Every child a wanted child: mid-life women's experiences of contraception

This paper is based on qualitative research which found that the contraceptive pill had achieved a "hegemonic status" among some British women in their thirties. In addition, despite the risk of sexually transmitted diseases, the idea of using condoms was very unpopular, and the research suggests that this is linked to a reluctance to rely on male cooperation over contraception. This paper will further argue that the women generally chose methods that they felt would be in their own best interests, and were often exercising considerable agency within the constraints of their relationships. Moreover, by accepting the responsibility for contraception, the women not only gained sole control over their fertility, but contraception may be an area within heterosexuality where women can exercise power.

The debate on human automatism in mid-Victorian England

During the 1830s, Marshall Hall carried out innumerable experiments on a great variety of animals to establish the concept of a ‘reflex arc’. In France F.L.Goltz showed that decerebrate frogs were still capable of complex behaviours. Thomas Laycock in England and Ivan Sechenov in Russia sought to apply the reflex idea to the brain. This paper follows the debate in the periodical literature of mid-Victorian England and discusses the contributions of WB Carpenter, Herbert Spencer, TH Huxley, W Clifford and others. The previous outing of this issue in the post-Cartesian seventeenth century had been largely suppressed by ecclesiastical authority. In the nineteenth century ecclesiastical power had waned, at least in England, and the debate could take a more open form. As neurophysiology and behavioural science developed, with the widespread acceptance of Darwinian evolution, it became more and more difficult to deny that brain and mind were part of the natural world and subject to the usual laws of cause and effect. This, of course, had powerful implications for the human self-image and for jurisprudence. These implications are still with us and the work of neurophysiologists such as Benjamin Libet have only reinforced them. Should humans be regarded as ‘automata’ and, if so, what becomes of ‘free will’, ‘responsibility’, and the rule of law? The Victorian debate is still useful and relevant.

Fiber Bragg grating structures inscribed using 800nm femtosecond laser in single- and multi-core mid-IR glass fibers with their spectral, thermal and strain properties

Single- and multi-core passive and active germanate and tellurite glass fibers represent a new class of fiber host for in-fiber photonics devices and applications in mid-IR wavelength range, which are in increasing demand. Fiber Bragg grating (FBG) structures have been proven as one of the most functional in-fiber devices and have been mass-produced in silicate fibers by UV-inscription for almost countless laser and sensor applications. However, because of the strong UV absorption in germanate and tellurite fibers, FBG structures cannot be produced by UVinscription. In recent years femtosecond (fs) lasers have been developed for laser machining and microstructuring in a variety of glass fibers and planar substrates. A number of papers have been reported on fabrication of FBGs and long-period gratings in optical fibers and also on the photosensitivity mechanism using 800nm fs lasers. In this paper, we demonstrate for the first time the fabrication of FBG structures created in passive and active single- and three-core germanate and tellurite glass fibers by using 800nm fs-inscription and phase mask technique. With a fs peak power intensity in the order of 1011W/cm2, the FBG spectra with 2nd and 3rd order resonances at 1540nm and 1033nm in a single-core germanate glass fiber and 2nd order resonances between ~1694nm and ~1677nm with strengths up to 14dB in all three cores of three-core passive and active tellurite fibers were observed. Thermal and strain properties of the FBGs made in these mid-IR glass fibers were characterized, showing an average temperature responsivity of ~20pm/°C and a strain sensitivity of 1.219±0.003pm/µe.

Fiber Bragg gratings inscribed using 800nm femtosecond laser and a phase mask in singleand multi-core mid-IR glass fibers

For the first time, Fiber Bragg grating (FBG) structures have been inscribed in single-core passive germanate and three-core passive and active tellurite glass fibers using 800nm femtosecond (fs) laser and phase mask technique. With fs peak power intensity in the order of 1011W/cm2, the FBG spectra with 2nd and 3rd order resonances at 1540 and 1033nm in the germanate glass fiber and 2nd order resonances at ~1694 and ~1677nm with strengths up to 14dB in all three cores in the tellurite fiber were observed. Thermal responsivities of the FBGs made in these mid-IR glass fibers were characterized, showing average temperature responsivity ~20pm/°C. Strain responsivities of the FBGs in germanate glass fiber were measured to be 1.219pm/µe.

