We present a rest-UV selected sample of 32 lensed galaxies at \(z\sim 2\) observed with joint Keck/LRIS rest-UV and Keck/MOSFIRE rest-optical spectra behind the clusters Abell 1689, MACS J0717, and ...MACS J1149. The sample pushes towards the faintest UV luminosities observed (\(-19 \le {\rm M_{\rm UV}} \le -17\)) at this redshift. The fraction of dwarf galaxies identified as Ly\(\alpha\) emitters (\(\rm EW \ge 20\ \overset{\lower.5em\circ}{\mathrm{A}}\)) is \({\rm X_{\rm LAE}}=25^{+15}_{-10}\%\). We use the Balmer lines and UV continuum to estimate the intrinsic EW allowing us to distinguish the effects of the ionizing spectra and Ly\(\alpha\) escape fraction on the observed EW distribution. Fainter galaxies (\(\rm M_{\rm UV} > -19\)) show larger intrinsic EWs and escape fractions than brighter galaxies. Only galaxies with intrinsic EWs greater than 40\(\ \overset{\lower.5em\circ}{\mathrm{A}}\) have escape fractions larger than 0.05. We find an anti-correlation between the escape fraction and \(\rm A_V\) as well as UV spectral slope. The volumetric escape fraction of our sample is \(f_{\rm esc}^{\rm Ly\alpha} = 4.59^{+2.0}_{-1.4}\%\) in agreement with measurements found elsewhere in the literature. About half of the total integrated Ly\(\alpha\) luminosity density comes from galaxies with \({\rm EW}_{\rm obs}>20\ \overset{\lower.5em\circ}{\mathrm{A}}\).
Background. We wanted to study a possible association between smoking during pregnancy and preterm birth.
Methods. A population based prospective study was performed among 7,236 consecutive ...pregnancies over seven years delivered at one birth clinic. Smoking habits were obtained at a routine ultrasound examination around 18 gestational weeks, and preterm birth was defined as delivery of a child between 24 and 37 gestational weeks. We estimated relative risk (odds ratio) between smoking, possible confounding variables and preterm birth using multiple logistic regression analysis.
Results. Overall, 1,769 (25%) women said that they smoked every day during their pregnancy. The smoking women had an increased risk of preterm delivery compared with non‐smokers (odds ratio 1.53, 95% confidence interval 1.24, 1.89). However, this association was only demonstrated among the multiparous women (odds ratio 1.88, 95% confidence interval 1.39, 2.54). The association was statistically significant after adjusting for maternal age, diabetes, cervical conization, preeclampsia, placental abruption and placenta previa in a multivariate analysis, and we observed a dose‐response effect of maternal smoking on preterm birth among multiparous women.
Conclusion. For multiparous women smoking during pregnancy increases the risk of preterm delivery, and there seems to be a dose‐response effect of smoking.
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