Discovery of Two Relativistic Neutron Star-White Dwarf Binaries

We have discovered two recycled pulsars in relativistic orbits as part of the first high-frequency survey of intermediate Galactic latitudes. PSR J1157-5112 is a 44 ms pulsar and the first recycled pulsar with an ultra-massive (M > 1.14 Mo) white dwarf companion. Millisecond pulsar J1757-5322 is a relativistic circular-orbit system which will coalesce due to the emission of gravitational radiation in less than 9.5 Gyr. Of the ~40 known circular orbit pulsars, J1757-5322 and J1157-5112 have the highest projected orbital velocities. There are now three local neutron-star/white-dwarf binaries that will coalesce in less than a Hubble time, implying a large coalescence rate for these objects in the local Universe. Systems such as J1141-6545 (Kaspi et al. 2000) are potential gamma-ray burst progenitors and dominate the coalescence rate, whilst lighter systems make excellent progenitors of millisecond pulsars with planetary or ultra-low mass companions.Comment: 4 pages, to appear in ApJ Letters. Uses aastex v 5.0, emulateapj5.sty, apjfonts.st

Dwelling Quietly in the Rich Club: Brain Network Determinants of Slow Cortical Fluctuations

For more than a century, cerebral cartography has been driven by investigations of structural and morphological properties of the brain across spatial scales and the temporal/functional phenomena that emerge from these underlying features. The next era of brain mapping will be driven by studies that consider both of these components of brain organization simultaneously -- elucidating their interactions and dependencies. Using this guiding principle, we explored the origin of slowly fluctuating patterns of synchronization within the topological core of brain regions known as the rich club, implicated in the regulation of mood and introspection. We find that a constellation of densely interconnected regions that constitute the rich club (including the anterior insula, amygdala, and precuneus) play a central role in promoting a stable, dynamical core of spontaneous activity in the primate cortex. The slow time scales are well matched to the regulation of internal visceral states, corresponding to the somatic correlates of mood and anxiety. In contrast, the topology of the surrounding "feeder" cortical regions show unstable, rapidly fluctuating dynamics likely crucial for fast perceptual processes. We discuss these findings in relation to psychiatric disorders and the future of connectomics.Comment: 35 pages, 6 figure

Browsing throughout pregnancy:The longitudinal course of social media use during pregnancy

BackgroundThe number of people using social media has substantially increased over the past years. Previous studies have shown associations between social media overuse and mental health problems during pregnancy. The current study evaluates changes in social media use during pregnancy.MethodsPregnant women were recruited at their first antenatal appointment between January 2020 and July 2022 (N = 1135). The time spent on social media, frequency of social media use and problematic social media use, using the Bergen Social Media Addiction Scale (BSMAS), were assessed at 12, 20 and 28 weeks of pregnancy. Pearson r correlations and repeated measures ANOVAs were performed to assess possible changes in social media use over the course of pregnancy. Lastly, we stratified social media use throughout pregnancy for parity.ResultsThere was a significant change in social media use over time, for the time spent on social media, frequency of social media use and problematic social media use. Mean social media scores were the lowest at 12 weeks of pregnancy and increased significantly at 20 weeks of pregnancy, after which they remained stable at 28 weeks. Compared to multiparous women, primiparous women spent more time on social media at 20 weeks of pregnancy, but not at 12 or 28 weeks.ConclusionBecause overuse of social media has been associated with poor mental health, healthcare professionals should be aware of the intensity of social media use throughout pregnancy.<br/

The origin of the runaway high-mass X-ray binary HD153919/4U1700-37

Based on its Hipparcos proper motion, we propose that the high-mass X-ray binary HD153919/4U1700-37 originates in the OB association Sco OB1. At a distance of 1.9 kpc the space velocity of 4U1700-37 with respect to Sco OB1 is 75 km/s. This runaway velocity indicates that the progenitor of the compact X-ray source lost about 7 Msun during the (assumed symmetric) supernova explosion. The system's kinematical age is about 2 +/- 0.5 million years which marks the date of the supernova explosion forming the compact object. The present age of Sco OB1 is <8 Myr; its suggested core, NGC 6231, seems to be somewhat younger (~5 Myr). If HD153919/4U1700-37 was born as a member of Sco OB1, this implies that the initially most massive star in the system terminated its evolution within 30 Msun. With these parameters the evolution of the binary system can be constrained.Comment: 6 pages, latex, 3 embedded ps figures, to appear in A&