120 research outputs found
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 () 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 (90% credible
interval). We place tight constraints on the maximum stable NS mass, M. For a uniform prior in tidal
deformability, the radius of a 1.4 M NS is km.
Re-weighting with a prior based on equations of state that support our credible
range in , we derive a final measurement
km. Applying our code to the second
gravitationally-detected neutron star merger, GW190425, we estimate that an
associated kilonova would have been fainter (by 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
Adding 6 months of androgen deprivation therapy to postoperative radiotherapy for prostate cancer: a comparison of short-course versus no androgen deprivation therapy in the RADICALS-HD randomised controlled trial
Background
Previous evidence indicates that adjuvant, short-course androgen deprivation therapy (ADT) improves metastasis-free survival when given with primary radiotherapy for intermediate-risk and high-risk localised prostate cancer. However, the value of ADT with postoperative radiotherapy after radical prostatectomy is unclear.
Methods
RADICALS-HD was an international randomised controlled trial to test the efficacy of ADT used in combination with postoperative radiotherapy for prostate cancer. Key eligibility criteria were indication for radiotherapy after radical prostatectomy for prostate cancer, prostate-specific antigen less than 5 ng/mL, absence of metastatic disease, and written consent. Participants were randomly assigned (1:1) to radiotherapy alone (no ADT) or radiotherapy with 6 months of ADT (short-course ADT), using monthly subcutaneous gonadotropin-releasing hormone analogue injections, daily oral bicalutamide monotherapy 150 mg, or monthly subcutaneous degarelix. Randomisation was done centrally through minimisation with a random element, stratified by Gleason score, positive margins, radiotherapy timing, planned radiotherapy schedule, and planned type of ADT, in a computerised system. The allocated treatment was not masked. The primary outcome measure was metastasis-free survival, defined as distant metastasis arising from prostate cancer or death from any cause. Standard survival analysis methods were used, accounting for randomisation stratification factors. The trial had 80% power with two-sided α of 5% to detect an absolute increase in 10-year metastasis-free survival from 80% to 86% (hazard ratio [HR] 0·67). Analyses followed the intention-to-treat principle. The trial is registered with the ISRCTN registry, ISRCTN40814031, and ClinicalTrials.gov, NCT00541047.
Findings
Between Nov 22, 2007, and June 29, 2015, 1480 patients (median age 66 years [IQR 61–69]) were randomly assigned to receive no ADT (n=737) or short-course ADT (n=743) in addition to postoperative radiotherapy at 121 centres in Canada, Denmark, Ireland, and the UK. With a median follow-up of 9·0 years (IQR 7·1–10·1), metastasis-free survival events were reported for 268 participants (142 in the no ADT group and 126 in the short-course ADT group; HR 0·886 [95% CI 0·688–1·140], p=0·35). 10-year metastasis-free survival was 79·2% (95% CI 75·4–82·5) in the no ADT group and 80·4% (76·6–83·6) in the short-course ADT group. Toxicity of grade 3 or higher was reported for 121 (17%) of 737 participants in the no ADT group and 100 (14%) of 743 in the short-course ADT group (p=0·15), with no treatment-related deaths.
Interpretation
Metastatic disease is uncommon following postoperative bed radiotherapy after radical prostatectomy. Adding 6 months of ADT to this radiotherapy did not improve metastasis-free survival compared with no ADT. These findings do not support the use of short-course ADT with postoperative radiotherapy in this patient population
Duration of androgen deprivation therapy with postoperative radiotherapy for prostate cancer: a comparison of long-course versus short-course androgen deprivation therapy in the RADICALS-HD randomised trial
Background
Previous evidence supports androgen deprivation therapy (ADT) with primary radiotherapy as initial treatment for intermediate-risk and high-risk localised prostate cancer. However, the use and optimal duration of ADT with postoperative radiotherapy after radical prostatectomy remains uncertain.
Methods
RADICALS-HD was a randomised controlled trial of ADT duration within the RADICALS protocol. Here, we report on the comparison of short-course versus long-course ADT. Key eligibility criteria were indication for radiotherapy after previous radical prostatectomy for prostate cancer, prostate-specific antigen less than 5 ng/mL, absence of metastatic disease, and written consent. Participants were randomly assigned (1:1) to add 6 months of ADT (short-course ADT) or 24 months of ADT (long-course ADT) to radiotherapy, using subcutaneous gonadotrophin-releasing hormone analogue (monthly in the short-course ADT group and 3-monthly in the long-course ADT group), daily oral bicalutamide monotherapy 150 mg, or monthly subcutaneous degarelix. Randomisation was done centrally through minimisation with a random element, stratified by Gleason score, positive margins, radiotherapy timing, planned radiotherapy schedule, and planned type of ADT, in a computerised system. The allocated treatment was not masked. The primary outcome measure was metastasis-free survival, defined as metastasis arising from prostate cancer or death from any cause. The comparison had more than 80% power with two-sided α of 5% to detect an absolute increase in 10-year metastasis-free survival from 75% to 81% (hazard ratio [HR] 0·72). Standard time-to-event analyses were used. Analyses followed intention-to-treat principle. The trial is registered with the ISRCTN registry, ISRCTN40814031, and
ClinicalTrials.gov
,
NCT00541047
.
Findings
Between Jan 30, 2008, and July 7, 2015, 1523 patients (median age 65 years, IQR 60–69) were randomly assigned to receive short-course ADT (n=761) or long-course ADT (n=762) in addition to postoperative radiotherapy at 138 centres in Canada, Denmark, Ireland, and the UK. With a median follow-up of 8·9 years (7·0–10·0), 313 metastasis-free survival events were reported overall (174 in the short-course ADT group and 139 in the long-course ADT group; HR 0·773 [95% CI 0·612–0·975]; p=0·029). 10-year metastasis-free survival was 71·9% (95% CI 67·6–75·7) in the short-course ADT group and 78·1% (74·2–81·5) in the long-course ADT group. Toxicity of grade 3 or higher was reported for 105 (14%) of 753 participants in the short-course ADT group and 142 (19%) of 757 participants in the long-course ADT group (p=0·025), with no treatment-related deaths.
Interpretation
Compared with adding 6 months of ADT, adding 24 months of ADT improved metastasis-free survival in people receiving postoperative radiotherapy. For individuals who can accept the additional duration of adverse effects, long-course ADT should be offered with postoperative radiotherapy.
Funding
Cancer Research UK, UK Research and Innovation (formerly Medical Research Council), and Canadian Cancer Society
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
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