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991.
Length of the follicular phase, time of insemination, coital rate and the sex of offspring 总被引:2,自引:2,他引:0
The penetrability of cervical mucus improves over the follicular phase.
When the length of the follicular phase varies due to variation in the
timing of the luteinizing hormone surge, mucus penetrability will also
improve as the phase lengthens. As selection for Y spermatozoa decreases
with improvements in mucus penetrability, sex ratios at conception should
decline in longer follicular phases. Sex ratios should also decline as the
time of insemination approaches ovulation unless hormonally-induced
improvements in penetrability are reduced by the debris left by earlier
inseminations.
相似文献
992.
Three-dimensional reconstruction of the human central sulcus reveals a morphological correlate of the hand area 总被引:2,自引:1,他引:1
Sastre-Janer FA; Regis J; Belin P; Mangin JF; Dormont D; Masure MC; Remy P; Frouin V; Samson Y 《Cerebral cortex (New York, N.Y. : 1991)》1998,8(7):641-647
One way to improve our understanding of cortical anatomy is to visualize
the three-dimensional (3D) shape of the cerebral sulci which is normally
hidden. Here, we reconstructed the 3D morphology of the central sulcus (CS)
in 17 normal subjects, using conventional magnetic resonance images and
dedicated software. We found that the 3D morphology was remarkably
consistent in all central sulci. Our analyses revealed three different
regions (upper, middle and lower), which were easily identifiable by
morphological criteria and sharply interconnected in the reconstructed CS.
These morphological regions appear to have a strong functional
significance, since the middle region corresponded precisely to the 'hand
area', as verified by hand vibration positron emission tomography
activation studies in eight cases. These data suggest that the 3D anatomy
of the cerebral cortex may facilitate sulcal recognition, and sulcal
subdivision into smaller morphological elements, bearing remarkable
relationships with functional cortical maps.
相似文献
993.
The authors developed a postprocessing technique, eigenimage filtering, to extract phase-dependent information from digital subtraction angiograms of the heart. This technique suppresses the interference from the right ventricle and left atrium and produces an image of the left ventricle and aorta that is substantially free of these overlap artifacts. The resultant eigenimages of the heart appear more like conventional ventriculograms than do digital subtraction angiograms and matched filtered images. 相似文献
994.
CA Rinaldi MRCP JF Coutts MRCP G Jackson MD FRCP 《International journal of clinical practice》2001,55(4):279-279
Left ventricular free wall rupture is thought to account for approximately 15% of deaths following acute myocardial infarction (MI). We present a case of left ventricular free wall rupture in a 64-year-old man following a lateral MI. The diagnosis was made with 2D and colour flow Doppler echocardiography. Unfortunately the patient died before emergency surgery, could be performed. 相似文献
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998.
Headache parameters, personality variables and stress factors were assessed in a sample of about 2,300 school pupils between 10 and 17 years of age in Amsterdam. More than 15% of the subjects reported headaches occurring weekly. Fear of failure and school problems, but not achievement motivation, had significant positive correlations with headache complaints after correction for differences in sex and age. Menarche and social class had little bearing in relation to the headache variables. From all reported causes of headache, stress was mentioned most frequently in both elementary and secondary schools. 相似文献
999.
BACKGROUND: Non-response analysis is often restricted to the influence of
age, sex and socio-economic status on response status. In this study the
health status of responders and non-responders was also compared. RESULTS:
Responders were comparable to non-responders with regard to the number of
diagnosed disorders as well as to the prevalences of disorders within body
systems. Non-responders only showed psychological disorders more often.
CONCLUSION: It is useful to assess the relation between non-response and
morbidity patterns in other studies as well, in order to detect selective
non-response and bias.
相似文献
1000.
A prospective, randomized, double-blind study for the evaluation of assisted hatching in patients with advanced maternal age 总被引:7,自引:3,他引:4
Lanzendorf SE; Nehchiri F; Mayer JF; Oehninger S; Muasher SJ 《Human reproduction (Oxford, England)》1998,13(2):409-413
The objective of this study was to determine if assisted hatching improved
the rates of implantation, clinical pregnancy and ongoing pregnancy for
in-vitro fertilization (IVF) patients aged > or =36 years. On the day of
oocyte aspiration, consenting patients were randomized according to whether
all embryos underwent the hatching procedure (hatched; n = 41) or all
embryos remained unhatched (controls; n = 48). Patients in both groups were
treated with methylprednisolone and doxycycline starting on the day of
oocyte retrieval and continuing for 4 days. The hatching procedure was
performed approximately 55 h after insemination on all potential embryos
for transfer and employed the release of acidified acid Tyrode's medium
against the zona pellucida to create an opening approximately 20 microm in
diameter. No significant differences were noted in the mean age, number of
oocytes aspirated and number of embryos transferred between the hatched and
control groups. In addition, no significant differences were observed in
the rates of implantation (11.1 versus 11.3%), clinical pregnancy (39.0
versus 41.7%) and ongoing pregnancy (29.3 versus 35.4%) between the hatched
and control groups respectively. These results suggest that assisted
hatching may have no significant impact on IVF success rates in the patient
population studied.
相似文献