Tight multi-messenger constraints on the neutron star equation of state from GW170817 and a forward model for kilonova light curve synthesis

We present a rapid analytic framework for predicting kilonova light curves following neutron star (NS) mergers, where the main input parameters are binary-based properties measurable by gravitational wave detectors (chirp mass and mass ratio, orbital inclination) and properties dependent on the nuclear equation of state (tidal deformability, maximum NS mass). This enables synthesis of a kilonova sample for any NS source population, or determination of the observing depth needed to detect a live kilonova given gravitational wave source parameters in low latency. We validate this code, implemented in the public MOSFiT package, by fitting it to GW170817. A Bayes factor analysis overwhelmingly ($B>10^{10}$) favours the inclusion of an additional luminosity source in addition to lanthanide-poor dynamical ejecta during the first day. This is well fit by a shock-heated cocoon model, though differences in the ejecta structure, opacity or nuclear heating rate cannot be ruled out as alternatives. The emission thereafter is dominated by a lanthanide-rich viscous wind. We find the mass ratio of the binary is $q=0.92\pm0.07$ (90% credible interval). We place tight constraints on the maximum stable NS mass, $M_{\rm TOV}=2.17^{+0.08}_{-0.11}$ M$_\odot$. For a uniform prior in tidal deformability, the radius of a 1.4 M$_\odot$ NS is $R_{1.4}\sim 10.7$ km. Re-weighting with a prior based on equations of state that support our credible range in $M_{\rm TOV}$, we derive a final measurement $R_{1.4}=11.06^{+1.01}_{-0.98}$ km. Applying our code to the second gravitationally-detected neutron star merger, GW190425, we estimate that an associated kilonova would have been fainter (by $\sim0.7$ mag at one day post-merger) and declined faster than GW170817, underlining the importance of tuning follow-up strategies individually for each GW-detected NS merger.Comment: Updated to match accepted version in MNRA

The stellar wind cycles and planetary radio emission of the Tau Boo system

Tau Boo is an intriguing planet-host star that is believed to undergo magnetic cycles similar to the Sun, but with a duration that is about one order of magnitude smaller than that of the solar cycle. With the use of observationally derived surface magnetic field maps, we simulate the magnetic stellar wind of Tau Boo by means of three-dimensional MHD numerical simulations. As the properties of the stellar wind depend on the particular characteristics of the stellar magnetic field, we show that the wind varies during the observed epochs of the cycle. Although the mass loss-rates we find (~2.7e-12 Msun/yr) vary less than 3 per cent during the observed epochs of the cycle, our derived angular momentum loss-rates vary from 1.1 to 2.2e32erg. The spin-down times associated to magnetic braking range between 39 and 78Gyr. We also compute the emission measure from the (quiescent) closed corona and show that it remains approximately constant through these epochs at a value of ~10^{50.6} cm^{-3}. This suggests that a magnetic cycle of Tau Boo may not be detected by X-ray observations. We further investigate the interaction between the stellar wind and the planet by estimating radio emission from the hot-Jupiter that orbits at 0.0462 au from Tau Boo. By adopting reasonable hypotheses, we show that, for a planet with a magnetic field similar to Jupiter (~14G at the pole), the radio flux is estimated to be about 0.5-1 mJy, occurring at a frequency of 34MHz. If the planet is less magnetised (field strengths roughly <4G), detection of radio emission from the ground is unfeasible due to the Earth's ionospheric cutoff. According to our estimates, if the planet is more magnetised than that and provided the emission beam crosses the observer line-of-sight, detection of radio emission from Tau Boo b is only possible by ground-based instruments with a noise level of < 1 mJy, operating at low frequencies.Comment: 15 pages, 10 figures, MNRAS accepte

Physiological Correlates of Volunteering

We review research on physiological correlates of volunteering, a neglected but promising research field. Some of these correlates seem to be causal factors influencing volunteering. Volunteers tend to have better physical health, both self-reported and expert-assessed, better mental health, and perform better on cognitive tasks. Research thus far has rarely examined neurological, neurochemical, hormonal, and genetic correlates of volunteering to any significant extent, especially controlling for other factors as potential confounds. Evolutionary theory and behavioral genetic research suggest the importance of such physiological factors in humans. Basically, many aspects of social relationships and social activities have effects on health (e.g., Newman and Roberts 2013; Uchino 2004), as the widely used biopsychosocial (BPS) model suggests (Institute of Medicine 2001). Studies of formal volunteering (FV), charitable giving, and altruistic behavior suggest that physiological characteristics are related to volunteering, including specific genes (such as oxytocin receptor [OXTR] genes, Arginine vasopressin receptor [AVPR] genes, dopamine D4 receptor [DRD4] genes, and 5-HTTLPR). We recommend that future research on physiological factors be extended to non-Western populations, focusing specifically on volunteering, and differentiating between different forms and types of volunteering and civic participation

Genom: kisah spesies manusia dalam 23 bab

Buku Genom: Kisah Spesies Manusia Dalam 23 Bab merupakan sebuah karya menarik dari Matt Ridley yang berupaya mengkaji tentang manusia. Bahasa yang disampaikan mudah dipahami, dan ringan sehingga cocok untuk dibaca oleh kalangan umum. Buku ini berupaya memaparkan tentang 23 kromosom manusia serta menelusuri bagaimana faktor pewarisan dan pengasuhan sama-sama berperan dalam kehidupan manusia.Sinopsis BukuGenom manusia, seperangkat lengkap gen yang terdapat dalam dua puluh tiga pasang kromosom, tidak lain adalah autobiografi spesies kita. Dengan telah diumumkannya "draf kasar" genom manusia, berarti kita, generasi yang beruntung ini, menjadi makhluk hidup pertama yang mampu membaca buku pintarnya sendiri, sekaligus memperoleh wawasan paling mendalam tentang makna hidup, arti menjadi manusia, kesadaran, atau fenomena jatuh sakit.la menemukan gen yang mungkin memengaruhi kecerdasan kita, gen yang memungkinkan kita berbahasa, gen yang memandu perkembangan tubuh dan otak kita, gen yang memungkinkan kita mengingat, gen yang menunjukkan keistimewaan unsur bawaan dan pengaruh pengasuhan, gen yang membebani kita dengan kecenderungan egois, gen yang saling berperang, juga gen yang merekam sejarah perpindahan penduduk.la menggali berbagai upaya penerapan genetika: untuk memahami penyakit Huntington hingga mengobati kanker. la mengupas munculnya kecemasan dan kengerian terhadap eugenika, serta implikasi filosofi dari memahami paradoks kehendak bebas

Genom. : Kisah spesies manusia dalam 23 bab.

Jakartaxxi, 384 p.; 23 cm

The Rational Optimist : How prosperity evolves

The New York Times --Bestselling author of Genome and The Red Queen offers a provocative case for an economics of hope, arguing that the benefits of commerce, technology, innovation, and change--cultural evolution--will inevitably increase human prosperity.https://scholar.dominican.edu/cynthia-stokes-brown-books-big-history/1078/thumbnail.jp