing countries since the 1970s. More recently, since the 1990s, the TBA training strategy has been increasingly seen as irrelevant, ineffective or, on the whole, a failure due to evidence that the maternal mortality rate (MMR) in developing countries had not reduced. Although, worldwide data show that, by choice or out of necessity, 47 percent of births in the developing world are assisted by TBAs and/or family members, funding for TBA training has been reduced and moved to providing skilled birth attendants for all births. Any shift in policy needs to be supported by appropriate evidence on TBA roles in providing maternal and infant health care service and effectiveness of the training programmes. This article reviews literature on the characteristics and role of TBAs in South Asia with an emphasis on India. The aim was to assess the contribution of TBAs in providing maternal and infant health care service at different stages of pregnancy and after-delivery and birthing practices adopted in home births. The review of role revealed that apart from TBAs, there are various other people in the community also involved in making decisions about the welfare and health of the birthing mother and new born baby. However, TBAs have changing, localised but nonetheless significant roles in delivery, postnatal and infant care in India. Certain traditional birthing practices such as bathing babies immediately after birth, not weighing babies after birth and not feeding with colostrum are adopted in home births as well as health institutions in India. There is therefore a thin precarious balance between the application of biomedical and traditional knowledge. Customary rituals and perceptions essentially affect practices in home and institutional births and hence training of TBAs need to be implemented in conjunction with community awareness programmes

The distribution of charged amino acid residues and the Ca(2+) permeability of nicotinic acetylcholine receptors: a predictive model

Nicotinic acetylcholine receptors (nAChRs) are cation-selective ligand-gated ion channels exhibiting variable Ca(2+) permeability depending on their subunit composition. The Ca(2+) permeability is a crucial functional parameter to understand the physiological role of nAChRs, in particular considering their ability to modulate Ca(2+)-dependent processes such as neurotransmitter release. The rings of extracellular and intracellular charged amino acid residues adjacent to the pore-lining TM2 transmembrane segment have been shown to play a key role in the cation selectivity of these receptor channels, but to date a quantitative relationship between these structural determinants and the Ca(2+) permeability of nAChRs is lacking. In the last years the Ca(2+) permeability of several nAChR subtypes has been experimentally evaluated, in terms of fractional Ca(2+) current (Pf, i.e., the percentage of the total current carried by Ca(2+) ions). In the present study, the available Pf-values of nAChRs are used to build a simplified modular model describing the contribution of the charged residues in defined regions flanking TM2 to the selectivity filter controlling Ca(2+) influx. This model allows to predict the currently unknown Pf-values of existing nAChRs, as well as the hypothetical Ca(2+) permeability of subunit combinations not able to assemble into functional receptors. In particular, basing on the amino acid sequences, a Pf > 50% would be associated with homomeric nAChRs composed by different α subunits, excluding α7, α9, and α10. Furthermore, according to the model, human α7β2 receptors should have Pf-values ranging from 3.6% (4:1 ratio) to 0.1% (1:4 ratio), much lower than the 11.4% of homomeric α7 nAChR. These results help to understand the evolution and the function of the large diversity of the nicotinic receptor family

Does early childbearing and a sterilization-focused family planning programme in India fuel population growth?

Recent stagnation in the reduction of infant mortality in India can arguably be attributed to early child bearing practices and the lack of progress in lengthening birth intervals. Meanwhile, family planning efforts have been particularly successful in the southern states such as Andhra Pradesh, although family limitation is almost exclusively by means of sterilisation at increasingly younger ages. This paper examines the population impact of the unprecedented convergence of early childbearing trajectories in India and quantifies the potential implications stemming from the neglect of strategies that encourage delaying and spacing of births. The effects of adopting a ‘later, longer and fewer’ family planning strategy are compared with the continuation of fertility concentrated in the younger age groups. Results from the cohort component population projections suggest that a policy encouraging later marriage and birth spacing would achieve a future total population which is about 52 million less in 2050 than if the current early fertility trajectory is continued.census, family planning, fertility, India, National Family Health Surveys, population policies, population projections, Sample Registration Systems, sterilisation