2,321 research outputs found
The regulatory cliff edge between contraception and abortion: the legal and moral significance of implantation
In regulating the voluntary interruption of pregnancy, English law has accorded particular significance to two biological events. First, ‘viability’, the moment when a fetus is said to acquire the capacity for independent life, plays an important role in grounding restrictions on access to legal abortion later in pregnancy. Second, equally significantly but far less frequently discussed, ‘implantation’ marks the point in pregnancy from which abortion laws apply. This paper focuses on this earlier biological event. It suggests that an unquestioning reliance on implantation as marking an appropriate moment of transition between two radically different legal frameworks is deeply problematic and is rendered still less sustainable in the light of the development of new technologies that potentially operate shortly after the moment of implantation
Effect of tamoxifen alone and in combination with RU 486 on the endometrium in the mid-luteal phase
The effects of RU 486 combined with tamoxifen and tamoxifen alone on hormonal parameters and endometrial development at the time of implantation were studied. Measurements of cytosolic oestrogen and progesterone receptors in endometrium and placental protein 14 (PP14) in plasma were also included. Three dosage schedules were used: single oral dose of 40 mg tamoxifen alone and in combination with 200 mg RU 486, and 40 mg tamoxifen for three consecutive days starting on the first day after the luteinizing hormone (LH) surge. The combined treatment prolonged the luteal phase (P < 0.05) and increased the plasma levels of progesterone. A single dose of tamoxifen did not affect the bleeding pattern and plasma hormone levels, but raised plasma oestradiol and LH with the 3-day treatment. The endometrium was retarded after the combined and the 3-day treatment with tamoxifen. Concentrations of cytosolic progesterone receptors were higher after the combined therapy, but were unaffected after tamoxifen only. PP14 levels were higher (P < 0.05) after repeated tamoxifen doses than in controls, but were lower with combined treatment. Progesterone and oestrogen are evidently necessary for endometrial maturation during the secretory phase of the menstrual cycle. PP14 levels in plasma cannot be used for clinical assessments of endometrial function because high levels coincide with disturbed endometrial developmen
The effect of RU486 administered during the proliferative and secretory phase of the cycle on the bleeding pattern, hormonal parameters and the endometrium
Seventeen healthy women aged 24-45 years with regular menstrual periods, proven fertility and not using steroidal contraceptives or IUD were recruited for the study. The volunteers were followed during one control, one treatment and one follow-up cycle. Daily morning urine samples were obtained during the control and the treatment cycle. The samples were analysed with regard to pregnanediol glucuronide (P2-G), oestrone glucuronide (E1-G), oestradiol (E2), progesterone (P4), LH and creatinine. During the entire 3-month study the subjects kept a record of uterine bleeding and side effects. The subjects received 50 mg RU486 daily either on cycle days 7-10 (n = 7) or on cycle days 20-23 (n = 10). An endometrial biopsy was taken on cycle day 10 in the first group and on cycle days 21-28 in the second group of patients. Treatment during the proliferative phase caused significant prolongation of the cycle length due to a delay of the oestrogen and LH surge. However, once the oestrogen concentration started to increase, the remaining part of the cycle was normal. The length of the follow-up cycle was similar to that of the control cycle. The morphology of the endometrium did not differ from control samples taken from untreated women at the same time of the cycle. All ovulating women (n = 9) treated in the mid-luteal phase started to bleed on the 3rd to 4th day of the treatment. In four of these women the bleeding was scanty and followed by a menstrual-like bleeding at expected time, while in the remaining five volunteers the treatment bleeding was heavier and not followed by a new bleeding until a month later. The duration of the secretory phase was 16.5 ± 1.3 days in women with two bleeding episodes and 11.8 ± 1.9 days in women with one bleeding episode (P < 0.05). The hormonal parameters were similar in both groups up to the start of the treatment. In the patients with one bleeding episode, the treatment was associated with a reduction in progesterone concentration, while in the patients with two bleeding episodes the progesterone concentration remained elevated until the second bleeding episode. Light microscopic examination of the endometrium revealed unique changes in the endometrial morphology. The results indicate that RU486 acts mainly on the endometrium but a direct or indirect effect on the corpus luteum cannot be excluded. The age of the corpus luteum may be of importance for its susceptibility to RU486 treatmen
Prevalence of HIV and Associated Risks of Sex Work among Youth in the Slums of Kampala.