Theoretical studies of the mid-latitude ionosphere

Following a brief description of the atmosphere and ionosphere in Chapter I we describe how the equations of continuity and momentum for 0+, H+, He+, 0++ are derived from the formulations of St-Maurice and Schunk(1977) and Quegan et al.(1981) in Chapter II. In Chapter III we investigate the nature of the downward flow of protons in a collapsing post-sunset ionosphere. We derive an analytical form for the limiting temperature, we also note the importance of the polarization field term and concluded that the flow will remain subsonic for realistic conditions. The time-dependent behaviour of He+ under sunspot minimum conditions is investigated in Chapter IV. This is achieved by numerical solution of the 0+, H+ and,He+ continuity and momentum equations, treating He+ as a minor ion with 0+ , H+ as major ions. We found that He+ flows upwards during the day-time and downwards during the nighttime. He+ flux tube content reached a maximum on the 8th day of the integration period and started to decreasing. This is due to the large amount of H+ present at the late stages of the integration period which makes He+ unable to diffuse through the H+ layer away from the loss region. In Chapter V we investigate the behaviour of 0++ using sunspot maximum parameters. Although our results support the findings of Geis and Young (1981) that the large amounts of 0++ at the equator are caused mainly by thermal diffusion, the model used by Geis and Young overemphesizes the effect of thermal diffusion. The importance of 0++ - 0+ collision frequency is also noted. In Chapter VI we extend the work of Chapter IV, presenting a comparative study of H and He at sunspot minimum and sunspot maximum.In this last Chapter all three ions, O+ ,H+ and He+ , are treated theoretically as major ions and we concentrate mainly on light ion contents and fluxes. The results of this Chapter indicate that by assuming He+ as a minor ion we under-estimate He+ and over-estimate. H+. Some interesting features concerning the day to day behaviour of the light ion fluxes arise. In particular the day-time H+ fluxes decrease from day to day in contrast to the work of Murphy et al.(1976). In appendix.A we derive some analytical forms for the optical depth so that the models can include a realistic description of photoionization.

Terminal galactose residues on transferrin are increased in mid-life adults compared to young adults

Humans undergo biological ageing at different rates. This associates with functional decline in a number of physiological systems and increasing incidence of age-related pathologies. The discovery of robust biomarkers of ageing could be used to identify early divergence from a path of healthy ageing towards age-related disease. In the present study, we undertook proteomic analysis of plasma from healthy young men (mean age = 21.4 ± 1.5 years) and healthy mid-life men (mean age = 57.0 ±1.6 years). We identified twelve spots including transferrin, complement C3b and transthyretin that differed in abundance between the age groups. Transferrin spots showed an acidic pI shift in older males. Sandwich ELISAs were used to investigate the changes further. C3b levels were below the level of detection by ELISA and plasma concentrations of total transferrin or transthyretin were not different between the age groups studied here. However, analysis of transferrin N-glycan structures showed an increase in terminal galactose residues in older men, suggesting that the loss of terminal N-acetyl neuraminic acid residues contributes to the more acid pI of transferrin spots observed with age. Terminal galactosylation of transferrin may be a biomarker of healthy ageing and is now under investigation in the MARKAGE study.

Optimized design of high power mid-infrared Er3+, Pr3+ -codoped ZBLAN fiber laser

Based on the rate equations describing the operation of the Er3+, Pr3+ -codoped ZBLAN fiber lasers with different pump configurations, theoretical calculations that relate to the population characteristics and optimization of CW operation of high power Er3+, Pr3+ :ZBLAN double-clad fiber lasers are presented. Using the measured ET (energy-transfer), ETU (energy-transfer-upconversion) and CR (cross-relaxation) parameters relevant to Er3+, Pr3+ -codoped ZBLAN, a good agreement between the theoretical results from the model and recently reported experimental measurements is obtained. The effects on the slope efficiency of a number of laser parameters including fiber length, reflectance of the output mirror and pumping configuration are quantitatively analyzed and used for the design and optimization of high power Er3+, Pr3+ -codoped ZBLAN fiber lasers.