Pregnancy Complications Recur Independently of Maternal Vascular Malperfusion Lesions

Background Spontaneous abortions, intrauterine growth restriction, and preeclampsia are thought to be caused by defective placentation and are associated with increased risk of adverse outcomes in subsequent pregnancies. However, it is not known whether the recurrence of adverse outcomes is associated with the recurrence of placental pathology. We hypothesized that recurrent maternal vascular malperfusion (MVM) underlies the recurrence of adverse outcomes. Methods Using data from the National Collaborative Perinatal Project, we assessed the recurrence of pregnancy complications and MVM lesions (N = 3865), associations between a history of spontaneous abortions and MVM lesions or adverse outcomes in subsequent pregnancies (N = 8312), and whether the recurrence of pregnancy complications occurred independently of the presence of MVM lesions. Results The odds of an MVM lesion were higher for a woman who had had an MVM lesion in a previous pregnancy (aOR = 1.6; 95% CI 1.3–1.9), although this was marginally non-significant after adjusting for covariates such as gestational age, race and BMI. The odds of preeclampsia, a small-for-gestational-age infant, premature delivery and early pregnancy loss were 2.7–5.0 times higher if there had been that same adverse outcome in a previous pregnancy. A history of spontaneous abortions was associated with higher risk of a small-for-gestational-age baby (aOR = 2.4; 95% CI 1.7–3.4) and prematurity (aOR = 5.1; 95% CI 2.3–11.5 for extremely preterm), but not preeclampsia. The recurrence of adverse outcomes was significant when restricting analyses to women without MVM lesions. Similarly, associations between adverse outcomes and previous spontaneous abortions were significant when statistically controlling for the presence of MVM lesions, or excluding pregnancies with MVM lesions. Conclusions Women with adverse outcomes in one pregnancy are at higher risk of complications in subsequent pregnancies. However, there is significant recurrence of adverse outcomes even in the absence of MVM

Non-parametric Lagrangian biasing from the insights of neural nets

We present a Lagrangian model of galaxy clustering bias in which we train a neural net using the local properties of the smoothed initial density field to predict the late-time mass-weighted halo field. By fitting the mass-weighted halo field in the AbacusSummit simulations at z=0.5, we find that including three coarsely spaced smoothing scales gives the best recovery of the halo power spectrum. Adding more smoothing scales may lead to 2-5% underestimation of the large-scale power and can cause the neural net to overfit. We find that the fitted halo-to-mass ratio can be well described by two directions in the original high-dimension feature space. Projecting the original features into these two principal components and re-training the neural net either reproduces the original training result, or outperforms it with a better match of the halo power spectrum. The elements of the principal components are unlikely to be assigned physical meanings, partly owing to the features being highly correlated between different smoothing scales. Our work illustrates a potential need to include multiple smoothing scales when studying galaxy bias, and this can be done easily with machine-learning methods that can take in high dimensional input feature space.Comment: submitted to JCA

Oh! Where Art Thou

[Verse 1]Oh! where art thou, upon my brow, The ocean breeze is falling chill, And twilight pale her purple vail Folds softly round the distant hill the distant hill, From marshes damp, with ambar lamp, The mistic fire flies slowly steal, And on each flower, this witching hour, Has gently pressed its derry seal! Ah! Ah! [Verse 2] The moon is up; night’s sapphire cup, Is fill’d full of starry wine, That, brimming o’er, it seems to pour Into the blue and billows brine, and billows brine; For e’en as shine those eyes of thine, Upon my heart when thou art far, The stars engrave upon each wave, The shadowy image of a star. Ah! Ah! [Verse 3] Along the beach the seagull’s speech Comes sadly, like a voice of dole; But hark! I hear they footstp near, And music seems to thrill my soul. I breathe thy name; and winged with flame, The moonbeams thro’ the clustering boughs Now seem to pour; so cold before I listened to thy whispered vows

Birth of the first stars amidst decaying and annihilating dark matter

The first stars are expected to form through molecular-hydrogen (H$_2$) cooling, a channel that is especially sensitive to the thermal and ionization state of gas, and can thus act as a probe of exotic energy injection from decaying or annihilating dark matter (DM). Here, we use a toy halo model to study the impact of DM-sourced energy injection on the H$_2$ content of the first galaxies, and thus estimate the threshold mass required for a halo to form stars at high redshifts. We find that currently allowed DM models can significantly change this threshold, producing both positive and negative feedback. In some scenarios, the extra heating of the gas raises the halo mass required for collapse, whereas in others, energy injection lowers the threshold by increasing the free-electron fraction and catalyzing H$_2$ formation. The direction of the effect can be redshift-dependent. We also bracket the uncertainties from self-shielding of halos from Lyman-Werner radiation. Hence, exotic energy injection can both delay and accelerate the onset of star formation; we show how this can impact the timing of 21cm signals at cosmic dawn. We encourage detailed simulation follow-ups in the most promising regions of parameter space identified in this work.Comment: 32 pages, 13 figures, 3 table

Fast Radio Burst Tomography of the Unseen Universe

The discovery of Fast Radio Bursts (FRBs) at cosmological distances has opened a powerful window on otherwise unseen matter in the Universe. In the 2020s, observations of $>10^{4}$ FRBs will assess the baryon contents and physical conditions in the hot/diffuse circumgalactic, intracluster, and intergalactic medium, and test extant compact-object dark matter models.Comment: Science white paper submitted to the Astro2020 Decadal Survey. 15 pages, 3 color figure