Purpose. The purpose of this study is to examine the prevalence of and risk factors for engaging in sex work among youth living in Kampala, Uganda. Methods. Analyses are based on a cross-sectional study (N = 1,134) of youth aged 12-18 years, living in the slums of Kampala, conducted in Spring of 2014. The analytic sample consisted of only sexually active youth (n = 590). Youth who reported engaging in sex work were compared to youth who did not report sex work. Multivariable analyses were conducted to examine factors associated with sex work. Results. Among the youth who had ever had sexual intercourse (n = 590), 13.7% (n = 81) reported engaging in sex work. Self-reported HIV prevalence was 13.9% among the total sample (n = 81) and 22.5% (n = 18) among youth engaged in sex work. Engaging in sex work was associated with being female (AOR 10.4; 95% CI: 3.9, 27.4), being an orphan (AOR 3.8; 95% CI: 1.7, 8.4), ever drinking alcohol (AOR 8.3; 95% CI 3.7, 19.0), and experiencing any rape (AOR 5.3; 95% CI: 2.9, 9.5). Discussion. The reported prevalence of sex work is high among youth in the slums of Kampala and is associated with high HIV prevalence, ever drinking alcohol, previously being raped, and being an orphan
Giant Oscillations of Acoustoelectric Current in a Quantum Channel
A theory of d.c. electric current induced in a quantum channel by a
propagating surface acoustic wave (acoustoelectric current) is worked out. The
first observation of the acoustoelectric current in such a situation was
reported by J. M. Shilton et al., Journ. Phys. C (to be published). The authors
observed a very specific behavior of the acoustoelectric current in a
quasi-one-dimensional channel defined in a GaAs-AlGaAs heterostructure by a
split-gate depletion -- giant oscillations as a function of the gate voltage.
Such a behavior was qualitatively explained by an interplay between the
energy-momentum conservation law for the electrons in the upper transverse mode
with a finite temperature splitting of the Fermi level. In the present paper, a
more detailed theory is developed, and important limiting cases are considered.Comment: 7 pages, 2 Postscript figures, RevTeX 3.
Non-Equilibrium Magnetization in a Ballistic Quantum Dot
We show that Aharonov-Bohm (AB) oscillations in the magnetic moment of an
integrable ballistic quantum dot can be destroyed by a time dependent magnetic
flux. The effect is due to a nonequilibrium population of perfectly coherent
electronic states. For real ballistic systems the equilibrization process,
which involves a special type of inelastic electron backscattering, can be so
ineffective, that AB oscillations are suppressed when the flux varies with
frequency 10-10 s. The effect can be used to
measure relaxation times for inelastic backscattering.Comment: 11 pages LaTeX v3.14 with RevTeX v3.0, 3 post script figures
available on request, APR 93-X2
Animals in the curriculum : a questionnaire to elementary school biology teachers
The usage of animals for different purposes in today’s society is widespread, and animal welfare
has become a public concern. In order to secure good welfare for these animals it is of great
importance to gain knowledge about ethology and animal protection legislation early in life.
Improved knowledge regarding animal welfare has been stated as an important key in the European
Commission’s strategy for protection and increased welfare of animals. The children are our future
population and have the possibility to change the welfare standards of many animals with their
consuming habits and contribute to a general increased welfare by tending to animals needs and
behaviour. To gain this knowledge children need adequate education, and preferable already at an
early age. Several earlier studies have confirmed the positive effects of education on knowledge and
attitudes towards different kind of animals. Despite this matter, the elementary schools are not
promoting this knowledge and the words ethology, animal welfare and animal protection are
completely absent in the primary school biology curricula. This study’s aim was to investigate if,
and to what extent, teachers are implementing these subjects in their biology lessons. Data was
collected through a questionnaire and distributed via groups for teachers on social media. Although
a small sample size was obtained in this study, the result indicated that neither animal welfare,
ethology nor animal protection is implemented in the biology lessons to any greater extent. In order
to change this matter, the teachers imply that the subjects must be described in the curriculum for
them to include them in their teaching. These results could indicate that the biology curricula need
to reform to promote the teaching of these subjects in school. Future studies ought to investigate a
greater sample size and an evaluation of what kind of knowledge and attitudes towards animals the
present biology curricula is promoting would also be beneficial.
Keywords: Curriculum, biology, education, animal welfare, ethology, animal protectio
Nonequilibrium orbital magnetization of strongly localized electrons
The magnetic response of strongly localized electrons to a time-dependent
vector potential is considered. The orbital magnetic moment of the system, away
from steady-state conditions, is obtained. The expression involves the
tunneling and phonon-assisted hopping currents between localized states. The
frequency and temperature dependence of the orbital magnetization is analyzed
as function of the admittances connecting localized levels. It is shown that
quantum interference of the localized wave functions contributes to the moment
a term which follows adiabatically the time-dependent perturbation.Comment: RevTeX 3.
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